JP2021051254A - Cleaning device and image forming apparatus - Google Patents

Abstract

To provide a cleaning device that can appropriately remove a foreign substance remaining on a member to be cleaned.SOLUTION: A cleaning device has: a member to be cleaned that has a plurality of projections and depressions formed on its surface; a plate-like first cleaning member that is configured to contact the surface of the member to be cleaned and has elasticity; and a second cleaning member that is arranged on the downstream side of the first cleaning member in a direction of movement of the member to be cleaned and is configured to contact the surface of the member to be cleaned on which the plurality of projections and depressions are formed. On a cross section along the direction of movement of the member to be cleaned, the shape of a leading end of the second cleaning member is a shape that is inserted into a concave part between adjacent two convex parts of the member to be cleaned.SELECTED DRAWING: Figure 3

Description

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

Generally, an electrophotographic image forming apparatus (printer, copier, facsimile, etc.) forms an electrostatic latent image by irradiating (exposing) a charged photoconductor with a laser beam based on image data. .. Then, by supplying toner to the photoconductor on which the electrostatic latent image is formed, the electrostatic latent image is visualized and a toner image is formed. Further, after the toner image is transferred to the recording medium via the intermediate transfer body, the image is formed on the recording medium by heating, pressurizing and fixing.

In such an image forming apparatus, the toner remaining on the photoconductor or the intermediate transfer body (member to be cleaned) is removed by the cleaning apparatus (see, for example, Patent Document 1).

Patent Document 1 describes a cleaning device for removing toner remaining on a member to be cleaned. The cleaning device described in Patent Document 1 includes an elastic cleaning member arranged on the upstream side in the moving direction of the member to be cleaned, and a non-deformable cleaning member arranged on the downstream side in the moving direction of the member to be cleaned. In the cleaning device described in Patent Document 1, the toner is roughly removed by the elastic cleaning member, and then the toner that cannot be completely removed by the elastic cleaning member is removed by the non-deformable cleaning member.

Further, in the image forming apparatus as described above, the amount of toner adhering to the surface of the member to be cleaned is optically detected by a sensor. In this case, the incident light and the reflected light emitted from the light emitting side of the sensor interfere with each other, so that noise is generated on the light receiving side of the sensor, and the amount of residual toner adhered may not be measured accurately. On the other hand, an intermediate transfer body that prevents interference between incident light and reflected light is known (see, for example, Patent Document 2).

Patent Document 2 describes an intermediate transfer body having a base material layer and a surface layer formed on the base material layer. A plurality of irregularities are formed on the surface layer, and the ten-point average roughness Rz of the surface of the surface layer is 0.6 μm or more and 1.3 μm or less. In the intermediate transfer body described in Patent Document 2, the unevenness formed on the surface layer is kept within a predetermined range to scatter light and prevent interference between incident light and reflected light.

Japanese Unexamined Patent Publication No. 2002-278319 JP-A-2017-245260

Here, it is conceivable that the cleaning apparatus described in Patent Document 1 removes the residual toner on the intermediate transfer body described in Patent Document 2. However, Patent Document 1 does not describe an intermediate transcript as described in Patent Document 2, and Patent Document 2 does not describe a cleaning device as described in Patent Document 1. There is still room for consideration in properly removing the toner remaining on the intermediate transfer material. In particular, in the intermediate transfer body described in Patent Document 2, toner enters between two adjacent convex portions (concave portions), and the cleaning member cannot remove the toner remaining on the surface of the intermediate transfer body, resulting in poor cleaning performance. It is possible that it will decrease.

The present invention is to provide a cleaning device and an image forming device capable of appropriately removing foreign matters remaining on a member to be cleaned.

The cleaning device as one means for solving the above-mentioned problems is a cleaning device for cleaning a member to be cleaned which has a plurality of irregularities formed on the surface and moves in one direction, and is a cleaning device for cleaning the member to be cleaned. A plate-shaped first cleaning member configured to be in contact with the surface and having elasticity, and the surface of the member to be cleaned, which is arranged downstream of the first cleaning member in the moving direction of the member to be cleaned. It has a second cleaning member configured to come into contact with each other, and in a cross section along the moving direction of the member to be cleaned, the tip shape of the second cleaning member is two adjacent convex portions of the member to be cleaned. It has a shape that fits into the recess between them.

The image forming apparatus as one means for solving the above-mentioned problems is an electrophotographic image forming apparatus, in which a plurality of irregularities are formed on the surface and the member to be cleaned moves in one direction, and the subject to be cleaned. The plate-shaped first cleaning member, which is in contact with the surface of the cleaning member and has elasticity, is in contact with the surface of the member to be cleaned, and is arranged downstream of the first cleaning member in the moving direction of the member to be cleaned. An image forming apparatus having the second cleaning member, and in a cross section along the moving direction of the member to be cleaned, the tip shape of the second cleaning member is two adjacent convex portions of the member to be cleaned. The member to be cleaned is an image carrier on which a toner image is carried.

According to the present invention, it is possible to provide a cleaning device and an image forming device capable of appropriately removing foreign matters remaining on the member to be cleaned.

FIG. 1 is a diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing a main part of a control system of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram showing a configuration of a cleaning device according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing the configuration of the intermediate transfer belt. 5A to 5C are schematic views showing an example of an arcuate configuration.

Hereinafter, the cleaning device according to the embodiment of the present invention and the image forming device having the cleaning device will be described in detail with reference to the attached drawings.

FIG. 1 is a diagram showing a configuration of an image forming apparatus 1 according to an embodiment of the present invention. FIG. 2 is a diagram showing a main part of a control system of the image forming apparatus 1 according to the embodiment of the present invention.

As shown in FIGS. 1 and 2, the image forming apparatus 1 is an intermediate transfer type color image forming apparatus utilizing electrophotographic process technology. That is, the image forming apparatus 1 transfers each color toner image of Y (yellow), M (magenta), C (cyan), and K (black) formed on the photoconductor drum 413 to the intermediate transfer belt (intermediate transfer body) 421. An image is formed by primary transfer to (member to be cleaned), superimposing toner images of four colors on an intermediate transfer belt 421, and then secondary transfer to paper S (recording medium). The image forming apparatus 1 may be an apparatus for forming a monochrome image (for example, a monochrome image).

In the image forming apparatus 1, the photoconductor drums 413 corresponding to the four colors of YMCK are arranged in series in the traveling direction of the intermediate transfer belt 421, and the toner images of each color are sequentially transferred to the intermediate transfer belt 421 in a single procedure. Has been adopted.

The image forming apparatus 1 includes an image reading unit 10, an operation display unit 20, an image processing unit 30, an image forming unit 40, a paper transport unit 50, a fixing unit 60, and a control unit 100.

The control unit 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, and a RAM (Random Access Memory) 103. The CPU 101 reads a program according to the processing content from the ROM 102, develops it in the RAM 103, and centrally controls the operation of each block of the image forming apparatus 1 in cooperation with the expanded program. At this time, various data stored in the storage unit 72 are referred to. The storage unit 72 is, for example, a non-volatile semiconductor memory (so-called flash memory) or a hard disk drive.

The control unit 100 transmits and receives various data to and from an external device (for example, a personal computer) connected to a communication network such as a LAN (Local Area Network) or WAN (Wide Area Network) via the communication unit 71. Do. The control unit 100 receives, for example, image data transmitted from an external device, and causes the paper S to form an image based on the image data (input image data). The communication unit 71 is a communication control card such as a LAN card.

The image reading unit 10 includes an automatic document feeding device 11 called an ADF (Auto Document Feeder) and a document image scanning device 12 (scanner).

The automatic document feeding device 11 conveys the document D placed on the document tray by the conveying mechanism and sends it out to the document image scanning device 12. The automatic document feeding device 11 can continuously read a large number of images (including both sides) of the documents D placed on the document tray at once.

The document image scanning device 12 optically scans the document conveyed on the contact glass from the automatic document feeding device 11 or the document placed on the contact glass, and the reflected light from the document is a CCD (Charge Coupled Device). ) An image is formed on the light receiving surface of the sensor 12a, and the original image is read. The image reading unit 10 generates input image data based on the scanning result by the original image scanning device 12. The image processing unit 30 performs predetermined image processing on the input image data.

The operation display unit 20 is, for example, a liquid crystal display (LCD) with a touch panel, and also functions as a display unit 21 and an operation unit 22. The display unit 21 displays various operation screens, an image status display, an operation status of each function, and the like according to a display control signal input from the control unit 100. The operation unit 22 has various operation keys such as a numeric keypad and a start key, receives various input operations by the user, and outputs an operation signal to the control unit 100.

The image processing unit 30 includes a circuit that performs digital image processing according to initial settings or user settings on the input image data. The image processing unit 30 performs gradation correction based on the gradation correction data (gradation correction table) under the control of the control unit 100, for example. Further, the image processing unit 30 performs various correction processes such as gradation correction, color correction, and shading correction, and compression processing on the input image data. The image forming unit 40 is controlled based on the image data subjected to these processes.

The image forming unit 40 includes an image forming unit 41Y, 41M, 41C, 41K and an intermediate transfer unit for forming an image with each colored toner of Y component, M component, C component, and K component based on the input image data. It has 42 and.

The image forming units 41Y, 41M, 41C, and 41K for the Y component, the M component, the C component, and the K component have the same configuration. In the following description, for convenience of illustration and description, common components are indicated by the same reference numerals, and when they are distinguished from each other, they are indicated by adding Y, M, C, or K to the reference numerals. In FIG. 1, the reference numerals are given only to the components of the image forming unit 41Y for the Y component, and the reference numerals are omitted for the other components of the image forming units 41M, 41C, and 41K.

The image forming unit 41 includes an exposure device 411, a developing device 412, a photoconductor drum (image carrier) 413, a charging device 414, and a drum cleaning device 415.

The exposure device 411 is, for example, a semiconductor laser, and irradiates the photoconductor drum 413 with a laser beam corresponding to an image of each color component. As a result, an electrostatic latent image of each color component is formed on the surface of the photoconductor drum 413 due to the potential difference from the surroundings.

The developing device 412 is, for example, a two-component reversing type developing device, and by adhering toner of each color component to the surface of the photoconductor drum 413, an electrostatic latent image is visualized to form a toner image. The developing apparatus 412 has a developing sleeve arranged so as to face the photoconductor drum 413 with the developing region interposed therebetween. For example, a DC development bias having the same polarity as the charging polarity of the charging device 414 or a development bias in which a DC voltage having the same polarity as the charging polarity of the charging device 414 is superimposed on the AC voltage is applied to the developing sleeve. As a result, reverse development is performed in which toner is adhered to the electrostatic latent image formed by the exposure apparatus 411.

The photoconductor drum 413 is, for example, an organic photoconductor in which a resin photosensitive layer containing an organic photoelectric conductor is formed on an outer peripheral surface of a drum-shaped metal substrate.

The control unit 100 rotates the photoconductor drum 413 at a constant peripheral speed by controlling the drive current supplied to the drive motor (not shown) that rotates the photoconductor drum 413.

The charging device 414 is, for example, a charging charger, and by generating a corona discharge, the surface of the photoconductor drum 413 having photoconductivity is uniformly charged to the negative electrode property.

The drum cleaning device 415 has a flat plate-shaped drum cleaning blade made of an elastic body that is in contact with the surface of the photoconductor drum 413, and remains on the surface of the photoconductor drum 413 without being transferred to the intermediate transfer belt 421. Remove the toner.

The intermediate transfer unit 42 includes a primary transfer roller 422, a plurality of support rollers 423, a secondary transfer roller 424, and a belt cleaning device (cleaning device) 426 including an intermediate transfer belt 421.

The primary transfer roller 422 is arranged on the inner peripheral surface side of the intermediate transfer belt 421 so as to face the photoconductor drum 413 of each color component. By pressing the primary transfer roller 422 against the photoconductor drum 413 with the intermediate transfer belt 421 sandwiched between them, a primary transfer nip for transferring the toner image from the photoconductor drum 413 to the intermediate transfer belt 421 is formed.

The secondary transfer roller 424 is arranged on the outer peripheral surface side of the intermediate transfer belt 421 so as to face the backup roller 423B arranged on the downstream side of the roller 423A in the belt traveling direction. By pressing the secondary transfer roller 424 against the backup roller 423B with the intermediate transfer belt 421 sandwiched between them, a secondary transfer nip for transferring the toner image from the intermediate transfer belt 421 to the paper S is formed.

When the intermediate transfer belt 421 passes through the primary transfer nip, the toner image on the photoconductor drum 413 is sequentially superimposed on the intermediate transfer belt 421 and the primary transfer is performed. Specifically, a primary transfer bias is applied to the primary transfer roller 422, and a charge having a polarity opposite to that of the toner is applied to the back surface side (the side that contacts the primary transfer roller 422) of the intermediate transfer belt 421 to obtain a toner image. It is electrostatically transferred to the intermediate transfer belt 421.

After that, when the paper S passes through the secondary transfer nip, the toner image on the intermediate transfer belt 421 is secondarily transferred to the paper S. Specifically, a secondary transfer bias is applied to the secondary transfer roller 424, and a charge having a polarity opposite to that of the toner is applied to the back surface side of the paper S (the side that comes into contact with the secondary transfer roller 424) to obtain a toner image. Is electrostatically transferred to the paper S. The paper S on which the toner image is transferred is conveyed toward the fixing portion 60.

The belt cleaning device 426 removes the transfer residual toner remaining on the surface of the intermediate transfer belt 421 after the secondary transfer. The intermediate transfer belt 421 is composed of an endless belt, and is stretched in a loop on a plurality of support rollers 423. At least one of the plurality of support rollers 423 is composed of a driving roller, and the other is composed of a driven roller. For example, it is preferable that the roller 423A arranged on the downstream side in the belt traveling direction with respect to the primary transfer roller 422 for the K component is the drive roller. This makes it easier to keep the running speed of the belt in the primary transfer unit constant. As the roller 423A rotates, the intermediate transfer belt 421 travels at a constant speed in the arrow A direction (one direction). The configuration of the belt cleaning device 426 will be described later.

The fixing portion 60 includes an upper fixing portion 60A having a fixing surface side member arranged on the fixing surface (the surface on which the toner image is formed) side of the paper S and the back surface (opposite surface of the fixing surface) side of the paper S. It has a lower fixing portion 60B having a back surface side support member arranged in, and a heating source 60C. By pressing the back surface side support member against the fixing surface side member, a fixing nip that narrowly holds and conveys the paper S is formed.

The fixing unit 60 fixes the toner image on the paper S by secondarily transferring the toner image and heating and pressurizing the conveyed paper S with the fixing nip. The fixing unit 60 is arranged as a unit in the fixing device F. Further, the fuser F may be provided with an air separation unit that separates the paper S from the fixing surface side member or the back surface side support member by blowing air.

The paper transport unit 50 includes a paper feed unit 51, a paper discharge unit 52, and a transport path unit 53. The three paper feed tray units 51a to 51c constituting the paper feed unit 51 accommodate the paper S (standard paper, special paper) identified based on the basis weight, size, etc. for each preset type. .. The transport path portion 53 has a plurality of transport roller pairs such as a resist roller pair 53a.

The paper S housed in the paper feed tray units 51a to 51c is sent out one by one from the uppermost portion, and is conveyed to the image forming unit 40 by the transfer path unit 53. At this time, the resist roller portion in which the resist roller pair 53a is arranged corrects the inclination of the fed paper S and adjusts the transfer timing. Then, in the image forming unit 40, the toner image of the intermediate transfer belt 421 is collectively secondarily transferred to one surface of the paper S, and the fixing step is performed in the fixing unit 60. The image-formed paper S is discharged to the outside of the machine by the paper ejection unit 52 provided with the paper ejection roller 52a.

The toner adhesion amount detection unit 73 faces the intermediate transfer belt 421 and detects the toner adhesion amount on the intermediate transfer belt 421. For the toner adhesion amount detection unit 73, for example, an IDC (Image Density Control) sensor, a CCD (Charge Coupled Device) image sensor, or the like is used. For example, the toner adhesion amount detection unit 73 has an optical sensor including a light emitting element and a light receiving element. The intermediate transfer belt 421 reflects light having an intensity corresponding to the amount of toner adhering to the intermediate transfer belt 421. For example, the smaller the amount of toner adhered to the intermediate transfer belt 421, the stronger the light is reflected by the intermediate transfer belt 421. The toner adhesion amount detection unit 73 detects the toner adhesion amount on the intermediate transfer belt 421 based on the reflection intensity (for example, voltage value) of the reflected light received by the light receiving element. The higher the reflection intensity of the reflected light received by the light receiving element, the smaller the toner adhesion amount detected by the toner adhesion amount detection unit 73.

The control unit 100 controls a transfer operation (for example, transfer bias) in the image forming unit 40 based on the detection result (toner adhesion amount) of the toner adhesion amount detection unit 73.

Here, the belt cleaning device 426 will be described in detail. FIG. 3 is a schematic view showing the configuration of the belt cleaning device 426. In FIG. 3, the intermediate transfer belt 421 and each photoconductor drum 413 are also shown. FIG. 4 is a cross-sectional view showing the configuration of the intermediate transfer belt 421. The plurality of irregularities on the surface of the coat layer 421b are not shown because they are fine.

As shown in FIG. 3, the belt cleaning device 426 has a first cleaning member 426a and a second cleaning member 426b, and removes the toner remaining on the intermediate transfer belt 421.

As shown in FIG. 4, the intermediate transfer belt 421 has a base material layer 421a and a coat layer 421b arranged on the base material layer 421a.

The base material layer 421a supports the coat layer 421b. The material of the base material layer 421a is not particularly limited as long as it can exhibit the above functions. Examples of the material of the base material layer 421a include a synthetic resin in which a conductive material such as polyimide (PI), polyamideimide, polyphenylene sulfide, or polyamide is dispersed. The base material layer 421a may be a single layer or a plurality of layers.

The coat layer 421b is arranged on the surface of the base material layer 421a. A plurality of irregularities are formed on the surface of the coat layer 421b opposite to the base material layer 421a. The material of the coat layer 421b _{is preferably a material containing silicon dioxide (SiO 2} ) as a main component. Examples of the material of the coat layer 421b include siloxane compounds (organic components) such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, and methyltriethoxysilane as silicon dioxide containing an alkyl group. As the material of the coat layer 421b, one type may be used alone, or two or more types may be used in combination.

_{The ten-point average roughness Rz jin} specified in JIS B 0601-2001 of the coat layer 421b is preferably 0.4 to 2.0 μm. When the ten-point average roughness Rz _{jin of the} coat layer 421b is 0.4 to 2.0 μm, interference between incident light and reflected light can be prevented.

The method for measuring the ten-point average roughness Rz _jin is not particularly limited as long as it complies with JIS B 0601-2001. The ten-point average roughness Rz _jin can be measured by a surface roughness measuring instrument (Surfcorder SE3500; Kosaka Seisakusho Co., Ltd.). The measurement conditions for the ten-point average roughness Rz are, for example, a feed rate of 0.2 mm / sec, a trace length of 12.5 mm, a cutoff value of λc of 2.5 mm, and an evaluation length of cutoff value × 5.

Further, the method of imparting roughness to the surface of the coat layer 421b (method of forming irregularities) is not particularly limited as long as the above-mentioned surface roughness can be imparted (concave and convex is formed). Examples of methods for forming the coat layer 421b include a dip coating method, a spray method, and an atmospheric pressure plasma CVD (Chemical Vapor Deposition) method. Further, as a method of imparting roughness to the coat layer 421b (forming unevenness), a method of forming the coat layer 421b by any of the above-mentioned methods using a coating agent in which predetermined particles are mixed, a method of forming the coat layer 421b, the coat layer 421b. After forming, a method of imparting a desired roughness by polishing the surface is included. Further, depending on the manufacturing method of the coat layer 421b, roughness can be imparted only by changing the manufacturing conditions.

The resistance (surface resistivity) of the base material layer 421a is preferably 9.0 to 12.0 LogΩ / □, for example. Further, the resistance of the coat layer 421b is preferably 0.5 to 2.0 LogΩ / □ higher than the resistance of the base material layer 421a. Further, the resistance of the intermediate transfer belt 421 in the state where the base material layer 421a and the coat layer 421b are laminated is preferably 9.1 to 12.1 LogΩ / □, more preferably 9.5 to 11.0 LogΩ / □. The resistance of the intermediate transfer belt 421 described above was determined by applying a voltage of 500 V with the insulating plate facing each other using a resistivity measuring device (High Resta UP; Mitsubishi Chemical Analytech Co., Ltd.). Further, the resistance of the intermediate transfer belt 421 alone was determined by making the facing plate conductive.

The first cleaning member 426a is formed in a plate shape and is arranged on the upstream side in the moving direction of the intermediate transfer belt 421. Here, the "plate shape" means a shape that makes line contact with the first cleaning member 426a. Therefore, the shape of the first cleaning member 426a may be a rectangular parallelepiped or a cube. One side of the first cleaning member 426a is applied to the intermediate transfer belt 421. At this time, the toner on the intermediate transfer belt 421 is removed by moving the intermediate transfer belt 421 in one direction. The direction of the line in which the first cleaning member 426a and the intermediate transfer belt 421 are in line contact with each other intersects the line along the moving direction of the intermediate transfer belt 421 (orthogonal in the present embodiment). The first cleaning member 426a is deformed when it comes into contact with the surface of the intermediate transfer belt 421 on which a plurality of irregularities are formed. That is, the hardness of the surface of the first cleaning member 426a is lower than the hardness of the surface of the intermediate transfer belt 421. The indentation hardness measured by the nanoindentation method on the surface of the first cleaning member 426a is, for example, 0.1 to 10 [MPa].

The material of the first cleaning member 426a is not particularly limited as long as the above requirements are satisfied. Examples of the material of the first cleaning member 426a include resin materials such as rubber and plastic, and other polymer materials. The material of the first cleaning member 426a is preferably rubber, and the material of the first cleaning member 426a is preferably a rubber blade.

The pressing force of the first cleaning member 426a on the intermediate transfer belt 421 is not particularly limited as long as the residual toner on the intermediate transfer belt 421 can be removed. The pressing force of the first cleaning member 426a on the intermediate transfer belt 421 is, for example, 10 to 50 [N / m].

The second cleaning member 426b is arranged on the downstream side in the moving direction of the intermediate transfer belt 421 with respect to the first cleaning member 426a. The second cleaning member 426b comes into contact with the surface of the intermediate transfer belt 421 on which a plurality of irregularities are formed. One side of the second cleaning member 426b is applied to the intermediate transfer belt 421. At this time, the toner on the intermediate transfer belt 421 is removed by moving the intermediate transfer belt 421 in one direction. In the present embodiment, the second cleaning member 426b has a metal plate 427 and a coating layer 428 formed on at least a part of the metal plate 427 (see FIG. 5). The second cleaning member 426b does not substantially deform even when it comes into contact with the intermediate transfer belt 421. That is, the hardness of the surface of the second cleaning member 426b is higher than the hardness of the surface of the intermediate transfer belt 421. The indentation hardness measured by the nanoindentation method on the surface of the second cleaning member 426b is, for example, 3.0 to 18.0 [GPa]. The hardness (indentation hardness) value of the second cleaning member 426b measured by the nanoindentation method is 8 to 40 times higher than the hardness (indentation hardness) value of the intermediate transfer belt 421 measured by the nanoindentation method. It is preferably the value of. If the hardness value measured by the nanoindentation method of the second cleaning member 426b is more than 40 times the hardness value measured by the nanoindentation method of the intermediate transfer belt 421, the intermediate transfer belt 421 may be damaged. On the other hand, if the value is less than 8 times, the toner remaining on the intermediate transfer belt 421 may not be properly removed.

The pressing force of the second cleaning member 426b on the intermediate transfer belt 421 is not particularly limited as long as the residual toner on the intermediate transfer belt 421 that could not be removed by the first cleaning member 426a can be removed. The pressing force of the second cleaning member 426b on the intermediate transfer belt 421 is, for example, 1 to 5 [N / m].

Further, comparing the pressing force of the first cleaning member 426a on the intermediate transfer belt 421 and the pressing force of the second cleaning member 426b on the intermediate transfer belt 421, the pressing force of the second cleaning member 426b on the intermediate transfer belt 421 is It is preferably weaker than the pressing force of the first cleaning member 426a on the intermediate transfer belt 421. This is because the second cleaning member 426b is harder than the first cleaning member 426a, so that the residual toner can be appropriately removed even if the pressing force on the intermediate transfer belt 421 is low. It is also for reducing damage to the intermediate transfer belt 421.

In the cross section along the moving direction of the intermediate transfer belt 421, the portion of the second cleaning member 426b that contacts the intermediate transfer belt 421 is formed in an arc shape. The arcuate radius R is preferably formed so as to enter a recess between two adjacent protrusions on the surface of the intermediate transfer belt 421. The arcuate radius R in contact with the intermediate transfer belt 421 of the second cleaning member 426b is less than half the average distance Sm of the distance between two adjacent convex portions on the surface of the intermediate transfer belt 421. More preferred. The Sm is preferably in the range of 100 to 400 μm. When the radius R satisfies the above condition, the arc shape can enter between two adjacent protrusions (recesses) on the surface of the intermediate transfer belt 421 and can be removed so as to scrape out the toner.

The average distance Sm of the distance between two adjacent convex portions on the surface of the intermediate transfer belt 421 can be measured by, for example, the following method. The average distance Sm of the distance between two adjacent convex portions on the surface of the intermediate transfer belt 421 can be measured using a surface roughness measuring instrument (Surfcorder SE3500; Kosaka Seisakusho Co., Ltd.). The measurement conditions for Sm are, for example, a feed rate of 0.2 mm / sec, a trace length of 12.5 mm, a cutoff value of λc of 2.5 mm, and an evaluation length of cutoff value × 5.

The arcuate shape may be arcuate at the corners of the metal plate, or may be arcuate due to the covering layer 428. 5A to 5C are schematic views showing an example of an arcuate configuration.

As shown in FIG. 5A, the arcuate shape may be such that the corners of the metal plate 427 and the corners of the coating layer 428 are arcuate, or as shown in FIG. 5B, only the corners of the coating layer 428 are arcuate. Good. In FIGS. 5A and 5B, the two sides adjacent to each other in an arc shape are formed so as to be vertical, but as shown in FIG. 5C, the two sides may be formed so as to have an acute angle.

The metal plate 427 supports the coating layer 428. Examples of the material of the metal plate 427 include stainless steel such as SUS304, titanium, and aluminum. The metal plate 427 is preferably stainless steel from the viewpoint of hardness and adhesion to the coating layer 428.

The coating layer 428 is formed on at least a part of the metal plate 427. Specifically, the coating layer 428 may be formed in a part of the region in contact with the intermediate transfer belt 421.

The material of the coating layer 428 is not particularly limited as long as the toner that cannot be completely removed by the first cleaning member 426a can be removed. Examples of the coating layer 428 include diamond-like carbon, hard chrome plating, ceramic coating, and Kashima coat. The material of the coating layer 428 is preferably diamond-like carbon from the viewpoint of hardness and adhesiveness to the metal plate 427.

The film thickness of the coating layer 428 is not particularly limited. The thickness of the coating layer 428 is preferably 0.1 to 10 μm.

The reason why the belt cleaning device 426 and the image forming device 1 according to the present embodiment function properly is presumed as follows. Here, a case where the toner remaining on the intermediate transfer belt 421 is removed will be described. In the belt cleaning device 426 and the image forming device 1 according to the present embodiment, first, one side of the elastic first cleaning member 426a is in line contact with the intermediate transfer belt 421 having a plurality of irregularities. At this time, the contact area between the surface of the intermediate transfer belt 421 and the first cleaning member 426a is reduced, and the contact portion of the first cleaning member 426a with the intermediate transfer belt 421 is not excessively deformed (pulling does not occur). Further, the first cleaning member 426a is deformed so as to bend, and most of the toner is removed from the intermediate transfer belt 421. Therefore, since the first cleaning member 426a does not wear, a large amount of toner can be stably removed during the period of use. However, since the first cleaning member has elasticity, toner easily enters the unevenness of the intermediate transfer belt 421 and may slip through the first cleaning member 426a. When the first cleaning member 426a having a hardness equal to or lower than the above-mentioned predetermined hardness is used, the contact portion of the first cleaning member 426a follows the unevenness of the surface of the intermediate transfer belt 42, excessive pulling occurs, and the first cleaning member 426a is worn. Resulting in. Therefore, in the present embodiment, the first cleaning member 426a having a predetermined hardness is used.

Next, with respect to the intermediate transfer belt 421 having a plurality of irregularities, a second having a tip shape that enters a recess between two adjacent convex portions of the intermediate transfer belt 421 in a cross section along the moving direction of the intermediate transfer belt 421. The cleaning member 426b comes into line contact. At this time, since the tip portion of the second cleaning member 426b enters the concave portion between the two adjacent convex portions on the surface of the intermediate transfer belt 421, stress is concentrated at the contact point with respect to the intermediate transfer belt 421, and the toner in the concave portion is scraped out. Power rises. Therefore, even when the toner is caught in the recess, the toner can be appropriately removed.

(effect)
As described above, according to the present invention, the first cleaning member having elasticity and the two adjacent intermediate transfer belts in the cross section along the moving direction of the intermediate transfer belt 421 with respect to the intermediate transfer belt having irregularities. Since it has a second cleaning member having a tip shape that penetrates into the concave portion between the protrusions, the toner can be substantially removed by the first cleaning member, and the toner that cannot be completely removed by the first cleaning member can be removed by the second cleaning member. ..

In the present embodiment, the intermediate transfer belt 421 in the image forming apparatus 1 has been described as an example of the member to be cleaned, but the member to be cleaned is not limited to the intermediate transfer belt. The member to be cleaned may be, for example, the photoconductor drum 413, a secondary transfer member, or a charging member.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples. In the example, the relationship between the arcuate radius R of the second cleaning member and the average distance Sm of the distance between two adjacent convex portions on the surface of the intermediate transfer belt was investigated with respect to the cleanability.

(Preparation of intermediate transfer belt)
A polyimide belt having a thickness of 70 μm was prepared as a base material layer for the intermediate transfer belt. Next, a coating agent for forming a coating layer was prepared. The coating agent contains 20 masses of organic components in the coat layer by adjusting the mass of both tetraalkoxysilane (Si (OR) ₄ ) and methyltrimethoxysilane ((CH ₃ ) ₃ SiCH _3). It was prepared to be%. The reason why the coat layer contains an organic component is to prevent cracks that occur when the component of the coat layer is only silicon dioxide and cannot follow the fluctuation of the intermediate transfer belt stretched on the roller. is there. Next, a coating agent was applied to the surface of the base material layer to form a coating layer.

The average value of the thickness of the coat layer measured as the average value of 12 points in the axial direction of the belt was 1.5 μm. The surface roughness of the coat layer was measured as an average value of 12 points in the circumferential direction of the intermediate transfer belt using a surface roughness measuring instrument (Surfcorder SE3500; Kosaka Seisakusho Co., Ltd.) under the above-mentioned conditions. The average value of the measured surface roughness was 0.75 μm. The hardness of the intermediate transfer belt is measured in the circumferential direction of the intermediate transfer belt by the nanoindentation method using an ultra-small indentation hardness tester (indenter shape; Berkovich, maximum load; 200 μN) (ENT-1100; Elionix Inc.). It was measured as an average value of 6 points. The average hardness of the intermediate transfer belt was 0.70 GPa. The average distance Sm of the distance between two adjacent protrusions on the surface of the intermediate transfer belt was 235 μm as measured under the above-mentioned conditions.

(Preparation of the first cleaning member)
As the first cleaning member, a urethane rubber blade having a hardness of 0.1 to 10 [MPa] by the nanoindentation method was prepared. The contact angle of the first cleaning member with respect to the intermediate transfer belt is 20 °. Here, the "contact angle" means a smaller angle among the angles formed by the virtual surface of the intermediate transfer belt and the first cleaning member in the cross section along the moving direction of the intermediate transfer belt.

(Preparation of the second cleaning member)
A metal scraper was prepared as the second cleaning member. Specifically, SUS304 was prepared as a metal plate. A diamond-like carbon paint was applied to the edge portion in contact with the intermediate transfer belt to form a surface layer. The contact angle of the second cleaning member with respect to the intermediate transfer belt is 16 °. The shape of the second cleaning member is SUS304 for the metal plate and diamond-like carbon paint for the surface layer. Further, a second cleaning member having an arcuate radius R of 156, 135, 112, 76, 54, 20, and 7 μm was prepared, respectively.

(Preparation of image forming device)
A modified full-color printing machine (AccurioPress C3080; Konica Minolta Co., Ltd.) equipped with the above-mentioned intermediate transfer belt, first cleaning member, and second cleaning member was prepared as an image forming apparatus. The main parameters of the image forming apparatus are shown in Table 1 below.

(Evaluation of cleanability)
For the evaluation of cleanability, the toner adhesion amount on the intermediate transfer belt was set to 8.0 g / m ² using the above-mentioned modified machine equipped with each cleaning device, and 10 sheets of toner images were sent to an A3 size recording medium. , The presence or absence of toner remaining on the intermediate transfer belt was visually confirmed. The cleanability was evaluated 5 times for each cleaning device. The evaluation criteria are as follows.
○; No toner slip-through △; Tolerable slight toner slip-through ×; Unacceptable toner slip-through Also, if it is judged to be suitable even once out of the five evaluations (evaluation criteria are ○ or △) Judged as conforming.

Table 2 shows the arc-shaped radius R, the average distance Sm ratio of the distances between two adjacent convex portions on the surface of the intermediate transfer belt, and the evaluation results.

As shown in Table 2, the cleaning devices 23 to 27 having an arcuate R (radius) of less than half of Sm had good cleanability. It is considered that this is because the arc shape enters between two adjacent convex portions (concave portions) and scrapes out the toner. Further, it is considered that the surface of the actual intermediate transfer belt is irregularly formed in both the axial direction and the circumferential direction of the intermediate transfer belt. Further, it is considered that the arcuate shape of the second cleaning member actually has a slightly uneven shape and is microscopically deformed. Therefore, even if it is macroscopically formed in a plate shape, it is considered that the cleaning property is good because the arc shape enters the recess.

In the embodiment, the length of the arcuate R was adjusted, but the same result could be obtained by adjusting the length of Sm (no particular result is shown). Therefore, at least one of R and Sm may be adjusted according to the convenience of the design of the cleaning device.

According to the present invention, for example, the residual toner on the intermediate transfer belt can be appropriately removed. Therefore, according to the present invention, further improvement in quality of the formed image is expected.

1 Image forming device 10 Image reading unit 11 Automatic document feeding device 12 Original document scanning device 12a CCD sensor 20 Operation display unit 21 Display unit 22 Operation unit 30 Image processing unit 40 Image forming unit 41, 41C, 41K, 41M, 41Y Image Forming unit 42 Intermediate transfer unit 50 Paper transport unit 51 Paper feed section 51a, 51b, 51c Paper feed tray unit 52 Paper discharge section 52a Paper discharge roller 53 Transport path section 53a Resist roller vs. 60 Fixing section 60A Upper fixing section 60B Lower fixing Unit 60C Heating source 71 Communication unit 72 Storage unit 73 Toner adhesion amount detection unit 100 Control unit 101 CPU
102 ROM
103 RAM
411 Exposure device 412 Developing device 413 Photoreceptor drum 414 Charging device 415 Drum cleaning device 421 Intermediate transfer belt 421a Base material layer 421b Coat layer 422 Primary transfer roller 423 Support roller 423A Roller 423B Backup roller 424 Secondary transfer roller 426 Belt cleaning device Cleaning device)
426a 1st cleaning member 426b 2nd cleaning member 427 Metal plate 428 Coating layer D Manuscript F Fixer S Paper

Claims (8)

A cleaning device for cleaning a member to be cleaned that has a plurality of irregularities formed on the surface and moves in one direction.
A plate-shaped first cleaning member configured to be in contact with the surface of the member to be cleaned and having elasticity.
It has a second cleaning member that is arranged downstream of the first cleaning member in the moving direction of the member to be cleaned and is configured to come into contact with the surface of the member to be cleaned.
In the cross section along the moving direction of the member to be cleaned, the tip shape of the second member to be cleaned is a shape that fits into a recess between two adjacent protrusions of the member to be cleaned.
Cleaning device. The second cleaning member is formed in a plate shape and has a plate shape.
The hardness of the surface of the second cleaning member is higher than the hardness of the surface of the first cleaning member.
The cleaning device according to claim 1. In the cross section along the moving direction of the member to be cleaned, the shape of the portion of the second member to be cleaned that is configured to be in contact with the surface of the member to be cleaned is arcuate.
In the cross section along the moving direction of the member to be cleaned, the arcuate radius R is less than half the average distance Sm of the distance between two adjacent convex portions on the surface of the member to be cleaned.
The cleaning device according to claim 1 or 2. The first cleaning member is a rubber blade.
The second cleaning member comprises a metal plate and a diamond-like carbon coating layer arranged on a portion of the surface of the metal plate that is configured to be in contact with at least the surface of the member to be cleaned. Scraper to have,
The cleaning device according to any one of claims 1 to 3. The cleaning device according to any one of claims 1 to 4, wherein the pressing force of the second cleaning member on the member to be cleaned is weaker than the pressing force of the first cleaning member on the member to be cleaned. It is an electrophotographic image forming apparatus.
A member to be cleaned that has multiple irregularities formed on the surface and moves in one direction,
A plate-shaped first cleaning member that comes into contact with the surface of the member to be cleaned and has elasticity.
A second cleaning member that comes into contact with the surface of the member to be cleaned and is arranged on the downstream side in the moving direction of the member to be cleaned from the first cleaning member.
It is an image forming apparatus having
In the cross section along the moving direction of the member to be cleaned, the tip shape of the second member to be cleaned is a shape that fits into a concave portion between two adjacent convex portions of the member to be cleaned.
The member to be cleaned is an image carrier on which a toner image is supported.
Image forming device. The image carrier is
Base layer and
A coat layer containing silicon dioxide as a main component, which is arranged on the surface of the base material layer,
Have,
The image forming apparatus according to claim 6. The image forming apparatus according to claim 6 or 7, wherein the ten-point average roughness Rz _{jis on the surface of the image carrier is 0.4 to 2.0 μm.}

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