Image forming apparatus and control program

Abstract

To prevent an image defect by eliminating wrinkles occurring in a fixing member.SOLUTION: An image forming apparatus 1 comprises: a fixing unit 26 that includes a first fixing member 261 heated by a heat source and a second fixing member 262 brought into pressure contact with the first fixing member 261 to form a fixing nip, and that heat-fixes a toner image on the recording material passing through the fixing nip; a receiving unit 23 that receives an instruction to execute a refresh mode that can be executed at a timing other than an image forming period; and a control unit 21 that, upon reception of the execution instruction, executes the refresh mode for driving to rotate the first fixing member 261 heated by the heat source 263 and the second fixing member 262 while bringing the members into pressure contact with each other.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and a control program. [Background technology]

[0002] In an electrophotographic image forming apparatus, a toner image is formed on a sheet of paper, and the toner image on the sheet is fixed by a fixing device, forming an image on the sheet. The fixing device forms a fixing nip by, for example, pressing fixing members such as two rollers together, and performs a fixing process in which the toner image is fixed to the sheet of paper by heating and pressurizing the sheet as the sheet passes through the fixing nip (for example, Patent Document 1).

[0003] When uneven paper is transported through such a fixing nip, wrinkles (partial deformation) may occur on the surface of the fixing member, and the wrinkles on the surface of the fixing member cause image defects due to uneven fixing. For example, uneven paper includes wrinkled or bent paper. Furthermore, when using continuous paper as in Patent Document 1, a seam is formed when, for example, temporarily cut paper is reconnected to clear a paper jam. At this seam, unevenness (steps) occurs due to the tape used for adhesion and overlapping of previous and next sheets of paper. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-55859 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the image forming apparatus of Patent Document 1 does not address the issue of wrinkles on the fixing member, and does not disclose how to eliminate wrinkles that occur.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide an image forming apparatus that can suppress image defects by eliminating wrinkles (partial deformation) that occur in the fixing member. [Means for solving the problem]

[0007] The above object of the present invention can be achieved by the following means.

[0008] (1) a fixing section including a first fixing member heated by a heat source and a second fixing member that is in pressure contact with the first fixing member to form a fixing nip, and that heat-fixes a toner image on a recording material that has passed through the fixing nip; a reception unit that receives an instruction to execute a refresh mode that can be executed at a timing other than during image formation; a control unit that, upon receiving the execution instruction, executes the refresh mode in which the first fixing member heated by the heat source and the second fixing member are rotationally driven while being in pressure contact with each other; An image forming apparatus comprising:

[0009] (2) The image forming apparatus according to (1), wherein the recording material is continuous paper.

[0010] (3) The image forming apparatus according to (1) or (2), wherein the refresh mode is executed in a state where there is no recording material in the fixing unit.

[0011] (4) the reception unit receives an instruction to execute the refresh mode from a user; The image forming apparatus according to any one of (1) to (3) above, wherein acceptance of the execution instruction is prohibited when the recording material is present in the fixing unit.

[0012] (5) The first fixing member and a pressure change mechanism for changing the pressure contact load between the first fixing member and the second fixing member are provided, The image forming apparatus according to any one of (1) to (4), wherein the control unit uses the pressure change mechanism to set the pressure contact load in the refresh mode to a load lower than the standard load during image formation.

[0013] (6) An image forming apparatus according to any one of (1) to (5), wherein the control unit sets the rotational drive speed of the first and second fixing members in the refresh mode to a speed faster than the standard speed during image formation.

[0014] (7) The image forming apparatus according to any one of (1) to (6), wherein at least one of the first and second fixing members has a PFA layer on its surface.

[0015] (8) A pressure change mechanism is provided to change the pressure load between the first fixing member and the second fixing member, The control unit, by the pressure change mechanism, After the image formation is completed, the first fixing member and the second fixing member are separated from each other, An image forming apparatus according to any one of (1) to (7), wherein when starting the execution of the refresh mode, the first fixing member and the second fixing member are changed from the separated state to a pressed state.

[0016] (9) A control program executed by a computer that controls an image forming apparatus having a fixing unit that includes a first fixing member heated by a heat source and a second fixing member that is in pressure contact with the first fixing member to form a fixing nip, and that heat-fixes a toner image on a recording material that has passed through the fixing nip, the control program comprising: a step (a) of receiving an instruction to execute a refresh mode that can be executed at a timing other than during image formation; a step (b) of executing the refresh mode in which the first fixing member heated by the heat source and the second fixing member are rotationally driven while being in pressure contact with each other, by receiving the execution instruction in the step (a); A control program for causing the computer to execute a process including the steps of:

[0017] (10) In the refresh mode executed in step (b), the control program described in (9) above sets the pressure contact load to a load lower than the standard load during image formation by a pressure change mechanism that changes the pressure contact load between the first fixing member and the first fixing member.

[0018] (11) The control program according to (9) or (10), wherein in the refresh mode executed in step (b), the rotational drive speed of the first fixing member and the second fixing member is set to a speed faster than the standard speed during image formation. [Effects of the Invention]

[0019] The image forming apparatus according to the present invention executes a refresh mode in which the first and second fixing members of the fixing unit heated by the heat source are pressed against each other while being rotated, thereby eliminating wrinkles (partial deformation) that have occurred in the fixing members, thereby suppressing image defects. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 1 is a block diagram of an image forming apparatus. [Figure 3] 3A to 3C are schematic diagrams for explaining the configuration of a fixing unit and each state. [Figure 4] 10 is a flowchart illustrating a refresh mode executed in the image forming apparatus. [Figure 5] 10 is an example of a selection screen for accepting an instruction to execute a refresh mode. [Figure 6] 5 is a subroutine flowchart showing the processing of step S17 in FIG. 4. [Figure 7] 10 is a table showing various fixing condition settings in a refresh mode and the time required to eliminate wrinkles. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. However, the scope of the present invention is not limited to the disclosed embodiment. In the description of the drawings, the same elements are given the same reference numerals, and redundant description will be omitted. Furthermore, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions. Furthermore, recording materials include continuous paper and cut (sheet) paper. Furthermore, the continuous paper may be long label paper in which an adhesive-coated label is attached to a long release paper.

[0022] Fig. 1 is a diagram showing a schematic configuration of an image forming apparatus 1 according to this embodiment. Fig. 2 is a block diagram showing a hardware configuration of the image forming apparatus 1. As shown in Fig. 1, the image forming apparatus 1 includes a supply device 10, an image forming apparatus main body 20, and a winding device 30, which are mechanically and electrically connected to each other.

[0023] (Feeding device 10, winding device 30) The supply device 10 includes a folder 11 to which a master roll 90 of continuous paper 91 (also referred to as roll paper) is detachably attached. The winding device 30 includes a folder 31 for winding up the continuous paper 91 fed from the master roll 90. The supply device 10 and the winding device 30 also include a control unit, a memory unit, a paper transport unit, and a communication unit (some components are not shown). These components have functions equivalent to the corresponding components of the image forming device main body 20, which will be described later. The supply device 10 feeds the continuous paper 91 from the master roll 90 attached to the folder 11 downstream of the transport path. The image forming device main body 20 forms an image on the fed continuous paper 91. The continuous paper 91, on which an image has been formed in the image forming device main body 20, is transported downstream to the winding device 30, where it is wound up and held in the folder 31.

[0024] The image forming device main body 20 includes a control unit 21, a memory unit 22, an operation display unit 23, a paper transport unit 24, an image forming unit 25, a fixing unit 26, a pressure change mechanism 27, and a communication unit 29, which are interconnected via signal lines.

[0025] (Control unit 21) The control unit 21 is a CPU, and controls each unit of the device and performs various arithmetic processing according to a program.

[0026] (Storage unit 22) The storage unit 22 includes a ROM for storing various programs and data in advance, a RAM for temporarily storing programs and data as a working area, and a hard disk for storing various programs and data.

[0027] (Operation display section 23) The operation display unit 23 is equipped with a touch panel, numeric keypad, start button, stop button, etc., and is used to display various information such as warnings and to input various settings and instructions. The user can also issue an instruction to execute a refresh mode from an external PC via the operation display unit 23 or the communication unit 29. In this case, the operation display unit 23 or the communication unit 29 functions as a reception unit that receives an instruction to execute the refresh mode. The refresh mode can be executed outside of image formation, and refreshes the fixing member to eliminate wrinkles that have appeared on its surface (the term "wrinkles" here includes partial deformation of the fixing member; the same applies below). Details of this refresh mode will be described later.

[0028] (Paper transport unit 24) The paper transport section 24 includes a transport path on which a plurality of transport rollers are arranged, and transports the continuous paper 91 by cooperating with the paper transport sections of the supply device 10 and the winding device 30 .

[0029] (Image forming unit 25) Image forming unit 25 forms images, for example, by electrophotography, and includes writing units, development units, and primary transfer units corresponding to each of the primary colors (yellow, magenta, cyan, and black), as well as an intermediate transfer belt and a secondary transfer unit. The toner images formed by development in the development units for each color are transferred onto the intermediate transfer belt (primary transfer) and are sequentially superimposed to form a full-color toner image. The full-color toner image is transferred onto continuous paper 91 by the secondary transfer unit. Note that, although an intermediate transfer belt type image forming unit is exemplified in this embodiment, a direct transfer type image forming unit that transfers images directly from a photosensitive drum to paper without an intermediate transfer belt may also be used.

[0030] (Communications Department 29) The communication unit 29 is an interface for communicating with other devices such as the supply device 10 and the winding device 30. The communication unit 29 also serves as an interface for network connection with an external device such as a PC.

[0031] (Fixing unit 26) FIG. 3 is a schematic diagram for explaining the configuration of the fixing unit 26 and each state set by the pressure change mechanism 27. As shown in FIG.

[0032] The fixing unit 26 heats and fixes the toner formed on the surface of the continuous paper 91 in the fixing nip N1. As shown in FIG. 3(a), the fixing unit 26 has a heating unit 261, a pressure unit 262, a temperature sensor 263, and a driving unit 264. The driving unit 264 is composed of a motor as a driving source and a gear mechanism that transmits the driving force of the motor, and rotates the pressure unit 262. The rotation of the pressure unit 262 also rotates (driven rotation) each component of the heating unit 261 accordingly. In the following description, the driving unit 264 is described as directly rotating the pressure unit 262, but this is not limited to this. For example, the driving unit 264 may directly rotate both the heating unit 261 and the pressure unit 262. In this case, the pressure unit 262 and the heating unit 261 may be independently driven by multiple motors.

[0033] Heating unit 261 is composed of heating roller 51, fixing belt 52, upper pressure roller 53, auxiliary roller 54, and heater 55. Heating unit 261 (particularly fixing belt 52) ​​functions as a first fixing member.

[0034] The heating roller 51 is a cylindrical metal roller, and has multiple heaters 55, such as halogen lamps, disposed inside as heat sources. The multiple heaters 55 have different light distributions in the axial direction. The heating roller 51, heated by the internal heaters 55, heats the fixing belt 52. The heated fixing belt 52 heats the paper as it passes through the fixing nip N1 together with the paper transported to the fixing unit 26. A temperature sensor 263 detects the surface temperature of the heated fixing belt 52. In the fixing unit 26, the control unit 21 controls the power supply to the heater 55, i.e., the lighting rate of the heater 55, so that the temperature detected by the temperature sensor 263 becomes a predetermined control temperature (fixing temperature). The control temperature is set to 160 to 200°C under standard conditions (during image formation) (set according to the basis weight and thickness of the paper).

[0035] Endless fixing belt 52 is stretched between heating roller 51, upper pressure roller 53, and auxiliary roller 54. Fixing belt 52 has an inner diameter of, for example, 168 mm. Fixing belt 52 is composed of, for example, an endless base substrate made of conductive PI (polyimide) and having a thickness of 70 μm, an elastic layer made of heat-resistant silicone rubber and having a thickness of anywhere between 100 and 400 μm provided on the outer surface of the base substrate, and a PFA layer (hereinafter also referred to as a PFA tube layer) having a thickness of anywhere between 10 and 40 μm formed by covering the elastic layer with a PFA (perfluoroalkoxy) tube, which is a heat-resistant resin, on top of the elastic layer.

[0036] The upper pressure roller 53 has an outer diameter of, for example, 90 mm. The upper pressure roller 53 is composed of, for example, a cylindrical core made of a metal such as iron, and a 20 mm-thick elastic layer made of heat-resistant solid silicone rubber on the outer surface of the core.

[0037] The auxiliary roller 54 is made of small-diameter metal or metal coated with heat-resistant rubber. The auxiliary roller 54 also functions as a tension roller, and is movable within a predetermined range of movement when a predetermined pressure is applied to the outside. The auxiliary roller 54 may be omitted.

[0038] The pressure applying unit 262 is composed of a lower pressure applying roller 59. The lower pressure applying roller 59 functions as a second fixing member. The lower pressure applying roller 59 has an outer diameter of, for example, 80 mm. The lower pressure applying roller 59 is composed of, for example, a cylindrical core made of a metal such as iron, a 6 mm thick elastic layer made of silicone rubber, which is a heat-resistant solid rubber, on the outer surface of the core, and a 30 μm thick PFA layer formed by covering the elastic layer with a PFA tube on top of that.

[0039] The lower pressure roller 59 is urged against the upper pressure roller 53 via the fixing belt 52 by the pressure changing mechanism 27. As a result, a fixing nip N1 is formed between the fixing belt 52 and the lower pressure roller 59.

[0040] (Pressure change mechanism 27) The pressure change mechanism 27 includes a biasing member such as a spring, a drive source such as a drive motor, a cam, an arm, etc. The pressure change mechanism 27 applies pressure between the pressure applying unit 262 and the heating unit 261 and changes the pressure load at that time. In addition, the pressure change mechanism 27 changes the pressure load between the pressure applying unit 262 and the heating unit 261, and sets the state of both to one of a pressed state, a separated state, and a lightly pressed state. Figure 3(a) shows the pressed state, Figure 3(b) shows the separated state, and Figure 3(c) shows the lightly pressed state.

[0041] The pressure contact state shown in Fig. 3(a) is used during image formation. Hereinafter, the pressure contact load at this time will also be referred to as the standard load. The pressure (load) between the pressure unit 262 and the heating unit 261 by the pressure change mechanism 27 at the standard load is, for example, 1000 N. The axial length of the fixing nip N1 is approximately 320 to 350 mm.

[0042] The separated state shown in Figure 3(b) is used when the printer is stopped and no image is being formed. In this separated state, the pressure change mechanism 27 moves the pressure unit 262 downward compared to the pressed state. Alternatively, the pressure change mechanism 27 moves the pressure unit 262 downward and the heating unit 261 upward. In the separated state, the heating unit 261 and the pressure unit 262 are not in contact with each other. Also, in the separated state, the heating unit 261 and the pressure unit 262 are not in contact with the continuous paper 91.

[0043] In the light pressure state shown in FIG. 3(c), the pressure change mechanism 27 reduces the biasing force of the pressure unit 262 on the heating unit 261. In the light pressure state, a load lower than the standard load is set (hereinafter also referred to as low load). For example, the low load is reduced to a fraction of the standard load. The light pressure state shown in FIG. 3(c) is used in the refresh mode, and this refresh mode is executed when the continuous paper 91 is not in the fixing unit 26 (fixing nip N1). For this reason, unlike FIGS. 3(a) and 3(b), the continuous paper 91 is not shown in FIG. 3(c).

[0044] (Refresh mode) Next, the refresh mode executed in the image forming apparatus 1 will be described with reference to FIGS.

[0045] Here, we will explain wrinkles in the fixing members of the fixing unit 26 in the refresh mode. The fixing belt 52 (first fixing member) and the lower pressure roller 59 (second fixing member) are each covered with a PFA tube as their uppermost layer (surface layer). When paper with unevenness, such as wrinkled paper or continuous paper 91 with a seam, passes through the fixing nip N1, wrinkles form on the surface of the fixing belt 52 or the lower pressure roller 59 due to the unevenness. In other words, wrinkles form in the PFA tube layer. These wrinkles are more likely to occur the thinner the PFA tube layer is, and also more likely to occur the thicker the elastic layer (silicone rubber layer) below the PFA tube layer is. Furthermore, the lower the temperature of the fixing member when the unevenness passes, the more likely the wrinkles are to occur (the more likely they are to remain as wrinkles). Unlike the heating unit 261, the pressure unit 262 does not have a heat source. Therefore, the temperature may be low. Due to these structural and temperature conditions, wrinkles in the lower pressure roller 59 are more likely to remain (recognized as a wrinkle phenomenon) than in the fixing belt 52, rather than immediately returning to their original state. These wrinkles in the fixing member cause uneven fixing, resulting in poor image quality. When poor image quality occurs due to wrinkles in the fixing member, the user can execute the following refresh mode to resolve the problem.

[0046] Fig. 4 is a flowchart showing the refresh mode. Fig. 5 is an example of a selection screen displayed on the operation display unit for receiving an instruction to execute the refresh mode.

[0047] (Steps S11 and S12) If the print job is completed (YES), the control unit 21 of the image forming apparatus 1 advances the process to step S12, and causes the pressure change mechanism 27 to switch the state of the fixing unit 26 from the previous pressed state to the separated state.

[0048] (Step S13) The control unit 21 determines whether or not there is paper (continuous paper 91) in the fixing unit 26 (particularly the fixing nip N1). This determination can be made based on the output of paper sensors (not shown) provided before and after the fixing unit 26 in the transport direction. If there is no paper in the fixing nip N1 (NO), the process proceeds to step S14; if there is paper (YES), the process proceeds to step S16.

[0049] (Steps S14 and S15) Here, the control unit 21 displays a refresh mode acceptance button and waits for acceptance from the user. FIG. 5(a) is an example of a selection screen d1 displayed on the operation display unit 23. The user can instruct execution of the refresh mode by operating the "Yes" button. When the control unit 21 accepts an instruction to execute the refresh mode from the user (YES), the process proceeds to step S17.

[0050] (Step S16) Here, if there is paper in the fixing nip N1, acceptance of the refresh mode is prohibited. In this case, the "Yes" button is grayed out and disabled, as shown in the selection screen d2 in Figure 5(b). After that, the process continues from step S13 onwards.

[0051] (Step S17) Here, the control unit 21 executes the refresh mode. Figure 6 is a subroutine flowchart showing the processing of step S17.

[0052] (Step S171) The control unit 21 sets the fixing conditions. The fixing conditions are (1) a constant load (light pressure contact state) lower than the standard load, (2) a rotation drive speed higher than the standard speed (during image formation), and (3) a control temperature of 180°C. For light pressure contact, the load is set to a small fraction of the standard load. For high speed, the load is set to anywhere between 120 and 150% of the standard speed.

[0053] (Step S172) Here, the control unit 21 switches the fixing unit 26 by the pressure change mechanism 27 from the separated state to the light pressure contact state (see FIG. 3(c) above).

[0054] (Step S173) Here, control unit 21 controls the driving of drive unit 264 and the power supply to heater 55 so as to achieve the fixing conditions set in step S171, and drives fixing unit 26 to rotate for a predetermined time under these fixing conditions. The predetermined time is, for example, one minute. After the predetermined time has elapsed, the fixing drive is stopped and the power supply to heater 55 is also stopped. This ends the subroutine flowchart, and the process returns to the main processing of FIG. 4 (END (RETURN)).

[0055] (Step S18) The control unit 21 causes the pressure change mechanism 27 to return the fixing unit 26 from the light pressure contact state to the separated state, and then the process ends (END).

[0056] (Each fixing condition) Next, the fixing conditions in step S171 will be described with reference to FIG. 7. FIG. 7 is a table showing various fixing condition settings in refresh mode and the time required to eliminate wrinkles. The fixing conditions were set as parameters: "control temperature," "rotational drive speed," and "pressure load." The control temperature for fixing is in the standard range (during image formation) of 160 to 200°C. The rotational drive speed is set to 120% at high speed, assuming that the standard speed during image formation is 100%. As mentioned above, the standard pressure load is 1000 N, and the low load for light pressure is one-fourth of that. As shown in FIG. 7, the higher the control temperature and the faster the rotational speed, the shorter the required time. Furthermore, the required time does not change even if the pressure load is changed. From the perspective of durability of the fixing member, a low temperature and low load are preferable. From the above perspectives, in this embodiment, condition 6, which involves a high rotational speed and a low load, was adopted (within the dashed frame in FIG. 7). However, if efficiency is not so important or durability is not so important, any of the other conditions 1 to 5 and 7 may be adopted.

[0057] As described above, the image forming apparatus according to the present embodiment includes a fixing unit that includes a first fixing member heated by a heat source and a second fixing member that is in pressure contact with the first fixing member to form a fixing nip and heat-fixes a toner image on a recording material that has passed through the fixing nip, a receiving unit that receives an instruction to execute a refresh mode that can be executed at a timing other than during image formation, and a control unit that, upon receiving the execution instruction, executes the refresh mode in which the first fixing member heated by the heat source and the second fixing member are rotated while being in pressure contact with each other. This eliminates wrinkles that have occurred in the fixing members, thereby making it possible to suppress image defects.

[0058] The configuration of the image forming apparatus described above is a description of the main configuration in explaining the features of the above embodiment, but is not limited to the above configuration and can be modified in various ways within the scope of the claims. Furthermore, configurations that are included in general image forming apparatuses are not excluded.

[0059] For example, in the above embodiment (FIG. 3, etc.), the pressure applying unit 262 did not have a heat source, but the pressure applying unit 262 may also have a heat source. For example, the lower pressure applying roller 59 may be a hollow roller with a built-in heater. Also, in the above embodiment, a fixing belt type fixing device was exemplified, but this is not limiting, and a roller pair type fixing unit may also be used. For example, the fixing belt may be omitted, and a heater may be built into the upper pressure applying roller 53. In this case, the upper pressure applying roller 53 functions as a heating roller. Furthermore, this heating roller (upper pressure applying roller 53) may be covered with a PFA tube as the top layer.

[0060] The means and methods for performing various processes in the image forming apparatus according to the above-described embodiments can be realized by either dedicated hardware circuits or a programmed computer. The programs can be provided, for example, by a computer-readable recording medium such as a USB memory or a DVD (Digital Versatile Disc)-ROM, or can be provided online via a network such as the Internet. In this case, the programs recorded on the computer-readable recording medium are typically transferred to and stored in a storage unit such as a hard disk. The programs can also be provided as standalone application software or can be incorporated into the software of the device as a function of the device. [Explanation of symbols]

[0061] 1. Image forming device 10 Feeding device 20 Image forming device main body 21 Control section 22 Memory section 23 Operation display section 24 Paper transport section 25 Image forming unit 26 Fixing section 261 Heating section 51 Heating roller 52 Fixing belt (first fixing member) 53 Upper pressure roller 54 Auxiliary roller 55 Heater 262 pressure unit (second fixing member) 59 Lower pressure roller 27 Pressure change mechanism 29 Communications Department 30 Winding device

Claims

1. a fixing section including a first fixing member heated by a heat source and contacting a toner image on a recording material, and a second fixing member pressure-contacting the first fixing member to form a fixing nip, and heat-fixing the toner image on the recording material that has passed through the fixing nip; a reception unit that receives an instruction to execute a refresh mode that can be executed at a timing other than during image formation; a control unit that, upon receiving the execution instruction, causes the heat source to heat the first fixing member to the same controlled temperature as that during normal image formation, and executes the refresh mode in which the heated first fixing member and the second fixing member are rotationally driven while being brought into pressure contact with each other; the second fixing member is a pressure roller having a PFA layer on its surface, the refresh mode is a mode for eliminating wrinkles in the PFA layer of the pressure roller, a pressure change mechanism that changes the pressure load between the first fixing member and the second fixing member; the control unit sets the pressure contact load in the refresh mode to a load lower than a standard load during image formation by the pressure change mechanism, the control unit sets the rotational drive speed of the first and second fixing members in the refresh mode to a speed higher than a standard speed during image formation. Image forming device.

2. 2. The image forming apparatus according to claim 1, wherein the recording material is continuous paper.

3. 3. The image forming apparatus according to claim 1, wherein the refresh mode is executed in a state where no recording material is present in the fixing unit.

4. the reception unit receives an instruction to execute the refresh mode from a user, 4. The image forming apparatus according to claim 1, wherein acceptance of the execution instruction is prohibited when the recording material is present in the fixing unit.

5. a pressure change mechanism that changes the pressure load between the first fixing member and the second fixing member; The control unit, by the pressure change mechanism, After the image formation is completed, the first fixing member and the second fixing member are separated from each other, 5. The image forming apparatus according to claim 1, wherein when execution of the refresh mode is started, the first fixing member and the second fixing member are changed from the separated state to the pressure contact state.

6. A control program executed by a computer for controlling an image forming apparatus having a fixing unit including a first fixing member that is heated by a heat source and contacts a toner image on a recording material, and a second fixing member that is in pressure contact with the first fixing member to form a fixing nip, and that heat-fixes a toner image on a recording material that has passed through the fixing nip, the second fixing member is a pressure roller having a PFA layer on its surface, a step (a) of receiving an instruction to execute a refresh mode, which is a mode for eliminating wrinkles in the PFA layer of the pressure roller and can be executed at a timing other than during image formation; a step (b) of executing the refresh mode in which, by receiving the execution instruction in the step (a), the first fixing member is heated by the heating source to the same controlled temperature as that during normal image formation, and the heated first fixing member and the second fixing member are rotationally driven while being in pressure contact with each other; A process comprising: In the refresh mode executed in step (b), the first fixing member and a pressure change mechanism that changes the pressure contact load between the first fixing member and the first fixing member are set to a load lower than a standard load during image formation; and a control program for causing the computer to execute a process of setting the rotational drive speeds of the first fixing member and the second fixing member to speeds higher than the standard speed during image formation;

Images