Fixing device and image forming apparatus

Abstract

To provide a fixing device and an image forming apparatus that can prevent an increase in the number of components, compared with the case of providing a special member for cleaning contact means that is in contact with heating means.SOLUTION: A fixing device F comprises: a heating roll Fh that heats a recording sheet S in contact therewith; and a conditioning roll 1 as an example of contact means that is not in contact with the recording sheet S and in contact with the heating roll Fh. The fixing device increases a surface temperature of the conditioning roll 1 compared with a surface temperature of the heating roll Fh to move an attachment from the conditioning roll 1 to the heating roll Fh.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] 2. Description of the Related Art In image forming apparatuses such as copiers, printers, and FAX machines, the technique described in Patent Document 1 below is known as a technique for adjusting the condition of a surface by bringing a member into contact with the surface of a heating means of a fixing device.

[0003] Japanese Patent Application Publication No. 2020-67466 (Patent Document 1) describes a technology in which a refreshing member (104) is arranged on the surface of the fixing roller (51) so that it can be brought into contact with and separated from the surface of the fixing roller (51), and the refreshing member (104) is pressed against the fixing roller (51) at a frequency determined according to the type of recording material. By rotating the fixing roller (51), the surface of the fixing roller (51) is rubbed with the refreshing member (104), thereby alleviating a condition in which the surface of the fixing roller (51) becomes locally rough, and reducing gloss streaks (image defects, fixing failures). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-67466 A ("0040", Figure 3) Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has a technical object to suppress an increase in the number of parts compared to a case where a dedicated member is provided for cleaning the contact means that comes into contact with the heating means. [Means for solving the problem]

[0006] In order to solve the above technical problem, the fixing device of the invention described in claim 1 comprises: A heating means for contacting and heating the medium; a contact means that does not contact the medium and that contacts the heating means; a pressure applying means disposed opposite to the heating means and in contact with the medium to apply pressure to the medium; a cleaning means for cleaning deposits on a surface of the pressing means by contacting the pressing means without contacting the medium; Equipped with The surface temperature of the contact means is made higher than the surface temperature of the heating means, and the deposit is moved from the contact means to the heating means. Along with The deposits transferred from the contact means to the heating means are transferred to the surface of the pressing means and then removed by the cleaning means. It is characterized by:

[0007] The invention described in claim 2 is the fixing device described in claim 1, After the surface temperature of the contact means becomes higher than the surface temperature of the heating means, the pressure means is brought into contact with the heating means. It is characterized by:

[0008] In order to solve the above technical problem, the fixing device of the invention described in claim 3 comprises: A heating means for contacting and heating the medium; a contact means that does not contact the medium and that contacts the heating means; Equipped with The heating means is cooled to make the surface temperature of the contact means higher than the surface temperature of the heating means, thereby transferring the deposits from the contact means to the heating means. It is characterized by:

[0009] The invention described in claim 4 is the fixing device described in claim 3, The heating means is cooled by bringing a medium into contact with the heating means. It is characterized by:

[0010] The invention described in claim 5 is the fixing device described in claim 3, a pressure applying means arranged opposite to the heating means and in contact with the medium to apply pressure to the medium; The pressure means is brought into contact with the heating means to cool the heating means, thereby making the surface temperature of the contact means higher than the surface temperature of the heating means. It is characterized by:

[0011] In order to solve the above technical problem, a fixing device according to the invention described in claim 6 comprises: A heating means for contacting and heating the medium; a contact means that does not contact the medium and that contacts the heating means; Equipped with The contact means and the heating means are separated to lower the temperature of the heating means, and then the contact means and the heating means are brought into contact with each other, thereby making the surface temperature of the contact means higher than the surface temperature of the heating means, and transferring the deposits from the contact means to the heating means. It is characterized by:

[0012] The invention described in claim 7 is the fixing device described in claim 6, Before the contact means and the heating means are separated, the contact means is brought into contact with the heated heating means to increase the surface temperature of the contact means. It is characterized by:

[0014] In order to solve the above technical problem, Claim 8 The image forming apparatus of the present invention is An image holding means; a transfer means for transferring the image on the surface of the image holding means to a medium; The image transferred to the medium is fixed according to any one of claims 1 to 5. 7 a fixing device according to any one of the preceding claims; The present invention is characterized by comprising: Effect of the Invention

[0015] Claim 1 According to the invention described in the above, an increase in the number of parts can be suppressed compared to a case in which a dedicated member is provided for cleaning the contact means that comes into contact with the heating means. According to the invention as recited in claim 1, the cleaning means for the contact means can also serve as the cleaning means for the pressure means. According to the invention described in claim 2, the surface temperature can be adjusted in the order of the contact means, the heating means, and the pressure means, and adhering substances such as developer can be transferred in the order of the contact means, the heating means, and the pressure means.

[0016] According to the invention described in claim 3, it is possible to suppress an increase in the number of parts compared to a case where a dedicated member is provided for cleaning the contact means that comes into contact with the heating means. According to the invention described in the above, the heating means can be cooled to create a temperature difference with the contact means. Claim 4 According to the invention described in the above, the medium can absorb heat by contacting the heating means, thereby cooling the heating means. Claim 5 According to the invention described in the above, the pressurizing means can absorb heat by contacting with the heating means, thereby cooling the heating means.

[0017] According to the invention described in claim 6, it is possible to suppress an increase in the number of parts compared to a case where a dedicated member is provided for cleaning the contact means that comes into contact with the heating means. According to the invention described in the above, by lowering the temperature of the heating means while the contact means is separated, it is possible to eliminate the link between the temperature drop of the heating means and the temperature drop of the contact means. Claim 7 According to the invention described in the above, the contact means can be heated by the heating means that fixes the image on the medium, and therefore there is no need to add a dedicated component for heating the contact means.

[0018] Claim 8According to the invention described in , an increase in the number of parts can be suppressed compared to a case where a dedicated member is provided for cleaning the contact means that comes into contact with the heating means. Claim 8 According to the invention described in claims 1 to 7 The present invention also has the effect of any one of the above. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is an overall explanatory diagram of an image forming apparatus according to a first embodiment. [Diagram 2] FIG. 2 is an enlarged explanatory view of the visible image forming device of the first embodiment. [Diagram 3] FIG. 3 is an enlarged view of the fixing device of the first embodiment. [Figure 4] FIG. 4 is an explanatory diagram of the control unit according to the first embodiment. [Diagram 5] FIG. 5 is an explanatory diagram of a flowchart of the cleaning process in the first embodiment. [Figure 6] FIG. 6 is an explanatory diagram of temperature changes of the heating roll and the conditioning roll during the cleaning operation in the first embodiment. [Figure 7] FIG. 7 is an explanatory diagram of a fixing device according to the second embodiment, and corresponds to FIG. 3 of the first embodiment. [Figure 8] FIG. 8 is an explanatory diagram of a control unit according to the second embodiment, and corresponds to FIG. 4 of the first embodiment. [Figure 9] FIG. 9 is an explanatory diagram of a flowchart of the cleaning process according to the second embodiment, and corresponds to FIG. 5 of the first embodiment. [Figure 10] FIG. 10 is an explanatory diagram of temperature changes of the heating roll, the conditioning roll, and the pressure roll during the cleaning operation in the second embodiment, and corresponds to FIG. 6 in the first embodiment. [Figure 11] FIG. 11 is an explanatory diagram of temperature changes of the heating roll, the conditioning roll, and the pressure roll during the cleaning operation in a modified example of the second embodiment, and corresponds to FIG. 6 in the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Next, specific examples of the present invention (hereinafter, referred to as examples) will be described with reference to the drawings, but the present invention is not limited to the following examples. In order to make the following explanation easier to understand, in the drawings, the front-to-back direction is the X-axis direction, the left-to-right direction is the Y-axis direction, and the up-down direction is the Z-axis direction, and the directions or sides indicated by arrows X, -X, Y, -Y, Z, and -Z are respectively the front, rear, right, left, upper, and lower, or the front side, rear side, right side, left side, upper side, and lower side. In addition, in the figures, a "·" inside a "○" means an arrow going from the back to the front of the page, and an "×" inside a "○" means an arrow going from the front to the back of the page. In the following description using the drawings, illustrations of components other than those necessary for the description are omitted as appropriate to facilitate understanding. EXAMPLES

[0021] FIG. 1 is an overall explanatory diagram of an image forming apparatus according to a first embodiment. FIG. 2 is an enlarged explanatory view of the visible image forming device of the first embodiment. In Figure 1, a copier U as an example of an image forming device has a user interface UI as an example of an operation unit, a scanner unit U1 as an example of an image reading device, a feeder unit U2 as an example of a media supply device, an image creating unit U3 as an example of an image recording device, and a media processing device U4.

[0022] (User Interface UI Description) The user interface UI has an input button UIa used to start copying, set the number of copies, etc. The user interface UI also has a display unit UIb on which the contents input by the input button UIa and the status of the copier U are displayed.

[0023] (Explanation of Feeder Section U2) 1, the feeder unit U2 has a plurality of paper feed trays TR1, TR2, TR3, and TR4 as an example of a medium storage container. The feeder unit U2 also has a medium supply path SH1 that takes out recording paper S as an example of an image recording medium stored in each of the paper feed trays TR1 to TR4 and transports it to the imaging unit U3.

[0024] (Explanation of the imaging unit U3 and media processing device U4) In FIG. 1, the image forming unit U3 has an image recording unit U3a that records an image on the recording paper S conveyed from the feeder unit U2 based on an original image read by the scanner unit U1. 1 and 2, a driving circuit D of the latent image forming device of the imaging unit U3 outputs corresponding driving signals at preset times to the latent image forming devices ROSy, ROSm, ROSc, and ROSk of each color Y to K based on image information input from the scanner unit U1. Photoconductor drums Py, Pm, Pc, and Pk as an example of an image holding means are arranged below each of the latent image forming devices ROSy to ROSk as an example of a writing means.

[0025] The surfaces of the rotating photoconductor drums Py, Pm, Pc, and Pk are uniformly charged by charging rolls CRy, CRm, CRc, and CRk, respectively, which are an example of a charging means. Electrostatic latent images are formed on the charged surfaces of the photoconductor drums Py to Pk by laser beams Ly, Lm, Lc, and Lk, which are an example of latent image writing light outputted from latent image forming devices ROSy, ROSm, ROSc, and ROSk. The electrostatic latent images on the surfaces of the photoconductor drums Py, Pm, Pc, and Pk are developed into toner images, which are an example of visible images, of yellow (Y), magenta (M), cyan (C), and black (K), by developing devices Gy, Gm, Gc, and Gk, which are an example of a developing means. In the developing devices Gy to Gk, the developer consumed by development is replenished from toner cartridges Ky, Km, Kc, and Kk, which are an example of a developer storage means. The toner cartridges Ky, Km, Kc, and Kk are detachably mounted in the developer replenishing device U3b.

[0026] The toner images on the surfaces of the photoconductor drums Py, Pm, Pc, and Pk are transferred in a superimposed manner in primary transfer areas Q3y, Q3m, Q3c, and Q3k onto an intermediate transfer belt B, an example of an intermediate transfer means, by primary transfer rolls T1y, T1m, T1c, and T1k, an example of a transfer means and an example of a primary transfer device, to form a color toner image, an example of a multi-color visible image, on the intermediate transfer belt B. The color toner image formed on the intermediate transfer belt B is transported to a secondary transfer area Q4. When only K-color image information is recorded, only the K-color photoconductor drum Pk and the developing device Gk are used, and only the K-color toner image is formed. After the primary transfer, residual developer, paper powder, and other residues adhering to the surfaces of the photosensitive drums Py, Pm, Pc, and Pk are removed by drum cleaners CLy, CLm, CLc, and CLk, which are an example of a cleaning means for an image holding means.

[0027] In the first embodiment, the photoconductor drum Pk, the charging roll CRk, and the drum cleaner CLk are integrated as a photoconductor unit UK for the color K, which is an example of an image carrier unit. Similarly, for the other colors Y, M, and C, the photoconductor drums Py, Pm, and Pc, the charging rolls CRy, CRm, and CRc, and the drum cleaners CLy, CLm, and CLc constitute photoconductor units UY, UM, and UC. Further, the K-color visible image forming device UK+Gk is configured by the K-color photoconductor unit UK and the developing device Gk having the developing roll R0k as an example of a developer holding means. Similarly, the Y-, M-, and C-color visible image forming devices UY+Gy, UM+Gm, and UC+Gc are configured by the Y-, M-, and C-color photoconductor units UY, UM, and UC and the developing devices Gy, Gm, and Gc having the developing rolls R0y, R0m, and R0c, respectively.

[0028] A belt module BM as an example of intermediate transfer means is disposed below the photoconductor drums Py-Pk. The belt module BM includes an intermediate transfer belt B as an example of image holding means, a drive roll Rd as an example of a drive means for the intermediate transfer means, a tension roll Rt as an example of a tension applying means, a walking roll Rw as an example of a meandering prevention means, a plurality of idler rolls Rf as an example of a driven means, a backup roll T2a as an example of an opposing means, and the primary transfer rolls T1y, T1m, T1c, and T1k. The intermediate transfer belt B is supported so as to be rotatable in the direction of the arrow Ya.

[0029] A secondary transfer unit Ut is disposed below the backup roll T2a. The secondary transfer unit Ut has a secondary transfer roll T2b as an example of a secondary transfer means. A secondary transfer area Q4 is formed by an area where the secondary transfer roll T2b contacts the intermediate transfer belt B. A backup roll T2a as an example of a counter means faces the secondary transfer roll T2b with the intermediate transfer belt B sandwiched therebetween. A contact roll T2c as an example of a power supply means contacts the backup roll T2a. A secondary transfer voltage having the same polarity as the charging polarity of the toner is applied to the contact roll T2c. The backup roll T2a, the secondary transfer roll T2b, and the contact roll T2c constitute a secondary transfer unit T2, which is an example of a transfer means.

[0030] A medium transport path SH2 is disposed below the belt module BM. The recording paper S fed from the medium supply path SH1 of the feeder unit U2 is transported by a transport roll Ra, which is an example of a medium transport means, to a registration roll Rr, which is an example of a transport timing adjustment means. The registration roll Rr transports the recording paper S downstream in accordance with the timing at which the toner image formed on the intermediate transfer belt B is transported to the secondary transfer area Q4. The recording paper S sent out by the registration roll Rr is guided by a registration side paper guide SGr and a pre-transfer paper guide SG1, and transported to the secondary transfer area Q4. The toner image on the intermediate transfer belt B is transferred to the recording paper S by the secondary transfer device T2 as it passes through the secondary transfer area Q4. In the case of a color toner image, the toner images that are primarily transferred onto the surface of the intermediate transfer belt B in a superimposed manner are secondarily transferred to the recording paper S all at once. The primary transfer rolls T1y to T1k, the secondary transfer unit T2, and the intermediate transfer belt B constitute a transfer device (transfer means) T1y to T1k+T2+B of the first embodiment.

[0031] After the secondary transfer, the intermediate transfer belt B is cleaned by a belt cleaner CLB, which is an example of a cleaning means for the intermediate transfer means and is disposed downstream of the secondary transfer area Q4. The belt cleaner CLB removes residual matter such as developer and paper powder that has not been transferred from the intermediate transfer belt B in the secondary transfer area Q4.

[0032] The recording paper S onto which the toner image has been transferred is guided by a post-transfer paper guide SG2 and sent to a belt conveying device BH, which is an example of a medium conveying means. The belt conveying device BH conveys the recording paper S to a fixing device F. The fixing device F has a heating roll Fh as an example of a heating means and a pressure roll Fp as an example of a pressure means. The recording paper S is transported to a fixing area Q5 where the heating roll Fh and the pressure roll Fp come into contact with each other. When the toner image on the recording paper S passes through the fixing area Q5, the toner image is heated and pressed by the fixing device F and fixed. The visible image forming devices UY+Gy-UK+Gk, the transfer devices T1y-T1k+T2+B, and the fixing device F constitute an image recording unit U3a as an example of an image forming means in the first embodiment.

[0033] A switching gate GT1, which is an example of a switching means, is provided downstream of the fixing device F. The switching gate GT1 selectively switches the recording paper S that has passed through the fixing area Q5 to either the discharge path SH3 or the reversal path SH4 on the media processing device U4 side. The recording paper S transported to the discharge path SH3 is transported to the paper transport path SH5 of the media processing device U4. A curl correction member U4a, which is an example of a warp correction means, is disposed on the paper transport path SH5. The curl correction member U4a corrects the warp, or so-called curl, of the recording paper S that has been brought in. The recording paper S, whose curl has been corrected, is discharged by discharge rolls Rh, which are an example of a medium discharge member, to a discharge tray TH1, which is an example of a medium discharge section, with the image fixing surface of the paper facing upward.

[0034] The recording paper S conveyed to the reverse path SH4 side of the image forming unit U3 by the switching gate GT1 passes through a second gate GT2, which is an example of a switching member, and is conveyed to the reverse path SH4 of the image forming unit U3. At this time, when the recording paper S is discharged with the image fixing surface facing downward, the conveying direction of the recording paper S is reversed after the trailing end of the recording paper S in the conveying direction passes through the second gate GT2. Here, the second gate GT2 in the first embodiment is made of a thin-film elastic member. Therefore, the second gate GT2 passes the recording paper S conveyed to the reversing path SH4 once as it is, and when the recording paper S that has passed through is reversed, that is, switched back, it is guided to the conveying paths SH3 and SH5. Then, the switched back recording paper S passes through the curl correction member U4a and is discharged to the discharge tray TH1 with the image fixing surface facing downward.

[0035] A circulation path SH6 is connected to the inversion path SH4 of the imaging unit U3, and a third gate GT3 as an example of a switching means is disposed at the connection point between them. The downstream end of the inversion path SH4 is connected to an inversion path SH7 of the media processing device U4. The recording paper S transported to the reverse path SH4 through the switching gate GT1 is transported to the reverse path SH7 side of the media processing device U4 by the third gate GT3. The third gate GT3 in the first embodiment is made of a thin elastic material, similar to the second gate GT2. Therefore, the third gate GT3 allows the recording paper S transported along the reverse path SH4 to pass through once, and when the recording paper S that has passed through is switched back, it is guided to the circulation path SH6 side.

[0036] The recording paper S transported to the circulation path SH6 is sent again to the secondary transfer area Q4 via the medium transport path SH2, where the second side is printed. The elements denoted by the reference characters SH1 to SH7 constitute the sheet transport path SH. The elements denoted by the reference characters SH, Ra, Rr, Rh, SGr, SG1, SG2, BH, and GT1 to GT3 constitute the sheet transport device SU of the first embodiment.

[0037] (Description of Fixing Device) FIG. 3 is an enlarged view of the fixing device of the first embodiment. 3, in the fixing device F of Example 1, a conditioning roll 1 as an example of a contact means is disposed opposite the heating roll Fh. The conditioning roll 1 is disposed downstream of the fixing area Q5 with respect to the rotation direction of the heating roll Fh. Therefore, the conditioning roll 1 is disposed in a state of not contacting the recording paper S or the pressure roll Fp. The conditioning roll 1 of Example 1 is configured to be movable between a contact position where it contacts the heating roll Fh (see the solid line in FIG. 3) and a separated position where it is separated from the heating roll Fh (see the dashed line in FIG. 3). Note that the configuration for bringing the conditioning roll 1 into contact with and separating it from the heating roll Fh is conventionally known (see, for example, Patent Document 1, etc.), and various configurations can be adopted, so detailed explanation will be omitted.

[0038] When the heating roll Fh rotates while in contact with the heating roll Fh, the conditioning roll 1 of Example 1 rotates following the heating roll Fh, reducing unevenness in the rough surface of the heating roll Fh. Furthermore, the conditioning roll 1 of Example 1 also has the function of contacting the entire width direction of the heating roll Fh and transferring a large amount of heat from the high temperature region, thereby reducing the temperature difference between the low temperature region in contact with the recording paper S on the heating roll Fh and the high temperature region not in contact with the recording paper S.

[0039] (Description of the control unit of the first embodiment) FIG. 4 is an explanatory diagram of the control unit according to the first embodiment. In FIG. 4, the control unit (controller) C, which is an example of a control means of the copier U, has an input / output interface I / O for inputting and outputting signals from and to the outside. The control unit C also has a ROM (read-only memory) in which programs and information for performing necessary processing are stored. The control unit C also has a RAM (random access memory) for temporarily storing necessary data. The control unit C also has a CPU (central processing unit) for performing processing according to the programs stored in the ROM or the like. Therefore, the control unit C in the first embodiment is composed of a small information processing device, a so-called microcomputer. Therefore, the control unit C can realize various functions by executing programs stored in the ROM or the like. The control unit C in the first embodiment receives a signal from the signal output element and outputs a signal to the controlled element to control it.

[0040] (Description of signal output elements) The control unit C receives signals from signal output elements such as a temperature sensor SN1 and a paper sensor SN2. The temperature sensor SN1 is disposed opposite the conditioning roll 1 and detects the surface temperature T1 of the conditioning roll 1. The paper sensor SN2 is disposed downstream of the fixing area Q5 and detects the recording paper S.

[0041] (Description of controlled element) The control unit C outputs signals to controlled elements such as the conditioning roll 1, the heating roll Fh, the heater Fha, and the power supply circuit E.

[0042] (Function of control unit C) The control unit C of the first embodiment has the following functional means (functional modules, program modules) C1 to C5. The cleaning start time determination means C1 determines whether or not it is time to clean the conditioning roll 1. In the cleaning start time determination means C1 of the first embodiment, the end of a job, which is a series of printing operations, is preset as an example of the time to clean the conditioning roll 1. Note that the time to clean is not limited to the end of a job, and can be any time according to the user's settings, specifications, etc., such as when the cumulative number of printed sheets reaches a predetermined number, when the power is turned on, once a week, etc.

[0043] The heating roll rotation control means C2, which is an example of a heating means rotation control means, controls the rotation of the heating roll Fh. The heating roll rotation control means C2 of the first embodiment rotates the heating roll Fh during a job and also rotates the heating roll Fh during the cleaning operation of the conditioning roll 1. The heater control means C3 as an example of a heat source control means controls the heater Fha as an example of a heat source built into the heating roll Fh. The heater control means C3 of the first embodiment controls the on / off of the heater Fha during a job and during the cleaning operation of the conditioning roll 1 so that the temperature of the fixing area Q5 becomes a predetermined fixing temperature. In the first embodiment, when the cleaning operation of the conditioning roll 1 is started, the conditioning roll 1 is controlled to a high first control temperature in order to quickly heat up the conditioning roll 1, and when the heating of the conditioning roll 1 is completed, the second control temperature is controlled to a temperature lower than the first control temperature. It is desirable that the second control temperature is a temperature at which the developer transferred from the conditioning roll 1 to the heating roll Fh is transferred from the heating roll Fh to the recording paper S and fixed. The control temperature is not limited to two stages, and it is also possible to have one control temperature or three or more control temperatures.

[0044] The conditioning roll movement control means C4 moves the conditioning roll 1 between the contact position and the separated position. The conditioning roll movement control means C4 of the first embodiment moves the conditioning roll 1 to the contact position for a predetermined period during a job when it is necessary to smooth out a rough surface condition or uneven temperature of the heating roll Fh, for example, when a predetermined number of recording sheets S have passed continuously or when small-sized recording sheets S have been used continuously, and moves the conditioning roll 1 to the separated position for the rest of the time. Note that the present invention is not limited to this, and it is also possible to configure the conditioning roll 1 to continue to be held at the contact position during a job. Then, when the cleaning operation of the conditioning roll 1 is started, the conditioning roll 1 is moved to the contact position (if it has already moved to the contact position, it is maintained in the contact position). Next, when the temperature of the conditioning roll 1 reaches a predetermined set temperature Ta, the conditioning roll 1 is moved to the separation position. Next, when the surface temperature of the conditioning roll 1 becomes higher than the surface temperature of the heating roll Fh, the conditioning roll 1 is moved to the contact position. Then, when the cleaning operation is completed, the conditioning roll 1 is moved to the separation position.

[0045] The paper feed control means C5 feeds the recording paper S at a predetermined interval during a job, and when the cleaning operation of the conditioning roll 1 is started, when the surface temperature T1 of the conditioning roll 1 reaches the set temperature Ta, the control means C5 feeds the cooling recording paper S, and when the surface temperature of the conditioning roll 1 becomes higher than the surface temperature of the heating roll Fh, the control means C5 feeds the cleaning recording paper S. In the first embodiment, the cooling recording paper S and the cleaning recording paper S are not dedicated recording paper, but recording paper S stored in the paper feed trays TR1 to TR4 is used, but it is also possible to use a configuration in which dedicated recording paper is used. For example, it is also possible to use thick paper with a large heat capacity as the cooling recording paper, or to use special paper processed so that the developer easily adheres to the surface as the cleaning recording paper. The dedicated recording paper can be set in the paper feed trays TR1 to TR4, or can be fed using the manual feed tray in an image forming apparatus having a manual feed tray.

[0046] (Explanation of the flow chart of the first embodiment) Next, the flow of control in the copying machine U of the first embodiment will be described with reference to a flow chart. FIG. 5 is an explanatory diagram of a flowchart of the cleaning process in the first embodiment. 5 is performed in accordance with a program stored in the control unit C. This processing is performed in parallel with various other processing of the copier U. The flowchart shown in FIG. 5 begins when the copier U is turned on.

[0047] 5, it is determined whether or not the cleaning operation of the conditioning roll 1 has started. If yes (Y), proceed to ST2, and if no (N), repeat ST1. In ST2, the following processes (1) and (2) are executed, and the process proceeds to ST3. (1) The heater of the heating roll Fh is turned on and controlled at the first control temperature. (2) The conditioning roll 1 is moved to the contact position. In ST3, it is determined whether or not the surface temperature T1 of the conditioning roll 1 has reached the set temperature Ta. If yes (Y), proceed to ST4, and if no (N), repeat ST3. In ST4, the following processes (1)-(3) are executed, and the process proceeds to ST5. (1) The conditioning roll 1 is moved to the separated position. (2) Feed the recording paper S for cooling. (3) The control temperature of the heating roll Fh is set to the second control temperature.

[0048] In ST5, it is determined whether or not the trailing edge of the cooled recording paper S has passed through the fixing area Q5. If yes (Y), proceed to ST6, and if no (N), repeat ST5. In ST6, the following processes (1) and (2) are executed, and the process proceeds to ST7. (1) The conditioning roll 1 is moved to the contact position. (2) Feed the recording paper S for cleaning. In ST7, it is determined whether or not the rear end of the recording paper S for cleaning has passed through the fixing area Q5. If yes (Y), proceed to ST8, and if no (N), repeat ST7. In ST8, the heater of the heating roll Fh is put into a standby state (the fixing temperature is maintained at a preset standby temperature), and the conditioning roll 1 is moved to the separated position, completing the cleaning operation of the conditioning roll 1. Then, the process returns to ST1.

[0049] (Function of Example 1) FIG. 6 is an explanatory diagram of temperature changes of the heating roll and the conditioning roll during the cleaning operation in the first embodiment. In the copier U of the first embodiment having the above configuration, when the cleaning operation of the conditioning roll 1 is started, the conditioning roll 1 comes into contact with the heating roll Fh. Therefore, heat is transferred from the heating roll Fh to the conditioning roll 1, and the conditioning roll 1 rises in temperature as shown in FIG. 6. When the conditioning roll 1 is heated to the set temperature Ta, the conditioning roll 1 separates from the heating roll Fh. Therefore, the conditioning roll 1 is in a state of being naturally cooled. Meanwhile, the recording paper S for cooling comes into contact with the heating roll Fh from which the conditioning roll 1 has been separated. Therefore, the heating roll Fh absorbs heat into the recording paper S. Therefore, the surface temperature of the heating roll Fh drops rapidly compared to the surface temperature of the naturally cooled conditioning roll 1. Therefore, the surface temperature of the conditioning roll 1 is in a state of being higher than the surface temperature of the heating roll Fh. In this state, the conditioning roll 1 is brought into contact with the heating roll Fh.

[0050] Developer, paper powder, and the like adhere to the surface of the heating roll Fh from the recording paper S that passes through the fixing area Q5 during a job. Developer and other contaminants also adhere to and accumulate on the conditioning roll 1. The higher the temperature of the developer, the more molten (loose) it becomes, and the more likely it is to solidify at a constant temperature. Therefore, the developer tends to move from the higher temperature component of the heating roll Fh or the conditioning roll 1 to the lower temperature component, and to adhere to it. In a configuration in which no member for cleaning the refresh roll is provided, as in the configuration described in Patent Document 1, developer accumulates on the refresh roll. When the developer accumulates and forms a lump of developer, the lump of developer falls off the refresh roll, adheres to the heating roll, and moves to the recording paper during printing, which may cause image quality defects such as black spots. However, providing a dedicated cleaning member for cleaning the refresh roll increases the number of parts, raising manufacturing costs and the problem of an increase in the size of the fixing device.

[0051] In contrast to these, in the first embodiment, in the cleaning operation of the conditioning roll 1, a state is created in which the surface temperature of the conditioning roll 1 is higher than the surface temperature of the heating roll Fh. Therefore, the developer is easily moved from the high-temperature conditioning roll 1 to the low-temperature heating roll Fh. The developer adhering to the heating roll Fh is then collected by adhering to the recording paper S for cleaning and discharged outside the fixing device F. Thus, the adhering matter adhering to the conditioning roll 1 is cleaned. Therefore, in the first embodiment, the conditioning roll 1 can be cleaned without adding a dedicated configuration for cleaning the conditioning roll 1. That is, it is possible to clean the conditioning roll 1 and suppress the occurrence of image defects while suppressing an increase in the number of parts.

[0052] In particular, in Example 1, the deposits from the conditioning roll 1 are finally transferred to the recording paper S and discharged outside the device. When the deposits are collected inside the device, a maintenance operation is required to periodically discard the collected deposits outside the device, but in Example 1, no periodic maintenance operation is required. In addition, in the first embodiment, the heating roll Fh is cooled by contacting the recording paper S with the heating roll Fh. Therefore, there is no need to add a dedicated cooling device, such as a cooling fan, and an increase in the number of parts is suppressed. In particular, by using the recording paper S, there is no need for a special cooling configuration, and the heating roll Fh can be easily cooled.

[0053] Furthermore, in Example 1, the conditioning roll 1 is heated by contacting it with the heating roll Fh. Therefore, there is no need to add a dedicated component for heating the conditioning roll 1, such as a heater dedicated to the conditioning roll 1, and an increase in the number of parts is suppressed. In addition, in Example 1, after the conditioning roll 1 is heated, a temperature difference with the heating roll Fh is generated simply by separating the conditioning roll 1 from the heating roll Fh. Therefore, it is not necessary to add any special configuration to the conditioning roll 1, and it is possible to create a temperature difference between the conditioning roll 1 and the heating roll Fh with a simple configuration.

[0054] Example 2 FIG. 7 is an explanatory diagram of a fixing device according to the second embodiment, and corresponds to FIG. 3 of the first embodiment. Next, a second embodiment of the present invention will be described. In the description of the second embodiment, components corresponding to those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted. This embodiment 2 differs from the above-mentioned embodiment 1 in the following points, but is otherwise configured similarly to the above-mentioned embodiment 1. In the fixing device F of the second embodiment, a pressure roll Fp as an example of a pressure means is configured to be able to contact and separate from a heating roll Fh. A cleaning web 11 as an example of a cleaning means is disposed on the pressure roll Fp. The cleaning web 11 comes into contact with the surface of the pressure roll Fp to clean off any deposits on the surface of the pressure roll Fp. The contact and separation mechanism of the pressure roll Fp is conventionally known (see, for example, Patent Document 1, etc.), and various conventionally known configurations can be adopted, so detailed description will be omitted. Also, the cleaning web 11 itself is commercially available, so detailed description will be omitted.

[0055] (Explanation of the control unit of the second embodiment) FIG. 8 is an explanatory diagram of a control unit according to the second embodiment, and corresponds to FIG. 4 of the first embodiment. In FIG. 8, a control unit C of the second embodiment differs from the first embodiment in the following points in terms of the controlled elements and functional means. (Description of controlled element) The control unit C of the second embodiment outputs signals to the contact and separation mechanism of the pressure roll Fp as an example of a controlled element, in addition to the respective controlled elements of the first embodiment.

[0056] (Function of control unit C) The control unit C of the second embodiment has a pressure roll movement control means C6 in addition to the means C1 to C5 of the first embodiment. The pressure roll movement control means C6 moves the pressure roll Fp between a close position where the pressure roll Fp approaches the heating roll Fh and a separated position where the pressure roll Fp is separated from the heating roll Fh. The pressure roll movement control means C6 of the first embodiment maintains the pressure roll Fp in contact with the heating roll Fh during a job. Then, when the job is completed, the pressure roll Fp moves to the separated position. After the job is completed, the heating roll Fh is in a standby state. In the standby state, the heater is controlled on / off to maintain the standby temperature, the pressure roll Fp and the conditioning roll 1 are separated, and the motor of the fixing device F is stopped. Then, when the cleaning operation of the conditioning roll 1 is started, the pressure roll Fp is moved to the separated position until the conditioning roll 1 has completed heating up to the set temperature Ta. Then, when the conditioning roll 1 reaches the set temperature Ta, the pressure roll Fp is moved to the approaching position.

[0057] (Explanation of the flow chart of the second embodiment) FIG. 9 is an explanatory diagram of a flowchart of the cleaning process according to the second embodiment, and corresponds to FIG. 5 of the first embodiment. In FIG. 9, in the cleaning process of the second embodiment, the following ST2' and ST4' are executed instead of ST2 and ST4 in the cleaning process of the first embodiment. In ST2', the following steps (1)-(3) are executed, and the process proceeds to ST3. (1) The heater of the heating roll Fh is turned on and controlled at the first control temperature. (2) The conditioning roll 1 is moved to the contact position. (3) The pressure roll Fp is moved to the separated position. In ST4', the following steps (1)-(4) are executed, and the process proceeds to ST5. (1) The conditioning roll 1 is moved to the separated position. (2) Feed the recording paper S for cooling. (3) The control temperature of the heating roll Fh is set to the second control temperature. (4) The pressure roll Fp is moved to the approach position.

[0058] (Function of Example 2) FIG. 10 is an explanatory diagram of temperature changes of the heating roll, the conditioning roll, and the pressure roll during the cleaning operation in the second embodiment, and corresponds to FIG. 6 in the first embodiment. In the copier U of the second embodiment having the above configuration, when the cleaning operation of the conditioning roll 1 is started, the pressure roll Fp separates from the heating roll Fh. Therefore, as shown by the dashed line in FIG. 10, the pressure roll Fp is naturally cooled, and a temperature difference occurs between the pressure roll Fp and the heating roll Fh. Then, when the pressure roll Fp contacts the heating roll Fh, the recording paper S for cooling passes through, and the heat of the pressure roll Fp is also absorbed by the recording paper S. Therefore, the surface temperature of the pressure roll Fp also drops rapidly. Therefore, the surface temperature is in the condition of the conditioning roll 1>the heating roll Fh>the pressure roll Fp. Therefore, the developer and the like attached to the surface of the conditioning roll 1 moves in the order of the heating roll Fh and the pressure roll Fp. Then, the deposits attached to the surface of the pressure roll Fp are removed and cleaned by the cleaning web 11.

[0059] Therefore, in the second embodiment, the cleaning web 11, which is the cleaning means for the pressure roll Fp, can also clean the conditioning roll 1. This eliminates the need to provide a new cleaning means dedicated to the conditioning roll 1, and suppresses an increase in the number of parts. Furthermore, in the second embodiment, there is no need to feed recording paper S for cleaning, and the amount of media used is reduced compared to the first embodiment. 10, when cleaning of the conditioning roll 1 is performed during a job or immediately after the job is completed, the pressure roll Fp is in a high temperature state at the start of cleaning. Therefore, it is possible to deal with this by separating the pressure roll Fp from the heating roll Fh and delaying the timing of recontact of the pressure roll Fp and the timing of feeding the recording paper S for cooling until the temperature of the pressure roll Fp has sufficiently decreased.

[0060] (Modification of the second embodiment) FIG. 11 is an explanatory diagram of temperature changes of the heating roll, the conditioning roll, and the pressure roll during the cleaning operation in a modified example of the second embodiment, and corresponds to FIG. 6 in the first embodiment. 11, it is also possible to have a configuration in which the pressure roll Fp is separated from the heating roll Fh and a sufficient time has elapsed, or the pressure roll Fp is air-cooled with a fan or the like to sufficiently reduce its surface temperature before it is brought into contact with the heating roll Fh. In this case, even if the recording paper S for cooling is not stopped, the surface temperature of the heating roll Fh can be reduced by contact with the pressure roll Fp whose temperature has been sufficiently reduced. In this case, it is not necessary to feed the recording paper S for cooling, and the amount of media used is reduced.

[0061] (Example of change) Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Modifications (H01) to (H08) of the present invention are illustrated below. (H01) In the above embodiment, a copier U is shown as an example of an image forming apparatus, but the present invention is not limited to this and can be applied to a facsimile or a multifunction machine having multiple functions such as a facsimile, printer, copier, etc. Also, the present invention is not limited to a multicolor image forming apparatus, but can be configured as a single-color, so-called monochrome image forming apparatus. (H02) In the above embodiment, the specific numbers exemplified can be changed as appropriate according to changes in design and specifications. For example, the number and intervals of the crests are not limited to the exemplified forms and can be changed according to the purpose.

[0062] (H03) In the above embodiment, the surface temperature T1 of the conditioning roll 1 is detected, but the present invention is not limited to this. For example, if the time required for the conditioning roll 1 to reach the set temperature Ta is known in advance through an experiment or the like, it is also possible to determine the time to separate the conditioning roll 1 based on the elapsed time since the conditioning roll 1 contacted the heating roll Fh. (H04) In the above embodiment, the paper sensor SN2 detects the passage of the recording paper S for cooling or the passage of the recording paper S for cleaning, but this is not limited to this. If the time from the start of paper feeding to passing through the fixing area Q5 is known in advance, it is possible to perform each process based on the time until passing. Also, although the example shows a case where the rear end of the recording paper S passes through the fixing area Q5, this is not limited to this. For example, even if the recording paper S is passing through the fixing area Q5, it is also possible to move the conditioning roll 1 if the target temperature difference is satisfied.

[0063] (H05) In the above embodiment, the heating roll Fh is cooled by contacting the recording paper S or the pressure roll Fp, but this is not limiting. It is also possible to use cooling means such as a cooling fan or cooling means that absorbs heat by contacting a heating roll Fh other than the pressure roll Fp. (H06) In the above embodiment, it is preferable to heat and increase the temperature of the conditioning roll 1 by contacting it with the heating roll Fh, but this is not limiting. For example, it is also possible to configure the conditioning roll 1 itself to have a built-in heater and to increase the temperature. When a heater is built in, no members are disposed outside the conditioning roll 1, so that an increase in size of the fixing device F can be avoided. In this case, it is not necessary to bring the conditioning roll 1 into contact with the heating roll Fh to heat it after the cleaning operation has started, and it is possible to heat the conditioning roll 1 by turning on the heater of the conditioning roll 1 while they are separated from each other.

[0064] (H07) In the above embodiment, the heating roll Fh and the pressure roll Fp are exemplified as the heating means and the pressure means, but they are not limited to these. They can be in any shape, such as a roll shape or a belt shape. Also, instead of the pressure roll Fp that does not have a built-in heater, it is possible to use a heating roll Fh that has heaters built in both the top and bottom. (H08) In the above embodiment, the conditioning roll 1 is rotated following the heating roll Fh, but the present invention is not limited to this. The conditioning roll 1 may be non-rotatable or may rotate at a slower speed than the heating roll Fh, and may rub against the surface of the heating roll Fh. [Explanation of symbols]

[0065] 1... contact means, 11...Cleaning means, F: Fixing device, Fh...Heating means, Fp: Pressurizing means, Py, Pm, Pc, Pk...image holding means, S...medium, T1y~T1k+T2+B...transcription means, U...Image forming device.

Claims

1. A heating means for contacting and heating the medium; a contact means that does not contact the medium and that contacts the heating means; a pressure applying means disposed opposite to the heating means and in contact with the medium to apply pressure to the medium; a cleaning means for cleaning deposits on a surface of the pressing means by contacting the pressing means without contacting the medium; Equipped with a surface temperature of the contact means is made higher than a surface temperature of the heating means to move the deposit from the contact means to the heating means; The deposits transferred from the contact means to the heating means are transferred to the surface of the pressing means and then removed by the cleaning means. A fixing device comprising:

2. After the surface temperature of the contact means becomes higher than the surface temperature of the heating means, the pressure means is brought into contact with the heating means.

2. The fixing device according to claim 1,

3. A heating means for contacting and heating the medium; a contact means that does not contact the medium and that contacts the heating means; Equipped with The heating means is cooled to make the surface temperature of the contact means higher than the surface temperature of the heating means, thereby transferring the deposits from the contact means to the heating means. A fixing device comprising:

4. The heating means is cooled by bringing a medium into contact with the heating means.

4. The fixing device according to claim 3.

5. a pressure applying means arranged opposite to the heating means and contacting the medium to apply pressure to the medium; Equipped with The pressure means is brought into contact with the heating means to cool the heating means, thereby making the surface temperature of the contact means higher than the surface temperature of the heating means.

4. The fixing device according to claim 3.

6. A heating means for contacting and heating the medium; a contact means that does not contact the medium and that contacts the heating means; Equipped with The contact means and the heating means are separated to lower the temperature of the heating means, and then the contact means and the heating means are brought into contact with each other, thereby making the surface temperature of the contact means higher than the surface temperature of the heating means, and transferring the deposits from the contact means to the heating means. A fixing device comprising:

7. Before the contact means and the heating means are separated, the contact means is brought into contact with the heated heating means to increase the surface temperature of the contact means.

7. The fixing device according to claim 6,

8. An image holding means; a transfer means for transferring the image on the surface of the image holding means to a medium; a fixing device according to any one of claims 1 to 7, which fixes the image transferred onto the medium; An image forming apparatus comprising:

Images