U.S. patent application number 15/832197 was filed with the patent office on 2018-04-05 for image forming apparatus.
The applicant listed for this patent is CANON KABUSHIKI KAISHA. Invention is credited to Shinnosuke Iwadate, Teruhito Kai, Kenzo Kumagai, Hiroto Nishihara, Hiromi Shimura, Keita Takahashi.
Application Number | 20180097947 15/832197 |
Document ID | / |
Family ID | 55654972 |
Filed Date | 2018-04-05 |
United States Patent
Application |
20180097947 |
Kind Code |
A1 |
Takahashi; Keita ; et
al. |
April 5, 2018 |
IMAGE FORMING APPARATUS
Abstract
Provided is an image forming apparatus, including: a manual feed
tray on which a recording material is stacked; a first detecting
unit; a second detecting unit arranged on an upstream side of the
first detecting unit; a third detecting unit arranged on an
upstream side of the second detecting unit; a fourth detecting unit
detecting a length of the recording material; a display portion;
and a control portion determining a size of the recording material
based on detection results and causing the display portion to
display a first screen displaying the determined size, wherein the
control portion causes the display portion to display a second
screen for designating the size, when, among the first to third
detecting units, a detecting unit located on a downstream side does
not detect presence of the recording material and another detecting
unit located on an upstream side of the detecting unit, detects the
presence.
Inventors: |
Takahashi; Keita;
(Abiko-shi, JP) ; Iwadate; Shinnosuke;
(Toride-shi, JP) ; Kai; Teruhito; (Kashiwa-shi,
JP) ; Nishihara; Hiroto; (Tsukuba-shi, JP) ;
Kumagai; Kenzo; (Toride-shi, JP) ; Shimura;
Hiromi; (Toride-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CANON KABUSHIKI KAISHA |
Tokyo |
|
JP |
|
|
Family ID: |
55654972 |
Appl. No.: |
15/832197 |
Filed: |
December 5, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14857013 |
Sep 17, 2015 |
9871934 |
|
|
15832197 |
|
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|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65H 2553/82 20130101;
H04N 1/00482 20130101; B65H 2511/51 20130101; B65H 2511/10
20130101; B65H 2511/52 20130101; H04N 2201/0094 20130101; B65H
2511/515 20130101; B65H 1/266 20130101; B65H 7/02 20130101; B65H
2511/51 20130101; B65H 2220/01 20130101; B65H 2511/515 20130101;
B65H 2220/01 20130101; B65H 2511/10 20130101; B65H 2220/03
20130101; B65H 2511/10 20130101; B65H 2220/04 20130101; B65H
2511/52 20130101; B65H 2220/03 20130101 |
International
Class: |
H04N 1/00 20060101
H04N001/00; B65H 1/26 20060101 B65H001/26; B65H 7/02 20060101
B65H007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 8, 2014 |
JP |
2014-207387 |
Claims
1. An image forming apparatus comprising: a manual feed tray on
which recording material is to be manually stacked; a first
detector configured to detect a presence or absence of the
recording material on the manual feed tray; a second detector
arranged on an upstream side of the first detector in a conveyance
direction of the recording material, the second detector configured
to detect a presence or absence of the recording material on the
manual feed tray; a third detector arranged on an upstream side of
the second detector in the conveyance direction of the recording
material, the third detector configured to detect a presence or
absence of the recording material on the manual feed tray; a
display portion configured to display information; and a controller
configured to determine a size of the recording material based on
detection results of the first detector, the second detector and
the third detector, and to cause the display portion to display the
determined size of the recording material, wherein the controller
is further configured to cause the display portion to display a
message representing that the size of the recording material has
not been detected in a case that, among the first detector, the
second detector and the third detector, a detection result of a
downstream-side detector located on a downstream side in the
conveyance direction does not represent the presence of the
recording material and a detection result of an upstream-side
detector located on an upstream side of the downstream-side
detector with respect to the conveyance direction represents the
presence of the recording material.
2. The image forming apparatus according to claim 1, wherein the
controller is further configured to cause the display portion to
display the message in a case that detection results of the first
detector and the third detector represent the presence of the
recording material and a detection result of the second detector
does not represent the presence of the recording material.
3. The image forming apparatus according to claim 1, wherein the
controller is further configured to cause the display portion to
display the message in a case that a detection result of the first
detector does not represent the presence of the recording material
and a detection result of the second detector represents the
presence of the recording material.
4. The image forming apparatus according to claim 1, wherein the
controller is further configured to cause the display portion to
display another message for prompting to check the recording
material on the manual feed tray along with the message.
5. The image forming apparatus according to claim 1, wherein the
controller is further configured to cause the display portion to
display the determined size of the recording material in a case
that detection results of all of the first detector, the second
detector and the third detector represent the presence of the
recording material.
6. The image forming apparatus according to claim 1, wherein the
controller is further configured to cause the display portion to
display the determined size of the recording material in a case
that, among detection results of the first detector, the second
detector and the third detector, a detection result of a
downstream-side detector located on a downstream side in the
conveyance direction represents the presence of the recording
material and a detection result of an upstream-side detector
located on an upstream side of the downstream-side detector with
respect to the conveyance direction does not represent the presence
of the recording material.
7. The image forming apparatus according to claim 6, further
comprising a fourth detector configured to detect a length of the
recording material on the manual feed tray in a direction
orthogonal to the conveyance direction, wherein the controller is
configured to determine the size of the recording material based on
the detection results of the first detector, the second detector,
the third detector, and the fourth detector.
8. The image forming apparatus according to claim 7, wherein: the
manual feed tray has regulating plates configured to regulate both
end portions of the recording material in the direction orthogonal
to the conveyance direction, and the fourth detector is configured
to output a value corresponding to positions of the regulating
plates in conjunction with an operation of the regulating plates.
Description
[0001] This application is a Continuation of U.S. application Ser.
No. 14/857,013, filed Sep. 17, 2015, which claims the benefit of
Japanese Patent Application No. 2014-207387, filed Oct. 8, 2014,
which are hereby incorporated by reference herein in their
entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to an image forming apparatus
configured to form an image on a fed sheet.
Description of the Related Art
[0003] Hitherto, an image forming apparatus such as a copying
machine or a printer includes a sheet feeding cassette in an
apparatus main body so that copying or printing can be carried out
for a sheet continuously. A size and a type of the sheet to be used
greatly depend on an environment in which a user uses the image
forming apparatus. To address such a requirement, the image forming
apparatus is provided with a plurality of sheet feeding cassettes.
Even when the image forming apparatus includes a plurality of sheet
feeding cassettes, there may arise a demand to execute the copying
or printing for a sheet different from the sheet set on each of the
sheet feeding cassettes. On the assumption that there may arise
such a demand, the image forming apparatus is configured as
follows. Specifically, the image forming apparatus also includes a
manual feed tray besides the sheet feeding cassettes so that a
desired sheet can be set with ease.
[0004] In order to feed and convey the sheet set on the manual feed
tray and form an image in an appropriate position, the size of the
sheet needs to be known, and it is necessary for the user to input
the size of the sheet through an operation portion. In this case,
each time the user sets a sheet on the manual feed tray, the user
needs to set the sheet size through the operation portion, and
hence there has been a fear for a decrease in usability. In
contrast, there has been proposed such a configuration that a
plurality of sensors is arranged on the manual feed tray in a
direction of conveying the sheet (Japanese Patent Application
Laid-Open No. 2004-231410). A length of the sheet placed on the
manual feed tray in the conveyance direction is detected by the
plurality of sensors. Based on a value acquired from a volume
sensor mounted to a movable guide on the manual feed tray, a length
of the sheet in a direction orthogonal to the conveyance direction
is detected. Based on the detection results, the image forming
apparatus automatically detects the sheet size. In the image
forming apparatus configured to automatically detect the sheet
size, in order to further enhance operability of the user, the
sheet size is determined without displaying a screen for checking
the automatically detected sheet size on the operation portion.
[0005] The related-art image forming apparatus has the following
problems. When a sensor arranged in the conveyance direction of the
sheet fails, and a sheet to be subjected to copying or printing is
set on the manual feed tray, the sheet size of the sheet set on the
manual feed tray is erroneously detected. For example, a sensor
arranged in the conveyance direction of the sheet for detecting a
sheet having the size of an A3 length (420 mm) may fail and be
stuck in an on state. In this case, even when the user sets a sheet
having an A4 size (210 mm) on the manual feed tray, the image
forming apparatus determines that the sheet size is the A3 length.
As a result, the image forming is carried out so as to be suitable
for the size of the A3 length. However, the fed sheet is the sheet
having the A4 length, and hence the size of a formed image is
larger than the size of the fed sheet. As a result, remaining toner
that has not been transferred onto the sheet is adhered to members
of an image forming portion, which causes an image failure such as
marking back during image forming processing on the subsequent
sheet.
[0006] The sensor arranged in the conveyance direction of the sheet
may fail and be stuck in an off state. In this case, even when the
user sets a sheet having the A3 size on the manual feed tray, the
image forming apparatus determines that the sheet size is the A4
length. As a result, the sheet size determined by the image forming
apparatus is smaller in length than the sheet size of the fed sheet
in the conveyance direction, and it may be determined that a paper
jam occurs.
SUMMARY OF THE INVENTION
[0007] The present invention has an object to prevent an image
failure or a paper jam caused by an erroneous detection when a
sheet size is detected by a manual feed tray.
[0008] In order to solve the above-mentioned problem, one
embodiment of the present invention includes the following
configuration.
[0009] There is provided an image forming apparatus, including: a
manual feed tray on which a recording material is to be manually
stacked; a first detecting unit configured to detect presence or
absence of the recording material on the manual feed tray; a second
detecting unit arranged on an upstream side of the first detecting
unit in a conveyance direction of the recording material, the
second detecting unit configured to detect presence or absence of
the recording material on the manual feed tray; a third detecting
unit arranged on an upstream side of the second detecting unit in
the conveyance direction, the third detecting unit configured to
detect presence or absence of the recording material on the manual
feed tray; a fourth detecting unit configured to detect a length of
the recording material on the manual feed tray in a direction
orthogonal to the conveyance direction; a display portion
configured to display information; and a control portion configured
to determine a size of the recording material based on detection
results of the first detecting unit, the second detecting unit, the
third detecting unit and the fourth detecting unit, and control
portion causing the display portion to display a first screen
displaying the determined size of the recording material, wherein
the control portion causes the display portion to display a second
screen for designating the size of the recording material, when,
among the first detecting unit, the second detecting unit and the
third detecting unit, a detecting unit located on a downstream side
in the conveyance direction does not detect the presence of the
recording material and another detecting unit located on an
upstream side of the detecting unit in the conveyance direction,
which does not detect the presence of the recording material,
detects the presence of the recording material.
[0010] According to the one embodiment of the present invention, it
is possible to prevent the image failure or the paper jam caused by
the erroneous detection when the sheet size is detected by the
manual feed tray.
[0011] Further features of the present invention will become
apparent from the following description of exemplary embodiments
with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a system block diagram of an image forming
apparatus according to a first embodiment and a second embodiment
of the present invention.
[0013] FIG. 2 is a view for illustrating a configuration of the
image forming apparatus according to the first embodiment and the
second embodiment.
[0014] FIG. 3A is a top view of a manual feed tray according to the
first embodiment and the second embodiment.
[0015] FIG. 3B is a graph for showing a relationship between an AD
value and a sheet size.
[0016] FIG. 4A is a diagram for illustrating a manual feed sheet
size display screen according to the first embodiment.
[0017] FIG. 4B is a diagram for illustrating a manual feed sheet
size designation screen.
[0018] FIG. 5 is a flowchart for displaying the manual feed sheet
size display screen according to the first embodiment.
[0019] FIG. 6 is a flowchart for determining a normal operation of
size detection according to the first embodiment.
[0020] FIG. 7 is a diagram for illustrating a state of a sheet on
the manual feed tray according to the first embodiment.
[0021] FIG. 8 is a flowchart for illustrating a display screen
switching operation according to the first embodiment.
[0022] FIG. 9 is a diagram for illustrating a manual feed size
detection alarm screen according to the second embodiment.
[0023] FIG. 10 is a flowchart for displaying the manual feed size
detection alarm screen according to the second embodiment.
[0024] FIG. 11 is a diagram for illustrating a screen setting
screen when a manual feed size is indefinite according to a third
embodiment of the present invention.
[0025] FIG. 12 is a flowchart for displaying a screen setting
screen when a manual feed size is indefinite according to the third
embodiment.
DESCRIPTION OF THE EMBODIMENTS
[0026] Now, embodiments of the present invention are described in
detail with reference to the drawings.
First embodiment
[0027] (Image Forming Apparatus)
[0028] FIG. 1 is a system block diagram of an image forming
apparatus according to a first embodiment of the present invention,
and FIG. 2 is a sectional view of an image forming apparatus 100
and a scanner portion 101 according to this embodiment. With
reference to FIG. 1 and FIG. 2, a basic configuration is described.
A control portion 300 illustrated in FIG. 1 includes a CPU 301, a
ROM 302, a RAM 303, and an EEPROM 304. When, for example, an
instruction (hereinafter referred to as "job") to start a printing
operation is input to the CPU 301 through a user interface (UI) of
an operation portion 330 (hereinafter referred to simply as
"operation portion 330"), the CPU 301 starts the printing
operation. The CPU 301 can drive and control, via an I/O 307, a
conveyance motor 145, a fixing motor 173, a conveyance motor 146, a
manual feed conveyance motor 147, a discharge motor 148, and a
discharge motor 149. Further, the CPU 301 can detect, via the I/O
307, an input signal input from a conveyance sensor 171, a
registration sensor 160, a sheet feeding sensor 152, a discharge
sensor 195, or a discharge sensor 197.
[0029] Further, the CPU 301 can detect, via the I/O 307, an input
signal input from a manual feed sheet presence sensor 214, a manual
feed sheet length sensor 218, or a manual feed sheet length sensor
219. The sheet length represents a length of a sheet in a
conveyance direction thereof. The CPU 301 can detect, via the I/O
307, an input signal input from a manual feed sheet width sensor
217. In addition, the CPU 301 can also receive a job input from a
network I/F 314 or a facsimile I/F 315. For example, the CPU 301 is
connected to a network for communicating to/from an external
apparatus, and receives a job from the external apparatus via the
network I/F 314. Further, for example, the CPU 301 is connected to
a telephone line for receiving FAX, and receives FAX via the
facsimile I/F 315.
[0030] The CPU 301 includes an image processing portion 316
configured to process an image corresponding to the job received
from the operation portion 330 or the like, and executes image
processing such as expansion and rotation of the image. Further,
the CPU 301 can control an image forming portion 320. The image
forming portion 320 can control drive and supply of a high voltage
to a process unit 120 indicated by the dotted frame in FIG. 2, a
transfer belt 130, a secondary transfer portion 140, and the like,
and can control a laser scanner unit 110 indicated by the dotted
frame in FIG. 2. Further, the image forming portion 320 can control
a temperature of a heater of a fixing device 170 illustrated in
FIG. 2. The scanner portion 101 carries out an operation for
reading an original when copying is executed. The CPU 301 includes
a timer, and carries out various types of timing control by using
the timer to measure the time.
[0031] With reference to FIG. 1 and FIG. 2, a basic image forming
operation is described. When receiving a job from the operation
portion 330, the CPU 301 analyzes the received job, and starts a
printing operation. The CPU 301 drives, via the I/O 307, the
conveyance motor 145 serving as a drive source of a cassette pickup
roller 151. Thereby, the cassette pickup roller 151 is driven to
rotate and sheets within a sheet feeding cassette 150 are fed and
conveyed one by one. At this time, the CPU 301 uses the sheet
feeding sensor 152 to monitor whether or not a sheet feeding
operation has been normally carried out for the sheets.
[0032] Sheet conveyance from the manual feed tray 210 is described.
The CPU 301 operates as follows when receiving an instruction to
convey a sheet on the manual feed tray 210 from the operation
portion 330 with the sheets serving as recording materials being
stacked on the manual feed tray 210. Specifically, the CPU 301
drives the manual feed conveyance motor 147 via the I/O 307 to
rotate manual feed pickup rollers 211. When rotation of the manual
feed pickup rollers 211 is started, the sheets on the manual feed
tray 210 are fed and conveyed one by one. In the same manner as in
the case of sheet feeding from the sheet feeding cassette 150, the
CPU 301 monitors the registration sensor 160 to determine whether
or not the sheet feeding operation has been normally carried out.
Further, the manual feed sheet presence sensor 214 serving as a
first detecting unit determines whether or not a sheet is set on
the manual feed tray 210. A configuration of the manual feed tray
210 is described later in detail.
[0033] The CPU 301 causes the process unit 120 to start the image
forming operation so as to be in time with arrival of the sheet at
the secondary transfer portion 140. The process unit 120 includes a
photosensitive drum, a developing device, a charging roller, and a
photosensitive drum cleaner. In the process unit 120, after a
surface of the photosensitive drum is charged, an electrostatic
latent image is formed on the photosensitive drum by a laser beam
emitted from the laser scanner unit 110. The electrostatic latent
image formed on the photosensitive drum is developed on the
photosensitive drum by the toner within the developing device, and
becomes a toner image. After that, the toner image formed on the
photosensitive drum is applied with a primary transfer voltage in a
primary transfer portion 121 (illustrated by the dotted frame), and
the toner image is transferred onto the transfer belt 130. The
toner image transferred onto the transfer belt 130 is conveyed to
the secondary transfer portion 140 by rotation of the transfer belt
130.
[0034] Further, the CPU 301 monitors the registration sensor 160 to
detect a position of the sheet conveyed by conveyance rollers 153,
conveyance rollers 154, and conveyance rollers 155. Then, in
consideration of a timing at which a leading edge of the sheet
reaches the registration sensor 160, the CPU 301 controls the
conveyance of the sheet so that the leading edge of the sheet and
the leading edge of the toner image on the transfer belt 130 are
aligned with each other at the secondary transfer portion 140. For
example, when the sheet has reached the registration sensor 160
earlier than the toner image, the CPU 301 stops the sheet for a
predetermined period of time at conveyance rollers 161 and restarts
the conveyance of the sheet thereafter. In the secondary transfer
portion 140, the CPU 301 applies a secondary transfer voltage to
the sheet and the toner image that have reached the secondary
transfer portion 140, to thereby transfer the toner image onto the
sheet.
[0035] The sheet having the toner image transferred thereon is
conveyed to the fixing device 170 via a conveyor belt 190. In the
fixing device 170, the unfixed toner image that has transferred
onto the sheet is heated and fixed to the sheet. After that, the
sheet is further conveyed to a downstream-side part in the
conveyance direction of the sheet. When the leading edge of the
sheet subjected to the fixing reaches the conveyance sensor 171,
the CPU 301 carries out the following operation. Specifically, the
CPU 301 determines, based on contents of the job designated through
the operation portion 330 in advance, which conveyance path of a
sheet conveyance path 230, a sheet conveyance path 231, and a sheet
conveyance path 234 the sheet is to be conveyed by conveyance
rollers 162. The CPU 301 switches a conveyance destination of the
sheet by switching a conveyance flapper 172 and a conveyance
flapper 182.
[0036] Specifically, when the job designated through the operation
portion 330 is a double-sided print job, and when the sheet is to
be discharged with the printed surface facing down with respect to
a discharge port 200, the CPU 301 switches the conveyance flapper
172 in order to convey the sheet to the sheet conveyance path 230.
Further, when the sheet is to be discharged onto a discharge port
196 or a discharge port 199 at a time of one-sided printing or
double-sided printing, the CPU 301 conveys the sheet to the sheet
conveyance path 231 by switching the conveyance flapper 182. In
addition, when the job designated through the operation portion 330
is a discharge instruction with respect to the discharge port 200,
the CPU 301 conveys the sheet to the sheet conveyance path 234 by
switching the conveyance flapper 172 and the conveyance flapper
182.
[0037] The sheet conveyed to the sheet conveyance path 231 is
further conveyed to a downstream side in the conveyance direction
of the sheet (hereinafter referred to as "downstream side") by
conveyance rollers 232. Subsequently, the sheet is conveyed to a
sheet conveyance path 181, and conveyed toward the discharge port
196 and the discharge port 199. The sheet conveyed to the sheet
conveyance path 181 is conveyed by discharge rollers 241 and
discharge rollers 242 driven by the discharge motor 148. When the
job designated through the operation portion 330 is a discharge
instruction with respect to the discharge port 196, the CPU 301
conveys the sheet to a conveyance path 193 by switching a flapper
183, to thereby discharge the sheet onto the discharge port 196 by
discharge rollers 243. When the job designated through the
operation portion 330 is a discharge instruction with respect to
the discharge port 199, the CPU 301 switches the flapper 183 toward
a conveyance path 184. Subsequently, the CPU 301 conveys the sheet
to a conveyance path 198 by discharge rollers 244, discharge
rollers 245, and discharge rollers 246 that are driven by the
discharge motor 149, to thereby discharge the sheet onto the
discharge port 199.
[0038] When the sheet is discharged onto the discharge port 200
with the printed surface facing down at the time of carrying out
the one-sided printing, the CPU 301 conveys the sheet to the sheet
conveyance path 230. Then, at a timing at which a trailing edge of
the sheet passes through reversal rollers 163, the rollers such as
the reversal rollers 163 and double-sided conveyance rollers 164
are driven to reversely rotate so that the sheet is conveyed toward
discharge rollers 180, to thereby the sheet is discharged onto the
discharge port 200. When performing the double-sided printing, the
sheet is conveyed to the sheet conveyance path 230. Then, the sheet
is conveyed to a double-sided turnover conveyance path 233 by the
double-sided conveyance rollers 164, 165, 166, 179, and 168.
Subsequently, at a timing at which the trailing edge of the sheet
passes through the double-sided conveyance rollers 179, a
double-sided turnover flapper 178 is switched toward double-sided
conveyance rollers 169, and the rollers such as the double-sided
conveyance rollers 168 and 179 are driven to reversely rotate.
Subsequently, the sheet is conveyed by the double-sided conveyance
rollers 169, 175, 176, and 177, to be passed to the conveyance
rollers 155. After all the jobs are finished, the CPU 301 displays
on the operation portion 330 that the jobs have been finished.
[0039] The operation portion 330 includes an input key group 331
(illustrated by the dotted frame) to be used when a user inputs
information, and a start key 332 to be depressed when the image
forming operation is started. Further, the operation portion 330
includes a stop key 333 to be depressed when the image forming
operation or the like is interrupted, a display portion 334 serving
as a display unit, and a sleep button 335. The sleep button 335 of
the operation portion 330 is depressed when shifting to a sleep
mode in which the image forming apparatus 100 is in a power saving
state to reduce power consumption. Moreover, the sleep button 335
is depressed when the image forming apparatus 100 recovers from the
sleep mode. A user setting button 336 is depressed when a screen
for displaying a screen setting screen 1200 (refer to FIG. 11) is
displayed on the display portion 334. The basic image forming
operation is merely an example, and the present invention is not
limited to the above-mentioned configuration.
[0040] (Manual Feed Tray)
[0041] FIG. 3A is a top view of the manual feed tray 210, and a
main body of the image forming apparatus 100 is located on the left
side of FIG. 3A. When a bundle of sheets (hereinafter sometimes
referred to simply as "sheets") is set on the manual feed tray 210,
the sheets are separated from the bundle of sheets one by one by
the manual feed pickup rollers 211, to be conveyed. When the sheets
are set on the manual feed tray 210, the manual feed sheet presence
sensor 214 outputs the ON signal. An ON signal is input from the
manual feed sheet presence sensor 214 to the CPU 301, and the CPU
301 determines that the sheet is present on the manual feed tray
210. The bundle of sheets set on the manual feed tray 210 is
sandwiched at both end portions of the bundle of sheets in the
conveyance direction of the sheet by side-regulating guides 212 and
213 serving as regulating plates. This prevents the sheet from
being skew fed and conveyed while the sheet is conveyed by the
manual feed pickup rollers 211. By causing the side-regulating
guides 212 and 213 to slide in directions indicated by arrows 215
and 216 in FIG. 3A, it is possible to prevent the sheet from being
skew fed even when the sheet having an arbitrary sheet width is
set. The sheet width represents the length of the sheet in a
direction orthogonal to the conveyance direction. In addition, the
side-regulating guides 212 and 213 are coupled to each other
through the manual feed sheet width sensor 217 serving as a fourth
detecting unit and a link member (not shown). The manual feed sheet
width sensor 217 outputs a signal (AD value) corresponding to
positions of the side-regulating guides 212 and 213 to the CPU 301
in conjunction with operations of the side-regulating guides 212
and 213.
[0042] The CPU 301 detects the sheet width based on the signal (AD
value) input from the manual feed sheet width sensor 217. The
manual feed sheet length sensor 218 serving as a second detecting
unit and the manual feed sheet length sensor 219 serving as a third
detecting sensor are, for example, flag-type sensors, and detect
the length of the sheet set on the manual feed tray 210 (refer to
FIG. 7). The sheet length represents the length of the sheet in the
conveyance direction. The flag-type sensors include, for example,
flags 218a and 219a and photointerrupters 218b and 219b (refer to
FIG. 7). When the sheet is stacked on the manual feed tray 210, the
sheet abuts against the flag, the flag consequently turns, and the
flag brings the photointerrupter into a light shielding state. For
example, in this embodiment, when the photointerrupter is in the
light shielding state, the manual feed sheet length sensors 218 and
219 output ON signals. When a sheet is not stacked on the manual
feed tray 210, the flags do not turn, and the flags do not shield
the light, and the photointerrupters are in a light transmission
state. For example, in this embodiment, when the photointerrupters
are in the light transmission state, the manual feed sheet length
sensors 218 and 219 output OFF signals. In this embodiment, the
manual feed sheet presence sensor 214 also includes a flag 214a and
a photointerrupter 214b (refer to FIG. 7), but the manual feed
sheet presence sensor 214 may be a sensor of another type.
[0043] (Sheet Size Detection)
[0044] With reference to FIG. 3B and Table 1, a method of detecting
a size of the sheet set on the manual feed tray 210 is described.
FIG. 3B is a graph for showing a relationship between the signal
(AD value) output from the manual feed sheet width sensor 217 based
on the positions of the side-regulating guides 212 and 213 and a
width of the sheet to be detected in actuality (paper width).
Specifically, in FIG. 3B, the horizontal axis indicates the AD
value (such as 0.times.3D4) output by the manual feed sheet width
sensor 217, while the vertical axis indicates the size of the sheet
(paper width) (such as A4 width (297 mm)). The manual feed sheet
width sensor 217 is a sensor configured to output, specifically, a
10-bit digital value and to output, substantially linearly, output
values 0.times.000 to 0.times.400 in the hexadecimal format.
[0045] As shown in FIG. 3B, the output value 0.times.320 of the
manual feed sheet width sensor 217 represents 210 mm as the A4R
width, the output value 0.times.384 similarly represents 257 mm as
the B4R width, and the output value 0.times.3D4 represents 297 mm
as the A4 width. In other words, for example, when the AD value
0.times.320 is input from the manual feed sheet width sensor 217,
the CPU 301 determines that the paper width of the sheet set on the
manual feed tray 210 is 210 mm. The CPU 301 detects the sheet width
from the output value (AD value) of the manual feed sheet width
sensor 217, and detects the sheet length from the output values of
the manual feed sheet length sensors 218 and 219. Then, the CPU 301
refers to Table 1 to determine the size of the sheet from those
detection results.
TABLE-US-00001 TABLE 1 Manual Manual Manual feed feed feed sheet
sheet sheet Manual presence length length feed sheet Sheet Sheet
sensor sensor sensor width Size width length 214 218 219 sensor 217
A5 210 148 ON OFF OFF 0x320 .+-. 0x10 B5 257 182 ON OFF OFF 0x384
.+-. 0x10 A4 297 210 ON OFF OFF 0x3D4 .+-. 0x10 A5R 148 210 ON OFF
OFF 0x258 .+-. 0x10 B5R 182 257 ON ON OFF 0x2E4 .+-. 0x10 A4R 210
297 ON ON OFF 0x320 .+-. 0x10 B4 257 364 ON ON ON 0x384 .+-. 0x10
A3 297 420 ON ON ON 0x3D4 .+-. 0x10
[0046] Table 1 shows the size of the sheet, the sheet width (mm),
and the sheet length (mm) from the left in this order, and shows
the information in which the sizes of the sheet are associated with
the detection results obtained by the respective sensors. In
addition, Table 1 shows the detection result from the manual feed
sheet presence sensor 214, the detection results from the manual
feed sheet length sensors 218 and 219, and the detection result
from the manual feed sheet width sensor 217. The manual feed sheet
width sensor 217 outputs the AD value to the CPU 301, and the other
sensors output an ON signal or an OFF signal to the CPU 301.
[0047] The CPU 301 refers to those detection results from the
sensors and Table 1, to thereby determine the size of the sheet. In
other words, the CPU 301 functions as a determination unit
configured to determine the size of the sheet. For example, it is
assumed that the manual feed sheet presence sensor 214 outputs the
ON signal, the manual feed sheet length sensor 218 outputs the OFF
signal, the manual feed sheet length sensor 219 outputs the OFF
signal, and the manual feed sheet width sensor 217 outputs the AD
value 0.times.320.+-.0.times.10. In this case, the CPU 301
determines that the sheet set on the manual feed tray 210 is an
A5-size sheet based on the detection results from the respective
sensors and the information of Table 1. In the same manner, it is
assumed that the manual feed sheet presence sensor 214 outputs the
ON signal, the manual feed sheet length sensor 218 outputs the ON
signal, the manual feed sheet length sensor 219 outputs the OFF
signal, and the manual feed sheet width sensor 217 outputs the AD
value 0.times.320.+-.0.times.10. In this case, the CPU 301
determines that the sheet set on the manual feed tray 210 is an
A4R-size sheet to be fed by a short edge feed of A4.
[0048] As shown in Table 1, even when the output value of the
manual feed sheet width sensor 217 is the same, it is possible to
determine that the size is different based on a difference in the
detection results from the manual feed sheet length sensors 218 and
219. For example, even when the output value of the manual feed
sheet width sensor 217 is the same AD value
0.times.320.+-.0.times.10, the size of the sheet can be
distinguished between A5 and A4R based on the detection results
from the manual feed sheet length sensors 218 and 219.
[0049] Even when the detection results from the manual feed sheet
length sensors 218 and 219 are the same, the sheet size is
distinguished as long as the output value of the manual feed sheet
width sensor 217 is different. For example, even when the detection
results from the manual feed sheet length sensors 218 and 219 are
OFF, the CPU 301 can make the following determination based on the
AD value of the manual feed sheet width sensor 217. For example,
the size of the sheet is determined as A5, B5, A4, and A5R when the
AD value of the manual feed sheet width sensor 217 is
0.times.320.+-.0.times.10, 0.times.384.+-.0.times.10,
0.times.3D4.+-.0.times.10, and 0.times.258.+-.0.times.10,
respectively.
[0050] (Manual Feed Sheet Size Display Screen)
[0051] With reference to FIG. 4A and FIG. 4B, a screen displayed on
the operation portion 330 in order to prompt the user to check the
sheet size set on the manual feed tray 210 and designate the sheet
size is described. FIG. 4A is a manual feed sheet size display
screen 500, which is a first screen displayed on the display
portion 334 of the operation portion 330. The manual feed sheet
size display screen 500 of FIG. 4A is displayed on the display
portion 334 of the operation portion 330 in response to a state in
which the sheet is set on the manual feed tray 210, and the sheet
size is determined by the CPU 301. For example, in a process of
S708 of FIG. 5 or a process of S909 of FIG. 8, the CPU 301 displays
the manual feed sheet size display screen 500 on the display
portion 334 of the operation portion 330.
[0052] Specifically, the CPU 301 determines the size of the sheet
set on the manual feed tray 210, and displays the determined size
of the sheet on the display portion 334. In this manner, the
display screen 500 prompts the user to check the size of the sheet
set on the manual feed tray 210. Referring to FIG. 5 and FIG. 8, a
method of detecting the size of the sheet set on the manual feed
tray 210 is described later. When the size of the sheet set on the
manual feed tray 210 matches a displayed size 501 displayed on the
manual feed sheet size display screen 500, an OK button 503 is
depressed. When the size of the sheet set on the manual feed tray
210 does not match the displayed size 501 displayed on the manual
feed sheet size display screen 500, a change button 502 is
depressed.
[0053] (Manual Feed Sheet Size Designation Screen)
[0054] FIG. 4B is a manual feed sheet size designation screen 600,
which is a second screen displayed on the display portion 334 of
the operation portion 330. The manual feed sheet designation screen
600 is displayed on the operation portion 330 when an arbitrary
size of the sheet is designated by the user. For example, the
manual feed sheet size designation screen 600 is displayed when the
change button 502 is depressed on the manual feed sheet size
display screen 500 of FIG. 4A. Moreover, when the size of the sheet
cannot be determined by the respective sensors of the manual feed
tray 210 (S910 of FIG. 8), the manual feed sheet size designation
screen 600 is also displayed on the operation portion 330. When the
manual feed sheet size designation screen 600 is displayed on the
display portion 334 of the operation portion 330, the size of the
sheet is selected by the user depressing any of the buttons of the
size designation buttons 601 (indicated by the broken-line frame).
In FIG. 4B, as an example, the A4 size is designated. After the
sheet size is selected, the sheet size of the sheet set on the
manual feed tray 210 is determined when the user depresses the OK
button 602. The image forming apparatus 100 carries out a
subsequent image forming operation based on the sheet size
designated through the manual feed sheet size designation screen
600. The sheet size designated through the sheet size designation
screen 600 is stored, for example, in the RAM 303.
[0055] (Processing from Setting of Sheet to Displaying of Manual
Feed Sheet Size Display Screen)
[0056] FIG. 5 is a basic flowchart for illustrating processing from
setting of the sheet on the manual feed tray 210 to displaying of
the manual feed sheet size display screen 500 on the operation
portion 330. This processing is generally carried out. In order to
compare the general processing of FIG. 5 with the processing of
FIG. 8 according to this embodiment, the general processing of FIG.
5 is first described. In S701 (a step is indicated as "S"), the CPU
301 determines whether or not the manual feed sheet presence sensor
214 outputs the ON signal. While the CPU 301 is operating, the CPU
301 always monitors the output (ON or OFF) of the manual feed sheet
presence sensor 214, and the same holds true for FIG. 6 and FIG.
8.
[0057] In S701, when the CPU 301 determines that the manual feed
sheet presence sensor 214 outputs the OFF signal, the CPU 301
repeats the processing of S701. In S701, when the CPU 301
determines that the manual feed sheet presence sensor 214 outputs
the ON signal, the processing proceeds to S702. In S702, the CPU
301 stores the output value of the manual feed sheet width sensor
217 as a variable AdVal (AdVal=output value of manual feed sheet
width sensor 217). The variable AdVal is a variable for storing a
value to be stored in the RAM 303. In S703, the CPU 301 stores the
output value of the manual feed sheet length sensor 218 as a
variable L1Val (L1Val=output value of manual feed sheet length
sensor 218). In S704, the CPU 301 stores the output value of the
manual feed sheet length sensor 219 as a variable L2Val
(L2Val=output value of manual feed sheet length sensor 219). Each
of L1Val and L2Val is a variable for storing a value to be stored
in the RAM 303. In the following description, the variable for
storing the value to be stored in the RAM 303 is referred to simply
as "variable of the RAM 303".
[0058] In S705, the CPU 301 compares the respective values stored
as the variables in the RAM 303 in the processing of S702 to S704
with Table 1 to determine whether or not Table 1 includes a
suitable size. When the CPU 301 determines that Table 1 includes a
suitable size in S705, the CPU 301 stores information (such as A5)
of the suitable size as PapSize serving as the variable in the RAM
303 (PapSize=suitable size) in S706. When the CPU 301 determines
that Table 1 does not include a suitable size in S705, the CPU 301
stores information (for example, "indefinite") indicating that the
size is indefinite as the variable PapSize (PapSize=indefinite) in
S707.
[0059] In S708, based on the information of the size of the sheet
stored as the variable PapSize in S706 or S707, the CPU 301
displays the manual feed sheet size display screen 500 on the
display portion 334 of the operation portion 330, and brings the
processing to an end. In other words, based on the information of
the size of the sheet stored as the variable PapSize in S706 or
S707, the manual feed sheet size display screen 500 described with
reference to FIG. 4A is displayed on the display portion 334 of the
operation portion 330. Specifically, the CPU 301 displays the
information (such as "A4") of the size of the sheet, which is
stored as the variable PapSize in S706, on the displayed size 501
of the manual feed sheet size display screen 500. Alternatively,
the CPU 301 displays the information (such as "indefinite")
indicating that the size of the sheet is indefinite, which is
stored as the variable PapSize in S707, on the displayed size 501
of the manual feed sheet size display screen 500.
[0060] (Processing of Determining Whether or Not Detection of Sheet
Size by Manual Feed Tray is Normal)
[0061] FIG. 6 is a flowchart for determining whether or not the
processing of detecting the size of the sheet set on the manual
feed tray 210 can be normally carried out. In this embodiment, when
the sheet is set on the manual feed tray 210, the processing
illustrated in FIG. 6 is carried out. In S801, the CPU 301
determines whether or not the manual feed sheet presence sensor 214
outputs the OFF signal. Moreover, the CPU 301 resets and starts the
timer. In S801, when the CPU 301 determines that the manual feed
sheet presence sensor 214 outputs the OFF signal, the processing
proceeds to S802. In S802, the CPU 301 determines whether or not
the manual feed sheet length sensor 218 outputs the ON signal. When
the CPU 301 determines that the manual feed sheet length sensor 218
outputs the ON signal, the processing proceeds to S804. In S802,
when the CPU 301 determines that the manual feed sheet presence
sensor 218 outputs the OFF signal, the processing proceeds to S803.
In S803, the CPU 301 determines whether or not the manual feed
sheet length sensor 219 outputs the ON signal. When the CPU 301
determines that the manual feed sheet length sensor 218 outputs the
ON signal, the processing proceeds to S804. In S803, when the CPU
301 determines that the manual feed sheet presence sensor 219
outputs the OFF signal, the processing proceeds to S806. In this
case, none of the sensors arranged on the manual feed tray 210 in
the conveyance direction of the sheet detects the presence of the
sheet, and the CPU 301 determines that the size detection for the
sheet is normal.
[0062] In S804, by referring to the timer, the CPU 301 determines
whether or not a predetermined period of time T1 has elapsed. When
the CPU 301 determines that the predetermined period of time T1 has
not elapsed, the CPU 301 repeats the processing of S804. In S804,
when the CPU 301 determines that the predetermined period of time
T1 has elapsed, the processing proceeds to S805. In S805, the CPU
301 again determines whether or not the manual feed sheet presence
sensor 214 outputs the ON signal. When the CPU 301 determines that
the manual feed sheet presence sensor 214 outputs the ON signal,
the processing proceeds to S806. In this case, among the sensors
arranged on the manual feed tray 210 in the conveyance direction of
the sheet, there is no sensor in the OFF state and arranged on the
downstream side in the conveyance direction with respect to a
sensor in the ON state. Therefore, the CPU 301 determines that the
size detection for the sheet is normal. In S805, when the CPU 301
determines that the manual feed sheet presence sensor 214 outputs
the OFF signal, the processing proceeds to S807. In other words,
when the manual feed sheet presence sensor 214 outputs the OFF
signal in S801, and still outputs the OFF signal after the
predetermined period of time T1 has elapsed, the processing
proceeds to S807.
[0063] In S807, the CPU 301 sets a normally detectable flag of the
manual feed size, which is a variable in the RAM 303, to OFF (the
normally detectable flag of the manual feed size=OFF), and the
processing returns to S801. The CPU 301 determines that the
detection of the sheet size by the sensors arranged on the manual
feed tray 210 cannot be normally carried out. In this state,
despite the fact that the manual feed sheet presence sensor 214
outputs the OFF signal, namely the sheet is not set on the manual
feed tray 210, at least one of the manual feed sheet length sensors
218 and 219 outputs the ON signal. In this case, the sensor
arranged on the manual feed tray 210 cannot normally detect the
size of the sheet. In this embodiment, when the sensor located on
the downstream side in the conveyance direction of the sheet does
not detect the presence of the sheet, and the sensor located on the
upstream side of the sensor, which does not detect the presence of
the sheet, in the conveyance direction detects the presence of the
sheet, the following operation is carried out. Specifically, the
CPU 301 determines that the size of the sheet cannot be determined
by the plurality of sensors arranged on the manual feed tray
210.
[0064] The reason for the processing of S804 in which the CPU 301
waits until the predetermined period of time T1 elapses is
described below. There is a conceivable state in which, in the
course of the setting of the sheet on the manual feed tray 210 by
the user, the manual feed sheet presence sensor 214 outputs the OFF
signal, and at least one of the manual feed sheet length sensors
218 and 219 outputs the ON signal. The transient state of the
detection result of the sensors generated in the course of the
setting of the sheet on the manual feed tray 210 cannot be
determined as the abnormality of the sensors. Therefore, in S804,
the CPU 301 waits until the predetermined period of time T1
elapses. In this embodiment, the predetermined period of time T1
is, for example, 3 seconds.
[0065] In S806, the CPU 301 sets the normally detectable flag of
the manual feed size, which is the variable in the RAM 303, to ON
(the normally detectable flag of the manual feed size=ON). This is
because the size of the sheet can be determined by the plurality of
sensors arranged on the manual feed tray 210 when the processing
proceeds to S806. In S808, the CPU 301 sets an alarm screen display
flag, which is the variable in the RAM 803, to OFF (alarm screen
display flag=OFF), and the processing returns to S801. The alarm
screen display flag is described later in a second embodiment of
the present invention.
[0066] In S801, when the CPU 301 determines that the manual feed
sheet presence sensor 214 outputs the ON signal, the processing
proceeds to S809. In S809, the CPU 301 determines whether or not
the manual feed sheet length sensor 219 outputs the ON signal. In
S809, when the CPU 301 determines that the manual feed sheet length
sensor 219 outputs the OFF signal, the processing proceeds to S806.
In this way, when the sensor located on the downstream side in the
conveyance direction of the sheet detects the presence of the
sheet, and the sensor located on the upstream side of the sensor,
which detects the presence of the sheet, in the conveyance
direction of the sheet does not detect the presence of the sheet,
the CPU 301 determines that the size detection for the sheet is
normal. Moreover, when all of the sensors arranged on the manual
feed tray 210 in the conveyance direction of the sheet detect the
presence of the sheet, the CPU 301 determines that the size
detection for the sheet is normal.
[0067] In S809, when the CPU 301 determines that the manual feed
sheet presence sensor 219 outputs the ON signal, the processing
proceeds to S810. In S810, the CPU 301 determines whether or not
the manual feed sheet length sensor 218 outputs the ON signal. When
the CPU 301 determines that the manual feed sheet length sensor 218
outputs the ON signal, the processing proceeds to S806. In S810,
when the CPU 301 determines that the manual feed sheet length
sensor 218 outputs the OFF signal, the processing proceeds to S811.
In this case, as described with reference to FIG. 3A, among the
respective sensors arranged on the manual feed tray 210, the manual
feed sheet presence sensor 214 and the manual feed sheet length
sensor 219 arranged on the both sides of the manual feed tray 210
in the conveyance direction output the ON signals. The manual feed
sheet length sensor 218 arranged on the center side of the manual
feed tray 210 in the conveyance direction outputs the OFF
signal.
[0068] In S811, by referring to the timer, the CPU 301 determines
whether or not a predetermined period of time T2 has elapsed. When
the CPU 301 determines that the predetermined period of time T2 has
not elapsed, the processing of S811 is repeated. In S811, when the
CPU 301 determines that the predetermined period of time T2 has
elapsed, the processing proceeds to S812. The CPU 301 again
determines whether or not the manual feed sheet length sensor 218
outputs the ON signal. In S812, when the CPU 301 determines that
the manual feed sheet length sensor 218 outputs the ON signal, the
processing proceeds to S806. When the CPU 301 determines that the
manual feed sheet length sensor 218 outputs the OFF signal, the
processing proceeds to S807. The predetermined period of time T2 in
S811 is 3 seconds, which is the same as the predetermined period of
time T1. The predetermined period of time T2 is set to a sufficient
period of time for resolving a deflection on a sheet A, even if the
deflection is generated when the sheet A is stacked on the manual
feed tray 210. FIG. 7 illustrates a state in which the deflection
is generated on the sheet A when the sheet A is stacked on the
manual feed tray 210, and a portion near the center of the sheet A
in the conveyance direction is temporality lifted upward from the
manual feed tray 210.
[0069] The processing of S809 to S812 are carried out in order to
detect the following state of the sheet on the manual feed tray
210. FIG. 7 is an enlarged view of a portion of the manual feed
tray 210 of the image forming apparatus 100 illustrated in FIG. 2.
As illustrated in FIG. 7, the portion near the center of the sheet
A set on the manual feed tray 210 may be in the lifted state due to
stiffness or the deflection (also referred to as "curl") of the
sheet. In the state illustrated in FIG. 7, the flag 214a blocks the
light in the photointerrupter 214b, and the manual feed sheet
presence sensor 214 is thus turned on. The flag 218a does not block
the light in the photointerrupter 218b, and thus the manual feed
sheet length sensor 218 outputs the OFF signal. Further, the flag
219a blocks the light in the photointerrupter 219b, and thus the
manual feed sheet length sensor 219 outputs the ON signal. In the
state illustrated in FIG. 7, the sheet size of the sheet A on the
manual feed tray 210 cannot be normally detected. Even if the sheet
itself is normally set on the manual feed tray 210, when the manual
feed sheet length sensor 218 is defective, and is always outputs
the OFF signal, the size of the sheet set on the manual feed tray
210 cannot be normally detected. Even in this state, a case may
occur in which the manual feed paper presence sensor 214 outputs
the ON signal, the manual feed sheet length sensor 218 outputs the
OFF signal, and the manual feed sheet length sensor 219 outputs the
ON signal. The control illustrated in FIG. 6 is carried out
independently of and in parallel with other control.
[0070] (Presence or Absence of Normal Detection of Sheet Size)
[0071] FIG. 8 is a flowchart for illustrating the processing of
carrying out display on the operation portion 330, which is based
on the flowchart of FIG. 5. In this processing, based on the result
of the determination as to whether or not the size detection for
the sheet can be normally carried out by using the sensors arranged
on the manual feed tray 210 in the processing illustrated in FIG.
6, the display is carried out on the operation portion 330. In this
embodiment, in place of the basic flowchart of FIG. 5, the
processing may also be carried out by following the flowchart of
FIG. 8. In S901, the CPU 301 determines whether or not the manual
feed sheet presence sensor 214 outputs the ON signal. When the CPU
301 determines that the manual feed sheet presence sensor 214
outputs the OFF signal, the processing of S901 is repeated. In
S901, when the CPU 301 determines that the manual feed sheet
presence sensor 214 outputs the ON signal, the CPU 301 determines
whether or not the normally detectable flag of the manual feed
size, which is the variable of the RAM 303, is set to ON in S902.
The normally detectable flag of the manual feed size holds the
value set by the processing of S806 or S807 of FIG. 6.
[0072] In S902, when the CPU 301 determines that the normally
detectable flag of the manual feed size is set to ON, the
processing proceeds to S903. The CPU 301 refers to the value of the
normally detectable flag of the manual feed size, and determines
that the size detection for the sheet can be normally carried out
by using the sensors arranged on the manual feed tray 210. The CPU
301 carries out the size detection for the sheet on the manual feed
tray 210 by the processing starting from S903. The processing from
S903 to S909 of FIG. 8 is the same as the processing from S702 to
S708 of the FIG. 5 described above, and description thereof is
omitted. When the CPU 301 normally carries out the size detection
for the sheet by using the sensors arranged on the manual feed tray
210, the CPU 301 displays the manual feed sheet size display screen
500 of FIG. 4A on the display portion 334 of the operation portion
330 in S909.
[0073] In S902, when the CPU 301 determines that the normally
detectable flag of the manual feed size is set to OFF, the CPU 301
determines that the size detection for the sheet cannot be normally
carried out by using the sensors arranged on the manual feed tray
210. Therefore, the CPU 301 displays the manual feed sheet size
designation screen 600 described with reference to FIG. 4B on the
display portion 334 of the operation portion 330 in S910. This
screen is used to prompt the user to designate the size of the
sheet instead of automatically determining the size of the sheet
when the size detection for the sheet cannot be normally carried
out by using the sensors arranged on the manual feed tray 210.
[0074] In this embodiment, the screen to be displayed on the
display portion 334 of the operation portion 330 is switched
between for a case in which the size detection for the sheet can be
normally carried out by using the sensors arranged on the manual
feed tray 210 and for the case in which the size detection cannot
be normally carried out. In other words, when the size detection
for the sheet can be normally carried out, the CPU 301 displays the
manual feed sheet size display screen 500 of FIG. 4A on the display
portion 334 by the processing of S909 of FIG. 8. When the size
detection for the sheet cannot be normally carried out, the CPU 301
displays the manual feed sheet size designation screen 600 of FIG.
4B on the display portion 334 by the processing of S910 of FIG. 8.
As a result, according to this embodiment, without spoiling the
usability, the image failure or the paper jam caused by the
erroneous detection of the sheet size on the manual feed tray 210
can be prevented.
[0075] As described above, according to the first embodiment, the
image failure or the paper jam caused by the erroneous detection
when the sheet size is detected by the manual feed tray can be
prevented.
Second embodiment
[0076] (Manual Feed Size Detection Alarm Screen)
[0077] Referring to FIG. 9 and FIG. 10, the second embodiment is
now described. FIG. 9 illustrates a screen for prompting the user
to check temporary placement and the like. This screen is displayed
when it is determined that the size detection for the sheet on the
manual feed tray 210 cannot be normally carried out in the
processing described with reference to FIG. 6. In this embodiment,
the following cases are assumed as the case in which the size
detection for the sheet cannot be normally carried out by the
sensors arranged on the manual feed tray 210. A first case is a
case in which at least one of the manual feed sheet length sensor
218 and the manual feed sheet length sensor 219 fails. A second
case is a case in which a sheet other than the sheet subjected to
the printing or an object (hereinafter referred to as "foreign
matter") is temporarily placed on the manual feed tray 210. The
temporary placement refers to placement of a sheet not to be
subjected to copying or printing or an object that changes the
state of the sensor arranged in the conveyance direction of the
sheet. FIG. 9 illustrates a manual feed size detection alarm screen
1000 which is a third screen, when assuming the second case.
Specifically, the temporary placement of a foreign matter on the
manual feed tray 210 is assumed, and a screen for prompting the
user to check the manual feed tray 210 is displayed. The user
removes the foreign matter on the manual feed tray 210, and the
sheet is set again. Then, the size detection for the sheet is again
carried out by the various sensors arranged on the manual feed tray
210. The user can depress the OK button 1001 to return the display
on the display portion 334 of the operation portion 330 from the
display of the manual feed size detection alarm screen 1000 to a
predetermined display screen.
[0078] (Display of Manual Feed Size Detection Alarm Screen)
[0079] FIG. 10 is a flowchart for illustrating processing for
carrying out the display of the manual feed size detection alarm
screen 1000. The processing from S1101 to S1110 of FIG. 10 is the
same as the processing from S901 to S910 of the FIG. 8 described
above, and description thereof is omitted. In S1102, when the CPU
301 determines that the normally detectable flag of the manual feed
size is set to OFF, the processing proceeds to S1111. The CPU 301
determines that the detection of the sheet size by the sensors
arranged on the manual feed tray 210 cannot be normally carried
out. In S1111, the CPU 301 determines whether or not the value of
the alarm screen display flag stored by the processing of S808 of
FIG. 6 is set to ON.
[0080] In S1111, when the CPU 301 determines that the alarm screen
display flag is set to OFF, the processing proceeds to S1112. The
case, in which the normally detectable flag of the manual feed size
is set to OFF and the alarm screen display flag is set to OFF,
corresponds to a state described below. In the state, the size
detection cannot be normally carried out for the first time after
the size detection has been normally carried out by using the
sensors arranged on the manual feed tray 210, and this state is a
first abnormality detection. In S1112, the CPU 301 displays the
manual feed size detection alarm screen 1000 described with
reference to FIG. 9 on the display portion 334 of the operation
portion 330. In S1113, the CPU 301 sets the alarm screen display
flag, which is the variable of the RAM 303, to ON, and the
processing proceeds to S1114. In the processing of S1113, the CPU
301 stores the fact that the manual size detection alarm screen
1000 is once displayed on the display portion 334. In S1114, the
CPU 301 determines whether or not the manual feed sheet presence
sensor 214 outputs the OFF signal. When the CPU 301 determines that
the manual feed sheet presence sensor 214 does not output the OFF
signal, the CPU 301 repeats the processing of S1114. In S1114, when
the CPU 301 determines that the manual feed sheet presence sensor
214 outputs the OFF signal, namely, the sheet has been removed from
the manual feed tray 210, the processing returns to S1101.
[0081] In S1111, when the CPU 301 determines that the alarm screen
display flag is set to ON, the CPU 301 determines that, after the
size detection could not normally be carried out, the manual feed
size detection alarm screen 1000 has once been displayed on the
operation portion 330. The CPU 301 does not display the manual feed
size detection alarm screen 1000 on the display portion 334, and
the processing proceeds to S1110. In this embodiment, when the CPU
301 determines that the size of the sheet cannot be normally
detected by using the sensors arranged on the manual feed tray 210,
the CPU 301 only once displays the manual size detection alarm
screen 1000 on the display portion 334.
[0082] Only when the alarm screen display flag is set to OFF by the
processing of S808 of FIG. 6, the CPU 301 carries out the following
processing. Specifically, after the CPU 301 determines that the
size detection can be normally carried out, or after the three
sensors arranged on the manual feed tray 210 can no longer detect
the sheet, when the CPU 301 determines that the size detection is
abnormal for the first time, the CPU 301 displays the manual feed
size detection alarm screen 1000 on the operation portion 330. As a
result, when a foreign matter is temporarily placed on the manual
feed tray 210, the CPU 301 appropriately prompts the user to check
the manual feed tray 210. Then, the size detection for the sheet
can be normally carried out. In a case in which at least one of the
manual feed sheet length sensor 218 and the manual feed sheet
length sensor 219 fails, the display of the manual feed size
detection alarm screen 1000 is not repeated. As a result, the
usability is prevented from being spoiled.
[0083] As described above, according to the second embodiment, the
image failure or the paper jam caused by the erroneous detection
when the sheet size is detected by the manual feed tray can be
prevented.
Third embodiment
[0084] (Selection of Screen)
[0085] Referring to FIG. 11 and FIG. 12, a third embodiment of the
present invention is now described. FIG. illustrates a screen
displayed on the display portion 334 when the sheet size is
determined to be indefinite after the size detection for the sheet
is carried out by the sensors arranged on the manual feed tray 210.
The screen of FIG. 11 is displayed when the CPU 301 determines that
the sheet size is indefinite. This screen functions as a selecting
unit configured to select, in advance, which of the manual feed
sheet size display screen 500 and the manual feed sheet size
designation screen 600 is to be displayed on the display portion
334 of the operation portion 330. A screen setting screen 1200 for
selecting, in advance, the screen displayed when the sheet size on
the manual feed tray 210 is indefinite includes two selection
buttons. Specifically, the screen setting screen 1200 includes a
selection button 1201 for selecting the manual feed sheet size
display screen 500 and a selection button 1202 for selecting the
manual feed sheet size designation screen 600. The user depresses
any one of the selection buttons 1201 and 1202, to thereby select
any one of the screens to be displayed in advance. After any one of
the selection buttons 1201 and 1202 is depressed, an OK button 1203
on the screen setting screen 1200 when the sheet size on the manual
feed tray 210 is indefinite is depressed. As a result, which of the
screens is to be displayed is determined. This screen setting
screen 1200 is displayed in response to the depression of the user
setting button 336 on the operation portion 330.
[0086] (Processing when Sheet Size on Manual Feed Tray is
Indefinite)
[0087] FIG. 12 is a flowchart for illustrating processing for
carrying out the display switching. This processing is carried out
by following the screen selected on the screen setting screen 1200
when the sheet size is determined to be indefinite in the size
detection for the sheet by the sensors arranged on the manual feed
tray 210. The processing from S1301 to S1308 of FIG. 12 is the same
as the processing from S901 to S908 of the FIG. 8 described above,
and description thereof is omitted. In S1308, the CPU 301 stores
information (such as "indefinite") representing that the sheet size
is indefinite as PapSize which is the variable in the RAM 303. The
CPU 301 determines which of the settings of the screen is made in
advance (S1310). The setting is made on the screen setting screen
1200 when the sheet size on the manual feed tray 210 is determined
to be indefinite, which is illustrated in FIG. 11.
[0088] The CPU 301 determines the content to be displayed on the
operation portion 330 according to the setting made in advance. The
setting is made on the screen setting screen 1200 when the sheet
size on the manual feed tray 210 is determined to be indefinite.
When the manual feed sheet size display screen 500 is set on the
screen setting screen 1200 (YES in S1310), the processing proceeds
to S1309.
[0089] When the manual feed sheet size designation screen 600 is
set on the screen setting screen 1200 (NO in S1310), the processing
proceeds to S1311. In S1309, the CPU 301 displays the manual feed
sheet size display screen 500 of FIG. 4A on the display portion 334
of the operation portion 330 based on the sheet size stored as the
PapSize, which is the variable in the RAM 303, and finishes the
processing. In S1311, the CPU 301 displays the manual feed sheet
size designation screen 600 of FIG. 4B on the display portion 334
of the operation portion 330, and finishes the processing.
Information of the sheet size designated on the manual feed sheet
size designation screen 600 of FIG. 4B is stored in an area, for
example, in the RAM 303, different from the area for the detection
results (S1303 to S1305) obtained by the sensors arranged on the
manual feed tray 210. The information of the designated sheet size
stored in the RAM 303 or the like is maintained until the sheet
size is designated on the manual feed sheet size designation screen
600 next time.
[0090] In the first and second embodiments, when the size of the
sheet on the manual feed tray 210 is indefinite, the manual feed
sheet size display screen 500 is displayed (S908 and S909 of FIGS.
8, and S1108 and S1109 of FIG. 10). In this embodiment, the setting
is made in advance on the screen setting screen 1200 of FIG. 11.
When the size of the sheet on the manual feed tray 210 is
determined to be indefinite, according to the made setting, any one
of the manual feed sheet size display screen 500 and the manual
feed sheet size designation screen 600 is displayed. As a result,
according to this embodiment, the usability can be increased.
[0091] As described above, according to the third embodiment, the
image failure or the paper jam caused by the erroneous detection
when the sheet size is detected by the manual feed tray can be
prevented.
[0092] While the present invention has been described with
reference to exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all such modifications and
equivalent structures and functions.
* * * * *