JP2011070180A - Image forming apparatus and method for processing transfer surface of intermediate transfer belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that includes: a cleaning member for recovering residual toner adhering to the surface of an intermediate transfer belt; and an auxiliary cleaning member for reducing the adhering force of the residual toner in contact with the same, the auxiliary cleaning member having inorganic powder in the initial state. <P>SOLUTION: A color copying machine 1 includes: the main cleaning member 180 disposed on the transfer surface 7A side of the intermediate transfer belt 7 and downstream of a secondary transfer roller 8, and used for removing residual toner adhering to the transfer surface 7A; and the auxiliary cleaning member 190 disposed on the transfer surface 7A side of the intermediate transfer belt 7 and upstream of the cleaning member 180 in the rotating direction of the intermediate transfer belt 7, used to reduce adhering force of the residual toner in contact with the residual toner adhering to the transfer surface 7A, and having one or two types of inorganic powder in an initial state. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a transfer surface processing method for an intermediate transfer belt.

  Conventionally, there is a type that uses toner in an image forming apparatus such as a copying machine. In an image forming apparatus using toner, there is a type in which a toner image formed on an image carrier is primarily transferred to an intermediate transfer belt, and the toner image primarily transferred to the intermediate transfer belt is secondarily transferred to a predetermined sheet. Exists. In this type of image forming apparatus, residual toner that remains without being transferred onto the sheet may adhere to the surface of the intermediate transfer belt, and therefore a cleaning member (cleaning member) that normally removes the residual toner that has adhered thereto. Is placed. Further, an image forming apparatus having a cleaning auxiliary member (auxiliary cleaning member) that contacts the residual toner and weakens the adhesion force on the upstream side of the cleaning member in order to remove the residual toner that is compressed and attached to the intermediate transfer belt. It has been proposed (see, for example, Patent Document 1).

On the other hand, in an image forming apparatus using toner, an additive (for example, an inorganic powder such as an abrasive or a fluidizing agent) contained in the toner that cannot be removed by the cleaning member adheres to the intermediate transfer belt ( Whitening).
Here, the additive may adhere to the surface of the intermediate transfer belt in a state (mode) in which there are streaky irregularities (formed so that a plurality of linear streaks are arranged in the width direction). If the additive adheres to the intermediate transfer belt with streak-like unevenness (mode), the transfer efficiency differs between the portion where the additive is present (the streak portion) and the portion where the additive is not present. In some cases, streaky density unevenness or omission occurs in the transferred toner image.

  In contrast, the toner image is primarily transferred to an intermediate transfer belt (for example, the entire surface) at a predetermined timing, and the primary transferred toner image is collected without being secondarily transferred. An image forming apparatus that performs a cleaning process for collecting the additive adhering to the toner together with the toner has been proposed (see, for example, Patent Document 2).

JP 2008-292700 A JP 2007-232842

Here, in the image forming apparatus of Patent Document 1, there is a problem that the cleaning member and the cleaning auxiliary member cannot completely remove the additive adhering to the surface of the intermediate transfer belt.
Further, the image forming apparatus of Patent Document 2 has a problem that a predetermined amount of toner needs to be wasted in order to perform the cleaning process. In particular, in order to perform the cleaning process on the entire surface of the intermediate transfer belt, there is a problem that a large amount of toner needs to be wasted.
Further, in both of the image forming apparatus of Patent Document 1 and the image forming apparatus of Patent Document 2, even when the adhering additive is removed by the cleaning process, the additive adheres again after a predetermined period of time, and the streak-like There may be unevenness.

Here, as a method of suppressing the occurrence of streaky density unevenness and omission in the toner image transferred onto the paper, there are a method of removing the adhering additive and a method of adhering the additive to the entire surface of the intermediate transfer belt in advance. is there. By preliminarily attaching the additive to the entire surface of the intermediate transfer belt, the transfer efficiency becomes uniform, and density unevenness and the like can be suppressed from occurring in the toner image transferred onto the paper.
For example, before shipping from a factory or the like, a toner image that has been transferred onto a sheet of paper by applying the additive to the surface of the intermediate transfer belt manually or by a dedicated device so that the additive adheres to the entire surface of the intermediate transfer belt. It is possible to suppress density unevenness and the like from occurring.
However, even in this case, there is a problem that there is a burden on work and a burden on manufacturing cost.

The present invention is a cleaning member that collects residual toner attached to the surface of an intermediate transfer belt, and a cleaning auxiliary member that makes contact with the residual toner and weakens the adhesive force of the residual toner, and has an inorganic powder in an initial state. An object of the present invention is to provide an image forming apparatus including an auxiliary member.
Another object of the present invention is to provide a transfer surface processing method for an intermediate transfer belt in the image forming apparatus.

  The present invention provides one or more image carriers having an electrostatic latent image formed on the surface, and one or more developments for developing a toner image on the electrostatic latent images formed on the one or more image carriers. An intermediate transfer belt having a transfer surface on which a toner image formed by the one or more image carriers is primarily transferred, and an intermediate transfer belt that is rotatable in a ring direction. The toner image that has been primarily transferred with the intermediate transfer belt and the sheet-shaped transfer material disposed on the transfer surface side interposed between the one or the plurality of image carriers in the rotation direction of the belt. Is disposed on the transfer surface side of the intermediate transfer belt and on the downstream side of the secondary transfer roller in the rotational direction. Remove remaining toner A cleaning member is disposed on the transfer surface side of the intermediate transfer belt and upstream of the cleaning member in the rotational direction, and contacts the residual toner adhering to the transfer surface to reduce the adhesion force of the residual toner. The present invention relates to an image forming apparatus comprising: a cleaning auxiliary member to be cleaned, and a cleaning auxiliary member having one or more inorganic powders in an initial state.

  Further, it is preferable that a plurality of concave portions and / or convex portions are formed on the transfer surface of the intermediate transfer belt.

  Further, it is preferable that the cleaning auxiliary member is capable of forming the inorganic powder layer by rotating the intermediate transfer belt in an initial state to transfer the inorganic powder to the surface of the transfer surface.

  The intermediate transfer belt is a layer of inorganic powder formed on the transfer surface, and is formed of the inorganic powder transferred from the cleaning auxiliary member by rotating the intermediate transfer belt in an initial state. It is preferable to have an inorganic powder layer.

  Preferably, the cleaning member includes a fur brush having a plurality of brush bristles that are in sliding contact with the intermediate transfer belt, and each of the plurality of brush bristles is formed by integrating a plurality of fibers.

  Further, each of the plurality of brush bristles is in sliding contact with the intermediate transfer belt having the inorganic powder layer in a rotating state at the tip, and the tip is integrated with a plurality of fibers constituting the tip. Is released, the rigidity is lower than a portion different from the tip portion, and the contact area to the intermediate transfer belt having the inorganic powder layer is larger than the contact area in the initial state. Is preferred.

  The plurality of fibers constituting the bristles are preferably made of a material having a hardness higher than that of the material constituting the surface of the intermediate transfer belt and lower than that of the inorganic powder.

  The inorganic powder is preferably a fluidizing agent and / or an abrasive contained in the toner.

  The present invention also provides a surface treatment method for an intermediate transfer belt in which an inorganic powder layer is formed on the transfer surface of the intermediate transfer belt in the image forming apparatus, wherein the intermediate transfer belt is attached to the intermediate transfer belt for a predetermined time in an initial state. The present invention relates to a transfer surface processing method for an intermediate transfer belt, which includes a step of forming a layer of the inorganic powder by rotating the inorganic powder of the cleaning auxiliary member to the surface of the transfer surface by rotating.

According to the present invention, a cleaning member that collects residual toner attached to the surface of the intermediate transfer belt, and a cleaning auxiliary member that makes contact with the residual toner and weakens the adhesive force of the residual toner, the inorganic powder in the initial state. An image forming apparatus including the cleaning assisting member can be provided.
Further, the present invention can provide a transfer surface processing method for an intermediate transfer belt in the image forming apparatus.

2 is a diagram for explaining the arrangement of each component of the color copier 1. FIG. FIG. 3 is a diagram for explaining a configuration of a transfer unit in the color copier 1. 4 is an enlarged cross-sectional view of a main part for explaining a specific structure of the cleaning device 100. FIG. 4 is a diagram illustrating a state in which an abrasive k adheres to form a layer on a transfer surface 7A of an intermediate transfer belt 7. FIG. FIG. 4 is a diagram for explaining a state where a fluidizing agent r is further adhered to the transfer surface 7A of the intermediate transfer belt 7 to which an abrasive k is deposited to form a layer. FIG. 7 is a diagram for explaining good releasability of toner t with respect to a transfer surface 7A having a fluidizing agent r attached to the surface. It is a table | surface which shows the relationship between the number of printed sheets of 1st Example and a 1st comparative example, whitening, and image evaluation.

Hereinafter, embodiments of an image forming apparatus of the present invention will be described with reference to the drawings.
With reference to FIG. 1, the overall structure of a color copier 1 as an image forming apparatus in the present embodiment will be described. FIG. 1 is a diagram for explaining the arrangement of each component of the color copier 1.

As shown in FIG. 1, a color copier 1 as an image forming apparatus includes an image reading device 300 disposed on the upper side in the vertical direction Z of the color copier 1 and a lower side of the color copier 1 in the vertical direction Z. And an apparatus main body M that forms a toner image on a sheet T as a sheet-like transfer material based on image information read by the image reading apparatus 300.
In the description of the color copying machine 1, the sub-scanning direction X is also referred to as the “left-right direction” of the color copying machine 1, and the main scanning direction Y (direction perpendicular to the paper surface of FIG. " The vertical direction Z of the color copier 1 is orthogonal to the sub-scanning direction X and the main scanning direction Y.

First, the image reading apparatus 300 will be described.
As shown in FIG. 1, the image reading apparatus 300 includes a lid member 70 and a reading unit 301 that reads an image of a document G.
The lid member 70 is connected to the reading unit 301 so as to be opened and closed by a connecting unit (not shown). The lid member 70 has a function of protecting a reading surface 302A described later.

  The reading unit 301 includes a housing 306 and a reading surface 302 </ b> A disposed on the upper side of the housing 306. The reading unit 301 includes an illumination unit 340 including a light source, a plurality of mirrors 321, 322, and 323, and a first frame 311 and a second frame that move in the sub-scanning direction X in an internal space 304 of the housing 306. A body 312, an imaging lens 357, a CCD 358 serving as a reading unit, and a CCD substrate 361 that performs predetermined processing on image information read by the CCD 358 and outputs the image information to the apparatus main body M side. Prepare. The illumination unit 340 and the first mirror 321 are accommodated in the first frame 311. The second mirror 322 and the third mirror 323 are accommodated in the second frame 312.

  The reading surface 302A extends in a direction perpendicular to the sub-scanning direction X and the main scanning direction Y, and extends over most of the sub-scanning direction X in the reading unit 301. The document G is placed on the reading surface 302A. Each of the first frame 311 and the second frame 312 moves in the sub-scanning direction X while keeping the length of an optical path H (optical path length) to be described later constant. Thereby, the image of the original G placed on the reading surface 302A is read.

  In the internal space 304 of the housing 306, the plurality of mirrors 321, 322, and 323 form an optical path H for allowing light from the original G to enter the imaging lens 357. In addition, the first frame 311 moves at a constant speed A in the sub-scanning direction X, and the second frame 312 moves at a constant speed A / 2 in the sub-scanning direction X. The length of H is kept constant. Details of the reading unit 301 will be described later.

Next, the apparatus main body M will be described.
The apparatus main body M is configured to form a predetermined toner image on the paper T based on predetermined image information, and to feed the paper T to the image forming unit and to discharge the paper T on which the toner image is formed. And a paper supply / discharge unit.

  As shown in FIG. 1, the image forming unit includes photosensitive drums 2a, 2b, 2c, and 2d as image carriers (photosensitive members), charging units 10a, 10b, 10c, and 10d, and a laser scanner as an exposure unit. Units 4a, 4b, 4c, 4d, developing devices 16a, 16b, 16c, 16d, toner cartridges 5a, 5b, 5c, 5d, toner supply units 6a, 6b, 6c, 6d, and drum cleaning units 11a, 11b 11c, 11d, static eliminators 12a, 12b, 12c, 12d, intermediate transfer belt 7, primary transfer rollers 37a, 37b, 37c, 37d, secondary transfer roller 8, counter roller 18, and cleaning device 100 and a fixing unit 9.

  As shown in FIG. 1, the paper feed / discharge unit includes a paper feed cassette 52, a manual paper feed unit 64, a conveyance path L for paper T, a registration roller pair 80, a first paper discharge unit 50 a, and a second paper feed unit. A paper discharge unit 50b. As will be described later, the transport path L includes a first transport path L1, a second transport path L2, a third transport path L3, a manual transport path La, a return transport path Lb, and a post-processing transport path Lc. Is a collection of

Hereinafter, each configuration of the image forming unit and the paper supply / discharge unit will be described in detail.
First, the image forming unit will be described.
In the image forming unit, charging by the charging units 10a, 10b, 10c, and 10d in order from the upstream side to the downstream side with respect to the respective surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, and the laser scanner units 4a, 4b, 4c, 4d exposure, development devices 16a, 16b, 16c, 16d development, intermediate transfer belt 7 and primary transfer rollers 37a, 37b, 37c, 37d primary transfer, static eliminators 12a, 12b, 12c, 12d And cleaning by the drum cleaning units 11a, 11b, 11c, and 11d.
In the image forming unit, secondary transfer by the intermediate transfer belt 7, the secondary transfer roller 8 and the counter roller 18, and fixing by the fixing unit 9 are performed.

  Each of the photosensitive drums 2a, 2b, 2c, and 2d is formed of a cylindrical member and functions as a photosensitive member or an image carrier. Each of the photosensitive drums 2 a, 2 b, 2 c, and 2 d is disposed so as to be rotatable in the direction of an arrow about an axis that extends in a direction orthogonal to the traveling direction of the intermediate transfer belt 7. An electrostatic latent image is formed on the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d.

  Each of the charging units 10a, 10b, 10c, and 10d is disposed to face the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the charging units 10a, 10b, 10c, and 10d uniformly charges the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d negatively (minus polarity) or positively (plus polarity).

  The laser scanner units 4a, 4b, 4c, and 4d function as exposure units, and are spaced apart from the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the laser scanner units 4a, 4b, 4c, and 4d includes a laser light source (not shown), a polygon mirror, a polygon mirror driving motor, and the like.

  Each of the laser scanner units 4a, 4b, 4c, and 4d scans and exposes the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d based on image information related to the image read by the reading unit 301. Scanning exposure is performed by each of the laser scanner units 4a, 4b, 4c, and 4d, so that charges charged on the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d are removed. Thereby, electrostatic latent images are formed on the respective surfaces of the photosensitive drums 2a, 2b, 2c, and 2d.

  The developing devices 16a, 16b, 16c, and 16d are provided corresponding to the photosensitive drums 2a, 2b, 2c, and 2d, respectively, and are disposed to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the developing devices 16a, 16b, 16c, and 16d develops a color toner image by attaching toner of each color to the electrostatic latent images formed on the photosensitive drums 2a, 2b, 2c, and 2d (photosensitive drums). A toner image is formed on the surface). Each of the developing devices 16a, 16b, 16c, and 16d corresponds to four toner colors of yellow, cyan, magenta, and black. Each of the developing devices 16a, 16b, 16c, and 16d includes a developing roller that can be disposed opposite to the surface of the photosensitive drums 2a, 2b, 2c, and 2d, a stirring roller for stirring the toner, and the like.

  Each of the toner cartridges 5a, 5b, 5c, and 5d is provided corresponding to each of the developing devices 16a, 16b, 16c, and 16d, and each color toner supplied to each of the developing devices 16a, 16b, 16c, and 16d. To accommodate. Each of the toner cartridges 5a, 5b, 5c, and 5d accommodates yellow toner, cyan toner, magenta toner, and black toner.

  The toner supply units 6a, 6b, 6c, and 6d are provided corresponding to the toner cartridges 5a, 5b, 5c, and 5d and the developing devices 16a, 16b, 16c, and 16d, respectively. The toners of the respective colors accommodated in 5d are supplied to the developing devices 16a, 16b, 16c, and 16d, respectively.

  The toner images of the respective colors developed on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially transferred to the intermediate transfer belt 7. The intermediate transfer belt 7 is stretched around a driven roller 35, a counter roller 18 including a driving roller, a tension roller 36, and the like. Since the tension roller 36 biases the intermediate transfer belt 7 from the inside to the outside, a predetermined tension is applied to the intermediate transfer belt 7.

  Primary transfer rollers 37a, 37b, 37c, and 37d are arranged to face each other on the side opposite to the photosensitive drums 2a, 2b, 2c, and 2d with the intermediate transfer belt 7 interposed therebetween. The intermediate transfer belt 7 is formed, for example, in an endless shape having a three-layer structure in which an elastic material is pasted on a resin body and fluorine particles are applied to the outer surface of the elastic material. As the resin body, polyimide resin, fluororesin, PVDF (PolyVinylline DiFluoride), or the like is used. As the elastic material, an elastomer such as chlorobrene rubber, EPDM (Ethylene Propylene Methylene Linkage) rubber, polyurethane rubber or the like is used. The coating layer is formed using a coating agent such as a fluororesin, a silicon resin, an acrylic resin, or a urethane resin.

  In this embodiment, as the resin body of the intermediate transfer belt 7, for example, PVDF (PolyVinylline DiFluoride) having a thickness of 80 to 150 μm is used. As the elastic material of the intermediate transfer belt 7, for example, chlorobrene rubber having a thickness of 300 to 600 μm is used. The coating layer on the outer surface of the intermediate transfer belt 7 is composed of, for example, fluorine-based particles that form a layer having a thickness of 1 to 5 μm. The intermediate transfer belt 7 is set to have an initial inner peripheral length of about 760 mm, for example.

  Here, the material constituting the transfer surface 7A (coating layer) of the intermediate transfer belt 7 is preferably a material having a hardness lower than that of an abrasive k (fluidizing agent r) described later.

In the present embodiment, a plurality of concave portions and / or a plurality of convex portions are formed on the transfer surface 7 </ b> A that is the surface of the intermediate transfer belt 7. A plurality of concave portions and / or a plurality of convex portions are formed substantially uniformly on the transfer surface 7A. That is, the transfer surface 7A is formed in a substantially uniform uneven shape.
Here, since a plurality of concave portions and / or convex portions formed substantially uniformly on the transfer surface 7A serve as a base point to which an abrasive k to be described later adheres, the abrasive k (and a fluidizing agent) is formed on the surface of the transfer surface 7A. r) adheres evenly. As a result, a layer of a polishing agent k (and a fluidizing agent r) to be described later is formed evenly (uniformly) in the planar direction.

  A predetermined portion of the intermediate transfer belt 7 is sandwiched between the primary transfer rollers 37a, 37b, 37c, and 37d and the photosensitive drums 2a, 2b, 2c, and 2d, respectively. The predetermined portion thus sandwiched is pressed against the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d. Primary transfer nips N1a, N1b, N1c, and N1d are formed between the photosensitive drums 2a, 2b, 2c, and 2d and the primary transfer rollers 37a, 37b, 37c, and 37d, respectively. In the primary transfer nips N1a, N1b, N1c, and N1d, the respective color toner images developed on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially transferred to the intermediate transfer belt 7. As a result, a full-color toner image is formed on the intermediate transfer belt 7.

  The primary transfer rollers 37a, 37b, 37c, and 37d are respectively transferred to the intermediate transfer belt 7 with the respective color toner images developed on the photosensitive drums 2a, 2b, 2c, and 2d by a voltage application unit (not shown). The primary transfer bias is applied.

  The static eliminators 12a, 12b, 12c, and 12d are arranged to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, respectively. The static eliminators 12a, 12b, 12c, and 12d respectively irradiate the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d to irradiate light, and the photosensitive drums 2a, 2b, and 2c after the primary transfer is performed. 2d, each surface is neutralized (charge is removed).

  The drum cleaning units 11a, 11b, 11c, and 11d are disposed to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, respectively. Each of the drum cleaning units 11a, 11b, 11c, and 11d removes toner and adhering matter remaining on the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, and conveys the removed toner to a predetermined recovery mechanism. And collect.

  The secondary transfer roller 8 secondarily transfers the toner image primarily transferred to the intermediate transfer belt 7 onto the paper T. A secondary transfer bias for transferring the toner image formed on the intermediate transfer belt 7 to the paper T is applied to the secondary transfer roller 8 by a voltage application unit (not shown).

  The secondary transfer roller 8 contacts or separates from the intermediate transfer belt 7. Specifically, the secondary transfer roller 8 is configured to be movable between a contact position where the secondary transfer roller 8 is in contact with the intermediate transfer belt 7 and a spaced position where the secondary transfer roller 8 is separated from the intermediate transfer belt 7. Specifically, the secondary transfer roller 8 is moved to the contact position when the toner image primarily transferred onto the surface of the intermediate transfer belt 7 is secondarily transferred to the paper T, and is separated from the other position. Moved to.

On the opposite side of the intermediate transfer belt 7 from the secondary transfer roller 8, a counter roller 18 is disposed. A predetermined portion of the intermediate transfer belt 7 is sandwiched between the secondary transfer roller 8 and the opposing roller 18. Then, the paper T is pressed against the outer surface of the intermediate transfer belt 7 (the surface on which the toner image is primarily transferred). A secondary transfer nip N <b> 2 is formed between the secondary transfer roller 8 and the opposing roller 18. The toner image primarily transferred to the intermediate transfer belt 7 is secondarily transferred to the paper T in the secondary transfer nip N2.
The secondary transfer roller 8 and the counter roller 18 are disposed on the downstream side of the photosensitive drums 2a, 2b, 2c, and 2d in the rotation direction of the intermediate transfer belt 7, and are disposed on the intermediate transfer belt 7 and the transfer surface 7A side. The toner image that has been primarily transferred is secondarily transferred onto the paper T.

The cleaning device 100 includes a main cleaning member 180 as a cleaning member and an auxiliary cleaning member 190 as a cleaning auxiliary member.
The main cleaning member 180 includes a fur brush 81, a collection roller 82, and a cleaning blade 83 (see FIGS. 2 and 3).
The main cleaning member 180 is disposed on the transfer surface 7 A side of the intermediate transfer belt 7 and on the downstream side of the secondary transfer roller 8 in the rotation direction S of the intermediate transfer belt 7. Specifically, the main cleaning member 180 is disposed at a position facing the driven roller 35 with the intermediate transfer belt 7 interposed therebetween. The main cleaning member 180 removes residual toner adhering to the transfer surface 7A of the intermediate transfer belt 7.

  The auxiliary cleaning member 190 is disposed on the transfer surface 7A side of the intermediate transfer belt 7 and on the upstream side of the main cleaning member 180 in the rotational direction S of the intermediate transfer belt 7, and remains attached to the transfer surface 7A of the intermediate transfer belt 7. Contacting the toner reduces the adhesion of the remaining toner (see FIGS. 2 and 3). Details of the cleaning device 100 will be described later.

  The fixing unit 9 melts each color toner constituting the toner image secondarily transferred onto the paper T and fixes the toner on the paper T. The fixing unit 9 includes a heating roller 9a that is heated by a heater (not shown), and a pressure roller 9b that is pressed against the heating roller 9a. The heating roller 9a and the pressure roller 9b sandwich and convey the paper T on which the toner image has been secondarily transferred. When the paper T is conveyed while being sandwiched between the heating roller 9a and the pressure roller 9b, the toner transferred onto the paper T is melted and fixed on the paper T.

Next, the paper supply / discharge unit will be described.
As shown in FIG. 1, in the lower part of the apparatus main body M, two paper feed cassettes 52 that store paper T are arranged in an up-down direction. The paper feed cassette 52 is configured to be pulled out from the housing of the apparatus main body M in the horizontal direction. In the paper feed cassette 52, a placement plate 60 on which the paper T is placed is disposed. In the paper feed cassette 52, the paper T is stored in a state of being stacked on the placement plate 60. The paper T placed on the placement plate 60 is sent out to the transport path L by the cassette paper feed unit 51 arranged at the end of the paper feed cassette 52 on the paper feed side (the left end in FIG. 1). The cassette paper feed unit 51 includes a double feed prevention mechanism including a forward feed roller 61 for taking out the paper T on the placement plate 60 and a paper feed roller pair 63 for feeding the paper T to the transport path L one by one. Prepare.

  A manual paper feed unit 64 is provided on the right side surface (right side in FIG. 1) of the apparatus main body M. The manual paper feed unit 64 is provided mainly for supplying the apparatus main body M with a paper T of a size and type different from the paper T set in the paper feed cassette 52. The manual paper feed unit 64 includes a manual feed tray 65 that forms a part of the apparatus main body M in the closed state, and a paper feed roller 66. The lower end of the manual feed tray 65 is attached to the vicinity of the paper feed roller 66 so as to be rotatable (openable and closable). The paper T is placed on the open manual feed tray 65. The manual paper feed unit 64 feeds the paper T placed on the open manual feed tray 65 to the manual feed path La.

  A first paper discharge unit 50 a and a second paper discharge unit 50 b are provided on the upper side of the apparatus main body M. The first paper discharge unit 50a and the second paper discharge unit 50b discharge the paper T to the outside of the apparatus main body M. Details of the first paper discharge unit 50a and the second paper discharge unit 50b will be described later.

  The conveyance path L for conveying the paper T includes a first conveyance path L1 from the cassette paper feeding unit 51 to the secondary transfer roller 8, a second conveyance path L2 from the secondary transfer roller 8 to the fixing unit 9, and a fixing unit. 9 is upstream of the third transport path L3 from the first paper discharge section 50a, the manual transport path La for joining the paper T supplied from the manual paper feed section 64 to the first transport path L1, and the third transport path L3. A reverse conveying path Lb that reverses the sheet T conveyed from the side to the downstream side and returns it to the first conveying path L1, and a sheet that conveys the third conveying path L3 from the upstream side to the downstream side is a post-processing device (not shown). And a post-processing conveyance path Lc.

Moreover, the 1st junction part P1 and the 2nd junction part P2 are provided in the middle of the 1st conveyance path L1. A first branch portion Q1 is provided in the middle of the third transport path L3.
The first joining part P1 is a joining part where the manual feed path La joins the first transport path L1. The second junction P2 is a junction where the return conveyance path Lb merges with the first conveyance path L1.
The first branch portion Q1 is a branch portion where the post-processing transport path Lc branches from the third transport path L3. A rectifying member 58 is provided in the first branch portion Q1. The rectifying member 58 rectifies the transport direction of the paper T carried out from the fixing unit 9 to the third transport path L3 toward the first paper discharge section 50a or the post-processing transport path Lc toward the second paper discharge section 50b ( Switch).

  A sensor (not shown) for detecting the paper T and a skew of the paper T (in the middle of the first transport path L1 (specifically, between the second joining portion P2 and the secondary transfer roller 8)) A pair of registration rollers 80 for adjusting the timing with the (oblique feeding) correction and the toner image is arranged. The sensor is disposed immediately before (on the upstream side) the registration roller pair 80 in the transport direction of the paper T. The registration roller pair 80 conveys the paper T by performing the above-described correction and timing adjustment based on detection signal information from the sensor.

  The return conveyance path Lb is a conveyance provided to make the opposite surface (non-printing surface) opposite to the already printed surface opposite to the photosensitive drums 2a, 2b, 2c, and 2d when performing duplex printing on the paper T. Road. According to the return transport path Lb, the paper T transported from the first branching section Q1 to the paper discharge section 50 is turned upside down and returned to the first transport path L1 and arranged upstream of the secondary transfer roller 8. It can be conveyed to the upstream side of the pair of registration rollers 80. A predetermined toner image is transferred onto the non-printing surface by the photosensitive drums 2a, 2b, 2c, and 2d on the paper T that has been turned upside down by the return conveyance path Lb.

  A first paper discharge unit 50a is formed at the end of the third transport path L3. The first paper discharge unit 50 a is disposed on the upper side of the apparatus main body M. The first paper discharge unit 50a is open toward the right side surface of the apparatus main body M (the right side in FIG. 1, the manual paper feed unit 64 side). The first paper discharge unit 50a discharges the paper T transported through the third transport path L3 to the outside of the apparatus main body M.

  On the opening side of the first paper discharge section 50a, a paper discharge stacking section M1 is formed. The paper discharge stacking unit M1 is formed on the upper surface (outer surface) of the apparatus main body M. The paper discharge stacking unit M1 is a part formed by the upper surface of the apparatus main body M being depressed downward. The bottom surface of the paper discharge stacking unit M1 constitutes a part of the top surface of the apparatus main body M. In the paper discharge stacking unit M1, sheets T onto which a predetermined toner image is transferred and discharged from the first paper discharge unit 50a are stacked and stacked.

A second paper discharge unit 50b is formed at the end of the post-processing conveyance path Lc. The second paper discharge unit 50b is disposed on the upper side of the apparatus main body M. The second paper discharge section 50b opens toward the left side of the apparatus main body M (left side in FIG. 1, the side to which the post-processing apparatus is connected). The second paper discharge unit 50b discharges the paper T conveyed through the post-processing conveyance path Lc to the outside of the apparatus main body M.
A post-processing device (not shown) is connected to the opening side of the second paper discharge unit 50b. The post-processing device performs post-processing (stapling, punching, etc.) of paper ejected from the image forming apparatus (copy machine 1).
A paper detection sensor is disposed at a predetermined position on each conveyance path.

Next, a paper jam (JAM) in the main transport path L1 to L3 (the first transport path L1, the second transport path L2, and the third transport path L3 are collectively referred to as “main transport path” hereinafter) and the return transport path Lb. A structure for eliminating the problem will be briefly described.
As shown in FIG. 1, on the left side surface (left side in FIG. 1) of the apparatus main body M, main conveyance paths L1 to L3 and a return conveyance path Lb are arranged in parallel so as to mainly extend in the vertical direction. A cover body 40 is provided on the left side of the apparatus body M (left side in FIG. 1) so as to form a part of the side surface of the apparatus body M. The cover body 40 is connected to the apparatus main body M via a fulcrum shaft 43 at the lower end thereof. The fulcrum shaft 43 is disposed along the direction in which the axial direction crosses the main transport paths L1 to L3 and the return transport path Lb. The cover body 40 is configured to be rotatable between a closed position (position shown in FIG. 1) and an open position (not shown) with the fulcrum shaft 43 as a center.

  The cover body 40 includes a first cover portion 41 that is rotatably connected to the apparatus main body M by a fulcrum shaft 43, and a second cover portion 42 that is rotatably connected to the apparatus main body M by the same fulcrum shaft 43. It consists of and. The first cover portion 41 is located on the outer side (side surface side) of the apparatus main body M than the second cover portion 42. In FIG. 1, the hatched portion with the left-down dashed line is the first cover portion 41, and the hatched portion with the right-down dashed line is the second cover portion 42.

In the state where the cover body 40 is located at the closed position, the outer surface side of the first cover portion 41 forms a part of the outer surface (side surface) of the apparatus main body M.
Further, in the state where the cover body 40 is located at the closed position, the inner surface side (the apparatus main body M side) of the second cover portion 42 forms a part of the main transport paths L1 to L3.
Further, in a state where the cover body 40 is located at the closed position, the inner surface side of the first cover portion 41 and the outer surface side of the second cover portion 42 form at least a part of the return conveyance path Lb. That is, the return conveyance path Lb is formed between the first cover part 41 and the second cover part 42.

  The copying machine 1 of the present embodiment includes the cover body 40 having such a configuration, so that when a paper jam (JAM) occurs in the main transport paths L1 to L3, the cover body 40 is closed as shown in FIG. By rotating from the position to an open position (not shown) to open the main transport paths L1 to L3, it is possible to process paper jammed in the main transport paths L1 to L3. On the other hand, when a paper jam occurs in the return conveyance path Lb, the cover body 40 is rotated to the open position, and then the second cover portion 42 is moved to the apparatus main body M side (right side in FIG. ) To open the return conveyance path Lb, the paper jammed in the return conveyance path Lb can be processed.

2 to 4C, the structure of the cleaning device 100, which is a characteristic part of the present invention, will be described in detail.
FIG. 2 is a diagram for explaining the configuration of the transfer unit in the color copier 1. FIG. 3 is an enlarged cross-sectional view of a main part for explaining a specific structure of the cleaning device 100. FIG. 4A is a diagram illustrating a state in which the abrasive k is attached to the transfer surface 7A of the intermediate transfer belt 7 so as to form a layer. FIG. 4B is a diagram illustrating a state in which the fluidizing agent r is further adhered to the transfer surface 7A of the intermediate transfer belt 7 to which the abrasive k is adhered in a layered manner. FIG. 4C is a view for explaining good releasability of the toner t with respect to the transfer surface 7A having the fluidizing agent r attached to the surface.

  As shown in FIGS. 2 and 3, the intermediate transfer unit 20 includes a driven roller 35, a counter roller 18, a tension roller 36, an intermediate transfer belt 7 stretched between these rollers, a primary transfer roller 37a, 37b, 37c, 37d and the cleaning device 100 are configured. The intermediate transfer unit 20 is unitized by mounting the above-described constituent members on a unit frame (not shown).

  The cleaning device 100 includes a casing 30 attached to a unit frame of the intermediate transfer unit 20, and a main cleaning member 180 and an auxiliary cleaning member 190 attached to the casing 30.

  As shown in FIG. 3, the casing 30 is installed between side plates 31, 32 that are opposed to each other in the direction perpendicular to the paper surface (front side and back side) and the lower edges of the side plates 31, 32 in FIG. 3. The bottom plate 33, the right side plate 34a laid between the right edges of the side plates 31 and 32 in FIG. 3, and the top plate 34b are provided. The casing 30 is formed with an opening on the left side (intermediate transfer belt 7 side) in FIG. The casing 30 is fixed to a unit frame (not shown) of the intermediate transfer unit 20.

As shown in FIG. 3, the main cleaning member 180 is attached to the casing 30.
The main cleaning member 180 includes a fur brush 81 that is in contact with the transfer surface 7 </ b> A of the intermediate transfer belt 7, a recovery roller 82 that is in contact with the fur brush 81, and a cleaning blade that is in sliding contact with the peripheral surface of the recovery roller 82. 83.
The main cleaning member 180 removes residual toner adhering to the transfer surface 7A of the intermediate transfer belt 7.

The fur brush 81 includes a brush shaft 811 and a fur brush body 812 that is fitted on the outer side of the brush shaft 811 and can rotate integrally with the brush shaft 811.
The fur brush body 812 is formed by uniformly planting nylon or acrylic brush hairs on the outer peripheral surface of a resin cylinder fitted on the brush shaft 811. In the present embodiment, the fur brush body 812 has an outer diameter dimension set to 15 mm. Moreover, as a bristle, what is made of nylon and has a bristle leg of 4 mm and imparted conductivity of 320T / 48F density of 150 KF / inch ² can be used.

Here, each of the plurality of brush hairs is preferably formed by integrating a plurality of fibers. Here, integration refers to twisting a plurality of fibers, fixing a plurality of bundled fibers with an adhesive, or the like.
For example, when the toner to be used is a polyester toner as the bristle, one bundle of conductive acrylic fibers that are negative in the triboelectric charging series can be molded into a single bristle.

The fur brush 81 is disposed such that the tip ends of a plurality of brush hairs abut (slidably contact) the transfer surface 7 </ b> A of the intermediate transfer belt 7.
Each of the plurality of brush bristles is in sliding contact with the transfer surface 7A of the intermediate transfer belt 7 in the rotating state.
Here, it is preferable that the plurality of brush bristles have high rigidity in the initial state and low rigidity in the state after the initial state.
The plurality of brush hairs preferably have a large contact area with the transfer surface 7A after the initial state.

With respect to the above, each of the plurality of brush bristles can be configured to have high rigidity in the initial state and low rigidity after the initial state by being formed by integrating a plurality of fibers.
A plurality of brush bristles formed by integrating a plurality of fibers (in the initial state) so as to have high rigidity can quickly form a layer of abrasive k, which is an inorganic powder, on the transfer surface 7A in the initial state. Contribute to.

Further, each of the plurality of brush bristles is slidably contacted with the intermediate transfer belt 7 having a layer of abrasive k (and fluidizing agent r) that is an inorganic powder in a rotating state. Integration in a plurality of constituent fibers is released. In other words, the tip of each of the plurality of brush bristles is in a state where a plurality of fibers are loosened.
As a result, the rigidity of the tip of each of the plurality of brush bristles is lower than that of a portion different from the tip after the initial state.
Since the integration of the plurality of fibers is released and the rigidity of the tip portion decreases, the formation of an excessive layer of the abrasive k (and the fluidizing agent r) is suppressed.

Further, the integration of the plurality of fibers constituting the tip portion is released (disengaged), whereby each of the loosened fibers is brought into sliding contact with the intermediate transfer belt 7 (transfer surface 7A).
Thus, each of the plurality of brush bristles is in sliding contact with the intermediate transfer belt 7 having the layer of the abrasive k (and the fluidizing agent r) in the initial state (the intermediate transfer belt 7 (transfer surface 7A)). It becomes larger than the contact area in the previous). Since the integration of the plurality of fibers is released and the contact area with the intermediate transfer belt 7 (transfer surface 7A) is increased, deterioration of the cleaning property due to wear of the plurality of brush hairs is suppressed. Further, since the integration of the plurality of fibers is released and the contact area with the intermediate transfer belt 7 (transfer surface 7A) is increased, the charging property to the toner is improved and the cleaning property is improved.

Further, the plurality of fibers constituting the brush bristles are made of a material having a hardness higher than that of the material constituting the surface (transfer surface 7A, coating layer) of the intermediate transfer belt 7 and a hardness lower than that of the abrasive k. The
Since the plurality of fibers constituting the bristles are harder than the material constituting the surface of the intermediate transfer belt 7 (transfer surface 7A, coating layer), the bristles are abrasive from the initial state at an early stage (short time). k can be fixed to the transfer surface 7 A of the intermediate transfer belt 7.
Further, since the plurality of fibers constituting the bristles are made of a material having a hardness lower than that of the abrasive k, after the initial state, the plurality of fibers constituting the tip are preferably loosened after the initial state. .

The collection roller 82 includes a collection roller shaft 821 and a collection roller main body 822 that is fitted on the outside of the collection roller shaft 821 so as to be concentric and can rotate integrally with the collection roller shaft 821.
The collection roller body 822 is formed of an elastomer such as rubber or soft synthetic resin. In the present embodiment, the recovery roller main body 822 has an outer diameter set to 12 mm, and an outer peripheral surface is disposed on the brush shaft side about 1.5 mm from the tip of the brush bristles with respect to the fur brush main body 812. . The collection roller main body 822 is brought into contact with a portion of the fur brush main body 812 on the tip side of the bristle.

  The brush shaft 811 of the fur brush 81 and the collection roller shaft 821 of the collection roller 82 are fixed to gears (not shown) that mesh with each other. As a result, a driving force from a driving motor (not shown) is transmitted to one gear, whereby the fur brush 81 is rotated clockwise and the collection roller 82 is rotated counterclockwise in FIG.

  The cleaning blade 83 is screwed and fixed to an inclined plate 34c extending from the left edge portion of the top plate 34b toward the lower left in FIG. The cleaning blade 83 is in sliding contact with the outer peripheral surface of the collection roller body 822 in the collection roller 82 at the free end (left end in FIG. 3). As a result, the cleaning blade 83 removes the residual toner adhering to the outer peripheral surface of the collection roller 82 (collection roller main body 822) rotating counterclockwise in FIG. In the present embodiment, the cleaning blade 83 is formed of hard urethane rubber having a thickness of 1.5 mm.

As shown in FIGS. 2 and 3, the auxiliary cleaning member 190 is disposed on the upstream side of the main cleaning member 180 in the rotational direction S of the intermediate transfer belt 7.
The auxiliary cleaning member 190 includes a stepped frame 91 that is rotatably attached to the casing 30, a brush support fitting 92 that is fixed to the stepped frame 91, and a bar brush 93 that is attached to the brush support fitting 92.
The auxiliary cleaning member 190 comes into contact with the residual toner attached to the transfer surface 7A of the intermediate transfer belt 7 and lifts the residual toner from the transfer surface 7A to reduce the adhesive force of the residual toner.

  As shown in FIG. 3, the stepped frame 91 includes a columnar member 911 extending in the vertical direction of the paper surface, and a square member shape that is disposed facing the left side of the columnar member 911 in FIG. 3 and extends in the vertical direction of the paper surface. A member 912 and a plurality of installation plates 913 provided between the columnar member 911 and the square member 912 at a predetermined interval are provided.

The length of the columnar member 911 in the vertical direction of the paper surface is set to be approximately the same as the outer dimension between the side plates 31 and 32 of the casing 30. The length of the square member 912 in the vertical direction of the paper surface is set slightly shorter than the inner dimension between the side plates 31 and 32 of the casing 30. As a result, the columnar member 911 and the square member 912 are connected to each other via the plurality of installation plates 913, and both end portions of the columnar member 911 are directed outward from the both end surfaces of the installation plate 913. Protruding.
Both end portions of the columnar member 911 are inserted through holes (not shown) formed in the side plates 31 and 32 of the casing 30. Accordingly, the stepped frame 91 is configured to be coaxial with the columnar member 911 and integrally rotatable.

The brush support bracket 92 includes a support plate portion 921, a rising plate portion 922 extending so as to extend upward from the right end portion of the support plate portion 921 in FIG. 3, and an upper end of the rising plate portion 922 in FIG. A bracket 923 extending so as to extend in the horizontal direction.
The brush support bracket 92 is fixed to the stepped frame 91 by fixing the bracket 923 to a position corresponding to the installation plate 913 via a screw.
The brush support fitting 92 is attached such that the support plate portion 921 is on the transfer surface 7A of the intermediate transfer belt 7 and faces the portion immediately before the portion corresponding to the driven roller 35.

  The bar brush 93 includes a base sheet 931, a large number of brush hairs 932 implanted on one surface (the lower surface side in FIG. 3) of the base sheet 931, and the base sheet 931 as a brush support fitting 92 (support plate portion 921). And a double-sided tape 933 to be adhered to.

In the present embodiment, as the bristle 932, one made of PET (Polyethylene terephthalate), having a bristle leg of 4 mm, and a 280T / 48F density of 80 KF / inch ² can be used.
The bar brush 93 is arranged to face the transfer surface 7A so that the distance between the base sheet 931 and the transfer surface 7A of the intermediate transfer belt 7 is about 1.5 mm shorter than the length of the brush bristles 932. The bar brush 93 is arranged such that the tip side of the bristle 932 is in contact with the transfer surface 7A.

The brush bristles 932 of the bar brush 93 in the auxiliary cleaning member 190 are coated (included) with an abrasive and / or a fluidizing agent as an inorganic powder in the initial state. The abrasive and fluidizing agent as the inorganic powder are preferably the same as the abrasive and fluidizing agent contained in the toner (externally added).
As an abrasive, for example, alumina (aluminum oxide), magnetite, cerium oxide, titanium oxide, magnesium oxide, silicon carbide, silicon nitride, sodium silicate, potassium silicate, magnesium silicate, aluminum silicate (calcined clay), Examples thereof include fine particles such as calcium sulfate, barium sulfate, aluminum sulfate, and calcium carbonate, and those obtained by subjecting these inorganic fine particles to a hydrophobic treatment with a silicone oil or a silane coupling agent. The abrasive has an average particle size of 0.05 to 5 μm, preferably 0.2 to 0.6 μm.

  Examples of the fluidizing agent include fine particles of metal oxides such as silica, alumina, titania, titanium oxide, calcium oxide, barium oxide, beryllium oxide, zinc oxide, and tin oxide, and fine particles of these metal oxides with silicone oil or The thing hydrophobized with the silane coupling agent etc. is mentioned. The fluidizing agent has an average particle size of 0.1 μm or less and about 1/5 to 1/200, preferably about 1/10 to 1/100 of the average particle size of the abrasive.

The “initial state” is a state before the toner image is primarily transferred to the intermediate transfer belt 7. For example, it refers to a state after the assembly of the intermediate transfer unit 20 (before shipment) or after shipment and before operation.
Here, before the primary transfer of the toner image to the intermediate transfer belt 7, the color copier 1 in this embodiment can apply inorganic powder (fluidizing material, abrasive) to the transfer surface 7 </ b> A. Specific examples in the case where the inorganic powder is an abrasive are as follows.

  First, in the initial state, the intermediate transfer belt 7 is rotated for a predetermined time (for example, about 30 seconds). As a result, the abrasive k applied to the bristles 932 of the bar brush 93 in the auxiliary cleaning member 190 is transferred to the transfer surface 7A of the intermediate transfer belt 7. At this time, since the abrasive k is rubbed by the brush bristles 932 of the bar brush 93, it adheres so as to pierce the transfer surface 7A as shown in FIG. 4A. The abrasive k moves to the transfer surface 7A and adheres so as to form a layer having a substantially uniform thickness on the surface of the transfer surface 7A (a region where the brush bristles 932 abut).

Here, as described above, a plurality of concave portions and / or a plurality of convex portions are formed on the transfer surface 7 </ b> A which is the surface of the intermediate transfer belt 7. A plurality of concave portions and / or a plurality of convex portions are formed on the transfer surface 7A so as to be substantially uniform. That is, the transfer surface 7A is formed in a substantially uniform uneven shape.
Here, the interval between the tips of the convex portions is preferably 125 μm or less. Further, the ten-point average roughness Rz is preferably larger than the average particle diameter of the external additive and smaller than the average particle diameter of the toner.
Since the plurality of concave portions and / or convex portions formed substantially uniformly on the transfer surface 7A serve as a base point to which the abrasive k described later adheres, the abrasive k (and the fluidizing agent r) is applied to the surface of the transfer surface 7A. Adheres evenly.
As a result, a layer of a polishing agent k (and a fluidizing agent r) to be described later is formed evenly (uniformly) in the planar direction.

  By forming the layer of the abrasive k on the transfer surface 7A, the fluidizing agent r easily adheres to the surface of the layer of the abrasive k. That is, as shown in FIG. 4B, a layer of fluidizing agent r excellent in toner releasability is formed on the surface of the layer of abrasive k as shown in FIG. 4B.

  For example, the color copying machine 1 forms the surface treatment of the intermediate transfer belt 7 (specifically, the layer of abrasive k and / or the layer of fluidizing agent r on the transfer surface 7A in the initial state as described above. (Hereinafter referred to as “pre-coating”), the product is shipped and subjected to a normal image forming action. Hereinafter, the image forming operation will be briefly described.

  First, the lid member 70 (see FIG. 1) is opened, and the document G is placed on the reading surface 302A (see FIG. 1). When the optical sensor 362 (see FIG. 1) detects that a document is placed on the reading surface 302A, the illumination unit and the mirror unit are arranged on the left side of the housing 306 (left side in FIG. 1). The

  Next, the lid member 70 is closed. Then, by pressing a start switch (not shown), the color copying machine 1 is instructed to duplicate the image of the original G. By pressing the start switch, the image reading apparatus 300 starts reading an image of the original G.

  Specifically, first, a plurality of LEDs in the LED unit are turned on. The light emitted from the plurality of lit LEDs irradiates the document reading position R at a predetermined angle. Accordingly, the original reading position R is irradiated with line-shaped light extending in the main scanning direction Y from both sides in the sub-scanning direction X.

  Each of the illumination unit and the mirror unit moves in the sub-scanning direction X in a state where the document reading position is irradiated with light. Each of the illumination unit and the mirror unit moves while keeping the optical path length in the optical path H constant.

  The light beam from the original G is reflected by the first mirror 321, the second mirror 322, and the third mirror 323, and then enters the imaging lens 357 (see FIG. 1).

  The imaging lens 357 forms an image of the original G on the light receiving surface of the CCD 358. The CCD 358 converts the image information of the original G formed on the light receiving surface into an electric signal and reads it (see FIG. 1).

  Image information read by the CCD 358 is output to the CCD substrate 361. The image information output to the CCD substrate 361 is output to the apparatus main body M through a predetermined circuit board (see FIG. 1).

  In the apparatus main body M, the input image information is input to an image formation control unit (not shown). Based on the image information, the image forming control unit includes the photosensitive drums 2a to 2d as the image carrier constituting the image forming unit, the charging units 10a to 10d, the laser scanner units 4a to 4d, the developing devices 16a to 16d, and the like. By controlling, electrostatic latent images are formed on the photosensitive drums 2a, 2b, 2c, and 2d, and yellow, cyan, magenta, and black toners are attached to these electrostatic latent images to form a color toner image. Development is performed (a toner image is formed on the surface of the photosensitive drum (see FIG. 1)).

  Subsequently, predetermined portions of the intermediate transfer belt 7 sandwiched between the photosensitive drums 2a, 2b, 2c, and 2d and the primary transfer rollers 37a, 37b, 37c, and 37d are the photosensitive drums 2a, 2b, and 2c. 2d, the primary transfer nips N1a and N1b formed between the photosensitive drums 2a, 2b, 2c, and 2d and the primary transfer rollers 37a, 37b, 37c, and 37d, respectively. , N1c, and N1d, the respective color toner images developed on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially primarily transferred onto the transfer surface 7A of the intermediate transfer belt 7, respectively. As a result, a full-color toner image is formed on the intermediate transfer belt 7.

  A predetermined portion of the intermediate transfer belt 7 and the paper T are sandwiched between the secondary transfer roller 8 and the opposing roller 18, and the paper T is transferred to the transfer surface 7A of the intermediate transfer belt 7 (the surface on which the toner image is primarily transferred). The full-color toner image formed on the transfer surface 7A of the intermediate transfer belt 7 is applied to the sheet T at the secondary transfer nip N2 formed between the secondary transfer roller 8 and the opposing roller 18 by being pressed. Next transferred.

  The sheet T onto which the toner image has been secondarily transferred is conveyed to the fixing unit 9 through the second conveying path L2, and is sandwiched between the heating roller 9a and the pressure roller 9b in the fixing unit 9. , The toner secondarily transferred onto the paper T is melted and the image is fixed on the paper T.

  The sheet T on which the same image as the image of the original G is transferred and fixed based on the image information is branched at the first branching portion Q1, and the main body of the apparatus from the third transport path L3 side and the first paper discharge portion 50a. The paper is discharged and collected in a paper discharge stacking unit M1 outside M, or is transported on the post-processing transport path Lc side and discharged to the outside of the apparatus main body M.

As described above, the color copier 1 in the present embodiment continuously performs normal image forming processing after the surface processing (pre-coating) on the intermediate transfer belt 7 is completed.
In the image forming process, the color copier 1 continuously forms a toner image with toner to which a fluidizing agent r or the like is added on the transfer surface 7A of the intermediate transfer belt 7. By the continuous image forming process, a layer (see FIG. 4B) of the fluidizing agent r is formed on the transfer surface 7A of the intermediate transfer belt 7 on the previously formed layer of the abrasive k (see FIG. 4A). The Here, since the layer of the abrasive k is already formed substantially uniformly, the fluidizing agent r preferably migrates (adheres) to the surface of the transfer surface 7A (the layer of the abrasive k).
When the toner image is primarily transferred to the transfer surface 7A on which the layer of the fluidizing agent r is formed, the toner particles are easily peeled off from the transfer surface 7A as shown in FIG. 4C.

  As a result, in the color copying machine 1 according to the present embodiment, the additive (for example, inorganic powder such as an abrasive or a fluidizing agent) contained in the toner adheres to the transfer surface 7A of the intermediate transfer belt 7 in a streak shape. Due to the difference in transfer efficiency between the portion where the agent is present (the streak portion) and the portion where the additive is not present, it is possible to suppress the occurrence of streaky density unevenness and omission in the toner image transferred onto the paper T. .

Here, a specific description will be given below with reference to examples.
<First embodiment>
Titanium oxide (abrasive) is applied as inorganic powder to the bristle 932 of the bar brush 93 in the auxiliary cleaning member 190 having the specifications (dimensions, material, etc.) described in the embodiment, and the number of printed sheets is 1,500, 1000, 2000. The whitening on the transfer surface 7A of the intermediate transfer belt 7 and the images obtained were evaluated when the number reached 5000, 10,000, 20000, 50000, and 100,000 (sheets).
<First comparative example>
The whitening on the transfer surface 7A of the intermediate transfer belt 7 when the number of printed sheets reaches the same number as in the embodiment without applying inorganic powder to the brush bristles 932 of the bar brush 93 in the auxiliary cleaning member 190 having the specifications described in the embodiment. The obtained images were evaluated.
The durable print chart used was a color chart of 5% coverage for each color of yellow, cyan, magenta, and black, and a 600 DPI dot image was used as the unevenness inspection image.

FIG. 5 is a table showing the relationship between the number of printed sheets, whitening, and image evaluation in the first example and the first comparative example.
As shown in FIG. 5, in the case of the first comparative example, the image evaluation is ○ when the number of printed sheets is from 1 to 1000, × from 2000 to 100,000 (no unevenness and missing), and 20000 to 100,000. It turns out that the number of sheets is ○. In the whitening evaluation, it was found that the number of printed sheets was 1 (no whitening), 500 to 20000 was x, and 50,000 to 100,000 was Δ.
As a result, in the case of the first comparative example, after the operation is started (first sheet), the image is good without whitening, but the whitening of the transfer surface 7A starts after printing a predetermined number of sheets (500 sheets), and a predetermined number of sheets are printed. Later (2000 sheets), unevenness and omission in the image occur, and the image becomes uneven in a considerable number of sheets (number of printed sheets while the image is x: 18000 sheets) until returning to a state where the image becomes good (20000 sheets) again. It has been found that there is a possibility of omission.

  As shown in FIG. 5, in the case of the first example, the image evaluation was “good” (no unevenness or omission) in any number of printed sheets. In the whitening evaluation, the first sheet was x (whitening, streaks), and all the 500 sheets and thereafter were Δ (whitening, relatively uniform), but the obtained images were good for any number of printed sheets. I found out.

<Second embodiment>
As in the first example, titanium oxide (abrasive) is applied as an inorganic powder to the brush bristles 932 of the bar brush 93 in the auxiliary cleaning member 190 having the specifications (dimensions, material, etc.) described in the embodiment, and intermediate transfer is performed. The whitening (titanium oxide layer), cleaning properties, etc. on the transfer surface 7A of the belt 7 were observed over time.

<Example A>
As Example A, the formation (whitening) state of the titanium oxide layer and the like were confirmed by a color copier having the following configuration. In each component or the like, the specifications not defined below are the specifications described in the embodiment as in the first example.
Intermediate transfer belt: Coating layer: formed using PTFE resin dispersion coating agent Primary transfer roller: Roller with EPDM rubber arranged on the outer periphery Secondary transfer roller: Roller with epichlorohydrin rubber arranged on the outer periphery Toner: Polyester resin, positive electrode made of silica Side charged, spheroidized
Brush hair containing titanium oxide as abrasive: Conductive acrylic fiber
Integrated treatment of multiple conductive acrylic fibers

As a result of observation, a layer of the abrasive k was formed on the surface of the transfer surface of the intermediate transfer belt in a short time from the initial state (whitened). Since the bristle constituting the fur brush is formed by further integrating highly rigid acrylic fibers, a titanium oxide layer was formed on the surface of the intermediate transfer belt in a short time from the initial state.
Further, after the initial state (after the titanium oxide layer was formed on the entire transfer surface), the titanium oxide layer formed on the surface of the transfer surface was not excessively formed and maintained in a constant state. The fibers at the tip of the brush bristles constituting the fur brush are loosened, and the tip is reduced in rigidity, so that an excessive formation (excessive whitening) of the titanium oxide layer is suppressed.

  Further, after the initial state, the cleaning property was maintained (decrease in cleaning property was suppressed). The fibers at the tip of the brush bristles constituting the fur brush are loosened, and each of the plurality of fibers is slidably contacted with the transfer surface of the intermediate transfer belt, thereby increasing the contact area of the brush bristles with the intermediate transfer belt and the toner. The chargeability to is improved. Thereby, the cleaning property in the fur brush was maintained.

<Example B>
In addition to the conditions of Example A, the surface of the intermediate transfer belt was set to the following conditions.
Intermediate transfer belt: Coating layer: Molding the transfer surface into a concavo-convex shape As a result of observation, as in Example A, the transfer surface of the intermediate transfer belt is whitened in a short time from the initial state, and the cleaning property after the initial state is also maintained. It was done.
In addition, a titanium oxide layer was uniformly formed on the surface of the transfer surface of the intermediate transfer belt in a short time from the initial state (uniformly whitened). A uniform titanium oxide layer was formed in a short time from the initial state by fixing titanium oxide on the surface of the transfer belt based on a plurality of concave portions (or convex portions) uniformly formed on the surface of the transfer surface. .

<Example C>
Based on the conditions of Example B, the conditions in the coating layer of the intermediate transfer belt were changed to the following conditions.
Intermediate transfer belt: Coating layer: formed using a urethane acrylic coating agent As a result of observation, as in Example A, the transfer surface of the intermediate transfer belt is whitened in a short time from the initial state, and cleaning properties after the initial state Was also maintained.
As in Example B, the transfer surface of the intermediate transfer belt was uniformly whitened in a short time from the initial state.
The coating layer constituting the surface of the transfer surface is lower in hardness than titanium oxide and lower in hardness than acrylic fibers used for brush bristles. For this reason, since the titanium oxide is fixed to the coating layer on the transfer surface in a short time from the initial state, the titanium oxide layer was suitably formed (whitened) at an early stage.
Moreover, the acrylic resin which comprises a brush hair is lower hardness than a titanium oxide. For this reason, after the initial state, the tip of the fur brush is suitably loosened, so that the cleaning property is maintained.

As described above, according to the present embodiment, the following effects are achieved.
According to the present embodiment, the auxiliary cleaning member 190 disposed on the transfer surface 7A side of the intermediate transfer belt 7 and on the upstream side of the main cleaning member 180 is an inorganic material composed of an abrasive and / or a fluidizing agent in the initial state. Has powder.
Thus, the inorganic powder can be easily applied to the transfer surface 7A before the toner image is transferred. This also suppresses the occurrence of streak-like density unevenness or omission in the image transferred to the paper T, and a good image can be obtained.

Further, according to the present embodiment, the intermediate transfer belt 7 is rotated for a predetermined time in the initial state, thereby transferring the inorganic powder to the transfer surface 7A side, and transferring the layer of the abrasive and / or the fluidizing agent. It can be formed on the surface 7A.
Thereby, it is not necessary to apply the inorganic powder to the transfer surface 7A of the intermediate transfer belt 7 by a manual operation or a dedicated device, and it is possible to reduce the work burden and the manufacturing cost burden.

  In addition, according to the present embodiment, as the fur brush, the intermediate transfer belt can be used in a short time (early) from the initial state by using a fur brush composed of brush hair in which a plurality of fibers are integrated (aggregated). In addition, an inorganic powder (abrasive, fluidizing agent) layer can be formed on the surface of the substrate, and excessive formation of the inorganic powder layer after the initial state can be suppressed. Thereby, it is possible to suppress the occurrence of streaky density unevenness or omission in the image transferred to the paper T, and to obtain a good image.

  Further, according to the present embodiment, by using a fur brush composed of brush hairs in which a plurality of fibers are integrated (aggregated) as the fur brush, the cleaning property can be maintained after the initial state (cleaning) Can reduce the decline in sex).

  In addition, according to the present embodiment, by forming a plurality of concave portions and / or convex portions on the transfer surface (coating layer) of the intermediate transfer belt, an inorganic powder layer can be uniformly formed on the transfer surface. . Thereby, it is possible to suppress the occurrence of streaky density unevenness or omission in the image transferred to the paper T, and to obtain a good image.

Further, according to the present embodiment, the plurality of fibers constituting the brush bristles are harder than the material constituting the surface of the intermediate transfer belt 7 (transfer surface 7A, coating layer) and lower than the abrasive k. Consists of materials that are hardness.
As a result, the layer of the inorganic powder is uniformly formed on the transfer surface early (short time) from the initial state, and after the initial state, the plurality of fibers constituting the tip are suitably loosened and excessively Formation of an inorganic powder layer and a decrease in cleaning properties are suppressed.

  As mentioned above, although preferred embodiment was described, this invention can be implemented with a various form, without being limited to embodiment mentioned above. For example, in the present embodiment, the color copying machine 1 is described as the image forming apparatus, but the present invention is not limited to this, and may be a monochrome copying machine, a printer, a facsimile machine, or a multifunction machine of these.

  In this embodiment, only the abrasive is applied as the inorganic powder to be applied to the brush bristles 932 of the bar brush 93 in the auxiliary cleaning member 190. However, the present invention is not limited to this. Agents and fluidizing agents may be applied.

  In the present embodiment, as the inorganic powder to be applied to the brush bristles 932 of the bar brush 93 in the auxiliary cleaning member 190 in the initial state, the same as the powder abrasive and fluidizing agent contained (added externally) in the toner. Although the thing was used, it is not limited to this, Another kind of abrasive | polishing agent and fluidizing agent which are not contained in a toner may be used.

  DESCRIPTION OF SYMBOLS 1 ... Color copier (image forming apparatus), 2a, 2b, 2c, 2d ... Photosensitive drum (image carrier), 7 ... Intermediate transfer belt (transfer part), 7A ... Transfer surface, 8 ... Secondary transfer roller, 9... Fixing section, 16 a, 16 b, 16 c, 16 d... Developer, 18 .. opposing roller (secondary transfer roller), 37 a, 37 b, 37 c, 37 d. ...... Main cleaning member (cleaning member), 190 ... auxiliary cleaning member (cleaning auxiliary member), T .... paper (transferred material), k .... abrasive, r .... fluidizing agent, t .... toner

Claims (9)

One or more image carriers having electrostatic latent images formed on the surface;
One or more developing devices for developing a toner image on the electrostatic latent image formed on the one or more image carriers;
A ring-shaped intermediate transfer belt that is rotatable in the ring direction, and having a transfer surface on which a toner image formed by the one or more image carriers is primarily transferred;
The intermediate transfer belt is disposed on the downstream side of the one or more image carriers, and the intermediate transfer belt and the sheet-shaped transfer material disposed on the transfer surface side are sandwiched to perform the primary transfer. A pair of secondary transfer rollers for secondary transfer of the toner image to the transfer material;
A cleaning member that is disposed on the transfer surface side of the intermediate transfer belt and downstream of the secondary transfer roller in the rotational direction, and removes residual toner attached to the transfer surface;
A cleaning auxiliary member that is disposed on the transfer surface side of the intermediate transfer belt and upstream of the cleaning member in the rotational direction, and reduces the adhesion of the residual toner by contacting the residual toner adhering to the transfer surface. An image forming apparatus comprising: a cleaning auxiliary member having one or more inorganic powders in an initial state. The image forming apparatus according to claim 1, wherein a plurality of concave portions and / or convex portions are formed on the transfer surface of the intermediate transfer belt. 3. The cleaning auxiliary member can form the inorganic powder layer by rotating the intermediate transfer belt in an initial state to transfer the inorganic powder to the surface of the transfer surface. The image forming apparatus described. The intermediate transfer belt is a layer of inorganic powder formed on the transfer surface, and is formed by inorganic powder transferred from the cleaning auxiliary member by rotating the intermediate transfer belt in an initial state. The image forming apparatus according to claim 1, further comprising a body layer. The image forming apparatus according to claim 1, wherein the inorganic powder is a fluidizing agent and / or an abrasive contained in toner. The cleaning member includes a fur brush having a plurality of brush bristles in sliding contact with the intermediate transfer belt,
The image forming apparatus according to claim 1, wherein each of the plurality of brush bristles is formed by integrating a plurality of fibers. Each of the plurality of brush bristles is in sliding contact with the intermediate transfer belt having a layer of the inorganic powder in a rotating state at a tip end portion thereof.
The leading end portion is released from the integration of the plurality of fibers constituting the leading end portion, has a lower rigidity than a portion different from the leading end portion, and has the inorganic powder layer to the intermediate transfer belt. The image forming apparatus according to claim 6, wherein the contact area is configured to be larger than a contact area in an initial state. The plurality of fibers constituting the bristles are made of a material having a hardness higher than that of the material constituting the surface of the intermediate transfer belt and a hardness lower than that of the inorganic powder. Image forming apparatus. A surface treatment method for an intermediate transfer belt, wherein an inorganic powder layer is formed on the transfer surface of the intermediate transfer belt in the image forming apparatus according to claim 1,
Intermediate transfer comprising a step of rotating the intermediate transfer belt for a predetermined time in an initial state to transfer the inorganic powder of the cleaning auxiliary member to the surface of the transfer surface to form the inorganic powder layer. Belt surface treatment method.

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