JP2013210486A - Cleaning device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device having an elastic cleaning plate that brings the elastically deformable leading end part thereof into contact with the external surface of a transfer belt passed through a transfer part, the transfer belt being formed by dispersing resin particles composed of polytetrafluoroethylene (PTFE), and that is able to restrict degradation in cleaning performance, which arises as a result of falling and denting of PTFE resin, formed on the external surface of the transfer belt passed through the elastic cleaning plate, and to provide an image forming apparatus.SOLUTION: A cleaning device comprises: an elastic cleaning plate rotated so as to carry a developer image, constituted from developer with external additive attached thereto, to a transfer section, which transfers the developer image to a target recording material, by holding the developer image thereof, and configured to remove residual developer by bringing the elastically deformable leading end part thereof into contact with the external surface of the transfer belt passed through the transfer part, the transfer belt being formed from resin particles composed of polytetrafluoroethylene; and a metal cleaning plate configured to bring the elastically-non-deformable leading end part thereof into contact with the external surface of the transfer belt in a position downstream of the elastic cleaning plate in the rotating direction of the transfer belt.

Description

  The present invention relates to a cleaning device and an image forming apparatus.

  In an image forming apparatus such as a printer, a copying machine, or a facsimile that forms an image composed of a developer, a developer image developed with the developer is formed on an image carrier such as a photoconductor, and then the developer image is formed. In some cases, an intermediate transfer method is employed in which the toner image is temporarily transferred to the outer surface of an intermediate transfer belt that rotates and then secondarily transferred to a recording material such as recording paper. In addition, an image forming apparatus that employs this intermediate transfer method is generally equipped with a cleaning device that removes unnecessary materials such as developer remaining on the outer surface after the secondary transfer of the intermediate transfer belt is completed and cleans it. Has been.

  Conventionally, as such a cleaning device or an image forming apparatus equipped with the cleaning device, for example, a plate-shaped crane blade that contacts the outer surface after the secondary transfer of the rotating intermediate transfer belt is completed, A cleaning device including a plate-shaped scraper that contacts an outer surface on the downstream side of the cleaning blade in the rotational direction of the intermediate transfer belt is known (Patent Document 1). Patent Document 1 shows that the plate-like craning blade is made of a flexible material such as rubber or resin.

JP 2011-123384 A

  The present invention rotates after passing through a transfer portion that holds a developer image and transfers it to a recording material, and then passes through a transfer portion of a transfer belt in which resin particles made of polytetrafluoroethylene (PTFE) are dispersed. The PTFE resin formed on the outer surface of the transfer belt that has passed through the elastic cleaning plate is used as a cleaning device having an elastic cleaning plate that removes residual developer by bringing the elastically deformed tip into contact with the outer surface of the transfer belt. Provided is a cleaning device capable of suppressing the deterioration of the cleaning performance caused by the depression or the PTFE resin film, and using the cleaning device, the streak-like image defect caused by the deterioration of the cleaning performance is provided. An image forming apparatus capable of forming an image with suppressed generation is provided.

The cleaning device of this invention (A1)
A developer image composed of a developer with an external additive is held on the outer surface and rotated so as to be conveyed to a transfer portion to be transferred to a recording material, and resin particles made of polytetrafluoroethylene are dispersed. An elastic cleaning plate that removes the remaining developer by contacting the elastically deformed tip to the outer surface of the transfer belt after passing through the transfer portion;
A metal cleaning plate is provided on the outer surface at a position downstream of the elastic cleaning plate in the rotation direction of the transfer belt.

  The cleaning device of the invention (A2) is the cleaning device of the invention A1, wherein the metal cleaning plate has a contact load with respect to the outer surface of the transfer belt in a range of 4.9 N / m to 49.0 N / m. It is something that is installed.

The image forming apparatus of this invention (B1)
An image forming apparatus for forming a developer image developed with a developer coated with an external additive on an image carrier;
The developer image formed on the image holding body of the image forming apparatus is rotated so as to be conveyed to a secondary transfer portion that is held on the outer surface and transferred to a recording material, and resin particles made of polytetrafluoroethylene are dispersed. An intermediate transfer belt,
An elastic cleaning plate that removes residual developer by contacting a tip portion that is elastically deformed to the outer surface of the intermediate transfer belt after passing through the secondary transfer portion, and the elastic cleaning plate in the rotational direction of the transfer belt And a cleaning device provided with a metal cleaning plate for bringing the tip portion that does not elastically deform into contact with the outer surface of the downstream side position.

  The image forming apparatus of the invention (B2) is the image forming apparatus of the invention B1, wherein the metal cleaning plate in the cleaning device has a contact load with respect to the outer surface of the transfer belt of 4.9 N / m or more and 49.0 N / m. It is installed in the following range.

  According to the cleaning device of the invention A1, compared with the case where the configuration of the invention is not provided, it is caused by the falling recess of the PTFE resin or the PTFE resin film formed on the outer surface of the transfer belt that has passed through the elastic cleaning plate. It is possible to suppress the deterioration of the cleaning performance that occurs.

  In the cleaning device of the invention A2, the effect of the invention A1 can be obtained more reliably without damaging the outer surface of the transfer belt as compared with the case where the configuration of the invention is not provided.

  According to the image forming apparatus of the invention B1, the PTFE resin drop-off depression or the PTFE resin film formed on the outer surface of the intermediate transfer belt that has passed through the elastic cleaning plate is compared with the case where the configuration of the invention is not provided. The deterioration of the cleaning performance of the cleaning device that occurs due to this is suppressed, and it is possible to form an image that suppresses the generation of streak-like image defects due to the deterioration of the cleaning performance.

  In the image forming apparatus of the invention B2, the effect of the invention B1 can be obtained more reliably without damaging the outer surface of the intermediate transfer belt as compared with the case where the configuration of the invention is not provided.

1 is an explanatory diagram showing an overview of an image forming apparatus according to Embodiment 1 and the like. FIG. 2 is an explanatory diagram conceptually showing a part (image forming device or the like) in the image forming apparatus of FIG. 1. FIG. 2 is a cross-sectional explanatory view schematically showing a configuration of an intermediate transfer belt used in the image forming apparatus of FIG. 1. It is sectional drawing which shows the belt cleaning apparatus used for the image forming apparatus of FIG. It is explanatory drawing which shows the principal part of the belt cleaning apparatus of FIG. It is explanatory drawing which shows typically the state of an effect | action of the elastic cleaning board and metal cleaning board in the belt cleaning apparatus of FIG. FIG. 3 schematically shows the state of the intermediate transfer belt in FIG. 3, (a) is a sectional explanatory view showing a state immediately after its manufacture (new article), and (b) is a sectional explanatory view showing a state in an initial stage of use. FIG. 4 schematically shows the state of the intermediate transfer belt after passing through a belt cleaning device without a metal cleaning plate or the belt cleaning device of FIG. 4, and (a) shows that a PTFE resin particle drop-out depression and a film are formed on the outer surface of the belt. Cross-sectional explanatory drawing which shows the state made, (b) is a cross-sectional explanatory drawing which shows the state in the stage further used from the state of (a). It is a cross-sectional explanatory view schematically showing the state of the intermediate transfer belt after passing through a belt cleaning device without a metal cleaning plate. FIG. 4 schematically shows the state of the intermediate transfer belt after passing through the belt cleaning device of FIG. 4, wherein (a) shows a state in which an external additive or the like is supplemented into a drop-out depression of PTFE resin particles formed on the outer surface of the belt. Cross-sectional explanatory drawing shown, (b) is a cross-sectional explanatory drawing showing the state of the PTFE resin film and the like at the stage of further use from the state of (a). It is a graph which shows the conditions and result of the evaluation test of a drum cleaning apparatus.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described with reference to the drawings.

[Embodiment 1]
1 to 4 show the cleaning device and the image forming apparatus according to the first embodiment. FIG. 1 shows an outline of the image forming apparatus, FIG. 2 shows a main part (image forming apparatus) in the image forming apparatus, FIG. 3 shows a part of an intermediate transfer belt in the image forming apparatus, and FIG. The structure of the cleaning apparatus and its peripheral part is shown.

  The image forming apparatus 1 according to the first embodiment is configured as a color printer, for example. As shown in FIG. 1, the image forming apparatus 1 has an apparatus main body 10 composed of a support structure material, an exterior material, and the like, and a developer (colored or the like is given inside the apparatus main body 10. A plurality of image forming devices 20 that form developer images developed with fine powder 18, and a recording sheet as an example of a recording material that holds the developer images formed by the respective image forming devices 20. An intermediate transfer device 30 for transfer to the intermediate transfer device 19, a paper supply device 40 for accommodating and transporting the required recording paper 19 to be supplied to the intermediate transfer device 30, and a recording paper 19 on which the developer image has been transferred by the intermediate transfer device 30. A fixing device 45 for fixing the toner image is arranged.

  The image forming apparatus 20 includes four image forming apparatuses 20Y, 20M, and 20C that respectively form developer images of four colors of yellow (Y), magenta (M), cyan (C), and black (black: K). , 20K. These four image forming devices 20 (Y, M, C, K) are arranged in a state of being arranged in series in the internal space of the housing 10. Each image forming device 20 (Y, M, C, K) has a substantially common configuration as shown below.

  Each image forming device 20 (Y, M, C, K) includes a photosensitive drum 21 that rotates in a direction indicated by an arrow A as shown in FIGS. 1 and 2, and around this photosensitive drum 21, The following devices are mainly arranged. The main devices are a charging device 22 for charging an image holding surface (outer peripheral surface) on which the image of the photosensitive drum 21 can be formed to a required potential, and image information (signal) on the charged outer peripheral surface of the photosensitive drum 21. The exposure device 23 that forms an electrostatic latent image having a potential difference (for each color) by irradiating light based on the above and the developer 18 of the corresponding color (Y, M, C, K). A developing device 24 (Y, M, C, K) that develops a developer image that is a visible image by developing, and a primary transfer device 25 that transfers the developer image to the intermediate transfer device 30 (intermediate transfer belt). And a drum cleaning device 26 that removes deposits such as the developer 18 that remains and adheres to the image holding surface of the photosensitive drum 21 after the transfer.

  The photosensitive drum 21 is formed by forming an image holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material on the peripheral surface of a cylindrical or columnar substrate to be grounded. It receives power and rotates in the direction indicated by the arrow. The charging device 22 is a non-contact type charging device in which a charging current is applied to a discharge wire arranged with a predetermined interval on the image holding surface of the photosensitive drum 21 and charged by corona discharge. A contact-type charging device including a contact member such as a charging roll that is disposed in contact with an image holding surface and is supplied with a charging bias. As the charging bias, when the developing device 24 performs reversal development, a voltage or current having the same polarity as the charging polarity of the toner supplied from the developing device is supplied.

  The exposure device 23 irradiates light (dotted line with arrows) configured according to image information input to the image forming apparatus 1 onto the image holding surface of the photosensitive drum 21 after being charged, and electrostatically It forms a latent image. As the exposure device 23, a non-scanning type exposure device configured using a light emitting diode and an optical component or a scanning type configured using an optical component such as a semiconductor laser and a polygon mirror is used. The exposure apparatus 23 performs image processing necessary for an image processing apparatus (not shown) on information on an image to be printed input to the image forming apparatus 1, and transmits image signals of respective color components obtained after the processing. It has become so.

  As shown in FIG. 2, the developing device 24 (Y, M, C, K) supplies the developer 15 of any one of the four colors accommodated in the container-like device main body 24a with stirring and conveying (not shown). After being agitated by a member and triboelectrically charged to a required polarity, a developing bias is supplied, held on a rotating developing roll 24b, and supplied to a developing area facing the photosensitive drum 21, and formed on the photosensitive drum 21. The latent image is developed. As the developer 15, for example, a two-component developer composed of toner and carrier or a one-component developer composed only of toner is used. The primary transfer device 25 is a contact type transfer device including a primary transfer roll that rotates in contact with the image holding surface of the photosensitive drum 21 and is supplied with a primary transfer bias. As the primary transfer bias, a DC voltage or the like having a polarity opposite to the charging polarity of the developer 15 is applied from a transfer power supply unit (not shown).

  The drum cleaning device 26 includes a container-shaped main body 26 a, a rotating brush 26 b that rotates with the hair material in contact with the outer peripheral surface of the photosensitive drum 21 after the primary transfer, and a rotating brush 26 b on the outer peripheral surface of the photosensitive drum 21. The cleaning plate 26c is disposed so as to be in contact with a required pressure at a position downstream of the contact portion with a required pressure, and scrapes off adhering substances such as the developer 15 and adheres to the hair material of the rotary brush 26. A flicker 26d for scraping off the developer 15 to be scraped, a recovery transport member 26e such as a screw auger for recovering the developer 15 scraped off from the hair material of the rotary brush 26 and transporting it to a recovery system (not shown). . As the cleaning plate 26c, a plate-like member made of flexible rubber, resin or the like is used.

  As shown in FIG. 1 and the like, the intermediate transfer device 30 is arranged so as to exist at a position below each image forming device 20 (Y, M, C, K). The intermediate transfer device 30 includes an intermediate transfer belt 31 that rotates in a direction indicated by an arrow B while passing through a primary transfer position between the photosensitive drum 21 and the primary transfer device 25 (primary transfer roll), and an intermediate transfer belt 31. A plurality of support rolls 32a to 32d for holding the transfer belt 31 in a desired state from the inner surface thereof and rotatably supporting the transfer belt 31, and an outer surface (image holding surface) of the intermediate transfer belt 31 supported by the support roll 32d. A secondary transfer device 35 that rotates in contact with the pressure of the developer, and developer and paper dust that remains on the outer surface (outer peripheral surface / image holding surface) of the intermediate transfer belt 31 after passing through the secondary transfer device 35 and adheres to it. The belt cleaning device 5 is mainly composed of a belt cleaning device 5 that removes unnecessary materials such as the like and cleans them. Of the plurality of support rolls 32a to 32d that support the intermediate transfer belt 31, the support roll 32a is configured as a drive roll, and the support roll 32c is configured as a tension applying roll.

  As shown in FIG. 3, the intermediate transfer belt 31 has a releasability with respect to a toner image on a belt base material 310 in which a resistance adjusting agent such as carbon black is dispersed in a synthetic resin such as a polyimide resin or a polyamide resin. An endless belt in which resin particles 4 made of polytetrafluoroethylene (PTFE) are dispersed is used for the purpose of giving (in other words, reducing the adhesion to the toner image). In the intermediate transfer belt 31, resin particles 4 made of PTFE are dispersed so as to be present at least on the surface layer portion 312 of the belt base material 310 (resin existing in a state exemplified by reference numeral 4 a in FIG. 3). particle). The intermediate transfer belt 31 has a surface roughness (ten-point average roughness: Ra) of the outer surface 31a from the viewpoint of ensuring an improvement in transfer efficiency of the toner image from the intermediate transfer belt 31 to the recording paper 19. Is a value smaller than 0.5, and the static friction coefficient of the outer surface 31a is preferably smaller than 1.0.

  Such an intermediate transfer belt 31 is manufactured, for example, by forming a surface layer in which resin particles 4 made of PTFE are dispersed on the outer surface of the belt base material 310. The surface layer is prepared by, for example, preparing a polyamic acid solution in which resin particles 4 made of PTFE, carbon black, and the like are dispersed as a layer forming material, and applying the layer forming material to the outer surface of the belt base material 310. It is formed by drying the film. Here, as the layer forming material comprising the polyamic acid solution, for example, a polyimide resin obtained by imidizing a mixture of a polyamic acid solution in which carbon black is dispersed and a polyamic acid solution in which fluororesin particles are dispersed is mixed. Can be used. In addition, the intermediate transfer belt 31 may be obtained by, for example, adding a PTFE resin to the forming material of the belt base material 310 and molding it. Also in the intermediate transfer belt 31 having this structure, the PTFE resin particles are unevenly distributed in the surface layer side portion of the belt substrate 310.

  The resin particles 4 made of PTFE have an average particle size of about 200 to 250 nm. Incidentally, the average particle size of the resin particles 4 is smaller than the average particle size (for example, 6 μm) of the toner particles of the developer used in this embodiment. The amount of the PTFE resin added to the belt base material 310 is preferably in the range of 0.2% to 30%, more preferably in the range of 1% to 15%. When the addition amount is less than 0.2%, there is a problem that the adhesion force of the intermediate transfer belt 31 to the toner image increases and the transfer efficiency decreases. On the other hand, when it exceeds 30%, there is a problem that the belt is warped and deformed due to thermal contraction when the belt is cooled in the manufacturing process of the intermediate transfer belt 31.

  The secondary transfer device 35 includes a drive roll 37a in which an endless secondary transfer belt 36 rotates in contact with the outer surface (image holding surface) of the intermediate transfer belt 31 supported by the support roll 32d with a predetermined pressure. Then, it is configured to be applied to one or a plurality of driven rolls 37b and rotate in a predetermined direction. A secondary transfer bias is supplied to the support roll 32d (or the secondary transfer belt) from a transfer power supply unit (not shown). As the secondary transfer bias, a DC voltage or the like indicating the same polarity (or opposite polarity) as the charging polarity of the developer 18 is supplied. As the secondary transfer belt 36, for example, a belt made of a synthetic resin such as a polyimide resin or a polyamide resin is used.

  The belt cleaning device 5 is disposed at a required position on the outer surface portion of the intermediate transfer belt 31 that exists between the secondary transfer device 35 and the support roll 32a as a drive roll. In the first embodiment, as shown in FIG. 1, the intermediate transfer belt 31 is disposed so as to exist in the vicinity of the upstream side in the rotational movement direction B from the position supported by the support roll 32 a of the intermediate transfer belt 31. Details of the belt cleaning device 5 will be described later.

  The paper feeding device 40 is disposed so as to exist at a position below the intermediate transfer device 30. The paper feeding device 40 is a single (or plural) paper container 41 that accommodates recording papers 19 of a desired size and type, and a sending device that feeds the recording paper 19 from the paper container 41 one by one. 42 is mainly configured. The fixing device 45 rotates inside the housing 46 in the direction indicated by the arrow and is heated by heating means so that the surface temperature is maintained at a predetermined temperature. A pressurizing rotator 48 which is rotated in contact with a predetermined pressure in a state substantially along the axial direction is installed.

  In addition, the apparatus main body 10 includes a plurality of paper transport rolls between the paper feeding device 40 and the secondary transfer position of the intermediate transfer device 30 (the portion where the intermediate transfer belt 31 and the secondary transfer device 35 are in contact). A supply conveyance path composed of pairs 43a, 43b, 43c,... And a conveyance guide material is provided. Further, between the secondary transfer device 35 and the fixing device 45, a belt type paper transporting device for transporting the recording paper 19 after the secondary transfer to the fixing device 45 is installed. Further, on the discharge side of the fixing device 45, a discharge conveyance path composed of a plurality of conveyance roll pairs 43d and 43d and a conveyance guide material is provided. In addition, a discharge storage unit for storing the recording paper 19 after image formation discharged from the discharge conveyance path is provided outside the apparatus main body 10.

  Further, the developer (toner) 15 used in the developing device 24 is provided with the following external additive. As the external additive, inorganic fine particles and organic fine particles can be used. Among them, silica, titania, alumina, cerium oxide, strontium titanate, calcium carbonate, magnesium carbonate, and calcium phosphate inorganic fine particles, fluorine Organic resin fine particles including resin fine particles, silica-containing resin fine particles, and nitrogen-containing resin fine particles are preferable. The surface of the external additive is a surface of a silane compound, a silane coupling agent, a silicone oil or the like for performing a hydrophobization treatment. You may perform the surface treatment using a processing agent. The particle size of the external additive is arbitrarily selected according to the purpose, and for example, a large particle size and a small particle size can be used in combination. In particular, when a developer 15 having a small particle diameter is used, at least one external additive having a large particle diameter of 0.1 μm or more may be used in order to prevent blocking between the developers. desirable. The average particle size of the external additive is generally 1 μm or less, and preferably in the range of 0.01 to 1 μm. If the average particle size exceeds 1 μm, for example, the particle size distribution of the finally obtained developer particles becomes wide, or external additives released from the developer particles are generated, which is not appropriate.

  A basic image forming operation by the image forming apparatus 1 is performed as follows. Here, an image forming operation pattern (full color) for forming a full color image composed of the four color toner images using all of the four image forming devices 20 (Y, M, C, K). Mode).

  When the image forming apparatus 1 is instructed to request an image forming operation (printing), in each of the four image forming apparatuses 20 (Y, M, C, K), first, each photosensitive drum 21 rotates in the direction of arrow A, Each charging device 22 charges the image holding surface of each photosensitive drum 21 to a required polarity (negative polarity in the first embodiment) and a potential. Subsequently, the exposure device 23 emits light on the charged surface of the photosensitive drum 21 based on the image data separated into the color components (Y, M, C, K) transmitted from the image processing device 27. Exposure is performed by irradiating light to form an electrostatic latent image of each color component composed of a required potential difference.

  Next, each developing device 24 (Y, M, C, K) is charged to a required polarity (negative polarity in the first embodiment) with respect to the electrostatic latent image of each color component formed on each photosensitive drum 21. Each color (Y, M, C, K) developer 18 (toner in the case of a two-component developer) is supplied and electrostatically adhered. Thereby, one of four color (Y, M, C, K) toner images is formed on the outer peripheral surface of the photosensitive drum 21 in each image forming device 21.

  Next, the four-color developer images formed by the image forming devices 20 (Y, M, C, K) are rotated by the primary transfer devices 25 in the direction of arrow B of the intermediate transfer device 30. The image is primarily transferred so as to be superimposed on 31 in order. After the primary transfer is completed, the outer peripheral surface of the photosensitive drum 21 is cleaned by the drum cleaning device 26 to prepare for the next image forming process. Subsequently, the intermediate transfer device 30 holds the toner image primarily transferred to the intermediate transfer belt 31 and conveys it to the secondary transfer position, and then conveys the toner image from the paper feeding device 40 through the supply conveyance path to the secondary transfer position. Secondary transfer is performed collectively on the sheet 19 by the secondary transfer device 35. After the secondary transfer is completed, the intermediate transfer belt 31 has its outer surface cleaned by the belt cleaning device 5 to prepare for the next intermediate transfer step.

  Finally, the recording paper 19 on which the toner image has been secondarily transferred is peeled off from the intermediate transfer belt 31 and then conveyed by the paper conveying device 44 and introduced into the fixing device 45, where necessary fixing processing ( The toner image is fixed by heating and pressurization. Then, the sheet 19 after the fixing is completed is discharged to the outside of the apparatus main body 10 through the discharge conveyance path and stored in the discharge storage portion in the image forming operation only for forming an image on one side. .

  With the above operation, the image forming apparatus 1 outputs the recording paper 19 on which a full-color image formed by combining four color developer images is formed.

  Next, the belt cleaning device 5 will be described.

  As shown in FIGS. 1 and 4, the belt cleaning device 5 has a box-shaped device main body 50 having an upper surface facing the intermediate transfer belt 31, and the device main body 50 includes an elastic cleaning plate 6, a metal The main components such as the cleaning plate 7, the rotating brush 8, and the recovery conveyance member 9 are arranged.

  The elastic cleaning plate 6 is a scraping member that mainly contacts the outer surface of the intermediate transfer belt 31 and scrapes off the developer adhering to the outer surface. This elastic cleaning plate 8 has a substantially rectangular elastic plate 61 made of an elastically deformable material such as rubber or resin, for example, and the elastic plate 61 performs intermediate transfer at a front end portion 61a which is one end on the long side. The belt 31 is in contact with the outer surface of the belt 31 and is supported by the support member 62 at the rear end, which is the other end on the long side. Further, the position of the outer surface portion of the intermediate transfer belt 31 in contact with the elastic cleaning plate 6 is stabilized at the position of the inner surface (inner peripheral surface) of the intermediate transfer belt 31 facing the position in contact with the elastic cleaning plate 6. A back support roll 65 is provided for support.

  As shown in FIG. 5 and the like, the elastic cleaning plate 6 has a free end of the elastic plate 61 and a tip portion 61a (corner portion) that is elastically deformed as required over the width direction of the outer surface of the intermediate transfer belt 31. It is fixed in a state of being exposed to the upper surface opening of the apparatus main body 50 via the support member 62 so that the contact can be made at the contact angle θ1. The width direction of the outer surface of the intermediate transfer belt 31 is a direction orthogonal to the rotational movement direction B, and corresponds to, for example, the direction of the rotation axis of the support roll 32a. The tip 61a that is elastically deformed is a tip having a characteristic that can be elastically deformed so that the corner of the tip 61a contacting the intermediate transfer belt 31 follows the moving direction of the belt 31 (see FIG. 6). .

  Specifically, the elastic cleaning plate 6 has an elastic plate 61 having a thickness in the range of 1.0 to 3.0 mm and substantially the same length as the width of the intermediate transfer belt 31 as an outer surface of the belt 31. Is set so that the contact load with respect to the intermediate transfer belt 31 is in the range of 4.9 N / m or more and 49.0 N / m or less. The contact contact weight F6 at this time is, for example, the amount of biting α of the elastic plate 61 with respect to the intermediate transfer belt 31 (the distance entering the inner side from the outer surface of the belt when no intermediate transfer belt is assumed) or its free It is set by adjusting the length Lf6 (the length of the portion not supported by the support member 62), the hardness of the material, and the like.

  The metal cleaning plate 7 is located outside the belt 31 at a position downstream of the contact start position at which the elastic cleaning plate 6 (the elastic plate tip 61a) starts to contact the intermediate transfer belt 31 in the rotational movement direction B of the belt 31. It arrange | positions on required conditions so that the surface may be contacted. As a result, the metal cleaning plate 7 functions as a second scraping member that finally scrapes off a small amount of developer that has not been scraped off from the outer surface of the intermediate transfer belt 31 by the elastic cleaning plate 6. As will be described later, it also functions as a member that removes the PTFE resin film formed on the outer surface of the intermediate transfer belt 31 and supplements the film or the removed part of the PTFE resin with an external additive of the developer.

  The metal cleaning plate 7 has a substantially rectangular metal plate 71 made of a metal such as a stainless steel plate, and the metal plate 71 is an outer surface of the intermediate transfer belt 31 at a tip portion 71a which is one end on the long side. Is supported by the support member 72 at the rear end which is the other end on the long side. Further, as shown in FIG. 5 and the like, the metal cleaning plate 7 has a free end of the metal plate 71 and a tip end portion 71a (a corner portion thereof) that is not elastically deformed on the outer surface of the intermediate transfer belt 31. It is fixed in a state where it is exposed to the upper surface opening of the apparatus main body 50 via the support member 72 at the other end so as to contact at θ2. The metal cleaning plate 7 according to the first embodiment is installed so that the front end portion 71a of the metal plate 71 comes into contact with the portion that starts to be supported by the support (drive) roll 32a of the intermediate transfer belt 31.

  Specifically, the metal cleaning plate 7 has a thickness of 0.05-0. A metal plate 71 having a length in the range of mm and approximately the same as the length in the width direction of the intermediate transfer belt 31 is set so that the contact angle θ2 with the outer surface of the belt 31 is 10 to 40 degrees. The contact load F7 with respect to the transfer belt 31 is set to be in the range of 4.9 N / m to 49.0 N / m. The contact weight F7 at this time adjusts, for example, the biting amount β (mm) of the metal plate 71 with respect to the intermediate transfer belt 31 and its free length Lf7 (the length of the portion not supported by the support member 72). Is set by The significance of specifying the contact load on the metal cleaning plate 7 in the above numerical range will be described later.

  The developer 15 b and the like scraped off by the metal cleaning plate 7 is dropped and collected in a container-like developer collecting unit 55 formed in the apparatus main body 50. Reference numeral 56 in FIG. 4 is a plurality of rib plates formed at a predetermined interval at the upper entrance of the developer recovery portion 55.

  The rotating brush 8 is formed with conductive bristle material 82 extending radially from the center of rotation of the core material 81 on the peripheral surface of the conductive core material 81 that also serves as a rotating shaft, and is entirely rolled. It consists of a shape. The rotating brush 8 is housed in a state where the entire rotating brush 8 exists above the mounting recess 52 of the apparatus main body 50, the bristle material 82 comes into contact with the outer surface of the intermediate transfer belt 31, and the core material 81 The intermediate transfer belt 31 is disposed along the width direction.

  The bristle material 82 of the rotary brush 8 contacts along the belt width direction at a position on the outer surface of the intermediate transfer belt 31 that is upstream of the contact start position of the elastic cleaning plate 68 in the rotation direction B of the belt 31. . As this hair material 62, synthetic fibers, such as electroconductive nylon, an acryl, and polyester, are used, for example, and the thing of the thickness of 1 denier-10 denier is used, for example.

  The rotating brush 8 is driven to rotate in a required direction C at a required speed by transmitting rotational power from a rotational drive device (not shown). The rotating brush 8 in the first embodiment is set so that the rotation direction C thereof is the same as the rotational movement direction B of the belt 31 at the contact position with the intermediate transfer belt 31, and the rotation speed thereof is the intermediate transfer. For example, the speed is set to 1 to 3 times the rotation (movement) speed of the belt 31.

  Further, in the rotating brush 8, the voltage of the charging polarity (negative polarity in the first embodiment) of the developer G remaining on the intermediate transfer belt 31 is applied to one end portion of the core member 81 from a power source (not shown) via a power feeding element. Have been supplied. Further, a back support roll for supporting the position of the outer surface portion of the intermediate transfer belt 31 in contact with the bristle material 82 of the rotary brush 8 at the position of the inner peripheral surface of the intermediate transfer belt 31 facing the rotary brush 8. 84 is provided.

  Further, the rotary brush 8 is provided with a scraping member 85.

  The scraping member 85 is provided at a position where the scraping member 85 comes into contact with the hair material 82 after contacting the outer surface of the intermediate transfer belt 31 of the rotary brush 8, and the hair material 82 is temporarily elastically deformed and then restored. This is a member for scraping off the developer adhering to the hair material 82. As shown in FIG. 4 and the like, the scraping member 85 is formed of an elongated metal rod having a circular cross section. As such a scraping member (bar) 85, for example, a member having a required thickness (diameter of a cross section) and a length extending in parallel with the axial direction of the rotating brush 8 is used. .

  In addition, the scraping bar 85 is supported by the support member 86, for example, a state in which about 1/3 of the circular portion of the cross section enters the inner space of the bristle material 82 (group) where the rotary brush 8 stands. Placed in. Further, the position (installation position) of the scraping bar 85 in contact with the bristle material 82 of the rotating brush 8 is a position where the developer adhering to the bristle material 82 after contacting the intermediate transfer belt 31 can be efficiently scraped off. Set to

  The support member 86 is provided with a main body portion 87 having a length corresponding to the length of the scraping rod 85 that is a scraping member, and a state protruding from the main body portion 87 toward the rotary brush 8 at an interval. A plurality of mounting support portions 88 are included. The main body portion 87 is provided with a guide wall surface 87 a that guides the developer that has been scraped off to drop toward the recovery conveyance member 9.

  Further, the support member 87 has a structure in which a space S1 penetrating in a direction substantially along the gravity direction G is formed between adjacent mounting support portions 89 as shown in FIG. This space S <b> 1 is used as a space for dropping the developer scraped off by the scraping rod 86 toward the collection conveyance member 9.

  As shown in FIG. 4, the collection conveyance member 9 is provided in a conveyance groove 53 formed in a position below the scraping rod 86 in the gravity direction G in the apparatus main body 50, and the rotating brush 6 is rotated by the scraping rod 86. The developer scraped off from the hair material 62 is collected and transported to a developer collecting container (not shown), for example. As the collection conveyance member 9, as shown in FIG. 5 or the like, one having a structure in which a spiral conveyance blade portion 92 is formed around the rotation shaft 91 (for example, a screw auger) is used.

  The collecting and conveying member 9 is arranged so that the rotating shaft 91 is substantially parallel to the rotating shaft 81 of the rotating brush 8, and both ends of the rotating shaft 91 are formed in the conveying groove portion 53 of the apparatus main body 50. It is mounted in a state of being supported so as to be rotatable inside. Further, the collection conveying member 9 is distributed with rotational power from a rotary drive device (not shown) used for the rotary brush 8 and transmitted to the end of the rotary shaft 91, thereby rotating in a required direction D at a required speed. It comes to drive. 4 is a leakage preventing member (seal member) for preventing the developer from leaking from the inside of the apparatus main body 50, and one end portion thereof is in contact with the outer surface of the intermediate transfer belt 31. It is being fixed to the apparatus main body 50 side so that it may become.

  Hereinafter, the basic operation of the belt cleaning device 5 will be described.

  First, in the belt cleaning device 5, the rotating brush 8, the elastic cleaning plate 6, and the metal cleaning plate 7 are arranged in this order on the outer surface of the intermediate transfer belt 31 that rotates and moves in the direction of arrow B after the completion of the secondary transfer. Contact with.

  As a result, unwanted materials such as developer remaining on the outer surface of the intermediate transfer belt 31 after the secondary transfer are first physically impacted by the bristle material 82 of the rotating brush 8 that rotates in the direction of arrow C. Then, a part of the attached developer is scraped off. Further, the bristle material 82 of the rotating brush 8 is supplied with a voltage having the same polarity as the charging polarity of the developer adhering to the intermediate transfer belt 31 (negative polarity in the first embodiment). The developer that adheres receives an electrostatic repulsive force, and easily drops off from the intermediate transfer belt 31. In addition, the developer that has been scraped off does not adhere electrostatically to the bristle material 82 of the rotating brush 8 and does not accumulate.

  Subsequently, the developer 15b and the like on the outer surface of the intermediate transfer belt 31 come into contact with each other at a position downstream of the rotary brush 8 in the rotation direction B of the intermediate transfer belt 31 as shown in FIG. Most of the elastic plate 61 is scraped off by the tip 61 a of the elastic plate 61 and falls toward the inside of the apparatus main body 50. Finally, deposits such as developer remaining on the outer surface of the intermediate transfer belt 31 without being scraped off by the elastic cleaning plate 6 are finally scraped off by the metal cleaning plate 7, and most of them are scraped off. 50 drops to the developer collecting section 55 and is collected.

  Further, as described above, the developer scraped off by the rotary brush 8 and the elastic cleaning plate 6 is captured from the beginning by the bristle material 82 of the rotary brush 8 or dropped by the scraping of the elastic cleaning plate 6 and supplemented. And is conveyed by the rotation of the rotating brush 8. The developer that is conveyed while being supplemented by the bristle material 82 of the rotating brush 8 is temporarily elastically deformed by contact with the scraper bar 85 when passing through the scraper bar 85. Since it behaves like restoring, it is scraped off from the bristle material 82.

  At this time, a part of the developer passes through the gap between the bristle material 82 between the scraping bar 85 and the rotation shaft 81 of the rotary brush 8 and is detached from the bristle material 82, and is more gravitational than the scraping bar 85. It is blown or dropped toward the collection conveyance member 9 arranged on the lower side in the direction G. Further, the other developer is ejected from the contact start position where the scraping bar 85 starts to contact the bristle material 82 of the rotating brush 8 to the upper space, but thereafter, the other side of the scraping bar 85 is opposite to the rotating brush 8. Is moved through the space S1 formed between the scraping bar 85 and the main body 86 of the support member 86, and finally moves toward the collection conveyance member 9.

  Next, in the belt cleaning device 5, the cleaning target is the intermediate transfer belt 31 in which PTFE resin particles are dispersed. The effectiveness of the cleaning operation for the intermediate transfer belt 31 will be described.

  First, as shown in FIG. 7A, the intermediate transfer belt 31 in which resin particles of PTFE are dispersed immediately after the production or before being used in the image forming apparatus 1 is used. A part of the PTFE resin particles 4b and 4c is exposed on the surface 31a.

  Therefore, when the intermediate transfer belt 31 passes through the belt cleaning device 5 in the initial stage after the start of use, the PTFE exposed by the elastic cleaning plate 6 that is in strong contact with the outer surface 31a of the belt. A part of the resin particles 4c is collected and removed from the outer surface 31a. On the other hand, the other part of the PTFE resin particles 4 is stretched into a thin film by the elastic cleaning plate 6 due to the property that the fluororesin tends to be stretched, so that the coating 4m is formed in places on the outer surface 31a of the belt. Become.

  At this time, in the belt cleaning device 5, as shown in FIG. 6, in front of the front end portion 61 a of the elastic plate 61 in the elastic cleaning plate 6 (a wedge-shaped space surrounded by the outer surface 31 a of the intermediate transfer belt 31), Part of the developer 15b mainly stays. Further, in front of the tip 71a of the metal plate 71 in the metal cleaning plate 7 (same as above), PTFE resin particles 4c having a particle diameter smaller than that of the developer 15, external additives 16 of the developer, etc. are attached to the elastic cleaning plate 6. It slips through and partly stays.

  Subsequently, as the intermediate transfer belt 31 is repeatedly used thereafter, the PTFE resin particles 4c may be removed by the scraping action of the elastic cleaning plate 6. In this case, as shown in FIG. As shown, a drop-out recess 31b having a diameter of about 0.1 to several μm is formed in the portion where the PTFE resin particles 4c existed.

  The portion of the intermediate transfer belt 31 where the PTFE resin particle 4c drop-out recess 31b is formed is in a state in which the adhesive force with the developer is relatively increased as compared with other portions due to the absence of the PTFE resin. . For this reason, if the metal cleaning plate 7 is not provided in the belt cleaning device 5, when the elastic cleaning plate 6 of the drum cleaning device 5 is repeatedly passed through the dropping recess 31 b of the intermediate transfer belt. The developer 15b (FIG. 6) staying in front of the tip 61a of the elastic plate 61 in the elastic cleaning plate 6 is pressed, and the developer 15b is fixed and gradually accumulates as shown in FIG. As a result, the developer aggregate 15c is present.

  In particular, the developer 15b staying in front of the front end portion 61a of the elastic plate 61 in the elastic cleaning plate 6 remains on the outer surface 31a of the intermediate transfer belt 31 without being transferred to the recording paper 19 at the secondary transfer portion. Since the external additive is released and easily adheres to the outer surface 31a of the belt, it is easy to fix to the part of the falling recess 31b and grows as an aggregate 15c. It has become easier.

  When the developer aggregate 15 c is present on a part of the outer surface 31 a of the intermediate transfer belt 31, a part of the tip 61 a of the elastic plate 61 of the elastic cleaning plate 6 in the belt cleaning device 5 is the aggregate. It will be lifted by 15c. As a result, a streak-like poorly cleaned portion occurs on a part of the outer surface 31a of the intermediate transfer belt 31, and a streak-like image quality defect (density unevenness or missing) due to the poorly cleaned portion occurs. It becomes like this.

  Further, the intermediate transfer belt 31 is captured by the recording sheet 19 that contacts the secondary transfer portion in addition to the PTFE resin film 4m being scraped off by the scraping action of the elastic cleaning plate 6. As a result, the thickness of the coating 4m gradually decreases as shown in FIG. For this reason, the effect of imparting releasability to the developer due to the presence of the PTFE resin particles 4 on the outer surface 31a of the intermediate transfer belt 31 gradually decreases.

  On the other hand, in the belt cleaning device 5 according to the first embodiment, the metal cleaning plate 7 is disposed downstream of the elastic cleaning plate 6 in the rotation direction B of the intermediate transfer belt 31.

  For this reason, prior to the developer 15b staying in front of the front end portion 61a of the elastic cleaning plate 6 being filled in the dropping recess 31b of the PTFE resin particles 4c in the intermediate transfer belt 31, FIG. As shown in a), the PTFE resin particles 4c staying in front of the tip 71a of the metal plate 71 in the metal cleaning plate 7 and the external additive 16 of the developer are easily supplemented. As a result, the developer 15b staying in front of the front end portion 61a of the elastic cleaning plate 6 does not adhere to the dropping recess 31b of the PTFE resin particles 4c.

  In particular, the metal cleaning plate 7 has a higher hardness than the elastic cleaning plate 6 (hard physical properties), and the portion that contacts the outer surface 31a of the intermediate transfer belt 31 because the tip 71a is not elastically deformed. The width (the length in the belt rotation direction B) of the elastic cleaning plate 6 is narrower than the tip 61a of the elastic cleaning plate 6 which is elastically deformed. The force that presses against the elastic cleaning plate 6 is much larger than that of the tip 61a of the elastic cleaning plate 6. As a result, the PTFE resin particles 4c and the developer external additive 16 staying in front of the front end portion 71a of the metal cleaning plate 7 are preferentially placed in the dropping recess 31b of the PTFE resin particles 4c in the intermediate transfer belt 31. It comes to be pressed.

  Even when the developer 15b staying in front of the front end portion 61a of the elastic cleaning plate 6 is fixed to the dropping recess 31b of the PTFE resin particles 4c in the intermediate transfer belt 31, the front end portion 71a of the metal cleaning plate 7 is fixed. Is not elastically deformed and contacts the outer surface 31a of the belt, so that the developer 15b starts to aggregate in the drop-off recess 31b before the developer 15b adheres to the drop-off recess 31b and grows into a large developer aggregate 15c. Is scraped off at the tip 71a of the metal cleaning plate 7.

  In addition, the PTFE resin film 4m formed on the outer surface 31a (flat portion) other than the dropping recess 31b of the PTFE resin particles 4c in the intermediate transfer belt 31 is gradually scraped and recorded by the elastic cleaning plate 6 as described above. The thickness gradually decreases due to the action of capturing the contact with the sheet 19 or the like. However, similar to the principle that the PTFE resin particles 4c and the external additive 16 of the developer are supplemented into the drop-off depression 31b by repeatedly passing through the metal cleaning plate 7, the coating 4m is also shown in FIG. As shown in (b), the PTFE resin particles 4c staying in front of the tip 71a of the metal cleaning plate 7 and the external additive 16 of the developer are gradually supplemented.

  As described above, in the intermediate transfer belt 31 in which the PTFE resin particles cleaned by the belt cleaning device 5 are dispersed, the developer aggregate 15c is prevented from growing in the dropping recess 31b of the PTFE resin particles 4c. Therefore, the occurrence of the streaky cleaning failure due to the presence of the developer aggregate 15c is prevented, and the cleaning performance is prevented from deteriorating. Further, in the image forming apparatus 1 equipped with the belt cleaning device 5, the occurrence of streak-like image quality defects due to poor cleaning in the intermediate transfer belt 31 is also suppressed. No good image formation is possible.

  Further, in the intermediate transfer belt 31 in which the PTFE resin particles to be cleaned by the belt cleaning device 5 are dispersed, the PTFE resin particles 4c and the external additive 16 of the developer are supplemented in the dropping recesses 31b of the PTFE resin particles 4c. Moreover, since the PTFE resin particles 4c and the external additive 16 of the developer are also supplemented to the PTFE resin film 4m formed on the belt outer surface 31a other than the drop-off recess 31b, the developer on the outer surface 31a can be Releasability is maintained. As a result, in the image forming apparatus 1 equipped with the belt cleaning device 5, the toner image (developer image) held on the intermediate transfer belt 31 in the secondary transfer unit is efficiently secondary-transferred to the recording paper 19. In addition, even if the developer that is not transferred to the outer surface 31a of the intermediate transfer belt 31 remains, the effect of scraping off the developer by the elastic cleaning plate 6 of the belt cleaning device 5 is exhibited well and is cleaned well. Become so.

  FIG. 11 shows the results of an evaluation test performed on the belt cleaning device 5.

  In the test, belt cleaning devices 5 according to the first embodiment, which are set to the following conditions and the conditions shown in FIG. 11, are prepared, and each belt cleaning device 5 is the image forming device 1 according to the first embodiment. The image forming apparatus was used to check the image results and the surface state of the intermediate transfer belt 31 after a test image was formed on 50,000 sheets of recording paper 19 (A4 size plain paper, laterally fed). At this time, the test image was formed in an environment of a temperature of 22 ° C. and a humidity of 55% RH.

<Belt cleaning device 5>
As the metal cleaning plate 7, a rectangular plate made of stainless steel (SUS304) with a thickness of 0.1 mm and a width of 341 mm is used, and the plate is attached so that the contact angle θ2 is 23 degrees, and the amount of biting β at that time, The free length Lf7 and the contact load F7 were set to be the values shown in FIG. The stainless steel has a shape excellent in its perpendicularity and linearity by etching the tip 71a (corner thereof) in contact with the belt.
As the elastic cleaning plate 6, a rectangular plate made of polyurethane rubber having a thickness of 2 mm and a width of 341 mm is used, and the plate is attached so that the contact angle θ1 is 24 degrees, and the biting amount α at that time is 1.0 mm. The free length Lf6 was set to 8 mm, and the contact load F6 was set to 29.4 N / m.

  Here, the contact load is set by a constant displacement method in which the amount of biting (α, β) is fixed to a target value, and then a strain gauge measuring instrument (manufactured by National Instruments: NI9237, NIcDAQ-9174) is used. It was measured. For reference, a belt cleaning device (comparative example) in which the metal cleaning plate 7 is not attached was also prepared and used. In addition, according to the present inventors, even when a required contact load is applied by a constant load method in which the cleaning plate is pressed by an external spring or the like, the result of the evaluation test is the same as the result shown in FIG. Has been confirmed.

<Image forming apparatus 1>
The intermediate transfer belt 31 is obtained by applying a polyimide varnish to which a PTFE resin having an average particle size of 3.5 μm is added to a belt base material 310 made of a polyimide resin so that the addition amount is 10% and then drying. used.
As the developer 15, a two-component developer containing a nonmagnetic toner made of a polyester resin having an average particle diameter of 3.8 μm and a magnetic carrier having an average particle diameter of 25 μm was used. To the nonmagnetic toner, an external additive composed of silica, cerium oxide having an average particle diameter of 0.01 to 1 μm, and fluorine-containing resin fine particles (PTFE) was adhered as a cleaning aid.

About the said image result, the generation | occurrence | production condition of the streak-like image defect resulting from the cleaning defect in the belt cleaning apparatus 5 was investigated to the obtained image, and the result was evaluated on the following references | standards. Further, regarding the surface state of the intermediate transfer belt, the surface of the intermediate transfer belt after the formation of the test image was observed to examine the occurrence of streak belt scratches, and the results were evaluated according to the following criteria.
XX: Remarkably generated.
X: It occurred.
Δ: Slight occurrence occurred, but at a level where there was no practical problem.
○: Not generated.

  As is apparent from the results of FIG. 11, when the contact load F7 of the metal cleaning plate 7 is set in the range of 4.9 to 49.0 N / m, good results that are not regarded as a problem in practice can be obtained. Furthermore, when the contact load F7 is set in the range of 14, 7 to 39.2 N / m, a better result can be obtained. When the contact load F7 of the metal cleaning plate 7 is set to a value smaller than 4.9 N / m, a cleaning failure occurs, and a streak-like image defect due to the cleaning failure occurs. On the other hand, when the contact load F7 is set to a value larger than 49.0 N / m, a streak-like scratch is generated on the outer surface of the intermediate transfer belt 31, and a streak-like image defect is also caused. End up.

  According to the present inventors, when the belt cleaning device 5 in which the contact angle θ2 of the metal cleaning plate 7 is set to a plurality of angles arbitrarily selected from the range of 10 to 40 degrees is prepared and an evaluation test is performed. However, good results can be obtained as a result of the evaluation test using the contact load F7 of the metal cleaning plate 7 as described above. It has been confirmed that it is the same as the range of 9 to 49.0 N / m or less. In addition, according to the present inventors, even when a required contact load is applied by a constant load method in which the cleaning plate is pressed by an external spring or the like, the result of the evaluation test is the same as the result shown in FIG. Has been confirmed.

[Other embodiments]
In Embodiment 1, although the case where the rotating brush 8 was installed was illustrated as the belt cleaning apparatus 5, the cleaning apparatus which does not install the rotating brush 8 may be sufficient. In addition, the intermediate transfer belt 31 in which PTFE resin particles are dispersed is exemplified as a cleaning target of the belt cleaning device 5. However, as the cleaning target, for example, a PTFE resin that holds and transports a recording sheet in a transfer unit. It may be a paper conveyance transfer belt in which particles are dispersed.

  In addition, the image forming apparatus 1 may be an image forming apparatus equipped with a transfer belt formed by dispersing PTFE resin particles to which the cleaning device of the present invention is applied. It doesn't matter. For example, the secondary transfer device 35 may be of a roll type.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 4 ... PTFE resin particle 4c ... PTFE resin particle 5 exposed on the belt surface or removed from the belt surface ... Belt cleaning device (an example of cleaning device)
6 ... Elastic cleaning plate 7 ... Metal cleaning plate (an example of a metal plate)
DESCRIPTION OF SYMBOLS 15 ... Developer 16 ... External additive 20 ... Image forming apparatus 21 ... Photosensitive drum (an example of an image carrier)
31 ... Intermediate transfer belt (an example of a transfer belt)
31a ... outer surface 35 ... secondary transfer device (part of transfer section)
61a ... tip 71a elastically deformed ... tip B not elastically deformed ... direction of rotation

Claims (4)

A developer image composed of a developer with an external additive is held on the outer surface and rotated so as to be conveyed to a transfer portion to be transferred to a recording material, and resin particles made of polytetrafluoroethylene are dispersed. An elastic cleaning plate that removes the remaining developer by contacting the elastically deformed tip to the outer surface of the transfer belt after passing through the transfer portion;
A cleaning apparatus comprising: a metal cleaning plate that contacts a tip portion that does not elastically deform on an outer surface at a position downstream of the elastic cleaning plate in the rotation direction of the transfer belt.   The cleaning device according to claim 1, wherein the metal cleaning plate is installed so that a contact load with respect to an outer surface of the transfer belt is in a range of 4.9 N / m to 49.0 N / m. An image forming apparatus for forming a developer image developed with a developer coated with an external additive on an image carrier;
The developer image formed on the image holding body of the image forming apparatus is rotated so as to be conveyed to a secondary transfer portion that is held on the outer surface and transferred to a recording material, and resin particles made of polytetrafluoroethylene are dispersed. An intermediate transfer belt,
An elastic cleaning plate that removes the remaining developer by contacting a tip portion that is elastically deformed to the outer peripheral surface after passing through the secondary transfer portion of the intermediate transfer belt, and the elastic cleaning plate in the rotational direction of the transfer belt An image forming apparatus comprising: a cleaning device provided with a metal cleaning plate that contacts a distal end portion that does not elastically deform with an outer surface at a position on the downstream side.   The image forming apparatus according to claim 3, wherein the metal cleaning plate in the cleaning device is installed so that a contact weight with respect to an outer surface of the transfer belt is in a range of 4.9 N / m to 49.0 N / m. apparatus.

Images