JP2023008372A - Image forming apparatus, control method, and program - Google Patents

Abstract

To provide an image forming apparatus that prevents generation of unnecessary downtime and is excellent in convenience.SOLUTION: A method for controlling an image forming apparatus includes: a step (S2) of detecting an actual size of a sheet conveyed to an image forming unit; and a step (S3) of determining whether or not the actual size is different from a specified size. The control method further includes: a step (S4) of determining whether or not an area for image formation performed by the image forming unit protrudes from the sheet having the actual size; and a step of controlling the operation of the image forming unit according to the determination that the actual size is different from the specified size. The controlling step includes: a step (S6) of stopping the operation of the image forming unit according to the determination that the image forming area protrudes from the sheet having the actual size; and a step (S5) of continuing the operation of the image forming unit according to the determination that the image forming area does not protrude from the sheet having the actual size.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to an image forming apparatus, control method and program.

Japanese Patent Application Laid-Open No. 2003-95482 (Patent Document 1) discloses an image forming method that detects the size of a fed sheet and stops the image forming operation in the case of a sheet size error where the detected size and the specified size do not match. An apparatus is disclosed.

JP-A-2003-95482

In the image forming apparatus disclosed in Patent Document 1, when the image forming operation is stopped due to a paper size error, the user needs to set the paper having the designated size and restart the image forming operation. However, there are users who judge that there is no problem as long as the image fits within the paper even if it is a paper size error. Such a user does not need downtime due to a paper size error, which reduces the convenience of the image forming apparatus.

The present disclosure has been made to solve the problems described above, and an object of the present disclosure is to provide an image forming apparatus, a control method, and a program that suppress the occurrence of unnecessary downtime and are excellent in convenience. It is to be.

According to one aspect, an image forming apparatus includes an image forming unit that forms an image according to a job, a detection unit that detects the actual size of paper conveyed to the image forming unit, and a designated size whose actual size is indicated by the job. and a first determination unit that determines whether or not it is different from . Further, the image forming apparatus includes a second determining unit that determines whether or not the image forming area by the image forming unit protrudes from the paper having the actual size; a control unit that executes a first process for controlling the operation of the image forming unit. In the first processing, when it is determined that the image forming area extends beyond the paper having the actual size, the operation of the image forming unit is stopped and it is determined that the image forming area does not extend beyond the paper having the actual size. continuing operation of the image forming station in response to the request.

According to another aspect, a control method is a control method for an image forming apparatus including an image forming section that forms an image according to a job. The control method includes the steps of detecting an actual size of paper conveyed to the image forming section, and determining whether the actual size is different from the specified size indicated by the job. Further, the control method includes the step of determining whether or not the image forming area by the image forming unit protrudes from the paper having the actual size; and controlling the operation. The step of controlling includes stopping the operation of the image forming unit in response to the determination that the image forming area extends beyond the paper having the actual size, and determining that the image forming area does not extend beyond the paper having the actual size. continuing operation of the imaging station responsive to the action.

According to yet another curve, the program causes the computer to perform the control method described above.

According to the present disclosure, it is possible to realize an image forming apparatus that suppresses the occurrence of unnecessary downtime and is excellent in convenience.

1 is a cross-sectional view schematically showing the overall configuration of an image forming apparatus according to an embodiment of the present disclosure; FIG. 3 is a diagram showing a configuration related to control of the image forming apparatus according to Embodiment 1; FIG. It is a figure which shows an example of the determination method of a 2nd determination part. 5 is a flowchart showing an example of the flow of control processing of the image forming apparatus according to Embodiment 1; FIG. 4 is a diagram showing an example of image formation for multiple pages; 10 is a flow chart showing an example of the flow of a control method for an image forming apparatus according to Embodiment 2; 10 is a flow chart showing the flow of a subroutine of step S17 in Embodiment 2. FIG. 10 is a flow chart showing the flow of a subroutine of step S17 in Embodiment 3. FIG. It is a figure which shows an example of a correction process. FIG. 14 is a flow chart showing the flow of a subroutine of step S17 in Embodiment 4. FIG. 4 is a cross-sectional view showing the state of the image forming apparatus when the trailing edge of the first page of paper has passed the timing sensor; FIG. It is a figure which shows the process content of step S41, S42. It is a figure which shows the process content of step S31. 14 is a flow chart showing the flow of a subroutine of step S17 in Embodiment 5. FIG. FIG. 20 is a flow chart showing the flow of a subroutine of step S17 in Embodiment 6. FIG.

An image inspection apparatus according to an embodiment according to the present disclosure will be described below with reference to the drawings. In the following description, identical parts and components are given identical reference numerals. Their names and functions are also the same. Therefore, detailed description of these will not be repeated. Note that the embodiments and modifications described below may be selectively combined as appropriate.

[Embodiment 1]
<Overall Configuration of Image Forming Apparatus>
FIG. 1 is a cross-sectional view schematically showing the overall configuration of an image forming apparatus according to an embodiment of the present disclosure. The image forming apparatus 1 shown in FIG. 1 forms an image on a sheet by a color tandem method. As shown in FIG. 1 , the image forming apparatus 1 includes a paper feeding section 10 , an image forming section 20 , a fixing device 30 and a conveying device 40 .

The paper feeding section 10 supplies paper to the image forming section 20 via the conveying device 40 . The paper feed unit 10 includes a paper feed cassette 11 and a paper feed roller 12 . The paper feed roller 12 supplies paper from the paper feed cassette 11 to the conveying device 40 . It should be noted that the image forming apparatus 1 may include a plurality of stages of the paper feeding units 10 .

The image forming section 20 includes photosensitive drums 21Y, 21M, 21C, and 21K, primary transfer rollers 22Y, 22M, 22C, and 22K, an intermediate transfer belt 23, and a secondary transfer roller 24.

The photoreceptor drums 21Y, 21M, 21C, and 21K are arranged at predetermined intervals along the extending direction of the intermediate transfer belt 23 under the intermediate transfer belt 23 . A charging device, an exposing device and a developing device (not shown) are arranged around each of the photosensitive drums 21Y, 21M, 21C and 21K. After the surface of the photosensitive drum 21Y is charged by the charging device, an electrostatic latent image is formed on the photosensitive drum 21Y by irradiating the photosensitive drum 21Y with light from the exposure device. Next, a developing device supplies yellow (Y) toner onto the photosensitive drum 21Y, thereby forming a yellow toner image on the photosensitive drum 21Y. By a similar method, a magenta (M) toner image, a cyan (C) toner image, and a black (K) toner image are formed on the photosensitive drums 21M, 21C, and 21K, respectively. That is, each of the photoreceptor drums 21Y, 21M, 21C, and 21K is one of image carriers that carry toner images.

The primary transfer rollers 22Y, 22M, 22C, and 22K face the photosensitive drums 21Y, 21M, 21C, and 21K, respectively, with the intermediate transfer belt 23 interposed therebetween. The primary transfer rollers 22Y, 22M, 22C and 22K transfer the toner images formed on the photosensitive drums 21Y, 21M, 21C and 21K onto the intermediate transfer belt 23, respectively.

The intermediate transfer belt 23 is an endless belt and is suspended by a plurality of rollers 25 . YMCK toner images are sequentially superimposed on the intermediate transfer belt 23 by primary transfer rollers 22Y, 22M, 22C, and 22K. As a result, a color image is formed. That is, the intermediate transfer belt 23 is one of image carriers that carry toner images. The intermediate transfer belt 23 rotates according to the rotation of the roller 25 and conveys the toner image to the position of the secondary transfer roller 24 .

The secondary transfer roller 24 transfers the toner image formed on the intermediate transfer belt 23 onto the paper conveyed by the conveying device 40 .

Fixing device 30 includes a fixing roller pair 32 . Fuser roller pair 32 includes a heating roller and a pressure roller. The fixing device 30 rotates the fixing roller pair 32 and causes the paper having the toner image transferred thereon to pass through the nip portion of the fixing roller pair 32 , thereby fixing the toner image on the paper.

The transport device 40 transports the paper supplied from the paper feed unit 10 along the transport path. As transport routes, a main route TR1, a reverse route TR2, and a sub route TR3 are provided. The main route TR1 is a route from the paper feeding unit 10 to the outside of the main body of the image forming apparatus 1 through the secondary transfer roller 24 and the fixing device 30 . The reverse path TR2 is a path branched from a branch point on the downstream side of the fixing device 30 in the main path TR1. The sub-path TR3 is a path that connects the final point of the reversing path TR2 to the confluence on the upstream side of the secondary transfer roller 24 on the main path TR1.

As shown in FIG. 1, the transport device 40 includes a timing roller 41, a paper discharge roller 42, a reversing roller 43, ADU (Auto Duplex Unit) transport rollers 44 and 45, and a refeed roller 46. include. Further, the transport device 40 includes a paper feed sensor 51 , a timing sensor 52 , a paper discharge sensor 53 , and ADU transport sensors 54 and 55 .

The timing roller 41 is arranged upstream of the secondary transfer roller 24 on the main path TR1. Timing roller 41 starts and stops conveying the paper so that the toner image is transferred to a specified position on the paper.

The paper ejection roller 42 is provided at the most downstream position of the main path TR<b>1 and ejects the paper outside the main body of the image forming apparatus 1 .

The reversing roller 43 is provided on the reversing route TR2, reverses the sheet on which double-sided printing is to be performed by switchback, and conveys the sheet to the sub-route TR3.

ADU transport rollers 44 and 45 transport the paper on which double-sided printing is to be performed along sub-path TR3.

The re-feeding roller 46 is provided at the most downstream re-feeding position of the sub-route TR3, and conveys the paper from the re-feeding position to the main route TR1.

The conveying device 40 includes a paper ejection guide (switching guide) not shown. The paper ejection guide switches the transport path of the paper that has passed through the fixing device 30 between the main path TR1 and the reversing path TR2, and guides the paper that has passed through the fixing device 30 to the paper ejection roller 42 or the reversing roller 43 .

The paper feed sensor 51 is provided on the most upstream side of the main path TR<b>1 and detects the paper fed from the paper feed section 10 . The timing sensor 52 is provided upstream of the timing roller 41 in the main path TR1, and detects the paper. The paper discharge sensor 53 is provided between the fixing device 30 and the paper discharge roller 42 on the main path TR1, and detects the paper. ADU transport sensors 54 and 55 detect paper on sub-path TR3. These sensors output an ON signal when paper is present and an OFF signal when paper is not present.

<Configuration for Control of Image Forming Apparatus>
FIG. 2 is a diagram showing a control configuration of the image forming apparatus according to the first embodiment. As shown in FIG. 2 , the image forming apparatus 1 includes an engine section 100 that controls image forming operations, and a system controller section 200 that controls the entire image forming apparatus 1 .

The engine section 100 includes a CPU (Central Processing Unit) 101 , a ROM (Read Only Memory) 102 , a RAM (Random Access Memory) 103 , a nonvolatile memory 104 and a drive motor 105 .

The ROM 102 stores a program 70 related to paper feeding, image formation and paper transport performed by the engine section 100, and the like.

Based on the program 70 stored in the ROM 102, the CPU 101 controls the operations related to image formation in an integrated manner while measuring the timing. The CPU 101 controls operations related to image formation in response to print requests from the system controller unit 200 .

A RAM 103 is a volatile memory and is a work area when the CPU 101 executes the program 70 .

The nonvolatile memory 104 serves as a data storage area when the CPU 101 executes the program 70 .

The drive motor 105 drives various rollers included in the paper feeding unit 10 , the image forming unit 20 , the fixing device 30 , and the conveying device 40 .

The system controller section 200 includes a CPU 201 and an operation section 202 . An operation unit 202 displays various information and accepts various operations. For example, the operation unit 202 accepts input of various information such as an image to be output and a paper size (hereinafter referred to as “specified size”), and notifies the CPU 201 of the accepted information.

CPU 201 accepts a job instructing image formation. The CPU 201 accepts a job according to various information input to the operation unit 202, for example. A job includes image data indicating an image to be output and condition data indicating conditions for image formation. The condition data indicates the specified size, the number of copies, and the like.

The CPU 201 executes analysis processing on image data included in the job, and outputs a print request to the CPU 101 of the engine section 100 according to the analysis result. The CPU 201 sequentially outputs print requests for each page. The print request includes information indicating the specified size and image forming area. The imaging area is the area to which toner is deposited. The information indicating the image forming area indicates the upper end position, the lower end position, the left end position and the right end position of the image forming area.

<Control related to paper size error>
The engine unit 100 includes a detection unit 61, a first determination unit 62, a second determination unit 63, and a control unit 64 as a configuration for performing control related to paper size errors. Detection unit 61 , first determination unit 62 , second determination unit 63 and control unit 64 are implemented by CPU 101 executing program 70 .

Detecting portion 61 detects the actual size of the paper conveyed to image forming portion 20 . The detection unit 61 counts the time from when the signal of the timing sensor 52 is switched from off to on until it returns to off, thereby detecting the length of the paper along the transport direction (FD (Feed Direction)) (hereinafter referred to as " FD length”) is calculated as the actual size. It should be noted that the detection unit 61 does not count the time during which the transport of the paper is stopped (that is, the time during which the paper feed roller 12 and the timing roller 41 are stopped).

The first determination unit 62 determines whether the actual size detected by the detection unit 61 is different from the specified size. The designated size is indicated by the job and included in the print request from the system controller unit 200. FIG. The first determination unit 62 calculates the difference between the actual size and the FD length specified from the specified size, and determines that the actual size is different from the specified size when the calculated difference is equal to or greater than the threshold. The threshold is determined in advance in consideration of detection accuracy by the detection unit 61 .

The second determination unit 63 determines whether or not the image forming area by the image forming unit 20 protrudes from the paper having the actual size.

FIG. 3 is a diagram illustrating an example of a determination method of the second determination unit; The second determination unit 63 identifies the top end position, bottom end position, left end position, and right end position of the image forming area R based on the information included in the print request from the system controller unit 200 . Further, in FIG. 3, the symbol "Pb" indicates a sheet of actual size.

The second determination unit 63 determines the length L1 from the upper end of the paper to the lower end of the image forming region R when the toner image corresponding to the image forming region R is transferred to the paper, and the FD length L2 detected as the actual size. compare. When the length L1 is longer than the FD length L2, the second determination portion 63 determines that the image forming area R protrudes from the paper Pb having the actual size.

In addition, when the FD length L2 matches the length of the long side of the standard-size paper, the second determination unit 63 determines the length of the paper transported to the image forming unit 20 in a direction orthogonal to the transport direction (CD (Cross Direction)). The length (referred to as “CD length”) may be estimated as the length of the short side of the standard paper. For example, when the detected FD length is 279 mm, the second determination unit 63 determines that the FD length matches the length of the long side of the standard paper "Letter", and the paper is conveyed to the image forming unit 20. Assume that the CD length of the paper is the same as the length of the short side of the standard paper "Letter", which is 210 mm.

When estimating the CD length L4 of the sheet conveyed to the image forming section 20, the second determination section 63 determines the distance from the left edge of the sheet to the right edge of the image forming area R when the toner image corresponding to the image forming area R is transferred onto the sheet. Compare the length L3 to the position with the CD length L4. When the length L3 is longer than the CD length L4, the second determination portion 63 determines that the image forming area R protrudes from the sheet Pb having the actual size.

Control unit 64 executes a first process for controlling the operation of image forming unit 20 in response to determination that the actual size is different from the specified size. The first process includes stopping the operation of the image forming section 20 in response to determination that the image forming area protrudes from the paper having the actual size. Furthermore, the first process includes continuing the operation of the image forming section 20 in response to the determination that the image forming area does not protrude from the paper having the actual size.

According to the first process, when it is determined that the image forming area does not protrude from the paper having the actual size, the operation of the image forming section 20 is continued to form an image on the paper. That is, no downtime occurs. As a result, the occurrence of unnecessary downtime is suppressed and the convenience is excellent.

On the other hand, when it is determined that the image forming area protrudes from the paper having the actual size, the operation of the image forming section 20 is stopped. Therefore, wasteful consumption of paper and toner is suppressed.

<Flow of image forming apparatus control method>
FIG. 4 is a flow chart showing an example of the flow of control processing of the image forming apparatus according to the first embodiment.

First, the CPU 101 determines whether or not the trailing edge of the sheet has passed the timing sensor 52 (step S1). Specifically, the CPU 101 determines whether or not the signal from the timing sensor 52 has switched from the ON state to the OFF state. When the signal from the timing sensor 52 switches from the ON state to the OFF state, the CPU 101 determines that the trailing edge of the sheet has passed the timing sensor 52 . If NO in step S1, the process returns to step S1.

If YES in step S1, the CPU 101 detects the actual size of the paper conveyed to the image forming section 20 based on the time during which the signal from the timing sensor 52 is on (step S2).

Next, CPU 101 determines whether or not the detected actual size is different from the specified size indicated by the job (step S3).

If the actual size is different from the designated size (YES in step S3), CPU 101 determines whether or not the image forming area by image forming section 20 protrudes from the paper having the actual size (step S4).

If NO in step S3 or NO in step S4, the CPU 101 continues the operation of the image forming section 20 (step S5). Specifically, the CPU 101 controls the image forming section 20 and the conveying device 40 to continue image formation in response to the print request.

If YES in step S4, the CPU 101 stops the operation of the image forming section 20 (step S6). It should be noted that in step S6, the CPU 101 also stops the operation of the peripheral devices of the image forming section 20 (for example, the conveying device 40).

[Embodiment 2]
In the image forming apparatus 1 according to the second embodiment, when a job instructing image formation of a plurality of pages is received, the first process similar to that of the first embodiment is executed for the target page (for example, the first page). A second process, which will be described later, is executed for pages subsequent to the target page (for example, pages after the second page).

FIG. 5 is a diagram showing an example of image formation for a plurality of pages. The imaging area can vary from page to page. In the example shown in FIG. 5, the image forming area R2 corresponding to the second page is larger than the image forming area R1 corresponding to the first page. Both the image forming areas R1 and R2 are accommodated on the paper Pa having the designated size. However, when a sheet Pb smaller than the specified size is set in the image forming apparatus 1, the image forming area may protrude from the sheet Pb. In the example shown in FIG. 5, the image forming area R1 fits within the sheet Pb, but the image forming area R2 protrudes from the sheet Pb.

Normally, sheets of the same size are set in the sheet feeding unit 10 of one stage. Therefore, images of multiple pages are likely to be formed on sheets of the same size. Therefore, when the actual size of the paper corresponding to the first page is detected by the detection unit 61, the image forming apparatus 1 can form the images of the subsequent pages from the second page on the paper having the actual size. to decide.

The second determination unit 63 of the image forming apparatus 1 according to the second embodiment determines whether or not the image forming area of the succeeding page protrudes from the paper having the actual size. The control unit 64 stops the operation of the image forming unit 20 when it is determined that the image forming area of the succeeding page protrudes from the paper having the actual size. The control unit 64 continues the operation of the image forming unit 20 in response to determining that the image forming area of the succeeding page does not protrude from the paper having the actual size.

FIG. 6 is a flow chart showing an example of the flow of the control method for the image forming apparatus according to the second embodiment. FIG. 6 shows a flowchart when a job instructing image formation of a plurality of pages is accepted.

First, the CPU 101 determines whether or not the trailing edge of the sheet corresponding to the first page has passed the timing sensor 52 (step S11). If NO in step S11, the process returns to step S11.

In the case of YES in step S11, CPU 101 detects the actual size of the paper conveyed to image forming section 20 based on the time during which the signal from timing sensor 52 is in the ON state (step S12).

Next, CPU 101 determines whether or not the detected actual size is different from the designated size indicated by the job (step S13).

If NO in step S13, the CPU 101 continues the operation of the image forming section 20 for all pages (step S14).

If the actual size is different from the designated size (YES in step S13), the CPU 101 determines whether or not the image forming area of the first page protrudes from the paper having the actual size (step S15).

If NO in step S15, the CPU 101 continues the operation of the image forming section 20 for the first page (step S16). After step S16, the CPU 101 executes control for subsequent pages (step S17).

If YES in step S15, CPU 101 stops the operation of image forming section 20 (step S18). In step S18, the CPU 101 also stops the operation of devices around the image forming section 20 (for example, the conveying device 40). After steps S14, S17 and S18, the process ends.

FIG. 7 is a flow chart showing the flow of the subroutine of step S17 in the second embodiment. The processing shown in FIG. 7 is the second processing performed on the subsequent page.

The CPU 101 substitutes 2 for the variable k (step S20). Next, the CPU 101 determines whether or not the kth page image forming area protrudes from the paper having the actual size (step S21). The image forming area for the kth page is indicated by information included in the print request for the kth page. CPU 101 executes step S21 using the actual size detected in step S12 (see FIG. 6). Therefore, if the CPU 101 receives a print request for page k, it can execute step S<b>21 before the trailing edge of the page k passes the timing sensor 52 .

If NO in step S21, the CPU 101 continues the operation of the image forming section 20 for page k (step S22).

Next, the CPU 101 determines whether or not a print request for page k+1 has been received from the system controller section 200 (step S23). If YES in step S23, the CPU 101 adds 1 to the variable k (step S24). After step S24, the process returns to step S21. If NO in step S23, the process ends.

If YES in step S21, CPU 101 stops the operation of image forming section 20 (step S25). In step S25, the CPU 101 also stops the operation of devices around the image forming section 20 (for example, the conveying device 40). After step S25, the process ends.

[Embodiment 3]
The image forming apparatus 1 according to the third embodiment executes processing according to the flowchart shown in FIG. 6, as in the second embodiment. However, the image forming apparatus 1 according to Embodiment 3 executes the subroutine shown in FIG. 8 instead of the subroutine shown in FIG. 7 in step S17.

FIG. 8 is a flow chart showing the flow of the subroutine of step S17 in the third embodiment. The processing shown in FIG. 8 is the second processing performed on the subsequent page.

The CPU 101 outputs to the CPU 201 an instruction to execute correction processing for correcting the image data included in the job according to the actual size for the succeeding page. As a result, the CPU 201 operating as a correction unit executes correction processing for correcting the image data included in the job according to the actual size for the succeeding page (step S30). Specifically, CPU 201 corrects the image data so that the image forming area is enlarged or reduced according to the ratio of the actual size to the designated size. For example, when the actual size is larger than the specified size, the CPU 201 enlarges the image forming area of the subsequent page. Conversely, if the actual size is smaller than the specified size, the CPU 201 reduces the image forming area of the succeeding page. The CPU 201 generates a print request corresponding to each subsequent page according to the corrected image data. The CPU 201 sequentially outputs the generated print requests to the CPU 101 .

Next, the CPU 101 continues the operation of the image forming section 20 for the subsequent page according to the print request generated based on the corrected image data (step S31).

FIG. 9 is a diagram illustrating an example of correction processing. In the example shown in FIG. 9, the image forming area R2 of the second page is reduced to an image forming area R2'. As a result, the corrected image forming area R2' fits on the paper Pb having the actual size.

[Embodiment 4]
A fourth embodiment is a modification of the third embodiment. A toner image corresponding to the second page may be formed on any one of the photosensitive drums 21Y, 21M, 21C, and 21K at the timing when the actual size of the paper corresponding to the first page is detected. The toner image already formed at the timing when the actual size is detected is based on the image data before the above correction processing is executed. Therefore, when transferred to a sheet of actual size, there is a possibility that the image may protrude from the sheet. Therefore, the control unit 64 of the image forming apparatus 1 according to the fourth embodiment controls the conveying device 40 so as to stop conveying the sheet corresponding to the second page as the second process for the succeeding page. and D. discarding the toner image corresponding to the second page carried on the carrier. Furthermore, the second process includes causing the CPU 201 to execute correction processing and restarting the operations of the image forming section 20 and the conveying device 40 according to the corrected image data.

The image forming apparatus 1 according to the fourth embodiment executes processing according to the flowchart shown in FIG. 6, as in the second and third embodiments. However, the image forming apparatus 1 according to Embodiment 4 executes the subroutine shown in FIG. 10 instead of the subroutine shown in FIG. 8 in step S17.

FIG. 10 is a flow chart showing the flow of the subroutine of step S17 in the fourth embodiment. The processing shown in FIG. 10 is the second processing executed for the succeeding page. The flowchart shown in FIG. 10 differs from the flowchart shown in FIG. 8 in that steps S40 to S42 are included.

In step S40, the CPU 101 determines whether the formation of the toner image of the second page on the image carrier has started.

If YES in step S40, CPU 101 controls conveying device 40 to stop conveying the sheet corresponding to page 2 (step S41). Next, the CPU 101 discards the toner image corresponding to the second page carried on the image carrier (step S42). Specifically, the CPU 101 controls the image forming section 20 so as not to secondarily transfer the toner image from the intermediate transfer belt 23 to the paper. The toner image on the intermediate transfer belt 23 is discarded by a cleaning blade (not shown).

After step S42 or if NO in step S40, steps S30 and S31 similar to those in the third embodiment are executed. When image formation for all pages is completed in step S31, the process ends.

FIG. 11 is a cross-sectional view showing the state of the image forming apparatus when the trailing edge of the first page of paper has passed the timing sensor. As shown in FIG. 11, when the trailing edge of the sheet P1 of the first page passes the timing sensor 52, toner images 80Y, 80M and 80C of the second page are formed on the photosensitive drums 21Y, 21M and 21C, respectively. It is Part of the toner images 80Y and 80M are transferred to the intermediate transfer belt 23. As shown in FIG. At this time, the sheet P2 of the second page is stopped by the sheet feeding roller 12. As shown in FIG. The toner images 80Y, 80M, and 80C are based on image data before correction processing is performed. Therefore, if the actual size of the paper P2 is smaller than the specified size, the toner images 80Y, 80M, and 80C may protrude from the paper P2 when transferred to the paper P2. According to the image forming apparatus 1 of Embodiment 4, YES is determined in step S40 in the state shown in FIG. As a result, steps S41 and S42 are executed.

FIG. 12 is a diagram showing the processing contents of steps S41 and S42. As shown in FIG. 12, the image forming apparatus 1 stops the rotation of the timing roller 41 and stops the conveying of the sheet P2 of the second page. That is, the leading edge of the paper P2 stops at the position of the timing roller 41 upstream of the secondary transfer roller 24 . The toner image 80 of the second page on the intermediate transfer belt 23 passes the position of the secondary transfer roller 24 without being transferred to the paper, and is discarded by a cleaning blade (not shown). When the discarding of the toner image 80 formed based on the image data before correction is completed, steps S30 and S31 are executed.

FIG. 13 is a diagram showing the processing contents of step S31. As shown in FIG. 13, the image forming apparatus 1 forms toner images 80Y, 80M, 80M, 80Y, 80M, 80M, 80M, 80M, 80M, 80Y, 80M, 80Y, 80M, 80Y, 80M, 80Y, 80M, 80Y, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, 80M, respectively on photoreceptor drums 21Y, 21M, 21C, 21K. Start forming 80C and 80K, respectively. After that, the rotation of the timing roller 41 is started at an appropriate timing, and the paper P2 is conveyed to the position of the secondary transfer roller 24 . As a result, a toner image based on the corrected image data is transferred onto the paper P2. As a result, even if the size of the paper P2 is smaller than the designated size, the image forming area of the second page fits within the paper P2.

[Embodiment 5]
The fifth embodiment is a combination of the second embodiment and the third embodiment. The image forming apparatus 1 according to the fifth embodiment executes processing according to the flowchart shown in FIG. 6, as in the second and third embodiments. However, the image forming apparatus 1 according to Embodiment 5 executes the subroutine shown in FIG. 14 in step S17.

FIG. 14 is a flow chart showing the flow of the subroutine of step S17 in the fifth embodiment. The processing shown in FIG. 14 is the second processing executed for the succeeding page. The flowchart shown in FIG. 14 includes steps S20 to S24 shown in FIG. Furthermore, the flowchart shown in FIG. 14 includes steps S30a and S31a.

The CPU 101 substitutes 2 for the variable k (step S20). Next, the CPU 101 determines whether or not the kth page image forming area protrudes from the paper having the actual size (step S21). If NO in step S21, the CPU 101 continues the operation of the image forming section 20 for page k (step S22).

If YES in step S21, the CPU 101 outputs to the CPU 201 an instruction to execute correction processing for correcting the image data included in the job according to the actual size for the k-th page. As a result, the CPU 201 operating as the correction unit executes correction processing for correcting the image data included in the job according to the actual size for the k-th page (step S30a). The CPU 201 generates a print request for page k according to the corrected image data, and outputs the generated print request to the CPU 101 .

Next, the CPU 101 continues the operation of the image forming section 20 for the k-th page according to the print request generated based on the corrected image data (step S31a).

After step S22 or after step S31a, the CPU 101 determines whether or not a print request for the k+1 page has been received from the system controller section 200 (step S23). If YES in step S23, the CPU 101 adds 1 to the variable k (step S24). After step S24, the process returns to step S21. If NO in step S23, the process ends.

[Embodiment 6]
The sixth embodiment is a combination of the fourth and fifth embodiments. The image forming apparatus 1 according to the sixth embodiment executes processing according to the flowchart shown in FIG. 6, as in the fourth and fifth embodiments. However, the image forming apparatus 1 according to Embodiment 6 executes the subroutine shown in FIG. 15 in step S17.

FIG. 15 is a flow chart showing the flow of the subroutine of step S17 in the sixth embodiment. The processing shown in FIG. 15 is the second processing executed for the succeeding page. The flowchart shown in FIG. 15 includes steps S20 to S24, S30a, and S31a shown in FIG. Furthermore, the flowchart shown in FIG. 15 includes steps S40a to S42a.

The CPU 101 substitutes 2 for the variable k (step S20). Next, the CPU 101 determines whether or not the kth page image forming area protrudes from the paper having the actual size (step S21). If NO in step S21, the CPU 101 continues the operation of the image forming section 20 for page k (step S22).

If YES in step S21, the CPU 101 determines whether or not the formation of the k-th page toner image on the image carrier has started (step S40a). If YES in step S40a, the CPU 101 controls the conveying device 40 to stop conveying the sheet corresponding to the k-th page (step S41a). Next, the CPU 101 discards the toner image corresponding to the k-th page carried on the image carrier (step S42a).

If NO in step S40a or after step S42a, the same steps S30a and S31a as in the fifth embodiment are executed.

After step S22 or after step S31a, the CPU 101 determines whether or not a print request for the k+1 page has been received from the system controller section 200 (step S23). If YES in step S23, the CPU 101 adds 1 to the variable k (step S24). After step S24, the process returns to step S21. If NO in step S23, the process ends.

[Modification]
In response to the fact that the actual size differs from the designated size, the control unit 64 adjusts the interval between the sheets supplied from the paper supply unit 10 (paper supply interval) to match the actual size for the pages following the first page. good too. This suppresses the occurrence of paper jams. Note that if the supply of the second page of paper is started at the timing when the actual size of the paper corresponding to the first page is detected, the control unit 64 sets the paper feed interval for the third and subsequent pages of paper. should be adjusted.

When the actual size is larger than the specified size, the CPU 101 may determine that the image forming area does not protrude from the paper having the actual size without using the determination method shown in FIG. That is, CPU 101 may continue the operation of image forming section 20 in response to the fact that the actual size is larger than the designated size.

In the above description, it is assumed that the first determination unit 62 and the second determination unit 63 are implemented by the CPU 101 . However, at least one of first determination unit 62 and second determination unit 63 may be implemented by CPU 201 of system controller unit 200 . In this case, the CPU 101 outputs information indicating the detected actual size to the CPU 201 . Using the information included in the job and the information indicating the actual size, the CPU 201 determines whether the actual size is different from the specified size and whether the image forming area protrudes from the paper having the actual size. good.

In Embodiments 3, 4, 5, and 6, the CPU 201 executes correction processing for correcting the image data included in the job for subsequent pages according to the actual size. Therefore, when the difference between the actual size and the specified size is large, the difference between the size of the image formed on the first page and the size of the images formed on the second and subsequent pages becomes large. The difference may give the user a sense of discomfort. Therefore, in Embodiments 3, 4, 5, and 6, CPU 101 stops the operation of image forming section 20 when the difference between the actual size and the specified size is greater than a predetermined standard. good. As a result, it is possible to prevent the above discomfort from being given to the user. Also in the other first and second embodiments, the CPU 101 may stop the operation of the image forming section 20 when the difference between the actual size and the designated size is greater than a predetermined reference. .

In addition, in the correction process described above, the CPU 201 changes the size of the image forming area so that the image forming area fits within the paper having the actual size and the ratio of the actual size to the designated size is closer to 1. Alternatively, the image data may be corrected. This also reduces the sense of discomfort.

Processing by the controller 64 may not be required by the user. Therefore, the operation unit 202 of the system controller unit 200 may accept an operation for switching between enabling and disabling the execution of the processes (including the first process and the second process) by the control unit 64 . The CPU 201 of the system controller unit 200 instructs the CPU 101 not to execute the control process in response to the operation to disable execution of the control process by the control unit 64 .

In Embodiments 5 and 6, Steps S30 and S31 of Embodiment 3 may be performed instead of Steps S30a and 31a. That is, when it is determined that the image forming area of any one of the subsequent pages after the second page protrudes from the paper of the actual size, the image data of all the pages after the page is adjusted to the actual size. can be corrected. In this case, the processing of steps S21 to S24 can be omitted for all pages after the current page.

The embodiments disclosed this time should be considered as examples and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

1 image forming apparatus 10 paper feeding section 11 paper feeding cassette 12 paper feeding roller 20 image forming section 21C, 21K, 21M and 21Y photosensitive drums 22C, 22M, 22Y and 22K primary transfer rollers 23 intermediate Transfer Belt 24 Secondary Transfer Roller 25 Roller 30 Fixing Device 32 Fixing Roller Pair 40 Conveying Device 41 Timing Roller 42 Discharge Roller 43 Reversing Roller 44, 45 ADU Conveying Roller 46 Refeeding Roller , 51 paper feed sensor, 52 timing sensor, 53 paper discharge sensor, 54, 55 ADU transport sensor, 61 detection section, 62 first determination section, 63 second determination section, 64 control section, 70 program, 80, 80C, 80K , 80M, 80Y toner image, 100 engine section, 101, 201 CPU, 102 ROM, 103 RAM, 104 non-volatile memory, 105 drive motor, 200 system controller section, 202 operation section, P1, P2, Pa, Pb paper, R , R1, R2 image forming area, TR1 main path, TR2 reverse path, TR3 sub path.

Claims (13)

An image forming apparatus,
an image forming unit that forms an image according to a job;
a detection unit that detects an actual size of a sheet conveyed to the image forming unit;
a first determination unit that determines whether the actual size is different from the specified size indicated by the job;
a second determination unit that determines whether an image forming area by the image forming unit protrudes from the paper having the actual size;
a control unit that executes a first process for controlling the operation of the image forming unit in response to determining that the actual size is different from the specified size;
The first processing is
stopping the operation of the image forming unit in response to determining that the image forming area protrudes from the paper having the actual size;
continuing the operation of the image forming unit in response to determining that the image forming area does not protrude from the paper having the actual size. The job instructs image formation of a plurality of pages,
The control unit executes the first process for a target page of the plurality of pages,
The image forming apparatus further includes a correction unit that executes correction processing for correcting image data included in the job according to the actual size for pages subsequent to the target page,
2. The image forming apparatus according to claim 1, wherein the control section operates the image forming section according to the image data corrected by the correction section for the succeeding page. 3. The image forming apparatus according to claim 2, wherein said correction section executes said correction processing in response to determining that said image forming area of said succeeding page protrudes from said sheet having said actual size. The job instructs image formation of a plurality of pages,
The image forming unit
an image carrier on which a toner image corresponding to the job is formed;
a transfer device that transfers the toner image from the image carrier to the paper,
The image forming apparatus further includes a transport device that transports the paper to the transfer device,
The control unit
executing the first process for a target page of the plurality of pages;
performing a second process on a subsequent page of the target page;
The image forming apparatus further includes a correction unit that executes correction processing for correcting image data included in the job according to the actual size,
The second processing is
controlling the conveying device to stop conveying the sheet corresponding to the succeeding page;
discarding the toner image corresponding to the succeeding page carried on the image carrier;
causing the correction unit to perform the correction process on the subsequent page;
2. The image forming apparatus according to claim 1, further comprising: restarting operations of said image forming section and said conveying device according to said corrected image data. 5. The image forming apparatus according to claim 4, wherein said control section executes said second process in response to determining that said image forming area of said succeeding page protrudes from said sheet having said actual size. The job instructs image formation of a plurality of pages,
The control unit
executing the first process for a target page of the plurality of pages;
performing a second process on a subsequent page of the target page;
The second processing is
stopping the operation of the image forming unit in response to determining that the image forming area of the succeeding page protrudes from the paper having the actual size;
2. The image according to claim 1, further comprising continuing the operation of the image forming unit in response to determining that the image forming area of the succeeding page does not protrude from the paper having the actual size. forming device. The correction processing is performed so that the image forming area fits within the paper having the actual size and the size of the image forming area is changed at a ratio closer to 1 than the ratio of the actual size to the designated size. 6. The image forming apparatus according to claim 2, further comprising a process of correcting said image data. The image forming apparatus further includes a paper feeding unit that supplies paper to the image forming unit,
The image forming apparatus according to any one of claims 2 to 7, wherein the controller adjusts an interval between sheets supplied from the paper feeder for the succeeding page according to the actual size. 9. The image forming apparatus according to any one of claims 1 to 8, wherein said control section continues the operation of said image forming section in response to said actual size being larger than said designated size. 9. The control unit according to any one of claims 1 to 8, wherein the control unit stops the operation of the image forming unit when a difference between the actual size and the specified size is larger than a reference. Image forming device. The image forming apparatus according to any one of claims 1 to 10, further comprising an operation unit that accepts an operation for switching between enabling and disabling execution of the first process by the control unit. A control method for an image forming apparatus including an image forming unit that forms an image according to a job, comprising:
a step of detecting an actual size of paper conveyed to the image forming unit;
determining whether the actual size is different from the specified size indicated by the job;
determining whether or not the image forming area by the image forming unit protrudes from the paper having the actual size;
controlling the operation of the image forming unit in response to determining that the actual size is different from the specified size;
The controlling step includes:
stopping the operation of the image forming unit in response to determining that the image forming area protrudes from the paper having the actual size;
and continuing the operation of the image forming unit in response to determining that the image forming area does not protrude from the paper having the actual size. A program that causes a computer to execute the control method according to claim 12.

Images