U.S. patent application number 09/031770 was filed with the patent office on 2002-03-07 for image forming apparatus for forming image on free-size sheet having arbitrary size.
Invention is credited to CHIHARA, HIROSHI, ENDO, SOYA, KIMIZUKA, JUNICHI, NAKAMORI, TOMOHIRO, TAKAMI, HIROSHI.
Application Number | 20020027667 09/031770 |
Document ID | / |
Family ID | 13135696 |
Filed Date | 2002-03-07 |
United States Patent
Application |
20020027667 |
Kind Code |
A1 |
TAKAMI, HIROSHI ; et
al. |
March 7, 2002 |
IMAGE FORMING APPARATUS FOR FORMING IMAGE ON FREE-SIZE SHEET HAVING
ARBITRARY SIZE
Abstract
There is provided an image forming apparatus including an image
forming unit for forming an image on either a free-size sheet of an
arbitrary size other than a regular size or a regular-size sheet, a
controlling unit for controlling, when the image forming unit forms
the image on the regular-size sheet, a controlling target unit
according to a size of the regular-size sheet, an inputting unit
for inputting a size of the free-size sheet, and a converting unit
for converting the size inputted by the inputting unit, to suit the
converted size to the controlling performed by the controlling unit
to the regular-size sheet, wherein the controlling unit performs
the different controlling for each group of the sheet sizes, and
the converting unit performs the converting to suit the size of the
free-size sheet to the group.
Inventors: |
TAKAMI, HIROSHI;
(NUMAZU-SHI, JP) ; KIMIZUKA, JUNICHI;
(YOKOHAMA-SHI, JP) ; ENDO, SOYA; (NUMAZU-SHI,
JP) ; NAKAMORI, TOMOHIRO; (SUNTO-GUN, JP) ;
CHIHARA, HIROSHI; (MISHIMA-SHI, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Family ID: |
13135696 |
Appl. No.: |
09/031770 |
Filed: |
February 27, 1998 |
Current U.S.
Class: |
358/1.2 |
Current CPC
Class: |
H04N 1/2323 20130101;
G03G 15/2042 20130101; H04N 1/2338 20130101; H04N 1/0443 20130101;
H04N 1/0402 20130101; B41J 13/0054 20130101; H04N 1/1135 20130101;
H04N 1/0455 20130101; H04N 1/0405 20130101; H04N 1/12 20130101;
G06K 15/021 20130101; G03G 2215/00734 20130101; B41J 11/0025
20130101 |
Class at
Publication: |
358/1.2 |
International
Class: |
B41B 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 28, 1997 |
JP |
09-060214 |
Claims
What is claimed is:
1. An image forming apparatus comprising: image forming means for
forming an image on either a free-size sheet of an arbitrary size
other than a regular size or a regular-size sheet; controlling
means for controlling, when said image forming means forms the
image on the regular-size sheet, a controlling target unit
according to a size of the regular-size sheet; inputting means for
inputting a size of the free-size sheet; and converting means for
converting the size inputted by said inputting means, to suit the
converted size to the controlling performed by said controlling
means to the regular-size sheet.
2. An apparatus according to claim 1, wherein said controlling
means performs the different controlling for each group of the
sheet sizes, and said converting means performs the converting to
suit the size of the free-size sheet to the group.
3. An apparatus according to claim 1, wherein said controlling
means controls a heater of a fixing device contained in said image
forming means.
4. An apparatus according to claim 3, wherein said fixing device
has the plural heaters, and said controlling means controls power
conducting ratio to the plural heaters.
5. An apparatus according to claim 1, wherein said image forming
apparatus is a laser beam printer.
6. An apparatus according to claim 1, wherein said inputting means
inputs a width and a length of the free-size sheet on which the
image is to be formed.
7. An apparatus according to claim 1, wherein said inputting means
is provided on an operation panel.
8. An apparatus according to claim 1, wherein said inputting means
inputs the size from a sensor which senses the sheet size.
9. An image forming apparatus comprising: image forming means for
forming an image on a free-size sheet of an arbitrary size other
than a regular size; inputting means for inputting a size of the
free-size sheet; sampling means for performing different sampling
for each controlling target unit, on the size inputted by said
inputting means; and controlling means for controlling each
controlling target unit according to a sampling result of said
sampling means.
10. An apparatus according to claim 9, wherein said sampling means
performs fine sampling in correspondence with controlling to sheet
conveying.
11. An apparatus according to claim 9, wherein said sampling means
performs coarse sampling in correspondence with controlling to a
heater of a fixing device.
12. An apparatus according to claim 9, wherein, in case of
performing area controlling to the image formed on the sheet, said
controlling means does not use the sampling result of said sampling
means but uses the size inputted by said inputting means.
13. An apparatus according to claim 9, wherein said inputting means
inputs a width and a length of the free-size sheet on which the
image is to be formed.
14. An apparatus according to claim 9, wherein said inputting means
is provided on an operational panel.
15. An apparatus according to claim 9, wherein said inputting means
inputs the size from a sensor which senses the sheet size.
16. An image forming method comprising: an image forming step of
forming an image on either a free-size sheet of an arbitrary size
other than a regular size or a regular-size sheet; a controlling
step of controlling, when said image forming step forms the image
on the regular-size sheet, a controlling target unit according to a
size of the regular-size sheet; an inputting step of inputting a
size of the free-size sheet; and a converting step of converting
the size inputted in said inputting step, to suit the converted
size to the controlling performed in said controlling step to the
regular-size sheet.
17. A method according to claim 16, wherein said controlling step
performs the different controlling for each group of the sheet
sizes, and said converting step performs the converting to suit the
size of the free-size sheet to the group.
18. A method according to claim 16, wherein said controlling step
controls a heater of a fixing device used in said image forming
step.
19. A method according to claim 18, wherein the fixing device has
the plural heaters, and said controlling step controls power
conducting ratio to the plural heaters.
20. A method according to claim 16, wherein said image forming
method is performed by a laser beam printer.
21. A method according to claim 16, wherein said inputting step
inputs a width and a length of the free-size sheet on which the
image is to be formed.
22. A method according to claim 16, wherein said inputting step is
executed on an operation panel.
23. A method according to claim 16, wherein said inputting step
inputs the size from a sensor which senses the sheet size.
24. An image forming method comprising: an image forming step of
forming an image on a free-size sheet of an arbitrary size other
than a regular size; an inputting step of inputting a size of the
free-size sheet; a sampling step of performing different sampling
for each controlling target unit, on the size inputted in said
inputting step; and a controlling step of controlling each
controlling target unit according to a sampling result of said
sampling step.
25. A method according to claim 24, wherein said sampling step
performs fine sampling in correspondence with controlling to sheet
conveying.
26. A method according to claim 24, wherein said sampling step
performs coarse sampling in correspondence with controlling to a
heater of a fixing device.
27. A method according to claim 24, wherein, in case of performing
area controlling to the image formed on the sheet, said controlling
step does not use the sampling result of said sampling step but
uses the size inputted in said inputting step.
28. A method according to claim 24, wherein said inputting step
inputs a width and a length of the freesize sheet on which the
image is to be formed.
29. A method according to claim 24, wherein said inputting step is
executed on an operational panel.
30. A method according to claim 24, wherein said putting step
inputs the size from a sensor which senses the sheet size.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an image forming apparatus
which forms an image on a free-size sheet having an arbitrary size
other than regular sizes.
[0003] 2. Related Background Art
[0004] Generally, in an image forming apparatus such as a copy
machine, a printer or the like, a paper feeding device which has a
recording paper cassette putting (or loading) recording paper has
been widely used. In the recording paper cassette, there are a
recording paper cassette putting the recording paper of a regular
size such as an A4 size, an A3 size or the like and a free-size
cassette capable of putting the recording paper of an arbitrary
size.
[0005] In the image forming apparatus capable of having such the
free-size cassette, a size (longitudinal and lateral dimensions) of
the recording paper put in this free-size cassette is designated by
a user through a key operation, and controlling of image forming on
the recording paper is adaptively performed according to such the
designated recording-paper size. Concretely, the recording-paper
size is designated at accuracy in the unit of millimeter or less,
an operation condition about the image forming on the recording
paper is set based on the designated recording-paper size, and the
controlling is performed according to the set operation condition.
By setting the operation condition about the image forming on the
recording paper based on the designated recording-paper size and
performing the control according to the set operation condition in
this way, it is realized that the optimum image is formed on the
recording paper the size of which was designated.
[0006] However, in such a method as the operation condition about
the image forming on the recording paper is set based on the
designated recording-paper size and the image forming is controlled
based on the set condition, even if the operation condition may be
set as the condition which is not influenced by a slight difference
of the recording-paper size, it is possible that the operation
condition is set as a more strict condition than is necessary.
Therefore, there is some fear that the controlling becomes
complicated.
[0007] On the other hand, if the designated recording-paper size is
equal to or less than a predetermined size, there can be supposed a
method that the designated recording-paper size is considered as a
maximum size within a range capable of being handled and the
operation condition is set based on this maximum size, and in this
method the controlling does not become complicated. However, an
optimal throughput according to each recording-paper size can not
be obtained.
SUMMARY OF THE INVENTION
[0008] An object of the present invention is to provide an image
forming apparatus which solved such problems as described
above.
[0009] Another object of the present invention to provide an image
forming apparatus which can, in a case where image forming is
performed on a free-size sheet (or paper) having an arbitrary size
other than regular sizes, perform controlling suitable for such the
sheet size without lowering a throughput and making the controlling
complicated.
[0010] The above and other objects, features, and advantages of the
present invention will be apparent from the following detailed
description and the appended claims in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a structural view showing a first embodiment of an
image forming apparatus according to the present invention;
[0012] FIG. 2 is a block diagram showing a main portion of a
controlling system in a laser beam printer of FIG. 1;
[0013] FIG. 3 is a view showing an image area on a recording paper
(or sheet);
[0014] FIG. 4 is a view showing sampled data of a recording-paper
size in the laser beam printer of FIG. 1;
[0015] FIG. 5 is a flow chart showing image formation processing in
the laser beam printer of FIG. 1;
[0016] FIG. 6 is a flow chart showing sampling process procedure in
a step S103 of FIG. 5;
[0017] FIG. 7 is a block diagram showing the structure of an image
area controlling circuit provided within a printer controller of
the laser beam printer of FIG. 1;
[0018] FIG. 8 is a timing chart showing operation timing in the
image area controlling circuit of FIG. 7;
[0019] FIG. 9 is a timing chart showing operation timing of
recording-paper conveyance controlling at the time of printing by
the laser beam printer of FIG. 1;
[0020] FIG. 10 is a block diagram showing a main portion of a
controlling system in a second embodiment of the image forming
apparatus according to the present invention;
[0021] FIG. 11 is a flow chart showing a data writing task to an
NVRAM (Non-Volatile Random Access Memory) in a laser beam printer
of FIG. 10;
[0022] FIG. 12 is a flow chart showing a data reading task from the
NVRAM in the laser beam printer of FIG. 10;
[0023] FIG. 13 is a flow chart showing the data reading task from
the NVRAM in a case where plural kinds of free-size cassettes are
mounted to the laser beam printer of FIG. 10;
[0024] FIG. 14 is a structural view showing a third embodiment of
the image forming apparatus according to the present invention;
[0025] FIG. 15 is a block diagram showing a main portion of a
controlling system in a laser beam printer of FIG. 14;
[0026] FIG. 16 is a flow chart showing a size data confirming task
on a recording paper in a fourth embodiment of the image forming
apparatus according to the present invention;
[0027] FIG. 17 is a block diagram showing the structure of a test
image forming circuit provided in a fifth embodiment of the image
forming apparatus according to the present invention;
[0028] FIGS. 18A and 18B are timing charts showing operation timing
of the test image forming circuit of FIG. 17;
[0029] FIG. 19 is a view showing an output example of a test
image;
[0030] FIG. 20 is a view showing another output example of the test
image;
[0031] FIG. 21 is a view for explaining setting of a test image
forming area to a recording paper;
[0032] FIG. 22 is a flow chart showing test image forming
processing in the fifth embodiment of the image forming apparatus
according to the present invention;
[0033] FIG. 23 is a flow chart showing a series of processing
procedure from print command accepting to print processing in a
sixth embodiment of the image forming apparatus according to the
present invention;
[0034] FIG. 24 is a flow chart showing a series of processing
procedure from print command accepting to print processing in a
seventh embodiment of the image forming apparatus according to the
present invention;
[0035] FIG. 25 is a flow chart showing a series of processing
procedure from print command accepting to print processing in an
eighth embodiment of the image forming apparatus according to the
present invention;
[0036] FIG. 26 is a structural view showing a free-size cassette
used in a ninth embodiment of the image forming apparatus according
to the present invention;
[0037] FIG. 27 is a structural view showing a free-size cassette
used in a tenth embodiment of the image forming apparatus according
to the present invention;
[0038] FIGS. 28A, 28B and 28C are views showing sampling of
recording paper sizes to control a fixing device;
[0039] FIG. 29 is a flow chart showing an operation to set power
conducting ratio between main and sub heaters of the fixing device;
and
[0040] FIGS. 30A, 30B and 30C are views showing the structure of
the fixing device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] Hereinafter, the embodiments of the present invention will
be explained with reference to the accompanying drawings.
[0042] (First Embodiment)
[0043] FIG. 1 is a structural view showing the first embodiment of
an image forming apparatus according to the present invention. In
the present embodiment, as the image forming apparatus, a laser
beam printer will be explained by way of example.
[0044] As shown in FIG. 1, a laser beam printer 101 has a free-size
cassette 104 to which recording paper of an arbitrary size can be
mounted. It should be noted that the present embodiment is
structured such that a regular-size recording paper cassette (e.g.,
A4-size cassette, A3-size cassette or the like) can be also mounted
instead of the free-size cassette 104.
[0045] The free-size cassette 104 has a bottom board 129 on which
recording paper 105 is put. The bottom board 129 is structured such
that it can be turned around its trailing edge as a fulcrum
according to the number of the put recording papers 105. A cassette
type detecting unit 106 positioned on a trailing-edge side of the
free-size cassette 104 detects whether or not the free-size
cassette 104 has been mounted. The cassette type detecting unit 106
is composed of a sensor capable of detecting whether or not the
freesize cassette 104 or the regular-size recording paper cassette
(A4-size cassette or A3-size cassette) has been mounted, and also
capable of detecting the size of the regular-size recording paper
cassette. Further, a paper sensor 107 detects whether or not the
recording paper 105 has been put on the free-size cassette 104. The
paper sensor 107 is arranged above the free-size cassette 104.
[0046] The recording paper put in the free-size cassette 104 is fed
from the free-size cassette 104 one by one by driving of a pickup
roller 108, and then carried to an entrance of registration rollers
111 by paper feeding rollers 109. A paper feeding sensor 110 is
arranged between the pickup roller 108 and the paper feeding
rollers 109, and a registration sensor 112 is arranged on an
upstream side of the registration rollers 111. Therefore, by the
paper feeding sensor 110 and the registration sensor 112, it is
detected whether the recording paper has been fed or not and the
recording paper has been jammed or not.
[0047] The registration rollers 111 feed the recording paper 105 to
a path between a process cartridge 113 and a transfer roller 126 at
predetermined timing. The process cartridge 113 has a
photosensitive drum 114. A surface of the photosensitive drum 114
is charged by a charging device. Then, as a scanner unit 119
irradiates to the drum 114 a laser beam scanned in a main scan
direction, the drum 114 rotates (in sub-scan direction), whereby a
latent image is formed on the surface of the drum 114.
[0048] The scanner unit 119 has a laser beam source 122. The laser
beam generated from the laser beam source 122 is scanned in the
main scan direction and simultaneously irradiated to the
photosensitive drum 114 through a polygon mirror 120, f-.theta.
lenses 123 and a reflection mirror 124. The polygon mirror 120 is
rotatively driven by a scanner unit motor 121.
[0049] The latent image formed on the photosensitive drum 114 is
visualized as a toner image by a developing unit 113a. Then, by the
transfer roller 126, the obtained toner image on the drum 114 is
transferred onto the recording paper 105 fed by the registration
rollers 111. The recording paper 105 on which the toner image has
been transferred is carried to fixing rollers 116, and the toner
image is heat pressed onto the paper 105 by the fixing rollers 116.
A sensor 115 is arranged at an exit of the fixing rollers 116 to
detect whether or not the recording paper 105 has been jammed
between the rollers 116. By such fixing, the image is formed on the
recording paper 105. Then, the paper 105 on which the image has
been formed is externally discharged from the fixing rollers 116
through paper discharging rollers 118. A paper discharging sensor
117 is arranged at an entrance of the rollers 118 to detect whether
or not the recording paper 105 has been jammed.
[0050] A series of controlling about the image forming from the
feeding to the discharging of the paper 105 are performed by a
printer controller 128. That is, the controller 128 controls the
above image forming such that the image represented by an image
signal inputted from a video controller 103 is formed on the
recording paper 105.
[0051] The video controller 103 receives data from an external
apparatus such as a host computer 136 or the like, converts the
received data into a printer image signal (i.e., signal capable of
being processed by printer controller 128), and outputs the
converted signal to the printer controller 128. Also, the video
controller 103 captures input information corresponding to key
operating on an operation panel 127, and outputs the captured
information to the printer controller 128.
[0052] Subsequently, the main structure of a controlling system in
the laser beam printer 101 will be explained with reference to FIG.
2. FIG. 2 is the block diagram showing a main portion of the
controlling system in the laser beam printer of FIG. 1.
[0053] As shown in FIG. 2, the controlling system in the laser beam
printer 101 is connected to the host computer 136, and has the
video controller 103 which remote controls a printer engine 131 to
perform the image forming. As described above, the video controller
103 receives the data from the external apparatus such as the host
computer 136 or the like, converts the received data into the
printer image signal, captures the input information corresponding
to the key operating on the operation panel 127, and outputs the
captured information to the printer controller 128.
[0054] The printer engine 131 has a sensor group 133, the cassette
type detecting unit 106, a recording unit 132 and the printer
controller 128. The sensor group 133 includes the paper sensor 107,
the paper feeding sensor 110, the registration sensor 112 and the
like. The recording unit 132 is a general term for the free-size
cassette 104, the feeding and discharging mechanisms of the
recording paper, the process cartridge 113, the scanner unit 119,
the transfer roller 126 and the fixing rollers 116.
[0055] The printer controller 128 has a CPU 134, a ROM 138, a RAM
137, and an interface circuit 135. The CPU 134 executes calculating
and processing to control the recording unit 132 based on outputs
of the sensor group 133 and outputs of the cassette type detecting
unit 106, such that the image represented by the image signal
inputted from the video controller 103 is formed on the recording
paper 105. The ROM 138 stores a controlling program in which
controlling procedure to be executed by the CPU 134 has been
described. The RAM 137 is used as a working area in the calculating
and the processing by the CPU 134, and also temporarily stores the
data used in such the calculating and the processing. The interface
circuit 135 interfaces the video controller 103 and the CPU 134
with each other.
[0056] Subsequently, the operating procedure in case of feeding the
recording paper from the free-size cassette 104 and performing the
image forming and the control processing procedure by the printer
controller 128 will be explained with reference to FIGS. 3 to 6.
That is, FIG. 3 is the view showing an image area on the recording
paper, FIG. 4 is the view showing sampled data of recording-paper
sizes in the laser beam printer of FIG. 1, FIG. 5 is the flow chart
showing image formation processing in the laser beam printer of
FIG. 1, and FIG. 6 is the flow chart showing sampling process
procedure in a step S103 of FIG. 5.
[0057] In the laser beam printer 101, when the recording paper 105
is fed from the free-size cassette 104 and the image forming is
performed, a user previously sets the size of the paper 105 from
the operation panel 127. For example, as shown in FIG. 3, when the
recording paper 105 is carried in a direction indicated by an arrow
A, a dimension X of the paper 105 represents the size in the main
scan direction and a dimension Y represents the size in the
direction (i.e., sub-scan direction) perpendicular to the main scan
direction, and the dimensions X and Y are inputted from the
operation panel 127 by the user. In this case, the dimensions X and
Y are respectively inputted at accuracy in the units of 0.1 mm and
1 mm. For example, the inputting is performed in such a manner as X
is "123.4 mm" and Y is "123 mm". Then, data Xi and Yi respectively
representing the values of the inputted dimensions X and Y are once
captured by the video controller 103, and transferred to the CPU
134 through the interface circuit 135. The CPU 134 stores the
obtained data Xi and Yi as the size data of the recording paper 105
in the RAM 137.
[0058] As shown in FIG. 5, in the case where the recording paper is
fed from the cassette and the image forming is performed, initially
in a step S101, it is judged based on the output signal from the
cassette type detecting unit 106 whether the mounted recording
paper cassette is the free-size cassette 104 or the regular-size
recording paper cassette.
[0059] If the mounted cassette is the free-size cassette 104, the
flow advances to a step S102 to read the data Xi and Yi stored in
the RAM 137. Then, in the following step S103, sampling on the read
data Xi and Yi is performed. The details of the sampling will be
described later.
[0060] Subsequently, the flow advances to a step S104 to execute
print processing by using the data sampled in the step S103 or the
read data Xi and Yi. In this print processing, at least one of the
data sampled in the step S103 and the read data Xi and Yi are
selected for each controlling object, an operation condition on
each controlling object is set, and then each object is controlled
based on the corresponding operation condition, thereby forming the
image on the recording paper fed from the free-size cassette
104.
[0061] On the other hand, if the mounted cassette is not the
free-size cassette 104 but is the regular-size recording paper
cassette, the flow advances to a step S105. In the step S105, the
type of the recording paper cassette, i.e., the size of the
recording paper put in such the cassette is detected based on the
output signal from the cassette type detecting unit 106. In this
case, e.g., if the mounted cassette is the A4 type recording paper
cassette, the size of the recording paper is recognized as the A4
size. In the following step S104, the print processing is performed
based on the recording paper size recognized in the step S105. This
print processing is the same as the conventional print processing
performed according to the regular-size recording paper size.
[0062] Subsequently, the sampling in the step S103 will be
explained with reference to FIGS. 4 and 6.
[0063] In the set recording paper size, size data in its main scan
direction and size data in its sub-scan direction have been sampled
according to the controlling object, and relationship between the
sampled data and the controlling object has been previously
defined.
[0064] For example, as shown in FIG. 4, the dimension X in the main
scan direction is sampled into data Xsl for fixing device
controlling and the dimension Y in the sub-scan direction is
sampled into data Ys1 for recording paper conveying controlling. By
such the data sampling, the data Xsl is classified into four groups
of 170 mm, 200 mm, 240 mm and 270 mm. On the other hand, the data
Ys1 is classified into a group in the unit of 1 mm.
[0065] The sampling procedure will be explained by using an example
that the data Xi in the main scan direction is sampled into the
data Xsl. As shown in FIG. 6, it is initially judged in a step S110
whether or not the set data Xi is larger than 170 mm. Then, if a
formula Xi>170 mm is not satisfied, the sampled data Xsl is set
at 150 mm in a step S111.
[0066] On the other hand, if the formula Xi>170 mm is satisfied,
the flow advances to a step S112 to judge whether or not the data
Xi is larger than 200 mm. Then, if a formula Xi>200 mm is not
satisfied, it is judged that a formula 170 <Xi<200 is
satisfied, and thus the sampled data Xsl is set at 200 mm in a step
S113.
[0067] On the other hand, if the formula Xi>200 mm is satisfied,
the flow advances to a step S114 to judge whether or not the data
Xi is larger than 240 mm. Then, if a formula Xi>240 mm is not
satisfied, it is judged that a formula 200<Xi.ltoreq.240 is
satisfied, and thus the sampled data Xsl is set at 240 mm in a step
S115.
[0068] If the formula Xi>240 mm is satisfied, the flow advances
to a step S116 to set the sampled data Xsl at 270 mm.
[0069] As above, when the value of the sampled data Xsl is set, it
is considered that the data Xi has been sampled, whereby the
processing terminates.
[0070] By the sampling in the same manner as above, the sampled
data Ys can be obtained.
[0071] Subsequently, a method to use the sampled data in each
controlling object will be explained.
[0072] Initially, the controlling to the fixing device will be
explained with reference to FIGS. 28A to 28C and FIG. 29.
[0073] By the way, FIG. 30A shows the structure of the fixing
device in the image forming apparatus. As shown in FIG. 30A, a
thermistor 802 is provided in the vicinity of the fixing rollers
116 to detect surface temperature of the roller 116. Further, two
heaters of which heating areas are different from each other are
respectively provided in the rollers 116. That is, one is a main
heater 803 to heat a central portion of the roller 116 and the
other is a sub-heater 804 to heat both-side portions thereof (FIGS.
30B and 30C).
[0074] Since the thermistor 802 is in contact with the fixing
roller 116, the thermistor 802 is set at a position through which
the recording paper does not pass, to prevent influence on the
image due to friction of the contacted portion or the like. For
this reason, the setting position of the thermistor 802 is close to
the sub-heater 804.
[0075] Further, since the thermistor 802 is connected to the CPU
134, power conducting to each heater is controlled by the CPU 134
such that the fixing device has predetermined temperature.
[0076] Subsequently, a method to control the heaters will be
explained.
[0077] Although the two heaters, i.e., the main heater 803 and the
sub-heater 804 are provided in the fixing rollers 116, both the
heaters are not turned on or off at once. That is, by the
controlling of the CPU 134, power conducting ratio to the main
heater 803 and the sub-heater 804 is changed according to the size
of the recording paper.
[0078] Thus, a temperature distribution of the fixing rollers 116
in a longitudinal direction can be made uniform. Such the method is
especially effective in a case where the fixing roller (e.g., of
which core-metal is thin) of which heat capacity is small is
used.
[0079] Then, a method to set the power conducting ratio to the main
heater 803 and the sub-heater 804 will be explained. As shown in
FIG. 28A, the recording paper of the regular-size recording paper
cassette is classified by the CPU 134 into four groups of Group 1,
Group 2, Group 3 and Group 4. In FIG. 28A, a symbol "P" of "A4-P"
means "portrait", and represents the A4 recording paper which is
set in the cassette to be fed in a longitudinal (longer-side)
direction. Further, a symbol "L" of "A4-L" means "landscape", and
represents the A4 recording paper which is set in the cassette to
be fed in a lateral (shorter-side) direction.
[0080] FIG. 28C shows the power conducting ratio each corresponding
to each group. For example, in case of feeding the recording paper
of A3-P size, the main heater 803 and the sub-heater 804 are
controlled at the conducting ratio of 500:400. These groups have
been classified and set according to the length of the recording
paper in the longitudinal direction of the roller 116.
[0081] Further, as shown in FIG. 28B, the recording paper of the
free-size cassette is classified by the CPU 134 into four groups of
Group 1, Group 2, Group 3 and Group 4. Like the regular-size
recording paper cassette, the power conducting ratio is controlled
according to the correspondence shown in FIG. 28C. For example, in
a case where the sampled data Xsl obtained by the operating shown
in the flow chart of FIG. 6 corresponds to 240 mm, such the
recording paper is classified as the Group 2, whereby the heaters
803 and 804 are controlled at the conducting ratio of 500:250.
[0082] Subsequently, a method to set the power conducting ratio to
the heaters will be explained with reference to a flow chart shown
in FIG. 29. This flow chart shows the operation common to the
regular-size recording paper cassette and the free-size
cassette.
[0083] Initially, in a step S701, the classification of the
recording paper for the fixing device controlling is checked. In
case of feeding the paper from the regular-size cassette, it is
checked based on FIG. 28A which of the Groups 1 to 4 the
classification of the recording paper belongs to. On the other
hand, in case of feeding the paper from the free-size cassette, it
is checked based on FIG. 28B which of the Groups 1 to 4 the
classification of the recording paper belongs to. Then, in a step
S702, if it is judged that the classification belongs to the Group
4, the power conducting ratio to the main heater and the sub-heater
is set at 500:0 in a step S703. On the other hand, if it is judged
that the classification does not belong to the Group 4 in the step
S702, the flow advances to a step S704. Then, if it is judged that
the classification belongs to the Group 3 in the step S704, the
power conducting ratio is set at 500:100 in a step S705. On the
other hand, if it is judged that the classification does not belong
to the Group 3 in the step S704, the flow advances to a step S706.
Then, if it is judged that the classification belongs to the Group
2 in the step S706, the power conducting ratio is set at 500:250 in
a step S707. On the other hand, if it is judged that the
classification does not belong to the Group 2 in the step S706, it
is considered that the classification belongs to the Group 1, and
thus the conducting ratio is set at 500:400 in a step S708.
[0084] As above, the size of the free-size sheet cassette is
converted to be matched with the controlling which is performed for
the regular-size cassette. Therefore, even in case of feeding the
sheet from the free-size cassette, the controlling can be performed
in the same manner as in case of feeding the sheet from the
regular-size recording paper cassette. For this reason, even in
case of feeding the sheet from the free-size cassette, since the
controlling according to the rendered size can be performed, there
is no need to add any complicated program for the fixing device
controlling, thereby shortening a developing period and saving
developing costs.
[0085] Subsequently, the controlling of the recording paper
conveying will be explained with reference to FIG. 9. FIG. 9 shows
operation timing in the controlling of the recording paper
conveying at the printing by the laser beam printer in FIG. 1.
Concretely, the operation timing of the paper feeding sensor 110,
the paper feeding rollers 109, the registration sensor 112 and the
registration rollers 111 at the printing will be explained.
[0086] In the laser beam printer 101, the series of controlling for
the recording paper conveying are performed according to the
dimension Y of the recording paper in the sub-scan direction. In
the present embodiment, the controlling of the recording paper
conveying is performed based on the data Ys1 sampled in the unit of
1 mm shown in FIG. 4. For example, in the printing, one sheet of
the recording paper 105 is initially fed from the free-size
cassette 104 by the driving of the pickup roller 108. When one
sheet of the paper 105 is fed from the cassette 104, the paper
feeding sensor is turned on (timing (1)). In response to this, the
paper feeding rollers 109 are driven (timing (2)), whereby the
paper 105 is fed to the registration rollers 111.
[0087] When the leading edge of the paper 105 passes through the
registration sensor 112, the sensor 112 is turned on (timing (3)).
The paper 105 is further fed until its leading edge runs into the
registration rollers 111. When the leading edge runs into the
rollers 111, the conveying of the recording paper 105 is
stopped.
[0088] Then, the driving of the registration rollers 111 is started
at predetermined timing (timing (4)), and the recording paper 105
is fed to the process cartridge 113. After then, a trailing edge of
the paper 105 passes through the paper feeding sensor 110, and the
sensor 110 is turned off (timing (5)). After elapsing a
predetermined time from the turning off of the sensor 110, the
driving of the paper feeding rollers 109 is stopped.
[0089] If a predetermined time from the start of the conveying by
the registration rollers 111 to the turning off of the paper
feeding sensor 110 is assumed as a time .phi., this predetermined
time .phi. is determined by the dimension Y of the paper 105 in the
sub-scan direction (i.e., paper conveying direction). Therefore,
abnormality such as paper jamming or the like in the recording
paper conveying can be detected by observing the predetermined time
.phi.. Such detecting of the abnormality in the paper conveying is
performed by comparing a predetermined time calculated from the
data Ys1 sampled in the unit of 1 mm and the predetermined time
.phi. in the actual printing.
[0090] As above, by controlling the recording paper conveying based
on the data Ys1 sampled at a level of 1 mm, the optimum recording
paper conveying according to the size of the paper 105 can be
performed. Therefore, an optimum throughput for each recording
paper size can be obtained, and also the abnormality in the
recording paper conveying can be accurately detected.
[0091] Subsequently, the image area controlling wherein the area of
the image formed on the recording paper is controlled will be
explained with reference to FIGS. 7 and 8.
[0092] In the image area controlling, unlike the above fixing
device controlling, the dimension of the recording paper in the
main scan direction is considered as the dimension X, and the data
Xi inputted from the control panel 127 is used as it is.
[0093] FIG. 7 is the block diagram showing the structure of an
image area controlling circuit provided in the printer controller
of the laser beam printer in FIG. 1, and FIG. 8 is the timing chart
showing operation timing in the image area controlling circuit in
FIG. 7.
[0094] As shown in FIG. 7, an image area controlling circuit 151 is
used for the image area controlling. The image area controlling
circuit 151 has an image buffer circuit 153. The image buffer
circuit 153 further has a circuit which stores and latches an image
signal VIDEO 1 of one line sent from the video controller 103 in
synchronism with an image clock VCLK from an image clock generator
(OSC) 155. The latching of the image signal is controlled based on
an output signal HSYNC of a counter 152 (i.e., output signal from
NOR circuit 156). Further, an image signal VIDEO 2 of one line is
outputted from the image buffer circuit 153 to the recording unit
132 in synchronism with the image clock VCLK.
[0095] The counter 152 has a down counter which counts a count
value rendered from the CPU 134 through a latch circuit 154, based
on the image clock VCLK from the image clock generator (OSC) 155.
The count value rendered from the CPU 134 consists of the value
corresponding to the dimension Xi of the paper in the main scan
direction inputted from the operation panel. A horizontal
synchronization signal BD outputted from a laser beam detecting
device 157 in the scanner unit 119 is inputted to the counter 152
as a load pulse, and the count value is preset responsive to the
inputting of the load pulse. The output from the counter 152 is NOR
operated by the NOR circuit 156, and then the signal HSYNC is
outputted from the NOR circuit 156.
[0096] Subsequently, the operation timing of the image area
controlling circuit 151 will be explained with reference to FIG.
8.
[0097] It is assumed that the data Xi is read from the RAM 137 in
the printer controller 128 by the CPU 134 and the count value
corresponding to the data Xi is outputted to the counter 152
through the latch circuit 154. In this case, if the laser beam
detecting device 157 detects the laser beam and inputs the
horizontal synchronization signal BD to the counter 152 as the load
pulse, the count value corresponding to the sampled data Xi is
preset to the counter 152, and simultaneously the output signal
HSYNC from the NOR circuit 156 becomes low level, whereby the reset
of the counter 152 is released.
[0098] When the reset is released, the counter 152 starts countdown
in response to a fall of the image clock VCLK. After starting the
countdown, when the counting of the set count value is performed,
the output signal HSYNC from the NOR circuit 156 becomes high
level. Therefore, the image signal VIDEO 2 of one line latched in
the image buffer circuit 153 is outputted to the recording unit 132
in synchronism with the image clock VCLK. Further, the counter 152
is reset until the next horizontal synchronization signal BD is
inputted.
[0099] The counting operation by the counter 152 is repeated for
image lines of one page. Thus, the predetermined image area
corresponding to the recording paper size is formed by such the
repeated operations.
[0100] As explained above, in the present embodiment, the sampling
different for each controlling object is performed and then the
controlling objects are controlled respectively according to the
sampled results. Therefore, the controlling suitable for the sheet
size of the free-size cassette can be performed without lowering
the throughput and complicating the controlling itself.
[0101] (Second Embodiment)
[0102] Subsequently, the second embodiment of the present invention
will be explained with reference to FIGS. 10 to 13. FIG. 10 is the
block diagram showing a main portion of a controlling system in the
second embodiment of the image forming apparatus according to the
present invention, and FIG. 11 is the flow chart showing a data
writing task to an NVRAM (Non-Volatile Random Access Memory) in a
laser beam printer of FIG. 10, FIG. 12 is the flow chart showing a
data reading task from the NVRAM in the laser beam printer of FIG.
10, and FIG. 13 is the flow chart showing the data reading task
from the NVRAM in a case where plural kinds of free-size cassettes
are mounted to the laser beam printer of FIG. 10. The NVRAM
consists of an EEPROM (Electrically Erasable Programmable Read-Only
Memory), a flash ROM, a battery-backup memory or the like.
[0103] The present embodiment is different from the first
embodiment in the point that an NVRAM 201 is provided to store a
size of a designated recording paper. However, other components in
the present embodiment are substantially the same as those in the
first embodiment, whereby the explanation thereof is omitted. It
should be noted that, as a matter of convenience, the same
components as those in FIG. 1 are added with the same reference
numerals.
[0104] In the present embodiment, as shown in FIG. 10, the size of
a recording paper 105 inputted from a host computer 136 or an
operation panel 127 is stored in the NVRAM 201, mounting of a
free-size cassette 104 is detected based on an output signal from a
cassette type detecting unit 106, and the size of the recording
paper stored in the NVRAM 201 is read. In this case, if the
recording paper size is not stored in the NVRAM 201, it notifies
the host computer 136 of such a fact or it displays such the fact
on a display unit of the operation panel 127.
[0105] Subsequently, the data writing task to the NVRAM 201 in the
present embodiment will be explained with reference to FIG. 11.
[0106] When the size of the recording paper 105 is inputted from
the host computer 136, a recording paper size designating screen is
initially displayed, and a value of the designated recording paper
size is inputted on the screen. In this case, it has been set to
enable a user to input the value of the designated recording paper
size in the unit of 1 mm or 0.1 mm.
[0107] When the value of the designated recording paper size is
inputted, size data representing the input value is transferred to
a printer controller 128 through a video controller 103.
[0108] As shown in FIG. 11, a CPU 134 in the printer controller 128
initially receives the size data in a step S201, and then writes
the received data at a defined address of the NVRAM 201 in a step
S202.
[0109] Subsequently, the data reading task from the NVRAM 201 will
be explained with reference to FIG. 12.
[0110] Initially, in a step S203, the output signal from the
cassette type detecting unit 106 is captured to detect the size of
the mounted recording paper cassette. Then, it is judged in a step
S204 whether or not the mounted cassette is a free-size cassette
104. If the mounted cassette is not the free-size cassette 104 but
is a regular-size recording paper cassette, the flow advances to a
step S205 to execute ordinary print processing. After then, the
processing terminates.
[0111] On the other hand, if the mounted cassette is the free-size
cassette 104, the flow advances to a step S206 to read the size
data stored at the defined address of the NVRAM 201. Then, it is
judged in a step S207 whether or not the size data has been stored
at the defined address of the NVRAM 201.
[0112] If the size data has been stored at the defined address of
the NVRAM 201, the flow advances to a step S209 to perform sampling
on the read size data in the same manner as that in the first
embodiment, and perform the print processing by using sampled data.
After then, the processing terminates.
[0113] On the other hand, if the size data has not been stored at
the defined address of the NVRAM 201, it is considered that the
recording paper size of the freesize cassette 104 is not yet
designated, and the flow advances to a step S208 to perform error
processing. In the error processing, it notifies the host computer
136 of the fact that there is no size data of the recording paper.
The host computer 136 which received such a notification displays
the contents thereof. It should be noted that, when the size data
is designated from the operation panel 127, it is possible to
display on the operation panel 127 that there is no size data.
[0114] Since there are the plural kinds of free-size cassettes, for
example, one can be changed to another in case of using these
cassettes. In such a case of using the plural free-size cassettes
by turns, the size data of the designated recording paper is
correlated with each free-size cassette and stored in the NVRAM
201, and then the size data correlated with the mounted free-size
cassette 104 is read out. Projections which constitute a detection
code are provided on the plural kinds of free-size cassettes. These
projections are rearranged (or recomposed) in different manner
according to the kind of the cassette. Since the output signal from
the cassette type detecting unit 106 for each free-size cassette is
different according to a difference in such the rearrangement of
the projections, each free-size cassette can be discriminated based
on such the output signal. For the discriminating, appropriate
identification has been previously allocated to each cassette. For
example, if the output signal from the cassette type detecting unit
106 represents "1", it represents the cassette of "SIZE 1". On the
other hand, if the output signal represents "0", it represents the
cassette of "SIZE 2".
[0115] It will be explained, with reference to FIG. 13, the data
reading task from the NVRAM 201 in the above case where the size
data of the designated recording paper has been correlated with
each free-size cassette and stored in the NVRAM 201. The processing
in this case is substantially the same as that in FIG. 12.
Therefore, the same steps as those in FIG. 12 are added with the
same numbers, and the explanation thereof is omitted. Hereinafter,
the steps different from the case of FIG. 12 will be explained.
[0116] In a step S210, the type (or kind) of the free-size cassette
is detected based on the output signal from the cassette type
detecting unit 106. For example, if the cassette of SIZE 1 is
detected, the flow advances to a step S211 to read from the NVRAM
201 the size data correlated with the free-size cassette of SIZE 1.
On the other hand, if the cassette of SIZE 2 is detected, the flow
advances to a step S212 to read the size data correlated with the
free-size cassette of SIZE 2.
[0117] Therefore, the operation and working to designate the size
of the recording paper which should be performed every time the
free-size cassette is mounted can be simplified.
[0118] (Third Embodiment)
[0119] Subsequently, the third embodiment of the present invention
will be explained with reference to FIGS. 14 and 15. FIG. 14 is the
structural view showing the third embodiment of the image forming
apparatus according to the present invention, and FIG. 15 is the
block diagram showing a main portion of a controlling system in a
laser beam printer of FIG. 14.
[0120] The present embodiment is different from the second
embodiment in the point that an NVRAM 202 storing a size of a
designated recording paper is provided on a free-size cassette 104.
However, other components in the present embodiment are
substantially the same as those in the first embodiment, whereby
the explanation thereof is simplified or omitted.
[0121] Concretely, as shown in FIGS. 14 and 15, the NVRAM 202
storing the size of the designated recording paper is provided on a
side wall of the free-size cassette 104, and the NVRAM 202 is
connected to a CPU 134 through a connector (not shown) attached to
the NVRAM 202.
[0122] Since the present embodiment is different from the second
embodiment in only the point that the NVRAM 202 storing the size of
the designated recording paper is provided on the free-size
cassette 104, a data writing task to the NVRAM 202 and a data
reading task from the NVRAM 202 are performed in the same procedure
as that in the second embodiment.
[0123] (Fourth Embodiment)
[0124] Subsequently, the fourth embodiment of the present invention
will be explained with reference to FIG. 16. FIG. 16 is the flow
chart showing a confirming task on size data of a recording paper
in the fourth embodiment of the image forming apparatus according
to the present invention.
[0125] Since the present embodiment has the same hardware structure
as that in the second embodiment, the same components as those in
the second embodiment are added with the same reference numerals
and the explanation thereof is omitted. In the present embodiment,
the size data of the recording paper stored in an NVRAM 201 is read
out according to a size request command sent from an operation
panel 127, and the read data is displayed on the operation panel
127. Alternatively, the size data of the recording paper stored in
the NVRAM 201 is read out according to a size request command sent
from a host computer 136, and the read data is notified to the
computer 134.
[0126] In FIG. 16, in a step S213, when the size request command
sent from the host computer 136 or the operation panel 127 through
a video controller 103 is received, the size data stored at a
defined address of the NVRAM 201 is read out in a step S214.
[0127] Then, the flow advances to a step S215 to judge whether or
not the recording paper size data for the free-size cassette 104
has been stored. If stored, the flow advances to a step S217 to
send the read size data to the video controller 103. On the other
hand, if not stored, the flow advances to a step S216 to send the
video controller 103 information representing that the size data
has not been stored (to be referred as "size data absent data"
hereinafter).
[0128] Procedure to send such the size data or the size data absent
data will be explained. According to a status request from the
video controller 103, a CPU 134 loads such the size data or the
size data absent data to its serial signal port. The video
controller 103 detects the loading of the size data or the size
data absent data from the CPU 134, sends a serial clock, and
receives the size data or the size data absent data from the serial
signal port of the CPU 134. When the size data or the size data
absent data is received, the video controller 103 displays such a
result on the operation panel 127. On the other hand, if the size
request command is sent from the host computer 136, the video
controller 103 transmits such the result to the host computer
136.
[0129] As a result, a user can easily confirm the size data of the
recording paper stored in the NVRAM 201.
[0130] In the present embodiment, it has been explained the example
that the size data of the recording paper has been stored in the
NVRAM 201. However, it is possible to store the size data in
another storing means and then read it from such the means.
[0131] (Fifth Embodiment) Subsequently, the fifth embodiment
according to the present invention will be explained with reference
to FIGS. 17 to 22. FIG. 17 is the block diagram showing the
structure of a test image forming circuit provided in the fifth
embodiment of the image forming apparatus according to the present
invention, FIGS. 18A and 18B are the timing charts showing
operation timing of the test image forming circuit of FIG. 17, FIG.
19 is the view showing an output example of a test image, FIG. 20
is the view showing another output example of the test image, FIG.
21 is the view for explaining setting of a test image forming area
onto a recording paper, and FIG. 22 is the flow chart showing test
image forming processing in the fifth embodiment of the image
forming apparatus according to the present invention. It should be
noted that, as a matter of convenience, the same components as
those in FIG. 1 are added with the same reference numerals.
[0132] In the present embodiment, when a recording paper size of a
free-size cassette 104 is designated, it is performed the test
image forming processing wherein the test image having an image
area defined by the designated recording paper size is formed on a
recording paper 105 fed from the free-size cassette 104.
[0133] This test image is the image which has the image area
obtained in consideration of a predetermined margin for the
designated recording paper size. For example, as shown in FIG. 19,
if the designated size coincides with the size of a recording paper
360 actually fed from the free-size cassette 104, a test image 361
having the image area defined by this designated size is formed on
the recording paper 360 in the state that the predetermined margin
is provided on the paper 360. However, as shown in FIG. 20, if the
designated size is smaller than the size of a recording paper 362
actually fed from the cassette 104, a test image 363 having the
image area defined by this designated size is formed on the paper
362 in the state that a predetermined margin is provided on the
paper 362.
[0134] The test image is formed by the test image forming circuit.
As shown in FIG. 17, the test image forming circuit is composed of
a CPU 134 to control the test image forming and also control
printing of the formed test image on the recording paper, a
sub-scan counter unit 305 including a counter to count a length in
a recording paper conveying direction (i.e., sub-scan direction),
and a main scan counter unit 310 including a counter to count a
length in a laser beam scanning direction (i.e., main scan
direction).
[0135] A selector unit 303 is connected to the CPU 134 through an
address bus 301. The selector unit 303 decodes an address inputted
from the CPU 134 through the address bus 301, and generates select
signals 306, 321, 322 and 323 respectively to comparator units 307,
308, 311 and 313. Thus, the comparator units 307, 308, 311 and 313
are arranged on an address map of the CPU 134, and comparison data
is set to each of the comparator units 307, 308, 311 and 313 by the
CPU 134 through a data bus 302.
[0136] In the comparator unit 308, the number of pulses of a BD
signal 304 corresponding to a distance from a leading edge of the
recording paper to a start position of image writing is set as the
comparison data. The comparator unit 308 compares an output of the
sub-scan counter unit 305 with data set by the CPU 134, and outputs
a signal 317 when the output of the counter unit 305 coincides with
the data set by the CPU 134.
[0137] In the comparator unit 307, the number of pulses of the BD
signal 304 corresponding to the distance from the recording paper
leading edge to an end position of the image writing is set as the
comparison data. The comparator unit 307 compares the output of the
sub-scan counter unit 305 with the data set by the CPU 134, and
outputs a signal 318 when the output of the unit 305 coincides with
the data set by the CPU 134.
[0138] The sub-scan counter unit 305 captures through an inverter
the BD signal 304 generated every scanning of the laser beam, and
counts the captured signal. Resetting to the sub-scan counter unit
305 is controlled responsive to a rest signal 341 from the CPU 134.
Concretely, the CPU 134 holds the reset signal 341 true until the
recording paper leading edge reaches a predetermined position to
stop the counting of the sub-scan counter unit 305. Then, when the
recording paper leading edge reaches the predetermined position,
the CPU 134 sets the reset signal 341 false such that the resetting
is released, to start the operating of the sub-scan counter unit
305.
[0139] In the comparator unit 313, the number of image clocks 312
corresponding to the distance from the BD signal 304 to the start
position of the image writing is set as the comparison data. The
comparator unit 313 compares the output of the main scan counter
unit 310 with the data set by the CPU 134, and outputs a signal 319
when the output of the unit 310 coincides with the data set by the
CPU 134.
[0140] In the comparator unit 311, the number of image clocks 312
corresponding to the distance from the BD signal 304 to the end
position of the image writing is set as the comparison data. The
comparator unit 311 compares the output of the main scan counter
unit 310 with the data set by the CPU 134, and outputs a signal 320
when the output of the unit 310 coincides with the data set by the
CPU 134.
[0141] The main scan counter unit 310 counts the image clocks 312
of one pixel. Further, by using the BD signal 304 as a reset
signal, the unit 310 is reset every time the BD signal 304 becomes
true.
[0142] The output signal 317 from the comparator unit 308 is
inputted to an S terminal of an S/R latch circuit 309, the output
signal 318 from the comparator unit 307 is inputted to an R
terminal of the circuit 309, the output signal 319 of the
comparator unit 313 is inputted to an S terminal of an S/R latch
circuit 314, and the output signal 320 from the comparator unit 311
is inputted to an R terminal of the circuit 314.
[0143] Output signals 344 and 349 respectively outputted from the
S/R latch circuits 309 and 314 are captured by an AND gate 316. The
AND gate 316 performs logical operations on the output signals 344
and 349, and outputs the operation result as a video signal
315.
[0144] Such the test image forming circuit as structured above
outputs the signals at the timing shown in FIGS. 18A and 18B.
[0145] For example, as shown in FIG. 18A, when the leading edge of
the recording paper reaches the predetermined position, the false
reset signal 341 is rendered from the CPU 134 to the sub-scan
counter unit 305, and the counter unit 305 starts counting. The
comparator unit 308 compares the number of pulses of the BD signal
304 corresponding to the distance from the paper leading edge to
the start position of the image writing with the output of the
sub-scan counter unit 305, and outputs the signal 317 when the
number of pulses coincides with the output from the counter unit
305. According to the outputting of this signal 317, the S/R latch
circuit 309 holds the outputting of the signal 344, and this signal
344 is inputted to the AND gate 316. The comparator unit 307
compares the number of pulses of the BD signal 304 corresponding to
the distance from the paper leading edge to the end position of the
image writing with the output of the sub-scan counter unit 305, and
outputs the signal 318 when the number of pulses coincides with the
output from the counter unit 305. According to the outputting of
this signal 318, the S/R latch circuit 309 stops outputting the
signal 344. When the paper leading edge reaches the predetermined
position, the false rest signal 341 is rendered from the CPU 134 to
the sub-scan counter unit 305, and thus the counter unit 305 stops
counting.
[0146] On the other hand, as shown in FIG. 18B, when the resetting
is released responsive to the BD signal 304, the main scan counter
unit 310 starts counting the image clocks 312 of one pixel. The
comparator unit 313 compares the number of image clocks 312
corresponding to the distance from the BD signal 304 to the start
position of the image writing with the output from the main scan
counter unit 310, and outputs the signal 319 when the number of
image clocks 312 coincides with the output from the counter unit
310. According to the outputting of this signal 319, the SIR latch
circuit 314 holds the outputting of the signal 349, and this signal
349 is inputted to the AND gate 316. The comparator unit 311
compares the number of image clocks 312 corresponding to the
distance from the BD signal 304 to the end position of the image
writing with the output from the main scan counter unit 310, and
outputs the signal 320 when the number of image clocks 312
coincides with the output from the counter unit 310. According to
the outputting of this signal 320, the S/R latch circuit 314 stops
outputting the signal 349. When the BD signal 304 becomes true, the
main scan counter unit 310 is rest.
[0147] From an output terminal of the AND gate 316 which inputted
the above signals, it can be obtained the video signal 315 which
turns on a laser beam source 122 according to the width of the
recording paper every scanning of the laser beam, and repeats such
lighting of the laser beam according to the length of the recording
paper.
[0148] Subsequently, the data which is set to each of the
comparator units 307, 308, 311 and 313 by the CPU 134 will be
explained with reference to FIG. 21. In the explanation, it is used
the drawing which conceptionally shows a BD signal 370 and a
position of a recording paper 381 to clarify the correspondence of
the BD signal to the recording paper position.
[0149] The recording paper 381 premises that a line (paper-through
standard line) 371 representing a central position of the paper is
used as a standard of a paper-through position. Further, a value A
shown by a dimensional line 379 represents a dimension of the
recording paper 381 in the main scan direction, and a value B shown
by a dimensional line 377 represents a dimension of the paper 381
in the sub-scan direction. These values A and B are set by the
user. Further, a value a shown by a dimensional line 376 represents
a predetermined image margin, and a value C shown by a line 374
represents a distance corresponding to a time of laser beam
scanning from the BD signal 370 to the paper-through standard line
371.
[0150] Since the data to be set to the comparator unit 313
represents the number of image clocks 312 corresponding to the
distance from the BD signal 370 to the start position of the image
writing, the time from the BD signal 370 to the start position of
the image writing is represented by a value D shown by a
dimensional line 373. The value D is calculated by a following
equation (1).
D=C-{(A/2)-a}/V1s (1)
[0151] V1s: scanning speed of laser beam
[0152] It should be noted that the data actually set to the
comparator unit 313 has the value obtaining by dividing the
calculated value D by the period of the image clock 312.
[0153] Since the data to be set to the comparator unit 311
represents the number of image clocks 312 corresponding to the
distance from the BD signal 370 to the end position of the image
writing, the time from the BD signal 370 to the end position of the
image writing is represented by a value E shown by a dimensional
line 372. The value E is calculated by a following equation
(2).
E=C+{(A/2)-a}/V1s (2)
[0154] It should be noted that the data actually set to the
comparator unit 311 has the value obtaining by dividing the
calculated value E by the period of the image clock 312.
[0155] Since the data to be set to the comparator unit 308
represents the number of pulses of the BD signal 370 corresponding
to the distance from the recording paper leading edge to the start
position of the image writing, the distance from the leading edge
of the paper 381 to the start position of the image writing is
represented by the value a. Therefore, a time t0 is calculated by
dividing the value a by recording paper conveying speed Vs, and the
time t0 is further divided by a pulse interval of the BD signal
370. The obtained value corresponds to the data to be set to the
comparator unit 308.
[0156] Since the data to be set to the comparator unit 307
represents the number of pulses of the BD signal 370 corresponding
to the distance from the recording paper leading edge to the end
position of the image writing, the distance from the leading edge
of the paper 381 to the end position of the image writing has a
value F shown by a dimensional line 378. Therefore, a time te is
calculated by dividing the value F by the recording paper conveying
speed Vs, and the time te is further divided by the pulse interval
of the BD signal 370. The obtained value corresponds to the data to
be set to the comparator unit 307. This distance (value) F is
obtained by subtracting the value a from the set dimension (value)
B.
[0157] Subsequently, processing procedure of the CPU 134 in the
test image forming circuit will be explained with reference to FIG.
22.
[0158] Initially, in a step S300, the true reset signal 341 is
outputted to reset the sub-scan counter unit 305.
[0159] Subsequently, in a step S301, the number of image clocks 312
corresponding to distance from the start position of main scan
writing, i.e., the BD signal 304, to the start position of the
image writing is calculated. Then, in a step S302, the number of
image clocks 312 obtained by the calculating is set to the
comparator unit 313. The method to calculate such the value to be
set was described as above.
[0160] Subsequently, in a step S303, the number of image clocks 312
corresponding to the distance from the end position of the main
scan writing, i.e., the BD signal 304, to the end position of the
image writing is calculated. Then, in a step S304, the number of
image clocks 312 obtained by the calculating is set to the
comparator unit 311. The method to calculate such the value to be
set was described as above.
[0161] Subsequently, in a step S305, the number of pulses of the BD
signal 304 corresponding to the distance from the start position of
sub-scan writing, i.e., the recording paper leading edge, to the
start position of the image writing is calculated. Then, in a step
S306, the number of pulses of the BD signal 304 obtained by the
calculating is set to the comparator unit 308. The method to
calculate such the value to be set was described as above.
[0162] Subsequently, in a step S307, the number of pulses of the BD
signal 304 corresponding to the distance from the end position of
the sub-scan writing, i.e., the recording paper leading edge, to
the end position of the image writing is calculated. Then, in a
step S308, the number of pulses of the BD signal 304 obtained by
the calculating is set to the comparator unit 307. The method to
calculate such the value to be set was described as above.
[0163] Subsequently, in a step S309, it is controlled to start the
paper conveying. Then, it is judged in a step S310 whether or not
the recording paper leading edge reaches the printing start
position. If the leading edge reaches the start position, the flow
advances to a step S311. In the step S311, the false reset signal
is outputted to release the resetting of the sub-scan counter unit
305. By this reset signal, the resetting of the sub-scan counter
unit 305 is released, and thus the counter unit 305 starts
counting.
[0164] In a step S312, it is judged whether or not the printing on
one recording paper terminates. If the printing on one recording
paper terminates, the flow advances to a step S313 to output the
true reset signal to reset the sub-scan counter unit 305, and the
processing terminates. By this reset signal, the subscan counter
unit 305 is reset, and thus the unit 305 stops counting.
[0165] As above, when the recording paper size of the free-size
cassette 104 is designated, it is performed the test image forming
processing wherein the test image having the image area defined by
the designated recording paper size is formed on the recording
paper fed from the free-size cassette 104. Therefore, the user can
easily confirm whether or not the recording paper size previously
designated coincides with the actual recording paper size, whereby
the wasteful outputting due to designation error of the recording
paper size or the like can be avoided in advance.
[0166] (Sixth Embodiment)
[0167] Subsequently, the sixth embodiment of the present invention
will be explained with reference to FIG. 23. FIG. 23 is the flow
chart showing a series of processing procedure from print command
receiving to print processing in the sixth embodiment of the image
forming apparatus according to the present invention.
[0168] The present embodiment has the same structure as that in the
first embodiment. However, in the present embodiment, when it is
judged that a size of a recording paper to be fed is not yet
determined, controlling is performed such that paper feeding is not
performed but misprint processing is performed. It should be noted
that, as a matter of convenience, the same components as those in
FIG. 1 are added with the same reference numerals.
[0169] In order to determine the size of the recording paper to be
fed, as described in the first embodiment, in case of using a
regular-size recording sheet cassette, when the cassette is
mounted, the size of the recording paper put in this cassette is
detected and determined by a cassette type detecting unit 106.
However, in case of using a free-size cassette 104 in which it is
difficult to designate the recording paper size by a contact
switch, it is necessary to previously designate the recording paper
size from an operation panel 127 or a host computer 136 through a
video controller 103. When the free-size cassette 104 is mounted
and the paper size is designated, the size of the recording paper
to be fed is determined. Similarly, if there is no paper size
detecting unit such as a multi-paper tray, it is necessary to
previously designate the size of the recording paper to be fed.
[0170] As above, a method to determine the recording paper size is
different according to a difference of a paper feeding method. In
the present embodiment, it is first judged whether or not the
recording paper size has been determined, and the processing is
controlled according to a judged result. This control processing
procedure will be explained with reference to FIG. 23.
[0171] Initially, it waits for a print command in a step S400. If
the print command is received, the flow advances to a step S401 to
judge whether or not the recording paper size has been determined.
Such the judging is performed based on a processed result of
another task, i.e., a recording paper size determining task. In the
recording paper size determining task, as described above, on the
regular-size recording paper cassette, it is judged based on an
output signal of the cassette type detecting unit 106 whether or
not a recording paper size designating condition has been obtained.
On the free-size cassette 104, it is judged based on the output
signal of the unit 106 and presence/absence of the paper size
designating whether or not the recording paper size designating
condition has been obtained. On the multi-paper tray, it is judged
based on presence/absence of the paper size designating whether or
not the recording paper size designating condition has been
obtained. If the recording paper size designating condition has
been obtained, the recording size is determined based on the
obtained condition and also a flag representing such the
determination is set.
[0172] If the recording paper size has been determined, the flow
advances to a step S402 to perform the controlling such that the
print processing starts. In the print processing, if the recording
paper size has been designated as in case of using the free-size
cassette 104, like the first embodiment, the adaptive controlling
is performed based on the designated recording paper size. On the
other hand, in case of using the regular-size recording paper
cassette, the ordinary print processing is performed. Then, the
flow returns to the step S400 to wait for a next print command.
[0173] On the other hand, if the recording paper size has not been
determined, the flow advances to a step S403 to change the
controlling state. That is, the controlling is performed to start
misprint processing. In the misprint processing, it is set not to
perform the paper feeding. Also, in this processing, a misprint
state to wait for misprint releasing is set, and also it notifies a
user of the misprint state through the host computer 136 or the
operation panel 127.
[0174] Subsequently, the flow advances to a step S404 to wait for
the misprint releasing. The misprint releasing is performed by
opening/closing of a door, a releasing instruction from the host
computer 136, a releasing instruction from the operation panel 127
or the like. If the misprint releasing by any method is received,
the misprint state is released, and the flow again returns to the
step S400 to wait for a next print command.
[0175] As above, if the recording paper size has not been
determined, the controlling is performed such that the paper
feeding is not performed but the misprint processing is performed.
Therefore, in the case where it is necessary to designate the
recording paper size as in the case of using the free-size cassette
104, it can be prevented that an error occurs because the user
forgets to designate the recording paper size. Also, the user can
recognize such the forgetting.
[0176] (Seventh Embodiment)
[0177] Subsequently, the seventh embodiment of the present
invention will be explained with reference to FIG. 24. FIG. 24 is
the flow chart showing a series of processing procedure from print
command receiving to print processing in the seventh embodiment of
the image forming apparatus according to the present invention.
[0178] The present embodiment has the same structure as that in the
first embodiment. It should be noted that, as a matter of
convenience, the same components as those in FIG. 1 are added with
the same reference numerals. The present embodiment is different
from the sixth embodiment in the point that, when it is judged that
a size of a recording paper to be fed has not been determined,
controlling is performed not to accept a print command.
[0179] Concretely, as shown in FIG. 24, it waits for the print
command in a step S500. When the print command is received, the
flow advances to a step S501 to judge whether or not the recording
paper size has been determined in the same manner as in the above
step S401. If the recording paper size has been determined, the
flow advances to a step S502 to perform the controlling such that
the print processing starts. This print processing is the same as
that in the above step S402.
[0180] On the other hand, if the recording paper size has not been
determined, the print command at this time is ignored, and the flow
returns to the step S500 again to wait for a next print
command.
[0181] As above, in the case where the recording paper size has not
been determined, it is controlled not to accept the print command.
Therefore, in a case where it is necessary to designate the
recording paper size as in case of using a free-size cassette 104,
even if a user forgets to designate the size, he can easily confirm
such a fact. Also, there is no need for the user to perform
misprint releasing.
[0182] (Eighth Embodiment)
[0183] Subsequently, the eighth embodiment of the present invention
will be explained with reference to FIG. 25. FIG. 25 is the flow
chart showing a series of processing procedure from print command
receiving to print processing in the eighth embodiment of the image
forming apparatus according to the present invention.
[0184] The present embodiment has the same structure as that in the
first embodiment. It should be noted that, as a matter of
convenience, the same components as those in FIG. 1 are added with
the same reference numerals. The present embodiment is different
from the seventh embodiment in the point that, when it is judged
that a size of a recording paper to be fed has not been determined,
controlling is performed not to accept a print command and to
notify a user of such a fact.
[0185] Concretely, as shown in FIG. 25, it waits for the print
command in a step S600. When the print command is received, the
flow advances to a step S601 to judge whether or not the recording
paper size has been determined in the same manner as in the above
step S401. If the recording paper size has been determined, the
flow advances to a step S602 to perform the controlling such that
the print processing starts. This print processing is the same as
that in the above step S402. Then, the flow returns to the step
S600 again to wait for a next print command.
[0186] On the other hand, if the recording paper size has not been
determined, the flow advances to a step S603 to ignore the print
command at this time and also notify the user of such the fact
through a host computer 136 or an operation panel 127. Then, the
flow returns to the step S600 again to wait for the next print
command.
[0187] As above, in the case where the recording paper size has not
been determined, it is controlled not to accept the print command
and to notify the user of such the fact, whereby usability can be
further improved.
[0188] (Ninth Embodiment)
[0189] Subsequently, the ninth embodiment of the present invention
will be explained with reference to FIG. 26. FIG. 26 is the
structural view showing a free-size cassette used in the ninth
embodiment of the image forming apparatus according to the present
invention.
[0190] A free-size cassette 104 used in the present embodiment is
the cassette which can be also mounted to the apparatus in the
above first embodiment. As shown in FIG. 26, the free-size cassette
104 has a recording paper trailing edge stopping board 501 which
also acts as a cassette case and into which a trailing edge of a
recording paper 105 runs. When the trailing edge of the paper 105
runs into the board 501, the paper 105 is put on a bottom board 129
of the cassette 104 from its trailing edge. The bottom board 129 is
structured such that it can be moved up and down according to the
number of recording papers 105 put thereon.
[0191] In the cassette case, a recording paper leading edge
partition board 502 which runs into a leading edge of the recording
paper 105 is provided movably in a paper conveying direction
according to a size of the paper 105. A conveying sheet 503 to
constitute a conveying path of the paper 105 is arranged between
the partition board 502 and a leading edge of the cassette case.
One end of the conveying sheet 503 is fixed to the partition board
502 and the other end thereof is fixed to a sheet holding roller
504 provided at the leading edge of the cassette case. The
conveying sheet 503 is wound around the sheet holding roller 504 to
adjust a length of the sheet 503 between the board 502 and the
leading edge of the case which length changes according to the
moving of the partition board 502.
[0192] Like the first embodiment, the recording paper 105 put in
the free-size cassette 104 having the above structure is conveyed
by driving a pickup roller 108. Presence/absence of the paper 105
is detected by a paper sensor 107 consisting of a sensor flag 107a
and a photointerrupter 107b. In addition to the paper sensor 107, a
recording paper sensor 508 is further provided at a position
adjacent to the leading edge of the cassette case. The recording
paper sensor 508 includes a sensor to detect the leading edge of
the paper 105 conveyed by driving the pickup roller 108, and such
the sensor further consists of a sensor flag 506 and a
photointerrupter 507.
[0193] In the above structure, it is assumed that a time from
driving start of the pickup roller 108 to detecting of the leading
edge of the paper 105 by the sensor 508 is represented by Ts,
recording paper conveying speed by the pickup roller 108 is
represented by Vs (mm/sec) and a distance from the stopping board
501 to the sensor 508 in the conveying direction is represented by
Ls (mm). If so, a dimension l (mm) in the conveying direction of
the recording paper 105 can be obtained by a following equation
(3).
l=Ls-Vs.times.Ts (3)
[0194] As above, by structuring the free-size cassette 104 and also
newly providing the recording paper sensor 508, the dimension l in
the conveying direction of the recording paper 105 can be
calculated without providing any complicated detecting mechanism.
Therefore, it becomes unnecessary to designate the dimension in the
conveying direction of the paper 105 when the recording size is
designated.
[0195] (Tenth Embodiment)
[0196] Subsequently, the tenth embodiment of the present invention
will be explained with reference to FIG. 27. FIG. 27 is the
structural view showing a free-size cassette used in the tenth
embodiment of the image forming apparatus according to the present
invention.
[0197] The present embodiment is different from the ninth
embodiment in the point that a pickup roller 108 is driven by a
stepping motor 505. That is, in the present embodiment, a dimension
l (mm) in a conveying direction of a recording paper 105 is
calculated by using the number of driving pulses of the stepping
motor 505.
[0198] Concretely, it is assumed that the number of driving pulses
of the motor 505 obtained for a time from driving start of the
pickup roller 108 to detecting of a leading edge of the paper 105
by a recording paper sensor 508 is represented by Ps, a recording
paper conveying distance by the pickup roller 108 for the number of
pulses of one driving of the stepping motor 505 is represented by
Lp (mm), and a conveying-direction distance from a recording paper
trailing edge stopping board 501 to the recording paper sensor 508
is represented by Ls (mm). If so, a dimension l (mm) in the
conveying direction of the recording paper 105 can be obtained by a
following equation (4).
l=Ls-Lp.times.Ps (4)
[0199] As above, the dimension l in the conveying direction of the
paper 105 can be calculated by using the number of driving pulses
of the stepping motor 505.
* * * * *