JP2018017885A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation apparatus which can notify of execution of cleaning at a more appropriate timing relevant to improvement of the conventional technique.SOLUTION: An image formation apparatus includes: an execution unit 10 which executes a cleaning mode of cleaning a pressure rotor by inverting the front and rear of a recording sheet by a conveyance unit and supplying the sheet to a fixation unit 27 after forming a prescribed toner image on one surface of the recording sheet by an image formation unit 200 and fixing the image by the fixation unit 27; a detection unit TH3 which detects the temperature of the pressure rotor; an operation unit 180 which performs notification for urging execution of the cleaning mode following the fact that the execution frequency of fixation processing to the recording sheet by the fixation unit 27 counted by a count unit C becomes equal to or greater than a prescribed value; and a reset unit D which resets the value counted by the count unit C following the fact that the execution frequency of the double-side mode executed in the state where the temperature detected by the detection unit TH3 is equal to or greater than the prescribed temperature becomes equal to or greater than the prescribed value.SELECTED DRAWING: Figure 8

Description

  The present invention relates to an electrophotographic image forming apparatus.

The image forming apparatus includes a fixing device that fixes an unfixed toner image formed on the sheet onto the recording material by applying heat and pressure to the sheet. In the fixing device, when a recording material (recording paper) containing a large amount of calcium carbonate (CaCO ₃ ) is used as the recording material, calcium carbonate is added to the surface of the fixing rotator and the surface of the pressure rotator together with the paper fibers. The toner adheres to the surface of the fixing rotator or the pressure rotator. When deposits (paper fibers, calcium carbonate, toner) on the surface of the fixing rotator or pressure rotator are accumulated, some of the deposits are transferred to the surface of the recording material and visually recognized as image defects. There is a fear.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a configuration in which an operation display unit displays that cleaning is required when a counter that counts the number of single-sided prints exceeds a predetermined value. Further, in Patent Document 1, since the pressure roller stain moves to a toner image formed on the first surface of double-sided printing and is discharged, the pressure roller becomes dirty when a certain number of double-sided printing is performed. It is determined that no cleaning is necessary.

JP 2014-89333 A

  The inventor has found that there is room for further improvement in the configuration of Patent Document 1 through examination. Although the present inventor has an effect that dirt on the pressure roller is less likely to be accumulated by performing double-sided printing, the temperature of the pressure roller is lower than that when the pressure roller is high. It has been found that the cleaning effect is weakened by executing double-sided printing.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that notifies the execution of cleaning at a more appropriate timing.

In order to achieve the above object, the first invention provides:
An image forming unit for forming an unfixed toner image on the recording paper;
A fixing rotator that is in contact with the surface of the recording paper having an unfixed toner image formed by the image forming unit, and a pressure rotator that forms a nip portion in cooperation with the fixing rotator, A fixing unit for fixing the toner image to the recording paper while nipping and conveying the recording paper at the nip portion;
A transport unit that reverses the front and back of the recording paper on which the toner image is fixed by the fixing unit and transports the recording paper again to the image forming unit and the fixing unit;
A predetermined toner image is formed on one side of the recording paper by the image forming unit, and this is fixed by the fixing unit. Then, the front and back sides of the recording paper are reversed by the conveying unit and supplied to the fixing unit. An execution unit for executing a cleaning mode for cleaning the pressure rotating body;
A detection unit for detecting the temperature of the pressure rotating body;
A counting unit that counts the number of executions of the fixing process to the recording paper by the fixing unit;
A notification unit for performing notification for urging the execution of the cleaning mode when the value counted by the count unit is equal to or greater than a predetermined value;
When the number of executions of the duplex mode in which the toner image is formed on both sides of the recording sheet executed in a state where the temperature detected by the detection unit is equal to or higher than a predetermined temperature becomes equal to or higher than a predetermined value, the count unit A reset unit for resetting the counted value;
It is characterized by having.

In addition, the second invention,
An image forming unit for forming an unfixed toner image on the recording paper;
A fixing rotator that is in contact with the surface of the recording paper having an unfixed toner image formed by the image forming unit, and a pressure rotator that forms a nip portion in cooperation with the fixing rotator, A fixing unit for fixing the toner image to the recording paper while nipping and conveying the recording paper at the nip portion;
A transport unit that reverses the front and back of the recording paper on which the toner image is fixed by the fixing unit and transports the recording paper again to the image forming unit and the fixing unit;
A predetermined toner image is formed on one side of the recording paper by the image forming unit, and this is fixed by the fixing unit. Then, the front and back sides of the recording paper are reversed by the conveying unit and supplied to the fixing unit. An execution unit for executing a cleaning mode for cleaning the pressure rotating body;
A detection unit for detecting the temperature of the pressure rotating body;
A counting unit that counts the number of executions of the fixing process to the recording paper by the fixing unit;
A notification unit for performing notification for urging execution of the cleaning mode when the value counted by the count unit reaches a predetermined value;
When the number of executions of the duplex mode in which the toner image is formed on both sides of the recording sheet executed in a state where the temperature detected by the detection unit is equal to or higher than a predetermined temperature becomes equal to or higher than a predetermined value, the count unit A reset unit for resetting the counted value;
It is characterized by having.

  According to the present invention, it is possible to provide an image forming apparatus that notifies the execution of cleaning at a more appropriate timing.

1 is a diagram illustrating an example of an image forming apparatus. FIG. 3 is a cross-sectional view illustrating an example of a fixing device. (A) is a figure which shows the structure of the longitudinal direction of an induction heating apparatus, (b) is a figure which shows the structure of the longitudinal direction of an internal core. FIG. 3 is a diagram illustrating a configuration in a longitudinal direction of a fixing device. FIG. 3 is a diagram illustrating an example of a pressure mechanism of the fixing device. FIG. 3 is a diagram illustrating a configuration of a fixing belt. It is a flowchart regarding cleaning mode. It is a block diagram which shows the structure which concerns on a control system. It is a figure which shows an example of the screen which inputs the execution instruction in cleaning mode. It is a flowchart regarding the integration of a counter. It is a flowchart regarding the integration of a counter. It is a flowchart regarding the integration of a counter.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the components described in this embodiment are merely examples, and the present invention is not limited to only those described in the embodiment.

[Example 1]
<Image forming apparatus>
FIG. 1 is a diagram illustrating an example of an image forming apparatus. The image forming apparatus 1 includes an image forming unit 200Y, 200M, 200C, and 200K that forms an image on a recording material by electrophotography, and a fixing process by applying heat and pressure to an unfixed image formed on the recording material. And a fixing device 27. In the present embodiment, the image forming apparatus 1 will be described as an example of an apparatus having a full-color intermediate transfer type image forming unit, but the present invention is not limited to this. For example, it may be a direct transfer type apparatus that directly transfers from the photosensitive drum 20 to the recording material without using an intermediate transfer belt 25 described later, or an apparatus that forms a single color toner image (for example, a monochrome machine). It may be. Further, the image forming apparatus 1 may be a copying machine, a printer, a facsimile machine, and a multifunction machine having a plurality of these functions.

  A reading device 160 is provided on the upper part of the image forming apparatus 1. The reading device 160 includes a document table (mounting unit) on which a document is placed by an operator, a document cover (cover unit) for shielding the placed document, and a CCD for reading image information of the document. An original reading unit is provided. In the image forming apparatus 1, an image is formed by the reading device 160 based on the image information read by the document reading unit when the operator inputs a copy start instruction via the operation unit 180. . In addition, information corresponding to the size, type, and number of sheets (recording paper) P on which a toner image is to be formed is input from the operation unit 180 by the operator. The designation of the size and type of the paper P on which the toner image is to be formed is not limited to that in which an instruction is input from the operation unit 180. For example, when there is no instruction from the operation unit 180, the size of the paper P on which the toner image is to be formed may be adjusted to the size of the original read by the reading device 160.

  Further, the image forming apparatus 1 of the present embodiment can also be used as a printer. Specifically, it is configured to be connectable to an external personal computer (not shown) via a LAN cable (communication line) (not shown), and based on image information inputted from the connected external personal computer, Execute image formation. At this time, CPU (Central Processing Unit) 10 also receives information corresponding to the size, type, and number of sheets P on which a toner image is to be formed from an external personal computer connected thereto. In the image forming apparatus 1, image formation is performed when image information is input from a connected external personal computer. In this case, the image forming apparatus 1 receives a print start instruction together with image information from an external personal computer. It should be noted that even if image information is input from a connected external personal computer, it is not immediately executed, and image formation may be started after a print start instruction is input from the operation unit 180.

  The operation unit 180 functions as input means for inputting various types of information by the operator and display means for displaying information. In this embodiment, the operation unit 180 includes an operation button unit 180A for inputting an instruction from the operator and a display unit (information display unit) 180B for displaying various messages and the like as shown in FIG. The display unit 180B is a touch panel type liquid crystal screen that displays various messages and various operation buttons (keys). Various settings for the printing operation performed by the image forming apparatus 1 are also input by the displayed operation buttons. Instructions such as copy start and print start by the operator are also input from the operation unit 180.

  The environmental sensor (detection unit) TH2 is a sensor that is installed inside the main body 1A of the image forming apparatus 1 and detects the ambient temperature at the installation location. The temperature detected by the environment sensor TH2 changes under the influence of the temperature of the surrounding environment (outside the main body 1A) where the apparatus is installed.

  Inside the main body 1A of the image forming apparatus 1, four image forming units 200Y, 200M, 200C, and 200K corresponding to the colors Y (yellow), M (magenta), C (cyan), and K (black) are connected in series. Is arranged. In other words, a tandem method is employed in which the processes up to the formation of a visible image are processed in parallel with each color of Y (yellow), M (magenta), C (cyan), and K (black).

  Hereinafter, in order to prevent the description from becoming complicated, the four image forming units of each color of Y, M, C, and K will be described by being represented by reference numeral 200, and the same applies to the following respective process means. Further, the arrangement order of the image forming units 200 for each color of Y, M, C, and K is not limited thereto.

  Each image forming unit 200 includes the following electrophotographic process means. That is, a photosensitive drum 20 as an image carrier that carries an electrostatic latent image on the surface corresponding to each color of Y, M, C, and K, a primary charging device 21, an exposure device 22, and a developing device 23. The primary transfer device 24 and a cleaning device (not shown) are provided.

  The photosensitive drum 20 is driven to rotate counterclockwise in FIG. The primary charging device 21 applies a voltage to uniformly charge the surface of the corresponding photosensitive drum 20. The surface of the charged photosensitive drum 20 is exposed by the exposure device 22 corresponding to the image data. As a result, an electrostatic latent image is formed on the photosensitive drum 20. Then, the electrostatic latent image on the photosensitive drum 20 is developed using toner (developer) by the developing device 23 and visualized as a toner image. In this embodiment, the toner is negatively charged by the developing device 23 and developed on the photosensitive drum 20.

  The toner image developed on the photosensitive drum 20 developed by the developing device 23 is sequentially superposed on an intermediate transfer belt (intermediate transfer member) 25 that is an endless belt by the primary transfer device 24 for primary transfer. After the primary transfer, the toner remaining on the photosensitive drum 20 is removed by a cleaning device (not shown).

  The full-color toner image formed on the intermediate transfer belt 25 by superimposing the toner images of all colors Y, M, C, and K is then fed to the secondary transfer device 26 by the secondary transfer device 26. Secondary transfer is performed collectively on paper (recording paper) P as recording material. The counter roller 34 inside the intermediate transfer belt 25 and the secondary transfer device 26 form a transfer nip portion via the intermediate transfer belt 25. The toner image formed on the intermediate transfer belt 25 is transferred to the paper P at the transfer nip portion by the secondary transfer device 26.

  Here, the paper (recording paper) P is an image on which the image forming apparatus 1 forms an image, and includes, for example, an envelope or the like in addition to plain paper, coated paper, cardboard, and thin paper. The image forming apparatus 1 may be configured to form an image on an OHP sheet or the like as a recording material in addition to the paper. Hereinafter, for convenience, description will be made using terms related to paper such as paper (recording paper), paper passing, paper feed, paper discharge, and the like. However, this means that at least paper can be used as the recording material, and the medium that can be used as the recording material is not limited to paper.

  The cassette 31 is a storage unit that stores paper P used for image formation. The paper feed roller 32 separates and feeds the paper P in the cassette 31 one by one. The paper P fed from the cassette 31 by the paper feed roller 32 is conveyed to the registration roller 33 and is temporarily stopped by the registration roller 33. The registration roller 33 allows the toner image on the intermediate transfer belt 25 to reach the transfer nip so that the toner image formed on the intermediate transfer belt 25 at the transfer nip is transferred to a predetermined position on the paper P. The paper P is sent out to the transfer nip portion in accordance with the timing.

  The paper P on which the toner image is transferred at the transfer nip portion is conveyed to a fixing device (fixing portion) 27.

  The fixing device 27 heats and pressurizes the paper P carrying an unfixed toner image while being nipped and conveyed at the fixing nip N. As a result, the fixing device 27 fixes the toner image on the paper P to the paper P. Details of the fixing device 27 will be described later.

  In the case of single-sided printing in which a toner image is formed on only one side of the paper P, the paper P fixed by the fixing device 27 is discharged by a paper discharge roller 35 onto a paper discharge tray 28 outside the apparatus.

  On the other hand, in the case of double-sided printing (double-sided mode) in which a toner image is formed on both sides (front side and back side) of the paper P, an image is also formed on the back side. Therefore, the sheet P on which the first side (front side) toner image has been fixed by the fixing device 27 is re-conveyed to the fixing device 27 by the conveyance unit including the reversing path 29, the double-sided path 30, the registration roller 33, and the like. The Specifically, the reversing path 29 having a reversing mechanism for reversing the paper P is reversed, and then conveyed to a double-sided path (conveying path) 30 having a conveying roller. Then, the sheet P on which the first side (front side) toner image is fixed by the fixing device 27 is conveyed again from the registration roller 33 to the transfer nip portion, and the toner image is transferred to the back side. Thereafter, the sheet P having the toner image transferred to the back side is fixed by the fixing device 27 and then discharged to the discharge tray 28 by the discharge roller 35.

<Fixing device>
Next, the configuration of the fixing device 27 will be described with reference to FIGS. FIG. 2 is a cross-sectional view illustrating an example of a fixing device. Fig.3 (a) is a figure which shows the structure of the longitudinal direction of an induction heating apparatus, FIG.3 (b) is a figure which shows the structure of the longitudinal direction of an internal core. FIG. 4 is a diagram illustrating a configuration in the longitudinal direction of the fixing device. FIG. 5 is a diagram illustrating an example of a pressure mechanism of the fixing device.

  The fixing belt 100 as a fixing rotating body (rotating body) and the pressure roller 600 as a pressure rotating body (rotating body) cooperate to form a fixing nip portion N as a pair of rotating bodies. Here, the fixing rotator is a rotator on the side of the pair of rotators that comes into contact with the surface having an unfixed toner image on the paper (recording paper) P. An induction heating device 300 described later causes the fixing belt 100 to generate heat. The fixing belt 100 is an endless belt having a metal layer and is induction-heated by an induction heating device 300 described later. The pressure roller 600 is disposed in contact with the outer periphery of the fixing belt 100. The pad member 101 provided inside the fixing belt 100 applies a pressing force to the pressure roller 600, so that the fixing belt 100 and the pressure roller 600 form a fixing nip portion N. The fixing device 27 fixes the paper P by applying heat and pressure to the paper P carrying the toner image by nipping and conveying the paper P at the fixing nip portion N. The fixing belt 100 is in contact with a surface (sheet surface) on the side of the paper P that carries an unfixed toner image.

  The pad member 101 is a member that forms a fixing nip portion N by applying a pressing force between the fixing belt 100 and the pressure roller 600, and is held by a metal stay 102. The pad member 101 is a heat-resistant resin, and holds the fixing pad 103 on the pressure roller 600 side. The fixing pad 103 is made of a material having high hardness such as a metal such as stainless steel or ceramics, and has a shape extending in the longitudinal direction of the fixing belt 100 with a thickness of about 1 mm.

  The separation guide 106 is a guide member provided on the downstream side of the fixing nip portion N in the conveyance direction of the paper P so that the paper P passing through the fixing nip portion N does not wind around the fixing belt 100. The separation guide 106 is arranged with a certain gap (gap) from the fixing belt 100 so that the fixing belt 100 is not damaged by contact with the fixing belt 100. The separation guide 106 engages with a part of the flange 105 and is fixed by a biasing means such as a spring.

  The heat equalizing roller (heat equalizing member) 349 is a metal roller for preventing an excessive temperature rise at the end in the longitudinal direction of the fixing belt 100 via the pressure roller 600. The soaking roller 349 is preferably made of a material having a thermal conductivity of 100 W / m · K or more at 100 to 250 ° C. and a heat capacity of 3.0 kJ / m 3 · K or less at 100 to 250 ° C. The soaking roller 349 is a roller that can be driven and rotated by the pressure roller 600, and dissipates the heat of the pressure roller 600 in the longitudinal direction by contacting the pressure roller 600. The soaking roller 349 is rotated by the friction of the surface of the pressure roller 600 and is driven to rotate by the pressure roller 600. The soaking roller 349 can be in a state of contacting the pressure roller 600 by a contact / separation mechanism (not shown) and a state of being separated from the pressure roller 600.

  The cleaning device 350 is a cleaning member that cleans the soaking roller 349. The cleaning device 350 includes two aluminum pipes 351 and 352 that wind up web paper, a web paper 354, a cleaning roller 353 that is a sponge roller, and a web feed mechanism (not shown). As the web paper 354, specifically, a nonwoven fabric made of methane-based aramid fibers can be used. Further, the web paper 354 wound around the aluminum pipe 351 is fed in the direction of arrow A by the web feeding mechanism and wound around the roller on the aluminum pipe 352 side.

  The temperature sensor (detection unit) TH3 is a temperature sensor that detects the surface temperature of the pressure roller 600. The temperature sensor TH3 is connected to the CPU 10. The pressure roller 600 is provided in a non-contact manner on the surface at the center in the longitudinal direction. The temperature sensor TH3 is a temperature detection element such as a thermistor, for example. The temperature sensor TH3 may be configured to contact the surface of the pressure roller 600.

(Induction heating device)
The induction heating device 300 is a heating source (heating unit) that induction heats the fixing belt 100. The induction heating device 300 includes an exciting coil 301, an outer magnetic core 302, a coil holding member 303, and a power supply device (not shown). The exciting coil 301 is formed by using, for example, a litz wire as an electric wire, which is horizontally long and shaped like a ship bottom and is opposed to a part of the peripheral surface and side surface of the fixing belt 100. The power supply device (excitation circuit) applies a high-frequency current of 20 to 60 kHz to the excitation coil 301 while the fixing belt 100 is rotating. The metal layer (conductive layer) of the fixing belt 100 is inductively heated by the magnetic flux generated by the exciting coil 301 due to the high-frequency current. The outer magnetic core 302 covers the exciting coil 301 so that the magnetic flux generated by the exciting coil 301 does not substantially leak except for the metal layer (conductive layer) of the fixing belt 100. The outer magnetic core 302 has a high magnetic permeability material such as ferrite that shields the magnetic flux so that the magnetic flux generated by applying a high-frequency current to the exciting coil 301 can be used for heating the fixing belt 100 more efficiently. Made from.

  The coil holding member 303 is an electrically insulating resin having a thickness of about 2 mm that supports the exciting coil 301 and the outer magnetic core 302. The induction heating device 300 is disposed on the upper surface of the outer peripheral surface of the fixing belt 100 with a predetermined gap (gap) therebetween.

  Further, an inner core 104 is provided on the coil side of the stay 102 inside the fixing belt 100 in order to perform induction heating more effectively. The inner core 104 is made of a high permeability material such as ferrite that shields the magnetic flux so that the magnetic flux generated by applying a high-frequency current to the exciting coil 301 can be used for heating the fixing belt 100 more efficiently. ing.

  In addition, the fixing device 27 includes a temperature sensor TH1 that detects the temperature of the fixing belt 100. The temperature sensor TH1 is a temperature detection element such as a thermistor, for example. The temperature sensor TH <b> 1 is provided in contact with the inner surface of the fixing belt 100 at the longitudinal center of the fixing belt 100. The temperature sensor TH1 is connected to the CPU 10. Based on the detected temperature input from the temperature sensor TH1, the CPU 10 controls the power input to the exciting coil 301 by the power supply device so that the fixing belt 100 is maintained at a target temperature (for example, 180 ° C.). Yes. In the present embodiment, the CPU 10 changes the frequency of the high-frequency current input by the power supply device based on the detection value of the temperature sensor TH1 so that the temperature is constant at 180 ° C., which is the target temperature of the fixing belt 100.

  In this embodiment, the induction heating apparatus 300 using the electromagnetic induction method is provided as the heating unit for the fixing belt 100. However, the heating unit for the fixing belt 100 is not limited thereto. For example, a heating source such as a halogen heater, a ceramic heater, or an infrared lamp may be provided inside the fixing belt 100. Further, the heating source of the fixing belt 100 may be provided outside the fixing belt 100.

(Fixing belt)
FIG. 6 is a diagram illustrating the configuration of the fixing belt of the fixing device, and shows a cross section of the fixing belt 100. The fixing belt 100, which is an endless belt, includes a sliding layer 100d, a base layer 100a, an elastic layer 100b, and a release layer 100c in that order from the inside to the outside.

  The base layer 100a is a metal layer having an inner diameter of about 20 to 40 mm. As the base layer 100a of the fixing belt 100, an iron alloy, a nickel alloy, copper, silver, or the like can be appropriately selected. The fixing belt 100 of this embodiment has an outer diameter of 30 mm, and an inner diameter of the base layer 100a is about 29.6 mm.

  The elastic layer 100b provided on the outer periphery of the base layer 100a is a heat resistant rubber layer. The thickness of the rubber layer is preferably set within a range of 100 to 800 μm. In the present embodiment, the thickness of the rubber layer is set to 200 μm in consideration of reducing the heat capacity of the fixing belt 100 to shorten the warm-up time and obtaining a suitable fixed image when fixing a color image. Yes.

  A release layer 100c is provided as a surface layer on the outer periphery of the elastic layer 100b, and the surface resistance of the fixing belt 100 is 1.0E + 6 (Ω) or more. The release layer 100c is a fluororesin (for example, PFA (perfluoroalkoxy fluororesin) or PTFE (polytetrafluoroethylene)) layer. The release layer 100c is a surface layer of the fixing belt 100 and enhances the release property with respect to the toner. Moreover, the thickness of the release layer 100c is 40 μm. The release layer 100c may be configured to contain carbon black in addition to the fluororesin as long as the above surface resistance is satisfied.

  Further, on the inner surface side of the base layer 100a, a sliding layer 100d having a high sliding property may be provided in an amount of 10 to 50 μm in order to reduce the sliding friction with the temperature sensor TH1. In this embodiment, a 30 μm polyimide layer is provided as the slipping layer 100d, and heat-resistant grease as a lubricant is applied to the surface thereof. Thereby, the lubricity of the inner surface of the fixing belt 100 is maintained.

(Pressure roller)
A pressure roller (pressure rotator) 600 that forms a fixing nip portion N with the fixing belt 100 includes a metal core 600a having an outer diameter of 30 mm, an elastic layer 600b that is a rubber layer, and a mold release. A layer 600c is provided. The release layer 600c is a surface layer of the pressure roller 600, and is a fluororesin layer (for example, PFA or PTFE).

(Pressure mechanism)
The fixing device 27 includes a pressure mechanism 500 that presses the pad member 101 toward the pressure roller 600 in order to form the fixing nip portion N. Both ends of the stay 102 that holds the pad member 101 are fixed to the flange 105. The pressurizing mechanism 500 applies pressure to the flange 105 by a pressurizing spring 508.

  FIG. 5 is a view showing an example of a pressure mechanism of the fixing device, and shows one end side of the fixing device 27 in the longitudinal direction. The pressure mechanism 500 includes a pressure cam 501, a pressure plate rotation shaft 502, a pressure cam rotation shaft 504, a pressure plate 505, a pressure adjustment screw 506, a pressure support plate 507, and a pressure spring 508.

  The pressure support plate 507 is supported by the pressure plate rotation shaft 502 passing through the front side plate 400 and the rear side plate 401, and the front end 507 a provided at the front end of the pressure support plate 507 It is fixed to each of the side plate 400 and the rear side plate 401 by means such as screws.

  The pressure plate 505 is supported by a pressure plate rotation shaft 502, and is provided so as to be rotatable about the pressure plate rotation shaft 502 with respect to the pressure support plate 507.

  The pressure spring 508 is a spring that applies a load to the pressure plate 505. A pressure adjusting screw 506 is fastened to the pressure support plate 507. The seating surface of the pressure adjusting screw 506 shortens the spring length of the pressure spring 508 and applies a load to the pressure plate 505. Since the pressure plate 505 is rotatably supported with respect to the pressure support plate 507 as described above, a moment is generated around the pressure plate rotation shaft 502 by the compression force of the pressure spring 508.

  Since the pressure plate 505 is disposed so as to contact the flange 105, the flange 105 is pushed toward the pressure roller 600 by a moment generated in the pressure plate 505, and the fixing nip is interposed between the pressure roller 600 and the fixing belt 100. Part N will be formed.

  The pressure applied by the pressure plate 505 to the flange 105 can be released by the pressure cam 501 pushing up the pressure plate 505. When releasing the pressure, the pressure cam 501 having a predetermined eccentric amount rotates about the pressure cam rotation shaft 504 to push up the pressure plate 505 and release the contact between the pressure plate 505 and the flange 105. The pressure plate 505 is rotated until it is done. As a result, the applied pressure is released. Further, the pressure cam 501 is rotated from the state in which the pressure is released, and the pressure plate 505 is brought into contact with the flange 105, whereby pressure (for example, 550 N) is applied.

  The pressurizing cam rotating shaft 504 is connected to a motor M1 of a pressurizing mechanism as a drive source, and the pressurizing cam 501 is rotated by rotating the pressurizing cam rotating shaft 504 by the motor M1 of the pressurizing mechanism. Rotate. The motor M1 of the pressure mechanism is electrically connected to the CPU 10, and the CPU 10 determines the position of the pressure cam 501 by operating the motor M1 of the pressure mechanism. The pressurizing mechanism 500 can take a pressurized state where the pressurizing plate 505 applies pressure to the flange 105 and a released state where the pressurizing force is released.

  In FIG. 5, the one end side in the longitudinal direction of the fixing device 27 has been described. However, as shown in FIG. 4, a similar pressure mechanism 500 is provided on the other end side in the longitudinal direction. The pressure cam rotating shaft 504 and the pressure cam 501 on the other end side are also connected. The motor M1 of the pressure mechanism rotates the pressure cams 501 at both ends simultaneously by rotating the pressure cam rotation shaft 504. Thereby, the pressurization mechanisms 500 at both ends can be simultaneously pressed, and the pressurization mechanisms 500 at both ends can be simultaneously released.

  Further, the fixing device 27 includes a drive motor M <b> 2 that rotates the pressure roller 600. The drive motor M2 is connected to the metal core 600a of the pressure roller 600, and when the pressure roller drive motor M2 is driven, the pressure roller 600 is rotationally driven. The CPU 10 is connected to the drive motor M2 and controls the rotation / stop of the pressure roller drive motor M2. The fixing belt 100 rotates following the pressure roller 600.

  Here, the operation of the fixing device 27 when executing the image forming process corresponding to the input print command will be summarized. Here, the print command is an execution command for image forming processing to the image forming unit 200. The print command is, for example, a print start instruction input from the operation unit 180 or an external personal computer by the operator, or a copy start instruction input from the operation unit 180 by the operator.

  First, the CPU 10 drives the motor M <b> 1 of the pressure mechanism so as to press the pressure roller 600 against the fixing belt 100 to form the fixing nip portion N.

  In a state where the fixing nip portion N is formed, the CPU 10 rotates the pressure roller 600 by the pressure roller driving motor M2 to rotate the fixing belt 100 in a driven manner. The CPU 10 maintains the fixing belt 100 at a predetermined temperature by the induction heating device 300.

  In this state, the fixing device 27 fixes the toner image on the sheet P by nipping and conveying the sheet P carrying the unfixed toner image conveyed from the transfer nip part side at the fixing nip part N. . When the fixing process is continuously performed on a plurality of sheets P, the fixing belt 100 continues to rotate until the last sheet P has passed through the fixing nip N.

  When the last sheet P for the image forming process to be executed has passed through the fixing nip N, the CPU 10 stops the rotation of the pressure roller 600 and releases the pressure applied by the pressure mechanism 500.

<Dirt on pressure roller>
In particular, when a sheet having a high content of calcium carbonate (CaCO ₃ ) is used as the recording material, in the fixing device 27, calcium carbonate adheres to the surface of the fixing belt 100 and the surface of the pressure roller 600 together with the paper fibers. Further, toner adheres to the surface of the fixing belt 100 and the surface of the pressure roller 600. In particular, when calcium carbonate adheres to the surface of the fixing belt 100 or the surface of the pressure roller 600, the releasability of the surface is lowered, so that the toner is more likely to adhere. Therefore, toner, paper fibers, and calcium carbonate may gradually accumulate on the surface of the fixing belt 100 and the surface of the pressure roller 600 as dirt. If the dirt accumulated on the surface of the fixing belt 100 or the surface of the pressure roller 600 is transferred to the surface of the recording material, there is a possibility that an image defect at a level visually recognized by the user may occur.

  Here, the toner offset to the surface of the fixing belt 100 or the surface of the pressure roller 600 at the previous printing is heated to the softening point or more at the next printing. Further, at the time of printing, the toner on the recording material is heated to the softening point or more at the fixing nip portion N.

  Therefore, the toner offset on the surface of the fixing belt 100 is transferred to the toner image on the recording material little by little together with paper fibers such as paper fibers and calcium carbonate adhering to the surface of the fixing belt 100 at the next printing, and discharged. Is done. Here, since the transfer of the offset toner from the surface of the fixing belt 100 to the recording material is a minute amount, even if it adheres to the recording material, it is not visually recognized as an image defect.

  On the other hand, the toner offset to the surface of the pressure roller 600 is transferred to a recording material little by little by two-sided printing, and is discharged. This is because in the case of duplex printing, the toner image formed on the first surface contacts the pressure roller 600 during the fixing process on the second surface. However, in the case of single-sided printing, the surface of the pressure roller 600 does not come into contact with the surface of the recording material carrying the toner image, so the toner and paper dust are likely to remain on the surface of the pressure roller 600. , Dirt is easy to accumulate.

  Therefore, the image forming apparatus 1 can execute a cleaning mode (cleaning mode) in order to remove dirt accumulated on the surface of the pressure roller 600.

  The fixing device 27 according to the present exemplary embodiment includes the cleaning device 350 that contacts the soaking roller 349. However, the cleaning device 350 alone cannot remove the dirt on the surface of the pressure roller 600 via the soaking roller 349. There is a case. For example, the dirt on the surface of the pressure roller 600 may stick to the surface of the pressure roller 600 due to the pressure at the nip portion between the fixing nip portion N and the soaking roller 349. Therefore, even when the cleaning device 350 is provided, it is preferable that the cleaning mode can be executed as in this embodiment.

<Cleaning mode>
A cleaning mode for cleaning the surface of the pressure roller 600 will be described with reference to a flowchart shown in FIG. 7 and a block diagram shown in FIG.

The CPU 10 forms a predetermined toner image on one side of the recording paper, fixes the toner image by the fixing device 27, reverses the front and back of the recording paper by the conveyance unit, and supplies the reverse to the fixing device 27. Execute the cleaning mode to clean.
The control shown in the flowchart is performed by the CPU 10 functioning as an execution unit executing a control program stored in a built-in storage unit. As shown in FIG. 8, the CPU 10 is electrically connected to the image forming unit 200 and the fixing device 27, and controls the image forming operation and the fixing operation by the image forming unit 200. The CPU 10 is electrically connected to the operation unit 180. Further, the CPU 10 is electrically connected to a transport mechanism including a paper feed roller 32, a registration roller 33, a reverse mechanism of the reverse path 29, a transport roller of the double-sided path 30, a paper discharge roller 35, and the like. To control.

  When the operator inputs an instruction to execute the cleaning mode to the operation unit 180 (S101), the CPU 10 starts executing the cleaning mode. Specifically, as will be described later with reference to the flowchart, the CPU 10 executes the cleaning mode as shown in FIG. 9 when the cleaning counter C (details will be described later) exceeds a predetermined value. Is displayed on the display unit 180B. FIG. 9 is a diagram illustrating an example of a display screen. The operator instructs the image forming apparatus 1 to execute the cleaning mode by pressing the execution key 180C displayed on the display unit 180B. That is, the operation unit 180 functions as a reception unit that receives an instruction to execute the cleaning mode. If no cleaning execution instruction is input, cleaning is not executed. In this embodiment, the execution instruction is input via the operation unit 180. However, the execution instruction may be input from an externally connected PC connected to the image forming apparatus 1 via a network.

  When the execution instruction for the cleaning mode is input, the CPU 10 warms up the fixing device 27. Here, the warm-up is a preparatory operation for causing the fixing device 27 to shift to a state where the fixing process can be started. Specifically, the heating operation of the fixing belt 100 is performed by the induction heating device 300.

  When the temperature of the fixing belt 100 reaches the target temperature (180 ° C. or higher) (S103 Yes), the CPU 10 drives the paper feed roller 32 to feed a recording material (cleaning sheet) for cleaning from the cassette 31 ( S104). The temperature of the fixing belt 100 is detected by a temperature sensor TH1.

  Note that the temperature value (180 ° C.) of the fixing belt 100 is an example, and is not limited thereto. In order to further heat the pressure roller 600, the conveyance of the cleaning sheet may be started after a predetermined time has elapsed after reaching 180 ° C.

  In parallel with the heating operation of the fixing device 27, a preparatory operation for causing the image forming unit 200 to shift to a state where the image forming process can be started is also performed. If the preparation operation of the image forming unit 200 is not completed even when the preparation operation of the fixing device 27 is completed, the CPU 10 may wait for completion of the preparation operation of the image forming unit 200 before proceeding to S104. Good.

  Note that the cleaning sheet does not have to be a special sheet exclusively for cleaning. For example, plain paper may be used. The recording material to be fed as the cleaning sheet may be selected by the operator when the cleaning mode is executed, or the CPU 10 automatically selects the recording material based on the preset priority order. It is good also as composition to do.

  In step S105, the CPU 10 conveys the supplied cleaning sheet to the transfer nip portion, and forms a black solid image on the first surface of the cleaning sheet. In this embodiment, the solid image for cleaning is formed in black, but the color is not limited to this.

  Further, in order to clean the entire circumference of the pressure roller 600, it is preferable to set the length of the cleaning solid image in the conveyance direction of the recording material longer than the circumference of the pressure roller 600. In addition, the length in the direction orthogonal to the conveyance direction of the recording material for the solid image for cleaning (hereinafter referred to as the width direction) is preferably the maximum width in which the image forming apparatus 1 can form an image. Therefore, it is preferable to use a recording material whose length in the width direction (width direction size) is the maximum width that can be used in the image forming apparatus 1 for the cleaning sheet.

  In this embodiment, Canon CS-680 having A3 size and basis weight of 68 g / m 2 is used as the cleaning sheet. In the cleaning mode, the CPU 10 forms an image so that the margin area in the width direction is minimized (in the present embodiment, the margin in the width direction is 2 mm in width, respectively). Further, the margins at the front end and the rear end in the transport direction were set to 10 mm.

  In S <b> 106, the CPU 10 conveys the cleaning sheet to the fixing device 27 and causes the fixing device 27 to fix the black solid image formed on the first surface of the cleaning sheet.

The CPU 10 reverses the front and back of the cleaning sheet on which the first solid image has been fixed by the fixing device 27 through the reverse path 29 and conveys it to the double-sided path 30 (S107). Then, the CPU 10 conveys the cleaning sheet to the fixing device 27 so that the first surface of the cleaning sheet (the surface on which the image is formed in S105) is in contact with the pressure roller 600 (S108). Note that it is not necessary to form a toner image on the second surface of the cleaning sheet. In S <b> 108, the solid image fixed on the first surface of the cleaning sheet is melted again by passing through the fixing device 27. When the melted solid image comes into contact with the pressure roller 600, the toner stains and CaCO ₃ particles adhering to the surface of the pressure roller 600 are moved to the cleaning sheet by the adhesive force of the melted toner. Thereby, the surface of the pressure roller 600 can be cleaned.

  In this embodiment, when the cleaning sheet passes through the fixing device 27 for the first time (first surface fixing) and when the cleaning sheet passes the second time (second surface fixing), the fixing belt 100 is used as the target. The temperature is adjusted to 180 ° C., which is the temperature.

  Finally, the CPU 10 controls the paper discharge roller 35 to discharge the cleaning paper to the paper discharge tray 28 outside the apparatus (S109).

<Occurrence of pressure roller contamination in a low temperature environment>
When the sheet is passed through the fixing nip N, dirt such as paper dust and toner accumulates on the pressure roller 600 regardless of the environment where the image forming apparatus 1 is installed. The accumulated stain is eliminated by discharging to the surface of the recording material by double-sided printing or by discharging to the surface of the recording material by executing the above-described cleaning mode.

  Therefore, in the image forming apparatus 1 of the present embodiment, the CPU 10 counts the number of executions of the fixing process as will be described later (cleaning counter C (hereinafter referred to as counter C)). The CPU 10 and the counter C function as a counting unit. When the value of the counter C becomes equal to or larger than the predetermined value, the CPU 10 displays a display for prompting execution of the cleaning mode for cleaning the pressure roller 600 on the operation unit 180 (FIG. 9). That is, the operation unit 180 functions as a notification unit. When the cleaning mode is executed, the CPU 10 resets the value of the counter C (in this embodiment, C = 0).

  In this embodiment, every time a sheet passes through the fixing device 27, the count is incremented by one, and when the value of the counter C becomes 2000 or more, a display prompting execution of the cleaning mode is performed. These values are examples, and may be set as appropriate according to the configuration of the apparatus. For example, 0.1 may be added. Further, the addition value of the counter C each time a sheet passes through the fixing device 27 may be weighted according to the length of the sheet in the transport direction.

  Note that the count unit counts the number of executions of the fixing process even when the addition value of the counter C is incremented by 0.1 each time the sheet passes through the fixing device 27 or when the addition value is weighted. Suppose you are.

  Here, when the second side of double-sided printing is made in a high-temperature environment, the accumulated stain can be discharged by the image on the first side coming into contact with the pressure roller 600. For this reason, the CPU 10 sets the value of the counter C to 0 when the second side of double-sided printing is performed in a high-temperature environment. That is, it functions as a reset unit that resets the counter C. In this embodiment, the CPU 10 resets the value of the counter C when the second side of double-sided printing is passed once in a high-temperature environment (the number of executions of the duplex mode is one or more times).

  On the other hand, when double-sided printing is performed in a low temperature environment, the temperature of the pressure roller 600 is lower than that in a high temperature environment. Therefore, even if the image on the first side of double-sided printing comes into contact with the pressure roller 600, the melting point of the toner is not reached, and the dirt accumulated on the pressure roller 600 cannot be discharged sufficiently. That is, the cleaning effect by double-sided printing is small compared to a high temperature environment. Therefore, if the counter C is reset as the double-sided printing is performed in a low-temperature environment, the display that prompts the cleaning mode to be performed at the timing when the cleaning of the pressure roller 600 should be prompted is not displayed. That is, there is a possibility that the timing at which the operator performs cleaning is delayed. For this reason, the pressure roller 600 is not cleaned at an appropriate timing, and dirt is accumulated on the pressure roller 600 and may adhere to the recording material and become manifest as an image defect.

  Therefore, when the second side of the duplex printing is passed under a low temperature environment, the counter C is added without resetting the counter C.

  In this embodiment, the low temperature environment refers to a case where the temperature detected by the environment sensor TH2 provided in the image forming apparatus 1 is lower than a predetermined temperature. In the present embodiment, a case where the temperature detected by the environment sensor TH2 is less than 10 ° C. is defined as a low temperature environment. This is because when the image forming apparatus 1 is placed in a low temperature environment, the temperature of the pressure roller 600 is difficult to increase. That is, the environment sensor TH2 functions as a detection unit that indirectly detects the temperature of the pressure roller 600.

  In this embodiment, the high temperature environment refers to a case where the temperature detected by the environment sensor TH2 provided in the image forming apparatus 1 is equal to or higher than a predetermined temperature (10 ° C. or higher in this embodiment).

<Accumulation of cleaning counter according to environment>
Next, the integration of the cleaning counter C according to the environment will be described with reference to the flowchart shown in FIG. 10 and the block diagram shown in FIG. FIG. 10 is a flowchart regarding the integration of the counter. The control shown in the flowchart is performed by the CPU 10 functioning as an execution unit executing a control program stored in a built-in storage unit. As shown in FIG. 8, the CPU 10 is electrically connected to the image forming unit 200 and the fixing device 27, and controls the image forming operation and the fixing operation by the image forming unit 200. The CPU 10 is electrically connected to the operation unit 180. Further, the CPU 10 is electrically connected to the transport mechanism and controls the transport of the paper P. The CPU 10 is electrically connected to the environment sensor TH2. The CPU 10 is electrically connected to the counter C, and adds or resets the value of the counter C.

  When the CPU 10 receives an energization command (for example, turning on the power switch) of the image forming apparatus 1, the CPU 10 waits for an input of a print command after shifting to start-up control. Here, the print command is an execution command for image forming processing to the image forming unit 200. For example, a print start instruction input from the operation unit 180 or an external personal computer by the operator, or a copy start instruction input from the operation unit 180 by the operator. If the CPU 10 receives a print command while waiting for the print command to be input (S201), the process proceeds to S202. The CPU 10 acquires sheet information including information on the size of the paper P on which a toner image is to be formed in the print command, and printing conditions including information regarding single-sided printing or double-sided printing (S202).

  Specifically, the sheet information of the paper P on which the toner image is to be formed and the printing condition information in the print command are input from the operation unit 180 or an external personal computer as instructions by the operator. The sheet information may include information regarding the basis weight of the paper P and the type of sheet material.

  The CPU 10 acquires the value of the temperature detected by the environment sensor TH2 (S203).

  Specifically, the CPU 10 finishes the image formation corresponding to the first sheet P of the print command after the print command is input (more specifically, the image data corresponding to the first sheet P is changed). The temperature of the environment sensor TH2 is acquired until the exposure apparatus 22 completes exposure). For example, it may be immediately after the input of the print command, or when the execution of the image forming process corresponding to the print command is started (more specifically, when the exposure device 22 starts the exposure corresponding to the image data). It may be. In this embodiment, the environment sensor TH2 constantly measures the temperature inside the image forming apparatus 1, and the CPU 10 reads the detection result of the environment sensor TH2 in response to the input of a print command. The environment sensor TH2 may be configured to measure the temperature inside the image forming apparatus 1 at a necessary timing in response to an instruction from the CPU 10. Further, the CPU 10 may use the detection result detected by the environment sensor TH2 at a predetermined timing after the print command is input until the image formation corresponding to the first sheet P of the print command is completed.

  Then, the CPU 10 starts executing the job to which the print command is input (S204).

  The CPU 10 determines whether or not the paper P has passed through the fixing device 27 (S205). If the paper P has passed through the single sheet fixing device 27, the process proceeds to S206. The fixing device 27 is provided with a sensor (not shown) that detects the passage of the paper P on the downstream side of the fixing nip portion N in the recording material conveyance direction. In response to the detection of the passage of the paper P by the sensor, the CPU 10 proceeds to S206. The method for detecting the passage of the paper P is not limited to this. For example, the CPU 10 may determine the timing at which the sheet P passes the fixing device 27 based on the detection result of the upstream sensor in the conveyance direction of the sheet P from the fixing nip N and the conveyance speed of the sheet P.

  Based on the information acquired in S202, the CPU 10 determines whether or not the sheet P that has passed through the fixing device 27 is a sheet to be printed on both sides (S206).

  If the sheet is printed on one side (No at S206), the CPU 10 adds a predetermined value (+1 in this embodiment) to the counter C (S207). For this added value, for example, a table in which the sheet information and the integrated value are associated with each other in advance is stored in the storage unit, and the CPU 10 determines the integrated value by referring to the table based on the information acquired in S202. To do.

  On the other hand, in the case of duplex printing, the CPU 10 determines whether or not the temperature acquired in S203 is less than 10 ° C. (S208).

  Here, when the temperature value is less than 10 ° C., that is, in a low-temperature environment, the CPU 10 accumulates the counter C even in duplex printing (S209). On the other hand, when the temperature acquired in S202 is 10 ° C. or higher, the CPU 10 resets the counter C (that is, sets C = 0) (S210).

  The CPU 10 repeats the flow shown in S205 to S211 until the job corresponding to the print command is completed (S211). If the next job is submitted before the job submitted in S201 is completed, the CPU 10 may be configured to repeat the flow shown in S205 to S211 until the next job is completed.

  When the job is finished (S211 YES), the CPU 10 determines whether or not the pressure roller 600 needs to be cleaned based on the value of the cleaning counter C. That is, the CPU 10 determines whether or not the value of the counter C is 2000 or more (S212).

  In S212, when the value of the counter C is 2000 or more, the CPU 10 displays a display for prompting the cleaning of the pressure roller 600 on the display unit (notification unit) 180B (S213). The display content shown in FIG. 9 is an example, and the message is not limited to this. In the present embodiment, the CPU 10 is configured to notify the operator by displaying on the display unit 180B that it is time to clean the pressure roller 600. However, the notification method to the operator is not limited to this. Not limited to. For example, it may be configured to announce by sound or turn on a lamp.

  If the value of the counter C is less than 2000 in S212, the CPU 10 ends without displaying S213.

  In this embodiment, the CPU 10 obtains the value of the environment sensor TH2 before starting the job (S203). However, every time the paper P to be printed on both sides is conveyed to the fixing device 27 (that is, S208). The configuration may be such that the detection result by the environmental sensor TH2 is acquired.

  In the present embodiment, in S206, regardless of whether the first side or the second side of double-sided printing is used, it is determined that the double-sided printing is YES, but this is the second side of double-sided printing. It is good also as a structure determined as YES only in the case. That is, if it is single-sided printing or if it is the first side of double-sided printing, NO is determined in S206. As described above, the cleaning effect of the pressure roller 600 can be obtained in a high-temperature environment because the toner image on the first surface is in contact with the pressure roller 600 during the fixing process on the second surface in double-sided printing. .

  In this embodiment, the value of the counter C is updated every time one sheet P passes through the fixing device 27. However, after the job is finished (that is, between S211 and S212), It is good also as a structure which updates a value. Specifically, the CPU 10 adds a total value calculated from the number of sheets passed in the job to the counter C when there is no duplex printing. When there is duplex printing, the CPU 10 resets the counter C.

  In the present embodiment, the display for prompting cleaning is performed after the end of the job (S213). However, the display may be performed when the value of the counter C reaches 2000 during the job.

  As described above, when the temperature detected by the environment sensor TH2 is less than 10 ° C., the image forming apparatus 1 determines that the environment is a low temperature environment, and executes the counter C integration even during duplex printing. That is, in a low temperature environment, the image forming apparatus 1 performs integration without resetting the counter C, and displays a message that prompts the execution of the cleaning mode if the value of the counter C exceeds a predetermined value. The pressure roller 600 is cleaned according to the operator's instructions. As a result, the image forming apparatus 1 can perform notification that prompts the execution of cleaning at an appropriate timing even in a low-temperature environment, so that accumulation of dirt on the pressure roller 600 is suppressed, and an image defect becomes apparent. Can be suppressed.

[Example 2]
In the first embodiment, when the temperature detected by the environmental sensor TH2 which is a means for indirectly detecting the temperature of the pressure roller 600 is lower than a predetermined temperature, the CPU 10 has passed the double-sided printing paper P. Accordingly, the counter C is not reset.

  In the second embodiment, instead of the environmental sensor TH2, a counter associated with the passage of the double-sided printing paper P based on the temperature detected by the temperature sensor TH3 that directly detects the temperature of the pressure roller 600. It is determined whether or not C is reset.

  Since other configurations are the same as those in the first embodiment, members having the same functions as those described in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

<Integration of cleaning counter according to pressure roller temperature>
As described in the first embodiment, when the installation environment of the image forming apparatus 1 is low, the temperature of the surface of the pressure roller 600 becomes low. Is not fully exhaled. Therefore, in the image forming apparatus 1 of the present embodiment, the CPU 10 performs integration of the cleaning counter C based on the detection result of the temperature sensor TH3 that detects the surface temperature of the pressure roller 600.

  The integration of the cleaning counter according to the surface temperature of the pressure roller 600 will be described with reference to the flowchart shown in FIG. 11 and the block diagram shown in FIG. FIG. 11 is a flowchart regarding the integration of the counter. The control shown in the flowchart is performed by the CPU 10 functioning as an execution unit executing a control program stored in a built-in storage unit. As shown in FIG. 8, the CPU 10 is electrically connected to the image forming unit 200 and the fixing device 27, and controls the image forming operation and the fixing operation by the image forming unit 200. The CPU 10 is electrically connected to the operation unit 180. Further, the CPU 10 is electrically connected to the transport mechanism and controls the transport of the paper P. The CPU 10 is electrically connected to the temperature sensor TH3. The CPU 10 is electrically connected to the counter C, and adds or resets the value of the counter C.

  S301 and S302 are the same as S201 and S202 of FIG.

  The CPU 10 acquires the value of the temperature detected by the temperature sensor TH3 (S303).

  Specifically, the CPU 10 finishes the image formation corresponding to the first sheet P of the print command after the print command is input (more specifically, the image data corresponding to the first sheet P is changed). The temperature of the temperature sensor TH3 is acquired until the exposure apparatus 22 completes exposure). For example, it may be immediately after the input of the print command, or when the execution of the image forming process corresponding to the print command is started (more specifically, when the exposure device 22 starts the exposure corresponding to the image data). It may be. In this embodiment, the temperature sensor TH3 constantly measures the temperature of the pressure roller 600, and the CPU 10 reads the detection result of the temperature sensor TH3 in response to the input of a print command. The temperature sensor TH3 may be configured to measure the temperature of the pressure roller 600 at a necessary timing upon receiving an instruction from the CPU 10. Further, the CPU 10 may use the detection result detected by the temperature sensor TH3 at a predetermined timing from when the print command is input to when the image formation corresponding to the first sheet P of the print command is completed.

  S304 and S305 are the same as S204 and S205 in FIG.

  Based on the information acquired in S302, the CPU 10 determines whether or not the sheet P that has passed through the fixing device 27 is a sheet to be printed on both sides (S306).

  In the case of a sheet that is printed on one side (No in S306), the CPU 10 adds a predetermined value (+1 in this embodiment) to the counter C (S307). For this added value, for example, a table in which sheet information and integrated values are associated with each other in advance is stored in the storage means, and the CPU 10 determines the integrated value by referring to the table based on the information acquired in S302. To do.

  On the other hand, in the case of duplex printing, the CPU 10 determines whether or not the temperature acquired in S303 is less than a predetermined temperature (in this embodiment, less than 70 ° C.) (S308).

  Here, when the temperature value is less than 70 ° C., that is, when the pressure roller 600 is at a low temperature, the CPU 10 accumulates the counter C even in double-sided printing (S309). On the other hand, when the temperature acquired in S302 is 70 ° C. or higher, the CPU 10 resets the counter C (that is, sets C = 0) (S310).

  The CPU 10 repeats the flow shown in S305 to S311 until the job corresponding to the print command is completed (S311). If the next job is submitted before the job submitted in S301 is completed, the CPU 10 may be configured to repeat the flow shown in S305 to S311 until the next job is completed.

  When the job is finished (S311 YES), the CPU 10 determines whether or not the pressure roller 600 needs to be cleaned based on the value of the cleaning counter C. That is, the CPU 10 determines whether or not the value of the counter C is 2000 or more (S312).

  S312 and S313 are the same as S212 and S213 in FIG.

  In this embodiment, the CPU 10 acquires the value of the temperature sensor TH3 before the start of the job (S303). However, every time the sheet P to be printed on both sides is conveyed to the fixing device 27 (that is, S308). In this case, the detection result by the temperature sensor TH3 may be acquired.

  In the present embodiment, in S306, it is determined that YES is set for double-sided printing regardless of whether the first or second side of double-sided printing, but this is the second side of double-sided printing. It is good also as a structure determined as YES only in the case. That is, if it is single-sided printing or if it is the first side of double-sided printing, NO is determined in S306. As described above, the cleaning effect of the pressure roller 600 can be obtained in a high-temperature environment because the toner image on the first surface is in contact with the pressure roller 600 during the fixing process on the second surface in double-sided printing. .

  In this embodiment, the value of the counter C is updated every time one sheet P passes through the fixing device 27. However, after the job is finished (that is, between S311 and S312), It is good also as a structure which updates a value. Specifically, the CPU 10 adds a total value calculated from the number of sheets passed in the job to the counter C when there is no duplex printing. When there is duplex printing, the CPU 10 resets the counter C.

  In the present embodiment, the display for prompting cleaning is performed after the end of the job (S313). However, the display may be performed when the value of the counter C reaches 2000 during the job.

  As described above, when the temperature detected by the temperature sensor TH3 is less than 70 ° C., the image forming apparatus 1 determines that the pressure roller 600 is at a low temperature, and executes the counter C integration even during duplex printing. . That is, the image forming apparatus 1 performs integration without resetting the counter C when the pressure roller 600 is at a low temperature. Then, when the value of the counter C becomes equal to or greater than a predetermined value, the image forming apparatus 1 displays that the cleaning mode is urged and then performs the cleaning of the pressure roller 600 according to the operator's instruction. As a result, the image forming apparatus 1 can perform notification that prompts the execution of cleaning at an appropriate timing even when the pressure roller 600 is at a low temperature, thereby suppressing accumulation of dirt on the pressure roller 600. The occurrence of image defects can be suppressed.

Example 3
In the first and second embodiments, the counter C is set when the double-sided printing is executed once when the environment is a high temperature (Example 1) or when the pressure roller 600 is not low temperature (Example 2). It was set as the structure to reset.

  In the third embodiment, a configuration is described in which the counter C is reset when double-sided printing is performed a plurality of times (for example, five times or more) in a high temperature environment or when the pressure roller 600 is not at a low temperature. To do.

  Hereinafter, a case where the configuration in which the counter C is reset when the double-sided printing is passed a plurality of times (for example, five times or more) is applied to the first embodiment will be described as an example. That is, the CPU 10 will describe a configuration in which the counter C is reset in response to the double-sided printing that has been passed through a plurality of times (for example, five times or more) when the environmental sensor TH2 is equal to or higher than a predetermined temperature. . In addition, the same code | symbol is attached | subjected to the member which has the same function as the member demonstrated in Example 1, and the overlapping description is abbreviate | omitted.

<Reset counter>
In this embodiment, the image forming apparatus 1 includes a reset counter D that counts the number of times of duplex printing in addition to the above-described cleaning counter C (counter C) (FIG. 8). The CPU 10 clears (resets) the value of the counter C to 0 when the value of the reset counter D exceeds a predetermined value.

  In the present embodiment, the CPU 10 increments the reset counter D by one each time the sheet P to be printed on both sides passes through one fixing device 27. Then, the CPU (reset unit) 10 clears (resets) the value of the counter C to 0 when the value of the reset counter D becomes 5 or more. These values are examples, and may be set as appropriate according to the configuration of the apparatus. For example, 0.1 may be added. Further, the added value of the reset counter D may be weighted according to the length in the transport direction of the paper to be passed.

  Even when the addition value of the reset counter D is incremented by 0.1 each time the sheet passes through the fixing device 27 or when the addition value is weighted, the CPU 10 counts the number of times of duplex printing. Suppose you are.

<Accumulation of cleaning counter according to environment>
Next, the integration of the cleaning counter C according to the environment will be described with reference to the flowchart shown in FIG. 12 and the block diagram shown in FIG. FIG. 12 is a flowchart regarding the integration of the counter. The control shown in the flowchart is performed by the CPU 10 functioning as an execution unit executing a control program stored in a built-in storage unit. As shown in FIG. 8, the CPU 10 is electrically connected to the image forming unit 200 and the fixing device 27, and controls the image forming operation and the fixing operation by the image forming unit 200. The CPU 10 is electrically connected to the operation unit 180. Further, the CPU 10 is electrically connected to the transport mechanism and controls the transport of the paper P. The CPU 10 is electrically connected to the environment sensor TH2. The CPU 10 is electrically connected to the counter C and the reset counter D, and adds or resets the values of the counter C and the reset counter D.

  S401 to S405 are the same as S201 to S205 in FIG.

  Based on the information acquired in S402, the CPU 10 determines whether or not the sheet P that has passed through the fixing device 27 is a sheet to be printed on both sides (S406).

  If the sheet is a single-side printed sheet (No at S406), the CPU 10 adds a predetermined value (+1 in this embodiment) to the counter C (S407). For this added value, for example, a table in which the sheet information and the integrated value are associated with each other in advance is stored in the storage unit, and the CPU 10 determines the integrated value by referring to the table based on the information acquired in S402. To do.

  On the other hand, in the case of duplex printing, the CPU 10 determines whether or not the temperature acquired in S403 is less than 10 ° C. (S408).

  Here, when the temperature value is less than 10 ° C., that is, in a low-temperature environment, the CPU 10 accumulates the counter C even in double-sided printing (S409).

  On the other hand, when the temperature acquired in S402 is 10 ° C. or higher, the CPU 10 adds a predetermined value (+1 in this embodiment) to the reset counter D (S410). In S410, a predetermined value (+1 in this embodiment) may be added not only to the reset counter D but also to the counter C.

  In S411, the CPU 10 determines whether or not the reset counter D is greater than or equal to a predetermined value (5 or greater in this embodiment). When the reset counter D is less than the predetermined value (S411 No), the CPU 10 proceeds to S414. When the reset counter D is equal to or greater than the predetermined value (YES in S411), the CPU 10 resets the values of the counter C and the reset counter D (that is, C = 0 and D = 0) (S412 and S413).

  The CPU 10 repeats the flow shown in S405 to S414 until the job corresponding to the print command is completed (S414). If the next job is submitted before the job submitted in S401 is completed, the CPU 10 may repeat the flow shown in S405 to S414 until the next job is completed.

  When the job is finished (S414 YES), the CPU 10 determines whether or not the pressure roller 600 needs to be cleaned based on the value of the cleaning counter C. That is, the CPU 10 determines whether or not the value of the counter C is 2000 or more (S415).

  S415 and S416 are the same as S212 and S213 in FIG.

  In this embodiment, the CPU 10 acquires the value of the environment sensor TH2 before the start of the job (S403). However, every time the paper P to be printed on both sides is conveyed to the fixing device 27 (that is, S408). The configuration may be such that the detection result by the environmental sensor TH2 is acquired.

  In the present embodiment, in S406, it is determined to be YES in the case of double-sided printing regardless of whether the first side or the second side of double-sided printing, but this is the second side of double-sided printing. It is good also as a structure determined as YES only in the case. That is, if it is single-sided printing or if it is the first side of double-sided printing, NO is determined in S406. As described above, the cleaning effect of the pressure roller 600 can be obtained in a high-temperature environment because the toner image on the first surface is in contact with the pressure roller 600 during the fixing process on the second surface in double-sided printing. .

  In this embodiment, the value of the counter C is updated every time one sheet P passes through the fixing device 27. However, after the job is finished (that is, between S414 and S415), It is good also as a structure which updates a value. Specifically, when the value of the reset counter D is less than 5 sheets (that is, when the number of times of duplex printing in a high temperature environment is less than a predetermined value), the CPU 10 calculates the number of sheets passed in the job. Is added to the counter C. On the other hand, when the value of the reset counter D is 5 or more (that is, the number of executions of double-sided printing under a high temperature environment is a predetermined value or more), the CPU 10 resets the counter C and the reset counter D.

  In the present embodiment, the display for prompting cleaning is performed after the end of the job (S416). However, the display may be performed when the value of the counter C reaches 2000 during the job.

  As described above, when the temperature detected by the environment sensor TH2 is less than 10 ° C., the image forming apparatus 1 determines that the environment is a low temperature environment, and executes the counter C integration even during duplex printing. That is, in a low temperature environment, the image forming apparatus 1 performs integration without resetting the counter C, and displays a message that prompts the execution of the cleaning mode if the value of the counter C exceeds a predetermined value. The pressure roller 600 is cleaned according to the operator's instructions. As a result, the image forming apparatus 1 can perform notification that prompts the execution of cleaning at an appropriate timing even in a low-temperature environment, so that accumulation of dirt on the pressure roller 600 is suppressed, and an image defect becomes apparent. Can be suppressed.

  In the present embodiment, the configuration in which the counter C is reset when double-sided printing is performed a plurality of times (for example, five times or more) has been described as an example applied to the first embodiment. It may be applied to 2. That is, the CPU 10 responds to the fact that the double-sided printing executed when the detection result of the temperature sensor TH3 that detects the temperature of the pressure roller 600 is equal to or higher than a predetermined temperature has been performed a plurality of times (for example, five times or more). Thus, the counter C may be reset. In the description of this embodiment, the environmental sensor TH2 can be understood by replacing the temperature sensor TH3 with the temperature sensor TH3.

Example 4
In the above first to third embodiments, the CPU 10 is configured to add the value of the counter C every time the paper P is passed through the fixing device 27, but the counting method of the counter C is not limited to this.

  For example, the CPU 10 may be configured to decrease the value from the initial value (C = 2000) every time the paper P is passed through the fixing device 27. In this case, when the value of the counter C reaches a predetermined value (C = 0), the CPU 10 notifies that the cleaning mode is to be executed. In this case, the CPU 10 makes the number of double-sided printing performed in a high temperature environment (or when the pressure roller 600 is not low temperature) equal to or more than a predetermined value (for example, once in the first embodiment, for example, five times in the third embodiment). Accordingly, the value of the counter C is returned to the initial value (C = 2000). As a result, the CPU 10 resets the counter C.

Example 5
Further, the counter C adding method for prompting execution of the cleaning mode may be as follows.

  For example, every time the paper P is passed through the fixing device 27, the CPU 10 increments the value of the counter C from the initial value (C = 0), and the value of the counter C becomes equal to or greater than the threshold (C ≧ 2000). When this happens, a notification that prompts execution of the cleaning mode is made. After the cleaning mode is executed, the CPU 10 increments the count of the counter C when the cleaning mode is executed every time the paper P is passed through the fixing device 27. For example, when the cleaning mode is executed with C = 2000, the CPU 10 counts C = 2001, 2002,... Each time the paper P is passed through the fixing device 27, and C ≧ 4000. Then, a notification for urging the execution of the cleaning mode is performed again. That is, the operation unit 180 functions as a notification unit that performs notification for prompting the execution of the cleaning mode when the value counted by the count unit becomes equal to or greater than the threshold value.

  Further, the CPU 10 counts the counter C when the number of double-sided printing in the high temperature environment (or when the pressure roller 600 is not low temperature) reaches a predetermined value or more until 0 ≦ C <2000. The threshold value of is changed to a larger value. Specifically, when the initial threshold value is C = 2000 as described above and C = 500, the number of times duplex printing is performed in a high temperature environment (or when the pressure roller 600 is not low temperature) is equal to or greater than a predetermined value. Suppose that In this case, the CPU 10 sets the threshold value of the counter C for urging the execution of the cleaning mode as the number of executions of double-sided printing in a high temperature environment (or when the pressure roller 600 is not low) exceeds a predetermined value. = 2500. Thereafter, after the number of executions of double-sided printing in a high-temperature environment (or when the pressure roller 600 is not low-temperature) exceeds a predetermined value, the CPU 10 adds from the continuation, such as C = 501, 502,. To go. When the value of the counter C becomes C ≧ 2500, a display prompting execution of the cleaning mode is performed.

  That is, the CPU 10 executes duplex printing a predetermined number of times or more in a state where the temperature detected by the environmental sensor TH2 (or the temperature sensor TH3) is equal to or higher than a predetermined temperature until the value counted by the counting unit reaches the threshold value. If the threshold value is changed, the threshold value is changed to a new threshold value. That is, the CPU (changing unit) 10 substantially resets the counter C by changing the threshold value of the counter C for notifying the next execution of the cleaning mode to a value larger by a predetermined value.

  Also in the configuration of the present embodiment, the image forming apparatus 1 can perform notification that prompts the execution of cleaning at an appropriate timing, so that accumulation of dirt on the pressure roller 600 is suppressed and an image defect becomes obvious. Can be suppressed.

Example 6
In the fifth embodiment, the CPU 10 is configured to increment the value of the counter C from the initial value (C = 0) every time the paper P is passed through the fixing device 27. However, the CPU 10 The configuration may be such that the value is reduced from the initial value every time the sheet is passed through the fixing device 27.

  For example, every time the paper P is passed through the fixing device 27, the CPU 10 counts down the value of the counter C from the initial value (C = 10000), and the value of the counter C is equal to or less than the threshold (C ≦ 8000). When this happens, a notification that prompts execution of the cleaning mode is made. After the cleaning mode is executed, the CPU 10 counts down from the continuation of the counter C when the cleaning mode is executed each time the paper P is passed through the fixing device 27. For example, when the cleaning mode is executed with C = 8000, the CPU 10 counts C = 7999, 7998,... Every time the paper P is passed through the fixing device 27, and C ≦ 6000. Informing the user that the cleaning mode is to be executed. That is, the operation unit 180 functions as a notification unit that performs notification for prompting the execution of the cleaning mode when the value counted by the count unit becomes equal to or greater than the threshold value.

  Further, the CPU 10 executes the double-sided printing more than a predetermined value until 8000 <C ≦ 10000 (for example, once as in the first embodiment, and for example, five times as in the third embodiment). Accordingly, the threshold value of the counter C is changed to a smaller value. Specifically, when the initial threshold is C = 8000 as described above and C = 9500, the number of times of duplex printing in a high temperature environment (or when the pressure roller 600 is not low temperature) is equal to or greater than a predetermined value. Suppose that In this case, the CPU 10 sets the threshold value of the counter C for urging the execution of the cleaning mode as the number of executions of double-sided printing in a high temperature environment (or when the pressure roller 600 is not low) exceeds a predetermined value. = 7500 After that, the CPU 10 counts down from the continuation, such as C = 9499, 9498,... After the number of double-sided printing in the high temperature environment (or when the pressure roller 600 is not low temperature) reaches a predetermined value or more. . When the value of the counter C becomes C ≦ 7500, a display prompting execution of the cleaning mode is performed.

  That is, the CPU 10 executes duplex printing a predetermined number of times or more in a state where the temperature detected by the environmental sensor TH2 (or the temperature sensor TH3) is equal to or higher than a predetermined temperature until the value counted by the counting unit reaches the threshold value. If the threshold value is changed, the threshold value is changed to a new threshold value. That is, the CPU (changing unit) 10 substantially resets the counter C by changing the threshold value of the counter C for notifying the next execution of the cleaning mode to a value smaller by a predetermined value.

  Also in the configuration of the present embodiment, the image forming apparatus 1 can perform notification that prompts the execution of cleaning at an appropriate timing, so that accumulation of dirt on the pressure roller 600 is suppressed and an image defect becomes obvious. Can be suppressed.

1 Image forming apparatus 10 CPU
27 Fixing device 29 Reverse path 30 Double-sided path 100 Fixing rotating body 180 Operation unit 200 Image forming unit 600 Pressure rotating body C Cleaning counter P Paper TH2 Environment sensor TH3 Temperature sensor

Claims (20)

An image forming unit for forming an unfixed toner image on the recording paper;
A fixing rotator that is in contact with the surface of the recording paper having an unfixed toner image formed by the image forming unit, and a pressure rotator that forms a nip portion in cooperation with the fixing rotator, A fixing unit for fixing the toner image to the recording paper while nipping and conveying the recording paper at the nip portion;
A transport unit that reverses the front and back of the recording paper on which the toner image is fixed by the fixing unit and transports the recording paper again to the image forming unit and the fixing unit;
A predetermined toner image is formed on one side of the recording paper by the image forming unit, and this is fixed by the fixing unit. Then, the front and back sides of the recording paper are reversed by the conveying unit and supplied to the fixing unit. An execution unit for executing a cleaning mode for cleaning the pressure rotating body;
A detection unit for detecting the temperature of the pressure rotating body;
A counting unit that counts the number of executions of the fixing process to the recording paper by the fixing unit;
A notification unit for performing notification for urging the execution of the cleaning mode when the value counted by the count unit is equal to or greater than a predetermined value;
When the number of executions of the duplex mode in which the toner image is formed on both sides of the recording sheet executed in a state where the temperature detected by the detection unit is equal to or higher than a predetermined temperature becomes equal to or higher than a predetermined value, the count unit A reset unit for resetting the counted value;
An image forming apparatus comprising: A reception unit that receives an instruction to execute the cleaning mode from an operator,
The image forming apparatus according to claim 1, wherein the execution unit executes the cleaning mode in response to receiving the instruction by the reception unit. A heating unit for heating the fixing rotator,
3. The execution unit according to claim 1, wherein the execution unit conveys the recording paper to the fixing unit after the fixing rotating body is heated to a predetermined temperature by the heating unit in the execution of the cleaning mode. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 1, wherein the detection unit is a sensor that detects a surface temperature of the pressure rotator.   The image forming apparatus according to claim 1, wherein the detection unit is a sensor that detects an ambient temperature inside the image forming apparatus. An image forming unit for forming an unfixed toner image on the recording paper;
A fixing rotator that is in contact with the surface of the recording paper having an unfixed toner image formed by the image forming unit, and a pressure rotator that forms a nip portion in cooperation with the fixing rotator, A fixing unit for fixing the toner image to the recording paper while nipping and conveying the recording paper at the nip portion;
A transport unit that reverses the front and back of the recording paper on which the toner image is fixed by the fixing unit and transports the recording paper again to the image forming unit and the fixing unit;
A predetermined toner image is formed on one side of the recording paper by the image forming unit, and this is fixed by the fixing unit. Then, the front and back sides of the recording paper are reversed by the conveying unit and supplied to the fixing unit. An execution unit for executing a cleaning mode for cleaning the pressure rotating body;
A detection unit for detecting the temperature of the pressure rotating body;
A counting unit that counts the number of executions of the fixing process to the recording paper by the fixing unit;
A notification unit for performing notification for urging execution of the cleaning mode when the value counted by the count unit reaches a predetermined value;
When the number of executions of the duplex mode in which the toner image is formed on both sides of the recording sheet executed in a state where the temperature detected by the detection unit is equal to or higher than a predetermined temperature becomes equal to or higher than a predetermined value, the count unit A reset unit for resetting the counted value;
An image forming apparatus comprising: A reception unit that receives an instruction to execute the cleaning mode from an operator,
The image forming apparatus according to claim 6, wherein the execution unit executes the cleaning mode in response to receiving the instruction by the reception unit. A heating unit for heating the fixing rotator,
8. The execution unit according to claim 6, wherein the execution unit conveys the recording paper to the fixing unit after the fixing rotating body is heated to a predetermined temperature by the heating unit in the execution of the cleaning mode. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 6, wherein the detection unit is a sensor that detects a surface temperature of the pressure rotator.   The image forming apparatus according to claim 6, wherein the detection unit is a sensor that detects an ambient temperature inside the image forming apparatus. An image forming unit for forming an unfixed toner image on the recording paper;
A fixing rotator that is in contact with the surface of the recording paper having an unfixed toner image formed by the image forming unit, and a pressure rotator that forms a nip portion in cooperation with the fixing rotator, A fixing unit for fixing the toner image to the recording paper while nipping and conveying the recording paper at the nip portion;
A transport unit that reverses the front and back of the recording paper on which the toner image is fixed by the fixing unit and transports the recording paper again to the image forming unit and the fixing unit;
A predetermined toner image is formed on one side of the recording paper by the image forming unit, and this is fixed by the fixing unit. Then, the front and back sides of the recording paper are reversed by the conveying unit and supplied to the fixing unit. An execution unit for executing a cleaning mode for cleaning the pressure rotating body;
A detection unit for detecting the temperature of the pressure rotating body;
A counting unit that counts the number of executions of the fixing process to the recording paper by the fixing unit;
A notification unit for performing notification for urging the execution of the cleaning mode when the value counted by the count unit is equal to or greater than a threshold value;
The duplex mode in which the toner image is formed on both sides of the recording paper in a state where the temperature detected by the detection unit is equal to or higher than a predetermined temperature before the value counted by the count unit reaches the threshold is equal to or higher than a predetermined number of times. A change unit that, when executed, changes the value of the threshold to a value larger than the threshold by a predetermined value;
An image forming apparatus comprising: A reception unit that receives an instruction to execute the cleaning mode from an operator,
The image forming apparatus according to claim 11, wherein the execution unit executes the cleaning mode in response to receiving the instruction by the reception unit. A heating unit for heating the fixing rotator,
13. The execution unit according to claim 11, wherein, in the execution of the cleaning mode, the heating unit heats the fixing rotating body to a predetermined temperature and then transports the recording paper to the fixing unit. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 11, wherein the detection unit is a sensor that detects a surface temperature of the pressure rotator.   The image forming apparatus according to claim 11, wherein the detection unit is a sensor that detects an ambient temperature inside the image forming apparatus. An image forming unit for forming an unfixed toner image on the recording paper;
A fixing rotator that is in contact with the surface of the recording paper having an unfixed toner image formed by the image forming unit, and a pressure rotator that forms a nip portion in cooperation with the fixing rotator, A fixing unit for fixing the toner image to the recording paper while nipping and conveying the recording paper at the nip portion;
A transport unit that reverses the front and back of the recording paper on which the toner image is fixed by the fixing unit and transports the recording paper again to the image forming unit and the fixing unit;
A predetermined toner image is formed on one side of the recording paper by the image forming unit, and this is fixed by the fixing unit. Then, the front and back sides of the recording paper are reversed by the conveying unit and supplied to the fixing unit. An execution unit for executing a cleaning mode for cleaning the pressure rotating body;
A detection unit for detecting the temperature of the pressure rotating body;
A count unit for counting down the number of executions of the fixing process to the recording paper by the fixing unit;
A notification unit for performing notification for urging the execution of the cleaning mode when the value counted by the count unit is equal to or less than a threshold value;
The duplex mode in which the toner image is formed on both sides of the recording paper in a state where the temperature detected by the detection unit is equal to or higher than a predetermined temperature before the value counted by the count unit reaches the threshold is equal to or higher than a predetermined number of times. A change unit that, when executed, changes the value of the threshold to a value smaller than the threshold by a predetermined value;
An image forming apparatus comprising: A reception unit that receives an instruction to execute the cleaning mode from an operator,
The image forming apparatus according to claim 16, wherein the execution unit executes the cleaning mode in response to receiving the instruction by the reception unit. A heating unit for heating the fixing rotator,
18. The execution unit according to claim 16 or 17, wherein, in the execution of the cleaning mode, the recording unit is transported to the fixing unit after the fixing rotating body is heated to a predetermined temperature by the heating unit. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 16, wherein the detection unit is a sensor that detects a surface temperature of the pressure rotator. The image forming apparatus according to claim 16, wherein the detection unit is a sensor that detects an atmospheric temperature inside the image forming apparatus.

Images