JP7342570B2 - Cleaning device and image forming device - Google Patents

Description

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

Generally, electrophotographic image forming devices (printers, copiers, facsimile machines, etc.) form electrostatic latent images by irradiating (exposure) a charged photoreceptor with laser light 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, the toner image is transferred to a recording medium via an intermediate transfer body, and then heated and pressurized to fix it, thereby forming an image on the recording medium.

In such an image forming apparatus, toner remaining on the photoreceptor or intermediate transfer member (member to be cleaned) is removed by a cleaning device (for example, see 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 disposed on the upstream side in the moving direction of the member to be cleaned, and a non-deformable cleaning member disposed on the downstream side in the moving direction of the member to be cleaned. In the cleaning device described in Patent Document 1, after roughly removing toner using an elastic cleaning member, a non-deformable cleaning member removes toner that could not be completely removed by the elastic cleaning member.

Further, in the above-described image forming apparatus, a sensor optically detects the amount of toner remaining on the surface of the member to be cleaned. In this case, the incident light and reflected light emitted from the light emitting side of the sensor interfere with each other, resulting in noise on the light receiving side of the sensor, making it impossible to accurately measure the amount of residual toner attached. In contrast, an intermediate transfer body that prevents interference between incident light and reflected light is known (for example, see 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 made within a predetermined range to scatter light and prevent interference between incident light and reflected light.

Japanese Patent Application Publication No. 2002-278319 JP2017-245260A

Here, it is possible to remove the residual toner on the intermediate transfer member described in Patent Document 2 using the cleaning device described in Patent Document 1. However, Patent Document 1 does not describe an intermediate transfer body as described in Patent Document 2, and Patent Document 2 does not describe a cleaning device as described in Patent Document 1. However, there is still room for consideration in how to appropriately remove toner remaining on the intermediate transfer member. 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 this will decrease.

An object of the present invention is to provide a cleaning device and an image forming apparatus that can appropriately remove foreign matter remaining on a member to be cleaned.

A cleaning device as one means for solving the above problems is a cleaning device for cleaning a member to be cleaned that has a plurality of unevenness formed on the surface and moves in one direction, and is a cleaning device for cleaning a member to be cleaned that moves in one direction. a first cleaning member configured to be in contact with the surface and having an elastic plate shape; and a first cleaning member disposed downstream of the first cleaning member in the moving direction of the member to be cleaned, and contacting the surface of the member to be cleaned. a second cleaning member configured to be in contact with each other, and in a cross section along the moving direction of the member to be cleaned, the tip end shape of the second cleaning member is configured to be in contact with two adjacent convex portions of the member to be cleaned. It has a shape that fits into the recess between the two.

An image forming apparatus as one means for solving the above problems is an electrophotographic image forming apparatus, which includes a member to be cleaned that has a plurality of unevenness formed on its surface and moves in one direction, and a member to be cleaned that moves in one direction. a first elastic plate-shaped cleaning member that contacts the surface of the cleaning member; and a first cleaning member that contacts the surface of the member to be cleaned and is located downstream of the first cleaning member in the direction of movement of the member to be cleaned. an image forming apparatus comprising: a second cleaning member, in which, in a cross section along the moving direction of the member to be cleaned, a tip end shape of the second cleaning member is shaped like 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 apparatus that can appropriately remove foreign matter remaining on a member to be cleaned.

FIG. 1 is a diagram showing the configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing main parts of a control system of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram showing the configuration of a cleaning device according to an embodiment of the present invention. FIG. 4 is a sectional view showing the structure of the intermediate transfer belt. FIGS. 5A to 5C are schematic diagrams showing examples of arcuate configurations.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A cleaning device according to an embodiment of the present invention and an image forming apparatus including the cleaning device will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a diagram showing the configuration of an image forming apparatus 1 according to an embodiment of the present invention. FIG. 2 is a diagram showing the main parts of the control system of the image forming apparatus 1 according to an 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 using electrophotographic process technology. That is, the image forming apparatus 1 transfers toner images of each color of Y (yellow), M (magenta), C (cyan), and K (black) formed on the photoreceptor drum 413 to an intermediate transfer belt (intermediate transfer body) 421. An image is formed by firstly transferring the toner image to a (member to be cleaned), overlapping the four-color toner images on the intermediate transfer belt 421, and then secondarily transferring it to the paper S (recording medium). Note that the image forming apparatus 1 may be an apparatus that forms a monochromatic image (for example, a monochrome image).

The image forming apparatus 1 uses a tandem system in which photosensitive drums 413 corresponding to four colors of YMCK are arranged in series in the running direction of an intermediate transfer belt 421, and toner images of each color are sequentially transferred to the intermediate transfer belt 421 in one step. has been adopted.

The image forming apparatus 1 includes an image reading section 10 , an operation display section 20 , an image processing section 30 , an image forming section 40 , a paper transport section 50 , a fixing section 60 , and a control section 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, loads it into the RAM 103, and centrally controls the operation of each block of the image forming apparatus 1 in cooperation with the loaded program. At this time, various data stored in the storage section 72 are referred to. The storage unit 72 is, for example, a nonvolatile 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 a WAN (Wide Area Network) via the communication unit 71. conduct. The control unit 100 receives image data transmitted from, for example, an external device, and forms an image on the sheet S based on this image data (input image data). The communication unit 71 is, for example, 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 feeder 11 uses a conveyance mechanism to convey the document D placed on the document tray and sends it to the document image scanning device 12 . The automatic document feeder 11 can continuously read images (including both sides) of a large number of documents D placed on a document tray at one time.

The document image scanning device 12 optically scans the document conveyed onto the contact glass from the automatic document feeder 11 or the document placed on the contact glass, and converts the reflected light from the document into 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 reading result by the original image scanning device 12. This input image data is subjected to predetermined image processing in the image processing section 30.

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, image status display, operating status of each function, etc. in accordance with display control signals 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 from the user, and outputs operation signals to the control unit 100.

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

The image forming unit 40 includes image forming units 41Y, 41M, 41C, and 41K for forming images using colored toners of Y component, M component, C component, and K component based on input image data, and an intermediate transfer unit. 42.

Image forming units 41Y, 41M, 41C, and 41K for Y component, M component, C component, and K component have the same configuration. In the following description, for convenience of illustration and explanation, 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, only the constituent elements of the image forming unit 41Y for the Y component are labeled, and the constituent elements of the other image forming units 41M, 41C, and 41K are omitted.

The image forming unit 41 includes an exposure device 411 , a developing device 412 , a photosensitive 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 photosensitive drum 413 with laser light corresponding to an image of each color component. As a result, electrostatic latent images of each color component are formed on the surface of the photoreceptor drum 413 due to the potential difference with the surroundings.

The developing device 412 is, for example, a two-component reversal type developing device, and by attaching toner of each color component to the surface of the photoreceptor drum 413, the electrostatic latent image is visualized and a toner image is formed. The developing device 412 includes a developing sleeve arranged to face the photoreceptor drum 413 with a developing area interposed therebetween. For example, a DC developing bias having the same polarity as the charging polarity of the charging device 414 or a developing bias in which a DC voltage having the same polarity as the charging polarity of the charging device 414 is superimposed on an AC voltage is applied to the developing sleeve. As a result, reversal development is performed in which toner is attached to the electrostatic latent image formed by the exposure device 411.

The photoreceptor drum 413 is, for example, an organic photoreceptor in which a photosensitive layer made of resin containing an organic photoconductor is formed on the outer peripheral surface of a drum-shaped metal base.

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

The charging device 414 is, for example, a charging charger, and uniformly charges the surface of the photoconductive drum 413 to a negative polarity by generating corona discharge.

The drum cleaning device 415 is in contact with the surface of the photoreceptor drum 413 and includes a flat drum cleaning blade made of an elastic material, and remains on the surface of the photoreceptor drum 413 without being transferred to the intermediate transfer belt 421. Remove 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 that includes the intermediate transfer belt 421 .

The primary transfer roller 422 is arranged on the inner peripheral surface side of the intermediate transfer belt 421, facing the photosensitive drum 413 of each color component. By pressing the primary transfer roller 422 against the photoreceptor drum 413 with the intermediate transfer belt 421 in between, a primary transfer nip for transferring the toner image from the photoreceptor 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, facing the backup roller 423B, which is arranged downstream of the roller 423A in the belt running direction. By pressing the secondary transfer roller 424 against the backup roller 423B with the intermediate transfer belt 421 in between, 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 images on the photoreceptor drum 413 are primarily transferred onto the intermediate transfer belt 421 in a sequentially overlapping manner. Specifically, by applying a primary transfer bias to the primary transfer roller 422 and applying an electric charge of opposite polarity to the toner to the back side of the intermediate transfer belt 421 (the side that contacts the primary transfer roller 422), the toner image is transferred. The image is electrostatically transferred to the intermediate transfer belt 421.

Thereafter, 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, by applying a secondary transfer bias to the secondary transfer roller 424 and applying an electric charge of opposite polarity to the toner to the back side of the paper S (the side that contacts the secondary transfer roller 424), the toner image is transferred. is electrostatically transferred to the paper S. The paper S onto which the toner image has been transferred is conveyed toward the fixing section 60.

The belt cleaning device 426 removes transfer residual toner remaining on the surface of the intermediate transfer belt 421 after the secondary transfer. The intermediate transfer belt 421 is an endless belt, and is stretched around a plurality of support rollers 423 in a loop shape. At least one of the plurality of support rollers 423 is configured as a driving roller, and the others are configured as driven rollers. For example, it is preferable that a roller 423A disposed downstream of the primary transfer roller 422 for the K component in the belt running direction is a driving roller. This makes it easier to maintain a constant running speed of the belt in the primary transfer section. As the roller 423A rotates, the intermediate transfer belt 421 runs at a constant speed in the direction of arrow A (one direction). The configuration of the belt cleaning device 426 will be described later.

The fixing section 60 includes an upper fixing section 60A having a fixing surface side member disposed on the fixing surface side of the paper S (the surface on which the toner image is formed), and an upper fixing section 60A having a fixing surface side member disposed on the fixing surface side of the paper S (the surface opposite to the fixing surface). It has a lower fixing section 60B having a back side support member disposed at the bottom, and a heat source 60C. By pressing the back side support member against the fixing side member, a fixing nip is formed in which the sheet S is held and conveyed.

The fixing unit 60 fixes the toner image onto the paper S by heating and pressurizing the paper S to which the toner image has been secondarily transferred and is being conveyed using a fixing nip. The fixing section 60 is arranged within the fixing device F as a unit. Further, the fixing device F may be provided with an air separation unit that separates the paper S from the fixing side member or the back side supporting member by blowing air.

The paper transport section 50 includes a paper feed section 51 , a paper discharge section 52 , and a transport path section 53 . The three paper feed tray units 51a to 51c constituting the paper feed section 51 store sheets S (standard paper, special paper) that are identified based on basis weight, size, etc., according to preset types. . The conveyance path section 53 includes a plurality of conveyance roller pairs such as a registration roller pair 53a.

The sheets S stored in the paper feed tray units 51a to 51c are fed out one by one from the top and conveyed to the image forming section 40 by the conveyance path section 53. At this time, the inclination of the fed sheet S is corrected and the conveyance timing is adjusted by the registration roller section in which the registration roller pair 53a is disposed. Then, in the image forming section 40, the toner image on the intermediate transfer belt 421 is secondarily transferred all at once onto one side of the paper S, and then a fixing process is performed in the fixing section 60. The paper S on which the image has been formed is ejected to the outside of the machine by a paper ejection section 52 equipped with a paper ejection roller 52a.

The toner adhesion amount detection section 73 faces the intermediate transfer belt 421 and detects the amount of toner adhesion on the intermediate transfer belt 421 . For the toner adhesion amount detection section 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 section 73 includes an optical sensor including a light emitting element and a light receiving element. The intermediate transfer belt 421 reflects light with an intensity corresponding to the amount of toner attached 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 amount of toner adhesion detected by the toner adhesion amount detection section 73.

The control unit 100 controls the transfer operation (for example, transfer bias, etc.) 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 explained in detail. FIG. 3 is a schematic diagram showing the configuration of the belt cleaning device 426. In FIG. 3, the intermediate transfer belt 421 and each photosensitive drum 413 are also illustrated. FIG. 4 is a cross-sectional view showing the structure of the intermediate transfer belt 421. Note that the plurality of irregularities on the surface of the coat layer 421b are not shown because they are minute.

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

As shown in FIG. 4, the intermediate transfer belt 421 includes a base layer 421a and a coat layer 421b disposed on the base layer 421a.

The base 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 function. Examples of materials for the base layer 421a include synthetic resins in which conductive materials such as polyimide (PI), polyamideimide, polyphenylene sulfide, and polyamide are dispersed. The base material layer 421a may have a single layer or multiple layers.

Coat layer 421b is arranged on the surface of base material layer 421a. A plurality of projections and depressions are formed on the surface of the coat layer 421b opposite to the base 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 for the coat layer 421b include siloxane compounds (organic components) such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, and methyltriethoxysilane as silicon dioxide containing an alkyl group. One type of material for the coat layer 421b may be used alone, or two or more types may be used in combination.

The ten-point average roughness Rz _jin of the coating layer 421b specified in JIS B 0601-2001 is preferably 0.4 to 2.0 μm. If the ten-point average roughness Rz _jin of the coating 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 with a surface roughness measuring device (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 λc of 2.5 mm, and an evaluation length of cutoff value x 5.

Further, the method for imparting roughness to the surface of the coat layer 421b (method for forming irregularities) is not particularly limited as long as the above-mentioned surface roughness can be imparted (forming irregularities). 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, methods for imparting roughness to the coat layer 421b (forming unevenness) include a method of forming the coat layer 421b using any of the methods described above using a coating agent mixed with predetermined particles; This includes a method of imparting desired roughness by polishing the surface after formation. Furthermore, depending on the method of manufacturing the coat layer 421b, roughness can be imparted simply by changing the manufacturing conditions.

Further, 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 coating layer 421b is preferably 0.5 to 2.0 LogΩ/□ higher than the resistance of the base layer 421a. Further, the resistance of the intermediate transfer belt 421 in which the base layer 421a and the coating 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 using a resistivity measuring device (Hiresta UP; manufactured by Mitsubishi Chemical Analytech, Inc.) with an insulating plate facing the belt. Further, the resistance of the intermediate transfer belt 421 alone was determined by assuming that the opposing plate was conductive.

The first cleaning member 426a is formed into a plate shape and is disposed on the upstream side in the moving direction of the intermediate transfer belt 421. Here, "plate-like" 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. The first cleaning member 426a contacts the intermediate transfer belt 421 with one side thereof. At this time, by moving the intermediate transfer belt 421 in one direction, the toner on the intermediate transfer belt 421 is removed. The direction of the line where the first cleaning member 426a and the intermediate transfer belt 421 are in line contact intersects (orthogonally in this embodiment) the line along the moving direction of the intermediate transfer belt 421. The first cleaning member 426a deforms when it comes into contact with the surface of the intermediate transfer belt 421 on which a plurality of projections and depressions 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 of the surface of the first cleaning member 426a measured by a nanoindentation method is, for example, 0.1 to 10 [MPa].

The material of the first cleaning member 426a is not particularly limited as long as it satisfies the above requirements. Examples of the material of the first cleaning member 426a include rubber, resin materials such as plastics, and other polymeric materials. The material of the first cleaning member 426a is preferably rubber, and the first cleaning member 426a is preferably a rubber blade.

The pressing force applied by the first cleaning member 426a to the intermediate transfer belt 421 is not particularly limited as long as it can remove residual toner on the intermediate transfer belt 421. The pressing force exerted by 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 downstream of the first cleaning member 426a in the moving direction of the intermediate transfer belt 421. The second cleaning member 426b comes into contact with the surface of the intermediate transfer belt 421 on which a plurality of projections and depressions are formed. The second cleaning member 426b has one side in contact with the intermediate transfer belt 421. At this time, by moving the intermediate transfer belt 421 in one direction, the toner on the intermediate transfer belt 421 is removed. In this embodiment, the second cleaning member 426b includes a metal plate 427 and a coating layer 428 formed on at least a portion 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 of the surface of the second cleaning member 426b measured by the nanoindentation method is, for example, 3.0 to 18.0 [GPa]. Further, the hardness (indentation hardness) value of the second cleaning member 426b measured by the nanoindentation method is 8 to 40 times the hardness (indentation hardness) value measured by the nanoindentation method of the intermediate transfer belt 421. It is preferable that the value is . 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 applied by the second cleaning member 426b to the intermediate transfer belt 421 is not particularly limited as long as it can remove residual toner on the intermediate transfer belt 421 that could not be removed by the first cleaning member 426a. The pressing force exerted by the second cleaning member 426b on the intermediate transfer belt 421 is, for example, 1 to 5 [N/m].

Further, when comparing the pressing force of the first cleaning member 426a against the intermediate transfer belt 421 and the pressing force of the second cleaning member 426b against the intermediate transfer belt 421, the pressing force of the second cleaning member 426b against the intermediate transfer belt 421 is as follows. It is preferable that the pressing force be weaker than the pressing force applied to the intermediate transfer belt 421 by the first cleaning member 426a. This is because the second cleaning member 426b is harder than the first cleaning member 426a and can appropriately remove residual toner even if the pressing force against the intermediate transfer belt 421 is low. This is also to reduce damage to the intermediate transfer belt 421.

In a cross section along the moving direction of the intermediate transfer belt 421, a portion of the second cleaning member 426b that contacts the intermediate transfer belt 421 is formed in an arc shape. It is preferable that the radius R of the circular arc is formed so as to fit into a recess between two adjacent projections on the surface of the intermediate transfer belt 421. The radius R of the arc of the second cleaning member 426b that contacts the intermediate transfer belt 421 may be 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. Note that Sm is preferably within the range of 100 to 400 μm. When the radius R satisfies the above conditions, the arc shape enters between two adjacent convex portions (concave portions) on the surface of the intermediate transfer belt 421, and the toner can be scraped out and removed.

The average distance Sm between two adjacent convex portions on the surface of the intermediate transfer belt 421 can be measured, for example, by the following method. The average distance Sm between two adjacent convex portions on the surface of the intermediate transfer belt 421 can be measured using a surface roughness measuring device (Surfcorder SE3500; manufactured by 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 λc of 2.5 mm, and an evaluation length of cutoff value x 5.

The arc shape may be a corner of the metal plate, or may be formed by the coating layer 428. FIGS. 5A to 5C are schematic diagrams showing examples of arcuate configurations.

As shown in FIG. 5A, the corner of the metal plate 427 and the corner of the covering layer 428 may be arc-shaped, or as shown in FIG. 5B, only the corner of the covering layer 428 may be arc-shaped. good. In FIGS. 5A and 5B, the two sides adjacent to each other in the arc shape are formed to be perpendicular, but as shown in FIG. 5C, the two sides may be formed to form an acute angle.

Metal plate 427 supports covering layer 428. Examples of materials for the metal plate 427 include stainless steel such as SUS304, titanium, and aluminum. The metal plate 427 is preferably made of stainless steel from the viewpoint of hardness and adhesion with the coating layer 428.

The covering layer 428 is formed on at least a portion of the metal plate 427. Specifically, the covering layer 428 only needs to be formed in a part of the region that contacts the intermediate transfer belt 421.

The material of the covering layer 428 is not particularly limited as long as it can remove toner that could not be removed by the first cleaning member 426a. 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 with the metal plate 427.

The thickness of the covering 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 apparatus 1 according to this embodiment function properly is presumed to be as follows. Here, a case will be described in which toner remaining on the intermediate transfer belt 421 is removed. In the belt cleaning device 426 and the image forming apparatus 1 according to the present embodiment, first, one side of the first cleaning member 426a having elasticity comes into 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 becomes small, and the contact portion of the first cleaning member 426a with the intermediate transfer belt 421 is not excessively deformed (no dragging occurs). Further, the first cleaning member 426a is deformed so as to be bent, and most of the toner is removed from the intermediate transfer belt 421. Therefore, since the first cleaning member 426a does not wear out, 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. If the first cleaning member 426a whose hardness is less than the above-mentioned predetermined hardness is used, the contact portion of the first cleaning member 426a will follow the unevenness of the surface of the intermediate transfer belt 42, causing excessive dragging and causing the first cleaning member 426a to wear out. Resulting in. Therefore, in this 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 concave and convex portions, a second tip having a tip shape that fits into a concave portion 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 is formed. Cleaning member 426b makes line contact. At this time, since the tip of the second cleaning member 426b enters the recess between the two adjacent projections on the surface of the intermediate transfer belt 421, stress is concentrated at the point of contact with the intermediate transfer belt 421, scraping out the toner in the recess. Power increases. Therefore, even if toner is caught in the recess, the toner can be appropriately removed.

(effect)
As described above, according to the present invention, the elastic first cleaning member and the two adjacent intermediate transfer belts in the cross section along the moving direction of the intermediate transfer belt 421 can be cleaned with respect to the uneven intermediate transfer belt. Since the second cleaning member has a tip shape that fits into the recess between the convex parts, most of the toner can be removed by the first cleaning member, and the toner that cannot be removed by the first cleaning member can be removed by the second cleaning member. .

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

EXAMPLES Hereinafter, the present invention will be specifically explained using 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 with respect to cleaning performance was investigated.

(Preparation of intermediate transfer belt)
A polyimide belt having a thickness of 70 μm was prepared as the base material layer of the intermediate transfer belt. Next, a coating agent for forming a coating layer was prepared. The coating agent was prepared by adjusting the mass of both tetraalkoxysilane (Si(OR) ₄ ) and methyltrimethoxysilane ((CH ₃ ) ₃ SiCH ₃ ) so that the content of the organic component in the coating layer was 20% by mass. %. The purpose of containing an organic component in the coating layer is to prevent cracks from occurring due to the inability to follow the fluctuations of the intermediate transfer belt stretched over a roller when the coating layer contains only silicon dioxide. be. Next, a coating agent was applied to the surface of the base layer to form a coating layer.

The average value of the thickness of the coating layer, which was 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 the average value of 12 points in the circumferential direction of the intermediate transfer belt using a surface roughness measuring device (Surfcorder SE3500; Kosaka Seisakusho Co., Ltd.) under the conditions described above. The average value of the measured surface roughness was 0.75 μm. The hardness of the intermediate transfer belt was determined by the nanoindentation method using an ultra-fine indentation hardness tester (indenter shape: Berkovich, maximum load: 200 μN) (ENT-1100; Elionix Co., Ltd.) in the circumferential direction of the intermediate transfer belt. It was measured as the average value of 6 points. The average hardness of the intermediate transfer belt was 0.70 GPa. The average distance Sm between two adjacent convex portions on the surface of the intermediate transfer belt was 235 μm when measured under the conditions described above.

(Preparation of first cleaning member)
As the first cleaning member, a urethane rubber blade having a hardness of 0.1 to 10 [MPa] determined 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 the smaller angle among the angles formed between the virtual surface of the intermediate transfer belt and the first cleaning member in a cross section along the moving direction of the intermediate transfer belt.

(Preparation of second cleaning member)
A metal scraper was prepared as the second cleaning member. Specifically, SUS304 was prepared as the metal plate. A surface layer was formed by applying diamond-like carbon paint to the edge portion that would contact the intermediate transfer belt. The contact angle of the second cleaning member with respect to the intermediate transfer belt is 16°. The second cleaning member has a metal plate made of SUS304 and a surface layer made of diamond-like carbon paint. In addition, second cleaning members each having an arcuate radius R of 156, 135, 112, 76, 54, 20, and 7 μm were prepared.

(Preparation of image forming device)
A modified full-color printing machine (AccurioPress C3080; manufactured by Konica Minolta, Inc.) 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 cleaning performance)
The cleaning performance was evaluated by using the above-mentioned modified machine equipped with each cleaning device, setting the toner adhesion amount on the intermediate transfer belt to 8.0 g/ ^m2 , and sending toner images for 10 sheets onto an A3 size recording medium. The presence or absence of toner remaining on the intermediate transfer belt was visually confirmed. The cleaning performance was evaluated five times for each cleaning device. The evaluation criteria are as follows.
○: No toner slip-through △: Tolerable slight toner slip-through ×: Unacceptable toner slip-through In addition, if it is determined that compliance is met even once out of the 5 evaluations (evaluation criteria is ○ or △) was judged to be suitable.

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

As shown in Table 2, cleaning devices 23 to 27 in which the arcuate R (radius) was less than half of Sm had good cleaning performance. This is considered to be because the circular arc entered between two adjacent convex portions (concave portions) and scraped out the toner. Further, it is considered that the surface of the actual intermediate transfer belt is irregularly uneven in both the axial direction and the circumferential direction of the intermediate transfer belt. Further, the arcuate shape of the second cleaning member actually has some unevenness, and is considered to be microscopically deformed. Therefore, even if it is macroscopically formed into a plate shape, it is considered that the cleaning performance is good because the arc shape fits into the recess.

In the example, the length of the arc-shaped R was adjusted, but similar results could be obtained even if the length of Sm was adjusted (results in particular are not shown). Therefore, at least one of R and Sm may be adjusted depending on the design of the cleaning device.

According to the present invention, for example, residual toner on the intermediate transfer belt can be appropriately removed. Therefore, according to the present invention, it is expected that the quality of formed images will be further improved.

1 Image forming device 10 Image reading section 11 Automatic document feeder 12 Document image scanning device 12a CCD sensor 20 Operation display section 21 Display section 22 Operation section 30 Image processing section 40 Image forming section 41, 41C, 41K, 41M, 41Y Image Forming unit 42 Intermediate transfer unit 50 Paper transport section 51 Paper feed section 51a, 51b, 51c Paper feed tray unit 52 Paper discharge section 52a Paper discharge roller 53 Conveyance path section 53a Registration roller pair 60 Fixing section 60A Upper fixing section 60B Lower fixing Section 60C Heat source 71 Communication section 72 Storage section 73 Toner adhesion amount detection section 100 Control section 101 CPU
102 ROM
103 RAM
411 Exposure device 412 Developing device 413 Photosensitive drum 414 Charging device 415 Drum cleaning device 421 Intermediate transfer belt 421a Base material layer 421b Coating layer 422 Primary transfer roller 423 Support roller 423A Roller 423B Backup roller 424 Secondary transfer roller 426 Belt cleaning device ( cleaning device)
426a First cleaning member 426b Second cleaning member 427 Metal plate 428 Covering layer D Original F Fixing device S Paper

Claims (7)

A cleaning device for cleaning a member to be cleaned that has a plurality of irregularities formed on its surface and moves in one direction,
a first elastic plate-shaped cleaning member configured to contact the surface of the member to be cleaned;
a second cleaning member arranged downstream of the first cleaning member in the moving direction of the member to be cleaned and configured to contact the surface of the member to be cleaned;
In a cross section along the moving direction of the member to be cleaned, the tip of the second cleaning member has a shape that fits into a recess between two adjacent protrusions of the member to be cleaned, and The shape of the portion configured to contact the surface of the member to be cleaned is an arcuate shape,
In a cross section along the moving direction of the member to be cleaned, the radius R of the circular arc 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.
cleaning equipment. The second cleaning member is formed in 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. The first cleaning member is a rubber blade,
The second cleaning member includes a metal plate and a coating layer made of diamond-like carbon disposed on a surface of the metal plate that is configured to contact at least the surface of the member to be cleaned. is a scraper with
The cleaning device according to claim 1 or claim 2 . The cleaning device according to any one of claims 1 to 3 , wherein the pressing force of the second cleaning member against the member to be cleaned is weaker than the pressing force of the first cleaning member against the member to be cleaned. a member to be cleaned having a plurality of irregularities formed on its surface and moving in one direction;
a plate-shaped first cleaning member that is in contact with the surface of the member to be cleaned and has elasticity;
a second cleaning member that is in contact with the surface of the member to be cleaned and is disposed downstream of the first cleaning member in the moving direction of the member to be cleaned;
An electrophotographic image forming apparatus having:
In a cross section along the moving direction of the member to be cleaned, the tip of the second cleaning member has a shape that fits into a recess between two adjacent protrusions of the member to be cleaned, and The shape of the portion configured to contact the surface of the member to be cleaned is an arcuate shape,
In a cross section along the moving direction of the member to be cleaned, the radius R of the circular arc 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 member to be cleaned is an image carrier on which a toner image is carried.
Image forming device. The image carrier is
a base material layer;
a coat layer mainly composed of silicon dioxide disposed on the surface of the base layer;
has,
The image forming apparatus according to claim 5 . The image forming apparatus according to claim 5 or 6 , wherein a ten-point average roughness Rz _jis on the surface of the image carrier is 0.4 to 2.0 μm.

Images