JP2010139859A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the cleaning performance by preventing a rotation failure of a cleaning roller. <P>SOLUTION: This image forming device includes cleaning rollers 32a and 32b for removing toner adhering to a fixing roller for fixing a toner image transferred to a transfer material P. The cleaning roller 32a is constituted as a roller divided in the width direction orthogonal to a conveying direction of the transfer material. The cleaning rollers 32a and 32b have a region where cleaning regions contacting with the fixing roller overlap each other in the width direction. The end position of the width direction of the conveyed transfer material exists in the overlapping cleaning regions. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In the present invention, for example, a developer image (toner image) formed on an image carrier by an electrophotographic method is transferred to a transfer material, and then fixed to obtain a permanent image on the transfer material. The present invention relates to an image forming apparatus.

  There is known an electrophotographic image forming apparatus including a step of transferring a developer image (toner image) formed on the surface of a photosensitive drum as an image carrier onto a transfer material such as paper as a transfer medium. In an image forming apparatus, a transfer material is passed through a transfer portion formed at a contact portion between a photosensitive drum and a transfer member such as a transfer roller pressed against the photosensitive drum, and a transfer voltage is applied to the transfer member in accordance with this timing. Apply. The toner image on the surface of the photosensitive drum is transferred to a transfer material by the action of an electric field formed by the applied transfer voltage.

  As a color image forming apparatus, a configuration in which a plurality of image carriers are arranged in a line, toner images are sequentially formed on each image carrier, and the toner images are transferred directly to a transfer material or via an intermediate transfer member. Is common.

  Also, with the recent diversification of printer demand, there is a growing demand for borderless recording, particularly in color image forming apparatuses. Conventionally, the margin was cut after printing on a slightly larger transfer material. In order to simplify the margin cutting operation, there is an increasing need for so-called marginless recording in which an image is printed on the entire surface of the transfer material without creating a margin margin around the transfer material in advance.

  An example of an electrophotographic full-color image forming apparatus that supports borderless recording will be briefly described with reference to FIG.

  The image forming apparatus includes four color image forming units (image forming stations 10) 10a, 10b, 10c, and 10d of yellow (Y), magenta (M), cyan (C), and black (K). A photosensitive drum 11 (11a to 11d) is provided as an image carrier.

  To form an image, first, the surface of the photosensitive drum 11 (11a to 11d) of each station is uniformly charged by the primary charging roller 12 (12a to 12d). Then, image exposure is performed by color-separating the document by the laser exposure unit 13 (13a to 13d), and an electrostatic latent image corresponding to the separated color of the document is formed on the surface of the photosensitive drum 11. The latent image is developed with minus toner by the developing device 14 (14a to 14d) to form toner images of respective colors on the surface of the photosensitive drum 11. Each color toner image on the photosensitive drum 11 is sequentially superposed on the intermediate transfer belt 1 by a primary transfer roller 15 (15a to 15d) to which a primary transfer voltage is applied from a primary transfer power supply 16 (16a to 16d) to perform primary transfer. To do.

  Incidentally, the transfer residual toner adhering to the surface of the photosensitive drum 11 after the transfer is removed by the drum cleaner 17 (17a to 17d), and is used for the next image formation.

  Thereafter, the four color toner images on the intermediate transfer belt 1 are collectively collected by the secondary transfer roller 2 to which the secondary transfer voltage is applied from the secondary transfer power source 21 to the transfer material P conveyed to the intermediate transfer belt 1. Secondary transfer. Then, the transfer material P that has been subjected to the secondary transfer is conveyed to the fixing device 3, and is pressed and heated by the fixing roller 30 and the pressure roller 31 to melt and mix the four color toners, and is fixed on the transfer material P. A full color image is formed on the transfer material P. On the other hand, the transfer residual toner remaining on the surface of the intermediate transfer belt 1 that has finished the secondary transfer is removed by the belt cleaner 4.

  When performing borderless recording on the transfer material P, the mask area for determining the recording area for the transfer material P is a width having a predetermined length for each of the front end portion, rear end portion, left end portion, and right end portion of the transfer material P. The area is larger than that of the transfer material P by the amount of the additional area having the thickness. Then, an image including the part of the added area is formed on the photosensitive drum, and this is transferred to the transfer material P to achieve borderless recording.

  By performing image formation by such a method, when the transfer material P passes through the secondary transfer nip portion, variations in relative positions in the transport direction and the scanning direction between the transfer material P and the image on the intermediate transfer belt 1 are detected. Even if this occurs, good marginless recording can be performed. The transport direction is the process direction of the image forming apparatus, and the scanning direction is a direction perpendicular to the transport direction.

  In addition, a part of the toner in the added area outside the transfer material P at the time of the secondary transfer adheres to the secondary transfer roller 2, and this adhered toner causes the back of the transfer material P to become dirty. Therefore, it is removed by the secondary transfer roller cleaner 22 in contact with the secondary transfer roller 2.

  On the other hand, the toner is transferred not only on the surface but also on a part of the paper edge surface of the surrounding four sides surrounding the end portion on the transfer material P after the secondary transfer process in the secondary transfer portion. When the transfer material P enters the fixing device 3, the toner on the paper edge remains unfixed at the fixing nip portion, and a phenomenon occurs in which the toner is offset onto the surfaces of the fixing roller 30 and the pressure roller 31. . When the offset toner adheres to the surface of each roller, the front and back surfaces of the transfer material P are stained. In order to deal with such a toner offset problem of the fixing device, the toner adhering to the fixing roller 30 and the pressure roller 31 is collected and accumulated by a cleaning roller. Then, it has been proposed to clean the cleaning roller itself by discharging it onto the cleaning paper when the predetermined number of sheets is reached (see Patent Document 1). For this reason, cleaning rollers 32 and 33 are in contact with the surfaces of the fixing roller 30 and the pressure roller 31, respectively, and using these, the toner adhering to the surfaces of both rollers is collected.

JP 2003-57985 A

  However, in the method of Patent Document 1, the contact resistance of the cleaning roller increases due to the toner collected by the cleaning roller as a cleaning member, and there is a problem that a load is imposed on the rotation of the cleaning roller. Further, the cleaning performance may be deteriorated due to the rotational load of the cleaning roller.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus capable of improving the cleaning performance of a cleaning member in an image forming apparatus capable of performing borderless recording.

  A typical means of the present invention for solving the above problems is to transfer a toner image formed on an image carrier to a transfer material in an image forming apparatus having a borderless recording mode for forming a borderless image on the transfer material. An image forming unit for fixing, a fixing unit for fixing the toner image transferred to the transfer material, and the fixing unit in a width direction perpendicular to the conveying direction of the transfer material in order to remove the toner attached to the fixing unit. A plurality of cleaning members in contact with each other, wherein at least one cleaning member is divided in the width direction, and the divided cleaning member and another cleaning member overlap in the width direction. It has a cleaning area, and the end position in the width direction of the transferred transfer material is in the overlapping cleaning area.

  According to the present invention, the cleaning member is divided so that it is brought into contact with the fixing means in a plurality of contact areas, and both ends in the width direction of the transfer material are cleaned by the cleaning member. For this reason, malfunction of the cleaning member can be prevented and the cleaning performance can be improved.

  Next, an image forming apparatus according to the best mode for carrying out the present invention will be described with reference to the drawings.

[First Embodiment]
An image forming apparatus 100 according to the first embodiment of the present invention is shown in FIG.

  The maximum size of the transfer material that can be used is SRA3 (width 320 mm × length 450 mm). The process speed is 117mm / sec. The recording speed of A4 horizontal feed can be 24 sheets / minute.

  The image forming apparatus 100 of the present embodiment is connected to a personal computer 101 via a cable 102 as shown in FIG. The image data is transmitted from the personal computer 101 to the image forming apparatus 100 via the cable 102. The image forming apparatus 100 forms a borderless recording mode, which is a first image forming mode for performing borderless recording, and a second image forming for performing a recording with a normal border on the transfer material P. It has a function to form an image by a bordered recording mode which is a mode.

<Configuration and operation of image forming apparatus>
This image forming apparatus is configured as a four-drum, intermediate transfer type full-color printer. As shown in FIG. 1, the image forming apparatus includes four color image forming portions (image forming stations 10) 10a, 10b, and 10c of yellow (Y), magenta (M), cyan (C), and black (K). , 10d, and a transfer device including the intermediate transfer belt 1 and a fixing device 3.

  Each image forming station (toner image forming means) 10a, 10b, 10c, 10d is configured as an image forming unit, and photosensitive drums 11a, 11b, 11c, 11d, which are image carriers, are rotatably installed in the direction of the arrows. ing. Primary charging rollers 12a, 12b, 12c, and 12d for uniformly charging the surfaces of the photosensitive drums are disposed on the outer peripheral surfaces of the photosensitive drums 11a, 11b, 11c, and 11d, respectively. Laser exposure devices 13a, 13b, 13c, and 13d that expose the surface of the photosensitive drum with laser light modulated in accordance with the image signal are disposed on the downstream side in the rotation direction of the photosensitive drum. Further, on the downstream side, each color electrostatic latent image formed on the surface of the photosensitive drum formed by laser exposure is developed using corresponding yellow, magenta, cyan, and black toners to form a toner image. Developing units 14a, 14b, 14c, and 14d are arranged.

  Primary transfer rollers 15a, 15b, 15c, and 15d that form a primary transfer portion together with the photosensitive drum are opposed to each other at a position (transfer position) between the photosensitive drums 11a, 11b, 11c, and 11d with the intermediate transfer belt 1 interposed therebetween. ing. Primary transfer power supplies 16a, 16b, 16c, and 16d are connected to the primary transfer rollers 15a, 15b, 15c, and 15d as primary transfer power supplies, and variable primary transfer voltages Vy, Vm, Vc, and Vk are applied to the primary transfer rollers 15a, 15b, 15c, and 15d, respectively. .

  The intermediate transfer belt 1 is stretched and installed on three rollers, a driving roller 1a, a tension roller 1b, and a secondary transfer counter roller 1c. The intermediate transfer belt 1 passes through the image forming stations 10a to 10d and passes through the photosensitive drums 11a to 11d. 11d is placed in contact. The intermediate transfer belt 1 is driven to rotate in the direction of the arrow in the figure by a driving roller 1a. Drum cleaners 17a, 17b, 17c, and 17d are installed downstream of the primary transfer rollers 15a, 15b, 15c, and 15d of the photosensitive drums 11a, 11b, 11c, and 11d. A belt cleaner 4 is disposed on the surface of the intermediate transfer belt 1.

  The image forming operation of the image forming apparatus configured as described above will be described using the yellow image forming station 10a as an example. The photosensitive drum 11a of the yellow image forming station 10a has a photoconductive layer formed on the surface of an aluminum cylinder, and the surface is uniformly negatively charged by the primary charging roller 12a in the process of rotating in the direction of the arrow. (Charging potential = −600 V). Next, image exposure is performed by the laser exposure device 13a (surface potential after exposure = −200 V), and an electrostatic latent image corresponding to the yellow image component of the document is formed on the surface of the photosensitive drum 11a. This latent image is developed using negatively charged yellow toner by the developing device 14a, and the latent image is visualized as a yellow toner image.

  The obtained yellow toner image is primarily transferred onto the intermediate transfer belt 1 by applying a primary transfer voltage from the primary transfer power supply 16a to the primary transfer roller 15a. After the transfer, the transfer residual toner adhering to the surface of the photosensitive drum 11a is removed by the drum cleaner 17a, and used for the next image formation.

  The above-described image forming operation is performed at a predetermined timing in each of the image forming stations 10a to 10d, and the toner images on the photosensitive drums 11a to 11d are sequentially overlapped on the intermediate transfer belt 1 in the respective primary transfer portions to be primary. Transcript. In the full color mode, the toner images are sequentially transferred to the intermediate transfer belt 1 in the order of yellow, magenta, cyan, and black. In the single color or 2-3 color mode, the toner images of the necessary colors are as described above. Transcribed in the same order. Thereafter, the four color toner images on the intermediate transfer belt 1 are transferred to the secondary transfer counter roller 1c in which the secondary transfer roller 2 is grounded with the intermediate transfer belt 1 interposed therebetween as the intermediate transfer belt 1 rotates in the arrow direction. Is moved to the secondary transfer portion that is in contact with. In this secondary transfer portion, a secondary transfer voltage is applied from the secondary transfer power source 21 to the secondary transfer roller 2 on the transfer material P supplied at a predetermined timing by the feeding roller 7. Next is transferred. Then, the transfer material P on which the unfixed toner image that has passed through the secondary transfer nip portion is conveyed to the fixing device 3 and is heated and pressurized to form a permanent fixed image. Further, the transfer material P discharged from the fixing device 3 is discharged to a discharge tray 8 outside the device. The intermediate transfer belt 1, the secondary transfer counter roller 1c, and the secondary transfer roller 2 constitute a transfer unit.

  Next, the transfer material cassette 5 will be described with reference to FIG. The transfer material P is placed in the transfer material cassette 5 by a pair of longitudinal position restricting plates 52, and the photosensitive drums 11a to 11d, the intermediate transfer belt 1, the fixing roller 30, the pressure roller 31, and a cleaning roller 32a as a cleaning member. 32b, 33a, 33b and the longitudinal center are aligned and accumulated. The fixing roller 30 and the pressure roller 31 constitute a pair of fixing rollers. The transfer material P taken out from the transfer material cassette 5 has two photosensitive drums 11a to 11d, an intermediate transfer belt 1, a fixing roller 30, a pressure roller 31, and cleaning rollers 32 and 33 in a state where the longitudinal centers thereof are aligned. It is inserted into the next transfer nip portion and the fixing nip portion. That is, the image forming apparatus according to the present embodiment has a so-called central reference configuration. The transfer material P taken out from the transfer material cassette 5 by the pickup roller pair 51 is transferred at a predetermined timing synchronized with the toner image on the intermediate transfer belt 1 by the transport roller 61 of the feeding device 6 and the feeding roller 7. It is inserted into the next transfer section. As shown in FIG. 4, the transfer material P of the present embodiment is centered in the longitudinal direction during conveyance until it is discharged from the transfer material cassette 5 to the discharge tray 8 due to the dimensional tolerance of the transfer material cassette 5 and the accuracy of the feeding device 6. On the other hand, it is conveyed with a runout of 1.5mm (plus or minus).

  Here, when borderless recording is performed on the transfer material P in the image forming apparatus, the mask region E is located at the front end, rear end, left end, and right end of the transfer material P as shown in FIG. The area is larger than the transfer material P by the extra area B having a width of 2 mm each. Note that the mask area E is used to determine a recording area in the transfer material P when recording with a normal edge is performed. Then, an image including the image portion of the added area B is formed on the photosensitive drum, and this is transferred onto the transfer material P via the intermediate transfer belt 1 to obtain a borderless recorded image.

  Note that a part of the toner in the added region outside the transfer material P during the secondary transfer adheres to the secondary transfer roller 2. The adhered toner is removed by the secondary transfer roller cleaner 22 that is in contact with the secondary transfer roller 2.

  On the other hand, on the transfer material P that has finished the secondary transfer process in the secondary transfer portion, as shown in FIG. 6, not only the surface but also a paper edge surface that is a cut surface portion of the surrounding four sides surrounding the end portion. The toner is also transferred to a part of the toner. When the transfer material P enters the fixing device 3, as shown in FIG. 7, the toner on the paper edge remains unfixed at the fixing nip portion, and on the surfaces of the fixing roller 30 and the pressure roller 31. The phenomenon of offsetting occurs. When the offset toner adheres to the surface of each roller, the transfer material P becomes dirty on the front and back surfaces. Accordingly, cleaning rollers 32 and 33 are in contact with the fixing roller 30 and the pressure roller 31, respectively, and using these, the toner attached to the surfaces of both rollers is collected.

  In this way, a full-color image without a border on which the four color toner images are transferred and fixed is obtained on the transfer material P.

<Constituent parts of image forming apparatus>
In this embodiment, a negatively chargeable OPC drum having a diameter of 30.6 mm is used as the photosensitive drum 11, and a charging voltage in which an AC component is superimposed on a DC component is applied to the primary charging roller 12, regardless of the environment. The surface of the body drum 11 is uniformly charged to about −600V. The laser exposure unit 13 has a near-infrared laser diode having a wavelength of 760 nm and a polygon mirror that scans the photosensitive drum 11 with laser light. The surface potential of the photosensitive drum 11 is lowered to −200 V at the exposure unit. Then, an electrostatic latent image having this as an image portion is formed.

  The developing device 14 is a developing type developing device using a non-magnetic toner (non-magnetic one-component developer), and uses a polymer toner having a core / shell structure particle size of 6 μm containing wax as a non-magnetic toner. ing. This is coated and carried on the surface of the developing sleeve by an application roller, and the thickness of the toner layer is regulated by an elastic blade as the developing sleeve rotates, and is conveyed to the developing unit facing the photosensitive drum 11. The toner on the developing sleeve is attached to the exposure portion of the electrostatic latent image on the photosensitive drum 11 by the developing voltage obtained by superimposing the AC component on the DC component applied to the developing sleeve, and the latent image is reversely developed. is there.

  The primary transfer roller 15 is formed by covering an 8 mm diameter cored bar with a conductive rubber layer of EPDM (ethylene propylene diene rubber) in the longitudinal direction to form a diameter of 16 mm. Connected to the primary transfer power supply 16. The roller hardness of the primary transfer roller 15 is 35 ° in Asker C, and its resistance value is 1 × 10 6 Ω.

  The secondary transfer roller 2 is a roller having an outer diameter of 22.1 mm, composed of an aluminum core having a diameter of 14.0 mm, a silicon rubber layer having a thickness of 4 mm, and a fluororesin layer having a surface thickness of 100 μm. The resistance of the roller is adjusted to 1 × 10 8 Ω by adjusting the resistance of silicon rubber and fluororesin. The hardness of the secondary transfer roller 55 is 45 ° (ASKER-C). The secondary transfer roller 2 also has a core metal connected to a secondary transfer power source 21 via a power supply spring.

  As the secondary transfer roller cleaner 22, a urethane rubber blade is used. Each of the driving roller 1a, the tension roller 1b, and the secondary transfer counter roller 1c is made of an aluminum conductive roller having a diameter of 32 mm, and the cored bar portion is grounded via a power supply spring. The intermediate transfer belt 1 is a single-layer seamless endless belt made of polyimide resin, the resistance of which is adjusted by carbon dispersion, and has a thickness of 75 μm and a circumference of 1115 mm. In accordance with JIS-K6911, in order to obtain good contact between the electrode and the surface of the belt, a conductive rubber is used as an electrode, and then the volume resistance of the intermediate transfer belt is measured using an Advanced 8300 R8340 resistance meter. The rate ρv and the surface resistivity ρs were measured. Then, a value of ρv = 5 × 10 8 Ωcm was obtained when 100 V was applied for 10 seconds.

  The tension of the intermediate transfer belt 1 stretched around the three drive rollers 1a and the tension rollers 1b and 1c is 6 kgf. The distance between the driving roller 1a and the tension roller 1b is 500 mm, and the primary transfer portion constituted by the photosensitive drum 11 and the primary transfer roller 15 in each image forming station 10 is an intermediate between the driving roller 1a and the tension roller 1b. They are arranged on the transfer belt 1 at equal intervals. Each primary transfer roller 15 is brought into contact with the back surface of the intermediate transfer belt 1 with a pressure of 8.5 N by springs provided at both ends.

  The fixing roller 30 is provided with a heat resistant and low hardness 2 mm silicon rubber elastic layer on an iron core bar having an outer diameter of 46 mm and a thickness of 2 mm, and further a PFA resin layer having a thickness of 50 μm is provided thereon. In addition, the inside is heated by a heater. The surface temperature of the fixing roller 30 is detected by a temperature detection element in contact with the fixing roller 30, and the temperature control circuit intermittently operates the heater so that the surface temperature becomes a predetermined temperature (for example, 180 ° C).

  On the other hand, the pressure roller 31 that rotates in pressure contact with the fixing roller 30 is provided with a silicon rubber elastic layer having a heat resistance and a low hardness of 2 mm on an iron core bar having an outer diameter of 44 mm and a thickness of 2 mm. It has a structure in which a PFA resin layer having a thickness of 50 μm is provided thereon. However, there is no heater inside. The pressure roller 31 is brought into contact with the fixing roller 30 with a pressure of 980 N by springs provided at both ends.

<Cleaning means>
Next, the configuration of the cleaning means for removing the toner adhering to the fixing roller 30 and the pressure roller 31 for cleaning will be described.

  The cleaning unit of the present embodiment includes cleaning rollers 32 a and 32 b that are a plurality of cleaning members that clean the fixing roller 30, and cleaning rollers 33 a and 33 b that are a plurality of cleaning members that clean the pressure roller 31. Each of the cleaning rollers 32a, 32b and 33a, 33b is a metal roller made of aluminum, one of which is configured in a straight shape and the other in a divided shape.

  That is, the cleaning rollers 32a and 33a as the first cleaning members are configured as rollers divided in the width direction of the transfer material (hereinafter simply referred to as “width direction”) orthogonal to the transfer material conveyance direction. The cleaning rollers 32a and 33a are disposed in the vicinity of the fixing nip, and are configured as rollers having an outer diameter of 10 mm and an axial diameter of 6 mm. On the other hand, the cleaning rollers 32b and 33b as the second cleaning members are straight-shaped rollers that are not divided in the width direction, and are configured as rollers having an outer diameter of 10 mm.

  The fixing roller 30 and the pressure roller 31 are brought into contact with a pressure of 19.6 N during borderless recording by a contact / separation mechanism (not shown), and separated during bordered recording. The positional relationship in the longitudinal direction is as shown in FIG. The portion of the cleaning roller 32a that contacts the fixing roller 30 (cleaning region) is divided into seven portions 32a1, 32a2, 32a3, 32a4, 32a5, 32a6, and 32a7. Similarly, the cleaning roller 33a is also divided into seven portions 33a1, 33a2, 33a3, 33a4, 33a5, 33a6 and 33a7. The cleaning rollers 32 a and 32 b have overlapping ranges XL 1, XL 2, XL 3, XR 1, XR 2, and XR 3 in the width direction position range in contact with the fixing roller 30. The cleaning rollers 33a and 33b are provided with overlapping ranges YL1, YL2, YL3, YR1, YR2, and YR3 in the width direction position range in contact with the pressure roller 31. These portions are overlapping widths for collecting toner in the same range with respect to the fixing roller 30 and pressure roller 31 portions corresponding to the paper edge surface in the traveling direction of the transfer material P, and transfer for performing borderless recording. The paper edge surface in the traveling direction of the material P is arranged to be guided by the overlapping width.

  That is, the cleaning rollers 32a and 33a are in contact with the fixing roller 30 and the pressure roller 31 in a plurality of contact areas divided in the width direction. The cleaning rollers 32a and 32b have a plurality of overlapping ranges (overlapping cleaning regions by the cleaning rollers 32a and 32b) where a plurality of width direction position ranges divided in the width direction overlap. The plurality of overlapping cleaning areas include the paper edge surface (end position in the width direction of the transfer material) of the transfer material P in the process direction (conveyance direction). The same applies to the cleaning rollers 33a and 33b.

  In this embodiment, A5-P, A4-P, A4-L, A3-P, LTR-P, LTR-L, LGL-P, and LDR-P can be used as the size of the transfer material P capable of borderless recording. Therefore, the overlapping width of the cleaning rollers is arranged corresponding to the paper edge surface in the traveling direction of each size.

<About cleaning control>
Here, cleaning control of the cleaning rollers 32a and 32b and 33a and 33b in the image forming apparatus of the present embodiment will be described.

  In the image forming apparatus of this embodiment, the number of pages on which borderless recording has been performed is counted by a printer controller (not shown) attached to the image forming apparatus. The number of normal recording pages with borders is not counted. The cleaning rollers 32a, 32b and 33a, 33b are in contact with the fixing roller 30 and the pressure roller 31 during borderless recording, and the paper edge surface of the transfer material P adhered to the surfaces of the fixing roller 30 and the pressure roller 31. Collect the toner. The portion corresponding to the paper edge surface of the transfer material P in the traveling direction has a particularly large amount of adhesion. For this reason, the toner collection force is increased by the overlapping range (overlapping cleaning region) XL1, XL2, XL3, XR1, XR2, XR3 and YL1, YL2, YL3, YR1, YR2, YR3 of the cleaning rollers 32a, 32b and 33a, 33b. Yes.

  As the recording medium, a memory (RAM, rewritable ROM, etc.) in the printer controller is used. When borderless recording is performed using a transfer material of A4 size or smaller, it is counted as one page, and when it is performed using a transfer material of A4 size or larger and A3 size or smaller, it is counted as two pages. However, when double-sided printing is performed on the same sheet, when borderless recording is performed using a transfer material of A4 size or less, it is counted as 2 pages, and transfer material of A4 size or more and A3 size or less is used. Is counted as 4 pages.

  When the number of marginless recording pages counted in this way reaches 1000 pages in total, a message prompting the start of cleaning control is displayed on the personal computer 101. Specifically, a message is displayed to set a single sheet of plain SRA3 size paper as the cleaning paper in the transfer material cassette 5 and to operate the personal computer to start the cleaning control.

  When the user follows this message, a sequence for recollecting the toner on the cleaning roller onto the cleaning paper is activated. In the image forming apparatus of this embodiment, first, idling is performed for 60 seconds in a heater control state at 180 ° C. during the recording operation. Thereby, the toner on each cleaning roller is forced to flow back onto the fixing roller and the pressure roller. That is, first, as much toner as possible on each cleaning roller that may cause image smearing due to backflow is caused to flow back to the surface of the fixing roller and the pressure roller. Thereafter, the cleaning paper is automatically conveyed from the inside of the transfer material cassette 5 to the fixing nip and passed therethrough, whereby the toner is collected again on the cleaning paper.

<Recordable transfer material size>
In the image forming apparatus of the present embodiment, the user can set the size information of the transfer material set in the transfer material cassette 5 on the personal computer 101. When the transfer material is transported through the image forming apparatus, if the size in the scanning direction is the “width” of the transfer material and the size in the process direction is the “length” of the transfer material, transfer that can be set by this image forming apparatus The width of the material ranges from 100 mm to 320 mm and the length ranges from 148 mm to 450 mm. In the image forming apparatus of the present embodiment, when the user transmits image data from the personal computer 101, it is possible to set whether the recording operation is performed in the marginless recording mode or the recording operation is performed in the margined mode. When the borderless recording mode is used, a final image recorded on the entire surface of the transfer material P is obtained, and when the bordered recording mode is used, the leading end portion and the trailing end portion of the transfer material P are used. A final image in which a margin of 5 mm width is formed at the left end and the right end is obtained.

  Here, in this image forming apparatus, the width of the maximum transfer material operable in the marginless recording mode is limited to 297 mm, and the maximum width of the transfer material operable in the margined recording mode is limited to 320 mm. Yes. 297 mm corresponds to the width when the A3 size transfer material is passed, and 320 mm corresponds to the width when the SRA3 size transfer material is passed. Settings contrary to this cannot be performed by the user on the personal computer 101. That is, when the width of the transfer material set in the transfer material cassette 5 is 297 mm or less, image data can be transmitted by specifying either the marginless recording mode or the margined recording mode. However, if the width is larger than 297 mm, only image data can be transmitted by specifying the bordered recording mode.

  Further, as described above, in the present image forming apparatus, the cleaning paper set and used in the transfer material cassette 5 when performing the cleaning control is a white SRA3 size plain paper having a width of 320 mm.

  In the image forming apparatus of the present embodiment, as shown in FIG. 8, the overlapping ranges XL1, XL2, XL3, and XR1, XR2, XR3 of the width direction position range of the cleaning roller are the fluctuation width of the transfer material P. This is determined from the area B to be added in FIG. The same applies to the overlapping ranges YL1, YL2, YL3, and YR1, YR2, YR3. The transfer width of the transfer material P is 1.5 mm (plus or minus), and the additional region B is larger than the transfer width of the transfer material P so that a borderless image can be obtained even if the transfer material P is shaken by the transfer. It is set. In this embodiment, it is 2.0 mm. Therefore, the minimum overlap width of the cleaning rollers is sufficient if the transfer width range of the transfer material P is 3.0 mm and the added region is larger than B2.0 mm to 5.0 mm.

  Further, since the contact area of the cleaning rollers 32a and 33a is divided as shown in FIG. 8, the contact area with the fixing roller 30 and the pressure roller 31 is about 75% as compared with a normal straight roller. Therefore, the contact resistance can be greatly reduced.

  As described above, in the image forming apparatus according to this embodiment, at least one cleaning roller having a divided configuration is used. Therefore, by creating an overlapping width with respect to the edge of the transfer material in the conveyance direction, the contact resistance of the cleaning roller can be reduced and good cleaning performance can be obtained, while the cleaning control of the fixing device is minimized in the marginless recording. In addition, the transfer material can be prevented from being soiled.

  In this embodiment, the cleaning roller is provided for both the fixing roller 30 and the pressure roller 31, but the cleaning roller may be provided for only one of the rollers.

[Second Embodiment]
The image forming apparatus according to the second embodiment of the present invention has the configuration shown in FIG. 1 as with the image forming apparatus according to the first embodiment. Further, the operation and components of the image forming apparatus are the same as those of the image forming apparatus of the first embodiment.

  The image forming apparatus of this embodiment is characterized in that the minimum overlapping width of the cleaning rollers is larger than the sum of the maximum skew amount of the transfer material and the added region.

  Also in the image forming apparatus of this embodiment, the overlapping width of the cleaning rollers is arranged so as to correspond to the edge of the transfer material in the conveyance direction. The maximum transfer material that can be operated in the borderless recording mode has a width of 297 mm (corresponding to the width when A3 size transfer material is fed), and the maximum transfer material that can be operated in the bordered recording mode has a width of 320 mm ( This corresponds to the width when the SRA3 size transfer material is passed.

  The skew amount of the transfer material in the second embodiment of the present invention will be described.

  The transfer material P is placed in the transfer material cassette 5 by a pair of longitudinal position regulating plates 52, and the photosensitive drums 11a to 11d, the intermediate transfer belt 1, the fixing roller 30, the pressure roller 31, and the cleaning rollers 32a, 32b, 33a, 33b and the longitudinal center are aligned and accumulated. As a result, the transfer material P taken out from the transfer material cassette 5 is aligned with the photosensitive drum 11, the intermediate transfer belt 1, the fixing roller 30, the pressure roller 31, and the cleaning rollers 32 and 33 in the longitudinal center. It is inserted into the secondary transfer nip portion and the fixing nip portion. That is, the image forming apparatus according to the present embodiment has a so-called central reference configuration. The transfer material P taken out from the transfer material cassette 5 by the pickup roller pair 51 is transferred at a predetermined timing synchronized with the toner image on the intermediate transfer belt 1 by the transport roller 61 of the feeding device 6 and the feeding roller 7. It is inserted into the next transfer section. At that time, it is ideal that the transfer material is always conveyed without any deviation, but in actuality, the transfer material may be conveyed obliquely due to the waist and the state of the transfer material and the wear of the conveying roller and feeding roller. When the skew feeding amount increases, the transferability of the transfer material becomes unstable, the image is defective due to insufficient transfer at the secondary transfer section, or the image contacts the transport path due to the transfer material jumping, and further at the fixing nip section. Twist and wrinkles may occur in the transfer material. It is necessary to design so as to fit a certain amount of skew so as not to cause such a problem. As shown in FIG. 9, the transfer material P of the present embodiment is conveyed with a skew amount of 0.45% (plus or minus) with reference to the leading end of the transfer material P until it is discharged from the transfer material cassette 5 to the discharge tray 8, The LDR (18 inch length) size is 1.95 mm or less.

In the image forming apparatus of this embodiment,
The overlapping ranges (overlapping cleaning regions) XL1, XL2, XL3 and XR1, XR2, XR3 of the cleaning roller width direction position range are determined from the maximum skew amount of the transfer material P and the addition region B of FIG. The same applies to the overlapping ranges (overlapping cleaning regions) YL1, YL2, YL3, and YR1, YR2, YR3. The maximum skew of the transfer material P is 1.95 mm (plus or minus) from the longest LDR size of borderless recordable transfer materials, and the transfer material P is skewed in the additional area B. However, the setting is larger than the fluctuation width of the transfer material P so that a borderless image can be obtained. In this embodiment, it is 2.0 mm. Accordingly, the minimum overlapping width of the cleaning rollers may be larger than 5.9 mm from the addition area B 2.0 mm, ie, the range width of the maximum skew amount of the transfer material P is 3.9 mm.

As described above, in the image forming apparatus according to this embodiment, at least one cleaning roller having a divided configuration is used, and even when the transfer material is skewed, the cleaning roller is always on the edge in the conveyance direction. Make the overlapping width of. Therefore, it is possible to reduce the contact resistance of the cleaning roller and obtain a good cleaning property, and to prevent the transfer material from being soiled while minimizing the cleaning control of the fixing device in borderless recording [Third Embodiment].
The image forming apparatus according to the third embodiment of the present invention has the configuration shown in FIG. 1 as with the image forming apparatus according to the first embodiment. Further, the operation and components of the image forming apparatus are the same as those of the image forming apparatus of the first embodiment.

  A characteristic feature of the image forming apparatus of the present embodiment is that the plurality of cleaning rollers are each divided and have an overlapping width.

  Also in the image forming apparatus of this embodiment, the overlapping width of the cleaning rollers is arranged so as to correspond to the edge of the transfer material in the conveyance direction. The maximum transfer material that can be operated in the borderless recording mode has a width of 297 mm (corresponding to the width when A3 size transfer material is fed), and the maximum transfer material that can be operated in the bordered recording mode has a width of 320 mm ( This corresponds to the width when the SRA3 size transfer material is passed.

  FIG. 10 shows a cleaning roller according to a third embodiment of the present invention.

  The cleaning rollers 32a and 33a as the first cleaning member and the cleaning rollers 32b and 33b as the second cleaning member of the present embodiment are metal rollers made of aluminum divided in the width direction. Each roller has an outer diameter of 10 mm and a shaft diameter of 6 mm. The fixing roller 30 and the pressure roller 31 are brought into contact with a pressure of 19.6 N during borderless recording by a contact / separation mechanism (not shown), and separated during bordered recording.

  The positional relationship in the width direction of the cleaning rollers 32a, 32b, 33a, 33b is as shown in FIG. The contact area of the cleaning roller 32a is divided into five parts 32a1, 32a2, 32a3, 32a4 and 32a5. The contact area of the cleaning roller 32b is divided into four parts 32b1, 32b2, 32b3 and 32b4.

  Similarly, the contact area of the cleaning rollers 33a and 33b is divided into five parts 33a1, 33a2, 33a3, 33a4 and 33a5 and four parts 33b1, 33b2, 33b3 and 33b4.

  The cleaning rollers 32a, 32b and 33a, 33b are arranged so that the non-cleaning region by the first cleaning rollers 32a, 33a becomes the cleaning region by the second cleaning rollers 32b, 33b in the width direction.

  The cleaning rollers 32a and 32b are provided with overlapping ranges (overlapping cleaning regions) XL1, XL2, XL3, XR1, XR2, and XR3 as overlapping widths for collecting toner in the same range in the width direction with respect to the fixing roller 30. . Further, the cleaning rollers 33a and 33b are provided with YL1, YL2, YL3, YR1, YR2, and YR3 as overlapping widths for collecting toner in the same range as the pressure roller 31. The paper edge surface (end position in the width direction of the transfer material) of the transfer material P that performs the borderless recording with respect to the pressure roller 31 is arranged to be guided by the overlapping width. In this embodiment, A5-P, A4-P, A4-L, A3-P, LTR-P, LTR-L, LGL-P, and LDR-P can be used as the size of the transfer material P capable of borderless recording. Therefore, the overlapping width of the cleaning rollers is arranged corresponding to the paper edge surface in the traveling direction of each size.

As described above, in the image forming apparatus of the present embodiment, as shown in FIG. 10, the overlapping ranges XL1, XL2, XL3 and XR1, XR2, XR3 (YL1, YL2, YL3, and YR1, YR2,. YR3) is determined from the runout width or maximum skew amount of the transfer material P and the addition region B in FIG. 5 as in the first and second embodiments. Since the area B to be added is 2.0 mm, in the case of the transfer width of the transfer material P from the first embodiment, the overlapping width of the cleaning roller only needs to be larger than 5.0 mm, and the maximum skew of the transfer material P from the second embodiment. In the case of quantity, the overlap width of cleaning rollers should be larger than 5.9mm,
In this embodiment, the cleaning rollers 32b and 33b are divided as shown in FIG. 8 in addition to the cleaning rollers 32a and 33a. For this reason, since the contact area between the fixing roller 30 and the pressure roller 31 is about 60% as compared with a normal straight roller, the contact resistance can be further reduced as compared with the first embodiment.

  As described above, in the image forming apparatus according to the present embodiment, a plurality of divided cleaning rollers are used to create a width that overlaps the edge of the transfer material in the conveyance direction. For this reason, the contact resistance of the cleaning roller can be reduced and good cleaning performance can be obtained, and contamination of the transfer material can be prevented while minimizing the cleaning control of the fixing device in borderless recording.

  Further, by adopting a configuration in which each cleaning roller is divided in the width direction, it is possible to reduce the rotational load and perform cleaning reliably.

1 is a diagram illustrating a configuration of an image forming apparatus of the present invention. It is a figure which shows the connection of an image forming apparatus and an image transmitter. It is a perspective view of a transfer material cassette. It is a figure which shows the runout width of conveyance of a transfer material. It is a figure which shows the addition area | region with respect to a transfer material. It is a figure which shows the adhesion state of paper cover toner. It is a figure which shows the offset toner on a fixing roller and a pressure roller. It is a figure which shows the structure of the cleaning roller of 1st Embodiment. It is a figure which shows the skew feeding amount of a transfer material. It is a figure which shows the structure of the cleaning roller of 3rd Embodiment. It is a figure which shows the structure of the conventional image forming apparatus.

Explanation of symbols

30… Fixing roller
31… Pressure roller
32a, 32b ... Cleaning roller
33a, 33b ... cleaning roller P ... transfer material XL1, XL2, XL3, XR1, XR2, XR3 ... overlapping range of cleaning roller YL1, YL2, YL3, YR1, YR2, YR3 ... overlapping range of cleaning roller

Claims (6)

In an image forming apparatus having a borderless recording mode for forming a borderless image on a transfer material,
Image forming means for transferring the toner image formed on the image carrier to a transfer material;
Fixing means for fixing the toner image transferred to the transfer material;
In order to remove the toner adhering to the fixing unit, the fixing unit has a plurality of cleaning members in contact with the fixing unit in a width direction orthogonal to a transfer material conveyance direction, and at least one cleaning member is divided in the width direction. Cleaning means,
Have
The divided cleaning member and another cleaning member have a cleaning region that overlaps in the width direction, and an end position in the width direction of a transfer material to be conveyed is in the overlapping cleaning region. An image forming apparatus. The length in the width direction of the overlapping cleaning region is
2. The image according to claim 1, wherein the transfer material is longer than a sum of a maximum length that the transfer material swings in the width direction during conveyance and a maximum length of a toner image that protrudes from the transfer material to form an image. Forming equipment. The length in the width direction of the overlapping cleaning region is
2. The method according to claim 1, wherein the transfer material is longer than a sum of a maximum skew amount when the transfer material is skewed during conveyance and a maximum length of a toner image formed by protruding from the transfer material. Image forming apparatus. The fixing unit includes a rotating fixing roller, and a pressure roller that presses the transfer material against the fixing roller.
The image forming apparatus according to claim 1, wherein the cleaning unit is provided in each of the fixing roller and the pressure roller.   The said cleaning means has the 1st cleaning member divided | segmented in the said width direction, and the 2nd cleaning member which is not divided | segmented in the said width direction, The any one of Claim 1 thru | or 4 characterized by the above-mentioned. The image forming apparatus described in 1. The cleaning means includes a first cleaning member and a second cleaning member that are each divided in the width direction,
5. The image formation according to claim 1, wherein, in the width direction, a non-cleaning region by the first cleaning member becomes a cleaning region by the second cleaning member. 6. apparatus.

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