Fixing device and image forming apparatus

Abstract

The invention provides a fixing device and an image forming apparatus. The fixing device includes: a fixing mechanism that performs pressure fixing while heating an image on a surface of a medium, the fixing mechanism having a base layer and a surface layer formed by covering a cylinder having a fold with the base layer, the surface layer having a thermal expansion coefficient different from that of the base layer; and a control mechanism that controls the fixing mechanism, and when a predetermined condition for deterioration of the crease is satisfied when the fixing operation is started, executes a crease elimination operation for extending the crease before the fixing operation is started.

Description

Technical Field

[0001] The present invention relates to a fixing device and an image forming device having the fixing device. Background Art

[0002] As for a fixing device for fixing an image by an image recording device, a technique described in Patent Document 1 listed below is conventionally known.

[0003] Patent Document 1 describes a structure in which a fixing member or a pressurizing member is covered with a fluororesin tube. The fluororesin tube of Patent Document 1 has folded irregularities formed during the manufacturing process, and the folded irregularities are smoothed by smoothing.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2001-109295 (

[0023] to

[0035] , Figure 3 ) Summary of the invention

[0005] The technical problem of the present invention is to suppress the degradation of image quality caused by creases in a fixing device using a fluororesin cylinder having creases as a surface layer, compared with the conventional technology which does not deal with creases that worsen after the operation of the image forming apparatus.

[0006] In order to solve the above technical problems, the fixing device of the invention according to claim 1 is characterized by comprising:

[0007] A fixing mechanism that heats an image on a medium surface and simultaneously performs pressure fixing, comprising a base layer and a cylinder having folds covered by the base layer and having a surface layer having a different thermal expansion coefficient from the base layer; and

[0008] The control means controls the fixing means, and when the fixing action is started, if a predetermined condition for worsening the crease is satisfied, performs a crease eliminating action for extending the crease before starting the fixing action.

[0009] The invention described in claim 2 is characterized in that, in the fixing device described in claim 1, it comprises:

[0010] The fixing mechanism includes a heating mechanism that is heated by a heat source and rotates, and a pressing mechanism that is arranged to face the heating mechanism and includes the base layer and the surface layer.

[0011] The invention described in claim 3 is characterized in that, in the fixing device described in claim 2, it comprises:

[0012] a core material; the base layer, which is arranged on the outer periphery of the core material and is composed of an elastic body; and the surface layer, which is composed of a fluororesin cylinder having the folds.

[0013] The invention described in claim 4 is characterized in that, in the fixing device described in any one of claims 1 to 3, it comprises:

[0014] The control means determines that the fold line worsening condition is satisfied when the operation time in the previous fixing operation reaches a predetermined first threshold value and the elapsed time from the end of the previous fixing operation is within a predetermined range.

[0015] The invention described in claim 5 is characterized in that, in the fixing device described in any one of claims 1 to 3, it comprises:

[0016] The control means determines that the fold line aggravation condition is satisfied when the temperature of the fixing means is within a predetermined range.

[0017] The invention described in claim 6 is characterized in that, in the fixing device described in any one of claims 1 to 5, it comprises:

[0018] The crease eliminating operation heats the fixing mechanism to a predetermined temperature.

[0019] The invention described in claim 7 is characterized in that, in the fixing device described in any one of claims 1 to 6, it includes:

[0020] The crease eliminating operation is performed in a state where the load applied to the crease is reduced compared to the fixing operation.

[0021] The invention described in claim 8 is characterized in that, in the fixing device described in claim 7, it comprises:

[0022] The crease eliminating operation reduces the pressure applied to the fixing mechanism compared to the fixing operation, thereby setting the load applied to the crease to a reduced state.

[0023] The invention described in claim 9 is characterized in that, in the fixing device described in claim 7, it comprises:

[0024] The crease eliminating operation is performed by rotating the fixing mechanism at a lower speed than during the fixing operation to thereby reduce the load applied to the crease.

[0025] In order to solve the above technical problems, the image forming apparatus of the invention according to claim 10 is characterized by comprising:

[0026] Image holding mechanism;

[0027] a transfer mechanism for transferring the image held on the image holding mechanism to a medium; and

[0028] The fixing device according to any one of aspects 1 to 9 fixes the image transferred to the medium.

[0029] Effects of the Invention

[0030] According to the first and tenth aspects of the present invention, in a fixing device using a fluororesin cylinder having folds as a surface layer, image quality degradation due to folds can be suppressed compared to the prior art which does not deal with folds that deteriorate after operation of the image forming apparatus.

[0031] According to the second aspect of the present invention, it is possible to suppress degradation of image quality due to folds of the pressurizing mechanism.

[0032] According to the third aspect of the present invention, it is possible to suppress degradation of image quality due to folds in the fluororesin surface layer.

[0033] According to the fourth aspect of the present invention, after the operation time reaches the first threshold and the temperature of the fixing mechanism is sufficiently increased, the crease eliminating operation can be executed when the elapsed time is such that the crease worsens. Therefore, unnecessary crease eliminating operation can be suppressed.

[0034] According to the fifth aspect of the present invention, the crease eliminating operation can be performed when the temperature of the fixing mechanism is within a predetermined range. Therefore, unnecessary crease eliminating operation can be suppressed.

[0035] According to the sixth aspect of the present invention, the fixing mechanism can be heated to thermally expand the base layer and the surface layer so as to extend the fold line.

[0036] According to the seventh aspect of the present invention, the life of the fixing device can be extended compared to a case where the load applied to the fold line is not reduced.

[0037] According to the eighth aspect of the present invention, the pressure applied to the fixing mechanism is reduced, so that the load applied to the fold line can be reduced.

[0038] According to the ninth aspect of the present invention, the rotation speed of the fixing mechanism is slowed down so that the load applied to the fold line can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0040] Figure 1 is an overall explanatory diagram of the image forming apparatus of Embodiment 1;

[0041] Figure 2 This is an explanatory diagram of the main parts of the image recording unit of Example 1;

[0042] Figure 3 is a cross-sectional view of a fixing mechanism of the fixing device of Example 1;

[0043] Figure 4 is a functional block diagram of the control unit of Example 1;

[0044] Figure 5 This is a flowchart of the control process of the fixing device in the first embodiment. DETAILED DESCRIPTION

[0045] Next, examples which are specific examples of the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples.

[0046] In addition, to facilitate understanding of the following description, in the accompanying drawings, the front-to-back direction is set as the X-axis direction, the left-to-right direction is set as the Y-axis direction, the up-down direction is set as the Z-axis direction, and the directions or sides indicated by the arrows X, -X, Y, -Y, Z, and -Z are set as front, rear, right, left, top, bottom, or front side, rear side, right side, left side, top side, and bottom side, respectively.

[0047] In the drawings, a mark with “·” in “○” means an arrow pointing from the back side to the front side of the paper, and a mark with “×” in “○” means an arrow pointing from the front side to the back side of the paper.

[0048] In the description using the following drawings, for easy understanding, illustration of components other than those necessary for the description is appropriately omitted.

[0049] [Example 1]

[0050] Figure 1 This is an overall explanatory diagram of the image forming apparatus of Embodiment 1.

[0051] exist Figure 1 In the embodiment 1, a copy machine U as an example of an image forming apparatus of the present invention includes a printing unit U1 as an example of an image recording mechanism and an example of an image recording device. A scanning unit U2 as an example of a reading mechanism and an example of an image reading device is supported on the top of the printing unit U1. An automatic document feeder U3 as an example of a document conveying device is supported on the top of the scanning unit U2.

[0052] A document tray TG1 as an example of a medium storage mechanism is arranged above the automatic document feeder U3. A plurality of documents Gi to be copied can be stacked and accommodated in the document tray TG1. A document discharge tray TG2 as an example of a document discharge unit is formed below the document tray TG1. Between the document tray TG1 and the document discharge tray TG2, a document conveying roller U3b is arranged along a document conveying path U3a.

[0053] A platen glass PG as an example of a transparent original table is arranged on the upper surface of the scanning unit U2. In the scanning unit U2 of Example 1, a reading unit U2a as an example of a reading unit is arranged below the platen glass PG. The reading unit U2a of Example 1 is supported movably in the left-right direction as an example of a sub-scanning direction along the lower surface of the platen glass PG. In addition, the reading unit U2a is electrically connected to the image processing unit GS.

[0054] Figure 2 This is a diagram for explaining the main parts of the image recording unit of the first embodiment.

[0055] The image processing unit GS is electrically connected to the writing circuit DL of the printing unit U1. The writing circuit DL is electrically connected to the exposure devices LHy, LHm, LHc, and LHk as an example of a latent image forming mechanism.

[0056] As an example, the exposure devices LHy to LHk of Example 1 are composed of an LED head in which a plurality of LEDs are arranged in the main scanning direction. The exposure devices LHy to LHk are configured to output writing lights corresponding to the respective colors of Y, M, C, and K according to the signals input from the writing circuit DL.

[0057] The writing circuit DL or the power supply circuit E controls the writing timing or the power supply timing based on a control signal from the control unit C as an example of control means.

[0058] exist Figure 1 In the embodiment, photosensitive bodies PRy, PRm, PRc, and PRk are arranged above the exposure devices LHy to LHk as an example of an image holding mechanism. Figure 1 , Figure 2 In FIG. 5 , the regions where the writing light is irradiated to the photoconductors PRy to PRk constitute writing regions Q1y, Q1m, Q1c, and Q1k.

[0059] Charging rollers CRy, CRm, CRc, and CRk are disposed as an example of charging means upstream of the writing areas Q1y to Q1k with respect to the rotation direction of the photoconductors PRy to PRk. The charging rollers CRy to CRk of the first embodiment are in contact with the photoconductors PRy to PRk and are supported so as to be driven and rotatable.

[0060] Developing devices Gy, Gm, Gc, and Gk are disposed downstream of writing areas Q1y to Q1k with respect to the rotation direction of the photoconductors PRy to PRk. Developing areas Q2y, Q2m, Q2c, and Q2k are formed by areas where the photoconductors PRy to PRk and the developing devices Gy to Gk face each other.

[0061] Primary transfer rollers T1y, T1m, T1c, and T1k are arranged downstream of the developing devices Gy to Gk with respect to the rotation direction of the photosensitive bodies PRy to PRk. Primary transfer areas Q3y, Q3m, Q3c, and Q3k are formed by areas where the photosensitive bodies PRy to PRk and the primary transfer rollers T1y to T1k face each other.

[0062] Photoconductor cleaners CLy, CLm, CLc, and CLk as an example of cleaning means are arranged downstream of the primary transfer rollers T1y to T1k with respect to the rotation direction of the photoconductors PRy to PRk.

[0063] On the downstream side of the photoconductor cleaners CLy to CLk with respect to the rotation direction of the photoconductor PRy to PRk, static eliminators Jy, Jm, Jc, and Jk are arranged as an example of static eliminator mechanism and an example of static eliminator device.

[0064] The Y-color photoreceptor PRy, charging roller CRy, exposure device LHy, developing device Gy, primary transfer roller T1y, photoreceptor cleaner CLy, and static eliminator Jy constitute an image generating unit Uy for Y color, which is an example of a formation mechanism for a Y-color visible image of Example 1 that forms a toner image for Y color. Similarly, the image generating units Um, Uc, and Uk for M, C, and K colors are constituted by the photoreceptors PRm, PRc, and PRk, charging rollers CRm, CRc, and CRk, exposure devices LHm, LHc, and LHk, developing devices Gm, Gc, and Gk, primary transfer rollers T1m, T1c, and T1k, photoreceptor cleaners CLm, CLc, and CLk, and static eliminators Jm, Jc, and Jk.

[0065] A belt module BM as an example of an intermediate transfer device is arranged above the photoconductors PRy to PRk. The belt module BM includes an intermediate transfer belt B as an example of an image holding mechanism and an example of an intermediate transfer mechanism. The intermediate transfer belt B is composed of an endless belt-shaped member.

[0066] The intermediate transfer belt B of the first embodiment is rotatably supported by a tension roller Rt as an example of a tensioning mechanism, a traveling roller Rw as an example of a deviation correction mechanism, an idle roller Rf as an example of a driven mechanism, a support roller T2a as an example of an opposing mechanism of a secondary transfer region, primary transfer rollers T1y to T1k, and a driving roller Rd as an example of a driving member. In the first embodiment, when the drive is transmitted to the driving roller Rd, the intermediate transfer belt B rotates.

[0067] A secondary transfer roller T2b as an example of a secondary transfer mechanism is arranged at a position opposing the support roller T2a across the intermediate transfer belt B. The support roller T2a and the secondary transfer roller T2b constitute the secondary transfer device T2 of the first embodiment as an example of a transfer device. The area where the secondary transfer roller T2b contacts the intermediate transfer belt B constitutes a secondary transfer area Q4.

[0068] A belt cleaner CLb is disposed as an example of a cleaning device for the intermediate transfer body on the downstream side of the secondary transfer region Q4 with respect to the rotation direction of the intermediate transfer belt B.

[0069] The primary transfer rollers T1y to T1k, the intermediate transfer belt B, and the secondary transfer device T2 constitute the transfer device T1+T2+B of the first embodiment as an example of a transfer mechanism. The image generating units Uy to Uk and the transfer device T1+T2+B constitute the image recording units Uy to Uk+T1+T2+B of the first embodiment.

[0070] exist Figure 1 In the embodiment, a pair of left and right guide rails GR as an example of a guide mechanism are provided below the image generating units Uy to Uk. On each guide rail GR, a paper feed tray TR1, TR2, TR3, and TR4 as an example of a medium storage mechanism are supported in a forward and backward direction. Recording paper S as an example of a medium is stored in the paper feed trays TR1 to TR4.

[0071] A pickup roller Rp as an example of a take-out mechanism is arranged at the upper left of the paper feed trays TR1 to TR4. A separation roller Rs as an example of a separation mechanism is arranged downstream of the pickup roller Rp with respect to the conveying direction of the recording paper S. A paper feed path SH1 extending upward is formed downstream of the separation roller Rs with respect to the conveying direction of the recording paper S as an example of a medium conveying path. A plurality of conveying rollers Ra as an example of a conveying mechanism are arranged on the paper feed path SH1.

[0072] A manual tray TR0 as an example of a medium storage mechanism is arranged at the lower left of the copy machine U. A pickup roller Rp0 is arranged at the upper right of the manual tray TR0, and a manual paper feed path SH0 extends. The manual paper feed path SH0 merges with the paper feed path SH1.

[0073] On the paper feeding path SH1, a registration roller Rr as an example of a conveyance timing adjustment mechanism is arranged upstream of the secondary transfer region Q4. A conveyance path SH2 extends from the registration roller Rr toward the secondary transfer region Q4.

[0074] A fixing device F is disposed downstream of the secondary transfer region Q4 with respect to the conveying direction of the recording paper S. The fixing device F includes a heating roller Fh as an example of a heating fixing mechanism and a pressure roller Fp as an example of a pressure fixing mechanism. The contact area between the heating roller Fh and the pressure roller Fp constitutes a fixing region Q5.

[0075] A lower paper discharge tray TRh as an example of a medium discharge unit is formed on the upper surface of the printing unit U1. In addition, in Embodiment 1, a binder (Finisher) U4 as an example of a post-processing device is provided on the lower paper discharge tray TRh. A paper discharge path SH3 as an example of a conveying path extends toward the lower paper discharge tray TRh above the fixing device F. A paper discharge roller Rh as an example of a medium conveying mechanism is arranged at the downstream end of the paper discharge path SH3.

[0076] An upper paper discharge tray TRh2 as an example of a medium discharge unit is arranged above the lower paper discharge tray TRh. An upper conveying path SH4 is formed above the fixing device F, branching from the paper discharge path SH3 and extending toward the upper paper discharge tray TRh2.

[0077] A reversing roller Rb as an example of a medium conveying mechanism is arranged on the upper conveying path SH4. A reversing path SH6 as an example of a medium conveying path branches from the upper conveying path SH4 to the lower left at a position above the branching position of the paper discharge path SH3 and the upper conveying path SH4.

[0078] A gate GT1 as an example of a switching mechanism is arranged in a form spanning a branch portion between the paper discharge path SH3 and the upper transport path SH4 and a branch portion between the upper transport path SH4 and the reversing path SH6. The gate GT1 is supported so as to be switchable between a first guide position (second position) for guiding the recording paper S from the fixing device F toward the lower paper discharge tray TRh and guiding the recording paper S from the upper transport path SH4 to the reversing path SH6 and a second guide position (first position) for guiding the recording paper S from the fixing device F to the upper transport path SH4.

[0079] A plurality of conveying rollers Ra are arranged on the reversing path SH6 as an example of a medium conveying mechanism. The downstream end of the reversing path SH6 merges with the paper feeding path SH1 on the upstream side of the registration rollers Rr.

[0080] (Description of Image Forming Operation)

[0081] In the copier U of the first embodiment having the above structure, when the operator manually places the original Gi on the platen glass PG and makes a copy, the reading unit U2a moves from the initial position in the left-right direction, and the original Gi on the platen glass PG is scanned while being exposed. In addition, when the automatic document feeder U3 is used to automatically transport the original Gi and make a copy, the plurality of originals Gi contained in the original tray TG1 are sequentially transported to the reading position of the original on the platen glass PG and pass through, and are discharged to the original paper discharge tray TG2. Each original Gi that passes through the reading position on the platen glass PG in turn is exposed and scanned by the reading unit U2a. In addition, the reading unit U2a receives the reflected light from the original Gi. The reading unit U2a converts the received reflected light of the original Gi into an electrical signal. In addition, when double-sided reading of the original Gi is performed, the original Gi is also read by the reading sensor.

[0082] The image processing unit GS inputs the electrical signal output from the reading unit U2a. The image processing unit GS converts the electrical signal of the image of R, G, B colors read by the reading unit U2a into image information of yellow (Y), magenta (M), cyan (C), and black (K) for latent image formation. The image processing unit GS outputs the converted image information to the writing circuit DL of the printing unit U1. In addition, when the image is a monochrome image, so-called monochrome, the image processing unit GS outputs only the image information of black K to the writing circuit DL.

[0083] The writing circuit DL outputs a control signal corresponding to the input image information to the exposure devices LHy to LHk. The exposure devices LHy to LHk output writing light corresponding to the control signal.

[0084] When image formation starts, each photoreceptor PRy to PRk is driven to rotate. A charging voltage is applied to the charging rollers CRy to CRk from the power supply circuit E. Therefore, the surface of the photoreceptors PRy to PRk is charged by the charging rollers CRy to CRk. In the writing area Q1y to Q1k, the charged photoreceptors PRy to PRk form an electrostatic latent image on the surface by the exposure devices LHy to LHk. In the developing area Q2y to Q2k, the electrostatic latent image of the photoreceptors PRy to PRk is developed into a toner image as an example of a visible image by the developing devices Gy to Gk.

[0085] The developed toner image is conveyed to the primary transfer area Q3y to Q3k in contact with the intermediate transfer belt B as an example of an intermediate transfer body. In the primary transfer area Q3y to Q3k, a primary transfer voltage having a polarity opposite to the charging polarity of the toner is applied to the primary transfer rollers T1y to T1k from the power supply circuit E. Therefore, the toner image on each photosensitive body PRy to PRk is transferred to the intermediate transfer belt B by the primary transfer rollers T1y to T1k. In addition, in the case of a multi-color toner image, the toner image on the downstream side is transferred to overlap the toner image transferred to the intermediate transfer belt B in the primary transfer area on the upstream side.

[0086] The photoreceptor cleaners CLy to CLk clean the residual and attached materials on the photoreceptors PRy to PRk after the primary transfer. The surfaces of the cleaned photoreceptors PRy to PRk are static-eliminated by static-eliminators Jy to Jk. The surfaces of the photoreceptors PRy to PRk after static-elimination are recharged by charging rollers CRy to CRk.

[0087] The monochromatic or multi-color toner images transferred onto the intermediate transfer belt B by the primary transfer rollers T1 y to T1 k in the primary transfer regions Q3 y to Q3 k are transported to the secondary transfer region Q4 .

[0088] The recording paper S with the image recorded on it is taken out by the pickup roller Rp of the paper feed tray TR1 to TR4 used. When a plurality of recording papers S are taken out overlapping, the recording papers S taken out by the pickup roller Rp are separated one by one by the separation roller Rs. The recording papers S separated by the separation roller Rs are conveyed on the paper feed path SH1 by the conveying roller Ra. The recording papers S conveyed on the paper feed path SH1 are conveyed to the registration roller Rr. The recording papers S accumulated on the manual tray TR0 are also conveyed to the paper feed path SH1 by the pickup roller Rp0 via the manual paper feed path SH0.

[0089] In conjunction with the timing at which the toner image formed on the intermediate transfer belt B is transported to the secondary transfer area Q4, the registration roller Rr transports the recording paper S to the secondary transfer area Q4. A secondary transfer voltage having a polarity opposite to the charging polarity of the toner is applied to the secondary transfer roller T2b via the power supply circuit E. Thus, the toner image on the intermediate transfer belt B is transferred from the intermediate transfer belt B to the recording paper S.

[0090] The intermediate transfer belt B after the secondary transfer is cleaned of the attached matter and the like on the surface by the belt cleaner CLb.

[0091] The recording paper S to which the toner image is secondarily transferred is heated and fixed when passing through the fixing area Q5 .

[0092] In the case of post-processing, the recording paper S with the image fixed thereon is conveyed to the binder U4 as an example of a post-processing device provided on the lower paper discharge tray TRh. In the case of not performing post-processing on the recording paper S, the recording paper S is conveyed to the upper paper discharge tray TRh2. In the case of conveying the recording paper S to the lower paper discharge tray TRh, the gate GT1 moves to the first guide position. Therefore, the recording paper S sent out from the fixing device F is conveyed on the paper discharge path SH3. The recording paper S conveyed on the paper discharge path SH3 is conveyed toward the binder U4 and the lower paper discharge tray TRh by the paper discharge roller Rh.

[0093] The stapler U4 performs a stapling process as an example of post-processing on the recording paper S, and then discharges the recording paper S to the lower paper discharge tray TRh.

[0094] When the recording paper S is discharged to the upper paper discharge tray TRh2 , the gate GT1 moves to the second guide position and the recording paper S is discharged to the upper paper discharge tray TRh2 .

[0095] When the recording paper S is printed on both sides, the gate GT1 moves to the second guide position. Then, when the rear end of the recording paper S passes through the gate GT1, the gate GT1 moves to the first guide position, and the reversing roller Rb rotates in the reverse direction. Therefore, the recording paper S is guided by the gate GT1 and sent to the reversing path SH6. The recording paper S transported on the reversing path SH6 is sent to the registration roller Rr in a state where the front and back sides are reversed.

[0096] (Description of the fixing device)

[0097] Figure 3 2 is a cross-sectional view of a fixing mechanism of the fixing device of Embodiment 1.

[0098] exist Figure 3 In the embodiment 1, the heating roller Fh as an example of the fixing mechanism and an example of the heating mechanism and the pressure roller Fp as an example of the fixing mechanism and an example of the pressure mechanism respectively have a core rod 1 as an example of the shaft portion and an example of the core material. An elastic layer 2 as an example of the base layer is formed on the outer periphery of the core rod 1. A release layer 3 as an example of the surface layer is laminated on the outer surface of the elastic layer 2. As an example, the release layer 3 of the embodiment 1 is composed of a fluororesin. In addition, the release layer 3 is preferably a fluororesin with good release properties for a toner or a recording paper S, but it is not limited thereto, and any release layer can be used.

[0099] The mold release layer 3 of Example 1 may be integrally formed on the surface of the elastic layer 2 , or the elastic layer 2 may be passed through the fluororesin cylinder and the mold release layer 3 may be laminated on the outer surface of the elastic layer 2 .

[0100] As described in Patent Document 1, a fluororesin tube may have folds formed in the manufacturing stage, and folds 3a may remain even after being laminated on the elastic layer 2. In addition, as described in Patent Document 1, folds 3a may be smoothed.

[0101] Furthermore, in Embodiment 1, the case where both the heating roller Fh and the pressure roller Fp have the same structure is exemplified, but the present invention is not limited thereto and either one may be configured using a fixing belt.

[0102] (Description of the Control Unit of Embodiment 1)

[0103] Figure 4 This is a functional block diagram of the control unit of Example 1.

[0104] exist Figure 4 In the embodiment 1, the control unit (controller) C as an example of the control mechanism of the copier U has an input / output interface I / O for inputting / outputting signals with the outside. In addition, the control unit C has a ROM: read-only memory storing programs and information for performing required processing. In addition, the control unit C has a RAM: random access memory for temporarily storing required data. In addition, the control unit C has a CPU: central processing unit that performs processing corresponding to the program stored in the ROM, etc. Thus, the control unit C of Example 1 is composed of a small information processing device, a so-called microcomputer. Therefore, the control unit C can realize various functions by executing the program stored in the ROM, etc.

[0105] The control unit C of the first embodiment receives a signal from the signal output element, and outputs a signal to the controlled element to perform control.

[0106] (Description of signal output requirements)

[0107] The control unit C receives input of signals from a user interface UI, a signal output element such as a sensor (not shown), and the like.

[0108] The user interface UI inputs the contents input by the user or operator to the control unit C. In the first embodiment, as an example, when a copy start as an example of a printing instruction is input on the user interface UI, a control signal is input to the control unit C.

[0109] (Explanation of controlled elements)

[0110] The control section C outputs signals to the power supply circuit E, the fixing control circuit D1, and other controlled elements (not shown).

[0111] The power supply circuit E controls power supply and the like for charging biases of charging rollers CRy to CRk, developing biases of developing devices Gy to Gk, primary transfer biases of primary transfer rollers T1y to T1k, and secondary transfer biases of secondary transfer roller T2b.

[0112] The fixing control circuit D1 controls the power supply to the heater F1, which is an example of a heating mechanism and an example of a heat source. Furthermore, the fixing control circuit D1 controls the driving of the fixing motor M1, which is an example of a fixing driving mechanism, to control the rotation of the pressure roller Fp. In addition, the structure is not limited to driving the pressure roller Fp, and may be set to a structure driving the heating roller Fh, or may be set to a structure driving both the heating roller Fh and the pressure roller Fp.

[0113] (Function of Control Unit C)

[0114] The control unit C of the first embodiment includes the following functional units (functional modules, program modules) C1 to C7.

[0115] The job control mechanism C1 controls jobs as image forming operations. When a copy start command is input or print data is input from an external information processing device, that is, when a job start command is issued, the job control mechanism C1 controls the power supply circuit E or a motor (not shown) to execute the job.

[0116] The printing time measuring mechanism C2 measures the printing time t1 as an example of the operation time. The printing time measuring mechanism C2 of the first embodiment starts measuring the printing time t1 when the job starts, and ends measuring the printing time t1 when the job ends.

[0117] The fixing device control mechanism C3 includes a fixing temperature control mechanism C3 a and a fixing pressure control mechanism C3 b , and controls the fixing device F via the fixing control circuit D1 .

[0118] The fixing temperature control mechanism C3a controls the on / off of the heater F1 via the fixing control circuit D1, thereby controlling the fixing temperature of the fixing area Q5. The fixing temperature control mechanism C3a controls the heater F1 so that the fixing temperature is within a predetermined range during the operation.

[0119] The fixing pressure control mechanism C3b controls the fixing pressure, which is the contact pressure between the heating roller Fh and the pressure roller Fp. The fixing pressure control mechanism C3b controls the fixing device F so that the fixing pressure becomes a predetermined fixing pressure during the operation.

[0120] The standby mode control mechanism C4, which is an example of a standby operation control mechanism, controls the operation of the copy machine U in the standby mode. In the first embodiment, after the job is completed, the copy machine U is transferred to the standby mode, which is an example of a standby operation, and waits until the next job is instructed to start. In the standby mode of the first embodiment, the heater F1 of the fixing device F is turned off. In addition, in the standby mode, the pressure of the fixing area Q5 is controlled to a standby pressure lower than the fixing pressure during the job.

[0121] The standby time measuring means C5 as an example of the standby time control means measures the standby time t2 as the duration of the standby mode. The standby time measuring means C5 of the first embodiment starts measuring the standby time t2 when the standby mode starts and ends measuring the standby time t2 when the standby mode ends.

[0122] The storage means C6 for fold deterioration conditions stores fold deterioration conditions as conditions for deterioration of the fold 3a. The storage means C6 for fold deterioration conditions of the first embodiment includes a storage means C6a for continuous printing time as an example of a first threshold storage means, a storage means C6b for a lower limit time elapsed as an example of a second threshold storage means, and a storage means C6c for an upper limit time elapsed as an example of a third threshold storage means.

[0123] The continuous printing time storage means C6a stores the continuous printing time ta as an example of the first threshold value. In the first embodiment, the continuous printing time ta is predetermined, and as an example, ta=30 minutes is set. The continuous printing time ta is not limited to the exemplified value, and can be set according to the printing time t1 at which the fold mark 3a is confirmed to be worsened by experiments.

[0124] The storage means C6b for the elapsed lower limit time stores the elapsed lower limit time tb1 as an example of the second threshold value. In the first embodiment, the elapsed lower limit time tb1 is predetermined, and as an example, tb1=30 minutes is set. The elapsed lower limit time tb1 is not limited to the exemplified value, and can be set according to the waiting time t2 at which the fold 3a begins to deteriorate confirmed by experiments or the like.

[0125] The storage means C6c for the elapsed upper limit time stores the elapsed upper limit time tb2 as an example of the third threshold value. In the first embodiment, the elapsed upper limit time tb2 is predetermined, and as an example, tb2=5 hours is set. The elapsed upper limit time tb2 is not limited to the value shown in the example, and can be set according to the waiting time t2 for the fold 3a to be eliminated confirmed by experiments or the like.

[0126] The crease elimination mode control mechanism C7 as an example of the crease elimination action control mechanism controls the execution of the crease elimination mode as the action of eliminating the crease 3a. The crease elimination mode control mechanism C7 of the first embodiment includes an execution determination mechanism C7a, an elimination temperature control mechanism C7b, an elimination pressure control mechanism C7c, an idling control mechanism C7d, an idling time measurement mechanism C7e, and an elimination mode end determination mechanism C7f.

[0127] The execution determination mechanism C7a determines whether to execute the crease elimination mode. The execution determination mechanism C7a of Example 1 determines that the crease elimination mode is executed when the crease deterioration condition is met when the fixing action is started. That is, when the job is instructed to start, the crease elimination mode is executed when the crease deterioration condition is met. In Example 1, when the printing time t1 reaches the continuous printing time ta, the standby time t2 reaches the elapsed lower limit time tb1, and the standby time t2 does not reach the elapsed upper limit time tb2, it is determined that the crease deterioration condition is met. That is, when the printing time t1, which is the operating time in the last fixing action, reaches the predetermined continuous printing time ta, and the standby time t2, which is the elapsed time from the end of the above-mentioned fixing action, is within a predetermined range (from the elapsed lower limit time tb1 to the elapsed upper limit time tb2), it is determined that the crease deterioration condition is met.

[0128] In the first embodiment, the execution of the crease elimination mode is determined using the printing time t1 or the standby time t2 which is a parameter related to the temperature of the elastic layer 2 or the release layer 3 of the heating roller Fh, etc., but the present invention is not limited thereto. For example, the temperature of the heating roller Fh, etc. may be measured by a temperature sensor, etc., and the crease elimination mode may be executed when the temperature of the heating roller Fh, etc. is within a predetermined temperature range. In addition, other parameters linked to the temperature of the heating roller Fh, etc., such as the power-on time or power consumption of the heater, the accumulated rotation speed of the motor, etc. may be used.

[0129] The erasing temperature control mechanism C7b controls the fixing temperature when the crease erasing mode is executed. In the first embodiment, when the crease erasing mode is started, the heater F1 is controlled via the fixing control circuit D1 so as to reach the fixing temperature when the operation is executed, that is, the erasing temperature. In addition, the erasing temperature is not limited to the same temperature as the fixing temperature, and can also be set to a temperature higher or lower than the fixing temperature according to the heat resistance temperature of each component, the target time until the crease is eliminated, etc. In addition, for example, since the higher the erasing temperature, the easier it is to eliminate the crease, it is preferably a high temperature.

[0130] The elimination pressure control mechanism C7c controls the fixing pressure when the crease elimination mode is executed. In Example 1, if the crease elimination mode is started, the fixing device F is controlled via the fixing control circuit D1 so that the elimination pressure becomes lower than the fixing pressure when the job is executed. In Example 1, the elimination pressure is set to the same pressure as the pressure in the standby mode, but it is not limited to this. The pressure can also be increased or decreased, or the fixing pressure can be set to zero, that is, the heating roller Fh is separated from the pressure roller Fp. In addition, for example, since the lower the fixing pressure, the smaller the load and stress applied to the crease 3a, the lower the pressure is preferably. However, in the case of separating the heating roller Fh from the pressure roller Fp, in the structure in which the pressure roller Fp is driven and the heating roller Fh is driven by the pressure roller Fp as in Example 1, the heating roller Fh cannot be rotated. Therefore, in the case of separation, it is desirable to set a structure in which both the heating roller Fh and the pressure roller Fp are driven, for example.

[0131] The idle control mechanism C7d controls the rotation of the heating roller Fh and the pressure roller Fp when the crease elimination mode is executed. In the first embodiment, when the crease elimination mode is started, the heating roller Fh and the pressure roller Fp are rotated via the fixing control circuit D1. That is, the heating roller Fh and the pressure roller Fp are rotated without performing the fixing operation of the developer, which is called idle rotation. In the case of idle rotation, it is preferable to suppress the temperature unevenness of the heating roller Fh, for example, compared with the case of non-idle rotation.

[0132] Furthermore, in the fold elimination mode of the first embodiment, the heating roller Fh and the like are rotated at a lower speed than the rotation speed during the operation. In the first embodiment, the rotation speed is set to a lower speed than during the operation, but it is not limited to this, and it may be set to a high speed or a low speed. In addition, for example, the lower the rotation speed, the smaller the load and stress applied to the fold 3a, so it is preferable.

[0133] The idle time measuring means C7e measures the idle time t3 as an example of the execution time of the crease mark elimination mode. The idle time measuring means C7e of the first embodiment starts measuring when the idle motion starts in the idle motion control means C7d, and ends measuring when the idle motion ends.

[0134] The elimination mode end determination mechanism C7f determines whether to end the crease elimination mode. When the idling time t3 reaches the predetermined elimination end time tc, the elimination mode end determination mechanism C7f of Example 1 determines that the crease elimination mode is ended. As an example, the elimination end time tc can be set to tc = 1 minute. In addition, the elimination end time tc is not limited to the time illustrated, and can be arbitrarily changed according to the design, specifications, etc. Moreover, the elimination end time tc is not limited to a fixed value. The elimination end time tc can also be set to a variable value, for example, the shorter the standby time t2, the shorter the elimination end time tc, or the higher the elimination temperature at the start of the crease elimination mode, the shorter the elimination end time tc, etc.

[0135] (Description of the flow chart)

[0136] Figure 5 This is a flowchart of the control process of the fixing device in the first embodiment.

[0137] Next, a control flow chart, a so-called flowchart, of the copy machine U according to the first embodiment will be described. However, only processes necessary for explaining the invention will be described in detail, and descriptions of other processes will be omitted.

[0138] Figure 5 The illustrated processing is executed in parallel with other processing of the copy machine U.

[0139] Figure 5 The processing is started by turning on the power of the copy machine U, that is, turning on the power.

[0140] exist Figure 5 In ST1 of the present invention, it is determined whether or not an instruction to start the operation has been given. If yes (Y), the process proceeds to ST2. If no (N), ST1 is repeated.

[0141] In ST2, it is determined whether the printing time t1 is greater than the continuous printing time ta. If yes (Y), the process proceeds to ST3. If no (N), the process proceeds to ST10.

[0142] In ST3, it is determined whether the waiting time t2 is greater than the elapsed lower limit time tb1. If yes (Y), the process proceeds to ST4. If no (N), the process proceeds to ST10.

[0143] In ST4, it is determined whether the waiting time t2 is less than the elapsed upper limit time tb2. If yes (Y), the process proceeds to ST5. If no (N), the process proceeds to ST10.

[0144] In ST5, the crease erasing mode is started to control the heater F1 so that the fixing temperature is raised to the erasing temperature. Then, the process proceeds to ST6.

[0145] In ST6, the fixing device F is controlled so that the fixing pressure is controlled to the canceling pressure. Then, the process proceeds to ST7.

[0146] In ST7, the next processing (1) and (2) are executed, and then the process proceeds to ST8.

[0147] (1) Start idling.

[0148] (2) Start measuring the idling time t3.

[0149] In ST8, it is determined whether the idle time t3 is equal to or longer than the elimination end time tc. If yes (Y), the process proceeds to ST9. If no (N), ST8 is repeated.

[0150] In setting ST9, the crease elimination mode is terminated. That is, the control of idling, temperature, and pressure is terminated. Then, the process proceeds to ST10.

[0151] In ST10, the next processing (1) and (2) are executed, and then the process proceeds to ST11.

[0152] (1) Execute the job.

[0153] (2) Start measuring the printing time t1.

[0154] In ST11, it is determined whether the operation is completed. If yes (Y), the process proceeds to ST12. If no (N), ST11 is repeated.

[0155] In ST12, the next processing (1) to (3) is executed, and then the process returns to ST1.

[0156] (1) The measurement of printing time t1 is completed.

[0157] (2) Start the standby mode. That is, reduce the fixing pressure and turn off the heater F1.

[0158] (3) Start measuring the standby time t2.

[0159] (Effect of Example 1)

[0160] In the copier U of the first embodiment having the above-described structure, when an instruction to start a job is given by inputting a copy start key or inputting print data from a personal computer, it is determined whether or not to execute the crease elimination mode. If the crease deterioration condition is satisfied, the crease elimination mode is executed. Then, after the crease elimination mode ends, the job is started. If the crease deterioration condition is not satisfied, the crease elimination mode is not executed (in the case of NO (N) in ST2 to ST4), and the job is started.

[0161] In Patent Document 1, in a structure in which a fluororesin cylinder having a crease is used as a surface layer, a crease smoothing process is performed at the stage before factory shipment before use in an image forming apparatus. Therefore, even if the crease worsens during use in the image forming apparatus, it cannot be dealt with. Here, in the heating roller Fh or the pressure roller Fp, the thermal expansion coefficients are different in the elastic layer 2 and the release layer 3, and generally, the thermal expansion coefficient of the elastic layer 2 is greater than that of the release layer 3. Therefore, during the operation, the elastic layer 2 is heated to the fixing temperature and thermally expands, and tension acts on the release layer 3 (so-called release layer 3 is stretched and stretched), and the crease 3a becomes inconspicuous. After the operation is completed, when the temperature of the heating roller Fh and the like gradually decreases, the thermal contraction of the elastic layer 2 increases, and the crease 3a becomes conspicuous and deepens. If the next operation is started in a state where the crease 3a is conspicuous, it is fixed before the release layer 3 is stretched in the first few sheets of printing after the operation starts. Therefore, there is a problem that the image quality is degraded due to the influence of the fold line 3 a , that is, horizontal streaks or so-called gloss lines are generated in the image along the fold line 3 a .

[0162] In contrast, in Example 1, when the conditions for the deterioration of the fold 3a are met, the fold elimination mode is executed. That is, before starting the operation, the heating roller Fh or the like is heated to thermally expand the elastic layer 2, and the release layer 3 is in a tensioned state so that the fold 3a is inconspicuous. Then, the operation is started in a state where the fold 3a is inconspicuous. Therefore, compared with the prior art described in Patent Document 1 which cannot deal with the deterioration of the fold after the image forming apparatus is operated, it is possible to suppress the degradation of image quality caused by the fold.

[0163] In addition, when the temperature of the heating roller Fh is still high just after the operation is completed, the thermal shrinkage of the fold 3a is still small, and the fold 3a is not noticeable. Therefore, when the next operation is started in this state, the adverse effect of the fold 3a is not easy to occur. Therefore, when the standby time t2 does not reach the lower limit time tb1, the thermal shrinkage is still small, the fold 3a is not noticeable, and it is judged that the adverse effect of the fold 3a is small, and the fold elimination mode is not executed. Therefore, compared with the case where the fold elimination mode is executed every time, the execution of unnecessary fold elimination mode is suppressed. Therefore, the reduction of productivity (the number of printed sheets per unit time) is suppressed.

[0164] Furthermore, if sufficient time has passed since the end of the operation, the thermal contraction of the release layer 3 is accompanied by the thermal contraction of the elastic layer 2, and the fold 3a becomes inconspicuous as in the initial state. Therefore, when the next operation is started in this state, the adverse effect of the fold 3a is less likely to occur. Therefore, when the standby time t2 reaches the upper limit time tb2, the fold 3a is inconspicuous because sufficient time has passed, and it is determined that the adverse effect of the fold 3a is small, and the fold elimination mode is not executed. Therefore, compared with the case where the fold elimination mode is executed every time, the execution of unnecessary fold elimination mode is suppressed. Therefore, the reduction in productivity (the number of printed sheets per unit time) is suppressed.

[0165] Furthermore, in Embodiment 1, the fixing pressure is reduced in the crease eliminating mode. Thus, the load applied to the crease 3a is reduced compared to the case where the fixing pressure is high. Thus, the life of the fixing device F is extended. Similarly, in Embodiment 1, the rotation speed of the heating roller Fh is set to a low speed in the crease eliminating mode. Thus, the load applied to the crease 3a is reduced compared to the case where the rotation speed is high. Therefore, the life of the fixing device F is extended.

[0166] (Change Example)

[0167] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments, and various modifications are possible within the scope of the gist of the present invention described in the claims. Modifications (H01) to (H02) of the present invention are shown below.

[0168] (H01) In the above embodiment, a copy machine U is illustrated as an example of an image forming apparatus, but the present invention is not limited thereto and may be constituted by, for example, a printer, a FAX (fax machine), or a multifunction machine having multiple or all of these functions. Furthermore, the present invention is not limited to an electrophotographic image forming apparatus and may be applied to any image forming apparatus such as an inkjet image forming apparatus or a thermal transfer image forming apparatus.

[0169] (H02) In the above embodiment, a structure using four-color developer is exemplified as the copy machine U, but the invention is not limited to this and can be applied to a monochrome image forming apparatus or a multi-color image forming apparatus with three or fewer colors or five or more colors.

[0170] (Note)

[0171] (((1)))A fixing device, characterized by comprising:

[0172] A fixing mechanism that heats an image on a medium surface and simultaneously performs pressure fixing, comprising a base layer and a cylinder having folds covered by the base layer and having a surface layer having a different thermal expansion coefficient from the base layer; and

[0173] The control means controls the fixing means, and when the fixing action is started, if a predetermined condition for worsening the crease is satisfied, performs a crease eliminating action for extending the crease before starting the fixing action.

[0174] (((2)))The fixing device according to (((1))) is characterized by comprising:

[0175] The fixing mechanism includes a heating mechanism that is heated by a heat source and rotates, and a pressing mechanism that is arranged to face the heating mechanism and includes the base layer and the surface layer.

[0176] (((3)))The fixing device according to (((2))) is characterized by comprising:

[0177] a core material; the base layer, which is arranged on the outer periphery of the core material and is composed of an elastic body; and the surface layer, which is composed of a fluororesin cylinder having the folds.

[0178] (((4))) The fixing device according to any one of (((1))) to (((3))), characterized by comprising:

[0179] The control means determines that the fold line worsening condition is satisfied when the operation time in the previous fixing operation reaches a predetermined first threshold value and the elapsed time from the end of the previous fixing operation is within a predetermined range.

[0180] (((5))) The fixing device according to any one of (((1))) to (((3))), characterized by comprising:

[0181] The control means determines that the fold line aggravation condition is satisfied when the temperature of the fixing means is within a predetermined range.

[0182] (((6))) The fixing device according to any one of (((1))) to (((5))), characterized by comprising:

[0183] The crease eliminating operation heats the fixing mechanism to a predetermined temperature.

[0184] (((7))) The fixing device according to any one of (((1))) to (((6))), characterized by comprising:

[0185] The crease eliminating operation is performed in a state where the load applied to the crease is reduced compared to the fixing operation.

[0186] (((8)))The fixing device according to (((7))) is characterized by comprising:

[0187] The crease eliminating operation reduces the pressure applied to the fixing mechanism compared to the fixing operation, thereby setting the load applied to the crease to a reduced state.

[0188] (((9)))The fixing device according to (((7))) is characterized by comprising:

[0189] The crease eliminating operation is performed by rotating the fixing mechanism at a lower speed than during the fixing operation to thereby reduce the load applied to the crease.

[0190] (((10)))An image forming apparatus, comprising:

[0191] Image holding mechanism;

[0192] a transfer mechanism for transferring the image held on the image holding mechanism to a medium; and

[0193] The fixing device according to any one of (((1))) to (((9))) fixes the image transferred to the medium.

[0194] According to the fixing device of (((1))), in a fixing device using a fluororesin cylinder having folds as a surface layer, image quality degradation due to folds can be suppressed compared to the prior art which does not deal with folds that deteriorate after operation of an image forming apparatus.

[0195] According to the fixing device according to (((2))), it is possible to suppress degradation of image quality due to folds of the pressure mechanism.

[0196] According to the fixing device according to (((3))), it is possible to suppress the degradation of image quality due to folds in the fluororesin surface layer.

[0197] According to the fixing device of (((4))), after the operation time reaches the first threshold and the fixing mechanism is sufficiently heated, the crease eliminating operation can be performed when the elapsed time is such that the crease worsens. Therefore, unnecessary crease eliminating operation can be suppressed.

[0198] According to the fixing device of (((5))), the crease eliminating operation can be performed when the temperature of the fixing mechanism is within a predetermined range. Therefore, unnecessary crease eliminating operation can be suppressed.

[0199] According to the fixing device according to (((6))), the fixing mechanism can be heated to thermally expand the base layer and the surface layer so as to extend the fold line.

[0200] According to the fixing device according to (((7))), the life of the fixing device can be extended compared to a case where the load applied to the fold line is not reduced.

[0201] According to the fixing device of (((8))), the pressure applied to the fixing mechanism is reduced, so that the load applied to the fold line can be reduced.

[0202] According to the fixing device according to (((9))), the rotation speed of the fixing mechanism is slowed down so that the load applied to the fold line can be reduced.

[0203] According to the fixing device involved in (((10))), in a fixing device using a fluororesin cylinder having folds as a surface layer, the image quality degradation caused by folds can be suppressed compared with the conventional technology which does not deal with folds that deteriorate after the image forming apparatus is operated.

[0204] The above-mentioned embodiments of the present invention are provided for the purpose of illustration and description. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed methods. Obviously, various modifications and changes are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily understand the principles of the present invention and its application. Thus, other technicians in the art can understand the present invention through various variations optimized for specific uses assumed to be various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

[0205] Explanation of symbols

[0206] 1-core material, 2-elastic layer, 3-surface layer, 3a-crease, C-control mechanism, F-fixing device, F1-heat source, Fh-heating mechanism, Fh, Fp-fixing mechanism, Fp-pressurizing mechanism, PRy, PRm, PRc, PRk-image holding mechanism, S-media, t1-operating time, T1+T2+B-transfer mechanism, t2-elapsed time from the end of the fixing action, ta-first threshold value, tb1-lower limit time, tb2-upper limit time, U-image forming device.

Claims

1. A fixing device, characterized in that: have: A fixing mechanism that heats the image on the surface of the medium and performs pressure fixing, comprising a base layer and a cylinder having folds covered by the base layer and having a surface layer with a different thermal expansion coefficient from the base layer; and The control means controls the fixing means, and when the fixing action is started, if a predetermined condition for worsening the crease is satisfied, performs a crease eliminating action for extending the crease before starting the fixing action.

2. The fixing device according to claim 1, characterized in that: have: The fixing mechanism includes a heating mechanism that is heated by a heat source and rotates, and a pressing mechanism that is arranged to face the heating mechanism and includes the base layer and the surface layer.

3. The fixing device according to claim 2, characterized in that: have: a core material; the base layer, which is arranged on the outer periphery of the core material and is composed of an elastic body; and the surface layer, which is composed of a fluororesin cylinder having the folds.

4. The fixing device according to any one of claims 1 to 3, characterized in that: have: The control means determines that the fold line worsening condition is satisfied when the operation time in the previous fixing operation reaches a predetermined first threshold value and the elapsed time from the end of the previous fixing operation is within a predetermined range.

5. The fixing device according to any one of claims 1 to 3, characterized in that: have: The control means determines that the fold line aggravation condition is satisfied when the temperature of the fixing means is within a predetermined range.

6. The fixing device according to any one of claims 1 to 5, characterized in that: have: The crease eliminating operation heats the fixing mechanism to a predetermined temperature.

7. The fixing device according to any one of claims 1 to 6, characterized in that: have: The crease eliminating operation is performed in a state where the load applied to the crease is reduced compared to the fixing operation.

8. The fixing device according to claim 7, characterized in that: have: The crease eliminating operation reduces the pressure applied to the fixing mechanism compared to the fixing operation, thereby setting the load applied to the crease to a reduced state.

9. The fixing device according to claim 7, characterized in that: have: The crease eliminating operation is performed by rotating the fixing mechanism at a lower speed than during the fixing operation to thereby reduce the load applied to the crease.

10. An image forming device, characterized in that: have: Image holding mechanism; a transfer mechanism for transferring the image held on the image holding mechanism to a medium; and The fixing device according to any one of claims 1 to 9, which fixes the image transferred to the medium.

Images