JP2008015283A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of reducing the number of sheets of transfer material which gets needless, and achieving the shortening of time and further the improvement of usability. <P>SOLUTION: When performing density or chromaticity control by a control means 300, after fixing a color toner patch for density or chromaticity control on the transfer material, rotators 140 and 160 are heated to predetermined temperature and idly rotated, thereby making toner adhering to cleaning means 145 and 165 flow backward to both rotators 140 and 160. Furthermore, the transfer material 11a on which the color toner patch for density or chromaticity control is fixed is fed to a fixing device 14, and heated and pressured while it is held by both rotators 140 and 160, thereby collecting the toner on both rotators 140 and 160 by the transfer material 11a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer, a copying machine, and a facsimile. More particularly, the present invention relates to an image forming apparatus having a fixing rotator that rotates in contact with each other to form a nip region and a pressure rotator, and having cleaning means for cleaning toner adhering to at least one of the rotators in the fixing device. is there.

Conventionally, as related to cleaning of a fixing device in an image forming apparatus, as disclosed in Patent Document 1, a transfer material or the like set in a paper feed cassette is used as cleaning paper, and the cleaning paper is periodically fixed. Some of them automatically pass through the nip portion and collect the toner adhering to the cleaning roller.
JP 2003-57985 A

  However, in the above method, when the fixing device is cleaned, a medium such as an unused transfer material set in a paper feeding cassette is used as cleaning paper, and the fixing device is cleaned. The main focus is only on.

  Therefore, the present inventor has jammed in a calibration sheet used for color correction by a density or chromaticity detection means (color sensor) regularly performed in a conventional color image forming apparatus or the like, or in the image forming apparatus. Focusing on the use of JAM paper as cleaning paper, it has been found that the above-described problems can be solved. The present invention is based on the novel knowledge of the present inventors.

  An object of the present invention is to provide an image forming apparatus capable of reducing the number of unnecessary transfer materials, reducing time, and improving usability.

The above object is achieved by the image forming apparatus according to the present invention. In summary, according to the first aspect of the present invention,
An image forming unit for forming a toner image on a transfer material;
A pair of rotating bodies that sandwich the transfer material on which the toner image is formed and fix the toner image on the transfer material by heating and pressurizing; and a cleaning unit that cleans the toner adhering to at least one of the rotating bodies; A fixing device comprising:
In an image forming apparatus comprising:
The density or chromaticity control color toner patch formed by the image forming unit is fixed on the transfer material by the fixing device,
The density or chromaticity of the patch fixed on the transfer material is detected by the density or chromaticity detection means,
Control means for controlling image forming conditions based on the detected density or chromaticity of the patch;
When performing density or chromaticity control by the control means,
(I) After fixing the density or chromaticity control color toner patch on the transfer material, the rotating body is heated to a predetermined temperature and rotated idly, and the toner adhering to the cleaning means is applied to the rotating bodies. Backflow,
(Ii) Further, the transfer material on which the density or chromaticity control color toner patch is fixed is fed to the fixing device, and is sandwiched and heated and pressurized by the rotary members. Collect the toner on the transfer material,
A cleaning mode for cleaning the cleaning means;
An image forming apparatus is provided.

According to a second aspect of the invention,
An image forming unit for forming a toner image on a transfer material;
A pair of rotating bodies that sandwich the transfer material on which the toner image is formed and fix the toner image on the transfer material by heating and pressurizing; and a cleaning unit that cleans the toner adhering to at least one of the rotating bodies; A fixing device comprising:
Detecting means for detecting the jam of the transfer material;
In an image forming apparatus comprising:
When the detection unit detects a jam of the transfer material in the image forming apparatus, and the transfer material on which the toner image is fixed by the fixing device remains in the image forming apparatus,
(I) heating the rotating body to a predetermined temperature and causing it to idle, causing the toner adhering to the cleaning means to flow back to both rotating bodies;
(Ii) Further, the transfer material remaining in the image forming apparatus and having the toner image fixed thereon is fed to the fixing device, and the transfer material is sandwiched between the rotating members and heated and pressurized, Collecting the toner on both of the rotating bodies with the transfer material;
A cleaning mode for cleaning the cleaning means;
An image forming apparatus is provided.

  According to the present invention, it is unnecessary to use a calibration sheet used during color correction by a color sensor performed regularly or jammed (JAM) paper jammed in the image forming apparatus as cleaning paper. The number of transfer materials can be reduced, and further, the time can be reduced by not having to perform the cleaning mode again, and the time and effort for the user to execute the cleaning mode can be reduced, thereby improving the usability.

  The image forming apparatus according to the present invention will be described below in more detail with reference to the drawings.

Example 1
FIG. 1 shows a schematic configuration of an embodiment of an image forming apparatus according to the present invention. In this embodiment, the image forming apparatus is a color laser printer which is an example of a color image forming apparatus. First, the overall configuration of the image forming apparatus will be described.

(Overall configuration of image forming apparatus)
According to the present embodiment, four image forming portions in an oblique direction, that is, yellow (Y), magenta (M), cyan (C), and black (Bk) image forming portions P (Pa, Pb, Pc, Pd) are juxtaposed. Each image forming unit P (Pa, Pb, Pc, Pd) includes a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 1 (1a, 1b, 1c, 1d).

  Around each photosensitive drum 1, there is a primary charger (charging roller in this embodiment) 2 (2a, 2b, 2c, 2d) as primary charging means for uniformly charging the surface of the photosensitive drum 1. Has been placed. In addition, the image forming apparatus irradiates the surface of the photosensitive drum 1 uniformly charged by the primary charger 2 with a laser beam based on image information to form an electrostatic latent image as a laser beam as an exposure unit. A scanner 3 (3a, 3b) is arranged.

  A developing device 40 (40a, 40b, 40c, 40d) as a developing unit is disposed around each photosensitive drum 1, and yellow is formed on the surface of the photosensitive drum 1 on which the electrostatic latent image is formed. (Y), magenta (M), cyan (C), and black (Bk) toners are attached to be visualized as a toner image.

  The developing device 40 is unitized into a process cartridge 7 (7a, 7b, 7c, 7d) and a toner cartridge 5 (5a, 5b, 5c, 5d).

  Opposite to the photosensitive drum 1 (1a, 1b, 1c, 1d), an intermediate transfer member is an intermediate transfer member on which the toner image formed on the surface of the photosensitive drum 1 (1a, 1b, 1c, 1d) is primarily transferred. A transfer belt 10 is disposed. The intermediate transfer belt 10 is stretched by a driving roller 10a, a driven roller 10b, and an idler roller 10c, and a secondary transfer roller 16 as a secondary transfer unit is disposed at a position facing the driven roller 10b with the intermediate transfer belt 10 interposed therebetween. Is arranged. The intermediate transfer unit 15 is configured by the intermediate transfer belt 10, the secondary transfer roller 16, and the like.

  The toner image formed on each photosensitive drum 1 is primarily transferred to the intermediate transfer belt 10 by the action of a primary transfer roller 12 (12a, 12b, 12c, 12d) as a primary transfer unit.

  The toner remaining on the surface of the photosensitive drum 1 after the transfer is removed by the cleaning means 8 (8a, 8b, 8c, 8d).

  On the other hand, the transfer material 11a fed from the paper feed cassette 11 by the pickup roller 9 is separated and fed one by one by the separating means of the feed roller 51a and the retard roller 52a, and then transferred to the registration roller pair 17 by the transport roller pair 13a. Sent. When paper is fed from the multi-tray 50, the paper is separated and fed one by one by the separating means of the feed roller 51b and the retard roller 52b, and then fed to the registration roller pair 17 by the transport roller pair 13b. The transfer material 11 a is conveyed between the intermediate transfer belt 10 and the secondary transfer roller 16 by the registration roller pair 17 at a predetermined timing, and is primarily transferred to the intermediate transfer belt 10 by the action of the secondary transfer roller 16. The toner image is secondarily transferred.

  The transfer material 11a onto which the toner image has been transferred has a switching lever 55 that is switched by means such as a solenoid (not shown) after the toner image is fixed by a fixing device 14 as fixing means. In this case, the sheet is conveyed by the discharge roller pair 20 and discharged onto a discharge tray 21 provided at the upper part of the apparatus main body. When the switching lever 55 is at the position 55b as shown in FIG. 2, it is conveyed by the conveying roller pair 13c to the switchback roller pair 31 of the duplex conveying path 30 and conveyed by the switchback roller pair 31. The direction is switched and the sheet passes through the pair of conveying rollers 13d, 13e, and 13f and is conveyed again to the pair of registration rollers 17.

  Here, the fixing device 14 used in a general image forming apparatus will be described with reference to FIG.

  As shown in FIG. 3, in this embodiment, the fixing device 14 includes a fixing roller 140 as a fixing rotator and a pressure roller 160 as a pressure rotator. For example, the fixing roller 140 is provided with a releasable resin layer 142 such as PFA or PTFE on a metal core 141 such as aluminum or iron, and the inside is heated by a heater 143. The temperature of the fixing roller 140 is detected by the surface temperature of the fixing roller 140 by a temperature detecting element 150 serving as a temperature detecting means that contacts the fixing roller 140, and the temperature control circuit intermittently operates the heater 143, whereby the fixing roller 140 The surface temperature of 140 is controlled to a predetermined temperature.

  On the other hand, the pressure roller 160 that is pressed against and rotates against the fixing roller 140 is provided with an elastic layer 162 such as silicon rubber or silicon sponge having heat resistance and low hardness on a metal core 161 such as aluminum or iron. The surface has a coating layer made of a resin having high releasability such as PFA or PTFE. The interior is heated by a heater 163. The temperature of the pressure roller 160 is detected by the surface temperature of the pressure roller 160 by a temperature detection element 151 serving as a temperature detection means in contact with the pressure roller 160, and the temperature control circuit intermittently operates the heater 163. The surface temperature of the pressure roller 160 is also controlled to a predetermined temperature like the fixing roller 140.

  Also, the offset deteriorates due to a decrease in the releasability of the surface of the fixing roller 140 due to the adhesion of calcium carbonate powder contained in the transfer material. The offset toner is transferred from the surface of the fixing roller 140 to the surface of the pressure roller 160 due to the difference in releasability in the transfer material conveyance interval, and is accumulated on the surface of the pressure roller 160. In this process, the toner adhering or accumulating on the pressure roller 160 returns to the back surface of the transfer material or returns to the fixing roller 140, causing the surface of the transfer material to become dirty.

  Furthermore, when an image larger than the paper size is drawn and “marginless” printing is performed without margins, toner is attached to the surfaces of the fixing roller 140 and the pressure roller 160, causing the front and back surfaces of the transfer material to become dirty. Therefore, at least one of the fixing roller 140 and the pressure roller 160, and in this embodiment, a cleaning rotating body as a cleaning unit, that is, the cleaning rollers 145 and 165 are brought into contact with the fixing roller 140 and the pressure roller 160, respectively. By doing so, the toner adhering to the surface of the roller is collected. The cleaning rollers 145 and 165 are usually made of a metal such as aluminum having a small heat capacity because the cleaning property of the toner is improved when it is easily heated.

  The cleaning roller 145 can be brought into contact with and separated from the fixing roller 140, and the cleaning roller 165 can be brought into contact with and separated from the pressure roller 160 by a cam mechanism (not shown).

  In addition, the image forming apparatus has a special transfer material mode, and a special transfer material can be set from an operator operation panel (not shown), a host computer, or the like, and the user selects the mode. Depending on the type and thickness of the transfer material, part of the process conditions such as transfer material conveyance speed and fixing temperature can be changed.

  Further, in recent years, a color image forming apparatus such as the present embodiment has been required to improve the quality of output images. In particular, the gradation of the density and its stability have a great influence on the judgment of the quality of an image given by a human.

  However, in the color image forming apparatus having the above-described configuration, the density of an image to be obtained fluctuates when there are fluctuations in each part of the apparatus due to environmental changes or long-term use.

  In particular, in the case of an electrophotographic color image forming apparatus, even a slight change in density causes the color balance to be lost. Therefore, for yellow (Y), magenta (M), cyan (C), and black (Bk) toners, several kinds of process conditions such as exposure amount and development bias according to absolute humidity, look-up table, etc. It has tone correction means such as (LUT), and based on the absolute humidity measured by the temperature and humidity sensor, the process conditions at that time and the optimum value for tone correction are selected.

  In addition, a density detection toner patch is created on the intermediate transfer belt, the photosensitive drum, etc. with toner of each color so that a constant density-gradation characteristic can be obtained even if each part of the apparatus fluctuates. The density detection means (density detection sensor) 201 (see FIG. 1) for unfixed toner detects the density of the toner patch, and density control is performed by feeding back process conditions such as exposure amount and development bias based on the detection result. Thus, a stable image is obtained.

  However, in the conventional image forming apparatus, the density control using the unfixed toner density detection sensor 201 is performed by forming a patch on an intermediate transfer belt, a photosensitive drum, or the like and detecting it. The change in the color balance of the image due to the transfer and fixing to the transfer material 11a is not controlled.

  The color balance also changes depending on the transfer efficiency in transferring the toner image to the transfer material 11a, and heating and pressurization by fixing.

  This change cannot be handled by density control using the density detection sensor 201 for unfixed toner.

(Density or chromaticity control mode)
Therefore, the present invention has a density or chromaticity control mode. In the density or chromaticity control mode, a density or chromaticity detection means (hereinafter referred to as “color sensor”) 200 that detects the density of a single-color toner image on the transfer material 11a or the chromaticity of a full-color image after transfer and fixing (hereinafter referred to as “color sensor”) 200. 1), a color toner patch for density or chromaticity control (hereinafter abbreviated as "patch") is formed on the transfer material 11a, and then the patch is fixed on the transfer material. The density or chromaticity detected using the image is fed back to process conditions (image formation conditions) such as charge amount, exposure amount, development bias voltage, look-up table (LUT), etc., and finally formed on the transfer material The control unit 300 controls the density or chromaticity of the output image.

  Next, an embodiment of density or chromaticity control of the final output image formed on the transfer material in the present invention will be described.

  In the density or chromaticity control mode by the color sensor 200, a patch is formed in each image forming unit P. On the other hand, the transfer material 11a fed from the paper feed cassette 11 by the pickup roller 9 is separated and fed one by one by the separating means of the feed roller 51a and the retard roller 52a, and then transferred to the registration roller pair 17 by the transport roller pair 13a. Sent. When paper is fed from the multi-tray 50, the paper is separated and fed one by one by the separating means of the feed roller 51b and the retard roller 52b, and then fed to the registration roller pair 17 by the transport roller pair 13b. The transfer material 11a is conveyed between the intermediate transfer belt 10 and the secondary transfer roller 16 at a predetermined timing by the registration roller pair 17, and is a patch that is primarily transferred to the intermediate transfer belt 10 by the action of the secondary transfer roller 16. Is secondarily transferred.

  After the toner image is fixed by the fixing device 14 on the transfer material 11a to which the patch has been transferred, the switching lever 55 is switched to the position 55b (FIG. 2) by means such as a solenoid (not shown), and the conveying roller pair 13c. Thus, the sheet is conveyed to the switchback roller pair 31 of the duplex conveyance path 30 parts. Next, the conveyance direction is switched by the switchback roller pair 31, and the patch is read by the color sensor 200 through the conveyance roller pair 13 d and 13 e.

  After the patch is read by the color sensor 200, the fixed transfer material 11a passes through the conveying roller pair 13f, is conveyed again to the registration roller pair 17, and temporarily stops.

  At this time, the cleaning rollers 145 and 165 are in contact with the fixing roller 140 and the pressure roller 160, respectively. Further, as shown in FIG. 3, the cleaning rollers 145 and 165 detect the surface temperature of each roller. Temperature detecting elements 146 and 166 are arranged.

  Therefore, in the cleaning mode for cleaning the cleaning rollers 145 and 165 in the present embodiment, the temperature of the roller is adjusted by the temperature control when the patch is fixed to the transfer material before, that is, the print temperature control performed during normal image formation. Perform idle rotation.

  At this time, if the melting point of the toner used in the image forming apparatus is 150 ° C., the toner moves from the high temperature to the low temperature until the temperature of the cleaning rollers 145 and 165 exceeds 150 ° C. This is performed until the temperature at which the toner can flow back is obtained.

  This is because when the temperature of the cleaning rollers 145 and 165 exceeds the melting point of the toner, the toner adhering to the cleaning rollers 145 and 165 melts and flows backward to the fixing roller 140 and the pressure roller 160.

  When the temperature of the cleaning rollers 145 and 165 exceeds 150 ° C., which is the melting point of the toner used in the image forming apparatus, the fixed transfer material 11a is again transferred from the resist roller pair 17 to the fixing device 14. To be sent to.

  At this time, since the image forming apparatus has a special transfer material mode, the idling is performed by setting the mode to a higher fixing temperature, thereby further promoting the reverse flow and shortening the idling time. can do. For this reason, when the special transfer material mode of the image forming apparatus is, for example, five types, the fixing temperature control settings are T1 (° C.), T2 (° C.), T3 (° C.), T4 (° C.), T5 Assuming that the temperature relationship is T1 <T2 <T3 <T4 <T5 and the temperature adjustment when fixing the patch is T1 (° C.), the fixing temperature adjustment after the patch reading is T1 ( When the temperature adjustment when fixing the patch is T5 (° C.), for example, the protection circuit for fixing temperature adjustment does not work. By setting to (° C.) + 5 (° C.), the backflow of the toner adhering to the cleaning roller is promoted and the idling time is shortened.

  In addition, it goes without saying that the value of +5 (° C.) within the temperature at which the protective circuit does not operate is not limited to this value.

  Further, in this embodiment, when the temperature control when the patch is fixed is T5 (° C.), the temperature is set to +5 (° C.) within the temperature where the protection circuit does not work. However, by setting the temperature different from T5 (° C.) In order to promote the back flow of the toner, T4, T3, T2, and T1 may be set.

  The toner that has flowed back from the cleaning rollers 145 and 165 to the fixing roller 140 and the pressure roller 160 when the fixed transfer material 11a passes through the fixing nip N again is collected by the transfer material 11a. The transfer material 11a from which the toner has been collected is conveyed by the discharge roller pair 20 and discharged onto a discharge tray 21 provided at the upper part of the apparatus main body when the switching lever 55 is at the position 55a shown in FIG. The

  FIG. 4 is a flowchart showing a specific example of the processing procedure in the cleaning mode according to the present embodiment in which the transfer material is used as the cleaning paper after the toner patch is formed and detected.

  In step S401, it is determined whether a signal sent from a host (not shown), an image processing control unit, or the like is a density or chromaticity control command. In step S402, whether the transfer material after reading the patch is used as cleaning paper. Judge whether or not. If it is determined in step S402 that the transfer material after reading the patch is used as cleaning paper, feeding of the transfer material is started in step S403a, the patch is transferred to the transfer material in step S404a, and the patch is transferred in step S405a. To settle. In step S406, the fixing temperature adjustment is started. In step S407a, the transfer material is reversed. In step S408a, the transfer material is conveyed in the double-sided conveyance path. In step S409a, a patch on the transfer material is detected. Make adjustments. Next, in step S410, it is confirmed whether or not the temperature adjustment temperature for which the fixing temperature adjustment has been changed in step S406 has reached a predetermined temperature. In step S411, the transfer material after the patch reading is passed through the fixing nip N, and the dirt on the cleaning roller in the fixing device is discharged onto the transfer material. In step S412, the transfer material is discharged out of the device.

  On the other hand, if it is determined in step S402 that the transfer material after reading the patch is not used as cleaning paper, feeding of the transfer material is started in step S403b, the patch is transferred to the transfer material in step S404b, and the patch is transferred in step S405b. Is fixed to the transfer material. In step S407b, the transfer material is reversed. In step S408b, the transfer material is conveyed in the double-sided conveyance path. In step S409a, a patch on the transfer material is detected, and the LUT is adjusted. In step S412, the transfer material is discharged out of the apparatus.

  Note that the setting of whether or not to use the transfer material after reading the patch as cleaning paper for removing dirt on the cleaning roller can be switched and can be set by the user.

  Further, when the transfer material 11a to which the patch is transferred is a small size paper such as a postcard, a post card, an envelope, etc., the dirt discharged to the fixing roller and the pressure roller cannot be recovered with these small size paper. The “cleaning roller cleaning mode” is not performed because it causes image defects during normal printing.

  As described above, by using the transfer material after reading the patch as cleaning paper, the toner on the cleaning roller can be collected without using unprinted paper on the paper feed cassette 11 or the multi-tray 50. . Therefore, it is possible to avoid wasting media such as unused brand new transfer materials. Furthermore, the time is reduced by not having to perform the cleaning mode again, and the time and effort required for the user to execute the cleaning mode are also reduced.

Example 2
Next, a second embodiment of the present invention will be described.

  FIG. 5 shows a schematic configuration of another embodiment of the image forming apparatus according to the present invention.

  The image forming apparatus shown in FIG. 5 has the same configuration as that of the image forming apparatus according to the first embodiment described with reference to FIG. Accordingly, members having the same configuration and function in the image forming apparatus according to the present embodiment are denoted by the same reference numerals as those of the image forming apparatus according to the first embodiment, and the description of the first embodiment is used. Description of is omitted.

  This embodiment is different from the first embodiment in that jammed paper is used as cleaning paper instead of using the transfer material after reading the patch as cleaning paper.

  According to the present embodiment, as shown in FIG. 5, the pre-registration sensor 60 that is a transfer material detection unit is disposed in the vicinity of the registration roller pair 17. The pre-registration sensor 60 is a sensor that determines whether or not the transfer material 11a is conveyed to the registration roller pair 17 from the paper feed cassette 11, the multi-tray 50, or the double-sided conveyance path 30 at a predetermined timing. When it is detected by the pre-registration sensor 60 that the transfer material 11a does not pass at a predetermined timing, it is determined, for example, “pre-registration delay jam”.

  Further, according to the present exemplary embodiment, the pre-fixing sensor 61 and the fixing paper discharge sensor 62 that are transfer material detection units are disposed at the entrance and exit of the fixing device 14, respectively.

  The pre-fixing sensor 61 is arranged in the middle of the conveyance path from the secondary transfer roller 16 to the fixing unit 14, and the transfer material 11a fed by the registration roller pair 17 is conveyed to the fixing device 14 at a predetermined timing. It is a sensor that determines whether or not it has been performed. When it is detected by the pre-fixing sensor 61 that the transfer material 11a does not pass at a predetermined timing, for example, “wrapping around the intermediate transfer belt unit including the intermediate transfer belt 10, the secondary transfer roller 16 and the like” Jam ”.

  Further, the fixing paper discharge sensor 62 is disposed downstream of the fixing nip portion N composed of the fixing roller 140 and the pressure roller 160, and the transfer material 11a fixed by the fixing device 14 is fixed at a predetermined timing. It is a sensor which judges whether it is discharged from. When it is detected by the fixing paper discharge sensor 62 that the transfer material 11a does not pass at a predetermined timing, for example, it is determined as “wrapping jam” to a roller in the fixing device 14.

  Further, jams detected by the pre-registration sensor 60, the pre-fixing sensor 61, and the fixing paper discharge sensor 62 are displayed on the operator operation panel to prompt the user to appropriately perform the jam processing. However, if the number of printed sheets is large, and if a jam occurs in the fixing device in the middle of continuous printing, for example, as shown in FIG. 6, the transfer material 11c other than the transfer material 11b determined to be jammed. , 11d, 11e, and 11f also remain in the image forming apparatus.

  At this time, “fixed winding jam” or the like is displayed on the operator operation panel, and the user is prompted to remove the jammed paper in the fixing device 14, that is, the transfer material 11b. Even after the user removes the transfer material 11b, the transfer material 11c remains on the secondary transfer roller 16 even if the user thinks that the jam processing has been completed. "Next transfer portion jammed paper remaining" is displayed, and the user is prompted to remove the jammed paper on the secondary transfer roller 16 portion, that is, the transfer material 11c.

  After the transfer material 11c is removed by the user, the remaining jammed paper becomes 11d, 11e, and 11f. The residual paper passes through the fixing device 14 once and further upstream from the registration roller pair 17. Will be located. That is, the jammed papers 11d, 11e, and 11f remain at positions that are not directly related to the intermediate transfer belt unit 15 and the fixing device 14 in the image forming apparatus.

  Further, jammed paper 11d, 11e, and 11f remaining at positions not directly related to the intermediate transfer belt unit 15 and the fixing device 14 constituted by the intermediate transfer belt 10 and the secondary transfer roller 16 in the image forming apparatus. Are normally discharged out of the image forming apparatus by an “automatic paper discharge mode” which is a function provided in the image forming apparatus.

  According to the present exemplary embodiment, the cleaning rollers 145 and 165 are smudged on the in-machine residual paper remaining in a position not directly related to the intermediate transfer belt unit 15 and the fixing device 14 in the image forming apparatus. Discharge.

  Here, the transfer material 11d passes through the transport roller pair 13f, is transported again to the registration roller pair 17, and temporarily stops.

  At this time, the cleaning rollers 145 and 165 are in contact with the fixing roller 140 and the pressure roller 160, respectively. Further, as shown in FIG. 3, the cleaning rollers 145 and 165 detect the surface temperature of each roller. Temperature detecting elements 146 and 166 are arranged.

  Therefore, when executing the cleaning mode, as in the first embodiment, assuming that the melting point of the toner used in the image forming apparatus is 150 ° C., the cleaning roller 145 causes the idle rotation of the roller by adjusting the print temperature. , 165 until the temperature exceeds 165C. This is because when the temperature of the cleaning rollers 145 and 165 exceeds the melting point of the toner, the toner adhering to the cleaning rollers 145 and 165 flows back to the fixing roller 140 and the pressure roller 160. When the temperature of the cleaning rollers 145 and 165 exceeds 150 ° C., which is the melting point of the toner used in the image forming apparatus, the transfer material 11 d is conveyed from the registration roller pair 17 to the fixing device 14.

  At this time, since the image forming apparatus has the special transfer material mode, as described in the first embodiment, the reverse flow progresses by performing idling while setting the mode to a higher fixing temperature. Can be further promoted to reduce the idling time.

  Note that the temperatures of the fixing roller 140 and the pressure roller 160 during idling can be set as appropriate as in the first embodiment.

  Then, when the transfer material 11d passes through the fixing nip portion N, the toner that has flowed back from the cleaning rollers 145 and 165 to the fixing roller 140 and the pressure roller 160 is collected by the transfer material 11d. The transfer material 11d from which the toner has been collected is conveyed by the discharge roller pair 20 by the switching lever 55 at the position 55a indicated by a one-dot chain line in FIG. Discharged to the top.

  Note that the residual paper in the machine used as the cleaning paper may use not only the transfer material 11d but also the transfer materials 11e and 11f, so that the cleaning can be completed more completely.

  In addition, the setting as to whether or not the residual paper in the apparatus is used as cleaning paper for removing dirt on the cleaning roller can be switched and can be set by the user.

  In this way, by using the transfer materials 11d, 11e, and 11f remaining at positions not directly related to the intermediate transfer belt unit 15 and the fixing device 14 in the image forming apparatus as cleaning paper, The toner on the cleaning rollers 145 and 165 can be collected without using an unprinted transfer material on the tray 50. Therefore, it is possible to avoid wasting unused brand new transfer material. Furthermore, it is possible to reduce time by not having to perform the cleaning mode again, and to reduce time and effort for the user to execute the cleaning mode.

  In this embodiment, when a jam occurs around the intermediate transfer belt unit 15 such as the intermediate transfer roller 10 and the secondary transfer roller 16 or the fixing device 14, the remaining paper in the image forming apparatus is discharged out of the apparatus. If the “automatic paper discharge mode” is activated immediately, damage such as damage to the intermediate transfer belt unit 15 and the fixing device 14 in the image forming apparatus can be considered. Therefore, if jammed paper that is likely to cause damage to the devices in the image forming apparatus such as the intermediate transfer belt unit 15 and the fixing device 14 remains, the “automatic paper discharge mode” is set unless the user removes the jammed paper. Do not operate.

  Therefore, in this embodiment, when the automatic paper discharge mode is activated, the cleaning mode is activated to discharge the cleaning roller.

  In addition, when the transfer material remaining in the machine is a small size paper such as a postcard, postcard, envelope, etc., it is discharged from the cleaning roller to the fixing roller and the pressure roller. The “cleaning roller cleaning mode” is not performed because the dirty stains cannot be collected and cause image defects during normal printing.

  The image forming apparatus according to the present invention is not limited to the above-described embodiments, and can be variously modified within a range well known to those skilled in the art. For example, the optical system may be one using an LED array other than the one that scans laser light with a polygon mirror, and a number of sensors for detecting jams in the middle of the conveyance path may be arranged in addition to the above three. Further, the present invention is not limited to a color image forming apparatus, but can be similarly applied to a mono-color image forming apparatus to achieve the same effects.

1 is a schematic cross-sectional view of a first embodiment of an image forming apparatus according to the present invention. FIG. 2 is a schematic configuration cross-sectional view of an embodiment of the image forming apparatus according to the present invention similar to FIG. 1, showing a state in which a transfer material conveyance path is switched by a switching lever. 1 is a schematic cross-sectional view of an embodiment of a fixing device according to the present invention. 4 is a flowchart illustrating an example of the operation of the image forming apparatus according to the present invention. It is a schematic structure sectional view of the 2nd example of the image forming device concerning the present invention. FIG. 7 is a schematic cross-sectional view of a second embodiment of the image forming apparatus according to the present invention similar to FIG. 5, illustrating a discharge operation mode of residual paper in the image forming apparatus.

Explanation of symbols

1 (1a, 1b, 1c, 1d) Photosensitive drum (image carrier)
2 (2a, 2b, 2c, 2d) Primary charger (charging means)
3 (3a, 3b) Exposure apparatus (exposure means)
10 Intermediate transfer belt (intermediate transfer member)
11 (11a to 11f) Transfer material 14 Fixing device (fixing means)
15 Intermediate transfer unit 16 Secondary transfer roller (secondary transfer means)
17 Registration roller pair 30 Double-sided conveyance path 31 Switchback roller pair 40 (40a, 40b, 40c, 40d) Developing device (developing means)
55 Switching lever 60 Pre-registration sensor (transfer material detection means)
61 Pre-fixing sensor (transfer material detecting means)
62 Fixing paper discharge sensor (transfer material detecting means)
140 Fixing roller (fixing rotating body)
145, 165 Cleaning roller (cleaning rotator, cleaning means)
146, 166 Temperature detection element (temperature detection means)
150, 151 Temperature detection element (temperature detection means)
160 Pressure roller (Pressure rotating body)
200 Color sensor (Density or chromaticity detection means)
201 Unfixed density detection sensor (unfixed density detection means)
300 Control means

Claims (9)

An image forming unit for forming a toner image on a transfer material;
A pair of rotating bodies that sandwich the transfer material on which the toner image is formed and fix the toner image on the transfer material by heating and pressurizing; and a cleaning unit that cleans the toner adhering to at least one of the rotating bodies; A fixing device comprising:
In an image forming apparatus comprising:
The density or chromaticity control color toner patch formed by the image forming unit is fixed on the transfer material by the fixing device,
The density or chromaticity of the patch fixed on the transfer material is detected by the density or chromaticity detection means,
Control means for controlling image forming conditions based on the detected density or chromaticity of the patch;
When performing density or chromaticity control by the control means,
(I) After fixing the density or chromaticity control color toner patch on the transfer material, the rotating body is heated to a predetermined temperature and rotated idly, and the toner adhering to the cleaning means is applied to the rotating bodies. Backflow,
(Ii) Further, the transfer material on which the density or chromaticity control color toner patch is fixed is fed to the fixing device, and is sandwiched and heated and pressurized by the rotary members. Collect the toner on the transfer material,
A cleaning mode for cleaning the cleaning means;
An image forming apparatus.   2. The image forming apparatus according to claim 1, wherein the rotating body is rotated idly by heating to a fixing temperature at which the density or chromaticity control color toner patch is fixed on the transfer material.   The image forming apparatus according to claim 1, wherein the rotating body is idly rotated by heating to a temperature different from a fixing temperature at which the color toner patch for density or chromaticity control is fixed on the transfer material.   The image forming apparatus according to claim 4, wherein the rotating body is rotated idly by heating to a temperature higher than a fixing temperature at which the color toner patch for density or chromaticity control is fixed on the transfer material. An image forming unit for forming a toner image on a transfer material;
A pair of rotating bodies that sandwich the transfer material on which the toner image is formed and fix the toner image on the transfer material by heating and pressurizing; and a cleaning unit that cleans the toner adhering to at least one of the rotating bodies; A fixing device comprising:
Detecting means for detecting the jam of the transfer material;
In an image forming apparatus comprising:
When the detection unit detects a jam of the transfer material in the image forming apparatus, and the transfer material on which the toner image is fixed by the fixing device remains in the image forming apparatus,
(I) heating the rotating body to a predetermined temperature to idle, causing the toner adhering to the cleaning means to flow back to both rotating bodies;
(Ii) Further, the transfer material remaining in the image forming apparatus and having the toner image fixed thereon is fed to the fixing device, and the transfer material is sandwiched between the rotary members and heated and pressurized, Collecting the toner on both of the rotating bodies with the transfer material;
A cleaning mode for cleaning the cleaning means;
An image forming apparatus.   The image forming apparatus according to claim 5, wherein the rotating body is rotated idly by heating to a fixing temperature at which the toner image is fixed on the transfer material.   6. The image forming apparatus according to claim 5, wherein the rotating body is idly rotated by heating to a temperature different from a fixing temperature for fixing the toner image on the transfer material.   The image forming apparatus according to claim 7, wherein the rotating body is rotated idly by heating to a temperature higher than a fixing temperature for fixing the toner image on the transfer material.   6. The image forming apparatus according to claim 1, wherein whether or not to execute a cleaning mode for cleaning the cleaning unit is determined according to a type of the transfer material.

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