U.S. patent application number 11/449629 was filed with the patent office on 2006-10-12 for method and apparatus for image forming capable of effectively collating a stack of single/double-sided recording sheets in a desired ejection tray.
Invention is credited to Hideaki Mochimaru, Yasukuni Omata.
Application Number | 20060227390 11/449629 |
Document ID | / |
Family ID | 27344223 |
Filed Date | 2006-10-12 |
United States Patent
Application |
20060227390 |
Kind Code |
A1 |
Mochimaru; Hideaki ; et
al. |
October 12, 2006 |
Method and apparatus for image forming capable of effectively
collating a stack of single/double-sided recording sheets in a
desired ejection tray
Abstract
An image transfer apparatus includes a first transfer mechanism
configured to transfer an image onto a first surface of a recording
sheet. The image transfer apparatus also includes a second transfer
mechanism configured to transfer an image onto a second surface of
the recording sheet, and a controller configured to select one of a
first case, in which the first transfer mechanism transfers a first
original image onto the first surface of the recording sheet, or a
second case, in which the second transfer mechanism transfers the
first original image onto the second surface of the recording
sheet.
Inventors: |
Mochimaru; Hideaki;
(Kanagawa-ken, JP) ; Omata; Yasukuni;
(Kanagawa-ken, JP) |
Correspondence
Address: |
C. IRVIN MCCLELLAND;OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Family ID: |
27344223 |
Appl. No.: |
11/449629 |
Filed: |
June 9, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09915398 |
Jul 27, 2001 |
7061637 |
|
|
11449629 |
Jun 9, 2006 |
|
|
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Current U.S.
Class: |
358/498 ;
358/1.15 |
Current CPC
Class: |
G06K 15/00 20130101;
G06K 2215/0088 20130101; G06K 15/16 20130101 |
Class at
Publication: |
358/498 ;
358/001.15 |
International
Class: |
G06F 3/12 20060101
G06F003/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 2000 |
JP |
2000-231576 |
Jul 31, 2000 |
JP |
2000-231575 |
Jun 19, 2001 |
JP |
2001-185475 |
Claims
1. An image-transfer apparatus, comprising: a first transfer
mechanism configured to transfer an image onto a first surface of a
recording sheet; a second transfer mechanism configured to transfer
an image onto a second surface of the recording sheet; and a
controller configured to select one of: a first case, in which the
first transfer mechanism transfers a first original image onto the
first surface of the recording sheet, or a second case, in which
the second transfer mechanism transfers the first original image
onto the second surface of the recording sheet.
2. The image transfer apparatus of claim 1, wherein the controller
is further configured to select one of: a third case, in which the
first transfer mechanism transfers the first original image onto
the first surface of the recording sheet, and the second transfer
mechanism transfers a second original image onto the second surface
of the recording sheet, or a fourth case, in which the first
transfer mechanism transfers the second original image onto the
first surface of the recording sheet, and the second transfer
mechanism transfers the first original image onto the second
surface of the recording sheet.
3. An image forming apparatus, comprising: a first transfer
mechanism configured to transfer an image onto a first surface of a
recording sheet; a second transfer mechanism configured to transfer
an image onto a second surface of the recording sheet; and a
controller configured to select one of: a first case, in which the
first transfer mechanism transfers a first original image onto the
first surface of the recording sheet, or a second case, in which
the second transfer mechanism transfers the first original image
onto the second surface of the recording sheet.
4. The image forming apparatus of claim 3, further comprising: a
first sheet ejecting mechanism configured to eject the recording
sheet with the first surface oriented upward; and a second sheet
ejecting mechanism configured to eject the recording sheet with the
second surface oriented upward, wherein the controller is further
configured to select one of: the first case in which the first
transfer mechanism transfers the first original image onto the
first surface of the recording sheet, or the second case in which
the second transfer mechanism transfers the first original image
onto the second surface of the recording sheet, in accordance with
a condition as to which one of the first and second sheet ejecting
mechanisms is used to eject a recording sheet.
5. The image forming apparatus of claim 4, wherein the controller
is further configured to select one of: a third case, in which the
first transfer mechanism transfers the first original image onto
the first surface of the recording sheet, and the second transfer
mechanism transfers a second original image onto the second surface
of the recording sheet, or a fourth case, in which the first
transfer mechanism transfers the second original image onto the
first surface of the recording sheet, and the second transfer
mechanism transfers the first original image onto the second
surface of the recording sheet.
6. A method of transferring an image onto a recording sheet
comprising: selecting one of a first output tray and a second
output tray; when the first output tray is selected, transferring
an original image onto a first surface of a recording sheet via a
first transfer mechanism; and when the second output tray is
selected, transferring the original image onto a second surface of
the recording sheet via a second transfer mechanism.
7. A method of forming an image on a recording sheet comprising:
selecting one of a first output tray and a second output tray; when
the first output tray is selected, transferring an original image
onto a first surface of a recording sheet via a first transfer
mechanism; and when the second output tray is selected,
transferring the original image onto a second surface of the
recording sheet via a second transfer mechanism.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 09/915,398, filed Jul. 27, 2002, which claims priority to
Japanese Patent Application Nos. 2000-231576, filed on Jul. 31,
2000, 2000-231575, filed on Jul. 31, 2000, and 2001-185475, filed
on Jun. 19, 2001, the entire contents of each of which are hereby
incorporate by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to a method and
apparatus for image forming and more particularly, to a method and
apparatus for image forming, which is capable of effectively
collating a stack of single-sided or double-sided recording sheets
in increasing order of page numbers in a desired ejection tray.
[0004] 2. Discussion of Background
[0005] Some conventional image forming apparatuses, such as copying
machines, printers, facsimiles, and other similar devices, are
capable of performing a double-sided recording operation for
recording on both the first and second sides of a recording sheet.
Typically, in the double-sided recording operation of these
conventional machines, a first toner image is formed on the first
side of a recording sheet and a second toner image is formed on the
second side of the same recording sheet after the first toner image
is fixed. Before the second toner image is formed, the recording
sheet is reversed. After completion of the second image forming
operation, the second toner image is fixed and, as a result, a
double-sided recording is achieved.
[0006] Various problems may occur with the above-described
double-sided recording operation, such as difficulty in reversing
the recording sheet, unstable sheet transfer due to a paper curl
problem caused by the first fixing process, and other similar
problems.
[0007] On the other hand, each of Japanese Unexamined Patent
Application Publication Nos. 1-209470 (hereinafter "JP '470") and
10-142869 (hereinafter "JP '869") describes an image forming
apparatus which transfers toner images to both the first and second
sides of a recording sheet with two image carrying members and
fixes the toner images via an one time fixing process.
[0008] In the image forming apparatus of JP '470, a first toner
image is formed on a photoconductive member and is transferred onto
a transfer belt with a first transfer member. Then, a second toner
image is formed on the photoconductive member and is transferred
onto a first surface of a recording sheet with the first transfer
member. After that, the first toner image on the transfer belt is
transferred onto the second side of the recording sheet with a
second transfer member. Thereby, the first and second toner images
are transferred onto both the first and second sides of the
recording sheet and the recording sheet is then subjected to a
fixing process.
[0009] Japanese Unexamined Patent Application Publication No.
3-253881 (hereinafter "JP '881") describes an image forming
apparatus which is similar to the image forming apparatus of JP
'470. A difference between the two image forming apparatuses is
that the image forming apparatus of JP '881 eliminates the second
transfer member by reversing a polarity of the second toner image
on the photoconductive member before it is transferred to the
recording sheet. Thereby, the first and second toner images are
transferred onto both the first and second sides, respectively, of
the recording sheet without the second transfer member.
[0010] The image forming apparatus of JP '869 is provided with two
transfer members and performs an one time fixing operation for
fixing color images which have been transferred onto both the first
and second sides of a recording sheet with the first and second
transfer members, respectively. This image forming apparatus uses a
guide member, which includes a flat plate on which a plurality of
star-like wheels are rotatably mounted, to smoothly transfer the
double-sided recording sheet with the color images on both the
first and second sides thereof.
[0011] However, the image forming apparatuses, of JP '470, JP '869,
and JP '881, have a drawback with respect to the stack order of the
output recording sheets. For example, as shown in FIG. 1, a stack
of recording sheets are output face down in a tray T1, but are face
up in a tray T2. Therefore, the stack of recording sheets output to
the trays T1 and T2 are different in page number order.
[0012] Japanese Unexamined Patent Application Publication No.
2000-19799 (hereinafter "JP '799") describes an image forming
apparatus that includes a tray switching mechanism for switching
between face-down and face-up ejection trays. A sheet reverse
mechanism is used to make it possible to switch the ejection trays
without changing relationships between images and surfaces of a
recording sheet. A technique is also used in which the
relationships between images and surfaces of a recording sheet are
changed when the ejection trays are switched from one to the other
in an image forming apparatus having no sheet reverse
mechanism.
[0013] However, JP '799 has a drawback in that a thick sheet is not
properly transferred. This is because a recording sheet is bent
when it is reversed by the sheet reverse mechanism.
[0014] In a case where an image forming apparatus, having a
plurality of ejection trays as shown in FIG. 1, applies the
technique for changing the relationships between images and
surfaces of a recording sheet as described in JP '799, it is not
easy for a user to properly instruct the change of the
relationships between images and surfaces of a recording sheet.
[0015] Japanese Unexamined Patent Application Publication No.
2000-38234 (hereinafter "JP '234") describes an image forming
apparatus which reads images on both the first and second sides of
a double-sided original and records the read images on both the
first and second sides, respectively, of a recording sheet. In this
apparatus, the double-sided original is reversed after a completion
of reading the first side of the original and then, the second side
of the original is read. In the recording operation, the recording
sheet is reversed after the recording of a first image on a first
side of the recording sheet is completed and then, a second image
is recorded on the second side of the recording sheet.
[0016] Japanese Unexamined Patent Application Publication No.
11-258864 describes an image forming apparatus which reads images
on both the first and second sides of a double-sided original by
moving the original and then recording the read images on both the
first and second sides of a recording sheet via a one time sheet
transferring process.
[0017] However, the apparatuses which are capable of double-sided
reading and double-sided recording have the drawback that they do
not collate a stack of recording sheets, particularly when a
plurality of ejection trays are used, and this drawback is in
addition to the problems they have in common with conventional
apparatuses (i.e., low sheet transfer stability and larger machine
size).
SUMMARY OF THE INVENTION
[0018] The present invention provides a novel image forming
apparatus which avoids the drawbacks of the prior art. A first
example of an image forming apparatus includes first and second
image carrying members, a plurality of ejection trays, and a sheet
transferring mechanism. The first image carrying member carries
images in increasing order of corresponding sheet numbers. The
second image carrying member carries an image transferred from the
first image carrying member. The plurality of ejection trays
includes a first ejection tray configured to stack a plurality of
output sheets in a forward orientation and a second ejection tray
configured to stack a plurality of output sheets in a reversed
orientation. The sheet transferring mechanism transfers a recording
sheet to a nip formed between the first and second image carrying
members. In the image forming apparatus of the first example, the
first image carrying member transfers an image to a first surface
of the recording sheet and, at the same time, the second image
carrying member transfers a second image to a second surface of the
recording sheet in response to a selection between the first and
second ejection trays in a double-sided recording mode so that the
first and second ejection trays stack the plurality of recording
sheets in increasing page number order.
[0019] The image forming apparatus of the first example may further
include a mode selecting mechanism configured to select any one of
a single-sided recording mode and a double-sided recording
mode.
[0020] The image forming apparatus of the first example may further
include a tray selecting mechanism configured to select any one of
the first and second ejection trays.
[0021] The image forming apparatus of the first example may further
include a sheet selecting mechanism configured to select the type
of sheet to be used. In this case, any one of the first and second
ejection trays is selected in accordance with a selection made by
the sheet selecting mechanism.
[0022] The image forming apparatus of the first example may further
include a plurality of sheet supplying mechanisms each configured
to supply the recording sheets to the sheet transferring
mechanism.
[0023] The image forming apparatus of the first example may further
include a cassette selecting mechanism configured to select one of
the plurality of sheet supplying mechanisms.
[0024] The image forming apparatus of the first example may further
include a sheet selecting mechanism configured to select the type
of sheet to be used. In this case, one of the plurality of sheet
supplying mechanisms is selected in accordance with a selection
made by the sheet selecting mechanism.
[0025] The image forming apparatus of the first example may further
include an extra sheet supplying mechanism configured to insert a
recording sheet in an approximately forward orientation. In this
case, a recording sheet is transferred from the extra sheet
supplying mechanism to the first ejection tray via the sheet
transferring mechanism.
[0026] The image forming apparatus of the first example may further
include a sheet selecting mechanism configured to select the type
of sheet to be used. In this case, the extra sheet supplying
mechanism and the first ejection tray are selected when the sheet
selecting mechanism selects a thick sheet. The extra sheet
supplying mechanism may include a manual sheet insertion tray.
[0027] The image forming apparatus of the first example may further
include a sensor for detecting when the manual sheet insertion tray
is accessed by a user. In this case, the extra sheet supplying
mechanism and the first ejection tray are selected when the sensor
detects that the user accesses the manual sheet insertion tray.
[0028] The first image carrying member may transfer an image on
odd-numbered pages onto an upper surface of the recording sheet
and, at the same time, the second ejection tray transfers an image
on even-numbered pages onto a lower surface of the recording sheet
when the second ejection tray is selected in a double-sided
recording mode so that the second ejection tray stacks a plurality
of the recording sheets in increasing order of page numbers.
[0029] The first image carrying member may transfer a first image
onto a first surface of the recording sheet and the second image
carrying member may transfer a second image onto a second surface
of the recording sheet in response to a selection made by the tray
selecting mechanism between the first and second ejection
trays.
[0030] The mode selecting mechanism, the tray selecting mechanism,
the sheet selecting mechanism, and the cassette selecting mechanism
may be mounted on a control panel of the apparatus.
[0031] In the image forming apparatus of the first example,
selections of a single-sided recording mode and the double-sided
recording mode, the first and second ejection trays, and the type
of sheet to be used may be made from an external host system.
[0032] In the image forming apparatus of the first example, a
selection of the plurality of sheet supplying mechanisms may be
made from an external host system.
[0033] The first image carrying member may have a property of
photoconductivity and may carry a toner image made in accordance
with an electrophotographic method. The second image carrying
member may carry a toner image transferred from the first image
carrying member.
[0034] The present invention further provides a second example of
an image forming apparatus which includes an image reading
mechanism, an image forming mechanism, a plurality of ejection
trays, a plurality of sheet cassettes, and a sheet transferring
mechanism. The image reading mechanism is configured to read an
original. The image forming mechanism is configured to perform an
image recording operation including image forming, image carrying,
and image transferring processes. The sheet transferring mechanism
is configured to transfer a recording sheet from one of the
plurality of sheet cassettes to a nip formed between the first and
second image carrying members. In the image forming apparatus of
the second example, the image forming mechanism performs an image
recording operation in response to a selection of one of the
plurality of ejection trays in accordance with images from
originals read by the image reading mechanism either in
single-sided or double-sided recording modes so that the plurality
of ejection trays stack a stack of recording sheets in increasing
order of page numbers.
[0035] The image forming mechanism may form a toner image in
accordance with an electrophotographic method. In this case, the
image forming mechanism includes first and second image carrying
members. The first image carrying member is configured to form a
toner image and to carry it thereon in increasing order of page
numbers starting from a first page. The second image carrying
member is configured to carry the toner image transferred from the
first image carrying member. The first image carrying member
transfers the toner image to a first side of a recording sheet and
the second image carrying member transfers the toner image to a
second side of the recording sheet.
[0036] The plurality of ejection trays may include a first ejection
tray configured to stack a plurality of output sheets in a forward
orientation and a second ejection tray configured to stack a
plurality of output sheets in a reversed orientation.
[0037] The stack of recording sheets, stacked in increasing order
of page numbers, may be a stack of recording sheets recorded in the
single-sided recording mode or in the double-sided recording
mode.
[0038] The image reading mechanism may read an image on a side of a
single-sided original in a single-sided reading mode and images on
both the first and second sides of a double-sided original in a
double-sided reading mode.
[0039] The image forming mechanism may record images, in the
single-sided recording mode, and outputs, in increasing order of
page numbers, when the images are read in the double-sided reading
mode by the reading mechanism.
[0040] The image forming mechanism may record images, in the
double-sided recording mode, and outputs, in increasing order of
page numbers, when the images are read in the double-sided reading
mode by the reading mechanism.
[0041] The image reading mechanism may read images on both the
first and second sides of a double-sided original via a one time
sheet transferring process by moving the double-sided original.
[0042] The image reading mechanism may include a first image
reading unit, configured to read an image of an original by moving
the original, and a second image reading unit, configured to read
an image of an original by holding the original at a predetermined
position.
[0043] The second image reading unit may include a moving member
that moves under a contact glass and is used as a part of the first
image reading unit on the condition that the moving member is
stopped.
[0044] The second image reading unit may be usable when originals
are placed on a sheet tray of the first image reading unit.
[0045] The image reading mechanism may include a sheet reversing
mechanism and may read images on both the first and second sides of
an original.
[0046] The image reading mechanism may include a detector for
detecting when an image being read is white in color and cancels
reading the image when the image is detected as a blank white
page.
[0047] In the image forming apparatus of the second example, one of
the plurality of ejection trays may be formed in a space between
the image reading mechanism and the image forming mechanism.
[0048] The image reading mechanism may include a tray for ejecting
originals. In this case, the tray has a size within a projection
area of the apparatus.
[0049] In the image forming apparatus of the second example, a
recording sheet may be transferred in an approximately straight
line from a first sheet cassette of the plurality of sheet
cassettes to a first ejection tray of the plurality of ejection
trays, wherein the first sheet cassette of the plurality of sheet
cassettes may be a manual sheet inserting tray.
[0050] The image forming apparatus of the second example may
further include a control panel close to the image reading
mechanism. The control panel includes a selecting mechanism
configured to select either a single-sided recording mode or a
double-sided recording mode and a selecting mechanism configured to
select one of the plurality of ejection trays.
[0051] The image forming mechanism may form images in increasing
order of corresponding sheet numbers.
[0052] The image forming mechanism may form a plurality of images
in increasing order of page numbers when the image reading
mechanism reads the plurality of images in increasing order of page
numbers.
[0053] The first image carrying member may have a property of
photoconductivity and the second image carrying member may be a
belt-shaped intermediate transfer member having a surface
resistance in a range of from 10.sup.5.OMEGA. to
10.sup.12.OMEGA..
[0054] The image forming apparatus of the second example may
further include a fixing mechanism configured to fix images
attached on both the first and second sides of a recording sheet,
while the recording sheet is supported by the belt-shaped
intermediate transfer member.
[0055] The belt-shaped intermediate transfer member may be made of
a heat resistant material.
[0056] The image forming mechanism may perform the image recording
operation in accordance with image information sent from an
external host system. Either a single-sided recording mode or a
double-sided recording mode may be selected by the external host
system. One of the plurality of ejection trays may be selected by
the external host system.
[0057] The image forming apparatus of the second example may
further include an external ejection tray unit that includes a
connecting sheet path connected to a sheet path of the apparatus
for turning and ejecting a recording sheet sent from the image
forming mechanism into a first ejection tray of the plurality of
ejection trays. In this case, the external ejection tray unit
stacks a plurality of recording sheet in increasing order of page
numbers. The connecting sheet path may be arranged along an edge
portion of the first ejection tray of the plurality of ejection
trays.
[0058] The image forming apparatus of the second example may
further include a switching pawl configured to selectively switch
between sending a recording sheet to the first ejection tray of the
plurality of ejection trays and sending a recording sheet to the
external ejection tray unit.
[0059] The image forming apparatus of the second example may
further include another external ejection tray unit which includes
a connecting sheet path connected to a sheet path of the apparatus
for ejecting a recording sheet sent from the image forming
mechanism in an approximately straight manner into one of the
plurality of ejection trays. In this case, the external ejection
tray unit stacks a plurality of recording sheets in increasing
order of page numbers.
[0060] The present invention provides a method for image forming.
In a first example, an image forming method includes the steps of:
selecting either a single-sided or a double-sided recording mode;
choosing the stack to be either face-down or face-up; inputting a
plurality of images in increasing order of page numbers; performing
a double-sided recording operation, when the double-side recording
mode is selected, by forming first and second successive images in
increasing order of corresponding sheet numbers, transferring the
first and second successive images onto both the first and second
surfaces of a recording sheet, fixing the first and second
successive images attached on both the first and second surfaces,
respectively, of the recording sheet, and stacking the recording
sheet in an orientation in accordance with a choice chosen by the
choosing step; repeating the performing step until the images input
by the inputting step are recorded; executing a single-sided
recording operation, when the single-sided recording mode is
selected, by forming images in increasing order of corresponding
sheet numbers, transferring the image onto a first surface of a
recording sheet, fixing the image attached onto the first surface
of the recording sheet, and stacking the recording sheet in an
orientation in accordance with a choice chosen by the choosing
step; and repeating the executing step until the images input by
the inputting step are recorded.
[0061] The inputting step may read a plurality of originals and
generate data of a plurality of images.
BRIEF DESCRIPTION OF THE DRAWING
[0062] A more complete appreciation of the present invention and
many of the attendant advantages thereof will be readily obtained
as the same becomes better understood by reference to the following
detailed description when considered in connection with the
accompanying drawings, wherein:
[0063] FIG. 1 is a cross-sectional view of a conventional image
forming apparatus;
[0064] FIG. 2 is a cross-sectional view of a printer according to
an embodiment of the present invention;
[0065] FIG. 3 is a top plan view of a control panel of the printer
of FIG. 2;
[0066] FIG. 4 is a cross-sectional view of a color printer
according to the embodiment of the present invention;
[0067] FIG. 5 is a cross-sectional view of an image forming
apparatus, including the printer of FIG. 2, a scanner, and an
automatic document feeder or ADF;
[0068] FIG. 6 is a perspective view of the image forming apparatus
of FIG. 5;
[0069] FIG. 7 is a cross-sectional view of an image sensor included
in the automatic document feeder or ADF of FIG. 5;
[0070] FIG. 8 is a cross-sectional view of an image forming
apparatus of FIG. 5 without the Automatic document feeder or
ADF;
[0071] FIG. 9 is a table for explaining relationships between
various manners of image reading and various manners of image
forming performed by the image forming apparatuses of FIGS. 5 and
8;
[0072] FIG. 10 is a cross-sectional view of the image forming
apparatus of FIG. 5 with extra ejection trays;
[0073] FIG. 11 is a cross-sectional view of an image forming
apparatus including a modified printer, a modified scanner, and a
modified automatic document feeder or ADF according to another
embodiment of the present invention; and
[0074] FIG. 12 is a cross-sectional view of a color image forming
apparatus including the color printer of FIG. 4, the scanner of
FIG. 5, and the Automatic document feeder or ADF of FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0075] In describing preferred embodiments illustrated in the
drawings, specific terminology is employed for the sake of clarity.
However, the present invention is not intended to be limited to the
specific terminology so selected and it is to be understood that
each specific element includes all technical equivalents which
operate in a similar manner.
[0076] Referring now to the drawing, wherein like reference numeral
designate identical or corresponding parts throughout the several
views, FIG. 2 illustrates a printer 100 according to an embodiment
of the present invention. Like the printer shown in FIG. 1, the
printer 100 shown in FIG. 2 has a photoconductive drum 1 at its
approximate center, wherein the photoconductive drum 1 serves as a
first image carrying member. The printer 100 is further provided
with various components, which are located around the
photoconductive drum 1, including: a cleaning unit 2; a discharging
unit 3; a charging unit 4; and a development unit 5. An exposure
unit 7 is provided at a position above the photoconductive drum 1.
The exposure unit 7 emits a laser beam L in a predetermined
direction so as to be between the charging unit 4 and the
development unit 5 in order to impinge on the surface of the
photoconductive drum 1 at a writing position.
[0077] The photoconductive drum 1, the cleaning unit 2, the
discharging unit 3, the charging unit 4, and the development unit 5
are assembled into a single unit (hereinafter referred to as a
process cartridge) within the printer 100. The process cartridge
can be exchanged at any time when its contents are consumed and its
useful life is over.
[0078] The printer 100 is further provided with a belt unit 20
located at a position under the photoconductive drum 1. The belt
unit 20 includes an intermediate transfer belt 10, serving as a
second image carrying member, which contacts the photoconductive
drum 1. The intermediate transfer belt 10 extends, under pressure,
between rollers 11, 12, and 13 and the intermediate transfer belt
10 rotates in a counterclockwise direction. The intermediate
transfer belt 10 has electrical resistance properties so that toner
can be transferred thereto. The intermediate transfer belt 10 also
has heat resistance properties. In this example, the intermediate
transfer belt 10 has a surface resistance in a range of from
approximately 10.sup.5.OMEGA. to approximately
10.sup.12.OMEGA..
[0079] Rollers 14 and 15, cooling rollers 16, lower fixing roller
18, and first transfer mechanism 21 are provided inside of the
intermediate transfer belt 10. Rollers 14 and 15 help support the
intermediate transfer belt 10, while cooling rollers 16 cool the
intermediate transfer belt 10. The lower fixing roller 18 includes
a heat source, such as a heater, for fixing a toner image onto a
first surface of a recording sheet, after the toner image has been
transferred onto the first surface of the recording sheet. The
first transfer mechanism 21 is arranged at a position opposite of
the photoconductive drum 1, relative to the intermediate transfer
belt 10, so as to transfer a toner image, formed on the
photoconductive drum 1, onto the intermediate transfer belt 10 or a
first surface of a recording sheet.
[0080] A second transfer mechanism 22, a fixing unit 30, and a belt
cleaning unit 25 are arranged at various positions around the
intermediate transfer belt 10. The fixing unit 30 includes an upper
fixing roller 19 having a heat source, such as a heater, inside
thereof. The upper fixing roller 19 fixes a toner image onto the
second surface of the recording sheet, after the toner image has
been first transferred onto the second surface of a recording
sheet. The fixing unit 30 is held so as to be movable about a
fulcrum 30a. Thus, the fixing unit 30 can be tilted back and forth
in directions shown by double-sided arrow G with a mechanism (not
shown) so as to contact the lower fixing roller 18, under pressure,
and then move away from the lower fixing roller 18. Ventilation
inside of the printer 100 is performed by fan F1 which is provided
at a position to a left of and above the fixing unit 30.
[0081] The belt cleaning unit 25 is provided with a cleaning roller
25a, a cleaning blade 25b, a toner transfer mechanism 25c, and a
pivot shaft 25d located inside thereof so as to clean residual
toner off the surface of the intermediate transfer belt 10. The
residual toner accumulated in the belt cleaning unit 25 is
transferred with the toner transfer mechanism 25c to a toner
collection container (not shown). The belt cleaning unit 25 is
tilted about the pivot shaft 25d back and forth in directions shown
by double-sided arrow H with a mechanism (not shown) so as to
contact and move away from the intermediate transfer belt 10.
[0082] A sheet cassette 26, which contains a plurality of recording
sheets P, is provided at a lower part of the printer 100. The sheet
cassette 26 is configured so as to be insertable and removable from
the printer 100. As shown in FIG. 2, the sheet cassette 26 is
inserted by being pushed to the right and removed by being pulled
to the left. A sheet feeding roller 27 is provided at a position
close to and above the leading edge of the sheet cassette 26 in a
sheet transfer direction, i.e., towards the right in FIG. 2. A pair
of registration rollers 28 are arranged at a position to the right
of the photoconductive drum 1 and a guide member 29 is provided to
guide a recording sheet P to a transfer position from the
registration rollers 28. Above the sheet cassette 26, an electric
unit E1 and a control unit E2 are arranged. A manual sheet inlet
35, which includes a plate 37 on which a plurality of recording
sheets P may be placed, is provided on a right-hand side of the
printer 100 and a sheet feeding roller 36 is arranged at a position
such as to feed a recording sheet P placed on the plate 37. A
recording sheet P, inserted from the manual sheet inlet 35, is
guided to the registration rollers 28 by the guide member 29.
[0083] A switching pawl 42 is provided at a position to the left of
the fixing unit 30. The switching pawl 42 is turned about a pivot
43 with an actuator (not shown), such as a solenoid, to switch a
transfer direction of the recording sheet P sent from the belt unit
20 to a stacking portion 40 formed on the upper surface of the
printer 100 or to an ejection tray 44 provided at a left-hand side
of the printer 100. The recording sheet P is sent to the stacker 40
when the switching pawl 42 is set at a position, as shown in FIG.
2, and is sent to the ejection tray 44 when the switching pawl 42
is turned in the direction of arrow J.
[0084] A pair of transfer rollers 33, for transferring the
recording sheet P, are provided above the switching pawl 42 and a
pair of ejection rollers 34, for ejecting the recording sheet P to
the stacker 40, are provided above the transfer rollers 33. Guide
members 31a and 31b are arranged between the transfer rollers 33
and the ejection rollers 34. A pair of ejection rollers 32, for
ejecting the recording sheet P to the ejection tray 44, are
arranged at a position to the left of the switching pawl 42.
[0085] The printer 100 of FIG. 2, which is structured in the
above-described way, performs an image forming operation in which
images are recorded on both the first and second surfaces of a
recording sheet P, in the following manner. In this discussion, an
image to be formed first is referred to as a first image and an
image to be formed second is referred to as a second image.
Further, a surface of the recording sheet P, on which a first image
is printed, is referred to as a first surface of the recording
sheet P and the second surface, on which a second image is printed,
is referred to as a second surface of the recording sheet P.
[0086] The printer 100 receives signals from an external host
system (not shown), such as a computer, and forms images with the
exposure unit 7 in accordance with the signals. Light, from a laser
light source of the exposure unit 7, is continuously reflected by a
motor-driven rotary polygonal mirror 7a and, via mirrors 7b and
lens 7c, impinges on the charged surface of the photoconductive
drum 1. Thereby, an electrostatic latent image is formed on the
photoconductive drum 1 in accordance with the received signals.
[0087] The above electrostatic latent image is developed with toner
by the development unit 5 into a visual toner image and is held on
the photoconductive drum 1. For the sake of convenience, this toner
image is referred to as the first toner image. The first toner
image is then transferred by an action of the first transfer
mechanism 21 onto the intermediate transfer belt 10 which is
rotated in synchronism with the photoconductive drum 1. After the
transfer process, the toner, remaining on the surface of the
photoconductive drum 1, is removed by the cleaning unit 2 and the
charge thereon is discharged by the discharging unit 3. The
photoconductive drum 1 is thus prepared for a next job cycle of
image forming.
[0088] The intermediate transfer belt 10 is rotated
counterclockwise, as shown in FIG. 2, while carrying the first
toner image which is to be transferred onto a first surface of the
recording sheet P. During this process, the second transfer
mechanism 22, the fixing unit 30, and the belt cleaning unit 25 are
controlled so as to be kept in an inoperable position. In other
words, electric inputs are cut off from the second transfer
mechanism 22, the fixing unit 30, and the belt cleaning unit 25 or
else, these components are moved away from the intermediate
transfer belt 10.
[0089] A process for forming a second toner image, in a similar
manner to that described above on the photoconductive drum 1, is
started when the intermediate transfer belt 10, which carries the
first toner image, is advanced to a predetermined position. At the
same time, the recording sheet P starts to be transferred from the
sheet cassette 26 or from the manual sheet inlet 35. When the sheet
feeding roller 27 or 36 is rotated in either a counterclockwise
direction or a clockwise direction, respectively, as shown by the
arrows in FIG. 2, an uppermost recording sheet P is transferred
towards the registration rollers 28.
[0090] As the intermediate transfer belt 10, which is moved in
synchronism with the photoconductive drum 1, rotates, the first
toner image, carried on the intermediate transfer belt 10, is
advanced to a position where the intermediate transfer belt 10
contacts the photoconductive drum 1.
[0091] The recording sheet P is advanced by the registration
rollers 28 to a contact position between the photoconductive drum 1
and the intermediate transfer belt 10 such that the second surface
of the recording sheet P contacts the surface of the
photoconductive drum 1. Then, the second toner image, which is
formed on the photoconductive drum 1, is transferred onto the
second surface of the recording sheet P by the first transfer
mechanism 21. During this process, the recording sheet P is
transferred by the registration rollers 28 such that the second
toner image is transferred onto a proper position on the second
surface of the recording sheet P.
[0092] During a time when the second toner image is transferred
from the photoconductive drum 1 to the second surface of the
recording sheet, the first surface of the recording sheet P
contacts the surface of the intermediate transfer belt 10 on which
the first toner image is carried. When the recording sheet P passes
through a transfer region of the second transfer mechanism 22, a
voltage is applied to the second transfer mechanism so that the
first toner image is transferred onto the first surface of the
recording sheet P.
[0093] Thus, the first and second images are attached to the first
and second surfaces, respectively, of the recording sheet P. The
recording sheet P is further transported to a fixing region of the
fixing unit 30 by the intermediate transfer belt 10. The fixing
unit 30 moves slightly downwardly so that the upper fixing roller
19 is pressed into contact with the lower fixing roller 18 and the
intermediate transfer belt 10 is held therebetween. Thereby, the
first and second toner images are fixed to the first and second
surfaces, respectively, at the same time. After the transfer
process, the recording sheet P is kept in contact with the
intermediate transfer belt 10 so that the toner images can be kept
in a desirably fixed state, without wobbling.
[0094] After the fixing process, the recording sheet P is separated
from the intermediate transfer belt 10 at the roller 11 due to a
relationship between a stiffness of the recording sheet P and a
curvature of the roller 11. The recording sheet P is further
transferred to either the stacker 40 or the ejection tray 44
depending upon the position of the switching pawl 42.
[0095] When the recording sheet P is output to the stacker 40, the
first surface of the recording sheet P faces down in the stacker
40. Therefore, when stacking in increasing page number order is
desired, the second toner image needs to be generated first and
retained on the intermediate transfer belt 10 and the first toner
image needs to be generated after the second toner image and then,
transferred onto the recording sheet P directly from the
photoconductive drum 1. In other words, the first toner image is to
be recorded on the second page and the second toner image is to be
recorded on the first page of the recording sheet P. For the third
page and onwards, this sequential order needs to be maintained in
the same manner. That is, when an even page number has an image
thereon, this image is first generated and preserved on the
intermediate transfer belt 10 and an image, on the following odd
page number, is then generated so as to be transferred from the
photoconductive drum 1 to the recording sheet P. In this case, the
sequential order of the page numbers of the image forming operation
is as follows:
[0096] 2.fwdarw.1.fwdarw.4.fwdarw.3.fwdarw.6.fwdarw.5.fwdarw. . .
.
In addition, the output order of the sheet numbers of the recording
sheets P is as follows:
[0097] 1st sheet.fwdarw.2nd sheet.fwdarw.3rd sheet.fwdarw. . .
.
[0098] That is, the image forming operation is performed in
increasing order of sheet numbers. For example, the first and
second pages are recorded on the first sheet, the third and fourth
pages are recorded on the second sheet, the fifth and sixth pages
are recorded on the third sheet, and so on.
[0099] Some other image forming apparatuses perform the image
forming in a reverse order, i.e., images of the last page and the
page before the last page are recorded on the sheet which is output
first. This sheet may be referred to as the first sheet in relation
to these apparatuses. However, in the printer 100, the first sheet
in a double-sided recording operation is defined as a sheet on
which images of the first and second pages are recorded, but not as
a sheet which is first output. In a single-sided recording
operation, the first sheet is defined as a sheet on which the first
page is recorded. The term double-sided recording operation means a
recording mode in which recording is performed on both the first
and second sides of a recording sheet. The term single-sided
recording operation means a recording mode in which recording is
preformed on a single side of a recording sheet.
[0100] When the recording sheet P is ejected to the ejection tray
44, the second surface, which has the second toner image from the
photoconductive drum 1, faces upwardly. Therefore, when stacking in
increasing page number order is desired in the ejection tray 44,
the first toner image needs to be generated first and retained on
the intermediate transfer belt 10 and then, the second toner image
needs to generated afterwards and transferred onto the recording
sheet P directly from the photoconductive drum 1. It must be
arranged that the first toner image is recorded on the first page
and the second toner image is recorded on the second page of the
recording sheet P. This sequential order is maintained in the same
manner for the third page and onwards. That is, when an
odd-numbered page has an image thereon, this image is generated
first and preserved on the intermediate transfer belt 10 and an
image of the following even-numbered page is then generated
afterwards so as to be transferred from the photoconductive drum 1
to the recording sheet P. In this case, the sequential order of the
page numbers of the image forming is as follows:
[0101] 1.fwdarw.2.fwdarw.3.fwdarw.4.fwdarw.5.fwdarw.6.fwdarw. . .
.
In addition, an output order of the sheet numbers of the recording
sheets P is as follows:
[0102] 1st sheet.fwdarw.2nd sheet.fwdarw.3rd sheet.fwdarw. . .
.
That is, the image forming is performed in increasing order of
sheet numbers, as is the case with the stacking in the stacker
40.
[0103] In either case of stacking in the stacker 40 or in the
ejection tray 44, the image forming operation is performed in
increasing order of sheet numbers so that the user can easily find
any sheet. In many cases, the user may instantly check if the image
forming operation is being performed in a manner desired by the
user by particularly reviewing the first page or the first few
pages. When the image forming operation is performed in decreasing
order of sheet numbers, i.e., the last sheet having the last page
is output first, the user needs to wait until the first sheet
having the first page thereon is output.
[0104] In addition, when an image forming operation is performed in
increasing order of sheet numbers, the handling of the sheets is
facilitated when a paper jam occurs in the printer 100. After
eliminating the conditions leading to the paper jam, the user
simply needs to instruct the printer 100 to start the image forming
operation from the page including the jammed sheet. This kind of
paper jam handling would help the user, particularly, when the
printer 100 is in a mode in which the process of eliminating an
error condition by the paper jam is not automated and the user is
required to cope with the problem.
[0105] In the printer 100, during a double-sided recording mode,
the user can select either the stacker 40 or the ejection tray 44
via a control panel 50 (to be explained in more detail below), as
shown in FIG. 3. During a double-side recording mode, when the user
selects either one of the stacker 40 and the ejection tray 44, the
image forming operation is controlled so as to be performed in the
above-described sequence and thus, the recording sheets P are
ejected to the designated place in increasing order of sheet
numbers. Controlling the order of the image forming operation,
according to the order of sheet numbers, is performed by a control
unit (not shown).
[0106] Accordingly, the user simply needs to select one of the
stacker 40 and the ejection tray 44 without paying attention to a
relationship between the order of sheet numbers and the order of
the image forming operation. Thus, the printer 100 can perform the
double-sided recording operation without requiring the user to
perform complex tasks. The order of the image forming operation can
be switched from one to another with a known technique associated
with storage of image data into a memory.
[0107] In the printer 100, when the recording sheet P is
transferred from the manual sheet inlet 35 to the ejection tray 44,
the recording sheet P passes through the printer 100 in an
approximately straight manner. Therefore, a thick sheet, such as a
thick paper sheet, an overhead-projector sheet, etc., is preferably
inserted into the manual sheet inlet 35 and is ejected to the
ejection tray 44 through an approximately straight passage. Thus,
the thick sheets can be processed in the double-sided recording
mode and be output in the appropriate page number order, without
causing problems of being too thick while passing through the
printer 100.
[0108] As for a standard sheet, it can be sent from either the
sheet cassette 26 or the manual sheet inlet 35 and be ejected to
either the stacker 40 or the ejection tray 44. In this case, the
sheets can be output in the double-sided recording mode in the
appropriate page number order. This sequence may be set as a
default since the standard sheet is normally a frequently used
sheet.
[0109] In a typical image forming operation, a mirror image is
formed on the photoconductive drum 1 and is directly transferred
onto the recording sheet P, thereby turning into a normal image.
However, when the intermediate transfer belt 10 is involved, that
is, the mirror image on the photoconductive drum 1 is transferred
to the intermediate transfer belt 10 and is transferred to the
recording sheet P, the mirror image is formed on the recording
sheet P. Therefore, a normal image is formed on the photoconductive
drum 1 for the first surface of the recording sheet P and a mirror
image is formed on the photoconductive drum 1 for the second
surface of the recording sheet P. This image alternation in a
normal or mirror mode can be performed by controlling the exposure
unit 7 using a known image processing technique.
[0110] The belt cleaning unit 25, separated away from the
intermediate transfer belt 10, is turned after the toner image is
transferred onto the recording sheet P from the intermediate
transfer belt 10 such that the cleaning roller 25a contacts the
intermediate transfer belt 10. Thereby, the residual toner is
removed from the intermediate transfer belt 10 and onto the
cleaning roller 25a and is then scraped off the cleaning roller 25a
by the cleaning blade 25b. The scraped toner is collected by the
toner return mechanism 25c to the toner collection container (not
shown). The residual toner, after having heat applied thereto by
the lower and upper fixing rollers 18 and 19, is prone to be
removed from the intermediate transfer belt 10 before it is cooled.
Therefore, the belt cleaning unit 25 is preferably arranged
upstream from the cooling rollers 16.
[0111] After the cleaning process, the intermediate transfer belt
10 passes through the cooling region where the cooling rollers 16
cool the intermediate transfer belt 10. As an alternative to the
cooling rollers 16, a heat pipe may be arranged to contact the
inside surface of the intermediate transfer belt 10 or an
application of an air flow to the intermediate transfer belt 10,
after the fixing process, may also be effective.
[0112] Next, procedures of the single-sided recording operation in
the printer 100 will be explained. The procedure of a single-sided
recording operation in which the stacker 40 is used is different
from the procedure of a single-sided recording operation in which
the ejection tray 44 is used. When the recording sheets P are
output into the stacker 40, the process of transferring the toner
image onto the intermediate transfer belt 10 is eliminated and the
toner image formed on the photoconductive drum 1 is directly
transferred onto the recording sheet P. In this case, the toner
image on the photoconductive drum 1 is a mirror image and is
transferred onto the recording sheet P in the form of a normal
image.
[0113] In FIG. 2, the recording sheet P is fed to the contact
position between the photoconductive drum 1 and the intermediate
transfer belt 10 in synchronism with the movement of the toner
image on the photoconductive drum 1 and the toner image is
transferred onto the upper surface of the recording sheet P facing
the photoconductive drum 1 by the action of the first transfer
mechanism 21.
[0114] In this procedure, the second transfer mechanism 22 is not
operated. The recording sheet P is moved with the intermediate
transfer belt 10 and the toner image is fixed on the recording
sheet P through the fixing unit 30. After that, the recording sheet
P is separated away from the intermediate transfer belt 10 and is
lifted upwardly along the switching pawl 42, the guide members 31a
and 31b, the transfer rollers 33, and the ejection rollers 34.
Then, the recording sheet P is ejected in the direction of arrow A1
so as to be ejected face down in the stacker 40. As a result, a
plurality of the recording sheets P are stacked face down in
increasing order of sheet numbers. That is, although the image
forming is performed in increasing order of page numbers from the
first page, the user can have the plurality of the recording sheet
P in increasing order of page numbers with the first page on the
top of the stack when removing the stack of the recording sheets P
from the stacker 40. With this configuration, the sequential order
of the page numbers the image forming operation is as follows:
[0115] 1.fwdarw.2.fwdarw.3.fwdarw.4.fwdarw.5.fwdarw.6.fwdarw. . .
.
In addition, the output order of the sheet numbers of the recording
sheets P in this case is as follows:
[0116] 1st sheet.fwdarw.2nd sheet.fwdarw.3rd sheet.fwdarw. . .
.
[0117] When the ejection tray 44 is used to stack the recording
sheets P, the toner image, formed on the photoconductive drum 1, is
transferred onto the intermediate transfer belt 10 with the first
transfer mechanism 21 and is turned with the rotation of the
intermediate transfer belt 10. The recording sheet P is fed to the
contact position, between the photoconductive drum 1 and the
intermediate transfer belt 10, in synchronism with the movement of
the toner image on the intermediate transfer belt 10. Then, the
toner image, on the intermediate transfer belt 10, is transferred
onto the lower surface of the recording sheet P by the second
transfer mechanism 22. After that, the recording sheet P is
separated away from the intermediate transfer belt 10 and is
straightly transferred via the switching pawl 42 in the direction
of the arrow A2 so as to be ejected face down in the ejection tray
44. As a result, a plurality of the recording sheets P are stacked
face down in increasing order of page numbers. That is, although
the image forming operation is performed in increasing order of
page numbers starting with the first page, the user can have the
plurality of recording sheets P in increasing order of page numbers
starting with the first page on the top of the stack when removing
the stack of the recording sheets P from the ejection tray 44. With
this configuration, the sequential order of the page numbers of the
image forming operation is as follows:
[0118] 1.fwdarw.2.fwdarw.3.fwdarw.4.fwdarw.5.fwdarw.6.fwdarw. . .
.
In addition, the output order of the sheet numbers of the recording
sheets P is as follows:
[0119] 1st sheet.fwdarw.2nd sheet.fwdarw.3rd sheet.fwdarw. . .
.
[0120] As described above, in the single-sided recording operation,
the same order of the page numbers in the image forming operation
is applied to both cases of using the stacker 40 and the ejection
tray 44 and the only difference between the two cases is that the
toner image is transferred onto the upper surface or the lower
surface of the recording sheet P.
[0121] In the printer 100, when using the single-sided recording
mode, the user can select either the stacker 40 or the ejection
tray 44 via the control panel 50 (to be explained in more detail
below), as shown in FIG. 3. When using the single-sided recording
mode, the user may select either one of the stacker 40 and the
ejection tray 44, and then, the image forming operation is
controlled to be performed in the above-described sequence so that
the recording sheets P are ejected to the designated place in
increasing order of sheet numbers. Accordingly, the user simply
needs to select one of the stacker 40 and the ejection tray 44
without paying attention to a relationship between the order of
sheet numbers and the order of the image forming operation. Thus,
the printer 100 can perform the double-sided recording operation
without requiring the user to perform any complex tasks.
[0122] In the single-sided recording mode, a thick sheet, such as a
thick paper sheet, an overhead-projector sheet, etc., is preferably
inserted in the manual sheet inlet 35 and is ejected to the
ejection tray 44 through a fairly straight passage in the
approximate middle of the image forming apparatus or printer 100.
Thus, the thick sheets can also be processed in a single-sided
recording operation and be output in the appropriate page number
order, without causing problems in being run through the passage in
the approximate middle of the image forming apparatus or printer
100.
[0123] As described above, in the printer 100, the recording sheets
P are output in an increasing order of sheet numbers, such as the
first page, the second page, the third page, and so on, in both the
cases of a single-sided recording operation and a double-sided
recording operation, regardless of whether the stacker 40 or the
ejection tray 44 is selected. Therefore, in both cases, the user
can easily check if the image forming operation is performed in a
desired manner. In addition, in both cases of single-sided and
double-sided recording operations, the user can easily instruct the
printer 100 to restart the image forming operation upon the
occurrence of an error, such as a paper jam.
[0124] FIG. 3 shows the control panel 50 provided on the printer
100. As shown in FIG. 3, the control panel 50 includes a liquid
crystal display or LCD 51 and various function buttons. Among the
various function buttons, an online button 52 switches the printer
100 between being in an online condition and an offline condition.
A reset button 53 resets present conditions to default conditions.
A sheet selection button 54 designates the type of recording sheet
P to be used. For example, when an extraordinary type of sheet,
such as a thick sheet is used, the sheet selection button 54 is
pressed to allow selection of such sheet. A double-sided recording
button 55 makes the double-sided recording mode effective. An input
enabling button 56 enables various inputs. By pressing the input
enabling button 56, various items can be displayed on the LCD 51.
To find and select a desired item, an up-scrolling button 58, being
a black triangular mark, scrolls the items displayed on the LCD 51
upwardly and a down-scrolling button 59, being a black triangular
mark in a reversed direction from the above-described black
triangular mark of the up-scrolling button 58, scrolls the items
downwardly. An execution button 57 executes the designation of the
selected item. The input enabling button 56 allows for the
selection of the sheet feed unit (i.e., the sheet cassette 26 or
the manual sheet inlet 35) and the selection of the output tray
(i.e., the stacker 40 or the ejection tray 44).
[0125] In the printer 100, the double-sided recording mode is
selected by a press of the double-sided recording button 55. During
this selection, selection of the sheet cassette 26 and the manual
sheet inlet 35 and selection of the stacker 40 and the ejection
tray 44 can be performed with the input enabling button 56. This
selection may also be performed in a combination of the sheet feed
unit and the output tray. In the single-sided recording mode,
selections of the sheet feed unit and the output tray are
allowed.
[0126] With the above-described structure, the printer 100 can feed
the recording sheets P from the designated sheet feed unit and
output the recording sheets P to the designated output tray in an
appropriate page number order in both the single-sided recording
operation and the double-sided recording operation by properly
designating the sheet feed unit and the output tray. Thus, the user
can obtain the outputs in the page number order without paying
attention to the order of the image forming operation relative to
the sheet order.
[0127] As described above, when a thick sheet, such as a thick
paper sheet, an overhead projector or OHP sheet, and so on, is
used, such a sheet is preferably inserted from the manual sheet
inlet 35 and is ejected to the ejection tray 44 so as to run along
a straight passage in the approximate center of the printer 100. In
the printer 100, the manual sheet inlet 35 and the ejection tray 44
are automatically selected when a thick sheet is selected with the
sheet selection button 54. Accordingly, when the user desires
outputs in increasing page number order using a thick sheet in
either the single-sided recording mode or the double-sided
recording mode, the user needs to select the thick sheet using the
sheet selection button 54 without paying attention to the
selections of the sheet feed unit and the output tray and to the
order of the image forming operation relative to the sheet
numbers.
[0128] In the printer 100, the stacker 40 is designated as a
regular sheet feed unit in both the single-sided recording mode and
the double-side recording mode when a regular sheet is selected to
be used so that the recording sheets P are stacked in an
appropriate increasing page number order in the stacker 40 where
the user can easily take out the stack of the recording sheets
P.
[0129] In this way, the output tray is automatically designated in
accordance with the selection of the sheet type and the order of
the image forming operation is controlled such that the recording
sheets P are ejected to the designated output tray in the
increasing page number order. Thus, the user can obtain the stack
of the recording sheets P in the increasing page number order by
simply selecting the type of the recording sheet P.
[0130] As shown in FIG. 2, the printer 100 is provided with a
sensor 38 at a position inside of the printer 100 and close to the
manual sheet inlet 35. The sensor 38 detects a condition of whether
the manual sheet inlet 35 is closed or open. When the sensor 38
detects that the manual sheet inlet 35 is open, the printer 100
automatically selects the thick sheet mode and the ejection tray
44.
[0131] With this configuration, when the user decides to use
recording sheets P that are thick, the user can simply place the
thick recording sheets P at the manual sheet inlet 35 by first
opening the manual sheet inlet 35 to reveal the plate 37 and then
set the thick recording sheets P on the plate 37. Thus, after an
image forming operation has been performed and a stack of recording
sheets P, in an appropriate increasing page number order in the
ejection tray 44, is obtained in both the single-sided recording
mode or the double-sided recording mode.
[0132] In the printer 100, the switching of the sheet ejection
passage is achieved by a simple mechanism using a single component,
such as a switching pawl 42, which was described above.
[0133] In addition, the printer 100 allows the selections of
various operating conditions from an external host system connected
to the printer 100 as well as through the control panel 50, as was
described with respect to FIG. 3 above. Accordingly, the user of
the external host system can remotely select the sheet feed unit,
the output tray, the sheet type, and so on.
[0134] Next, a color printer 100B, according to the embodiment of
the present invention, will be explained with reference to FIG. 4.
The color printer 100B is similar to the printer 100 of FIG. 2,
except for a revolver type development unit 5R and a mechanism for
moving the intermediate transfer belt 10 away from the
photoconductive drum 1. Components having the same functions as
those in the printer 100, shown in FIG. 2, are labeled with the
same reference characters and will not be explained again, the
following discussion being focused on the difference between the
two printers.
[0135] As shown in FIG. 4, the revolver type development unit 5R is
rotatable and includes development stations 5a-5d. The revolver
type development unit 5R is rotated so as to switch the development
stations 5a-5d from one to another so as to be located at a
particular development position. The development stations 5a-5d
contain color toners that enable a full color development. For
example, the development stations 5a, 5b, 5c, and 5d contain
yellow, magenta, cyan, and black toner, respectively. To form a
mono-chrome toner image, the development station 5d is moved so as
to be located at the development position and the image forming
operation in the increasing page number order is performed in a
manner similar to that performed by the printer 100 of FIG. 2.
[0136] To form a full color image, the exposure unit 7 is caused to
generate light information to be developed with the yellow toner
and to scan the charged surface of the photoconductive drum 1 with
the light information so as to form an electrostatic latent image,
while the intermediate transfer belt 10 is moved away and separated
from the photoconductive drum 1. The development station 5a is
moved to the development position and is activated to develop the
electrostatic latent image with the yellow toner. Likewise, a
magenta toner image is formed on the photoconductive drum 1
overlaying the yellow toner image. After that, a cyan toner image
is generated to further overlay the yellow and the magenta toner
images. Finally, a black toner image is formed and overlays all
three of the yellow, magenta, and cyan toner images on the
photoconductive drum 1. Thereby, a four color toner image is formed
on the surface of the photoconductive drum 1 which is rotated four
times during the generation of the four color toner image.
[0137] After a completion of the four color toner image, the
intermediate transfer belt 10 is moved into contact with the
photoconductive drum 1. At the same time, the recording sheet P is
transferred, in synchronism with the movement of the four color
toner image, to the contact position between the photoconductive
drum 1 and the intermediate transfer belt 10. The four color toner
image is then transferred onto the recording sheet P by the action
of the first transfer mechanism 21.
[0138] In the double-sided recording mode, the intermediate
transfer belt 10 is moved into contact with the photoconductive
drum 1 when the first toner image is formed on the photoconductive
drum 1 so that the first toner image is transferred onto the
intermediate transfer belt 10 by the first transfer mechanism 21.
The intermediate transfer belt 10 is then moved away and separated
from the photoconductive drum 1 and is brought into a standby mode.
After that, the second toner image, i.e., the second four color
toner image, is formed on the photoconductive drum 1. When the
second toner image is formed on the photoconductive drum 1, the
intermediate transfer belt 10 is controlled in such a manner that
the leading edge of the second toner image on the photoconductive
drum 1 meets the leading edge of the first toner image on the
intermediate transfer belt 10. The intermediate transfer belt 10 is
moved into contact with the photoconductive drum 1 and the
recording sheet P is fed to the contact position between the
photoconductive drum 1 and the intermediate transfer belt 10 in
synchronism with the movement of the second toner image on the
photoconductive drum 1. The second toner image on the
photoconductive drum 1 is transferred onto the second surface of
the recording sheet P by the action of the first transfer mechanism
21 and the first toner image on the intermediate transfer belt 10
is transferred onto the first surface of the recording sheet P by
the action of the second transfer mechanism 22. Thus, the first and
second toner images are transferred onto the first and second
surfaces of the recording sheet P. The recording sheet P is further
transported, while in close contact with the intermediate transfer
belt 10, to the fixing unit 30. In both single-sided and
double-sided recording modes, processes occurring after the
recording sheet P has been transferred to the fixing unit 30 are
similar to those described in the operation of the printer 100 as
shown in FIG. 2.
[0139] As in the case of the printer 100 of FIG. 2, the toner image
generations are executed in an increasing order of page numbers and
the recording sheets P are output in an increasing order of sheet
numbers in both single-sided and double-sided recording modes in
the color printer 100B, regardless of which output tray is
selected. Therefore, the user can easily check whether the images
are generated in a desired form and can easily handle the error
conditions caused by, for instance, a paper jam.
[0140] As an alternative to the revolving type development unit 5R,
the color printer 100B may include a tandem type development unit
while performing the same function as described above. In this
case, a photoconductive belt is used in place of the
photoconductive drum 1 and a plurality of development stations
included in the tandem type development unit are arranged along the
photoconductive belt.
[0141] Next, an image forming apparatus, according to the present
invention, is explained with reference to FIGS. 5-7. The image
forming apparatus of FIG. 5 includes the printer 100 of FIG. 2 and
a scanner 200. The scanner 200 is provided on the top thereof with
an automatic document feeder or ADF 250, as shown in FIG. 5. The
automatic document feeder or ADF 250 automatically feeds a
sheet-formed original S which is placed on the automatic document
feeder or ADF 250. The image forming apparatus of FIG. 5 can
perform various functions including, copying the image of an
original, transmitting the image of the original through a
facsimile procedure, outputting data on a sheet in accordance with
signals sent from an external computer, and so on.
[0142] FIG. 6 shows an external view of the image forming apparatus
of FIG. 5. As shown in FIG. 6, the sheet cassette 26 is capable of
being pulled out in a direction indicated by an arrow C. An upper
part of the printer 100 serves as the stacker 40.
[0143] The scanner 200 is capable of performing either one of: a
sheet scanning, in which an original is read, while being moved;
and a book scanning, in which an original is read by a moving
member. In the scanner 200, contact glasses 62 and 63 are arranged
on an upper part of a frame 61. The contact glass 62 has a greater
surface area than that of the contact glass 63 and the contact
glass 62 is used as a plate on which an original is placed and read
during a book scanning mode. The contact glass 63 is used when an
original is read, as it is transferred by the automatic document
feeder or ADF 250 in the sheet scanning mode.
[0144] Inside the scanner 200, a first moving member 65, which
includes a light source 64 and mirrors, and a second moving member
66, which includes mirrors, are arranged so as to slide parallel to
the contact glass 62. The scanner 200 employs a known optical
system in which the first moving member 65 is moved at one half of
the speed of the second moving member 66. In the book scanning
mode, an original is read while the first and second moving members
65 and 66 are moved. In the sheet scanning mode, the first and
second moving members 65 and 66 are stopped at positions, as shown
in FIG. 5, and the original is read at a position of the contact
glass 63 as the original is moved relative to the contact glass
63.
[0145] In both sheet and book scanning modes, an original is
irradiated with light of the light source 64 and an image of the
original is focused on a fixed lens 67 and is captured by a
charge-coupled device or CCD 68, which then converts the captured
light information into an analog signal. Based on this analog
signal, digital image data is generated. After that, the digital
image data is subjected to various kinds of signal processing so as
to be used as facsimile information, print information to be
printed on an image forming apparatus, such as the printer 100,
image information to be edited by a computer, and so on.
[0146] The automatic document feeder or ADF 250 includes a sheet
bed 71, on which a stack of originals to be read, are placed. The
sheet bed 71 is provided with a moving plate 72. As shown in FIG.
5, a sheet transfer mechanism 73 of the automatic document feeder
or ADF 250 is formed in a left side portion of the sheet bed 71.
The sheet transfer mechanism 73 is provided with a sheet feeding
roller 74 arranged at an upper surface of the moving plate 72, a
pair of separation rollers 75, a pair of transfer rollers 76, an
image sensor 78, a transfer roller 77 arranged at a position facing
the image sensor 78, a sheet pressure plate 79, a transfer roller
80, and a pair of ejection rollers 81. Under the sheet bed 71, an
ejection tray 82 is arranged and a space, between the sheet bed 71
and the ejection tray 82, is used as an ejection space. A pressure
plate 70 is arranged under the ejection tray 82 and holds an
original, placed on the contact glass 62, under pressure. A bottom
surface of the pressure plate 70 is adhered with a white sheet 69.
The upper portion of the automatic document feeder or ADF 250,
including the pressure plate 70, is tilted upwardly so that the
contact glasses 62 and 63 are exposed. The pressure plate 70 is
configured to press a thick original such as a book. It is
convenient to use the automatic document feeder or ADF 250 when
originals are of sheet type. The automatic document feeder or ADF
250 is detachably mounted on the image forming apparatus.
[0147] A stack of sheet originals are placed on the moving plate 72
of the sheet bed 71 with the first page facing upwardly. The sheet
feed roller 74 is rotated in a direction indicated by an arrow
(i.e., clockwise in FIG. 5) so that the uppermost sheet in the
stack of originals is transferred to the sheet transfer mechanism
73. The pair of separation rollers 75 feed the originals sheet by
sheet. The original, fed from the moving plate 72, is transferred
through a sheet path, via the transfer rollers 76, 77, and 80, to
the ejection rollers 81, and is ejected in a direction B.
Therefore, the original is stacked in the ejection tray 82 with the
first page facing downwardly.
[0148] During the above process, the original passes by the image
sensor 78 with the second surface facing a reading part of the
image sensor 78 so that the image sensor 78 reads the second page.
After passing by the image sensor 78, the original passes through a
space between the sheet pressure plate 79 and the contact glass 63
with the first surface facing the contact glass 63 so that the
scanner 200 reads the first page of the original. When the scanner
200 reads an original passing by the contact glass 63, the first
and second moving members 65 and 66 are stopped at the reading
position under the contact glass 63.
[0149] Thus, when the automatic document feeder or ADF 250 is used,
the first and second surfaces of an original are read at two
different positions during a time of sheet transfer. Hereinafter, a
reading mechanism, that reads a moving original of sheet type, is
referred to as a first reading mechanism R1 and a reading
mechanism, that reads a stationary original with the moving members
65 and 66, is referred to as a second reading mechanism R2.
[0150] In FIG. 5, the first reading mechanism R1 is indicated as
representing the image sensor 78 of the automatic document feeder
or ADF 250 and the second reading mechanism R2 is indicated in the
middle of the scanner 200. The scanner 200 is regarded as the
second reading mechanism R2 when reading a stationary original
pressed by the pressure plate 70. However, the scanner 200 is
regarded as a part of the first reading mechanism R1 when an
original of sheet type is read, while it is transferred by the
automatic document feeder or ADF 250 with the moving members 65 and
66 stopped at the reading position under the contact glass 63. That
is, the first reading mechanism R1 includes a part centered with
the image sensor 78 of the automatic document feeder or ADF 250 and
a part which is the scanner 200 with the moving members 65 and 66
stopped at the reading position under the contact glass 63.
[0151] When an original to be read is a transparent sheet, a color
of the pressure plate may be read as a background. Therefore, the
pressure plate 70 has the white sheet 69 adhered on the surface
facing the original. Likewise, the transfer roller 77 and the sheet
pressure plate 79 are made so as to be white in color.
[0152] FIG. 7 is a cross-sectional view of the image sensor 78. As
shown in FIG. 7, the image sensor 78 includes a glass 83 facing an
original, a light source 84 (i.e., a light emitting diode or LED)
for lighting an image surface of an original, a lens array 85 for
making an image in focus, and an equal magnification lens 86. A
close-contact sensor, which requires no focusing lens, may be
substituted for the image sensor 78.
[0153] When an original of a relatively thick book is placed on the
second reading mechanism R2, the thick book is pressed by the
pressure plate 70 and accordingly, the first reading mechanism R1
is lifted up. This leads to a separation of the sheet pressure
plate 79 away from the contact glass 63. For this reason, the
automatic document feeder or ADF 250 is provided with a sensor (not
shown) for detecting when the sheet pressure plate 79 is moved away
from the contact glass 63. Based on this detection, a use of the
first reading mechanism R1 is inhibited.
[0154] When an emergency job, which includes both reading and image
forming, occurs during a reading process of a sheet original with
the first reading mechanism R1, the image forming apparatus of FIG.
5 allows an interruption due to such an emergency job even though
the sheet original is present on the sheet bed 71 or the ejection
tray 82. By the interruption, the second reading mechanism R2 is
allowed to perform the reading of an original placed on the contact
glass 62. The interruption is entered through the control panel 50
of FIG. 6.
[0155] FIG. 8 shows another image forming apparatus according to an
embodiment of the present invention. As shown in FIG. 8, the image
forming apparatus does not have the automatic document feeder or
ADF 250. In accordance with the removal of the automatic document
feeder or ADF 250, the pressure plate 70 is differently configured.
Therefore, other than the removal of the automatic document feeder
or ADF 250, the image forming apparatus of FIG. 8 is basically the
same as that of FIG. 5. In the image forming apparatus of FIG. 8,
the surface of the original facing the contact glass 62 is read by
the second reading mechanism R2 during one scanning process, while
both surfaces of the original can be read with the first and second
reading mechanisms R1 and R2 during one transfer process in the
image forming apparatus of FIG. 5. When an original is placed on
the contact glass 62 in the image forming apparatus of FIG. 5, the
surface of the original facing the contact glass 62 is read by the
second reading mechanism R2 during one scanning process.
[0156] In both image forming apparatuses of FIGS. 5 and 8, the page
orders of the recording sheets P stacked in the stacker 40 and the
recording sheets P stacked in the ejection tray 44 are different,
as described above. Accordingly, the image forming apparatuses of
FIGS. 5 and 8 are configured to control the page order of the
recording sheets P ejected either to the stacker 40 or the ejection
tray 44 in a manner as described above when originals are read with
either the first reading mechanism R1 or the second reading
mechanism R2.
[0157] FIG. 9 is a table summarizing a relationship between manners
of reading originals and manners of recording pages which are
achieved by the image forming apparatuses of FIGS. 5 and 8. In the
table of FIG. 9, an item I indicates which one of the first reading
mechanism R1 and the second reading mechanism R2 is used and an
item II indicates whether an original is single-sided, abbreviated
as S-S, or double-sided, abbreviated as D-S. Further, an item III
indicates an order of page reading, in which a page number, in
brackets, indicates a blank page. Further, an item IV indicates
which one of the stacker 40 and the ejection tray 44 is used and an
item V indicates which one of the single-sided recording operation,
abbreviated as S-S, and the double-sided recording operation,
abbreviated as D-S, is performed. Further, an item VI indicates an
order of page generation and an item VII indicates processes
performed. In item VII, a process 1 transfers an image from the
photoconductive drum 1 to the intermediate transfer belt 10, a
process 2 transfers an image from the photoconductive drum 1 to the
recording sheet P, and a process 3 transfers an image from the
intermediate transfer belt 10 to the recording sheet P.
[0158] In the image forming apparatus of FIG. 8, a sheet path for
ejecting the recording sheet P to the stacker 40 is configured to
turn the recording sheet P so that the recording sheet P is ejected
to the stacker 40 in a face down manner. This operation is referred
to as a reverse ejection. A sheet path for ejecting the recording
sheet P to the ejection tray 44 is configured to eject it in a
straight or forward manner so that the recording sheets P are
stacked in the ejection tray 44 in a face up manner. This operation
is referred to as a straight or forward ejection. Therefore, in
order to eject the recording sheets P in increasing order of page
numbers, an order of generating pages is different between the
cases of ejection to the stacker 40 and to the ejection tray
44.
[0159] The apparatus of FIG. 8 uses a method of double-sided
recording in which two pages of images for the first and second
surfaces are stored before starting the image forming process and
both of the photoconductive drum 1 and the intermediate transfer
belt 10 are effectively involved in the image forming process
without being stopped.
[0160] In the table of FIG. 9, the reading manner a and b represent
the sheet scanning mode of the image forming apparatus of FIG. 5
and the reading manner c and d represent the book scanning mode of
the image forming apparatuses of FIGS. 5 and 8. In the reading
manner b and d, the fourth page is a white page as so
indicated.
[0161] The recording manner A and B represent the cases where the
recording sheets P are ejected to the stacker 40 and the recording
manner C and D represent the cases where the recording sheets P are
ejected to the ejection tray 44.
[0162] In combining the above-described reading manners and
recording manners, one can come up with sixteen different image
reading and recording methods. Amongst the sixteen methods, when
single-sided originals are read with the automatic document feeder
or ADF 250 in the sheet scanning mode, the original is read by the
charge-coupled device or CCD 68 under the conditions that the
moving members 65 and 66 are stopped at the reading position under
the contact glass 63 since the first page of the originals faces up
in the sheet bed 71 of the automatic document feeder or ADF 250.
When double-sided originals are read with the automatic document
feeder or ADF 250 in the sheet scanning mode, the even-numbered
page is read by the image sensor 78 and the odd-numbered page is
read by the charge-coupled device or CCD 68 with the moving members
65 and 66 stopped at the reading position under the contact glass
63. When single-sided or double-sided originals are read
sheet-by-sheet in the book scanning mode, the original is read by
the charge-coupled device or CCD 68 moved with the moving members
65 and 66. In this case, the original placed on the contact glass
62 is manually turned.
[0163] Next, each of the sixteen methods is explained.
[0164] (1) In a method "Aa," single-sided originals are read with
the first reading mechanism R1, the read images are in turn
reproduced on the recording sheets P in the single-sided recording
mode, and the single-sided recording sheets P are in turn ejected
to the stacker 40. The originals are transferred by the automatic
document feeder or ADF 250 sheet-by-sheet and are read in order of
page numbers 1, 2, 3, 4, and so on. The images are formed on the
photoconductive drum 1 in order of page numbers 1, 2, 3, 4, and so
on. Each of the formed images is transferred from the
photoconductive drum 1 to the recording sheet P (i.e., the process
2) and is ejected to the stacker 40. Thereby, the single-sided
recording sheets P are stacked face down in the proper page number
order.
[0165] Thus, the single-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
single-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0166] In reading the single-sided originals in increasing order of
sheet numbers, the sheet that is first read is not called the first
sheet but the sheet that has the first page is called the first
sheet, as in the case of the recording process. Likewise, in
reading double-sided originals, the sheet that has the first and
second pages is called first sheet and the reading is performed in
increasing order of page numbers and sheet numbers.
[0167] Some reading apparatuses are configured to read originals
from the last sheet. Accordingly, the last page is first read and
the reading is performed in decreasing order of page numbers. In
these apparatuses, the sheet that is first read may be the first
sheet although it has the last page.
[0168] (2) In a method "Ab," double-sided originals are read with
the first reading mechanism R1, the read images are in turn
reproduced on the recording sheets P in the single-sided recording
mode, and the resultant single-sided recording sheets P are in turn
ejected to the stacker 40. The originals are transferred by the
automatic document feeder or ADF 250 sheet-by-sheet and are read in
order of even-numbered and odd-numbered pages, such as 2, 1, 4, 3,
and so on. This is because the image sensor 78, that reads
even-numbered pages, is located upstream and the contact glass 63,
that reads odd-numbered pages is located downstream. The images are
formed on the photoconductive drum 1 in order of page numbers 1, 2,
3, 4, and so on. However, the fourth page is detected as a white
page by the image sensor 78 and therefore, no image is formed for
the fourth page. Each of the formed images is transferred from the
photoconductive drum 1 to the recording sheet P (i.e., the process
2) and is ejected to the stacker 40. Thereby, the single-sided
recording sheets P are stacked face down in the proper page
order.
[0169] Thus, the double-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
single-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0170] (3) In a method "Ac," single-sided originals are read with
the second reading mechanism R2, the read images are in turn
reproduced on the recording sheets P in the single-sided recording
mode, and the resultant single-sided recording sheets P are in turn
ejected to the stacker 40. The single-sided originals are placed on
the contact glass 62 sheet-by-sheet in a desired order, or in an
increasing order of page numbers such as 1, 2, 3, 4, and so on, for
example, by the user. The originals are then read with the second
reading mechanism R2 in order of placements by the user, i.e., in
increasing order of page numbers such as 1, 2, 3, 4, and so on. The
images are formed on the photoconductive drum 1 in increasing order
of page numbers 1, 2, 3, 4, and so on. Each of the formed images is
transferred from the photoconductive drum 1 to the recording sheet
P (i.e., the process 2) and is ejected to the stacker 40. Thereby,
the single-sided recording sheets P are stacked face down in the
proper page order.
[0171] Thus, the single-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
single-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0172] (4) In a method "Ad," double-sided originals are read with
the second reading mechanism R2, the read images are in turn
reproduced on the recording sheets P in the single-sided recording
mode, and the resultant single-sided recording sheets P are in turn
ejected to the stacker 40. The double-sided originals are placed on
the contact glass 62 sheet-by-sheet in increasing order of page
numbers, such as 1, 2, 3, 4, and so on, for example, by the user.
The originals are then read with the second reading mechanism R2 in
order of placement by the user, i.e., in increasing order of page
numbers, such as 1, 2, 3, 4, and so on. The images are formed on
the photoconductive drum 1 in order of page numbers 1, 2, 3, 4, and
so on. However, since the fourth page is a white page, the user
does not let it be read and therefore, no image is formed for the
fourth page. Each of the formed images is transferred from the
photoconductive drum 1 to the recording sheet P (i.e., the process
2) and is ejected to the stacker 40. Thereby, the single-sided
recording sheets P are stacked face down in the proper page
order.
[0173] Thus, the double-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
single-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0174] (5) In a method "Ba," single-sided originals are read with
the first reading mechanism R1, the read images are in turn
reproduced on the recording sheets P in the double-sided recording
mode, and the double-sided recording sheets P are in turn ejected
to the stacker 40. The single-sided originals are transferred by
the automatic document feeder or ADF 250 sheet-by-sheet and are
read in order of page numbers 1, 2, 3, 4, and so on. The images are
formed on the photoconductive drum 1 in order of even-numbered and
odd-numbered pages, such as 2, 1, 4, 3, and so on. The double-sided
recording process is as follows. An image of the even-numbered page
is transferred from the photoconductive drum 1 to the intermediate
transfer belt 10 (i.e., the process 1). An image of the
odd-numbered page is transferred from the photoconductive drum 1 to
the second surface of the recording sheet P (i.e., the process 2).
The image of the even-numbered page is transferred from the
intermediate transfer belt 10 to the first surface of the recording
sheet P (i.e., the process 3). Then, the double-sided recording
sheet P is ejected to the stacker 40. The processes 1-3 are
repeated. Thereby, the double-sided recording sheets P are stacked
face down in the proper page order.
[0175] Thus, the single-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
double-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0176] (6) In a method "Bb," double-sided originals are read with
the first reading mechanism R1, the read images are in turn
reproduced on the recording sheets P in the double-sided recording
mode, and the double-sided recording sheets P are in turn ejected
to the stacker 40. The double-sided originals are transferred by
the automatic document feeder or ADF 250 sheet-by-sheet and are
read in order of even-numbered and odd-numbered pages, such as 2,
1, 4, 3, and so on. The images are formed on the photoconductive
drum 1 in a patterned order of page numbers being read, such as 2,
1, 4, 3, and so on, in the double-sided recording mode (i.e., the
processes 1-3). Then, the double-sided recording sheet P is ejected
to the stacker 40. In the above procedure, however, the fourth page
is a white page which is detected by the image sensor 78. In this
case, no image is formed the fourth page and the image of the third
page is generated through the process 2. Thereby, the double-sided
recording sheets P are stacked face down in the proper page
order.
[0177] Thus, the single-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
double-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0178] (7) In a method "Bc," single-sided originals are read with
the second reading mechanism R2, the read images are in turn
reproduced on the recording sheets P in the double-sided recording
mode, and the double-sided recording sheets P are in turn ejected
to the stacker 40. The single-sided originals are placed on the
contact glass 62 sheet-by-sheet in a desired order, or in an
increasing order of pages, by the user. The originals are then read
with the second reading mechanism R2 in order of placement by the
user, i.e., in increasing order of page numbers, such as 1, 2, 3,
4, and so on. The images are formed on the photoconductive drum 1
in a pattern of even-numbered and odd-numbered pages, such as 2, 1,
4, 3, and so on, in the double-sided recording mode (i.e., the
processes 1-3). Then, the double-sided recording sheet P is ejected
to the stacker 40. The processes 1-3 are repeated for each cycle of
the double-sided recording mode. Thereby, the double-sided
recording sheets P are stacked face down in the proper page
order.
[0179] Thus, the single-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
double-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0180] (8) In a method "Bd," double-sided originals are read with
the second reading mechanism R2, the read images are in turn
reproduced on the recording sheets P in the double-sided recording
mode, and the double-sided recording sheets P are in turn ejected
to the stacker 40. The double-sided originals are placed on the
contact glass 62 sheet-by-sheet in a desired order, or in an
increasing order of pages from the first page, for example, by the
user. The originals are then read with the second reading mechanism
R2 in order of placement by the user, i.e., in increasing order of
page numbers, such as 1, 2, 3, 4, and so on. The fourth page,
however, is a white page and the user would normally not let it be
read. Therefore, after the placement of the third page on the
contact glass 62, the user can instruct a start of the recording
via the control panel 50. The images are formed on the
photoconductive drum 1 in a pattern of even-numbered and
odd-numbered pages, such as 2 and 1 in the double-sided recording
mode via the processes 1-3 and the image of the third page is
generated via the process 2. Then, the double-sided recording
sheets P are in turn ejected to the stacker 40. Thereby, the
double-sided recording sheets P are stacked face down in the proper
page order. As described above, even when the last page is a white
page, the user can simply start the recording by, for example,
pressing a start button on the control panel 50 so as to obtain the
proper double-sided output including the last page.
[0181] Thus, the single-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
double-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0182] (9) In a method "Ca," single-sided originals are read with
the first reading mechanism R1, the read images are in turn
reproduced on the recording sheets P in the single-sided recording
mode, and the single-sided recording sheets P are in turn ejected
to the ejection tray 44. The single-sided originals are transferred
by the automatic document feeder or ADF 250 sheet-by-sheet and are
read in order of page numbers 1, 2, 3, 4, and so on. The images are
formed on the photoconductive drum 1 in order of page numbers being
read, such as 1, 2, 3, 4, and so on. Each formed image is recorded
on the first surface of the recording sheet P via the processes 1
and 3. More specifically, the image is transferred from the
photoconductive drum 1 to the intermediate transfer belt 10 (i.e.,
the process 1) and is further transferred from the intermediate
transfer belt 10 to the recording sheet P (i.e., the process 3).
Then, the double-sided recording sheet P is ejected straight to the
ejection tray 44. Thereby, the single-sided recording sheets P are
stacked face down in the proper page order.
[0183] Thus, the single-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
single-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0184] (10) In a method "Cb," double-sided originals are read with
the first reading mechanism R1, the read images are in turn
reproduced on the recording sheets P in the single-sided recording
mode, and the resultant single-sided recording sheets P are in turn
ejected to the ejection tray 44. The originals are transferred by
the automatic document feeder or ADF 250 sheet-by-sheet and are
read in a pattern of even-numbered and odd-numbered pages, such as
2, 1, 4, 3, and so on. The images are formed on the photoconductive
drum 1 in order of page numbers 1, 2, 3, 4, and so on. However, the
fourth page is detected as a white page by the image sensor 78 and
therefore, no image is formed for the fourth page. Each of the
formed images is transferred from the photoconductive drum 1 to the
intermediate transfer belt 10 (i.e., the process 1) and then from
the intermediate transfer belt 10 to the first surface of the
recording sheet P (i.e., the process 3). The recording sheet P
having the image on the lower surface thereof is ejected to the
ejection tray 44. Thereby, the single-sided recording sheets P are
stacked face down in the proper page order.
[0185] Thus, the double-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
single-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0186] (11) In a method "Cc," single-sided originals are read with
the second reading mechanism R2, the read images are in turn
reproduced on the recording sheets P in the single-sided recording
mode, and the resultant single-sided recording sheets P are in turn
ejected to the ejection tray 44. The single-sided originals are
placed by the user on the contact glass 62 sheet-by-sheet in a
desired order, or in an increasing order of page numbers, such as
1, 2, 3, 4, and so on, for example. The originals are then read
with the second reading mechanism R2 in order of placement by the
user, i.e., in increasing order of page numbers, such as 1, 2, 3,
4, and so on. The images are formed on the photoconductive drum 1
in increasing order of page numbers 1, 2, 3, 4, and so on. Each of
the formed images is transferred eventually to the lower surface of
the recording sheet P via the processes 1 and 3, and is ejected to
the ejection tray 44. Thereby, the single-sided recording sheets P
are stacked face down in the proper page order.
[0187] Thus, the single-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
single-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0188] (12) In a method "Cd," double-sided originals are read with
the second reading mechanism R2, the read images are in turn
reproduced on the recording sheets P in the single-sided recording
mode, and the resultant single-sided recording sheets P are in turn
ejected to the ejection tray 44. The double-sided originals are
placed by the user on the contact glass 62 sheet-by-sheet in
increasing order of page numbers, such as 1, 2, 3, 4, and so on,
for example. The originals are then read with the second reading
mechanism R2 in order of placement by the user, i.e., in increasing
order of page numbers, such as 1, 2, 3, 4, and so on. The images
are formed on the photoconductive drum 1 in increasing order of
page numbers 1, 2, 3, 4, and so on. However, since the fourth page
is a white page, the user does not let it be read and therefore, no
image is formed for the fourth page. Each of the formed images is
transferred from the photoconductive drum 1 eventually to the lower
surface of the recording sheet P via the processes 1 and 3, and is
ejected to the ejection tray 44. Thereby, the single-sided
recording sheets P are stacked face down in the proper page
order.
[0189] Thus, the double-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
single-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0190] (13) In a method "Da," single-sided originals are read with
the first reading mechanism R1, the read images are in turn
reproduced on the recording sheets P in the double-sided recording
mode, and the double-sided recording sheets P are in turn ejected
to the ejection tray 44. The single-sided originals are transferred
by the automatic document feeder or ADF 250 sheet-by-sheet and are
read in increasing order of page numbers 1, 2, 3, 4, and so on. The
images are formed on the photoconductive drum 1 in increasing order
of page numbers being read, such as 1, 2, 3, 4, and so on. In this
case, the single-sided recording operation performs the processes
1-3 so that an image of the odd-numbered page is transferred to
from the photoconductive drum 1 via the intermediate transfer belt
10 to the lower surface of the recording sheet P (i.e., the process
1 and 2) and an image of the even-numbered page is transferred from
the photoconductive drum 1 to the upper surface of the recording
sheet P (i.e., the process 3). Then, the double-sided recording
sheet P is ejected to the ejection tray 44. The processes 1-3 are
repeated. Thereby, the double-sided recording sheets P are stacked
face down in the proper page order.
[0191] Thus, the single-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
double-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0192] (14) In a method "Db," double-sided originals are read with
the first reading mechanism R1, the read images are in turn
reproduced on the recording sheets P in the double-sided recording
mode, and the double-sided recording sheets P are in turn ejected
to the ejection tray 44. The double-sided originals are transferred
by the automatic document feeder or ADF 250 sheet-by-sheet and are
read in a pattern of even-numbered and odd-numbered pages, such as
2, 1, 4, 3, and so on. The images are formed on the photoconductive
drum 1 in increasing order of page numbers, such as 1, 2, 3, 4, and
so on, in the double-sided recording mode (i.e., the processes
1-3). Then, the double-sided recording sheet P is ejected to the
ejection tray 44. In the above procedure, however, the fourth page
is a white page which is detected by the image sensor 78. In this
case, no image is formed the fourth page and the image of the third
page is generated on the lower surface of the recording sheet P via
the processes 1 and 3. Thereby, the double-sided recording sheets P
are stacked face down in the proper page order.
[0193] Thus, the single-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
double-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0194] (15) In a method "Dc," single-sided originals are read with
the second reading mechanism R2, the read images are in turn
reproduced on the recording sheets P in the double-sided recording
mode, and the double-sided recording sheets P are in turn ejected
to the ejection tray 44. The single-sided originals are placed on
the contact glass 62 sheet-by-sheet in a desired order, or in an
increasing order of page numbers, by the user. The originals are
then read with the second reading mechanism R2 in order of
placement by the user, i.e., in increasing order of page numbers,
such as 1, 2, 3, 4, and so on. The images are formed on the
photoconductive drum 1 in increasing order of page numbers being
read, such as 1, 2, 3, 4, and so on, in the double-sided recording
mode (i.e., the processes 1-3). Then, the double-sided recording
sheet P is ejected to the ejection tray 44. The processes 1-3 are
repeated for each cycle of the double-sided recording mode.
Thereby, the double-sided recording sheets P are stacked face down
in the proper page order.
[0195] Thus, the single-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
double-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0196] (16) In a method "Dd," double-sided originals are read with
the second reading mechanism R2, the read images are in turn
reproduced on the recording sheets P in the double-sided recording
mode, and the double-sided recording sheets P are in turn ejected
to the ejection tray 44. The double-sided originals are placed on
the contact glass 62 sheet-by-sheet in a desired order, or in an
increasing order of page numbers from the first page, for example,
by the user. The originals are then read with the second reading
mechanism R2 in order of placement by the user, i.e., in increasing
order of page numbers, such as 1, 2, 3, 4, and so on. The fourth
page, however, is a white page and the user would normally not let
it be read. Therefore, after the placement of the third page on the
contact glass 62, the user can instruct a start of the recording
via the control panel 50. The images are formed on the
photoconductive drum 1 in increasing order of page numbers 1 and 2
in the double-sided recording mode (i.e., the processes 1-3) and
the image of the third page is generated through in the
single-sided recording mode (i.e., the processes 1 and 3). Then,
the double-sided recording sheets P are in turn ejected to the
ejection tray 44. Thereby, the double-sided recording sheets P are
stacked face down in the proper page order. As described above,
even when the last page is a white page, the user can simply start
the recording by, for example, pressing the start button on the
control panel 50 so as to obtain the proper double-sided output
including the last page.
[0197] Thus, the double-sided originals are read in increasing
order of sheet numbers 1, 2, 3, and so on, and the resultant
double-sided recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0198] In the above description, the operation for handling four
pages of originals is exemplified. However, it is noted that the
image forming apparatus of FIG. 5 can handle any number of pages of
originals in accordance with the table of FIG. 9 so as to output
the recorded sheets in the proper page order.
[0199] As described above, in any one of the sixteen cases, the
originals are read in increasing order of sheet numbers 1, 2, 3,
and so on, and the resultant recording sheets P are output in
increasing order of sheet numbers 1, 2, 3, and so on.
[0200] Therefore, in both double-sided and single-sided recording
modes, the user can easily check the contents of the recorded
images. In addition, the user can easily restart the reproduction
operation when a disturbance is caused due to a paper jam.
[0201] Further, since the image forming apparatus of FIG. 5 reads
the originals from the first sheet and outputs from the first
sheet, it can perform the image forming operation in an amount of
time faster than the apparatus that reads the originals from the
last sheet and outputs from the first sheet.
[0202] Further, since the image forming apparatus of FIG. 5 reads
the originals from the first sheet and outputs from the first
sheet, two pages of images need to be stored. This is far smaller
than in comparison to the case where an apparatus reads the
originals from the last sheet and outputs from the first sheet.
[0203] In the image forming apparatus of FIG. 5, temperature of the
fixing rollers 18 and 19 can be controlled. This feature may be
applied also to other embodiments of the present invention. By
controlling the temperature of the fixing rollers 18 and 19, the
fixing process can be performed in an optimal condition in
accordance with whatever mode of image forming is chosen, i.e.,
single-sided recording mode or double-sided recording mode, and
whatever the type of recording sheet used, i.e., thick recording
sheet or thin recording sheet. For example, the double-sided
recording mode requires an amount of fixing energy greater than the
single-sided recording mode. Therefore, input voltages to the
fixing rollers 18 and 19 may be increased or may be applied in a
more frequent manner. In addition, in the single-sided recording
mode, the temperature of the fixing roller, at a side of the
recording sheet having no image, may be controlled to be reduced or
the input voltage to it may be turned off.
[0204] In the image forming apparatus of FIG. 5, the toner image
transferred onto the intermediate transfer belt 10 needs to be
prevented from melting due to the high temperature of the fixing
rollers. To achieve this, an application of heat to the fixing
rollers 18 and 19 is stopped or controlled during the process while
the toner images are transferred from the photoconductive drum 1 to
the intermediate transfer belt 10. As a result, the toner image on
the intermediate transfer belt 10 is prevented from melting due to
the high temperature of the fixing rollers.
[0205] In the image forming apparatus of FIG. 5, the intermediate
transfer belt 10 is closely contacted by the fixing rollers 18 and
19, which may adversely affect the toner image on the intermediate
transfer belt 10. To avoid this from happening, the cooling rollers
16 are arranged to cool down the intermediate transfer belt 10.
[0206] FIG. 10 shows an image forming system which includes the
image forming apparatus of FIG. 5 and additional apparatuses. As
shown in FIG. 10, the image forming system includes sheet banks PT1
and PT2 and additional ejection apparatuses EXT1 and EXT2. The
sheet banks PT1 and PT2 are arranged under the sheet cassette 26.
The ejection apparatus EXT1 is arranged at a side of the automatic
document feeder or ADF 250 and over the manual sheet inlet 35 and
the ejection apparatus EXT2 is arranged at another side of the
automatic document feeder or ADF 250 and over the ejection tray 44.
Each of the ejection apparatuses EXT1 and EXT2 includes a plurality
of bins which each receive the ejected recording sheets P. Each of
the ejection apparatuses EXT1 and EXT2 may be a sorter for grouping
recording sheets by sorting the recording sheets in increasing page
number order or a collator for grouping recording sheets by
collating the recording sheets with the same page number. It is
also possible to install a stapling machine for stapling each stack
of sheets sorted by the sorter or collated by the collator.
[0207] An additional sheet path Q1 is provided in the sheet
ejection space above the stacker 40 to guide the recording sheet P
sent from the ejection rollers 34 to the ejection apparatus EXT1. A
switching pawl 41 is provided on an edge portion of the sheet path
Q1 close to the ejection rollers 34 to switch paths for guiding the
recording sheet P to either the stacker 40 or to the ejection
apparatus EXT1. The sheet path Q1 is arranged at the uppermost
position of the ejection space over the stacker 40 such that the
stacker 40 can be used without being disturbed by the sheet path
Q1.
[0208] An additional sheet path Q2 is arranged to guide the
recording sheet P, ejected from the ejection rollers 32, to the
ejection apparatus EXT2. A switching pawl is provided at an edge
portion of the sheet path Q2 close to the ejection rollers 32 so as
to switch paths for guiding the recording sheet P to either the
ejection tray 44 or to the ejection apparatus EXT2.
[0209] When the recording sheet P is ejected to the ejection
apparatus EXT1, it is reversed and is ejected in the same
orientation as in the case of the ejection to the stacker 40.
Therefore, the rules of the sheet handling, shown in the table of
FIG. 9, can be applied to the case of handling the recording sheet
P using the ejection apparatus EXT1.
[0210] When the recording sheet P is ejected to the ejection
apparatus EXT2, it is not reversed and is ejected in the same
orientation as in the case of the ejection to the ejection tray 44.
Therefore, the rules of the sheet handling, shown in the table of
FIG. 9, can be applied to the case of handling the recording sheet
P using the ejection apparatus EXT1.
[0211] Alternatively, it is possible to configure a system having
the printer 100, of FIG. 2, with the addition of the ejection
apparatuses EXT1 and EXT2, although the printer 100 has no scanning
machine.
[0212] Next, another image forming apparatus, according to an
embodiment of the present invention, is explained with reference to
FIG. 1. The image forming apparatus, of FIG. 11, includes a printer
100C, a scanner 200B, and an automatic document feeder or ADF 250B.
The printer 100C is similar to the printer 100 of FIG. 2, except
for having a fixing unit 30B, which is arranged outside of the
intermediate transfer belt 10. The scanner 200B is similar to the
scanner 200 of FIG. 5, except for a contact glass 62b which is
substituted for the contact glasses 62 and 63. The automatic
document feeder or ADF 250B is configured to circulate
originals.
[0213] In the image forming apparatus of FIG. 11, the recording
sheet P, having the transferred toner image thereon, is transferred
to the fixing unit 30B and is subjected to the fixing process,
after being separated from the intermediate transfer belt 10. Since
the fixing unit 30B is not arranged inside of, but rather outside
of the intermediate transfer belt 10, it is necessary that the
fixing unit 30B be close to the intermediate transfer belt 10 so as
to prevent the recording sheet P from becoming bent so that the
unfixed toner image is not disturbed. This is possible since the
intermediate transfer belt 10 has a property of heat resistance.
This arrangement eliminates necessity of a conveyor having
star-like wheels between the intermediate transfer belt 10 and the
fixing unit 30B.
[0214] In addition, the cleaning unit 25 of the printer 100C is
configured to clean the intermediate transfer belt 10 directly with
the cleaning blade 25b.
[0215] The automatic document feeder or ADF 250B is provided with
the sheet bed 71, the moving plate 72, and the sheet transfer
mechanism 73, which includes all of the transfer roller 74, the
separation rollers 75, and transfer rollers 76, as in the case of
the automatic document feeder or ADF 250 of FIG. 5.
[0216] The automatic document feeder or ADF 250B includes a
transfer belt 90, a driving roller 91, a following roller 92, and a
plurality of pressing rollers 93. The transfer belt 90 is arranged
at a lower part of the automatic document feeder or ADF 250B and
extends, under pressure, between the driving roller 91 and the
following roller 92 so as to be rotated therebetween. The positions
of the driving roller 91 and the following roller 92 can be
exchanged with each other. The pressing rollers 93 are arranged
inside the transfer belt 90 such that the transfer belt 90 applies
a slight pressure to the contact glass 62b, when the automatic
document feeder or ADF 250B is in a closed state, to read
originals.
[0217] The A\automatic document feeder or ADF 250B further includes
a turn roller 94, a following roller 95, a switching pawl 96, a
supporting shaft 97, a guide member 98, an ejection tray 99, a pair
of ejection rollers 101, a guide member 102, and a cover 103. The
turn roller 94 is arranged to the right side of the transfer belt
90 and in contact with the following roller 95 under pressure. The
switching pawl 96 is arranged between the turn roller 94 and the
ejection rollers 101 and is pivoted about the supporting shaft 97
by an actuator (not shown), such as a solenoid, for example. The
guide member 98 is arranged between the turn roller 94 and the
transfer belt 90.
[0218] In the automatic document feeder or ADF 250B having the
above-described structure, an original is transferred to the
contact glass 62b and is stopped thereon. Then, the original is
read by the scanner 200B in a manner similar to the scanner 200 as
described earlier with reference to FIG. 5. When the original is
double-sided, the original is turned after one side is read so that
the other side can be read.
[0219] An original can be placed on the contact glass 62c manually
by the user by opening the automatic document feeder or ADF
250B.
[0220] A stack of the sheet-formed originals S are placed on the
moving plate 72 with the first page positioned uppermost and the
leading edge thereof pressed against the transfer roller 74 with a
pressure member (not shown). The transfer roller 74 is rotated
clockwise, as shown in FIG. 11, and consequently, the first sheet
on the top of the stack is fed to a nip portion of the separation
rollers 75. Thereby, the stack of the sheet-formed originals S are
transferred sheet-by-sheet. The sheet-formed original S is further
transferred to a nip portion between the transfer belt 90 and the
contact glass 62b via the transfer rollers 76. A cover of the sheet
transfer mechanism 73 is configured to open so that the user is
allowed to access an inside sheet path to remove a paper jam.
[0221] The transfer belt 90 can be movable in directions indicated
by arrows C1 and C2. When the transfer belt 90 is moved in the
direction C1, the sheet-formed original S is transferred in the
forward direction. The transfer belt 90 is stopped in a
predetermined time so as to locate the sheet-formed original S at a
predetermined reading position on the contact glass 62b. Then, the
first page of the sheet-formed original S is scanned with the light
source 64 (as discussed above with respect to FIG. 5) and the
moving members 65 and 66 (as discussed above with respect to FIG.
5). After that, the transfer belt 90 is moved in the direction C2
to further transfer the sheet-formed original S to the turn roller
94.
[0222] The sheet-formed original S is transferred into the nip
between the turn roller 94 and the following roller 95 and is
turned along the guide member 102 and the switching pawl 96, which
was switched to an upper position indicated by the
upwardly-directed arrow of the double-sided pivot arrow associated
with switching pawl 96 as shown in FIG. 11. Then, the sheet-formed
original S is guided under the transfer belt 90 by the guide member
98. At this time, the transfer belt 90 is moved in the direction C2
for a predetermined time period so as to transfer the sheet-formed
original S to the predetermined reading position. Then, the second
page of the sheet-formed original S is read in the same manner as
the first page is read. After a completion of reading the second
page, the transfer belt 90 is moved in the direction C1 to transfer
the original in the forward direction. The switching pawl 96 is
switched to a lower position, indicated by the downwardly-directed
arrow of the double-sided pivot arrow associated with switching
pawl 96 as shown in FIG. 11, so that the sheet-formed original S is
guided in the direction of arrow B to ejection rollers 101.
Thereby, the sheet-formed original S is ejected to an ejection tray
99 and is stacked face down in the ejection tray 99. That is, the
first page faces down and the stack of the sheet-formed originals S
are held in increasing order of page numbers in the ejection tray
99.
[0223] The guide member 102 is formed to have a plurality of ribs
such that the sheet-formed original S is transferred with a
relatively small area contacting the guide member 102. The guide
member 102 is a part of the cover and is configured to be opened so
that the user can easily access an internal sheet path to remove
paper jam.
[0224] It is preferable that the user accesses the image forming
apparatus of FIG. 11 at a position in front of it and in a
direction perpendicular to FIG. 11 by placing a stack of
sheet-formed originals S on the sheet bed 71, removing a stack of
read sheet-formed originals S from the ejection tray 99, removing
the recorded sheets P from the stacker 40, etc.
[0225] The image forming apparatus of FIG. 11, having the
above-described structure, works according to the rules of sheet
handling shown in the table of FIG. 9. That is, the sheet-formed
originals S are read in increasing order of sheet numbers 1, 2, 3,
and so on, and the resultant recording sheets P are output in
increasing order of sheet numbers 1, 2, 3, and so on.
[0226] Therefore, in both double-sided and single-sided recording
modes, the user can easily check the contents of the recorded
images. In addition, the user can easily restart the reproduction
operation when a disturbance is caused due to a paper jam.
[0227] Further, since the image forming apparatus of FIG. 11 reads
the originals from the first sheet and outputs from the first
sheet, it can perform the image forming operation in a time faster
than the apparatus that reads the originals from the last sheet and
outputs from the first sheet.
[0228] Further, since the image forming apparatus of FIG. 11 reads
the originals from the first sheet and outputs from the first
sheet, two pages of images must be stored. This is a far smaller
amount that needs to be stored in comparison to the case of an
apparatus that reads the originals from the last sheet and outputs
from the first sheet.
[0229] Next, a color image forming apparatus, according to an
embodiment of the present invention, is explained with reference to
FIG. 12. The image forming apparatus, of FIG. 12, includes the
color printer 10B, of FIG. 4, and both the scanner 200 and the
automatic document feeder or ADF 250, of FIG. 5. The color image
forming apparatus, of FIG. 12, is provided with a multi-function
controller (not shown) for performing multi-functions as a copying
machine, a facsimile machine, and a printer.
[0230] The color image forming apparatus, of FIG. 12, basically
performs the operations in the same manner as the image forming
apparatus of FIG. 5 does, except for the following. That is, in the
color image forming apparatus of FIG. 12, the intermediate transfer
belt 10 is separated away from the photoconductive drum 1 and is
stopped on standby after the toner image for the first page is
transferred to the intermediate transfer belt 10 when a
double-sided original is read. During standby, the toner image for
the second page is formed on the photoconductive drum 1. On the
other hand, in the image forming apparatus of FIG. 5, neither the
photoconductive drum 1 nor the intermediate transfer belt 10 is
stopped during the image forming process. This is the difference
between the color image forming apparatus of FIG. 12 and the image
forming apparatus of FIG. 5.
[0231] The first and second reading mechanisms R1 and R2 is
configured as color scanners for reading color image information of
an original in each separate color of red (R), green (G), and blue
(B) and converting the read information into electrical signals. A
color image sensor of each reading mechanism R1 and R2 includes R,
G, and B separators and photoelectric devices to simultaneously
read three color images separated in R, G, and B and to generate R,
G, and B image signals in parallel. Then, an image processing unit
(not shown) performs a color conversion to generate color image
data of black (Bk), cyan (C), magenta (M), and yellow (Y) colors in
accordance with intensity of the R, G, and B image signals.
[0232] The first and second reading mechanisms R1 and R2 perform
color scanning operations in the following manner. The first and
second reading mechanisms R1 and R2 start scanning on the original
upon receiving a scan start signal sent in synchronism with the
operations of the color printer 100B, and then output image data in
each of the four colors black (Bk), cyan (C), magenta (M), and
yellow (Y). The color printer 100B in turn performs the image
forming processes for the four color toner images and overlays them
on top of each other so as to generate a full color toner image.
The color image forming apparatus of FIG. 12 is configured to read
the image data in each of the four colors during one scanning
process so as to be able to capture color image data from the first
and second surfaces of a double-sided original during a time of
transferring that original.
[0233] The color image forming apparatus of FIG. 12, structured as
described above, works according to the rules of sheet handling
shown in the table of FIG. 9. That is, the originals are read in
increasing order of sheet numbers 1, 2, 3, and so on, and the
resultant recording sheets P are output in increasing order of
sheet numbers 1, 2, 3, and so on.
[0234] Therefore, in both double-sided and single-sided recording
modes, the user can easily check the contents of the recorded
images. In addition, the user can easily restart the reproduction
operation when a disturbance is caused due to a paper jam.
[0235] Further, since the color image forming apparatus of FIG. 12
reads the originals from the first sheet and outputs from the first
sheet, it can perform the image forming operation in a time faster
than the apparatus that reads the originals from the last sheet and
outputs from the first sheet.
[0236] Further, since the color image forming apparatus of FIG. 12
reads the originals from the first sheet and outputs from the first
sheet, two pages of images need to be stored. This is a far smaller
amount that needs to be stored than in comparison to the case of an
apparatus that reads the originals from the last sheet and outputs
from the first sheet.
[0237] In the above-described printer 100 of FIG. 2 and the color
printer 100B of FIG. 5, the intermediate transfer belt 10 may be
reversely-turned to a predetermined position after the first toner
image is transferred onto the intermediate transfer belt 10,
instead of being moved for one turn in the forward direction. In
this case, the photoconductive drum 1 and the intermediate transfer
belt 10 are configured to be able to contact each other and
separate from each other.
[0238] In addition, the printer 100 and the color printer 100B may
employ a belt-shaped photoconductive member in place of the
photoconductive drum 1.
[0239] Numerous additional modifications and variations of the
present invention are possible in light of the above teachings. It
is therefore to be understood that within the scope of the appended
claims, the present application may be practiced otherwise than as
specifically described herein.
* * * * *