Image forming apparatus, control program, and control method

Abstract

To provide an image forming apparatus that can perform printing by using a sheet width size narrower than the dedicated width of a fixing roller.SOLUTION: An image forming apparatus comprises: a fixing device that includes a fixing roller having a dedicated width (Wex); and a counter that counts the number of sheets passing through the fixing device for every sheet width size. The image forming apparatus further comprises: a first determination unit (S5) that refers to the counter and determines if there is a sheet width size in which the number of times of printing has reached a threshold; a first print job execution unit (S7) that executes a print job when there is no sheet width size in which the number of times of printing has reached the threshold; a second determination unit (S15) that, when there is the sheet width size in which the number of times of printing has reached the threshold, determines whether the sheet width size is larger than the sheet width size in which the number of times of printing has reached the threshold; and a second print job execution unit (S7) that, when the sheet width size is determined not to be larger than the sheet width size in which the number of times of printing has reached the threshold, executes a print job on a sheet having the smaller sheet width size.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present disclosure relates to an image forming apparatus, a control program, and a control method, and more particularly to an image forming apparatus, a control program, and a control method for thermally fixing a toner image formed on a recording medium using a fixing roller and a pressure roller, for example. [Background technology]

[0002] In order to reduce streaks in paper caused by scratches on the surface of the fixing roller due to the side edges of the paper (paper edges), it is known to prohibit image formation (and display a message) when a paper width size narrower than the dedicated width size of the fixing roller is used, and to allow the user to select either prohibition or permission when a paper width size of the same size or wider is used (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-006486 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of Patent Document 1, printing is prohibited when using a paper width narrower than the dedicated width of the fixing unit, so if you need to print quickly, you must replace the fixing unit with one that has a dedicated width equal to the paper width. At this time, it is dangerous to replace the fixing unit until the temperature of the fixing unit has dropped sufficiently (there is a risk of burns), so you must wait until it cools down.

[0005] Therefore, a primary object of the present disclosure is to provide a novel image forming apparatus, a control program, and a control method.

[0006] Another object of the present disclosure is to provide an image forming apparatus, a control program, and a control method that allow printing using a paper width size narrower than the dedicated width size of the fixing rotor. [Means for solving the problem]

[0007] The first embodiment is an image forming apparatus equipped with a fixing device including a fixing rotor having a dedicated width and a pressure rotor that abuts against the outer peripheral surface of the fixing rotor to form a fixing nip portion between the fixing rotor and the image forming apparatus, and is equipped with a counter that counts the number of sheets of paper that have passed through the fixing device for each paper width size, a first judgment unit that refers to the counter to determine whether there is a paper width size for which the number of prints has reached a threshold, a first print job execution unit that executes a print job when the first judgment unit does not determine that there is a paper width size for which the number of prints has reached the threshold, a second judgment unit that determines whether the paper width size is larger than the paper width size for which the number of prints has reached the threshold when the first judgment unit determines that there is a paper width size for which the number of prints has reached the threshold, and a second print job execution unit that executes a print job for paper having the paper width size when the second judgment unit determines that the paper width size is not larger than the paper width size for which the number of prints has reached the threshold.

[0008] In the first embodiment, an image forming apparatus (10: reference symbols are used to illustrate corresponding parts in the embodiment but are not intended to be limiting; the same applies below) includes a fixing device (54) including a fixing roller (56) having a dedicated width (Wex). A counter (98e) counts the number of sheets of paper that have passed through the fixing device (54) for each paper width size (A3, B4, A4, A4R, B5, B5R, etc.). For example, by referring to the count value of the counter and a preset threshold, a first determination unit (70, S5) determines whether there is a paper width size for which the number of times of printing has reached the threshold. When the first determination unit does not determine that there is a paper width size for which the number of times of printing has reached the threshold, a first print job execution unit (70, S7) executes a print job. Therefore, this first print job execution unit executes a print job even for paper having a paper width size narrower than the dedicated width of the fixing roller. Conversely, when the first judgment unit judges that there is a paper width size for which the number of times printed has reached the threshold, a second judgment unit (70, S15) judges whether the paper width size in question is larger than the paper width size for which the number of times printed has reached the threshold. Then, when the second judgment unit judges that the paper width size in question is not larger than the paper width size for which the number of times printed has reached the threshold, a second print job execution unit (70, S7) executes a print job for paper having that smaller paper width size.

[0009] According to the first embodiment, a print job is executed even for paper having a paper width size narrower than the dedicated width of the fixing roller, and further, a print job is executed even when the paper width size is not larger than the paper width size for which the number of prints has reached a threshold value, thereby providing an image forming device that is convenient for the user.

[0010] The second embodiment is an image forming apparatus subordinate to the first embodiment, and further includes a first message screen display unit that displays a first message screen asking a user to confirm whether to allow printing even if there is a possibility of printing defects due to scratches on the fixing rotor when the first judgment unit determines that there is a paper width size for which the number of prints has reached a threshold value, and a third print job execution unit that executes a print job when the user allows printing.

[0011] In the second embodiment, the first message screen display unit (70, S17) displays the first message screen (FIG. 5, 86) to ask the user to confirm whether to permit printing even if there is a possibility of print defects (e.g., streaks) caused by scratches on the fixing roller. The first message screen displays a button (88y) for instructing the user to permit printing, together with a message (87) such as "Streaks may appear in the image. Do you permit printing?". When the user operates the button (88y), the second print job execution unit (70, S7) executes the print job.

[0012] According to the second embodiment, when printing defects are acceptable, for example, in the case of urgent printing or test printing, the print job can be executed without replacing the fixing device if the user gives permission.

[0013] A third embodiment is an image forming apparatus subordinate to the second embodiment, and further includes a replacement recommendation message screen display unit that displays a replacement recommendation message screen recommending replacement of the fixing device to the user when the user does not permit printing on the first message screen.

[0014] In the third embodiment, the replacement recommendation message screen display unit (70, S21) displays a replacement recommendation message screen (FIG. 7(A), 86 and / or FIG. 7(B), 86), so that the user can replace the fixing device in accordance with the display.

[0015] According to the third embodiment, since the replacement recommendation message screen is displayed, the user can execute a print job after replacing the fixing device.

[0016] The fourth embodiment is an image forming apparatus dependent on the first embodiment, in which a counter is provided in the fixing device, and a threshold value is set in the fixing device.

[0017] A fifth embodiment is a control program for an image forming device having a fixing device including a fixing rotor having a dedicated width and a pressure rotor that abuts against the outer peripheral surface of the fixing rotor to form a fixing nip portion between the fixing rotor and the fixing rotor, the control program causing a computer of the image forming device to function as a counter that counts the number of sheets of paper that have passed through the fixing device for each paper width size, a first judgment unit that refers to the counter to determine whether there is a paper width size for which the number of prints has reached a threshold value, a first print job execution unit that executes a print job when the first judgment unit does not determine that there is a paper width size for which the number of prints has reached the threshold value, a second judgment unit that determines whether the paper width size is larger than the paper width size for which the number of prints has reached the threshold value when the first judgment unit determines that there is a paper width size for which the number of prints has reached the threshold value, and a second print job execution unit that executes a print job for paper having the smaller paper width size when the second judgment unit determines that the paper width size is not larger than the paper width size for which the number of prints has reached the threshold value.

[0018] A sixth embodiment is a control method for an image forming device equipped with a fixing device including a fixing rotor having a dedicated width and a pressure rotor that abuts against the outer peripheral surface of the fixing rotor to form a fixing nip portion between the fixing rotor and the fixing rotor, in which the number of sheets of paper that have passed through the fixing device is counted for each paper width size, and the counted value is referred to to determine whether there is a paper width size for which the number of prints has reached a threshold value, and if it is determined that there is a paper width size for which the number of prints has reached the threshold value, a print job is executed, and if it is determined that there is a paper width size for which the number of prints has reached the threshold value, it is determined whether the paper width size is larger than the paper width size for which the number of prints has reached the threshold value, and if it is determined that the paper width size is not larger than the paper width size for which the number of prints has reached the threshold value, a print job is executed for paper having that paper width size.

[0019] The fifth and sixth embodiments are also expected to provide the same effects as the first embodiment. Effect of the Invention

[0020] According to the present disclosure, a print job is executed even for paper with a paper width size narrower than the dedicated width of the fixing roller, and further, a print job is executed even when the paper width size is not larger than the paper width size for which the number of prints has reached a threshold value, thereby providing an image forming device that is convenient for the user.

[0021] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of the embodiments taken in conjunction with the drawings. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of an image forming apparatus according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a block diagram showing an example of the electrical configuration of the image forming apparatus of FIG. [Diagram 3] FIG. 3 is a schematic diagram showing an example of the fixing device of this embodiment. [Figure 4] FIG. 4 is a diagram showing the problems caused by a fixing roller having a dedicated width Wex. [Diagram 5] FIG. 5 is an illustrative view showing an example of control of the fixing device according to the embodiment of the present disclosure. [Figure 6] FIG. 6 is an illustrative view showing an example of a message screen of the message 1 used in the embodiment. [Figure 7] FIG. 7 is an illustrative view showing one example of a message screen of message 2 and message 3 used in the embodiment. [Figure 8] FIG. 8 is a diagrammatic view showing possible situations where it would be appropriate to allow printing with a fuser roller having flaws in accordance with this embodiment. [Figure 9] FIG. 9 is an illustrative view showing an example of a memory map of the memory shown in FIG. 2. As shown in FIG. [Figure 10] FIG. 10 is a flow chart showing an example of the operation of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] With reference to FIG. 1, an image forming apparatus 10 according to a first embodiment of the present disclosure is a so-called multifunction peripheral (MFP) that forms a multicolor or monochrome image on paper by an electrophotographic method.

[0024] 1 is a view seen from the front side of image forming apparatus 10. That is, in Fig. 1, the up-down direction corresponds to the up-down direction of image forming apparatus 10, and the left-right direction corresponds to the left-right direction of image forming apparatus 10. The front side of the paper surface of Fig. 1 corresponds to the front of image forming apparatus 10, and the back side of the paper surface of Fig. 1 corresponds to the rear of image forming apparatus 10.

[0025] First, there will be described a general outline of the basic configuration of the image forming apparatus 10. As shown in Fig. 1, the image forming apparatus 10 includes an apparatus main body 12. An original reading device 14 is provided above the apparatus main body 12.

[0026] The document reading device 14 includes a document placement platform 16 formed of a transparent material. A document pressing cover 18 is attached above the document placement platform 16 via a hinge or the like so as to be freely opened and closed. The document pressing cover 18 is provided with an ADF (automatic document feeder) 24 that automatically feeds documents placed on a document placement tray 20 one by one to an image reading position 22. In addition, an operation unit 74 (FIG. 2) is provided on the front side of the document placement platform 16 for accepting input operations such as printing by a user via, for example, a touch display 75 (FIG. 2).

[0027] The document reading device 14 also includes an image reading section 26 that includes a light source, multiple mirrors, an imaging lens, a line sensor, etc., and generates image data based on the image of the document surface placed on the document placement table 16.

[0028] The apparatus main body 12 incorporates a control unit 28 for controlling each part of the image forming apparatus 10, an image forming unit 30, and the like.

[0029] The image forming section 30 includes an exposure unit 32, a developing device 34, a photoconductor drum 36, a cleaner unit 38, a charger 40, an intermediate transfer belt unit 42, an intermediate transfer belt 44, and a drive roller 46, and forms an image on paper. Image data for forming an image on paper is obtained from image data read by the image reading section 26 or image data transmitted from an external computer.

[0030] The image data handled by the image forming apparatus 10 corresponds to color images of four colors: black (K), cyan (C), magenta (M), and yellow (Y). For this reason, four of each of the developing device 34, the photoconductor drum 36, the cleaner unit 38, and the charger 40 are provided so as to form four types of latent images corresponding to each color, and these constitute four image stations.

[0031] The intermediate transfer belt unit 42 includes an intermediate transfer belt 44, a drive roller 46, a driven roller 48, and four intermediate transfer rollers 50, and is disposed above the photosensitive drums 36. The intermediate transfer belt 44 rotates (circularly moves) in a predetermined direction in accordance with the rotational drive of the drive roller 46. The intermediate transfer rollers 50 are disposed at positions facing each of the photosensitive drums 36 with the intermediate transfer belt 44 in between. During image formation, the intermediate transfer rollers 50 are used to transfer the toner images of each color formed on each photosensitive drum 36 to the intermediate transfer belt 44 in succession, superimposed on top of each other, thereby forming a multi-color toner image on the intermediate transfer belt 44.

[0032] The secondary transfer roller 52 is disposed to face the drive roller 46 across the intermediate transfer belt 44. When a sheet of paper passes through the secondary transfer nip between the secondary transfer roller 52 and the intermediate transfer belt 44, the toner image formed on the intermediate transfer belt 44 is transferred to the sheet of paper.

[0033] The fixing device 54 includes a fixing roller 56 and a pressure roller 58, and is disposed above (downstream in the paper transport direction) the secondary transfer roller 52. The fixing device 54 will be described in detail later.

[0034] Furthermore, within the device body 12, a first paper transport path L1 is formed for transporting paper from a paper feed tray 60 or a manual paper feed tray 62 as a paper feed section by a transport roller 64, passing through a registration roller 66, a secondary transfer roller 52 and a fixing device 54, and sending the paper to a paper discharge tray 68. Also, a second paper transport path L2 is formed for returning the paper after one-sided printing is completed and the paper has passed through the fixing device 54 to the first paper transport path L1 upstream of the secondary transfer roller 52 in the paper transport direction when performing double-sided printing on the paper.

[0035] Fig. 2 is a block diagram showing an electrical configuration of the image forming apparatus 10 shown in Fig. 1. Referring to Fig. 2, the image forming apparatus 10 includes a control unit .

[0036] The control unit 28 is essentially a computer, and includes a CPU 70 and a memory 72. The CPU 70 is responsible for the overall control of the image forming apparatus 10. The memory 72 includes a RAM, a ROM, a HDD (hard disk drive), and the like, although details are not shown. The CPU 70 is connected to a bus 73, and the RAM, ROM, HDD, and the like of the memory 72 are electrically connected to the bus 73. The CPU 70 executes various control programs in response to instructions from an operation unit 74, etc., to execute the operations of each unit of the image forming apparatus 10. The various control programs are stored in advance in the ROM or HDD, and are expanded into the RAM and executed as necessary. The RAM (not shown) of the memory 72 is also used as a work area and a buffer area for the CPU 70.

[0037] The bus 73 is further electrically connected to the document reading device 14, the image forming unit 30, the paper feeding unit 60 (62), and the like.

[0038] As described above, the document reading device 14 reads image information from the document placed on the document placement table 16, and outputs the image data to the image forming unit 30. The document reading device 14 also detects the paper size of the document, and outputs the detected size to the CPU 70 of the control unit 28.

[0039] As described above, the image forming unit 30 prints an image represented by the image data after image processing on paper supplied from the paper feed unit 60 (62).

[0040] Operation unit 74 is provided on the front surface of image forming apparatus 10, and includes input devices such as touch display 75, and outputs operation signals or operation data corresponding to the operations of these devices to CPU 70 of control unit 28. However, touch display 75 is a display having a touch panel built into its display surface, and when a touch operation (touch input) is performed within the effective touch range of the touch panel, it outputs touch coordinate data indicating the position of the touch input to CPU 70. Although not shown, a display control circuit that controls the display of touch display 75 is provided.

[0041] The image forming apparatus 10 is further provided, for example, near the operation unit 74 with an external memory interface (I / F) 76 for detachably mounting an external memory 77 such as a USB memory.

[0042] The communication unit 78 communicates with an external computer or the like via a network (not shown) in accordance with instructions from the CPU 70.

[0043] Here, with reference to FIG. 3, the configuration of the fixing device 54 will be briefly described below to the extent necessary for understanding the embodiment.

[0044] The fixing device 54 in this embodiment is, for example, an external roller heating type unit, and in addition to the fixing roller 56 and pressure roller 58, includes two heating rollers 80 and two thermostats 82 for preventing the rollers from overheating.

[0045] As an example, the fixing roller 56 has a three-layer structure including a cylindrical fixing core 56a made of, for example, stainless steel, a fixing elastic layer 56b provided with a constant thickness on the outer peripheral surface of the fixing core 56a, and a fixing release layer 56c provided with a constant thickness on the outer peripheral surface of the fixing elastic layer 56b.

[0046] The fixing roller 56 having such a configuration is rotatably supported by a supporting member (not shown), and a pressure roller 58 is provided so as to be in pressure contact with the outer circumferential surface of the fixing roller 56 .

[0047] The pressure roller 58 presses its outer circumferential surface against the outer circumferential surface of the fixing roller 56 to form a fixing nip portion Nf, which is a pressure contact portion between the pressure roller 58 and the fixing roller 56. The pressure roller 58 has a three-layer structure including, for example, a cylindrical pressure core metal 58a made of iron, a pressure elastic layer 58b provided with a constant thickness on the outer circumferential surface of the pressure core metal 58a, and a pressure release layer 58c provided with a constant thickness on the outer circumferential surface of the pressure elastic layer 58b.

[0048] Furthermore, inside the pressure roller 58, a heater 58d, such as a halogen lamp, is provided as a heat source for the pressure roller 58.

[0049] The pressure roller 58 is supported by a support member (not shown) so as to be rotatable parallel to the fixing roller 56 .

[0050] When the pressure roller 58 rotates in the direction indicated by the arrow in Fig. 3 (clockwise), the fixing roller 56 is driven to rotate in the direction indicated by the arrow in Fig. 3 (counterclockwise) and a sheet is sent to the fixing nip portion Nf therebetween.

[0051] The two heating rollers 80 are roller-shaped heating members for heating the fixing roller 56 to a predetermined fixing temperature, and as an example, have a two-layer structure including a cylindrical base material 80a made of, for example, stainless steel, and a protective layer 80b formed with a constant thickness on the outer peripheral surface of this base material 80a.

[0052] Furthermore, a heater 80c as a heat source is provided inside the heating roller 80. This heater 80c is, for example, a halogen lamp heater.

[0053] In this embodiment, the fixing device 54 with an external roller heating method is used. However, a fixing device with an internal heating method in which a heater is provided inside the fixing roller 56 or a belt heating method fixing device using a fixing belt instead of the fixing roller may also be used. That is, the embodiments of the present disclosure are applicable to all fixing devices having a fixing unit that sandwiches and conveys a sheet of paper at a fixing nip portion formed by a plurality of rotating members (for example, a heating roller or a heating belt and a pressure roller). In this case, the heating roller or the heating belt can be called a fixing rotating body, and the pressure roller can be called a pressure rotating body.

[0054] Here, referring to FIG. 4, for a full understanding of the present disclosure, the problems in such a fixing device will be described.

[0055] As shown in FIG. 4(A), for a fixing device using a fixing roller 56 having a dedicated width Wex (the width in a direction orthogonal to the sheet conveyance direction for sheets of a specific width size), when a sheet A having a sheet width Wex is used, a width Wex scratch 84a is generated on the surface of the fixing roller 56 due to rubbing of the sheet side edge (so-called "paper edge"). Even when this scratch 84a occurs, if a sheet having the same sheet width Wex is used, during printing, it is not affected by the scratch 84a of the fixing roller 56. That is, in this case, the scratch 84a of the fixing roller 56 caused by the paper edge of the sheet A does not cause any particular problem.

[0056] On the other hand, as shown in FIG. 4(B), for a fixing device using a fixing roller 56 having a dedicated width Wex, when a sheet B having a sheet width W (<Wex) is used, a new scratch 84b is generated on the surface of the fixing roller 56 due to the paper edge of the sheet B.

[0057] When the sheet A (sheet width Wex) is used again using the fixing roller 56 with such a scratch 84b, as shown in FIG. 4(C), there is a possibility that the scratch 84b with a width W may affect the sheet A. That is, there is a possibility that the stain (streak) 85 due to the scratch 84b may not be fixed on the printing surface of the sheet A.

[0058] Therefore, in order to prevent such printing defects, the above-mentioned Patent Document 1 prohibits printing using paper widths narrower than the dedicated width of the fixing roller, which causes the problem mentioned above.

[0059] In contrast, in the embodiment of the present disclosure, printing on paper B having a paper width W narrower than the dedicated width Wex of the fixing roller 56 is not prohibited.

[0060] However, if printing on narrow paper B is permitted in this way, the edge of the paper will scratch the surface of the fixing roller 56, but in this embodiment, the number of times printing is done with paper narrower than the dedicated width Wex of the fixing roller 56 (the number of papers that have passed through the fixing device 54; hereafter referred to as the "number of prints") is counted, and if the number of prints is less than a predetermined threshold, the scratches are deemed to be minor and will not affect print quality, such as scratches 84ab shown in Figure 5, and printing on paper A, which has a paper width Wex wider than paper B, is not prohibited. Note that in Figure 5, the number of short horizontal bars indicating scratches is less than the number of scratches 84b shown in Figure 4(B), for example, to indicate that scratches 84ab are minor.

[0061] In other words, in this embodiment, based on the count value of the number of prints, if the count value is less than a threshold value, even if printing is performed on a paper width Wex that is wider than the paper width W, it is considered that there is no effect on printing, and printing is permitted. Therefore, even if the paper width is narrower than the dedicated width of the fixing roller, printing can be continued without replacement. This reduces the possibility of burns occurring during replacement.

[0062] However, if printing continues as is, the count value of the number of prints will reach the above-mentioned threshold value that is determined as an index indicating that printing will be affected.

[0063] In this embodiment, after the count value of the number of prints reaches the threshold value, when using paper wider than the paper width at which the threshold value is reached, a question is asked as to whether printing is permitted.

[0064] Specifically, a message screen 86 with message 1 as shown in Fig. 6 is displayed on the touch display 75, and instructions from the user are awaited. This message screen 86 displays a message 87 saying, for example, "There may be streaks in the image. Do you want to allow printing?" along with a button 88y to be operated if printing is permitted and a button 88n to be operated if printing is not permitted. Thus, when faced with the message screen 86, the user need only touch button 88y to allow printing, or touch button 88n if printing is not permitted.

[0065] In other words, as described below, when it is determined in step S5 (corresponding to the first judgment section) that there is a paper width size for which the number of prints has reached a threshold, message screen 86 for message 1 functions as a first message screen that asks the user to confirm whether to allow printing even if there is a possibility of print defects (e.g., streaks) caused by scratches on the fixing roller 56.

[0066] However, if the user touches the button 88n, subsequent printing will become impossible, so in this embodiment, the user is advised to replace the fixing device 54. Specifically, a message screen 86 shown in Fig. 7(A) or Fig. 7(B) is displayed on the touch display 75 (Fig. 2).

[0067] A message screen 86 shown in FIG. 7A is a message screen for message 2 when control unit 28 of image forming apparatus 10 can display replacement procedures on touch display 75. In the example shown in FIG.

[0068] The message screen 86 for message 2 displays a message 87 saying "The fixing device needs to be replaced. Please replace it following the procedure below," as well as a replacement procedure display area 90p and a button 90s for instructing to stop printing. Therefore, a user who wants to continue printing can replace the fixing device by following the replacement procedure displayed in the replacement procedure display area 90p. On the other hand, a user who cannot or will not replace the fixing device can touch the stop button 90s. Note that if the button 90s is not operated within a certain time after the message screen 86 for message 2 is displayed, the replacement procedure is displayed in the area 90p. This is also true for the message screen 86 shown in FIG. 7(B).

[0069] A message screen 86 shown in FIG. 7B is a message screen of Message 3 when the control unit 28 of the image forming apparatus 10 cannot directly display the replacement procedure on the touch display 75.

[0070] The message screen 86 for this message 3 displays a message 87 saying "The fixing device needs to be replaced. Please access the following to replace it," along with a display area 90a showing how to access the replacement procedure and a button 90s for instructing to stop printing. Here, the access method displayed in the display area 90a may be, for example, a QR code (product name) showing the address of a site that can be accessed with a smartphone.

[0071] Therefore, a user who wants to continue printing can simply follow the access method displayed in the display area 90a to check the replacement procedure and replace the fixing device, whereas a user who wants to stop printing can simply touch the stop button 90s.

[0072] As in this embodiment, printing is permitted even when the fixing roller 56 is scratched by the edge of the paper in the following cases.

[0073] (1) For example, in list printing, test printing, or image quality adjustment, the presence of streaks in the printed matter 91 is acceptable.

[0074] (2) Also, as shown in FIG. 8A, if the effective range of the printed image on the printed matter 91 (paper length-margin length) is inside the scratch 84b on the fixing roller 56, the appearance of streaks is tolerable.

[0075] (3) Furthermore, as shown in Figure 8(B), if the portion containing streaks or the like is cut off by cutting after printing, it may be acceptable for the printed matter 91 to have streaks. For example, professional image forming devices may print on paper larger than the intended size, and then trim the edges to adjust the size after printing. In such cases, it may be acceptable for the printed matter 91 to have streaks.

[0076] 7(A) functions as a second message screen that recommends the user to replace the fixing device 54. Similarly, the message screen 86 of the message 3 shown in FIG. 7(B) functions as a third message screen that recommends the user to replace the fixing device 54.

[0077] The memory 72 shown in Fig. 2 has a program storage area 92 and a data storage area 94 as shown in Fig. 9. In the program storage area 92, a control program for the image forming apparatus 10 is stored.

[0078] The control programs of the image forming apparatus 10 include a display control program 96a, an operation detection program 96b, an image reading program 96c, an image forming program 96d, a fixing device management program 96e, and the like.

[0079] The display control program 96a is a program that generates display screen data necessary to display various screens on the screen of the touch display 75 (Figure 2) included in the operation unit 74 based on the display image generation data in the display image generation data memory area 98a described below, and uses the display screen data to display an image on the touch display.

[0080] The operation detection program 96b is a program for detecting operation data corresponding to an operation on the operation unit 74 (including the touch display 75) and storing the operation data in the operation data storage area 98b described below. For example, when the touch display 75 is touched, the control unit 28 (CPU 70) acquires touch coordinate data output from the touch display as operation data in accordance with the operation detection program 96b and stores the operation data in the operation data storage area 98b. When a hardware button or key (not shown) included in the operation unit 74 is pressed or operated, the control unit 28 acquires operation data resulting from the pressing or operation of the button or key in accordance with the operation detection program 96b and stores the operation data in the operation data storage area 98b.

[0081] The image reading program 96c controls an automatic document feeder (not shown) and the document reading unit 14 to read the document placed on the document placement table 16, and stores the data of the read document image in the temporary storage area 98c.

[0082] The image forming program 96d is a program that controls the image forming unit 30 to print image data on paper supplied from the paper feed unit 60 (62).

[0083] The fixing device management program 96e is a program for managing or controlling the image forming apparatus 10 including the fixing device 54 in accordance with a flow diagram shown in FIG. 10, which will be described later.

[0084] Although not shown, the program storage area 92 also stores other programs necessary for controlling the image forming apparatus 10.

[0085] In the data memory area 94, a display image generation data memory area 98a, an operation data memory area 98b, a temporary memory area 98c, a message screen data memory area 98d, a print count counter by paper width size 98e, and the like are set.

[0086] The display image generating data in the display image generating data storage area 98a includes polygon data and texture data for generating a display image, etc. The display image generating data also includes image data corresponding to software keys, image generating data for displaying each screen, etc.

[0087] The operation data in the operation data storage area 98b is operation data detected according to the operation detection program 96b, and is stored in chronological order. Note that the operation data is deleted after being used in the processing of the control unit .

[0088] The temporary storage area 98c temporarily stores image data read by the image reading unit 18, job data, and the like.

[0089] In the message screen data storage area 98d, data for displaying the message screen 86 for messages 1 to 3 shown in FIGS. 6 and 7 is preset.

[0090] The data storage area 98 further includes a paper width size print counter 98e, which counts the number of prints (i.e., the number of times the paper has passed through the fixing device 54) for each paper width size, such as A3, B4, A4, A4R, B5, B5R, etc., since the fixing device 54 was replaced. However, the paper size can be detected by a size sensor provided in the paper feed unit 60 (62).

[0091] In association with the paper width size-specific print count counter 98e, a paper width size-specific threshold value storage area 98f is provided, and this paper width size-specific threshold value storage area 98f stores a threshold value previously set for each of the above-mentioned paper sizes. The threshold value here is the aforementioned "threshold value" determined as an indicator that continued printing will affect printing. This threshold value may be set appropriately according to the thickness, hardness (strength of stiffness) and quality of the paper.

[0092] In addition, the data storage area 94 stores other data required for executing the control program of the image forming apparatus 10, and also includes flags and other counters and timers required for executing the control program.

[0093] Referring to FIG. 10, the operation of this embodiment will be described, in which a fixing device 54 including a fixing roller 56 having a dedicated width Wex as shown in FIG. 5 allows print jobs on paper with a width smaller than the dedicated width.

[0094] This operation starts when a print job (image formation job) is received based on a user instruction from the operation unit 74 or a print instruction from an external computer or mobile terminal, but for ease of illustration, the input of job contents in step S1 is shown as being executed after the start of the operation.

[0095] In step S1, the job contents of the print job including the paper size are input, and in the following step S3, the job data and other job information are input.

[0096] Thereafter, in step S5, the control unit 28, i.e., the CPU 70, refers to the paper width size-specific print count counter 98e and the paper width size-specific threshold storage area 98f to determine whether or not there is a paper width size for which the print count has reached the threshold. In other words, step S5 executed by the CPU 70 functions as a first determination unit that refers to the paper width size-specific print count counter 98e and the paper width size-specific threshold storage area 98f to determine whether or not there is a paper width size for which the print count has reached the threshold.

[0097] Although step S5 can be performed before the start, in this embodiment it is performed after step S3.

[0098] If the result of step S5 is "NO," that is, in step S7, the print job submitted in step S3 is executed. In step S7, the print job is executed for paper of any paper width size. For example, as shown in FIG. 5, the fixing roller 56 has a dedicated width Wex, and printing is permitted for paper widths (W) narrower than the dedicated width Wex. In this respect, a more user-friendly and easy-to-use image forming apparatus 10 is obtained, compared to Patent Document 1, which uniformly prohibits printing on paper widths (W) narrower than the dedicated width Wex.

[0099] When the CPU 70 judges "NO" in step S5 functioning as the first judgment section, the CPU 70 executes step S7 functioning as the first print job execution section. That is, step S7 executed when the first judgment section does not judge that there is a paper width size for which the number of prints has reached the threshold value functions as the first print job execution section.

[0100] Then, in the next step S9, the number of times printing was performed for the paper width size used in the print job executed in step S7 (the corresponding counter in the paper width size-specific printing number counter 98e) is incremented.

[0101] Steps S7 and S9 are executed until it is determined in step S11 that the job is complete, and when "YES" is determined in step S11, the CPU 70 stops the print job in step S13.

[0102] When the CPU 70 judges "YES" in the previous step S5, the CPU 70 judges in the next step S15 whether the paper width size input in step S1 is larger than the paper width size judged to have reached the threshold in step S5. When the CPU 70 judges "YES" in step S5 (first judgment section), that is, when the CPU 70 judges that there is a paper width size for which the number of times of printing has reached the threshold, the CPU 70 judges whether the paper width size is larger than the paper width size for which the number of times of printing has reached the threshold, and step S15 executed by the CPU 70 functions as a second judgment section.

[0103] As explained above, determining "NO" in step S15 means that even if there are scratches on the fixing roller 56, they will not affect printing, and so the process proceeds to execution of the print job in step S7. In this way, step S7, which executes a print job after determining "NO" in step S15 as the second judgment unit, functions as a second print job execution unit. In other words, when the number of prints for that paper width size is smaller (not larger) than the paper width size that has reached the threshold, step S7, which executes a print job for paper having that narrow paper width size, functions as a second print job execution unit.

[0104] Conversely, when the CPU 70 judges "YES" in step S15, it displays the message screen 86 of message 1 shown in Fig. 6 in the following step S17 to inform the user that streaks may appear in the image if the print job is continued as is, and then has the user decide whether or not to proceed with the print job. As described above, since the message screen 86 of message 1 shown in Fig. 6 is the first message screen, this step S17 functions as a first message screen display unit that displays the first message screen.

[0105] When the user touches button 88y on message screen 86 for message 1, a "YES" determination is made in step S19 based on the operation data in operation data storage area 98b, and when the user touches button 88n, a "NO" determination is made in step S19.

[0106] When the CPU 70 determines "YES" in step S19, the CPU 70 proceeds to the process of step S7, and the print job is executed. In this manner, step S7, which is executed when the user permits printing on the first message screen 86, functions as a third print job execution unit.

[0107] When the determination in step S19 is "NO", the CPU 70 in the following step S21 displays a second message screen 86 of message 2 shown in Fig. 7(A) and / or a third message screen 86 of message 3 shown in Fig. 7(B). The second message screen and the third message screen are both message screens for encouraging replacement of the fixing device 54, and step S21 functions as a replacement recommendation message screen display unit that displays a message screen recommending replacement of the fixing device 54.

[0108] In the next step S23, the CPU 70 determines whether or not the print cancel button 90s has been operated on the message screen 86 for message 2 or message 3. When the CPU 70 determines "YES" based on the operation data in the operation data storage area 98b, the process proceeds to step S13, where the print job is stopped.

[0109] When the step S23 data is determined to be “NO”, that is, when the user does not operate the print cancel button 90s on the message screen 86, the CPU 70 displays the replacement procedure for the fixing device 54 in the display area 90p of FIG. 7(A), or displays a method for accessing the replacement procedure for the fixing device 54 in the display area 90a of FIG. 7(B), in step S25.

[0110] Thereafter, the CPU 70 determines in step S27 whether or not the fixing device 54 has been replaced. This determination is made after a predetermined time has elapsed since the message screen 86 for message 2 or message 3 was displayed, which is the time required to replace the fixing device 54 plus a margin of time.

[0111] If "NO" is determined in step S27, that is, if the fixing device 54 has not been replaced even after the above-mentioned predetermined time has elapsed, the process proceeds to step S13, where the print job is stopped.

[0112] When the fixing device 54 is replaced, that is, when the determination is "YES" in step S27, the CPU 70 updates the information in the paper width size-specific print count counter 98e and the paper width size-specific threshold storage area 98f from the replaced fixing device. For example, if the replaced fixing device has already been used several times, scratches caused by the paper edge may be progressing. Therefore, it is conceivable to prepare a counter for each paper size for each fixing device, and to continuously increment the count value of the counter when the fixing device is replaced. In this case, the counter may be located either on the fixing device side or on the main body side.

[0113] When the counter is provided in the fixing device, it is preferable to set threshold information for the count value in the fixing device. For example, it is possible to set a counter and a storage area equivalent to counter 98e and threshold data storage area 98f shown in FIG. 9 in a computer chip (not shown) provided in the fixing device.

[0114] It should be noted that the processing of each step in the flow chart shown in FIG. 10 described above is merely an example, and the processing order of each step may be changed if the same results are obtained.

[0115] Also, in the above embodiment, a print count counter for each paper width size 98e is provided to count the number of prints (number of times passed through the fixing device 54) for each different paper width size, and the count value is compared with a threshold value to make a judgment in step S5 or the like. However, in another embodiment, the print count counter for each paper width size 98e may be configured to count the number of sub-scans by the image reading unit (scanner) 26, and compare the count value with a threshold value that is preset corresponding to that. In other words, a value corresponding to the number of prints can be obtained by counting the number of sub-scans.

[0116] As another embodiment, the life of the fixing device may be taken into consideration. Here, the life of the fixing device refers to the total number of sheets that can pass through the fixing device, or the cumulative operating time, that can guarantee print image quality regardless of paper size. Even if the number of prints has not reached the paper width size threshold when the job is input, if the life of the fixing device has been reached, the life of the fixing device may be given priority, and replacement of the fixing device may be prompted.

[0117] Furthermore, as another embodiment, the count value may be weighted. For example, when the paper type is set to thick paper or stiff paper type, the count when passing paper of that paper type may be doubled from the normal number of sheets passed, and when the paper type is set to thin paper or envelope, the count when passing paper of that paper type may be half the normal number of sheets passed. By weighting in this way, it is possible to maintain usability while maintaining high-precision print quality even if the degree of damage caused to the fixing device varies depending on the paper type.

[0118] Furthermore, the specific numerical values ​​and materials given above are merely examples and can be changed as appropriate according to the needs of the product specifications, etc. [Explanation of symbols]

[0119] 10...Image forming device 28 ... Control section 30...Image forming section 54... Fixing device 56 ... Fuser roller 58 ... Pressure roller 70...CPU 72…Memory 74...Operation unit 75 ... Touch display 98d ... Message screen data storage area 98e ... Print count counter by paper width size 98f ... Paper width size threshold memory area

Claims

1. An image forming apparatus including a fixing device including a fixing rotor having a dedicated width and a pressure rotor that contacts an outer circumferential surface of the fixing rotor to form a fixing nip between the fixing rotor and the pressure rotor, a counter for counting the number of sheets of paper that have passed through the fixing device for each paper width size; a first determination unit that refers to the counter and determines whether there is a paper width size for which the number of times of printing has reached a threshold value; a first print job execution unit that executes a print job when the first determination unit does not determine that there is a paper width size for which the number of prints has reached a threshold value; a second determination unit that, when the first determination unit determines that there is a paper width size for which the number of times of printing has reached a threshold, determines whether the paper width size is larger than the paper width size for which the number of times of printing has reached the threshold; and The image forming apparatus includes a second print job executing unit that executes a print job for paper having the paper width size when the second judgment unit determines that the paper width size is not larger than the paper width size for which the number of printings has reached a threshold value.

2. a first message screen display unit that displays a first message screen to ask a user to confirm whether to permit printing even if there is a possibility of a printing defect due to a scratch on the fixing rotating body, when the first determination unit determines that there is a paper width size for which the number of prints has reached a threshold value; and 2. The image forming apparatus according to claim 1, further comprising a third print job execution unit that executes a print job when the user permits printing.

3. 3. The image forming apparatus according to claim 2, further comprising a replacement recommendation message screen display unit that displays a replacement recommendation message screen recommending replacement of the fixing device to the user when the user does not permit printing on the first message screen.

4. 2. The image forming apparatus according to claim 1, wherein the counter is provided in the fixing device, and the threshold value is set in the fixing device.

5. A control program for an image forming apparatus including a fixing device including a fixing rotor having a dedicated width and a pressure rotor that contacts an outer circumferential surface of the fixing rotor to form a fixing nip between the fixing rotor and the pressure rotor, the control program comprising: a counter for counting the number of sheets of paper that have passed through the fixing device for each paper width size; a first determination unit that refers to the counter and determines whether there is a paper width size for which the number of times of printing has reached a threshold value; a first print job execution unit that executes a print job when the first determination unit does not determine that there is a paper width size for which the number of prints has reached a threshold value; a second determination unit that, when the first determination unit determines that there is a paper width size for which the number of times of printing has reached a threshold, determines whether the paper width size is larger than the paper width size for which the number of times of printing has reached the threshold; and a second print job execution unit that executes a print job for paper having the paper width size when the second determination unit determines that the paper width size is not larger than the paper width size for which the number of prints has reached the threshold value; and a control program for controlling the image forming apparatus to function as a control program for the image forming apparatus.

6. A control method for an image forming apparatus including a fixing device including a fixing rotor having a dedicated width and a pressure rotor that contacts an outer circumferential surface of the fixing rotor to form a fixing nip portion between the fixing rotor and the pressure rotor, the method comprising the steps of: Counting the number of sheets of paper that have passed through the fixing device for each paper width size; Referring to the counted value, it is determined whether there is a paper width size for which the number of times of printing has reached a threshold value; When it is not determined that there is a paper width size for which the number of times of printing has reached the threshold value, the print job is executed; When it is determined that there is a paper width size for which the number of times of printing has reached the threshold, it is determined whether the paper width size is larger than the paper width size for which the number of times of printing has reached the threshold, and When it is determined that the paper width size is not larger than the paper width size for which the number of printings has reached a threshold, a print job is executed for paper having the paper width size.

Images