JP2008122512A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To recover toner adhering to rotary bodies by a recovering member, and to recover the recovered toner by cleaning materials of different sizes at the nip area of the rotary bodies, in an image forming apparatus in which toner images are transferred beyond the edges of the transfer materials. <P>SOLUTION: A control means 200 has, as a cleaning mode, a first cleaning mode in which the rotary bodies 21 and 22 are maintained at a heating temperature for a toner image and, according to the number of transfer sheets to which toner images are transferred beyond the edges of the transfer materials, a conveying means 5 conveys at least one transfer materials as cleaning materials. In addition, the control means has a second cleaning mode in which the rotary bodies are maintained at the heating temperature for a toner image and, according to the cumulative number of transfer materials to which toner images are transferred beyond the edges of the transfer materials, the conveying means conveys, as cleaning materials, the transfer materials greater than the cleaning materials in the size of the lengthwise direction orthogonal to the direction of transfer material conveyance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that transfers a toner image formed and supported on an image carrier such as an electrophotographic photosensitive member onto a transfer material.

  In image forming apparatuses such as electrophotographic copying machines and electrophotographic printers, margins (such as silver halide photography) are reduced due to the recent diversification of printer demand and the spread of digital image recording apparatuses such as digital still cameras. There is an increasing demand for printing without borders. Borderless printing has already been put to practical use in an inkjet image forming apparatus in recent years. Thus, an apparatus capable of borderless printing (printing) has been desired even in an electrophotographic image forming apparatus.

  In an electrophotographic image forming apparatus, when borderless printing is performed on a transfer material, the toner image is transferred to the transfer material so as to protrude from the leading edge, rear edge, left edge, and right edge of the transfer material. Accordingly, a part of the toner image is also transferred to the edge surfaces (side surfaces) of the front end portion, rear end portion, left end portion, and right end portion of the transfer material. The transfer material is nipped and conveyed at a nip portion between the outer peripheral surface (surface) of the fixing roller of the fixing device (fixing device) and the outer peripheral surface (surface) of the pressure roller. In the conveying process, the unfixed toner image is heated and fixed to the transfer material by receiving heat and pressure at the nip portion.

  When the transfer material is nipped and conveyed at the nip portion of the fixing device, the toner image transferred onto the edge surface of the transfer material may adhere to the surface of the fixing roller and the pressure roller. The toner may adhere again to the transfer material as the fixing roller and the pressure roller rotate, and may contaminate the transfer material.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a technique in which cleaning paper is periodically fed to the nip portion and toner attached to the surface of the fixing roller and the pressure roller is transferred to the paper.

In Patent Document 2, toner collected on the surface of the pressure roller is collected and collected by the cleaning roller, and when the number of transfer materials onto which the toner images are transferred reaches a predetermined number, the collected toner is transferred from the cleaning roller to the pressure roller. A technique for transferring to the paper is described.
JP 2003-098886 A JP 2003-57985 A

  However, when a cleaning method using cleaning paper is applied to an image forming apparatus capable of performing borderless printing and having a cleaning roller, the following problems occur.

  When borderless printing is continued using a transfer material of a size smaller than the maximum width transfer material that can fix the toner image by the fixing device, the width of the roller in the longitudinal direction where the toner adheres on the cleaning roller is The width of the transfer material is widened. This is because the toner adhering to the outer peripheral surface (surface) of the cleaning roller is crushed by the action of pressure in the cleaning nip formed by the surface of the cleaning roller and the outer peripheral surface (surface) of the pressure roller. This is because of the spread.

  On the other hand, when the transfer material is transported in the fixing device or when the cleaning paper is transported in the fixing device, the relative positional relationship between the fixing device and the transfer material or the cleaning paper is set in the longitudinal direction of the roller. Variations may occur. In such a situation, when a cleaning mode in which the cleaning paper having the same width as the transfer material on which borderless printing is performed is conveyed to the fixing device and the toner collected by the cleaning roller is collected by the cleaning paper at the nip portion is executed, The following problems arise. The toner in the toner adhesion area through which the cleaning paper passes in the toner adhesion area on the surface of the cleaning roller can be collected again, but the toner in the toner adhesion area through which the cleaning paper does not pass cannot be collected again. That is, it is not possible to recover all the toner in the toner adhesion area. Accordingly, the toner in the toner adhesion area through which the cleaning paper does not pass causes the transfer material to become dirty in the subsequent heat fixing process.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to collect toner adhering to a rotating member by a collecting member in an image forming apparatus in which a toner image is transferred onto the transferring material by protruding the edge of the transferring material, and the collected toner is collected in the nip of the rotating member. So that it can be collected with cleaning materials of different sizes.

The configuration according to the present invention includes a transport unit that transports a transfer material, an image carrier that carries a toner image, and a transfer unit that transfers a toner image on the image carrier to a transfer material transported by the transport unit. A rotating body that heats and fixes a toner image to the transfer material while the transfer material is nipped and conveyed by a nip portion; a recovery member that recovers toner attached to the rotary body; and a toner that is recovered by the recovery member And a control unit having a cleaning mode for collecting the toner image by a cleaning material at a nip portion of the rotating body, and the transfer unit protrudes an edge of the transfer material to transfer a toner image onto the transfer material. A device,
In the cleaning mode, at least one or more sheets are transferred by the transport unit according to the number of transfer materials on which the rotating body is held at the heating temperature of the toner image and the edges of the transfer material are protruded by transferring the toner image. A first cleaning mode in which the transfer material is conveyed as a cleaning material, and the rotating body is maintained at the heating temperature of the toner image and the edge of the transfer material is protruded to transfer the toner image to the accumulated number of transfer materials. And a second cleaning mode in which a transfer material having a size in a longitudinal direction orthogonal to the transfer material conveyance direction larger than that of the cleaning material is conveyed as a cleaning material by a conveyance means.

  According to the present invention, in an image forming apparatus in which a toner image is transferred onto a transfer material by protruding the edge of the transfer material, the toner adhering to the rotating body is recovered by the recovery member, and the recovered toner is collected at the nip portion of the rotating body. And can be collected by cleaning materials of different sizes.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

(1) Example of Image Forming Apparatus FIG. 1 is a structural model diagram of an example of an image forming apparatus according to the present invention. This apparatus is an electrophotographic printer that supports borderless printing.

  In the following description, with respect to the image forming apparatus, the fixing device, and its constituent members, the longitudinal direction is a direction orthogonal to the transfer material conveyance direction on the surface of the transfer material. The longitudinal direction is also the axial direction of the photosensitive drum. The short side direction is the transfer member conveyance direction on the surface of the transfer material.

  In the image forming apparatus 100 shown in this embodiment, the maximum size of the transfer material P that can be used is SRA3 (width 320 mm × length 450 mm). The process speed is 190 mm / second. The printing speed (printing speed) for A4 horizontal feed can be 40 sheets / minute. Further, the transfer material P has a function of forming an image in a borderless print mode and a function of forming an image in a bordered print mode. Further, the transfer material P has a function of forming an image in a single-sided printing mode and a function of forming an image in a double-sided printing mode. The print controller (control means) 200 includes a CPU and a memory such as a ROM and a RAM. The memory stores various data and control programs necessary for image formation such as a borderless print mode, a bordered print mode, a single-sided print mode, and a double-sided print mode. The selection of the borderless printing mode or the bordered printing mode and the selection of the single-sided printing mode or the double-sided printing mode are instructed by an external device such as a host computer connected to the image forming apparatus 100. In this embodiment, it is assumed that the borderless printing mode is designated for the image forming apparatus 100.

  The image forming apparatus 100 according to the present exemplary embodiment executes an image forming control sequence corresponding to borderless printing when the print controller (control unit) 200 receives the borderless printing signal. First, a drum-type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) 1 as an image carrier is rotationally driven in a direction indicated by an arrow at a predetermined process speed by a rotational driving system (not shown). During the rotation of the photosensitive drum 1, the outer peripheral surface (surface) of the photosensitive drum 1 is uniformly charged to a predetermined potential and polarity by a charging roller (charging means) 2. Then, an exposure device (exposure means) 3 irradiates the surface of the photosensitive drum 1 with a laser beam L corresponding to image information, and irradiates the surface of the photosensitive drum 1 to remove charges. An electrostatic latent image (electrostatic image) is formed on one surface. The developing device (developing unit) 4 includes a developing container 4a that stores toner and a developing sleeve 4b. Then, toner is supplied from the developing sleeve 4b to the surface of the photosensitive drum 1, and the latent image is developed as a toner image by the toner.

  On the other hand, the transfer material (recording paper, OHP sheet, etc.) P fed one by one from the feeding cassette 5 by the pickup roller 6a is conveyed to a registration roller (hereinafter referred to as registration roller) 6b. The registration roller 6 b conveys the transfer material P to the transfer nip T between the photosensitive drum 1 and the transfer roller (transfer means) 7 in synchronization with the image formation timing. The transfer material P is nipped and conveyed by the photosensitive drum 1 and the transfer roller 7 at the transfer nipping portion T. In the conveying process, the toner image on the surface of the photosensitive drum 1 is transferred onto the surface of the transfer material P by the transfer roller 7.

  Here, transfer of the toner image onto the transfer material P in borderless printing will be described. FIG. 2A is an explanatory diagram showing a transfer area of a toner image onto the transfer material P by borderless printing, and FIG. 2B is an explanatory diagram showing toner transferred onto the edge surface of the transfer material P.

  In borderless printing, as shown in FIG. 2A, a mask area Am for determining a printing area for the transfer material P is set to have a predetermined width for each of the front end portion, rear end portion, left end portion, and right end portion of the transfer material P. The transfer material P is made larger than the transfer material P by the additional area An of (2 mm). Then, a toner image corresponding to the mask area Am including the area of the additional area An is formed on the surface of the photosensitive drum 1, and the toner image is transferred onto the transfer material P surface by the transfer roller 7, thereby transferring the transfer material P. Achieving borderless printing. By performing borderless printing by such a method, when the transfer material P passes through the transfer nip portion T, the transfer material P is skewed due to conveyance failure, or the transfer material P is relative to the longitudinal direction of the transfer roller 7. Even if position variations occur, borderless printing can always be performed on the transfer material P satisfactorily.

  In the borderless printing, a part of the toner in the added region An outside the transfer material P adheres to the outer peripheral surface (surface) of the transfer roller 7 when the toner image is transferred. The toner adhering to the surface of the transfer roller 7 adheres to the back surface of the transfer material P and causes back contamination. The toner adhering to the surface of the transfer roller 7 is removed by a cleaning blade 12a provided in the cleaner 12 (second cleaning means). As a result, the occurrence of back contamination of the transfer material P is prevented.

  The transfer material P separated from the surface of the photosensitive drum 1 and exiting the transfer nip T is introduced into the nip N of the fixing device (fixing means) 8. The fixing device 8 sandwiches and conveys an unfixed toner image on the transfer material P by a fixing roller 21 and a pressure roller 22 as rotating bodies at a nip portion N. The toner image is heated and fixed on the surface of the transfer material P by applying heat and pressure to the toner image in the conveying process.

  By the way, in borderless printing, a part of the toner in the added area An outside the transfer material P when the toner image is transferred is the edge surface (side surface) of the front end portion, rear end portion, left end portion and right end portion of the transfer material P. (FIG. 2B). Therefore, in the process of nipping and conveying the transfer material P at the nip portion N of the fixing device 8, the toner on the edge surface adheres to the outer peripheral surface (surface) of the fixing roller 21 and the outer peripheral surface (surface) of the pressure roller 22 as offset toner. Sometimes. In order to collect the offset toner, a cleaning roller 24 as a recovery member is brought into contact with the surface of the fixing roller 21, and a cleaning roller 25 as a recovery member is brought into contact with the surface of the pressure roller 22. The configuration of the fixing device 8 will be described later.

  The transfer material P exiting the fixing device 8 is conveyed by discharge rollers 6c and 6d and discharged onto a discharge tray 9 provided on the upper portion of the apparatus main body 101.

  Residual toner remaining on the surface of the photosensitive drum 1 after separation of the transfer material P is removed by a cleaning blade 10 a provided in the cleaning device 10. The surface of the photosensitive drum 1 from which the transfer residual toner has been removed is repeatedly used for image formation.

  The above is the image forming operation when the single-sided printing mode is designated together with the borderless printing mode.

  When the double-sided printing mode is designated together with the borderless printing mode, the transfer material P is switched back by the discharge rollers 6c and 6d and conveyed to the reversing path (transfer material reversing means) 11 provided at the lower part of the apparatus main body 101. To do. The transfer material P conveyed to the reverse path 11 is sent to the registration roller 6b by the conveyance rollers 6e, 6f, 6g, and 6h. As a result, the transfer material P is turned upside down.

  The transfer material P with the front and back reversed is conveyed to the transfer nip portion by the registration roller 6b, and the toner image on the surface of the photosensitive drum 1 is transferred to the transfer material P surface on the photosensitive drum 1 side by the transfer roller 7. The transfer material P is introduced into the fixing device 8, and the unfixed toner image on the transfer material P surface is heated and pressed by the fixing device 8 to be heat-fixed on the transfer material P surface. The transfer material P exiting the fixing device 8 is conveyed by the discharge rollers 6 c and 6 d and discharged onto the discharge tray 9.

  6 is a conveying means. The transport means 6 includes a pip-up roller 6a, a registration roller 6b, discharge rollers 6c and 6d, transport rollers 6e to 6h, a gear mechanism (not shown) that connects these rollers 6a to 6h, and the gear mechanism. It includes a conveyance motor (not shown) that is driven.

(2) Fixing Device FIG. 3 is a cross-sectional side view of an example of the fixing device 8. FIG. 4 is a view of the fixing roller 21, the pressure roller 22, and the cleaning rollers 24 and 25 as viewed from the transfer material P discharge side. FIG. 5 is a vertical side view of the fixing roller 21 and the pressure roller 22.

  The fixing device 8 shown in the present embodiment includes a fixing roller 21, a pressure roller 22, a halogen heater (heating source) 23, cleaning rollers 24 and 25, and a thermistor 27 as temperature detecting means.

  The fixing roller 21 has a 2 mm thick silicon rubber elastic layer 21 b having heat resistance and low hardness around an elongated cylindrical iron core 21 a having an outer diameter of 46 mm and a thickness of 2 mm. The fixing roller 21 further includes a PFA resin release layer 21c having a thickness of 50 μm around the elastic layer 21b. Both ends of the metal core 21a are rotatably held by front and rear side plates (not shown) of the device frame 51 via bearings 31L and 31R.

  The halogen heater 23 provided inside the cored bar 21a of the fixing roller 21 is supported in a state in which the seal portions 23L and 23R at both ends are fixed to the front and rear side plates of the apparatus frame 51 via a heater holder (not shown). .

  The pressure roller 22 includes a silicon rubber elastic layer 22b having a heat resistance and a low hardness of 2 mm around a solid iron core 22a having an outer diameter of 44 mm and a thickness of 2 mm. The pressure roller 22 further includes a PFA resin layer 22c having a thickness of 50 μm around the elastic layer 22b. The pressure roller 22 is disposed below the fixing roller 21 so as to face the fixing roller 21 in parallel, and both ends of the cored bar 22a are rotatably held on the front and rear side plates of the apparatus frame 51 via bearings 32L and 32R. ing. Then, both ends of the cored bar 22a are pressed against the fixing roller 21 with a pressing force of 980 N by a not-shown pressure spring (pressure means). As a result, the surface of the pressure roller 22 is brought into contact with the surface of the fixing roller 21 to elastically deform the elastic layers 21b and 22b, thereby forming a nip portion (fixing nip portion) N having a predetermined width between the surface of the fixing roller 21. Yes.

  The thermistor 27 is provided at a substantially longitudinal center portion of the fixing roller 21 via a support member (not shown) provided on the front and back side plates of the apparatus frame 51 (approximately the central portion of the conveyance area of the transfer material P having the maximum size (FIG. 4)). Is arranged. As a result, the surface temperature of the fixing roller 21 can be accurately detected, and stable fixing performance can be ensured.

  The cleaning rollers 24 and 25 are each formed in a pipe shape from a metal material such as aluminum or a heat resistant resin material. The cleaning rollers 24 and 25 have a pipe thickness of 2 mm and an outer diameter of 10 mm. The cleaning roller 24 is disposed in parallel and opposite to the fixing roller 21, and both ends are rotatably held on the front and rear side plates of the apparatus frame 51 via bearings 33 </ b> L and 33 </ b> R. Then, both ends thereof are pressed against the fixing roller 21 with a pressing force of 19.6 N by a not-shown pressure spring (pressure means). As a result, the outer peripheral surface (surface) of the cleaning roller 24 is brought into contact with the surface of the fixing roller 21 and the elastic layer 21b of the fixing roller 21 is elastically deformed so that a cleaning nip portion Na having a predetermined width is formed between the surface of the fixing roller 21. Forming. The cleaning roller 25 is disposed to face the pressure roller 22 in parallel, and both ends thereof are rotatably held on the front and rear side plates of the apparatus frame 51 via bearings 34L and 34R. Both ends of the pressure roller 22 are pressed against the pressure roller 22 by a pressure of 19.6 N by a not-shown pressure spring (pressure means). As a result, the outer peripheral surface (surface) of the cleaning roller 25 is brought into contact with the surface of the pressure roller 22, and the elastic layer 22b of the pressure roller 22 is elastically deformed to thereby form a cleaning nip having a predetermined width with the surface of the pressure roller 22. Part Nb is formed.

  In the fixing device 8, the rotation drive control circuit (rotation drive control means) 41 rotates the fixing motor (drive source) M according to the drive command signal S 1 from the controller 200. The motor M rotates the rotation driving gear G provided on the cored bar 22a of the pressure roller 22 to rotate the pressure roller 22 in the arrow direction. The pressure roller 22 applies a rotational force to the fixing roller 21 through the nip portion N. As a result, the fixing roller 21 is driven to rotate in the direction of the arrow as the pressure roller 22 rotates. The cleaning roller 25 receives a rotational force from the pressure roller 22 through the cleaning nip portion Nb. As a result, the cleaning roller 25 is driven to rotate in the direction of the arrow as the pressure roller 22 rotates. On the other hand, the cleaning roller 24 receives a rotational force from the fixing roller 21 through the cleaning nip portion Na. As a result, the cleaning roller 24 is driven to rotate in the direction of the arrow as the fixing roller 21 rotates.

  On the other hand, the temperature control circuit (temperature control means) 41 turns on the power supply circuit (power supply means) 42 in response to the power supply command signal S 2 from the controller 200, and power is applied from the power supply circuit 42 to the heater 23. The heater 23 generates heat when electric power is applied to heat the fixing roller 21. The temperature of the fixing roller 21 is detected by the thermistor 27 and input to the temperature control circuit 41. The temperature adjustment control circuit 41 outputs a power supply control signal S3 to the power supply circuit 42 and performs on / off control of the power supply circuit 42, so that the temperature detected by the thermistor 27 becomes a predetermined temperature (target temperature). To control. In this embodiment, the power supply circuit 42 is controlled so that the temperature detected by the thermistor 27, that is, the surface temperature of the fixing roller 21 is about 190 ° C. The transfer material P carrying the unfixed toner image t in a state where the surface of the fixing roller 21 is adjusted to a predetermined temperature is introduced into the nip portion N by the entrance guide 52. The transfer material P is nipped and conveyed by the nip portion N, and the unfixed toner image t is heated and fixed on the transfer material P by being heated and pressurized during the conveyance process. As described above, the offset toner adhering to the surface of the fixing roller 21 during the transfer process of the transfer material P adheres to the surface of the cleaning roller 24 and is collected. Further, the offset toner adhering to the surface of the pressure roller 22 during the transfer process of the transfer material P adheres to the surface of the cleaning roller 25 and is collected. Then, the transfer material P that has exited the nip portion N is sent out from the fixing device 8 by the discharge roller 53. Separation claws 54 and 55 are provided on the side of the discharge roller 53 of the nip portion N. The separation claw 54 prevents the transfer material P from being wrapped around the fixing roller 21, and the separation claw 55 prevents the transfer material P from being wound around the pressure roller 22.

(3) Image contamination at the end of the transfer material P generated by the collected toner When the transfer material P is continuously printed in large quantities, the surface temperature of the cleaning rollers 24 and 25 may exceed about 150 ° C., which is the melting point of the toner. In that case, the toner adhering to the surface of the cleaning roller 24 melts and the reverse flow phenomenon of the toner adhering to the surface of the fixing roller 21 occurs. In addition, the toner adhering to the surface of the cleaning roller 25 also melts, and the backflow phenomenon of the toner adhering to the surface of the pressure roller 22 occurs. The toner flowing back to the surface of the fixing roller 21 and the surface of the pressure roller 22 is transferred to the large transfer material P when the transfer material P having a size larger than the size of the previous transfer material P is nipped and conveyed by the nip portion N. It becomes apparent as part dirt. In particular, in borderless printing, the toner transferred to the edge of the transfer material P tends to adhere to the surface of the fixing roller 21, and when borderless printing is performed continuously, the toner adheres to the surfaces of the fixing roller 21 and the pressure roller 22. Will be more. For this reason, image stains in the roller diameter cycle of the fixing roller 21 and the pressure roller 22 due to residual toner on the surface of the fixing roller 21 and the pressure roller 22 that cannot be collected by the cleaning rollers 24 and 25 become obvious.

(4) Borderless Printing Control Sequence Next, a borderless printing control sequence having a cleaning mode for collecting toner adhering to the surfaces of the cleaning roller 24 and the cleaning roller 25 will be described.

  This control sequence is stored in the memory of the controller 200. In the cleaning mode, cleaning paper (cleaning material) is used for the purpose of collecting toner collected by the cleaning rollers 24 and 25 (hereinafter referred to as collected toner). Two types of transfer materials having different sizes are used as cleaning paper. One is a transfer material used during borderless printing. The other is a transfer material of the maximum width size that can be used in the image forming apparatus 100. In order to distinguish between the transfer material P and the cleaning paper, the cleaning paper is denoted by Pc and Pcm.

  FIG. 6 is a flowchart of an example of a control sequence for borderless printing. FIG. 7 shows the toner adhering to the surfaces of the fixing roller 21, the pressure roller 22 and the cleaning rollers 24 and 25, the cleaning paper Pc of the transfer material P for borderless printing, and the cleaning paper of the maximum width size in borderless printing. It is explanatory drawing showing the relationship of Pcm.

  In the image forming apparatus 100, in a print standby state, a transfer material P having a predetermined size for borderless printing is stored in the feeding cassette 5. The size of the transfer material P is smaller than the maximum size transfer material that can be used in the image forming apparatus 100.

  In S1, the marginless printing signal described in the above section (1) is executed by taking in the marginless printing signal (starting of marginless printing).

In S2, the number K of marginless printed pages and the number L of accumulated marginless printed pages L are counted. In this embodiment, the number of printed pages is defined as the number of pages converted to A4 size per printed sheet. That is, one page is counted when a toner image of A4 size (210 mm × 297 mm = 62370 mm ² ) or less is formed on the surface of the photosensitive drum 1. Assume that two pages are counted when a toner image larger than the A4 size and smaller than the A3 size (420 mm × 297 mm = 124740 mm ² ) is formed. However, when duplex printing is performed on a transfer material of the same size, it is counted as two pages when a toner image of A4 size or smaller is formed. When a toner image larger than the A4 size and smaller than the A3 size is formed, it is counted as 4 pages. The size of the toner image is determined by the CPU of the controller 200 according to the size of the transfer material used. The counted print page number K and the cumulative print page number L are stored in the memory of the controller 200.

  In S3, it is determined whether or not the number K of marginless printed pages is 200 or more. When the number K of marginless printed pages is 200 or more, the process proceeds to S4, and when it is less than 200, the process proceeds to S6.

  In S4, in order to execute the first cleaning mode, borderless printing is temporarily interrupted, and at least one cleaning paper Pc is fed. That is, the drive of the rotation drive system of the photosensitive drum 1, the exposure device 3, the transport motor of the transport means 6, and the fixing motor M of the fixing device 8 is stopped, and borderless printing is temporarily interrupted. At this time, the surface temperature of the fixing roller 21 of the fixing device 8 is maintained at a temperature of approximately 180 ° C. (toner image heating temperature) during borderless printing based on the temperature detected from the thermistor 27. At the same time, the fixing motor M of the fixing device 8 is rotationally driven to rotate the fixing roller 21 and the pressure roller 22 idly for about 60 seconds. As a result, the toner collected by the cleaning rollers 24 and 25 can be forced to flow back to the surface of the fixing roller 21 and the surface of the pressure roller 22. In this way, as much of the recovered toner as possible that may cause image smearing due to backflow from the surfaces of the cleaning rollers 24 and 25 during borderless printing is made to flow back to the surface of the fixing roller 21 and the surface of the pressure roller 22. After that, the rotation drive system, the conveyance motor, and the fixing motor M are driven, and the cleaning paper Pc is conveyed from the inside of the feeding cassette 5 to the nip portion N via the transfer nip portion T and passed therethrough. When the cleaning paper Pc is nipped and conveyed at the nip portion N, the backflow toner on the surface of the fixing roller 21 and the surface of the pressure roller 22 adheres to the surface of the cleaning paper Pc (FIG. 7). Thereby, the toner collected on the surfaces of the cleaning rollers 24 and 25 can be collected by the cleaning paper Pc.

  During execution of the first cleaning mode, a message to that effect is displayed on a display panel (not shown) provided in the image forming apparatus 100 to give visual information to the user.

  In S5, after the cleaning paper Pc passes through the nip portion N, the number K of marginless printed pages is reset to zero, and the first cleaning mode is ended. That is, the rotation drive system, the conveyance motor, and the fixing motor M are stopped.

  In S1 to S5, since the transfer material P in the feeding cassette 5 used for borderless printing is used as the cleaning paper Pc, the user can collect the collected toner with the cleaning paper Pc without setting the cleaning paper Pc. As a result, the surfaces of the cleaning rollers 24 and 25, the surface of the fixing roller 21, and the surface of the pressure roller 22 are cleaned by the cleaning paper Pc.

  However, when the transfer material P carrying the unfixed toner image t enters the nip portion N in a posture inclined obliquely with respect to the recording material conveyance direction, the transfer material P extends over an area that is greater than the width of the transfer material P in the longitudinal direction of the nip portion N. The toner may adhere to the surface of the fixing roller 21 and the surface of the pressure roller 22. Thus, the toner adhering to the surface of the fixing roller 21 and the surface of the pressure roller 22 cannot be collected even when the cleaning paper Pc having the same width as the transfer material P is used.

  Therefore, by using the cleaning paper Pc having the maximum width in Step 6 and subsequent steps, the toner that cannot be recovered even when the cleaning paper Pc having the same width as the width of the transfer material P is used is recovered.

  In S6, borderless printing is resumed by driving the rotation drive system, the exposure device 3, the transport motor, and the fixing motor M. In S6, it is determined whether or not the cumulative count number L is 2000 or more. When the cumulative count number L is 2000 or more, the process proceeds to S7, and when it is less than 2000, the process proceeds to S10.

  In S7, the display panel displays the maximum width size of the cleaning paper Pcm. In this embodiment, a message is displayed so that the SRA3 size transfer material P is set in the feeding cassette 5 as the cleaning paper Pcm. If borderless printing is ongoing, borderless printing is temporarily suspended again and a message is displayed.

  In S8, after the message is displayed, the user sets the SRA3-sized cleaning paper Pcm in the feeding cassette 5 and performs an operation for driving the transport motor from an operation unit (not shown) provided in the image forming apparatus. The second cleaning mode is executed. That is, the cleaning paper Pcm is fed from the feeding cassette 5 to maintain the surface temperature of the fixing roller 21 of the fixing device 8 at a temperature of about 180 ° C. during borderless printing, and the fixing motor M is rotationally driven to rotate the fixing roller. 21 and the pressure roller 22 are idled for about 60 seconds. As a result, the toner collected by the cleaning rollers 24 and 25 is forced to flow back to the surface of the fixing roller 21 and the surface of the pressure roller 22. Thereafter, the rotational drive system of the photosensitive drum 1, the transport motor of the transport means 6, and the fixing motor M of the fixing device 8 are driven to transfer at least one or more cleaning paper Pcm from the feed cassette 5 to the transfer nip portion T. To the nip portion N and pass through. When the cleaning paper Pcm is nipped and conveyed at the nip portion N, the backflow toner on the surface of the fixing roller 21 and the surface of the pressure roller 22 adheres to the surface of the cleaning paper Pcm (FIG. 7). As a result, toner that cannot be recovered even when the cleaning paper Pc having the same width as the transfer material P is used can be recovered.

  In S9, after the cleaning paper Pcm is discharged to the discharge tray 9, the accumulated marginless printed page number L and the marginless printed page number K are reset to zero, and the second cleaning mode is terminated. That is, the rotation drive system, the conveyance motor, and the fixing motor M are stopped.

  In S10, a message is displayed on the display panel so as to reset the transfer material P originally used for borderless printing to the feeding cassette 5. When the user resets the transfer material P, the print standby state is entered. If borderless printing is temporarily interrupted, borderless printing is resumed.

  From the above control sequence, (A) Usually, the marginless printing transfer material P is fed to the nip portion N as the cleaning paper Pc by the automatic execution function. As a result, the adhering toner adhering to the surfaces of the rollers 21, 22, 24, and 25 can be collected at a position corresponding to the edge surface portion of the transfer material P for borderless printing. (B) The cleaning paper Pcm having the maximum width size is fed to the nip portion N only at a specific timing assuming that the transfer material P enters the nip portion N in an oblique posture. As a result, the adhered toner in the longitudinal direction region of each of the rollers 21, 22, 24, and 25 to which the toner can adhere can be collected. Further, by increasing the frequency of execution (A) to (B), it is possible to reduce the burden of performing the cleaning work by the user.

  According to this embodiment, the first cleaning mode in which the transfer material P being used for borderless printing is automatically fed as the cleaning paper Pc, and the user operation with the transfer material P having the maximum width size as the cleaning paper Pcm. And a second cleaning mode for feeding. Accordingly, the toner adhered to the surfaces of the rollers 21, 22, 24, and 25 can be collected well, and the transfer material P for borderless printing can be prevented from being stained, and at the same time, it is convenient for the user when using the image forming apparatus 100. Can also be increased.

  In this embodiment, the borderless printing control sequence in the fixing device 8 of the monochrome image forming apparatus 100 has been described. However, the control sequence includes no border in the fixing device 8 of the color image forming apparatus of yellow, magenta, cyan, and black. Applicable to printing control sequence. In this case, the amount of toner adhering to each roller of the fixing device is increased as compared with the monochrome image forming apparatus, but the marginless print page number K and the cumulative marginless print page number L that determine the timing of the first and second cleanings. The same effect can be obtained by optimizing the value of.

  In this embodiment, another example of the image forming apparatus will be described. Members and portions that are common to the image forming apparatus of Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted.

  The image forming apparatus of this embodiment is characterized in that a cleaning paper having a resin layer on the front and back surfaces is used as the maximum width size cleaning paper Pcm used in the second cleaning mode of the borderless printing control sequence. . Except for this point, the configuration is the same as that of the image forming apparatus of the first embodiment.

  The cleaning paper Pcm used in the image forming apparatus of the present embodiment has a resin layer mainly composed of a polyester resin on the front and back surfaces. By having the resin layers on the front and back surfaces, the affinity with the toner and the smoothness of the surface are improved. By increasing the affinity with the toner, the recovery rate of the toner adhering to each of the rollers 21, 22, 24, and 25 of the fixing device 8 is improved when the cleaning paper Pcm is fed. In addition, since the smoothness of the front and back surfaces of the cleaning paper Pcm increases, the contact area with the fixing roller 21 and the pressure roller 22 increases. As a result, more adhering toner on the surface of the fixing roller 21 and the surface of the pressure roller 22 can be collected by the cleaning paper Pcm.

  An example of a borderless printing control sequence in the image forming apparatus according to the present exemplary embodiment will be described below.

  When marginless printing is started as in the first embodiment, the number K of marginless printed pages and the number L of accumulated marginless printed pages are counted. If the number K of borderless printed pages is a certain value (for example, K ≧ 200) or more, borderless printing is temporarily suspended, and the transfer material used for borderless printing is fed as the cleaning paper Pc (first page). One cleaning mode). After that, borderless printing is resumed, and if the cumulative number of marginless printed pages L is a certain value (for example, L ≧ 2000), borderless printing is interrupted and cleaning paper is placed on the display cassette 5 on the display panel. Display a message to set. Here, the cleaning-dedicated paper is cleaning paper having the maximum width (SRA3 size) that can be used by the image forming apparatus, and is cleaning paper (for example, glossy paper) having resin layers on the front and back surfaces. The user sets cleaning-dedicated paper whose front and back surfaces are coated with a resin layer mainly composed of about 10 μm of polyester resin in the feeding cassette 5 and is operated by the user from the operation unit. As a result, the cleaning paper Pcm is fed from the feeding cassette 5.

  Thus, by periodically feeding the cleaning paper from the feeding cassette 5 in accordance with the borderless printing control sequence, the collection efficiency of the toner adhering to the surfaces of the rollers 21, 22, 24, 25 is increased. This further improves the cleaning performance.

  According to the present embodiment, in the second cleaning mode, the transfer material P having the maximum width size having the resin layers on the front and back surfaces is used as the cleaning paper Pcm, so that it adheres to the surfaces of the rollers 21, 22, 24, 25. The collected toner can be reliably recovered. This prevents the transfer material P from being smeared during borderless printing.

1 is a configuration model diagram of an example of an image forming apparatus. (A) is explanatory drawing showing the transfer area | region of the toner image to the transfer material by borderless printing, (b) is explanatory drawing showing the toner transcribe | transferred to the edge surface of the transfer material. It is a cross-sectional side model diagram of an example of a fixing device. FIG. 4 is a diagram of a fixing roller, a pressure roller, and a cleaning roller as viewed from a transfer material discharge side. It is a vertical side view model drawing of a fixing roller and a pressure roller. It is a flowchart of an example of a control sequence of borderless printing. FIG. 5 is an explanatory diagram illustrating a relationship between toner adhering to the surfaces of a fixing roller, a pressure roller, and a cleaning roller, cleaning paper for a marginless printing transfer material, and cleaning paper of a maximum width size in marginless printing.

Explanation of symbols

1: Photosensitive drum, 6: Conveying means, 7: Transfer device, 21: Fixing roller, 22: Pressure roller, 24, 25: Cleaning roller, 200: Print controller, P: Transfer material, Pc: Cleaning paper, Pcm : Maximum width of cleaning paper

Claims (3)

Conveying means for conveying a transfer material, an image carrier for carrying a toner image, a transfer means for transferring a toner image on the image carrier to a transfer material conveyed by the conveying means, and a nip portion for transferring the transfer material A rotating member that heats and fixes the toner image on the transfer material while nipping and conveying the toner, a collecting member that collects the toner attached to the rotating member, and a nip portion of the rotating member that collects the toner collected by the collecting member And a control unit having a cleaning mode for recovery by a cleaning material, and an image forming apparatus for transferring a toner image onto the transfer material by protruding the edge of the transfer material by the transfer device,
In the cleaning mode, at least one or more sheets are transferred by the transport unit according to the number of transfer materials on which the rotating body is held at the heating temperature of the toner image and the edges of the transfer material are protruded by transferring the toner image. A first cleaning mode in which the transfer material is conveyed as a cleaning material, and the rotating body is maintained at the heating temperature of the toner image and the edge of the transfer material is protruded to transfer the toner image to the accumulated number of transfer materials. An image forming apparatus comprising: a second cleaning mode in which a transfer material having a size in a longitudinal direction orthogonal to a transfer material conveyance direction larger than the cleaning material is conveyed as a cleaning material by a conveyance unit.   In the second cleaning mode, the cleaning material conveyed by the conveying means is a cleaning material having a maximum width size that can be used in the image forming apparatus in a longitudinal direction perpendicular to the transfer material conveyance direction. The image forming apparatus according to claim 1.   3. The image according to claim 1, wherein, in the second cleaning mode, the cleaning material conveyed by the conveying unit is a cleaning material having a resin layer on a surface on the rotating body side. Forming equipment.

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