Image forming apparatus

Abstract

To provide an image forming apparatus capable of improving productivity.SOLUTION: An image forming apparatus includes: a housing; an image forming part; a door part; a first loading part disposed so as to be exposed outside the housing; a second loading part disposed inside the housing; a conveying part; an error detection part capable of detecting a first error that allows continuation of an image forming operation and a second error that makes the image forming operation impossible to continue; and a control part. The control part can execute a first recovery operation that controls the conveying part so as to discharge sheets to the first loading part and not to discharge sheets to the second loading part when the first error is detected, and a second recovery operation that controls the conveying part so as to discharge sheets to at least one of the first loading part and the second loading part when the second error is detected.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus that forms an image on a sheet. [Background technology]

[0002] Conventionally, an image forming system has been proposed that is composed of an upstream device, the device itself, and a downstream device (see Patent Document 1). Each of the upstream device, the device itself, and the downstream device has a transport path along which sheets are transported, and the transport paths of each device are arranged so that they are continuous. The device itself is provided with an escape tray that is connected to the transport path. If a jam occurs downstream of the escape tray in the sheet transport direction, sheets located upstream of the escape tray in the sheet transport direction are discharged to the escape tray. This reduces the number of sheets remaining in the transport path when a jam occurs, improving jam clearance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-69440 Summary of the Invention [Problem to be solved by the invention]

[0004] In an image forming system, it is desirable to provide escape trays at multiple locations in the system to reduce the number of sheets remaining in the system when a jam occurs. In addition to jams, there are also known errors that can be resolved without stopping the image forming operation.

[0005] If the escape tray is installed in a position that cannot be accessed during image formation operation, when the escape tray becomes fully loaded with sheets due to the error recovery operation described above, the image formation operation must be stopped, which causes a decrease in productivity.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of improving productivity. [Means for solving the problem]

[0007] The present invention relates to an image forming apparatus comprising: a housing; an image forming unit capable of executing an image forming operation for forming an image on a sheet; a door supported by the housing so as to be openable and closable; a first stacking unit arranged so as to be exposed to the outside of the housing and capable of stacking sheets; a second stacking unit arranged inside the housing and arranged so as not to be exposed to the outside of the housing when the door is closed relative to the housing, the second stacking unit capable of stacking sheets; a conveying unit that conveys sheets; an error detection unit capable of detecting a first error that allows the image forming operation to continue and a second error that makes it impossible to continue the image forming operation; and a control unit that controls the conveying unit. The control unit is capable of executing a first recovery operation to recover from the first error when the first error is detected by the error detection unit, the first recovery operation being a first recovery operation of controlling the conveying unit to discharge a sheet to the first stacking unit and not to discharge a sheet to the second stacking unit, and a second recovery operation to recover from the second error when the second error is detected by the error detection unit, the second recovery operation being a second recovery operation being a second recovery operation being a second recovery operation being a second recovery operation [Effects of the Invention]

[0008] According to the present invention, productivity can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a hardware block diagram of the image forming apparatus. [Figure 2] FIG. 1 is a cross-sectional view showing an image forming apparatus. [Figure 3]1A is a plan view showing the lift detection unit, FIG. 1B is a side view showing the lift detection unit when a normal sheet is conveyed, and FIG. 1C is a side view showing the lift detection unit when a lifted sheet is conveyed. [Figure 4] FIG. 4A is a plan view showing a size detection unit, and FIG. 4B is a plan view showing sheet sizes and image sizes. [Figure 5] 1A is a cross-sectional view showing a sheet conveyance state during execution of a simplex 18-sheet job, and FIG. 1B is a cross-sectional view showing a state after the simplex 18-sheet job has been completed. [Figure 6] 5A is a diagram showing sheet information managed by the job management unit at the timing shown in FIG. 5A, and FIG. 5B is a diagram showing sheet information managed by the job management unit at the timing shown in FIG. 5B. [Figure 7] 1A is a cross-sectional view showing a sheet conveyance state during execution of a double-sided 26-sheet job, and FIG. 1B is a cross-sectional view showing a state after the double-sided 26-sheet job has been completed. [Figure 8] 7A is a diagram showing sheet information managed by the job management unit at the timing shown in FIG. 7A, and FIG. 7B is a diagram showing sheet information managed by the job management unit at the timing shown in FIG. 7B. [Figure 9] 1A is a cross-sectional view showing the sheet transport state during execution of a double-sided 26-sheet job, and FIG. 1B is a cross-sectional view showing the state after the escape discharge process has been completed after a jam has been detected. [Figure 10] 9A is a diagram showing sheet information managed by the job management unit at the timing shown in FIG. 9A, and FIG. 9B is a diagram showing sheet information managed by the job management unit at the timing shown in FIG. 9B. [Figure 11] FIG. 2 is a front view showing the image forming apparatus. [Figure 12] 1A is an explanatory diagram showing the relationship between the position of a sheet and the escape discharge tray in the escape discharge process for recovering from a first error, and FIG. 1B is an explanatory diagram showing the relationship between the position of a sheet and the escape discharge tray in the escape discharge process for recovering from a second error. [Figure 13] 10 is a flowchart showing an escape discharge process. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Hardware configuration of image forming device] 1 is a hardware block diagram of an image forming apparatus 10 according to this embodiment. The image forming apparatus 10 has a controller unit 1000, which serves as a control unit and controls input and output of sensor signals and device information. The controller unit 1000 has a CPU (Central Processing Unit) 1001, a RAM (Random Access Memory) 1002, a ROM (Read Only Memory) 1003, and an HDD 1004.

[0011] A program describing processing contents is stored in the ROM 1003 or the HDD 1004. The CPU 1001 loads the program stored in the ROM 1003 or the HDD 1004 into the RAM 1002 and executes it. Furthermore, the CPU 1001 comprehensively controls each device connected to a system bus 1005. The RAM 1002 functions as the main memory and work memory of the CPU 1001. The ROM 1003 stores a boot program that is executed when the power is turned on, and the HDD 1004 stores the operating system and the main control program of the image forming apparatus 10.

[0012] The HDD 1004 is also used to temporarily or long-termly store large amounts of data. The Network 1006 is connected to a Local Area Network 1007 and is responsible for inputting and outputting data and device information to and from external devices. Programs can also be installed in the ROM 1003 or HDD 1004 via the Network 1006. The Device I / F 1008 is an interface with the Printer Engine 1009 and inputs and outputs signals for operating and referencing various motors, sensors, inkjet heads, and the like connected to the Printer Engine 1009. The Printer Engine 1009 is an inkjet output device that transports printing paper (sheets) under load control from the Controller Unit 1000 and controls the inkjet heads to output images onto the printing paper.

[0013] The job management unit 1020 accepts print jobs input via the network 1006, and manages and timings the transport of each sheet of paper, assigns print images to the sheets of paper, and sets the output tray (described later). The transport control unit 1011 controls the transport motors and sensors that feed each print sheet until it is ejected outside the machine. The head control unit 1010 controls the inkjet head provided in the printer engine 1009 via the device I / F 1008, and controls ink ejection for image formation in synchronization with the timing at which the paper reaches the ink head ejection position.

[0014] [Overall configuration of image forming device] 2 is a cross-sectional view showing an image forming apparatus 10 according to the present embodiment. As shown in FIG. 2, the image forming apparatus 10 is made up of six units: a paper feed section 100, a printing section 200, a fixing section 300, a cooling section 400, an inverting section 500, and a discharging section 600.

[0015] The paper feed unit 100 has feed cassettes 110, 111, and 112 on which various sheets (printing paper) used in printing processing are stacked, and a paper feed unit escape tray 113 on which discharged sheets are stacked. The paper feed unit 100 also has a paper feed unit escape tray sensor 120 that detects the presence or absence of a sheet on the paper feed unit escape tray 113. In this embodiment, the sheets include paper sheets and envelopes, plastic films such as overhead projector sheets (OHP), cloth, etc.

[0016] The printing unit 200 is a unit that prints a print image on a sheet. The printing unit 200 has an inkjet head 201, a print belt 202, a lift detection unit 210, and a size detection unit 220. The inkjet head 201, which serves as an image forming unit, ejects ink onto a sheet transported by the print belt 202 to form an image on the sheet. The lift detection unit 210 detects lifting of a sheet placed on the print belt 202. The size detection unit 220 detects the size of the sheet transported to the printing unit 200.

[0017] The fixing unit 300 is a unit responsible for fixing control to fix an image printed by the printing unit 200 onto a sheet, and fixes the printed image onto the sheet using multiple heater units (not shown). The fixing unit 300 has a double-sided inverting escape tray 301 on which discharged sheets are stacked. The double-sided inverting escape tray 301 is arranged to branch off from the double-sided conveying path 370. The fixing unit 300 also has a double-sided inverting escape tray sensor 320 that detects the presence or absence of a sheet on the double-sided inverting escape tray 301.

[0018] The cooling unit 400 is a unit that cools the sheet that has been heated in the fixing unit 300, and uses multiple fan units (not shown) to cool the sheet. The reversing unit 500 is a unit that can switch back and reverse the sheet to switch whether the printed side of the sheet is facing up or down. The reversing unit 500 has a reversing unit escape tray 501 on which discharged sheets are stacked, and a reversing unit escape tray sensor 520 that detects the presence or absence of a sheet on the reversing unit escape tray 501. The discharge unit 600 is a unit that controls the discharge of printed sheets, and has a discharge stacker tray 611 and an upper discharge tray 612.

[0019] Each of these six units includes a plurality of conveyance roller pairs that convey a sheet and a plurality of conveyance path sensors that detect the sheet being conveyed by the conveyance roller pairs. For example, the fixing unit 300 includes a conveyance roller pair 360 as a conveyance unit. Each conveyance roller pair, such as the conveyance roller pair 360, is controlled by a conveyance control unit 1011 of the controller unit 1000 in an escape discharge process, which will be described later. The paper feed unit 100 includes conveyance path sensors 141 and 142, and the printing unit 200 includes conveyance path sensors 231, 232, 241, and 242. The fixing unit 300 includes conveyance path sensors 331, 332, 341, 342, and 343, and the cooling unit 400 includes conveyance path sensors 431, 432, and 442. The reversing unit 500 includes conveyance path sensors 531 and 532, and the discharge unit 600 includes conveyance path sensors 631 and 632. The image forming apparatus 10 is configured to be able to determine whether a sheet is jammed during conveyance using these conveyance path sensors.

[0020] A print server 70 is connected to the image forming apparatus 10, and print jobs are sent from the print server 70 to the image forming apparatus 10. The print server 70 can check the status of the image forming apparatus 10, monitor print jobs, and perform maintenance control, and can comprehensively operate the various functions of the image forming apparatus 10.

[0021] [Sheet floating error] Next, using Figures 3(a) to 3(c), a description will be given of sheet floating errors detected by the floating detection unit 210. Figure 3(a) is a plan view showing the floating detection unit 210, Figure 3(b) is a side view showing the floating detection unit 210 when a normal sheet is conveyed, and Figure 3(c) is a side view showing the floating detection unit 210 when a floating sheet is conveyed.

[0022] The sheet floating error is an error that occurs when the sheet floats up to a position a predetermined distance above the print belt 202 upstream of the inkjet head 201 in the sheet conveyance direction. The sheet floating error can be detected by the floating detection unit 210.

[0023] As shown in FIGS. 2 and 3A, the lift detection unit 210 is composed of a light-emitting unit 210a and a light-receiving unit 210b, and is disposed upstream of the image formation position of the inkjet head 201 in the sheet conveyance direction CD. The light-emitting unit 210a is disposed on one side of the print belt 202 in the width direction W, which is perpendicular to the sheet conveyance direction CD, and the light-receiving unit 210b is disposed on the other side of the print belt 202. Light-receiving elements are arranged vertically inside the light-receiving unit 210b. When the light-receiving unit 210b receives a linear laser beam 213 emitted from the light-emitting unit 210a, the light-receiving unit 210b converts the laser beam 213 into an electrical signal and transmits it to an amplifier (not shown). The amplifier receives this electrical signal and can measure the extent to which the light-receiving elements arranged inside the light-receiving unit 210b are receiving or blocking light.

[0024] 3(b), when a normal sheet S is transported by the print belt 202, in the floating detection unit 210, the light receiving elements below the top surface position of the sheet are in a light-blocking state, and the light receiving elements above the top surface position of the sheet are in a light-receiving state. At this time, as a result of measurement by the amplifier, it is determined that the light-blocking position D1 by the sheet S is the top surface position of the sheet. The light-blocking position here refers to the boundary position between the light-blocked portion and the light-receiving portion in the light-receiving element array, and can also be referred to as the light-receiving position.

[0025] Furthermore, a threshold value DS serving as a detection threshold is set in advance in the amplifier, and if the measured light-blocking position is above the threshold value DS, the lift detection unit 210 is configured to send a signal to the outside to notify that a light-blocking object has been detected. The threshold value DS in this embodiment is a value that indicates that at least a portion of a light-blocking object located above the threshold value DS may come into contact with the inkjet head 201 (hereinafter referred to as head touch). The threshold value DS is set to an appropriate value taking into consideration factors such as the clearance between the print belt 202 and the inkjet head 201, variations in dimensional tolerances of each component, and variations in parallelism between the laser beam 213 and the print belt 202.

[0026] In this embodiment, when the lift detection unit 210 measures a light-blocking position above the threshold value DS due to an object lifted from the print belt 202, it transmits a detection signal to the controller unit 1000. In the example shown in FIG. 3(b), the light-blocking position D1 is below the threshold value DS, so no detection signal is transmitted to the controller unit 1000. Even if an object is present that has lifted from the print belt 202, unless the lift detection unit 210 detects a light-blocking position that exceeds the threshold value DS, there is no risk of the object touching the head. Therefore, no detection signal is transmitted from the lift detection unit 210 to the controller unit 1000, and normal sheet conveying and image forming operations are performed and continued.

[0027] In the example shown in FIGS. 3A and 3C, a folded portion Sf is formed at a corner of the sheet S. In this case, the folded portion Sf of the sheet S causes the light-blocking position at the light-receiving portion 210b of the lift detection unit 210 to be measured as light-blocking position D2. Because the light-blocking position D2 is above the threshold value DS, the lift detection unit 210 sends a detection signal to the controller unit 1000. In this embodiment, the controller unit 1000 recognizes a sheet lift error by sending the detection signal to the controller unit 1000. Thereafter, the controller unit 1000 issues a command to the CPU 1001 to stop ink ejection and executes escape discharge processing for the sheet S via the job management unit 1020. The escape discharge processing for the sheet S will be described later.

[0028] 3(a) and 3(c), the folded portion Sf of the sheet S is shown on the left side of the drawing, but regardless of where in the width direction W of the print belt 202 the lifting or deformation occurs, or even if the lifting or deformation occurs across the entire width direction W, if a light-blocking position exceeding the threshold value DS is measured as a result, the escape discharge process described above is performed. In other words, the lifting detection unit 210 detects the lifting of the sheet S. Furthermore, deformation of the sheet S is not limited to folds, but also includes various deformations such as curling and bending.

[0029] In this way, problems caused by head touch can be suppressed by detecting a sheet floating error using the floating detection unit 210 and executing the escape discharge process described below. One such problem is contamination of the inkjet head 201. As a specific example, it is conceivable that the sheet S collides with a print head ejecting Y (yellow) ink, causing the Y ink to adhere to the sheet S, and the sheet S then collides with the subsequent print head ejecting M (magenta) ink. In this case, the Y ink adheres to the print head ejecting the M ink. In this state, a mixture of the M ink and the Y ink is ejected onto the sheet S, which may result in normal image formation being impossible.

[0030] Another problem is damage to the inkjet head 201. If ink is ejected while the sheet S is in contact with the inkjet head 201, there is a risk that the ink ejection nozzles may be damaged, making it impossible to form a normal image.

[0031] Therefore, in order to prevent the various problems described above, it is necessary to detect a head touch (or a sheet floating error) in advance and then execute a process to prevent the head touch, or a process to create a state in which a problem does not occur even if a head touch occurs. In this embodiment, when the floating detection unit 210 detects a sheet floating error, the CPU 1001 issues a command to the head control unit 1010 to stop ink ejection and executes an escape discharge process for the sheet S via the job management unit 1020. This makes it possible to prevent the various problems described above.

[0032] [Size mismatch error] Next, using Figures 4(a) and (b), a description will be given of a size mismatch error detected by the size detection unit 220. Figure 4(a) is a plan view showing the size detection unit 220, and Figure 4(b) is a plan view showing the sheet size and image size.

[0033] The size mismatch error is an error that indicates that the size of the image formed by the inkjet head 201 does not match the size of the sheet detected by the size detection unit 220. The size mismatch error can be detected based on the detection result of the size detection unit 220.

[0034] 2 and 4(a), the size detection unit 220 is disposed upstream of the image forming position of the inkjet head 201 and the lift detection unit 210 in the sheet conveying direction CD. The size detection unit 220 is composed of image sensors 220a and 220b and an edge detection sensor 200c. The image sensor 220a is a line sensor capable of detecting one end SR of the sheet S in the width direction W, and the image sensor 220b is a line sensor capable of detecting the other end SL of the sheet S in the width direction W. The controller unit 1000 calculates the sheet width widS of the sheet S based on the detection results of the image sensors 220a and 220b.

[0035] The edge detection sensor 200c is disposed between the image sensors 220a and 220b in the width direction W, and detects the leading edge ST and trailing edge SB of the sheet S. The edge detection sensor 200c also detects the time from when the leading edge ST is detected to when the trailing edge SB is detected. The controller unit 1000 calculates the sheet length lenS, which is the length of the sheet S in the sheet conveying direction CD, based on the time and the conveying speed of the sheet S.

[0036] As shown in FIG. 4(b), the size of the image formed by the inkjet head 201 in the width direction W is defined as image width widImg, and the size of the image formed by the inkjet head 201 in the sheet conveyance direction CD is defined as image length lenImg. The size detection unit 220 measures the sheet width widS and sheet length lenS of the sheet S conveyed to the printing unit 200 and compares them with the image width widImg and image length lenImg. The role of the size detection unit 220 is to prevent problems that may occur due to a mismatch between the sheet size and the image size. One such problem is ink contamination inside the printing unit 200.

[0037] For example, consider the case where an image is formed on an A4-sized sheet S by the inkjet head 201. In this case, the default image size values ​​are widImg=205mm and lenImg=287mm. These default image size values ​​are set to be smaller than the international standard A4-sized sheet width of 210mm and length of 297mm by adding a margin width of 5mm and a margin length of 10mm.

[0038] At this time, assume that due to variations in cutting of the sheet, for example, a sheet S with a sheet width widS of 200 mm and a sheet length lenS of 280 mm is conveyed to the printing unit 200. Then, as shown in FIG. 4B, the sheet size becomes smaller than the image size, and ink protrudes from the sheet S, ejecting ink into an area Ipol (the area shaded in black in FIG. 4B). This causes the print belt 202 to be soiled with ink, and the ink adhering to the print belt 202 transfers to subsequent sheets. Furthermore, the ink adhering to the print belt 202 may damage the drive mechanism of the print belt 202 and contaminate the image sensor of the size detection unit 220.

[0039] Therefore, in order to prevent the above-mentioned various problems, it is necessary to detect a size mismatch error in advance and then execute processing to prevent contamination inside the print section 200. In this embodiment, the size detection section 220 detects a size mismatch error in advance and notifies the controller unit 1000. Thereafter, the CPU 1001 issues a command to the head control section 1010 to stop ink ejection and executes an escape discharge process for the sheet S via the job management section 1020, which will be described later.

[0040] In this embodiment, only cases where the sheet size is smaller than the image size are referred to as size mismatch errors, but cases where the sheet size is smaller than the image size may also be treated as size mismatch errors, and escape discharge processing or the like may be performed.

[0041] [Escape discharge process when a sheet floating error or size mismatch error is detected] Next, escape discharge processing when a sheet floating error or a size mismatch error is detected will be described using Figures 5(a) to 8(b). Figure 5(a) is a cross-sectional view showing the sheet transport state during execution of a simplex 18-sheet job, and Figure 5(b) is a cross-sectional view showing the state after the simplex 18-sheet job has been completed. The simplex 18-sheet job refers to a job in which single-sided printing is performed on 18 sheets. Figure 6(a) is a diagram showing sheet information managed by the job management unit 1020 at the timing shown in Figure 5(a), and Figure 6(b) is a diagram showing sheet information managed by the job management unit 1020 at the timing shown in Figure 5(b).

[0042] First, an example of escape ejection processing for a single-sided print job will be described. As shown in Fig. 5(a), image forming apparatus 10 conveys 18 sheets while executing a single-sided 18-sheet job. At this time, the first sheet S conveyed within image forming apparatus 10 is referred to as Sheet1, and the 18th sheet S is referred to as Sheet18. In other words, sheets S are referred to by "Sheet id" from Sheet1 to Sheet18.

[0043] In the state shown in Fig. 5(a), Sheet 1 has reached the discharge stacker tray 611. Also, in Fig. 5(a), a corner of Sheet 16 has been folded, and the sheet is in a state where it is about to be detected by the floating detection unit 210 as an abnormal sheet.

[0044] As shown in FIG. 6A, the sheet information managed by the job management unit 1020 includes a “Sheet ID” column 910, a “Discharge Tray” column 920, a “First Image” column 930, a “Second Image” column 940, and an “Image ID” column 950. The “Sheet ID” column 910 indicates the ID numbers of sheets Sheet1 through Sheet18. The “Discharge Tray” column 920 indicates the tray to which each sheet is discharged. The “First Image” column 930 indicates whether image formation has been performed on the first side of each sheet. The “Second Image” column 940 indicates whether image formation has been performed on the first side of each sheet. The “First Image” column 930 and the “Second Image” column 940 store information indicating “Completed” if image formation has started, or “Not yet” if image formation has not started. In addition, for single-sided jobs, image formation is not performed on the second side of the sheet, so the “Second Image” column 940 stores information indicating “None.” The "image id" column 950 holds the image id of the image formed on each sheet.

[0045] As shown in area 921 of Fig. 6(a), when a sheet floating error or a size mismatch error has not yet been detected, the discharge destination for all sheets from Sheet 1 to Sheet 18 is the discharge stacker tray 611. Also, as shown in area 951 of Fig. 6(a), the "image id" holds the same number as the "Sheet id."

[0046] When the sheet floating detection unit 210 detects a sheet floating error for Sheet16 shown in FIG. 5(a), the inkjet head 201 cancels ink discharge for Sheet16. Also, as shown in FIG. 6(b), the parameter 961 in the "ejection tray" column 920 for Sheet16 is changed to the reversing unit escape tray 501. Furthermore, image replacement processing is performed on Sheet17 and subsequent sheets, and the parameter 971 in the "image id" column 950 for Sheet17 is replaced with "16." Furthermore, the parameter 981 in the "image id" column 950 for Sheet18 is replaced with "17." Furthermore, Sheet19, whose parameter in the "image id" column 950 is set to "18," is additionally fed.

[0047] After that, the escape discharge process is executed based on the sheet information managed by the job management unit 1020 shown in Fig. 6(b), and as shown in Fig. 5(b), only Sheet 16 is discharged to the reverse unit escape tray 501. Then, Sheets 1 to 15 and 17 to 19 are discharged to the discharge stacker tray 611.

[0048] If the parameter 937 in the "Image first side" column 930 for Sheet 17 shown in FIG. 6(a) is "Completed" instead of "Not yet" at the time Sheet 16 is detected as abnormal paper, this means that the image replacement for Sheet 17 will not be completed in time. Therefore, Sheet 17 is also ejected to the reversing unit escape tray 501, and the parameter in the "image id" column 950 for Sheet 18 is changed to "16." Furthermore, Sheets 19 and 20, on which images with "image id" of "17" and "18" are printed, are additionally fed.

[0049] Next, an example of escape discharge processing in a double-sided printing job will be described. Fig. 7(a) is a cross-sectional view showing the sheet transport state during execution of a double-sided 26-sheet job, and Fig. 7(b) is a cross-sectional view showing the state after the double-sided 26-sheet job has been completed. Note that a double-sided 26-sheet job is a job in which double-sided printing is performed on 26 sheets. Fig. 8(a) is a diagram showing sheet information managed by the job management unit 1020 at the timing shown in Fig. 7(a), and Fig. 8(b) is a diagram showing sheet information managed by the job management unit 1020 at the timing shown in Fig. 7(b).

[0050] As shown in Fig. 7(a), the image forming apparatus 10 conveys 26 sheets while executing a double-sided 26-sheet job. At this time, the first sheet S conveyed within the image forming apparatus 10 is designated as Sheet1, and the 26th sheet S is designated as Sheet18. In other words, the sheets S are referred to by "Sheet id" from Sheet1 to Sheet26.

[0051] In the state shown in FIG. 7(a), Sheet 1 has reached the discharge stacker tray 611. Also in FIG. 7(a), a corner of Sheet 11 has been folded, and it is in a state just before being detected as abnormal paper by the floating detection unit 210. At this time, as shown in FIG. 8(a), in the sheet information managed by the job management unit 1020, the parameter 830 in the "first image" column 930 for Sheet 11 is "completed."

[0052] When the sheet floating detection unit 210 detects a sheet floating error in Sheet11 shown in FIG. 7(a), the inkjet head 201 cancels ink discharge for Sheet11. Also, as shown in FIG. 8(b), the parameter 811 in the "Discharge Tray" column 920 for Sheet11 is changed to the reversing unit escape tray 501. Furthermore, to maintain the order of the "image id," all sheets following Sheet11, for which the "Image First Side" column 930 is set to "Completed," are considered to be abnormal sheets.

[0053] First, ink ejection for the abnormal sheets is canceled. Next, escape ejection processing is performed for Sheets 12 to 25. As shown in FIG. 8(b), the parameter 812 in the "ejection tray" column 920 for Sheets 12 to 20 is changed to the paper feed unit escape tray 113. Furthermore, the parameter 813 in the "ejection tray" column 920 for Sheets 21 to 25 is changed to the reverse unit escape tray 501.

[0054] The parameters in the "Discharge Tray" column 920 are determined by the location of the sheet on the conveying path. The job management unit 1020 calculates all sheet positions on the conveying path based on the time elapsed since the sheet was fed. The correspondence between the conveying path and the escape discharge tray set by the escape discharge process will be described later.

[0055] Then, image replacement processing is performed on Sheet 26, and parameter 856 in "image id" column 950 for Sheet 26 is replaced with "11." Furthermore, as shown in area 857, Sheets 27 to 41, whose parameters in "image id" column 950 are "12" to "26," are additionally fed.

[0056] Although the escape discharge process when a sheet floating error is detected has been described with reference to FIGS. 5A to 8B, the same applies to the escape discharge process when a size mismatch error is detected.

[0057] [Escape ejection process when a jam is detected] Next, the escape discharge process when a sheet jam is detected will be described with reference to Figures 9(a) to 10(b). Figure 9(a) is a cross-sectional view showing the sheet transport state during execution of a double-sided 26-sheet job, and Figure 9(b) is a cross-sectional view showing the state after the escape discharge process has been completed after jam detection. Figure 10(a) is a diagram showing sheet information managed by the job management unit 1020 at the timing shown in Figure 9(a), and Figure 10(b) is a diagram showing sheet information managed by the job management unit 1020 at the timing shown in Figure 9(b).

[0058] 9A, conveyance path sensors 141, 142, 231, 232, 241, 242, 331, 332, 341, 342, 343, 431, 432, 442, 531, 532, 631, and 632 are provided on the conveyance path of the image forming apparatus 10 as sheet sensors. The CPU 1001 can detect the timing at which the sheet passes each conveyance path sensor based on the signal from each conveyance path sensor. The conveyance path sensors 141, 142, 231, 232, 241, 242, 331, 332, 341, 342, 343, 431, 432, 442, 531, 532, 631, and 632, the floating detection unit 210, and the size detection unit 220 constitute an error detection unit 700 that detects a first error and a second error, which will be described later.

[0059] 10A, in the sheet information managed by the job management unit 1020 before the jam is detected, the parameter in the "discharge tray" column 920 is the discharge stacker tray 611 for all sheets from Sheet 1 to Sheet 26. In the following, an example is given in which Sheet 14, which has been printed on one side, jams just before the conveyance path sensor 342.

[0060] If the time it takes for Sheet 14 to pass through conveying path sensor 343 and conveying path sensor 342 exceeds a certain time, CPU 1001 determines that Sheet 14 was not conveyed properly and detects a jam. The conveyance of Sheet 14, which caused the jam, is stopped. In this example, conveyance path 301a toward duplex reversing escape tray 301 is provided upstream in the sheet conveyance direction CD from the jam occurrence position. Therefore, even if Sheet 14 is stopped, Sheets 16 to 20 can be discharged to duplex reversing escape tray 301 via conveyance path 301a. Note that because Sheet 15 is located downstream of conveyance path 301a in the sheet conveyance direction CD, it cannot be discharged to duplex reversing escape tray 301, and sheet conveyance is stopped.

[0061] As shown in FIG. 10B, when a jam of Sheet 14 is detected, all sheets following Sheet 14 are deemed abnormal. As described above, sheet transport of Sheet 15 is stopped, and therefore the parameters in the "Discharge Tray" column 920 for Sheets 16 to 26 are changed, as shown in area 1212. Specifically, the parameters in the "Discharge Tray" column 920 for Sheets 16 to 20 are changed to the duplex reversing escape tray 301. The parameters in the "Discharge Tray" column 920 for Sheets 21 to 26 are changed to the reversing unit escape tray 501. The parameters in the "Discharge Tray" column 920 are determined based on the location of the sheet on the transport path. The job management unit 1020 calculates the positions of all sheets on the transport path based on the elapsed time since the sheet was fed. The correspondence between the transport path and the escape discharge tray set by the escape discharge process will be described later.

[0062] When all the sheets remaining in the image forming apparatus 10 and the sheets on the duplex reversing escape tray 301 are removed, the jam error is cleared and the print job is resumed. Whether or not all the sheets remaining in the image forming apparatus 10 have been removed is determined based on the detection results of each transport path sensor. Whether or not the sheets on the duplex reversing escape tray 301 have been removed is determined based on the detection result of the duplex reversing escape tray sensor 320.

[0063] [Access to each escape tray] Next, the accessibility of each escape tray will be described with reference to FIG. 11. FIG. 11 is a front view showing the image forming apparatus 10. As shown in FIG. 11, the paper feed unit 100 has an openable / closable paper feed unit door 150, which covers the transport path of the paper feed unit 100 when closed. The printing unit 200 has an openable / closable printing unit door 250, which covers the transport path of the printing unit 200 when closed. The fixing unit 300 has an openable / closable fixing unit door 350, which serves as a door and covers the transport path of the fixing unit 300 when closed.

[0064] The cooling unit 400 has an openable / closable cooling unit door 450, which covers the transport path of the cooling unit 400 when closed. The reversing unit 500 has an openable / closable reversing unit door 550, which covers the transport path of the reversing unit 500 when closed. The discharging unit 600 has an openable / closable discharging unit door 650, which covers the transport path of the discharging unit 600 when closed.

[0065] These doors are configured to be locked in a closed state by a locking mechanism (not shown). CPU 1001 controls the locking mechanism so that each door is locked while image forming apparatus 10 is performing an image forming operation. For example, fixing unit 300 has a locking mechanism 351 that locks fixing unit door 350, which is supported on housing 11 of image forming apparatus 10 so as to be openable and closable. Locking mechanism 351 locks fixing unit door 350 in a closed state relative to housing 11 while image forming operation is being performed. Note that each door is not limited to being made up of a single door member, and may be made up of multiple door members. For example, fixing unit door 350 may be made up of two door members that can be opened like a double door.

[0066] The sheet feed unit escape tray 113 is provided on the upper surface of the sheet feed unit 100, and a sheet discharged to the sheet feed unit escape tray 113 can be removed without opening the sheet feed unit door 150. The reversing unit escape tray 501 is provided on the upper surface of the reversing unit 500, and a sheet discharged to the reversing unit escape tray 501 can be removed without opening the reversing unit door 550. In other words, the sheet feed unit escape tray 113 and the reversing unit escape tray 501 are provided in an open space and are arranged so as to be exposed to the outside of the housing 11 of the image forming apparatus 10.

[0067] On the other hand, the duplex reversing escape tray 301 cannot be accessed unless the fixing unit door 350 is opened. That is, the duplex reversing escape tray 301 is disposed inside the housing 11. Therefore, the sheet discharged to the duplex reversing escape tray 301 is removed after the fixing unit door 350 is opened. In other words, the duplex reversing escape tray 301 is disposed so as not to be exposed to the outside of the housing 11 of the image forming apparatus 10. The fixing unit door 350 is locked by a locking mechanism 351 during image forming operation, so the duplex reversing escape tray 301 can be accessed only when the image forming operation is stopped due to a jam or the like or when no print job has been input. [Tray used in escape discharge process]

[0068] As described above, the job management unit 1020 determines the tray (referred to as an escape discharge tray) to which each sheet is discharged based on the position of the sheet within the image forming apparatus 10. The relationship between the position of the sheet and such an escape discharge tray will be explained using FIGS. 12(a) and 12(b). Note that, hereinafter, errors that allow the image forming operation to continue, such as a sheet floating error or a size mismatch error, will be referred to as a first error. On the other hand, errors that make it impossible to continue the image forming operation, such as a jam, will be referred to as a second error.

[0069] Fig. 12(a) is an explanatory diagram showing the relationship between the position of the sheet and the escape discharge tray in the escape discharge process for recovering from a first error, and Fig. 12(b) is an explanatory diagram showing the relationship between the position of the sheet and the escape discharge tray in the escape discharge process for recovering from a second error.

[0070] After the first error is detected, an escape discharge process is executed, thereby recovering from the first error without requiring recovery processing by the user, and the job is resumed. As shown in Fig. 12(a), a conveying path 9011 is a conveying path from a branch point P1 connected to the paper feed unit escape tray 113 to a branch point P2 connected to the reversing unit escape tray 501. The job management unit 1020 sets the reversing unit escape tray 501 as the escape discharge tray for abnormal paper related to the first error on this conveying path 9011.

[0071] The conveying path 9001 is a conveying path from a branch point P3 from the conveying path 9011 to a double-sided conveying path to a branch point P1. The job management unit 1020 sets the paper feed unit escape tray 113 as an escape paper discharge tray for abnormal paper related to the first error on this conveying path 9001.

[0072] Because the floating detection unit 210 and the size detection unit 220 are arranged on the conveying path 9011, an error sheet for which floating has been detected by the floating detection unit 210 is discharged to the inverting unit escape tray 501. Also, a sheet that has become abnormal because the image replacement was not completed in time, or a sheet following the error sheet that has become abnormal in order to maintain the order of the "image ID," are discharged to the inverting unit escape tray 501 or the paper feed unit escape tray 113. The duplex inverting escape tray 301 is not set as the escape discharge tray for abnormal sheets related to the first error.

[0073] On the other hand, after the second error is detected, recovery processing, such as manual sheet removal by the user, is required to remove sheets remaining in the image forming apparatus 10. After such recovery processing is performed, the job is resumed. The conveying path 9031 is a conveying path from branch point P3 to branch point P4 connected to the duplex inverting escape tray 301. As shown in FIG. 12B, the job management unit 1020 sets the duplex inverting escape tray 301 as the escape output tray for abnormal sheets related to the second error on this conveying path 9031. The job management unit 1020 then sets the paper feed unit escape tray 113 as the escape output tray for abnormal sheets related to the second error on the conveying path 9021 from branch point P4 to branch point P1. The job management unit 1020 also sets the inverting unit escape tray 501 as the escape output tray for abnormal sheets related to the second error on the conveying path 9011.

[0074] As described above, the sheet feed unit escape tray 113 and the reversing unit escape tray 501 can be accessed without going through the respective doors. On the other hand, the duplex reversing escape tray 301 can only be accessed after opening the fixing unit door 350, which is locked during image formation. Therefore, sheets on the duplex reversing escape tray 301 can only be removed when the image formation operation is stopped due to a jam or the like.

[0075] In this embodiment, in the case of a first error that allows the image forming operation to continue without stopping, the sheet feed escape tray 113 and the reversing unit escape tray 501 are set as escape discharge trays for each sheet. Therefore, as long as the user removes the sheets discharged to the sheet feed escape tray 113 and the reversing unit escape tray 501, the sheet feed escape tray 113 and the reversing unit escape tray 501 will not become full. Therefore, the job can be continued without stopping the image forming operation, improving productivity.

[0076] Furthermore, in the case of a second error that makes it impossible to continue image forming operations, it is possible to set an escape discharge tray for each sheet not only for the sheet feed unit escape tray 113 and the reversing unit escape tray 501 but also for the duplex reversing escape tray 301. This reduces the number of sheets remaining in the image forming apparatus 10 when a jam occurs, reduces the burden on the user of manual recovery processing, and improves usability.

[0077] In this embodiment, the double-sided reversing escape tray 301 is configured to be able to hold 60 sheets so that all sheets conveyed within the image forming apparatus 10 can be stacked. The double-sided reversing escape tray 301 is used only in the event of a second error such as a jam, and therefore full-load detection is not performed. This is because the user removes sheets from the double-sided reversing escape tray 301 when clearing a jam.

[0078] The sheet feeder escape tray 113 and the reversing unit escape tray 501 are configured to be able to hold 500 sheets because they are used as escape discharge trays for abnormal sheets due to the first error that occurs at a certain rate. In other words, the number of sheets that can be loaded on the sheet feeder escape tray 113 and the reversing unit escape tray 501 as the first stacking unit is greater than the number of sheets that can be loaded on the duplex reversing escape tray 301 as the second stacking unit.

[0079] After the sheet feed unit escape tray sensor 120 detects a sheet on the sheet feed unit escape tray 113, the CPU 1001 counts the sheets discharged to the sheet feed unit escape tray 113. Then, when the counted number of sheets exceeds the number of sheets that can be stacked on the sheet feed unit escape tray 113 (for example, 500 sheets), the CPU 1001 determines that the sheet feed unit escape tray 113 is fully loaded. When the sheet feed unit escape tray sensor 120 detects that a sheet has been removed from the sheet feed unit escape tray 113, the counted number of sheets is cleared and the determination that the sheet feed unit escape tray 113 is fully loaded is canceled.

[0080] Similarly, after the reversing unit escape tray sensor 520 detects a sheet on the reversing unit escape tray 501, the CPU 1001 counts the sheets discharged to the reversing unit escape tray 501. Then, when the counted number of sheets exceeds the number of sheets that can be loaded on the reversing unit escape tray 501 (for example, 500 sheets), the CPU 1001 determines that the reversing unit escape tray 501 is fully loaded. When the reversing unit escape tray sensor 520 detects that a sheet has been removed from the reversing unit escape tray 501, the counted number of sheets is cleared and the determination that the reversing unit escape tray 501 is fully loaded is canceled.

[0081] [Escape discharge processing flow] Next, the flow of the escape discharge process by the controller unit 1000 will be described in detail with reference to Fig. 13. The escape discharge process is a process in which, when a first error or a second error is detected, abnormal paper is discharged to an escape discharge tray that is set to recover from the error. Fig. 13 is a flowchart showing the escape discharge process. In this flowchart, the CPU 1001 and the job management unit 1020 make the judgment and switch the paper discharge tray (escape discharge tray), and the conveyance control of the sheet is performed by the conveyance control unit 1011. However, in the following, the controller unit 1000 will be the main controller of the flowchart.

[0082] 13, when a print job is started, the controller unit 1000 determines whether a size mismatch error has been detected by the size detection unit 220 (step S11). If a size mismatch error has not been detected by the size detection unit 220 (step S11: No), the process proceeds to step S13. If a size mismatch error has been detected (step S11: Yes), the controller unit 1000 ejects the error sheet for which the size mismatch error has been detected and any subsequent sheets for which image replacement cannot be made in time to the paper feed unit escape tray 113 or the reversing unit escape tray 501 (step S12).

[0083] In this embodiment, a size mismatch error is detected only once for the same sheet. Therefore, in the case of double-sided printing, the sheet S passes through the conveying path where the size detection unit 220 is located twice, but the size detection unit 220 does not detect the size of the sheet S immediately before forming an image on the second side of the sheet.

[0084] After steps S11 and S12, the controller unit 1000 determines whether or not a sheet floating error has been detected by the floating detection unit 210 (step S13). If a sheet floating error has not been detected (step S13: No), the process proceeds to step S17.

[0085] If a sheet floating error is detected (step S13: Yes), the controller unit 1000 ejects the error sheet for which the sheet floating error was detected and any subsequent sheets for which images cannot be replaced in time to the paper feed escape tray 113 or the reverse unit escape tray 501 (step S14). Next, the controller unit 1000 determines whether an image is formed on the first side of the error sheet (step S15: No). If an image is not formed on the first side of the error sheet (step S15: Yes), the controller unit 1000 proceeds to step S17. If an image is formed on the first side of the error sheet (step S15: Yes), the controller unit 1000 ejects all subsequent sheets following the error sheet with an image formed on its first side to the paper feed escape tray 113 or the reverse unit escape tray 501 in order to maintain the order of the "image id" (step S16).

[0086] For example, let us say that the error sheet in which a sheet floating error has been detected is the first sheet, and the sheet following the first sheet is the second sheet. At this time, let us say that the second sheet, duplex inverting escape tray 301, and sheet feeder escape tray 113 are lined up in this order in the sheet transport direction CD. In this case, the first sheet is discharged to the inverting unit escape tray 501. The second sheet is not discharged to the duplex inverting escape tray 301, but to the sheet feeder escape tray 113. In other words, even though the duplex inverting escape tray 301 is the discharge tray closest to the second sheet in the sheet transport direction CD, the second sheet is not discharged to the duplex inverting escape tray 301.

[0087] Next, the controller unit 1000 determines whether a jam has been detected by each transport path sensor (step S17). If a jam has been detected (step S17: Yes), and if there is a transport path 301a heading toward the double-sided reversing escape tray 301 upstream of the jam occurrence position in the sheet transport direction CD, the controller unit 1000 performs the following operation. That is, the controller unit 1000 discharges the sheet following the jammed sheet that caused the jam to the paper feed unit escape tray 113, the reversing unit escape tray 501, or the double-sided reversing escape tray 301 (step S18). Then, the escape discharge process ends.

[0088] If no jam is detected (step S17: No), the controller unit 1000 determines whether the sheet feed escape tray 113 or the reversing unit escape tray 501 is fully loaded (step S19). If it is determined that the sheet feed escape tray 113 or the reversing unit escape tray 501 is fully loaded (step S19: Yes), the job is terminated.

[0089] Furthermore, if it is determined that the sheet feed escape tray 113 or the reversing unit escape tray 501 is not fully loaded (step S19: No), the controller unit 1000 determines whether the job is complete (step S20). If it is determined that the job is not complete (step S20: No), the process returns to step S11. If it is determined that the job is complete (step S20: Yes), the flow ends.

[0090] As described above, in this embodiment, in the case of a first error such as a sheet floating error or a size mismatch error that allows image forming operation to continue without stopping, an escape discharge process is executed as a first recovery operation to recover from the first error. In this escape discharge process, the conveyance roller pairs are controlled so that sheets are discharged only to the sheet feed unit escape tray 113 and the reversing unit escape tray 501 that are accessible to the user during image forming operation, and sheets are not discharged to the duplex reversing escape tray 301. This allows the job to continue unless sheets are removed from the sheet feed unit escape tray 113 or the reversing unit escape tray 501 and the trays become full, thereby improving productivity.

[0091] On the other hand, in the case of a second error such as a jam that makes it impossible to continue the image forming operation, an escape discharge process is executed as a second recovery operation to recover from the second error. In this escape discharge process, in addition to the sheet feed unit escape tray 113 and the reversing unit escape tray 501, the sheet can also be discharged to the duplex reversing escape tray 301, which is accessible only when the image forming operation is stopped. In other words, each conveyance roller pair is controlled so that the sheet is discharged to at least one of the sheet feed unit escape tray 113, the reversing unit escape tray 501, and the duplex reversing escape tray 301. This reduces the number of sheets remaining in the image forming apparatus 10, reduces the burden on the user of manual recovery processes, and improves usability.

[0092] <Other embodiments> In this embodiment, the sheet feeder escape tray 113 and the reversing unit escape tray 501 are provided as the first stacking unit, but only one of them may be provided. The location of the escape discharge tray used in the escape discharge process executed to recover from the first error or the second error may be set arbitrarily. For example, instead of the double-sided reversing escape tray 301, an escape discharge tray may be provided in a position covered by the printing unit door 250 or a position covered by the cooling unit door 450, and sheets may be discharged to the escape discharge tray in the escape process executed to recover from the first error.

[0093] In addition, in each of the above-described embodiments, the image forming apparatus 10 is an inkjet type that forms an image on a sheet by ejecting ink liquid from nozzles, but the present invention is not limited to this. For example, the present invention can also be applied to an electrophotographic type image forming apparatus.

[0094] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions. [Explanation of symbols]

[0095] 10: Image forming apparatus / 11: Housing / 113: Paper feed escape tray (first stacking section) / 141, 142, 231, 232, 241, 242, 331, 332, 341, 342, 343, 431, 432, 442, 531, 532, 631, 632: Sheet sensor (conveying path sensor) / 201: Image forming section (inkjet head) / 210: Float detection section / 220: Size detection section / 301: Second stacking section (duplex reversing escape tray) / 350: Door section (fuser section door) / 351: Locking mechanism / 360: Conveying section (conveying roller pair) / 370: Duplex conveying path / 501: First stacking section (reversing section escape tray) / 700: Error detection section / 1000: Control section (controller unit)

Claims

1. The housing and an image forming unit capable of performing an image forming operation to form an image on a sheet; a door portion supported on the housing so as to be openable and closable; a first stacking section that is disposed so as to be exposed to the outside of the housing and that is capable of stacking sheets; a second stacking section that is disposed inside the housing and is not exposed to the outside of the housing when the door section is closed relative to the housing, and that is capable of stacking sheets; a conveying unit that conveys a sheet; an error detection unit capable of detecting a first error that allows the image forming operation to continue and a second error that prevents the image forming operation from continuing; a control unit that controls the transport unit, The control unit a first recovery operation that is executed to recover from the first error when the first error is detected by the error detection unit, the first recovery operation controlling the conveying unit to discharge a sheet to the first stacking unit and not to discharge a sheet to the second stacking unit; a second recovery operation that is executed to recover from the second error when the second error is detected by the error detection unit, the second recovery operation being a second recovery operation of controlling the conveying unit to discharge sheets to at least one of the first stacking unit and the second stacking unit; An image forming apparatus characterized by:

2. when the first error is detected by the error detection unit for a first sheet, in the first recovery operation, the control unit controls the conveying unit to discharge the first sheet and a second sheet following the first sheet to the first stacking unit, and not to discharge the first sheet and the second sheet to the second stacking unit.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. when the first error is detected by the error detection unit for the first sheet, if the second sheet, the second stacking unit, and the first stacking unit are arranged in this order in the sheet conveying direction in the first recovery operation, the second sheet is not discharged to the second stacking unit but is discharged to the first stacking unit.

3. The image forming apparatus according to claim 2, wherein the image forming apparatus is a recording medium.

4. the error detection unit is disposed upstream of an image forming position where the image forming unit forms an image on the sheet in a sheet conveyance direction, and includes a lift detection unit that detects lifting of the sheet; the control unit executes the first recovery operation when the lifting detection unit detects the lifting of the sheet as the first error.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

5. the error detection unit is disposed upstream of an image forming position where the image forming unit forms an image on a sheet in a sheet conveyance direction, and includes a size detection unit that detects a size of the sheet; the control unit executes the first recovery operation when a size mismatch is detected as the first error, in which the size of the image formed by the image forming unit does not match the size of the sheet detected by the size detection unit.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

6. the error detection unit includes a sheet sensor that detects a sheet on a conveyance path provided inside the housing, the control unit executes the second recovery operation when the sheet sensor detects a jam as the second error.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

7. a locking mechanism that locks the door in a closed state relative to the housing while the image forming operation is being performed; 6. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

8. The number of sheets that can be stacked in the first stacking section is greater than the number of sheets that can be stacked in the second stacking section.

6. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

9. a double-sided conveying path for conveying the sheet, on which the image has been formed on the first side in the image forming unit, back to the image forming unit; the second stacking unit is arranged to branch off from the double-sided conveying path, 6. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

Images