U.S. patent application number 15/868237 was filed with the patent office on 2018-08-16 for document conveyance apparatus and image forming apparatus.
This patent application is currently assigned to KONICA MINOLTA, INC.. The applicant listed for this patent is KONICA MINOLTA, INC.. Invention is credited to Kouei CHO, Akinori KIMATA, Kiyohito TSUJIHARA, Shiro UMEDA, Takashi WATANABE, Kazutoshi YOSHIMURA.
Application Number | 20180229956 15/868237 |
Document ID | / |
Family ID | 63106134 |
Filed Date | 2018-08-16 |
United States Patent
Application |
20180229956 |
Kind Code |
A1 |
YOSHIMURA; Kazutoshi ; et
al. |
August 16, 2018 |
DOCUMENT CONVEYANCE APPARATUS AND IMAGE FORMING APPARATUS
Abstract
Provided is a document conveyance apparatus that conveys a
document along a document conveyance path including a reading
position at which an image on a surface of the document is read,
the document conveyance apparatus including: a hardware processor;
an end detector that detects an angle of a corner portion of a
front edge of the document; and an inclination detector that
detects an amount of inclination of the front edge, wherein, in a
case where it has been determined that the corner portion of the
front edge includes a right angle portion on the basis of
information obtained from the end detector, the hardware processor
determines the amount of inclination of the front edge obtained
from the inclination detector as an amount of inclination of the
document, and performs inclination correction of the image read at
the reading position.
Inventors: |
YOSHIMURA; Kazutoshi;
(Toyokawa-shi, JP) ; TSUJIHARA; Kiyohito;
(Toyokawa-shi, JP) ; KIMATA; Akinori;
(Toyokawa-shi, JP) ; WATANABE; Takashi;
(Toyokawa-shi, JP) ; UMEDA; Shiro; (Toyokawa-shi,
JP) ; CHO; Kouei; (Toyohashi-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KONICA MINOLTA, INC. |
Tokyo |
|
JP |
|
|
Assignee: |
KONICA MINOLTA, INC.
Tokyo
JP
|
Family ID: |
63106134 |
Appl. No.: |
15/868237 |
Filed: |
January 11, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65H 2801/39 20130101;
B65H 2511/414 20130101; B65H 9/004 20130101; B65H 5/062 20130101;
H04N 1/0057 20130101; B65H 2801/06 20130101; H04N 1/00718 20130101;
B65H 7/02 20130101; B65H 3/06 20130101; H04N 2201/0094 20130101;
H04N 1/00588 20130101; H04N 1/3878 20130101; B65H 2511/20 20130101;
B65H 2553/822 20130101; B65H 2701/111 20130101; H04N 1/00782
20130101; B65H 29/125 20130101; H04N 1/0066 20130101; H04N 1/00734
20130101; H04N 1/00615 20130101; H04N 1/00602 20130101; B65H
2701/131 20130101; B65H 7/14 20130101; H04N 1/00639 20130101; B65H
7/20 20130101; H04N 1/00745 20130101; B65H 2511/414 20130101; B65H
2220/02 20130101; B65H 2511/20 20130101; B65H 2220/03 20130101;
B65H 2701/131 20130101; B65H 2220/01 20130101; B65H 2701/111
20130101; B65H 2220/03 20130101 |
International
Class: |
B65H 9/00 20060101
B65H009/00; B65H 3/06 20060101 B65H003/06; B65H 5/06 20060101
B65H005/06; B65H 7/14 20060101 B65H007/14; B65H 29/12 20060101
B65H029/12 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 15, 2017 |
JP |
2017-026077 |
Claims
1. A document conveyance apparatus that conveys a document along a
document conveyance path, the document conveyance path including a
reading position at which an image on a surface of the document is
read, the document conveyance apparatus comprising: a hardware
processor; an end detector that is disposed in the document
conveyance path and detects an angle of a corner portion of a front
edge of the document, the front edge being on a front side in a
conveyance direction of the document as viewed in the conveyance
direction; and an inclination detector that detects an amount of
inclination of the front edge with respect to the conveyance
direction, wherein, in a case where it has been determined that the
corner portion of the front edge includes a right angle portion on
the basis of information obtained from the end detector, the
hardware processor determines the amount of inclination of the
front edge obtained from the inclination detector as an amount of
inclination of the document, and performs, with reference to the
front edge, inclination correction of the image read at the reading
position.
2. The document conveyance apparatus according to claim 1, wherein
in a case where it has been determined that the corner portion of
the front edge does not include a right angle portion on the basis
of the information obtained from the end detector, the hardware
processor performs control such that the end detector detects an
angle of a corner portion of a rear edge of the document, the rear
edge being on a rear side in the conveyance direction as viewed in
the conveyance direction, and that the inclination detector detects
an amount of inclination of the rear edge with respect to the rear
edge, and in a case where it has been determined that the corner
portion of the rear edge includes a right angle portion on the
basis of information obtained from the end detector, the hardware
processor determines the amount of inclination of the rear edge
obtained from the inclination detector as the amount of inclination
of the document, and performs, with reference to the rear edge,
inclination correction of the image read at the reading
position.
3. The document conveyance apparatus according to claim 2, wherein,
in a case where it has been determined that neither of the corner
portion of the front edge of the document nor the corner portion of
the rear edge of the document includes a right angle portion on the
basis of the information obtained from the end detector, the
hardware processor stops conveyance of the document.
4. The document conveyance apparatus according to claim 1, wherein,
in a case of reading both of an image on a front surface of the
document and an image on a back surface of the document, the
hardware processor performs the same inclination correction on the
image on the back surface as on the image on the front surface.
5. An image forming apparatus comprising: a document conveyance
apparatus that conveys a document along a document conveyance path,
the document conveyance path including a reading position at which
an image on a surface of the document is read; and an image former
that forms an image on the basis of the image read by the document
conveyance apparatus, wherein the document conveyance apparatus
includes: a hardware processor; an end detector that is disposed in
the document conveyance path and detects an angle of a corner
portion of a front edge of the document, the front edge being on a
front side in a conveyance direction of the document as viewed in
the conveyance direction; and an inclination detector that detects
an amount of inclination of the front edge with respect to the
conveyance direction, and in a case where it has been determined
that the corner portion of the front edge includes a right angle
portion on the basis of information obtained from the end detector,
the hardware processor determines the amount of inclination of the
front edge obtained from the inclination detector as an amount of
inclination of the document, and performs, with reference to the
front edge, inclination correction of the image read at the reading
position.
6. The image forming apparatus according to claim 5, wherein in a
case where it has been determined that the corner portion of the
front edge does not include a right angle portion on the basis of
the information obtained from the end detector, the hardware
processor performs control such that the end detector detects an
angle of a corner portion of a rear edge of the document, the rear
edge being on a rear side in the conveyance direction as viewed in
the conveyance direction, and that the inclination detector detects
an amount of inclination of the rear edge with respect to the rear
edge, and in a case where it has been determined that the corner
portion of the rear edge includes a right angle portion on the
basis of information obtained from the end detector, the hardware
processor determines the amount of inclination of the rear edge
obtained from the inclination detector as the amount of inclination
of the document, and performs, with reference to the rear edge,
inclination correction of the image read at the reading
position.
7. The image forming apparatus according to claim 6, wherein, in a
case where it has been determined that neither of the corner
portion of the front edge of the document nor the corner portion of
the rear edge of the document includes a right angle portion on the
basis of the information obtained from the end detector, the
hardware processor stops conveyance of the document.
8. The image forming apparatus according to claim 5, wherein, in a
case of reading both of an image on a front surface of the document
and an image on a back surface of the document, the hardware
processor performs the same inclination correction on the image on
the back surface as on the image on the front surface.
Description
[0001] The entire disclosure of Japanese patent Application No.
2017-026077, filed on Feb. 15, 2017, is incorporated herein by
reference in its entirety.
BACKGROUND
Technological Field
[0002] The present invention relates to an image forming apparatus
for forming an image by an electrophotographic method and a
document conveyance apparatus used for the same. The image forming
apparatus includes a recording apparatus, a display apparatus, and
an electrophotography apparatus such as a digital copier, a
facsimile machine, and a printer, regardless of color or
monochrome.
Description of the Related Art
[0003] JP 2012-085232 A, JP 2016-036065 A, and JP 2015-170927 A
each disclose an invention relating to an image processing
apparatus.
[0004] The image processing apparatus disclosed in JP 2012-085232 A
adopts a technique of determining the orientation of a partial
image of character attribute and, in the case where the orientation
is not correct, rotating the partial image of character attribute
so that the orientation becomes correct.
[0005] In JP 2016-036065 A, a reading apparatus extracts edges of a
document from image data, and obtains inclination .alpha. of a
leading edge Et of the document and inclination .beta. of a
trailing edge Eb of the document on the basis of the extracted
edge, and, in the case where the difference between the inclination
.alpha. and the inclination .beta. is larger than a rotational skew
threshold value, a scanner determines that rotational skew in which
the inclination of the document changes in accordance with
conveyance of the document has occurred. Thereafter, a technique in
which the inclination of the leading edge and the inclination of
the trailing edge are compared, and at least one of determining a
takeout range and determining the amount of rotation is executed on
the basis of the inclination with a smaller inclination angle is
adopted.
[0006] The image reading apparatus disclosed in JP 2015-170927 A
includes a document type and/or document discriminator, and selects
an appropriate document inclination detection method in accordance
with the discriminated document type and/or document. JP
2015-170927 A discloses a technique in which a document region is
detected by selecting a reliable end which is a predetermined
document end as a target for detection of the position of the
document and detecting the inclination of the document and/or the
position of the document with reference to the selected reliable
end.
[0007] In the related art, the inclination of a read image is
corrected with reference to an edge portion of the leading end of
the document. However, in the case where a user defines an edge on
the cut section side of a document cut by the user as the front end
of the document, if the cut section is oblique (if the leading end
and the trailing end of the document are not parallel), inclination
correction is performed with reference to the oblique cut section,
and the read image is inclined (an example of a cut document).
[0008] As disclosed in JP 2012-085232 A, there is also a method of
correcting the inclination with reference to characters in the
image by using an optical character recognition (OCR) function.
However, there is no guarantee that the characters and the
inclination of the document match.
[0009] In the technique disclosed in JP 2016-036065 A, inclination
of an edge including an angle and a direction. corresponding to a
direction orthogonal to a document conveyance direction is
detected. A case of a regular size sheet is assumed, and, for
example, in the case of using a book as a document, the binding
direction is different depending on whether the characters are
arranged vertically or horizontally, and at which of the leading
end and the trailing end a cut section is set in the conveyance
direction is unknown. Furthermore, in the case where one of the
leading end or the trailing end is a cut end and the inclination of
the read image on the cut end side is small, the inclination is
corrected with reference to the cut end.
[0010] In the technique disclosed in JP 2015-170927 A, a document
type and a document shape are detected from a scanned image, and an
inclination correction method is selected on the basis of a
detection result. However, since the process is started after all
images have been read once, the process takes time, and thus is
unsuitable for high-speed reading of a large number of
documents.
SUMMARY
[0011] An object of the present invention set on the basis of the
problems above is to provide a document conveyance apparatus and an
image forming apparatus which enable determining whether a document
set on a tray by a user is inclined due to conveyance or an end
portion (cut section) of a document is oblique, and on the basis of
the result of determination, performing appropriate inclination
correction in high-speed reading of a large number of documents
irrespective of the direction in which the user has set the
documents.
[0012] To achieve the abovementioned object, according to an aspect
of the present invention, there is provided a document conveyance
apparatus that conveys a document along a document conveyance path,
the document conveyance path including a reading position at which
an image on a surface of the document is read, and the document
conveyance apparatus reflecting one aspect of the present invention
comprises: a hardware processor; an end detector that is disposed
in the document conveyance path and detects an angle of a corner
portion of a front edge of the document, the front edge being on a
front side in a conveyance direction of the document as viewed in
the conveyance direction; and an inclination detector that detects
an amount of inclination of the front edge with respect to the
conveyance direction, wherein, in a case where it has been
determined that the corner portion of the front edge includes a
right angle portion on the basis of information obtained from the
end detector, the hardware processor determines the amount of
inclination of the front edge obtained from the inclination
detector as an amount of inclination of the document, and performs,
with reference to the front edge, inclination correction of the
image read at the reading position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The advantages and features provided by one or more
embodiments of the invention will become more fully understood from
the detailed description given hereinbelow and the appended
drawings which are given by way of illustration only, and thus are
not intended as a definition of the limits of the present
invention:
[0014] FIG. 1 is a perspective view showing a configuration of an
image forming apparatus according to an embodiment;
[0015] FIG. 2 is a block diagram showing a configuration of the
image forming apparatus according to the embodiment;
[0016] FIG. 3 is a diagram showing an internal configuration of a
scanner unit and an automatic document feeder (ADF) unit according
to the embodiment;
[0017] FIG. 4 is a diagram showing a left binding document;
[0018] FIG. 5 is a diagram showing a right binding document;
[0019] FIG. 6 is a diagram showing a document bound by using
staples;
[0020] FIG. 7 is a diagram showing a case where a cut section
(cutting line) of the document is oblique;
[0021] FIG. 8 is a schematic diagram showing arrangement positions
of sensors with respect to a conveyance center line of a conveyed
document;
[0022] FIG. 9 is a diagram showing an arrangement relationship
between a conveyed document and each sensor position;
[0023] FIG. 10 is a schematic diagram showing a detection method of
a conveyance state of a conveyed document, and is a diagram showing
a case where a cut section of the document is orthogonal;
[0024] FIG. 11 is a diagram schematically showing detection timings
of inclination sensors and an end detection sensor in the case of
the document shown in FIG. 10;
[0025] FIG. 12 is a schematic diagram showing a detection method of
a conveyance state of a conveyed document, and is a diagram showing
a case where a cut section of the document on the rear side is
inclined;
[0026] FIG. 13 is a diagram schematically showing detection timings
of the inclination sensors and the end detection sensor in the case
of the document shown in FIG. 12;
[0027] FIG. 14 is a schematic diagram showing a detection method of
a conveyance state of a conveyed document, and is a diagram showing
a case where a cut section of the document on the front side is
inclined;
[0028] FIG. 15 is a diagram schematically showing detection timings
of the inclination sensors and the end detection sensor in the case
of the document shown in FIG. 14;
[0029] FIG. 16 is a diagram schematically showing an inclination
correction flow for an image using the inclination sensors and the
end detection sensor shown in FIGS. 12 to 15;
[0030] FIG. 17 is a schematic diagram showing a detection method of
a conveyance state of a conveyed document, and is a diagram showing
a case where the conveyed document is inclined and the cut section
of the document is orthogonal;
[0031] FIG. 18 is a diagram schematically showing detection timings
of the inclination sensors and the end detection sensor in the case
of the document shown in FIG. 17;
[0032] FIG. 19 is a schematic diagram showing a detection method of
a conveyance state of a conveyed document, and is a diagram showing
a case where the conveyed document is inclined and the cut section
of the document on the rear side is inclined;
[0033] FIG. 20 is a diagram schematically showing detection timings
of the inclination sensors and the end detection sensor in the case
of the document shown in FIG. 19;
[0034] FIG. 21 is a schematic diagram showing a detection method of
a conveyance state of a conveyed document, and is a diagram showing
a case where the conveyed document is inclined and the cut section
of the document on the front side is inclined;
[0035] FIG. 22 is a diagram schematically showing detection timings
of the inclination sensors and the end detection sensor in the case
of the document shown in FIG. 21;
[0036] FIG. 23 is a diagram showing another position of the end
detection sensor;
[0037] FIG. 24 is a diagram showing yet another position of the end
detection sensor;
[0038] FIG. 25 is a schematic diagram showing a detection method of
a conveyance state of a conveyed document, and is a diagram showing
a case where a cut section of the document of an upper end is
inclined; and
[0039] FIG. 26 is a diagram schematically showing detection timings
of the inclination sensors and the end detection sensor in the case
of the document shown in FIG. 25.
DETAILED DESCRIPTION OF EMBODIMENTS
[0040] Hereinafter, an image forming apparatus according to one or
more embodiments of the present invention will be described with
reference to the drawings. However, the scope of the invention is
not limited to the disclosed embodiments. In the embodiment
described below, when referring to the number, amount, etc., the
scope of the present invention is not necessarily limited to the
number, amount, etc. unless otherwise stated. Identical parts and
equivalent parts are denoted by the same reference numerals, and
redundant explanations may not be repeated. In the drawings,
illustration is not given in accordance with the ratio of the
actual dimensions, and is given at some parts by changing the ratio
for the sake of easier understanding of the structure.
[0041] Examples of the image forming apparatus include a
multi-function printer (MFP), a facsimile machine, or a copier. The
MFP has a scanner function, a copying function, a function as a
printer, a facsimile function, a data communication function, and a
server function. In addition, a document conveyance apparatus is an
automatic document feeder (ADF) unit provided in the image forming
apparatus.
[0042] [Configuration of Image Forming Apparatus 1]
[0043] Referring to FIG. 1 to FIG. 3, an image forming apparatus 1
of the present embodiment will be described. FIG. 1 is a
perspective view showing a configuration of the image forming
apparatus 1, FIG. 2 is a block diagram showing a configuration of
the image forming apparatus 1, and FIG. 3 is a diagram showing an
internal configuration of a scanner unit and the ADF unit.
[0044] Referring to FIG. 1, the image forming apparatus 1 is an
MFP. The image forming apparatus 1 includes a controller 10, an
image former 20, a sheet feeder 30, a scanner unit 40, an ADF (Auto
Document Feeder) unit 50 serving as a document conveyance
apparatus, and an operation panel 60. The controller 10, the image
former 20, and the sheet feeder 30 are located in the center of the
image forming apparatus 1. The scanner unit 40 and the ADF unit 50
are located in an upper portion the image forming apparatus 1. The
operation panel 60 is located on a front upper surface of the image
forming apparatus 1.
[0045] Referring to FIG. 2, the controller 10 includes a central
processing unit (CPU) 11, a read only memory (ROM) 12, a random
access memory (RAM) 13, a communication interface (I/F) 14, an
image data storage 15, and a document size storage 16. The CPU 11,
the ROM 12, the RAM 13, the communication I/F 14, the image data
storage 15, and the document size storage 16 are connected to one
another.
[0046] The CPU 11 controls the overall operation of the image
forming apparatus 1. The ROM 12 stores a control program executed
by the CPU 11. The RAM 13 is a work memory for the CPU 11. The
communication I/F 14 transmits and receives various kinds of
information to and from external devices (not shown) through a
network or the like. The image data storage 15 stores image data
read by the scanner unit 40 and the like. The document size storage
16 stores the size of a document measured by the ADF unit 50 and
the size of a document set through the operation panel 60.
[0047] Roughly speaking, the image former 20 is constituted by a
toner image former and a fixing device. The image former 20 forms
an image on a sheet by, for example, an electrophotographic method.
The image former 20 is configured to be able to form a color image
on a sheet by combining images of four colors in a so-called tandem
system.
[0048] The toner image former includes photosensitive members
provided for respective colors of cyan (C), magenta M, yellow Y,
and black K, an intermediate transfer belt to which toner images
are transferred from the photosensitive members, and a transfer
unit that transfers (secondary transfer) an image from the
intermediate transfer belt to a sheet.
[0049] The fixing device includes a heating roller and a
pressurizing roller. The fixing device conveys a sheet on which a
toner image has been formed by the heating roller and the
pressurizing roller while nipping the sheet therebetween, and heats
and pressurizes the sheet. As a result, the fixing device melts the
toner adhered to the sheet, fixes the toner on the sheet, and thus
forms an image on the sheet.
[0050] The sheet feeder 30 is constituted by a sheet feeding
roller, a conveyance roller, a motor for driving these, and the
like. The sheet feeder 30 feeds a sheet from a sheet feeding
cassette and conveys the sheet inside the housing of the image
forming apparatus 1. The sheet feeder 30 discharges the sheet on
which the image has been formed from the image forming apparatus 1
to a sheet discharge tray or the like. The scanner unit 40 reads an
image of a document and generates image data of the document.
[0051] The ADF unit 50 sends documents (an example of sheets) one
by one to the scanner unit 40. The ADF unit 50 includes a document
conveyance motor 51, a back surface reader 52 provided in the case
of double-sided simultaneous reading at the time of document
conveyance, a document size detection sensor 53, a pre-document
reading sensor 54, an inclination sensor (R) 55, an inclination
sensor (F) 56, and an end detection sensor 57. The document
conveyance motor 51 operates under the control of the CPU 11.
[0052] The document conveyance motor 51 includes an upstream roller
driving motor and a downstream roller driving motor. The upstream
roller driving motor drives a sheet feeding roller 154 (FIG. 3).
The downstream roller driving motor drives conveyance rollers 155,
156, 157, 158 and a sheet discharge roller 159 (FIG. 3). The
document size detection sensor 53 detects the size of the document
placed on a document tray 151 (FIG. 3). The pre-document reading
sensor 54 detects the presence or absence of the document along a
conveyance path, and is constituted by an optical or mechanical
sensor.
[0053] The detailed arrangement of the inclination sensor (R) 55,
the inclination sensor (F) 56, and the end detection sensor 57 will
be described later. Optical or mechanical sensors are used for the
inclination sensor (R) 55, the inclination sensor (F) 56, and the
end detection sensor 57, similarly to the pre-document reading
sensor 54.
[0054] More specifically, the inclination sensor (R) 55 and the
inclination sensor (F) 56 detect passage of an end portion of the
sheet. Specifically, for example, one photoelectric sensor is used
to detect the passage of the end portion of the sheet by blocking a
light beam. The end detection sensor 57 detects the shape of a
corner portion of the sheet. Specifically, a photoelectric sensor
arranged in a matrix is used to determine whether or not the corner
portion of the sheet includes a right angle depending on a light
blocking state.
[0055] The operation panel 60 displays various information and
accepts various operations. The operation panel 60 includes a start
button 61 for starting various jobs such as a reading job and a
copying job.
[0056] Referring to FIG. 3, the ADF unit 50 is positioned above the
scanner unit 40. The scanner unit 40 is capable of reading a
document placed on a document table 141 and reading a document sent
from the ADF unit 50.
[0057] The scanner unit 40 includes the document table 141, a light
source 142, mirrors 143a, 143b, and 143c, and a charge coupled
device (CCD) 144. Light emitted from the light source 142 and
reflected by the surface of a document is reflected by each of the
mirrors 143a, 143b, and 143c, and is incident on the CCD 144. Thus,
the scanner unit 40 reads the document.
[0058] The ADF unit 50 includes the document tray 151, a sheet
discharge tray 152, a pickup roller 153, the sheet feeding roller
154, the conveyance rollers 155, 156, 157, and 158, the sheet
discharge roller 159, and a contact image sensor (CIS) 160. A
document to be read is placed or the document tray 151. A document
size detection sensor 53 for mechanically detecting the document is
provided on the upper surface of the document tray 151, and the
size of the placed document is measured on the basis of a detection
result of the document size detection sensor 53. The document whose
image has been read is discharged from the ADF unit 50 onto the
sheet discharge tray 152.
[0059] A conveyance path TR connecting the document tray 151 to the
sheet discharge tray 152 is provided in the ADF unit 50. The pickup
roller 153, the sheet feeding roller 154, the conveyance rollers
155, 156, 157, and 158, and the sheet discharge roller 159 are
arranged in this order from the document tray 151 to the sheet
discharge tray 152 along the conveyance path TR. A reading position
RP is provided between the conveyance roller 156 and the conveyance
roller 157. The CIS 160 is provided between the conveyance roller
157 and the conveyance roller 158.
[0060] The ADF unit 50 sequentially supplies documents placed on
the document tray 151 one by one to the conveyance path TR by the
pickup roller 153 and the sheet feeding roller 154. The ADF unit 50
performs registration correction on a document supplied to the
conveyance path TR by using the conveyance roller 155. The ADF unit
50 conveys the document supplied to the conveyance path TR along
the conveyance path TR to the reading position RP by the conveyance
rollers 155 and 156.
[0061] The scanner unit 40 reads a front surface of the conveyed
document at the reading position RP. Next, the ADF unit 50 conveys
the document whose front surface has been read to the CIS 160 along
the conveyance path TR by the conveyance roller 157. The scanner
unit 40 reads a back surface of the conveyed document by the CIS
160. Thereafter, the ADF unit 50 conveys the document along the
conveyance path TR to a discharge port by the conveyance roller
158, and discharges the document onto the sheet discharge tray 152
by the sheet discharge roller 159.
[0062] (Inclination Detection of Document)
[0063] The inclination sensor (R) 55, the inclination sensor (F)
56, and the end detection sensor 57 are arranged in the conveyance
path TR. Hereinafter, a method for determining whether the document
set on the document tray by the user is inclined due to conveyance
or an end portion of the document (cut section) is oblique using
this arrangement and these sensors will be described below with
reference to drawings.
[0064] Referring to FIG. 4 to FIG. 7, cutting modes of the document
will be described. FIG. 4 shows a document B1 bound on the left,
FIG. 5 shows a document B2 bound on the right, FIG. 6 shows a
document bound by using staples, and FIG. 7 shows a case Where the
cut section (cutting line) of the document is oblique.
[0065] Normally, in the case of the document B1 bound on the left
shown in FIG. 4, the document is opened from the right side to the
left side. Characters are arranged horizontally. In the case of the
document 132 bound on the right shown in FIG. 5, the document is
opened from the left side to the right side. Characters are
arranged vertically. As shown in FIG. 6, in the document using
staples ST, cutting is performed such that portions corresponding
to the staples ST are cut off. Referring to FIG. 7, the case where
the cut section (cutting line) S1 of a document P11 is oblique will
be shown.
[0066] Referring to FIG. 8 and FIG. 9, description will be given
for each sensor position provided in the conveyance path TR. FIG. 8
is a schematic diagram showing the positions of the sensors with
respect to a conveyance center line CL of the conveyed document,
and FIG. 9 is a diagram showing the arrangement relationship
between the conveyed document and each sensor position.
[0067] Referring to FIG. 8, an arrow in FIG. 8 corresponds a
document conveyance direction F1. In the case of the image forming
apparatus 1 shown in FIG. 1, the left side in FIG. 8 is the rear
side of the apparatus and the right side in FIG. 8 is the front
side of the apparatus when viewed in the document conveyance
direction F1 in the ADF unit 50.
[0068] As shown in FIG. 8, a pre-document reading sensor 54 is
disposed at a position displaced by an amount S1 toward the front
side of the apparatus with respect to the conveyance center line
CL. With respect to the conveyance center line CL, the inclination
sensor (R) 55 is disposed at a position displaced by an amount S2
toward the rear side of the apparatus, and the inclination sensor
(F) 56 is disposed at a position displaced by an amount S3 toward
the front side of the apparatus.
[0069] In the present embodiment, as an example, the pre-document
reading sensor 54 is disposed at a position of 6.0 mm as the amount
S1, the inclination sensor (R) 55 and the inclination sensor (F) 56
are disposed at positions of 87.0 mm as the amounts S2 and S3.
Further, as shown in FIG. 9, the end detection sensor 57 is
disposed in the vicinity of the inclination sensor (F) 56 disposed
on the front side of the device.
[0070] As shown in FIG. 3, regarding the positions of the
inclination sensor (R) 55, the inclination sensor (F) 56, and the
end detection sensor 57 in the ADF unit 50, the inclination sensor
(R) 55 and the inclination sensor (F) 56 are arranged on
substantially the same line as the pre-document reading sensor 54
in a direction orthogonal to the document conveyance direction F1.
When viewed along the conveyance direction F1 of the document, the
end detection sensor 57 is disposed downstream of the inclination
sensor (R) 55 and the inclination sensor (F) 56 and upstream of the
reading position RP.
[0071] As described above, the inclination sensor (R) 55 and the
inclination sensor (F) 56 detect passage of an end portion of the
sheet. The end detection sensor 57 detects the shape of a corner
portion of the sheet.
[0072] Referring to FIGS. 10 to 16, a method for detecting the
conveyance state of the conveyed document will be described. FIG.
10 shows a case of a document P10 with an orthogonal cut section,
and FIG. 11 is a diagram schematically showing detection timings of
the inclination sensor (R) 55, the inclination sensor (F) 56, and
the end detection sensor 57 in the case of the document P10 shown
in FIG. 10. The document P10 may be bound on the right side or
bound on the left side.
[0073] FIG. 12 shows a case of a document P11 whose cut section on
the rear side is inclined, and FIG. 13 is a diagram schematically
showing detection timings of the inclination sensor (R) 55, the
inclination sensor (F) 56, and the end detection sensor 57 in the
case of the document P11 shown in FIG. 11. The document P11 is
usually bound on the right side.
[0074] FIG. 14 shows a case of a document P12 whose cut section on
the front side is inclined, and FIG. 15 is a. diagram schematically
showing detection timings of the inclination sensor (R) 55, the
inclination sensor (F) 56, and the end detection sensor 57 in the
case of the document P12 shown in FIG. 14. The document P12 is
usually bound on the left side.
[0075] FIG. 16 is a diagram schematically showing an inclination
correction flow for an image using the inclination sensor (R) 55,
the inclination sensor (F) 56, and the end detection sensor 57
shown in FIGS. 12 to 15.
[0076] Referring to FIGS. 10, 11 and 16, the document P10 is
conveyed (S10), and it is detected by the end detection sensor 57
that a front corner portion C1 of the document P11 includes a right
angle (S20 and S30). Next, as a front end P10f and a rear end P10r
of the document P10 sequentially pass by the inclination sensor (R)
55 and the inclination sensor (F) 56, widths W11 and W12 of the
document P10 along the conveyance direction being the same is
detected. As a result, it is detected that a cut section S1 of the
document P10 is orthogonal, and the amount of inclination of the
front end P10f is detected (S40). Next, inclination correction is
performed on a read image with reference to the front side of the
document P10 (S50). Specifically, in the case of this document.
P10, the inclination correction of the image is zero.
[0077] Referring to FIGS. 12, 13 and 16, the document P11 is
conveyed (S10), and it is detected by the end detection sensor 57
that a front corner portion C1 of the document P11 includes a right
angle (S20 and S30). Next, as a front end P11f and a rear end P11r
of the document P11 sequentially pass by the inclination sensor (R)
55 and the inclination sensor (F) 56, widths W11 and W12 of the
document P11 along the conveyance direction being different is
detected.
[0078] However, the front end P11f of the document P11 passes by
the inclination sensor (R) 55 and the inclination sensor (F) 56 at
the same time. As a result, it is detected that the front end P11f
of the document P11 is orthogonal, and the amount of inclination of
the front end P11f is detected (S40). Next, the inclination
correction of the read image is performed with reference to the
front side of the document P11 (S50). Specifically, in the case
adds document P11, the inclination correction of the image is
zero.
[0079] Referring to FIGS. 14, 15 and 16, the document P12 is
conveyed (S10), and it is detected by the end detection sensor 57
that a front corner portion C1 of the document P12 does not include
a right angle (S20 and S30). Next, as a front end P12f and a rear
end P12r of the document P12 sequentially pass by the inclination
sensor (R) 55 and the inclination sensor (F) 56, widths W11 and W12
of the document P12 along the conveyance direction being different
is detected.
[0080] However, the rear end P12r of the document P12 passes though
the inclination sensor (R) 55 and the inclination sensor (F) 56 at
the same time. Further, the end detection sensor 57 detects that a
corner portion C2 on the rear side of the document P12 includes a
right angle (S60). As a result, it is determined that the rear end
P12r is orthogonal although the front end P12f of the document P12
is not orthogonal (S70). Next, inclination correction of the read
image is performed with reference to the rear side of the document
P12 (S80). Specifically, in the case adds document P12, the
inclination correction of the image is zero.
[0081] If neither of the corner portions on the front side and the
back side of the document is orthogonal, conveyance of the document
is stopped (S90).
[0082] In FIGS. 10 to 12 described above, a case where edges on the
front side and rear side of the apparatus of the documents P10,
P11, and P12 are parallel to the document conveyance direction F1
has been described. Next, referring to FIG. 17 to FIG. 22, a case
where the edges on the front side and rear side of the apparatus
are not parallel to the document conveyance direction F1 will be
described.
[0083] FIG. 17 shows a case of the document P10 with an orthogonal
cut section, and FIG. 18 is a diagram schematically showing
detection timings of the inclination sensor (R) 55, the inclination
sensor (F) 56, and the end detection sensor 57 in the case of the
document P10 shown in FIG. 17. The document P10 may be bound on the
right side or bound on the left side.
[0084] FIG. 19 shows a case of the document P11 whose cut section
on the rear side is inclined, and FIG. 20 is a diagram
schematically showing detection timings of the inclination sensor
(R) 55, the inclination sensor (F) 56, and the end detection sensor
57 in the case of the document P11 shown in FIG. 19. The document
P11 is usually bound on the right side.
[0085] FIG. 21 shows a case of the document P12 whose cut section
on the front side is inclined, and FIG. 22 is a diagram
schematically showing detection timings of the inclination sensor
(R) 55, the inclination sensor (F) 56, and the end detection sensor
57 in the case of the document P12 shown in FIG. 21. The document
P12 is usually bound on the left side.
[0086] Referring to FIGS. 17, 18 and 16, the document P10 is
conveyed (S10), and it is detected by the end detection sensor 57
that a front corner portion C1 of the document P10 includes a right
angle (S20 and S30). Next, as a front end P10f and a rear end P10r
of the document P10 sequentially pass by the inclination sensor (R)
55 and the inclination sensor (F) 56, widths W11 and W12 of the
document P10 along the conveyance direction being the same is
detected.
[0087] As a result, it is detected that the front end P11f of the
document P11 is orthogonal, and the amount of inclination of the
front end P11f is detected (S40). Next, inclination correction is
performed on a read image with reference to the front side of the
document P10 (S50). Specifically, in the case of this document P10,
the inclination of the image is obtained from the time difference
of passage of the front end P10f between the inclination sensor (R)
55 and the inclination sensor (F) 56.
[0088] Referring to FIGS. 19, 20 and 16, the document P11 is
conveyed (S10), and it is detected by the end detection sensor 57
that a front corner portion C1 of the document P11 includes a right
angle (S20 and S30). Next, as a front end P11f and a rear end P11r
of the document P11 sequentially pass by the inclination sensor (R)
55 and the inclination sensor (F) 56, widths W11 and W12 of the
document P11 along the conveyance direction being different is
detected.
[0089] However, since the corner portion C1 on the front side of
the document P11 includes a right angle, it is detected that the
front end P11f of the document P11 is orthogonal, and the amount of
inclination of the front end P11f is detected (S40). Next, the
inclination correction of the read image is performed with
reference to the front side of the document P11 (S50).
Specifically, in the case of this document P11, the inclination of
the image is obtained from the time difference of passage of the
front end P11f between the inclination sensor (R) 55 and the
inclination sensor (F) 56.
[0090] Referring to FIGS. 21, 22 and 16, the document P12 is
conveyed (S10), and it is detected by the end detection sensor 57
that a front corner portion C1 of the document P12 does not include
a right angle (S20 and S30). Next, it is detected that a corner
portion C2 of the document P12 on the rear side includes a right
angle (S60). Next, as a front end P12f and a rear end P12r of the
document P12 sequentially pass by the inclination sensor (R) 55 and
the inclination sensor (F) 56, widths W11 and W12 of the document
P12 along the conveyance direction being different is detected.
However, the end detection sensor 57 detects that a corner portion
C2 on the rear side of the document P12 includes a right angle
(S60).
[0091] As a result, it is determined that the rear end P12r is
orthogonal although the front end P12f of the document P12 is not
orthogonal (S70). Next, inclination correction of the read image is
performed with reference to the rear side of the document P12
(S80). Specifically, in the case of this document P12, the
inclination of the image is obtained from the time difference of
passage of the front end P12f between the inclination sensor (R) 55
and the inclination sensor (F) 56.
[0092] If neither of the corner portions on the front side and the
back side of the document is orthogonal, conveyance of the document
is stopped (S90).
[0093] As described above, the image forming apparatus 1 according
to the present embodiment determines whether the document set on
the tray by the user is inclined due to conveyance or an end
portion of the document (cut section) is oblique, and, in the case
where it is determined that the front end side of the document
includes a right angle, the amount of inclination is determined
immediately with reference to the leading end of the document.
Thus, the amount of inclination can he determined before the image
reading is completed, the time required by the correction process
is reduced, and appropriate inclination correction can be performed
for high-speed reading of a large number of documents.
[0094] To be noted, although the end detection sensor 57 is
disposed on the front side of the apparatus in the image forming
apparatus 1 described above, the end detection sensor 57 may be
disposed on the rear side of the apparatus as shown in FIG. 23.
Further, as shown in FIG. 24, the end detection sensor 57 may be
disposed to extend from the rear side to the front side of the
apparatus.
[0095] Further, although a case where cut surface is disposed on
the front side or the rear side of the document P10, P11, or P12 in
the conveyance direction has been described, whether the document
set on the tray by the user is inclined due to conveyance or the
end portion of the document (cut section) is oblique can be
determined similarly also in the case of a document P21 whose cut
section is disposed on the rear side of the apparatus as shown in
FIGS. 25 and 26.
[0096] Furthermore, in the image forming apparatus 1 described
above, when reading not only an image on the front surface of the
document but also an image on the back surface of the document,
image correction similar to the image correction performed on the
image on the front surface may be performed on the image on the
back surface.
[0097] Although embodiments of the present invention have been
described and illustrated in detail, the disclosed embodiments are
made for purposes of illustration and example only and not
limitation. The scope of the present invention should be
interpreted by terms of the appended claims. The scope of the
present invention is intended that all modifications within meaning
and scope equivalent to the claims are included.
* * * * *