JP2015230432A - Cleaning device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device that can suppress the occurrence of leak discharge between the rotation shaft of a cleaning member and a support member while achieving a reduction in size of the device, and an image forming apparatus.SOLUTION: There is provided a cleaning device 100 including a cleaning member 102 that is provided rotatably on the rotation shaft to remove a toner on a cleaning target object 8, voltage application means for applying a voltage to the rotation shaft 250 of the cleaning member, and support members 310 that support the rotation shaft, where the support members each comprise a non-conductive bearing part 310 that supports the rotation shaft and a metallic bearing support part 330 that supports the bearing part, and when the creepage distance that is the shortest distance along the surface of the support member from a contact position of the rotation shaft and the bearing part to the bearing support part is X[mm], and a voltage to be applied to the rotation shaft by the voltage application means is Y[kV], the relationship X[mm]≥Y[kV]×2[mm/kV] is satisfied.

Description

  The present invention relates to a cleaning device used in an image forming apparatus such as a printer, a facsimile machine, and a copying machine, and an image forming apparatus provided with the cleaning device.

  Conventionally, image forming apparatuses are provided with a plurality of toner image forming portions for forming toner images of different colors in order to cope with high speed, and these are arranged in a straight line in the direction of surface movement of the intermediate transfer belt. A tandem color image forming apparatus is known.

  In this tandem type color image forming apparatus, for each toner image forming unit, latent images of images corresponding to different colors formed individually on the respective photoreceptors are individually converted into toner images by a developing device. Then, the toner images of different colors formed for the respective photoconductors are transferred while being sequentially superimposed on the intermediate transfer belt, and then the toner image is transferred from the intermediate transfer belt onto the recording paper as the transfer material, so that the color image is formed on the recording paper. Is what you get.

  Further, as an intermediate transfer belt cleaning device that removes transfer residual toner on the intermediate transfer belt in such an image forming apparatus, an electrostatic cleaning type cleaning device that removes toner using an electrostatic force is adopted. It has been known.

  The cleaning device of the electrostatic cleaning system described in Patent Document 1 is provided with a cleaning brush roller that rotates around a rotation shaft while being in contact with an intermediate transfer belt that is an object to be cleaned. A cleaning voltage having a polarity opposite to the normal charging polarity (negative polarity) of the toner is applied to the rotating shaft of the cleaning brush roller by a power source.

  The transfer residual toner adhering to the surface of the intermediate transfer belt is electrostatically transferred from the surface of the intermediate transfer belt to the cleaning brush roller by the cleaning voltage while being scratched by the brush of the cleaning brush roller, and is removed from the intermediate transfer belt. Is done.

  In the cleaning device of the electrostatic cleaning system, the voltage applied to the rotating shaft of the cleaning brush roller may be a high voltage exceeding 1 [kV] in absolute value. The rotating shaft and a supporting member that supports the rotating shaft Therefore, it is necessary to suppress the occurrence of leak discharge. If the support member is made of a non-conductive resin, leakage discharge between the rotating shaft and the support member can be suppressed. However, since the resin is generally inferior in strength to metal, the support member It is necessary to make the wall thickness thicker than when metal is used, which leads to an increase in the size of the apparatus.

  Therefore, in order to reduce the size of the apparatus, it is conceivable to use a resin for the bearing portion that supports the rotating shaft and to use a metal for the bearing support portion that supports the bearing portion. In this case, it is necessary to increase the diameter of the bearing portion to keep the bearing support portion away from the rotation shaft so that leakage discharge does not occur between the rotation shaft and the bearing support portion.

  However, if the bearing support portion is too far away from the rotating shaft, the diameter of the bearing portion is increased more than necessary, which causes a problem that the apparatus is increased in size.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a cleaning device that can suppress the occurrence of leak discharge between the rotating shaft of the cleaning member and the support member while reducing the size of the device. And an image forming apparatus provided with the cleaning device.

  In order to achieve the above object, the invention of claim 1 is directed to removing a toner on a member to be cleaned, a cleaning member rotatably provided around a rotating shaft, and applying a voltage to the rotating shaft of the cleaning member. In the cleaning apparatus including a voltage applying unit to be applied and a support member that supports the rotating shaft, the support member includes a non-conductive bearing portion that supports the rotating shaft, and a metal that supports the bearing portion. The creepage distance that is the shortest distance along the surface of the support member from the contact position between the rotating shaft and the bearing portion to the bearing support portion is defined as X [mm]. The voltage applied to the rotating shaft by the voltage application means satisfies the relationship of X [mm] ≧ Y [kV] × 2 [mm / kV] where Y [kV]. is there.

  As described above, according to the present invention, there is an excellent effect that leakage discharge can be suppressed between the rotating shaft of the cleaning member and the support member while reducing the size of the apparatus.

The schematic diagram which shows the state by which the bearing part which supports a rotating shaft was attached to the reinforcement board. 1 is a schematic configuration diagram illustrating a main part of a printer according to an embodiment. FIG. 3 is a perspective explanatory view of an intermediate transfer belt showing a gradation pattern and an optical sensor of the printer. FIG. 3 is an enlarged schematic diagram illustrating a chevron patch formed on an intermediate transfer belt of the printer. FIG. 3 is a schematic diagram showing the intermediate transfer belt and a toner consumption pattern formed on the surface of the intermediate transfer belt. FIG. 3 is an enlarged configuration diagram illustrating a belt cleaning device of the printer. The expanded block diagram which expands and shows the 1st cleaning subunit in the cleaning apparatus, and its surrounding structure. The expanded block diagram which expands and shows the 2nd cleaning subunit in the cleaning apparatus, and its surrounding structure. The expanded block diagram which expands and shows the 3rd cleaning subunit in the cleaning apparatus, and its surrounding structure. The rear view which shows the back side board of the subunit holding | maintenance casing of the same cleaning apparatus. The rear view which shows the upper part of the back side board with the 3rd cleaning subunit. The partial expansion perspective view which shows the rear-end part and joint cap of the 3rd cleaning subunit. The partial expansion perspective view which shows the 3rd rear main positioning pin and the back side board of the 3rd cleaning subunit. The partial expansion perspective view which shows the 3rd back subpositioning pin and the back side board of the 3rd cleaning subunit. The perspective view which shows the cleaning unit drive part arrange | positioned at the transfer unit of the printer with a part of the 3rd cleaning subunit. The partial expansion perspective view which shows the front-end part of the same belt cleaning apparatus. FIG. 17 is a perspective explanatory view of a belt cleaning device in which a reinforcing plate, a bearing case, and a front plate handle are provided on the front plate shown in FIG. 16. Sectional drawing explaining the relationship between a bearing case and a reinforcement board. The schematic diagram which shows the state in which the bearing part which supports the rotating shaft in the belt cleaning apparatus which concerns on a modification was attached to the reinforcement board.

  Hereinafter, as an embodiment of an image forming apparatus to which the present invention is applied, a so-called tandem type intermediate transfer type printer (hereinafter simply referred to as a printer 500) will be described. First, the basic configuration of the printer 500 will be described. FIG. 2 is a schematic configuration diagram illustrating a main part of the printer 500.

  The printer 500 includes four process units 6Y, 6M, 6C, and 6K for generating toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). The four process units 6Y, 6M, 6C, and 6K have drum-shaped photoreceptors 1Y, 1M, 1C, and 1K, respectively.

  Around the photoreceptors 1Y, 1M, 1C, and 1K, charging devices 2Y, 2M, 2C, and 3K, developing devices 5Y, 5C, 1M, and 1K, drum cleaning devices 4Y, 4M, 4C, and 1K, a static eliminator (not shown). ) Etc. The process units 6Y, 6M, 6C, and 6K use Y, M, C, and K toners of different colors, but have the same configuration.

  Such a process unit 6 constitutes a part of the toner image creating means. Above the process units 6Y, 6M, 6C, and 6K, there is an optical writing unit (not shown) for irradiating the surface of the photoreceptors 1Y, 1M, 1C, and 1K with laser light L to write an electrostatic latent image. It is arranged.

  Below the process units 6Y, 6M, 6C, and 6K, a transfer unit 7 including an endless intermediate transfer belt 8 serving as an image carrier is disposed. In addition to the intermediate transfer belt 8, a plurality of stretching rollers disposed inside the loop, a secondary transfer roller 18, a tension roller 16, a belt cleaning device 100, a lubricant application device 200, and the like disposed outside the loop. have.

  Inside the loop of the intermediate transfer belt 8, four primary transfer rollers 9Y, 9M, 9C, 9K, a driven roller 10, a driving roller 11, a secondary transfer counter roller 12, and three cleaning counter rollers 13, 14 are provided. 15 and an application brush facing roller 17 are disposed. Each of these rollers functions as a stretching roller that stretches the intermediate transfer belt 8 around a part of its peripheral surface to stretch the belt.

  The cleaning counter rollers 13, 14, and 15 do not necessarily have to have a function of applying a constant tension, and may be driven to rotate as the intermediate transfer belt 8 rotates. The intermediate transfer belt 8 is moved endlessly in the clockwise direction as indicated by an arrow in the drawing by the rotation of the driving roller 11 that is driven to rotate counterclockwise in the drawing by a driving means (not shown).

  The four primary transfer rollers 9Y, 9M, 9C, and 9K disposed inside the belt loop sandwich the intermediate transfer belt 8 between the photoreceptors 1Y, 1M, 1C, and 1K. As a result, primary transfer nips for Y, M, C, and K where the front surface of the intermediate transfer belt 8 and the photoreceptors 1Y, 1M, 1C, and 1K come into contact are formed. A primary transfer bias having a polarity opposite to that of the toner is applied to the primary transfer rollers 9Y, 9M, 9C, and 9K by a power source (not shown).

  Further, the intermediate transfer belt 8 is sandwiched between the secondary transfer counter roller 12 disposed inside the belt loop and the secondary transfer roller 18 disposed outside the belt loop. As a result, a secondary transfer nip where the front surface of the intermediate transfer belt 8 and the secondary transfer roller 18 abut is formed.

  Note that a secondary transfer bias having a polarity opposite to that of the toner is applied to the secondary transfer roller 18 by a power source (not shown). Further, the paper transfer belt is bridged by the secondary transfer roller 18, several support rollers, and a drive roller, and the intermediate transfer belt 8 and the paper transfer belt are interposed between the secondary transfer roller 18 and the secondary transfer counter roller 12. It is good also as a structure which inserted | pinched.

  Further, the three cleaning facing rollers 13, 14, 15 disposed inside the belt loop are connected to three cleaning brush rollers (details will be described later) of the belt cleaning device 100 disposed outside the belt loop. The intermediate transfer belt 8 is sandwiched between the two. Thus, a cleaning nip is formed in which the front surface of the intermediate transfer belt 8 and the three cleaning brush rollers abut.

  The belt cleaning device 100 can be replaced integrally with the transfer unit 7. Further, the belt cleaning device 100 can be removed from the transfer unit 7 removed from the printer 500 main body. Further, a cleaning subunit, which will be described later, in the belt cleaning device 100 can be attached to and detached from the belt cleaning device 100 while the transfer unit 7 and the belt cleaning device 100 are attached to the printer 500 main body. Details of the belt cleaning device 100 will be described later.

  The printer 500 includes a paper feeding unit (not shown) having a paper feeding cassette that stores the recording paper P, a paper feeding roller that feeds the recording paper P from the paper feeding cassette to the paper feeding path, and the like. In addition, a registration roller pair (not shown) that receives the recording paper sent from the paper feeding unit and feeds it at a predetermined timing toward the secondary transfer nip is provided on the right side of the secondary transfer nip in the drawing.

  In addition, a fixing device (not shown) that receives the recording paper P sent out from the secondary transfer nip and fixes the toner image to the recording paper P is provided on the left side of the secondary transfer nip in the drawing. . Further, Y, M, C, and K toner supply devices (not shown) for supplying Y, M, C, and K toners to the developing devices 5Y, M, C, and K are provided as necessary.

  In recent years, in addition to plain paper that has been widely used as recording paper, special recording paper that is used for thermal transfer such as special paper having an uneven surface or iron print as a design has been increasingly used. When such special paper is used, transfer defects are more likely to occur when the toner image on the intermediate transfer belt 8 on which the color toners are superimposed is secondarily transferred onto the paper, as compared with conventional plain paper.

  Therefore, in the printer 500, an elastic layer having a low hardness is provided on the intermediate transfer belt 8 so that the toner layer and recording paper with poor smoothness can be deformed at the transfer nip portion. By providing the intermediate transfer belt 8 with an elastic layer having low hardness and making the intermediate transfer belt 8 elastic, the surface of the intermediate transfer belt 8 can be deformed following local irregularities. Thereby, without excessively increasing the transfer pressure with respect to the toner layer, good adhesion can be obtained, there is no loss of transfer of characters, and there is no transfer unevenness even on paper with poor smoothness, A transfer image having excellent uniformity can be obtained.

  In the printer 500, the intermediate transfer belt 8 includes at least a base layer, an elastic layer, and a surface coat layer. Examples of the material used for the elastic layer of the intermediate transfer belt 8 include elastic members such as elastic material rubber and elastomer.

  Specifically, butyl rubber, fluorine rubber, acrylic rubber, EPDM, NBR, acrylonitrile-butadiene-styrene rubber, natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, urethane rubber, syndiotactic 1,2-polybutadiene , Epichlorohydrin rubber, polysulfide rubber, polynorbornene rubber, thermoplastic elastomer (for example, polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyamide, polyurea, polyester, fluorine resin) One type or two or more types selected from the group can be used. However, it is not limited to these materials.

  The thickness of the elastic layer depends on the hardness and the layer structure, but is preferably in the range of 0.07 to 0.5 [mm]. More preferably, the range of 0.25-0.5 [mm] is good. Further, if the thickness of the intermediate transfer belt 8 is as thin as 0.07 [mm] or less, the pressure on the toner on the intermediate transfer belt 8 at the secondary transfer nip portion becomes high, and transfer deficiency is likely to occur. The toner transfer rate decreases.

  The hardness of the elastic layer is preferably 10 [°] ≦ HS ≦ 65 [°] (JIS-A). Although the optimum hardness varies depending on the layer thickness of the intermediate transfer belt 8, if the hardness is lower than 10 [°] (JIS-A), transfer dipping is likely to occur. On the other hand, when the hardness is higher than 65 [°] JIS-A, it is difficult to stretch the roller, and since it is stretched by long-term stretching, there is no durability and early replacement is necessary.

  The base layer of the intermediate transfer belt 8 is made of a resin with little elongation. Specifically, materials used for the base layer include polycarbonate, fluororesin (ETFE, PVDF, etc.), polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, Styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer) Styrene-octyl acrylate copolymer and styrene-phenyl acrylate copolymer), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene) -Phenyl methacrylate copolymer, etc.), steel -Α-chloromethyl acrylate copolymer, styrene resin such as styrene-acrylonitrile-acrylate ester copolymer (monopolymer or copolymer containing styrene or styrene substitution product), methyl methacrylate resin, methacryl Acid butyl resin, ethyl acrylate resin, butyl acrylate resin, modified acrylic resin (silicone modified acrylic resin, vinyl chloride resin modified acrylic resin, acrylic / urethane resin, etc.), vinyl chloride resin, styrene-vinyl acetate copolymer, chloride Pinyl-vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin, polyester polyurethane resin, polyethylene, polypropylene, polybutadiene, polyvinylidene chloride, ionomer resin, polyurethane resin, silicone Fat, ketone resins, ethylene - can be used ethyl acrylate copolymer, xylene resin and polyvinyl butyral resin, polyamide resin, one kind or two kinds or more selected from the group consisting of modified polyphenylene oxide resin. However, it is not limited to these materials.

  In addition, in order to prevent the elastic layer made of a rubber material having a large elongation from extending, a core layer made of a material such as a canvas may be provided between the base layer and the elastic layer. Examples of materials for preventing elongation used in the core layer include natural fibers such as cotton and silk, polyester fibers, nylon fibers, acrylic fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, and polyvinylidene chloride fibers. , One or more selected from the group consisting of synthetic fibers such as polyurethane fiber, polyacetal fiber, polyfluoroethylene fiber and phenol fiber, inorganic fibers such as carbon fiber and glass fiber, and metal fibers such as iron fiber and copper fiber Threaded or woven fabric can be used.

  Of course, the material is not limited to the above. The above-described yarn may be twisted in any manner, such as one or a plurality of filaments twisted, one-twisted yarn, various twisted yarns, double yarn, or the like. Further, for example, fibers of a material selected from the above material group may be blended. Of course, the yarn can be used after being subjected to an appropriate conductive treatment. On the other hand, as the woven fabric, any woven fabric such as knitted fabric can be used, a cross-woven fabric can be used, and a conductive treatment can be performed.

  The coat layer on the surface of the intermediate transfer belt 8 is for coating the surface of the elastic layer, and is composed of a layer having good smoothness. The material used for the coating layer is not particularly limited, but generally, a material that increases the secondary transferability by reducing the amount of toner adhering to the surface of the intermediate transfer belt 8 is used.

  For example, one or more types of polyurethane, polyester, epoxy resin, etc., or materials that reduce surface energy and increase lubricity, such as fluorine fats, fluorine compounds, fluorocarbons, titanium oxide, silicon carbide, etc. Can be used by dispersing one type or two or more types or changing the particle size as required. Further, it is also possible to use a material such as a fluorine-based rubber material in which a heat treatment is performed to form a fluorine layer on the surface and the surface energy is reduced.

  If necessary, the base layer, the elastic layer, or the coating layer is, for example, carbon black, graphite, metal powder such as aluminum or nickel, tin oxide, titanium oxide, antimony oxide, indium oxide, for the purpose of adjusting resistance. Conductive metal oxides such as potassium titanate, antimony oxide-tin oxide composite oxide (ATO), and indium oxide-tin oxide composite oxide (ITO) can be used. Here, the conductive metal oxide may be coated with insulating fine particles such as barium sulfate, magnesium silicate, and calcium carbonate. However, it is not limited to these materials.

  The surface of the intermediate transfer belt 8 is coated with a lubricant by a lubricant coating device 200 in order to protect the belt surface. The lubricant application device 200 is a coating that abuts on the surface of the intermediate transfer belt 8 with a solid lubricant 202 such as a zinc stearate lump and a lubricant powder that comes into contact with the solid lubricant and is scraped off from the solid lubricant by rotation. And a coating brush roller 201 as a member. Although the printer 500 is provided with the lubricant application device 200, it may not be necessary depending on the toner to be used, the material of the intermediate transfer belt 8, and the surface friction coefficient.

  When image information is sent from a personal computer or the like, the printer 500 rotates the drive roller 11 to move the intermediate transfer belt 8 endlessly. The stretching rollers other than the driving roller 11 are driven and rotated by the belt. At the same time, the photosensitive members 1Y, 1M, 1C, and 1K of the process units 6Y, 6M, 6C, and 6K are rotationally driven. Further, an electrostatic latent image is formed by irradiating the charged surface with laser light L while uniformly charging the surfaces of the photoreceptors 1Y, 1M, 1C, and 1K with the charging devices 2Y, 2M, 2C, and 2K. To do.

  The electrostatic latent images formed on the surfaces of the photoreceptors 1Y, 1M, 1C, and 1K are developed by the developing devices 5Y, 5M, 5C, and 5K, so that the Y, M on the photoreceptors 1Y, 1M, 1C, 1K are developed. , C, K toner images are obtained. The Y, M, C, and K toner images are primarily transferred while being superimposed on the front surface of the intermediate transfer belt 8 in the above-described primary transfer nips for Y, M, C, and K. As a result, a four-color superimposed toner image is formed on the front surface of the intermediate transfer belt 8.

  On the other hand, in a paper feeding unit (not shown), the recording paper P is sent out one by one from the paper feeding cassette by the paper feeding roller and conveyed to the registration roller pair. Then, at a timing that can be synchronized with the four-color superimposed toner image on the intermediate transfer belt 8, the registration roller pair is driven to feed the recording paper P to the secondary transfer nip, and the four-color superimposed toner image on the belt is transferred. Batch transfer onto the recording paper P is performed. Thereby, a full-color image is formed on the surface of the recording paper P. The recording paper P after the formation of a full-color image is conveyed from the secondary transfer nip to a fixing device (not shown) and subjected to toner image fixing processing.

  For the photoreceptors 1Y, M, C, and K after the Y, M, C, and K toner images are primarily transferred to the intermediate transfer belt 8, the remaining toner is cleaned by the drum cleaning devices 4Y, 4M, 4C, and 4K. Apply. Then, after neutralizing with a neutralizing lamp (not shown), it is uniformly charged with the charging devices 2Y, 2M, 2C, and 3K, and is ready for the next image formation. Further, the intermediate transfer belt 8 after the primary transfer to the recording paper P is subjected to a cleaning process for residual toner by the belt cleaning device 100.

  On the right side of the K process unit 6K in the figure, an optical sensor unit 90 is disposed so as to face the front surface of the intermediate transfer belt 8 with a predetermined gap. As shown in FIG. 3, the optical sensor unit 90 includes a Y optical sensor 91Y, a C optical sensor 91C, an M optical sensor 91M, and a K optical sensor 91K arranged in the width direction of the intermediate transfer belt 8.

  Each of these sensors is a reflection type photosensor, and reflects light emitted from a light emitting element (not shown) by a toner image on the front surface of the intermediate transfer belt 8 or the belt, and detects the amount of reflected light by a light receiving element (not shown). To do. A control unit (not shown) can detect the toner image on the intermediate transfer belt 8 or the image density (toner adhesion amount per unit area) based on the output voltage values from these sensors. .

  The printer 500 executes image density control for optimizing the image density of each color when the power is turned on or whenever a predetermined number of prints are performed. In the image density control, first, gradation patterns Sk, Sm, Sc, Sy of each color as shown in FIG. 3 are formed on the intermediate transfer belt 8 at positions facing the optical sensors 91Y, 91M, 91C, 91K. To do. The gradation pattern of each color is composed of 10 toner patches having an area of 2 [cm] × 2 [cm] having different image densities.

  The charging potentials of the photoreceptors 1Y, 1M, 1C, and 1K when creating the gradation patterns Sk, Sm, Sc, and Sy for each color are different from the uniform drum charging potential in the printing process and gradually increase in value. To do. Then, while forming a plurality of patch electrostatic latent images for forming a gradation pattern image on the photoreceptors 1Y, 1M, 1C, and 1K by scanning with laser light, they are used for Y, M, C, and K, respectively. Development is performed by the developing devices 5Y, 5M, 5C, and 5K.

During this development, the value of the developing bias applied to the Y, M, C, and K developing rollers is gradually increased. By such development, gradation pattern images of Y, M, C, and K are formed on the photoreceptors 1Y, 1M, 1C, and 1K. These are primarily transferred so as to be arranged at a predetermined interval in the main scanning direction of the intermediate transfer belt 8. At this time, the toner adhesion amount of the toner patch in the gradation pattern of each color is about 0.1 [mg / cm ² ] at the minimum and 0.55 [mg / cm ² ] at the maximum, and the toner Q / d distribution When measured, it is almost aligned with the regular charging polarity.

  Each toner pattern (Sk, Sm, Sc, Sy) formed on the intermediate transfer belt 8 passes through a position facing the optical sensor 91 as the intermediate transfer belt 8 moves endlessly. At this time, the optical sensor 91 receives an amount of light corresponding to the toner adhesion amount per unit area with respect to the toner patch of each gradation pattern.

  Next, from the output voltage of the optical sensor 91 when each color toner patch is detected and the adhesion amount conversion algorithm, the adhesion amount of each color toner pattern in each toner patch is calculated, and the image forming condition is based on the calculated adhesion amount. Adjust.

  Specifically, a function (y = ax + b) indicating a straight line graph is calculated by regression analysis based on the result of detecting the toner adhesion amount on the toner patch and the development potential when each toner patch is imaged. Then, an appropriate development bias value is calculated by substituting a target value of image density into this function, and development bias values for Y, M, C, and K are specified.

  The memory stores an image forming condition data table in which several tens of development bias values and appropriate drum charging potentials individually corresponding to the values are associated in advance. For each of the process units 6Y, 6M, 6C, and 6K, a developing bias value closest to the specified developing bias value is selected from the image forming condition table, and the drum charging potential associated therewith is specified.

  The printer 500 also performs color misregistration correction processing when the power is turned on or whenever a predetermined number of prints are performed. In this color misregistration correction process, Y, M, C, and K color toners called chevron patches PV as shown in FIG. 4 are respectively provided at one end and the other end of the intermediate transfer belt 8 in the width direction. An image for color misregistration detection composed of an image is formed.

As shown in FIG. 4, the chevron patch PV is predetermined in the belt moving direction, which is the sub-scanning direction, with the Y, M, C, and K color toner images inclined at about 45 [°] from the main scanning direction. A line pattern group arranged in a pitch. The amount of the chevron patch PV attached is about 0.3 [mg / cm ² ].

  Each color toner image in the chevron patch PV formed at both ends in the width direction of the intermediate transfer belt 8 is detected. As a result, the position in the main scanning direction (photosensitive member axis direction), the position in the sub-scanning direction (belt movement direction), the magnification error in the main scanning direction, and the skew from the main scanning direction are detected in each color toner image. The main scanning direction is a direction in which the laser light is phased on the surface of the photosensitive member as it is reflected by the polygon mirror.

  For such Y, M, C toner images in the chevron patch PV, the optical sensor 91 reads the detection time difference from the K toner image. In the figure, the vertical direction of the paper surface corresponds to the main scanning direction, and after the Y, M, C, and K toner images are arranged in order from the left, the postures are different from those by 90 [°]. , Y toner images are further arranged.

  Based on the difference between the actual measurement value and the theoretical value of the detection time differences tyk, tmk, and tck with respect to K as the reference color, the shift amount in the sub-scanning direction of each color toner image, that is, the registration shift amount is obtained. Then, based on the amount of registration deviation, light on the photosensitive member 1 is formed with every other polygon mirror of an optical writing unit (not shown), which is a part of the toner image forming unit, on one surface, that is, with one scanning line pitch as one unit. The registration start of each color toner image is reduced by correcting the writing start timing.

  Further, the inclination (skew) of each color toner image from the main scanning direction is obtained based on the difference in the amount of deviation in the sub-scanning direction between both ends of the belt. Based on the result, surface tilt correction of the optical system reflection mirror is performed to reduce skew of each color toner image.

  As described above, the color misregistration correction process is a process that corrects the optical writing start timing and surface tilt based on the detection timing of each toner image in the chevron patch PV to reduce registration deviation and skew deviation. By such a color misregistration correction process, it is possible to suppress the occurrence of color misregistration of an image due to a shift in the formation position of each color toner image with respect to the intermediate transfer belt 8 due to a temperature change or the like.

  Further, if the image forming operation with a low image area continues, the amount of old toner that stays in the developing device 5 for a long time increases, so that the toner charging characteristics deteriorate and the image quality deteriorates when used for image formation (deterioration of developing ability). , Transferability decline). In order to prevent such old toner from staying in the developing device, the toner is discharged to a non-image area of the photosensitive member 1 at a fixed timing, and new toner is replenished to the developing device whose toner density has been lowered after the discharging to refresh the inside of the developing device. It has a refresh mode.

  A control unit (not shown) stores the toner consumption amounts of the developing devices 5Y, 5M, C, and K and the operation times of the developing devices 5Y, M, C, and K. Then, at a predetermined timing, each developing device is checked whether or not the toner consumption amount is equal to or less than a threshold with respect to the operation time of the developing device for a predetermined period, and the refresh mode is executed for the developing device below the threshold.

When the refresh mode is executed, a toner consumption pattern ((a) in FIG. 5) is created in the non-image forming area corresponding to the space between the sheets of the photoreceptor 1 and transferred to the intermediate transfer belt 8. The adhesion amount of the toner consumption pattern is determined based on the toner consumption amount with respect to the operation time of the developing device for a predetermined period, and the maximum adhesion amount per unit area on the intermediate transfer belt is about 1.2 [mg / cm ² ]. May be.

  Further, when the toner Q / d distribution of the toner consumption pattern (a) transferred to the intermediate transfer belt 8 is measured, it is substantially aligned with the normal charging polarity. In this embodiment, the size of the toner consumption pattern is 25 [mm] × 250 [mm].

  The toner of each color gradation pattern, chevron patch, and toner consumption pattern formed on the intermediate transfer belt 8 is transferred to the secondary transfer roller 18 and removed by a secondary transfer roller cleaning unit (not shown). The remaining toner that has not been transferred to the secondary transfer roller 18 is collected by the belt cleaning device 100.

  FIG. 6 is an enlarged configuration diagram showing the belt cleaning device 100. In the figure, a belt cleaning apparatus 100 includes a first cleaning subunit 101 and a second cleaning subunit 111 adjacent thereto on the downstream side in the belt moving direction. Further, it also has a third cleaning subunit 121 adjacent to the second cleaning subunit 111 on the downstream side in the belt moving direction.

  The first cleaning subunit 101 has a first cleaning brush roller 102 as a cleaning member that scrapes off the transfer residual toner from the surface of the intermediate transfer belt 8. Also, a first recovery roller 103 that rotates while contacting the first cleaning brush roller 102 to recover the transfer residual toner from the brush roller, and a first scraping blade that scrapes the transfer residual toner from the surface of the first recovery roller 103 104 or the like. The first subunit casing 106 as a holding body also includes a first conveying screw 105 that discharges transfer residual toner scraped off from the first recovery roller 103 to the outside of the first subunit casing 106. .

  Similar to the first cleaning subunit 101, the second cleaning subunit 111 has the following configuration. That is, the second cleaning brush roller 112, the second recovery roller 113, the second scraping blade 114, the second conveying screw 115, and the second subunit casing 116, which are cleaning members. The third cleaning subunit 121 also has the following configuration, similar to the first cleaning subunit 101. That is, the third cleaning brush roller 122, the third collection roller 123, the third scraping blade 124, the third transport screw 125, and the third subunit casing 126, which are cleaning members.

  The first cleaning subunit 101, the second cleaning subunit 111, and the third cleaning subunit 121 are individually attached to and detached from the subunit holding casing 150 that is a subunit holder of the belt cleaning device. .

  Most of the toner constituting the untransferred toner is charged with a polarity opposite to the normal charging polarity (negative polarity), depending on the original toner charge amount. Therefore, in the first cleaning subunit 101 located on the most upstream side of the three cleaning subunits, the cleaning bias having the same polarity (negative polarity) as the normal charging polarity of the toner is applied to the first cleaning brush roller 102. Is applied from the power source.

  As a result, the transfer residual toner charged to the reverse polarity (positive polarity) on the intermediate transfer belt 8 is electrostatically captured in the brush of the first cleaning brush roller 102. A negative recovery bias having an absolute value larger than the above-described cleaning bias is applied to the first recovery roller 103 from a power source.

  The first cleaning brush roller 102 injects negative charge having a normal charging polarity to the reversely charged toner particles on the surface of the intermediate transfer belt 8 to return the reversely charged toner particles to the normal polarity. It also functions as a means.

  The transfer residual toner includes regular charged polarity toner. Therefore, a cleaning bias having a polarity opposite to the normal charging polarity (negative polarity) of the toner is applied to the second cleaning brush roller 112 of the second cleaning subunit 111 from a power source.

  As a result, among the transfer residual toner, regular charged toner particles are electrostatically captured in the brush of the second cleaning brush roller 112. A positive and negative recovery bias having an absolute value larger than the above-described cleaning bias is applied to the second recovery roller 113 from a power source.

  A positive cleaning bias that is opposite to the normal charging polarity of the toner is applied to the third cleaning brush roller 122 of the third cleaning subunit 121. Further, a positive recovery bias having an absolute value larger than the above-described cleaning bias is applied to the third recovery roller 123 from the power source.

  In the second subunit casing 116 of the second cleaning subunit 111, a first insulating seal member 171 for preventing the toner from falling is provided in the vicinity of the opening for exposing the second cleaning brush roller 112. ing. The first insulating seal member 171 prevents discharge between the first cleaning brush roller 102 and the second cleaning brush roller 112. Further, toner transfer from the second subunit casing 116 to the first subunit casing 106 is prevented.

  In the third subunit casing 126 of the third cleaning subunit 121, a second insulating seal member 172 for preventing the toner from falling is provided in the vicinity of the opening for exposing the third cleaning brush roller 122. ing. The second insulating seal member 172 prevents discharge between the third cleaning brush roller 122 and the second cleaning brush roller 112. Further, toner transfer from the third subunit casing 126 to the second subunit casing 116 is prevented.

  In the third subunit casing 126 of the third cleaning subunit 121, a third insulating seal member 173 is provided above the opening for exposing the third cleaning brush roller 122. The third insulating seal member 173 prevents discharge between the third cleaning brush roller 122 and the tension roller (reference numeral 16 in FIG. 2).

  Each of the three cleaning brush rollers (102, 112, 122) includes a metal rotary shaft member that is rotatably supported and a brush portion that includes a plurality of raised brushes erected on the peripheral surface thereof. The outer diameter is 15 to 16 [mm]. The raised nail has a two-layer core-sheath structure in which the inside is made of a conductive material such as conductive carbon and the surface portion is made of an insulating material such as polyester.

  As a result, the lead has substantially the same potential as the cleaning bias applied to the cleaning brush rollers (102, 112, 122), and the toner can be electrostatically attracted to the raised surface. As a result, the toner on the intermediate transfer belt 8 is captured by the raised brushes of the cleaning brush rollers (102, 112, 122).

  In addition, you may comprise the raising | fluff of the cleaning brush roller (102,112,122) only with a conductive fiber instead of the core-sheath structure of a two-layer structure. Moreover, you may make it the so-called oblique hair planted in the attitude | position inclined with respect to the normal line direction of a rotating shaft member. Further, the raised portions of the first cleaning brush roller 102 and the third cleaning brush roller 122 to which a positive cleaning bias is applied may have a core-sheath structure, and the raised portions of the second cleaning brush roller 112 may be formed of only conductive fibers. Good.

  By forming the raised portions of the second cleaning brush roller 112 to which a negative cleaning bias is applied only with conductive fibers, it is possible to easily generate charge injection from the second cleaning brush roller 112 to the toner. Therefore, the second cleaning brush roller 112 can satisfactorily align the toner on the intermediate transfer belt 8 with negative polarity.

  On the other hand, the brushing of the first cleaning brush roller 102 and the third cleaning brush roller 122 has a core-sheath structure, so that charge injection into the toner can be suppressed, and the toner on the intermediate transfer belt 8 is charged positively. To suppress. Thereby, it is possible to prevent the first cleaning brush roller 102 and the third cleaning brush roller 122 from generating toner that cannot be removed electrostatically.

  Further, the three cleaning brush rollers (102, 112, 122) are bitten into the intermediate transfer belt 8 by a biting amount of 1 [mm]. The brush roller is rotationally driven by a driving means (not shown) so as to move the raised hair in the contact position in the direction opposite to the moving direction of the intermediate transfer belt 8 (counter direction).

  The linear velocity difference between the cleaning brush roller and the intermediate transfer belt 8 can be increased by rotating the raised brush so as to move in the counter direction at the contact position. This increases the probability of contact with the raised hair until a portion of the intermediate transfer belt 8 passes through the contact range with the cleaning brush roller, and the toner can be removed from the intermediate transfer belt 8 satisfactorily.

  As the three collection rollers (103, 113, 123), all are made of SUS (stainless steel) rollers. The collection rollers (103, 113, 123) may be made of any material as long as the following functions can be exhibited. In other words, the toner adhering to the cleaning brush rollers (102, 112, 122) is transferred from the cleaning brush roller to the collecting roller by the potential gradient between the raised brush and the collecting roller.

  For example, as a collecting roller, a roller resistance is set to log R = 12 to 13 [Ω] by covering a conductive core metal with a high resistance elastic tube of several [μm] to 100 [μm] or by insulating coating. May be used. By using a roller made of stainless steel as the collection roller, there are merits that the cost can be reduced, the applied voltage can be kept low, and the power can be saved.

  On the other hand, by setting the roller resistance to logR = 12 to 13 [Ω], the charge injection into the toner during the collection to the collection roller is suppressed, and the toner has the same polarity as the applied voltage of the collection roller. It can suppress that a recovery rate falls.

The conditions of the three cleaning brush rollers (102, 112, 122) are as follows.
・ Brush material: Conductive polyester (Contains conductive carbon inside the fiber, the fiber surface is polyester, so-called core-sheath structure)
・ Brush resistance: 10E6 to 10E8 [Ω]
・ Brush flocking density: 60,000 to 150,000 [lines / inch ² ]
・ Brush fiber diameter: about 25 to 35 [μm]
-Brush tipping treatment: None-Brush diameter φ: 14-20 [mm]
-Brush fiber biting amount into the intermediate transfer belt 8: 1 [mm]

  The cleaning bias applied to the first cleaning brush roller 102 is set to such a value that a good cleaning performance can be obtained when a large amount of untransferred toner is generated on the intermediate transfer belt 8. Further, the absolute value is set high so that electric charge is injected into the toner on the intermediate transfer belt 8. Further, the brush flocking density, brush resistance, fiber diameter, applied voltage, fiber type, and brush fiber biting amount can be optimized by the system, and thus are not limited thereto. Examples of the types of fibers that can be used include nylon, acrylic, and polyester.

The conditions of the three collection rollers (103, 113, 123) are as follows.
・ Recovery roller core material: Stainless steel (SUS303)
-Brush fiber biting amount into the collection roller: 1.5 [mm]
The collection roller material, brush fiber entrapment amount, and applied voltage can be optimized by the system, and are not limited thereto.

The conditions of the three scraping blades (104, 114, 124) are as follows.
・ Material: Stainless steel (SUS304)
・ Blade contact angle: 20 [°]
・ Blade thickness: 0.1 [mm]
・ Blade biting amount into collection roller: 1.0 [mm]
The blade contact angle, the blade thickness, and the amount of biting into the collection roller can be optimized by the system, and are not limited thereto.

  In FIG. 6, the untransferred toner that has passed through the secondary transfer nip (not shown) passes through the contact portion between the inlet seal 174 and the belt and moves to the position of the first cleaning brush roller 102 as the intermediate transfer belt 8 moves. Be transported. A cleaning bias having a normal charging polarity of toner is applied to the first cleaning brush roller 102.

  Due to the electric field formed by the potential difference between the surface potential of the intermediate transfer belt 8 and the first cleaning brush roller 102, the positively and negatively charged toner on the intermediate transfer belt 8 is electrostatically applied to the brush of the first cleaning brush roller 102. Adsorb. The negative toner transferred to the first cleaning brush roller 102 is transferred to a contact position with the first recovery roller 103 to which a positive recovery bias having a value larger than that of the first cleaning brush roller 102 is applied.

  Then, due to the electric field formed by the potential difference between the surface potential of the first cleaning brush roller 102 and the surface potential of the first recovery roller 103, the transfer residual toner in the brush of the first cleaning brush roller 102 is transferred onto the first recovery roller 103. Is electrostatically transferred to. Then, after being scraped off from the surface of the first recovery roller 103 by the first scraping blade 104, it is transported by a first transport screw 105 to a toner storage portion (not shown) of the first cleaning subunit 101.

  The transfer residual toner on the intermediate transfer belt 8 that could not be removed by the first cleaning brush roller 102 includes negative polarity toner. These transfer residual toners are transferred to a contact position with the second cleaning brush roller 112.

  A voltage having a polarity (positive polarity) opposite to the normal charging polarity of the toner is applied to the second cleaning brush roller 112. Therefore, the toner is transferred into the brush of the second cleaning brush roller 112 by an electric field formed by a potential difference between the surface potential of the intermediate transfer belt 8 and the surface potential of the second cleaning brush roller 112.

  Thereafter, after electrostatic transfer to the second recovery roller 113, the second cleaning blade 114 is scraped off from the second recovery roller 113, and then the second cleaning subunit 111 is not shown by the second transport screw 115. It is transported to the toner reservoir.

  The negative toner that has not been completely removed by the second cleaning brush roller 112 is transferred to a contact position with the third cleaning brush roller 122 as the belt moves. The amount of negative polarity toner transferred in this manner is very small. The toner is electrostatically transferred sequentially to the third cleaning brush roller 122 and the third recovery roller 123 and then scraped off from the third recovery roller 123 by the third scraping blade 124. Then, the toner is transported to a toner storage portion (not shown) of the third cleaning subunit 121 by the third transport screw 125.

Next, the configuration of the cleaning subunit of the printer 500 will be described.
FIG. 7 is an enlarged configuration diagram illustrating the first cleaning subunit 101 and the surrounding configuration in the belt cleaning device 100 in an enlarged manner.

  The subunit holding casing 150 of the belt cleaning device 100 has two support portions for detachably supporting the first cleaning subunit 101. It is the 1st left support part 151 as an one end support part, and the 1st right support part 152 as an other end support part.

  In the state where the first cleaning subunit 101 is completely set in the subunit holding casing 150, the first subunit casing 106 is removed from the first left support portion 151 and the first right support portion 152 as shown in the figure. It will be in a floating state. On the other hand, during the operation of sliding the first cleaning sub-unit 101 in the longitudinal direction with respect to the sub-unit holding casing 150 and attaching / detaching the first sub-unit 101, the first sub-unit casing 106 includes the first left support 151 and the first support It is placed on the right support part 152.

  The first left support portion 151 supports the left end portion as one end portion in the short direction (left-right direction in the drawing) of the first subunit casing 106 of the first cleaning subunit 101 from below in the vertical direction. More specifically, the left end portion of the first subunit casing 106 is supported so as to be slidable in the longitudinal direction of the first subunit casing 106 (the direction orthogonal to the paper surface of the drawing), and in the lateral direction of the left end portion. Allow to move.

  The first left support portion 151 can support the left end portion slidably in the longitudinal direction by a receiving portion that receives the left end portion in a state of extending in the longitudinal direction. It does not have any part that prevents the left end from moving in the short direction. For this reason, movement in the short direction of the left end is allowed.

  The first right support portion 152 supports the right end portion as the other end portion in the short direction of the first subunit casing 106 of the first cleaning subunit 101 from below in the vertical direction. More specifically, the first right support portion 152 slides the left end portion in the longitudinal direction by the receiving portion that receives the right end portion of the first subunit casing while extending in the longitudinal direction of the first subunit casing 106. Support in a movable manner. The first right support portion 152 includes a left side wall located on the left side of the right end portion of the first subunit casing 106 and a right side wall located on the right side of the right end portion in addition to the receiving portion described above. doing.

  The right end of the first subunit casing 106 is inserted between the left side wall and the right side wall of the first right support part 152. The distance between the left side wall and the right side wall is set to be larger than the length in the short side direction of the right end portion of the first subunit casing 106. Therefore, as shown in the drawing, between the right end portion of the first subunit casing 106 and the left side wall of the first right support portion 152, the right end portion, and the right side wall of the first right support portion 152 A gap G is formed between the two. The first right support portion 152 allows the right end portion of the first subunit casing 106 to move in the short direction within the range of the total size of the gaps G.

  In such a configuration, it is assumed that the size in the short direction of the first subunit casing 106 serving as the holding body is larger than the design value within the playable range described above. Even in such a case, the first subunit casing 106 can be inserted between the first left support portion 151 and the first right support portion 152 and supported by these support portions. Therefore, even if the first subunit casing 106 has a dimensional error or extension in the short direction, the first cleaning subunit 101 can be mounted on the subunit holding casing 150.

  FIG. 8 is an enlarged configuration diagram showing the second cleaning subunit 111 and its surrounding configuration in the belt cleaning device 100 in an enlarged manner. The subunit holding casing 150 of the belt cleaning device 100 has two support portions for detachably supporting the second cleaning subunit 111. It has the 2nd left support part 153 as an end support part, and the 2nd right support part 154 as an other end support part.

  In the state where the second cleaning subunit 111 is completely set in the subunit holding casing 150, the second subunit casing 116 is removed from the second left support portion 153 and the second right support portion 154 as shown in the figure. It will be in a floating state. On the other hand, when the second cleaning sub-unit 111 is slidably moved in the longitudinal direction with respect to the sub-unit holding casing 150 and attached / detached, the second sub-unit casing 116 is connected to the second left support portion 153 and the second sub-unit casing 153. It rests on the two right support parts 154.

  The second left support portion 153 supports the left end portion as one end portion in the short direction of the second subunit casing 116 of the second cleaning subunit 111 from below in the vertical direction. The left end portion of the second subunit casing 116 is supported so as to be slidable in the longitudinal direction, while allowing the left end portion to move in the short direction.

  The second right support portion 154 supports the right end portion as the other end portion in the short direction of the second subunit casing 116 from below in the vertical direction. The left end portion is supported so as to be slidable in the longitudinal direction by a receiving portion that receives the right end portion of the second subunit casing 116 in a state of extending in the longitudinal direction of the second subunit casing 116. The second right support part 154 includes a left side wall and a right side wall in addition to the receiving part described above.

  The right end portion of the second subunit casing 116 is inserted between the left side wall and the right side wall of the second right support portion 154. The distance between the left side wall and the right side wall is set to be greater than the length in the short side direction of the right end portion of the second subunit casing 116. Therefore, as shown, between the right end of the second subunit casing 116 and the left side wall of the second right support 154, the right end, and the right side wall of the second right support 154 A gap G is formed between the two. The second right support portion 154 allows the right end portion of the second subunit casing 116 to move in the short direction within the range of the total size of the gaps G.

  In such a configuration, the second cleaning subunit 111 can be mounted on the subunit holding casing 150 even if the second subunit casing 116 has a dimensional error or extension in the short direction.

  FIG. 9 is an enlarged configuration diagram showing the third cleaning subunit 121 and its surrounding configuration in the belt cleaning device 100 in an enlarged manner. The subunit holding casing 150 of the belt cleaning device 100 has two support portions for detachably supporting the third cleaning subunit 121. It has a third left support portion 155 as one end support portion and a third right support portion 156 as another end support portion.

  In the state where the third cleaning subunit 121 is completely set in the subunit holding casing 150, the third subunit casing 126 is removed from the third left support portion 155 and the third right support portion 156 as shown in the figure. It will be in a floating state. On the other hand, when the third cleaning sub-unit 121 is slidably moved in the longitudinal direction with respect to the sub-unit holding casing 150 and attached / detached, the third sub-unit casing 126 is connected to the third left support portion 155 and the third left support portion 155. Three on the right support 156.

  The third left support portion 155 supports the left end portion as one end portion in the short direction of the third subunit casing 126 of the third cleaning subunit 121 from below in the vertical direction.

  The left end portion of the third subunit casing 126 is supported so as to be slidable in the longitudinal direction, while allowing the left end portion to move in the short direction. The third right support portion 156 supports the right end portion as the other end portion in the short direction of the third subunit casing 126 from below in the vertical direction. The left end portion is supported so as to be slidable in the longitudinal direction by the receiving portion that receives the right end portion of the third subunit casing 126 in a state of extending in the longitudinal direction of the third subunit casing 126.

  The third right support part 156 includes a left side wall and a right side wall in addition to the receiving part described above. The right end portion of the third subunit casing 126 is inserted between the left side wall and the right side wall of the third right support portion 156.

  The distance between the left side wall and the right side wall is set to be larger than the length in the short side direction of the right end portion of the third subunit casing 126. For this reason, as shown in the drawing, between the right end of the third subunit casing 126 and the left side wall of the third right support 156, the right end, and the right side wall of the third right support 156 A gap G is formed between the two. The third right support portion 156 allows the right end portion of the third subunit casing 126 to move in the short direction within the range of the total size of the gaps G.

  In such a configuration, the third cleaning subunit 121 can be mounted on the subunit holding casing 150 even if the third subunit casing 126 has a dimensional error or extension in the short direction.

  Note that the three cleaning subunits (101, 11, 121) are pushed into the subunit holding casing 150 and mounted while being slid from the near side to the far side in the direction orthogonal to the paper surface of FIG. The On the other hand, it is taken out from the subunit holding casing 150 while being slid from the back side to the front side in the direction orthogonal to the drawing sheet.

  Therefore, when the operator performs the attaching / detaching operation of the cleaning subunit, the operator is positioned on the near side of the printer 500 shown in FIG. Hereinafter, the front (side) in the above-described direction with respect to the printer 500 shown in FIG.

  FIG. 10 is a rear view showing the rear plate 160 of the subunit holding casing 150. The figure shows the rear plate 160 from the rear side of the subunit holding casing 150. In the present embodiment, the rear side plate 160 is made of an insulating resin.

  As will be described later, in the present embodiment, terminals that receive high voltage are arranged on the rear plate side, while the drive system is placed in front of the cleaning device to transmit drive to each cleaning subunit. With this configuration, it is possible to transfer voltage from the image forming apparatus main body side over a short distance, and the rear side plate is not subjected to a load related to drive transmission, so it is not necessary to ensure the strength, and the resin thickness, etc. Can be simplified.

  The rear plate 160 has a first reservoir receiving hole 162a, a first main positioning pin receiving hole 163a, a first sub positioning pin receiving hole 164a, and a first recovery bias pin receiving hole 166a corresponding to the first cleaning subunit 101. Have. Furthermore, it also has a first cleaning bias pin receiving hole 165a. In addition, the second reservoir receiving hole 162b, the second main positioning pin receiving hole 163b, the second sub positioning pin receiving hole 164b, the second recovery bias pin receiving hole 166b, and the second corresponding to the second cleaning subunit 111 are provided. A cleaning bias pin receiving hole 165b is provided. Further, the third reservoir receiving hole 162c, the third main positioning pin receiving hole 163c, the third sub positioning pin receiving hole 164c, the third recovery bias pin receiving hole 166c, and the third corresponding to the third cleaning subunit 121 are provided. A cleaning bias pin receiving hole 165c is provided. Furthermore, it also has a drive shaft receiving hole 161.

  FIG. 11 is a rear view showing the upper part of the rear plate 160 together with the third cleaning subunit 121. In the drawing, a drive shaft 130 (described later) of the belt cleaning device 100 passes through the drive shaft receiving hole 161 of the rear plate 160. By this penetration, the rear end portion of the drive shaft 130 projects rearward from the rear plate 160, so that the drive transmission system on the printer 500 main body side can be connected to the rear end portion.

  The circular toner storage portion 129 of the third cleaning subunit 121 passes through the third storage portion receiving hole 162c of the rear plate 160. The toner storage portion 129 protrudes in a cylindrical shape from the rear side plate of the third subunit casing 126 of the third cleaning subunit 121. A clearance exists between the inner wall of the third reservoir receiving hole 162c and the toner reservoir 129.

  Since the toner storage portion 129 passes through the third storage portion receiving hole 162c of the rear side plate 160, the following operation can be performed. That is, with the belt cleaning device 100 removed from the printer 500 main body, the toner storage portion 129 screwed into the rear plate of the third subunit casing 126 is rotated and removed from the rear plate, and then the internal waste toner is removed. Is a work to dispose of.

  The third cleaning bias pin 127a of the third cleaning subunit 121 passes through the third cleaning bias pin receiving hole 165c of the rear plate 160. The third cleaning bias pin 127a protrudes rearward from the rear plate of the third subunit casing 126 and is electrically connected to the third cleaning brush roller 122 via a metal bearing (not shown). A clearance exists between the inner wall of the third cleaning bias pin receiving hole 165c and the third cleaning bias pin 127a.

  Since the rear end portion of the third cleaning bias pin 127a passes through the third cleaning bias pin receiving hole 165c, the following is possible. That is, as shown in FIG. 12, the coupling cap 191 provided on the printer 500 main body side is coupled to the rear end portion of the third cleaning bias pin 127a. Then, a cleaning bias is applied from the coupling cap 191 to the third cleaning brush roller 122 through the third cleaning bias pin 127a and a metal bearing (not shown).

  In FIG. 11, the third recovery bias pin 127 b of the third cleaning subunit 121 passes through the third recovery bias pin receiving hole 166 c of the rear plate 160. The third recovery bias pin 127b protrudes rearward from the rear plate of the third subunit casing 126 and is electrically connected to the third recovery roller 123 via a metal bearing (not shown). A clearance exists between the inner wall of the third recovery bias pin receiving hole 166c and the third recovery bias pin 127b.

  Since the rear end portion of the third recovery bias pin 127b penetrates the third recovery bias pin receiving hole 166c, the following is possible. That is, as shown in FIG. 12, the coupling cap 191 provided on the printer 500 main body side is coupled to the rear end portion of the third recovery bias pin 127b. Then, a recovery bias is applied from the coupling cap 191 to the third recovery roller 123 via the third recovery bias pin 127b and a metal bearing (not shown).

  In FIG. 11, the third rear main positioning pin 128 a of the third cleaning subunit 121 is fitted in the third main positioning pin receiving hole 163 c of the rear plate 160. The third rear main positioning pin 128a protrudes from the rear plate of the third subunit casing 126 of the third cleaning subunit 121. There is no clearance between the inner wall of the third main positioning pin receiving hole 163c and the third rear main positioning pin 128a, and both are in close contact with each other. As a result, the rear end portion of the third cleaning subunit 121 is positioned.

  The third rear sub-positioning pin 128b of the third cleaning subunit 121 is fitted in the third sub-positioning pin receiving hole 164c of the rear side plate 160. The third rear sub-positioning pin 128 b projects from the rear plate of the third subunit casing 126 of the third cleaning subunit 121. Of the four upper, lower, left and right inner walls of the third auxiliary positioning pin receiving hole 164c, no clearance exists between the upper and lower inner walls and the third rear auxiliary positioning pin 128b. However, a clearance exists between each of the left and right inner walls and the third rear sub-positioning pin 128b.

  As shown in FIG. 13, the third rear main positioning pin 128a of the third cleaning subunit 121 is tapered. When the third cleaning subunit 121 is mounted, the third cleaning subunit 121 is pushed into the subunit holding casing 150 from the front side of the printer 500 toward the rear side.

  At this time, even if there is a slight misalignment, the tip of the third rear main positioning pin 128a enters the third main positioning pin receiving hole 163c. Thereafter, when the third cleaning subunit 121 is further pushed in, the root portion of the third rear main positioning pin 128a slides on the inner wall of the third main positioning pin receiving hole 163c. The root portion of the third rear main positioning pin 128a comes into close contact with the entire inner wall of the third main positioning pin receiving hole 163c.

  As shown in FIG. 14, the third rear sub-positioning pin 128b of the third cleaning subunit 121 is tapered. When the third cleaning subunit 121 is mounted, the third cleaning subunit 121 is pushed into the subunit holding casing 150 from the front side of the printer 500 toward the rear side.

  At this time, even if there is a slight misalignment, the tip of the third rear auxiliary positioning pin 128b enters the third auxiliary positioning pin receiving hole 164c. Thereafter, when the third cleaning sub-unit 121 is further pushed in, the base portion of the third rear sub-positioning pin 128b slides on the inner wall of the third sub-positioning pin receiving hole 164c. The root portion of the third rear sub-positioning pin 128b comes into contact with the upper and lower inner walls of the third sub-positioning pin receiving hole 164c.

  The positioning of the rear end portion in the longitudinal direction of the third subunit casing 126 is completed at the next timing. That is, the root portion of the third rear main positioning pin 128a is in close contact with the entire inner wall of the third main positioning pin receiving hole 163c, and the root portion of the third rear sub positioning pin 128b is the third sub positioning pin receiving hole 164c. It is the timing which contacted the inner wall. The bottom of the rear end portion of the third subunit casing 126 thus positioned is in a state of floating from the third left support portion 155 and the third right support portion 156 of the subunit holding casing 150.

  In FIG. 11, the third rear main positioning pin 128a is near the third cleaning bias pin 127a to which a high-voltage cleaning bias is applied. For this reason, if the third rear main positioning pin 128a is made of a metal material, there is a possibility of generating a discharge between the third cleaning bias pin 127a and the third rear main positioning pin 128a. Therefore, in the printer 500, the third rear main positioning pin 128a is made of an insulating resin material.

  Although the relationship between the various members at the rear end portion of the third cleaning subunit 121 and the various holes provided in the rear plate 160 has been described, the various members at the rear end portion of the first cleaning subunit 101 and the rear plate 160 are described. The relationship with the various holes provided in is also the same. The relationship between various members at the rear end portion of the second cleaning subunit 111 and various holes provided in the rear plate 160 is also the same.

  FIG. 15 is a perspective view showing the cleaning unit driving unit 19 disposed in the transfer unit 7 together with a part of the third cleaning subunit 121. In the figure, the cleaning unit drive unit 19 includes an output coupling 190, a drive output shaft 192, a drive transmission unit 193 including a timing belt, a drive motor 194, and the like.

  The cleaning unit drive unit 19 is provided on the unit rear side plate of the transfer unit 7. When the drive motor 194 is rotationally driven, the rotational driving force is transmitted to the drive output shaft 192 via the drive transmission unit 193, and the drive output shaft 192 rotates. An output coupling 190 is fixed to the tip of the drive output shaft 192.

  On the other hand, as shown in FIG. 11, in the belt cleaning device 100, the drive shaft 130 is passed through the drive shaft receiving hole 161 of the rear plate 160 of the subunit holding casing 150. This drive shaft 130 passes through the drive shaft receiving hole of the front side plate (“140” in FIG. 16) of the subunit holding casing 150, passes through the inside of the subunit holding casing 150, and then the drive shaft receiving hole of the rear side plate 160. 161 also penetrates. The rear end portion protrudes rearward from the rear side plate 160.

  FIG. 15 shows the rear end portion of the drive shaft 130 protruding in this manner. An input coupling 131 is fixed to the rear end portion as shown in the figure, and is connected to the output coupling 190 of the cleaning unit driving unit 19. Thereby, the rotational driving force of the drive output shaft 192 is transmitted to the drive shaft 130, and the drive shaft 130 rotates.

  FIG. 16 is a partially enlarged perspective view showing the front end portion of the belt cleaning device 100. The front plate 140 of the belt cleaning device 100 rotatably supports the front end portions of the three cleaning subunits (101, 111, 121) and the front end portion of the drive shaft 130, respectively.

  On the front surface of the front plate 140, a first subunit face plate 141a is fixed by a bolt. The first subunit face plate 141a and the front side plate 140 are each provided with a first main positioning pin receiving hole (not shown), and both communicate with each other. The first sub unit face plate 141a and the front side plate 140 are provided with first sub positioning pin receiving holes (not shown), which are in communication with each other.

  On the other hand, a first front main positioning pin 108c and a first front sub positioning pin 108d are projected from the front side plate of the subunit casing of the first cleaning subunit 101. When the first subunit face plate 141a is fixed to the front side plate 140 of the subunit holding casing 150, the front end portion of the first cleaning subunit 101 is positioned as follows.

  That is, the first front sub-positioning pin 108d of the first cleaning sub-unit 101 is fitted into the first sub-positioning pin receiving hole of the front side plate 140 or the first sub unit face plate 141a. At the same time, the first front main positioning pin 108c of the first cleaning subunit 101 is fitted into the first main positioning pin receiving hole of the front side plate 140 or the first subunit face plate 141a. Thereby, positioning is made.

  At the time of positioning, the floor at the front end portion of the subunit casing of the first cleaning subunit 101 corresponds to the first left support portion (151 in FIG. 7) and the first right support portion (152 in FIG. 7) of the subunit holding casing 150. Floating). Prior to this, the floor at the rear end of the subunit casing of the first cleaning sub-unit 101 has already been moved to the first left support (151 in FIG. 7) and the first right support ( It floats from 152) in FIG.

  Therefore, when the first subunit face plate 141a is fixed to the front side plate 140 and the front end portion of the first cleaning subunit 101 is positioned, the entire floor of the subunit casing of the first cleaning subunit 101 becomes the first left support portion. And float from the first right support. In this way, by floating the entire floor of the subunit casing along with the positioning, the subunit casing can be reliably positioned regardless of the dimensional error, extension, deformation, etc. of the subunit casing.

  On the other hand, if positioning is performed with the floor of the subunit casing attached to the support portion, the positioning of the subunit casing becomes unstable due to dimensional error, extension, deformation, etc. of the subunit casing, so that positioning can be performed. It may disappear.

  The first subunit face plate 141a supports a first drive transmission unit 146a including a first recovery gear 142a, a first screw gear 143a, a first cleaning pulley 144a, a first relay pulley gear 145a, and the like. The first recovery gear 142a, the first screw gear 143a, the first cleaning pulley 144a, and the first relay pulley gear 145a are all rotatably supported by the first subunit face plate 141a.

  The first collection gear 142a is connected to the shaft member of the first collection roller 103 (not shown) by a coupling (not shown) on the back side of the first subunit face plate 141a. The first screw gear 143a is connected to a shaft member of the first transport screw 105 (not shown) by a coupling (not shown) on the back side of the first subunit face plate 141a. The first cleaning pulley 144a is connected to the shaft member of the first cleaning brush roller 102 (not shown) by a coupling (not shown) on the back side of the first subunit face plate 141a.

  The first relay pulley gear 145a meshes the gear portion with the first recovery gear 142a. As a result, the rotational driving force of the first relay pulley gear 145a is transmitted to the first recovery gear 142a, and the first recovery roller 103 (not shown) rotates inside the first cleaning subunit 101. Further, when the first recovery gear 142a rotates, the first screw gear 143a meshing with the first recovery gear 142a rotates. As a result, the first transport screw 105 (not shown) rotates inside the first cleaning subunit 101.

  A timing belt is wound around the first relay pulley gear 145a and the first cleaning pulley 144a. As a result, the rotational driving force of the first relay pulley gear 145a is transmitted to the first cleaning pulley 144a, and the first cleaning brush roller 102 (not shown) rotates inside the first cleaning subunit 101.

  Although the positioning of the front end portion in the longitudinal direction of the first cleaning sub-unit 101 has been described, the front end portion of the second cleaning sub-unit 111 and the third cleaning sub-unit 121 is similarly positioned. The first drive transmission unit 146a of the first cleaning subunit 101 has been described, but the same applies to the second drive transmission unit 146b of the second cleaning subunit 111 and the third drive transmission unit 146c of the third cleaning subunit 121. It is the composition of.

  As shown in FIG. 15, the rotational driving force transmitted to the drive shaft 130 behind the belt cleaning device 100 is transmitted to the front of the belt cleaning device 100 by the drive shaft 130 as shown in FIG. 16. Specifically, the front end portion of the drive shaft 130 passes through a through hole provided in the front side plate 140 of the subunit holding casing 150 and projects forward from the front side plate 140.

  An output pulley 1301 is fixed to the front end portion of the drive shaft 130, and a timing belt is wound around the output pulley 1301 and the third relay pulley gear 145c on the third subunit face plate 141c. . Thereby, the rotational driving force of the drive shaft 130 is transmitted to the third relay pulley gear 145c, and various rotary members (for example, the third cleaning brush roller 122) in the third cleaning subunit 121 are rotationally driven.

  A timing belt is also wound around the third cleaning pulley 144c on the third subunit face plate 141c and the second relay pulley gear 145b on the second subunit face plate 141b. Thereby, the rotational driving force of the third cleaning pulley 144c is transmitted to the second relay pulley gear 145b, and various rotary members in the second cleaning subunit 111 are rotationally driven.

  A timing belt is also wound around the second cleaning pulley 144b on the second subunit face plate 141b and the first relay pulley gear 145a on the first subunit face plate 141a. Thereby, the rotational driving force of the second cleaning pulley 144b is transmitted to the first relay pulley gear 145a, and various rotary members in the first cleaning subunit 101 are rotationally driven.

  Thus, in the printer 500, the drive transmission system of the belt cleaning device 100 is concentrated in front of the front side plate 140. On the other hand, behind the rear plate 160, a coupling cap 191 for applying a cleaning bias and a recovery bias from a power source is concentrated. This realizes a layout in which the coupling cap 191 and the bias pin to which a high voltage is applied and the metal rotation shaft of the drive transmission system cannot be brought close to each other, and the occurrence of discharge between them can be avoided. .

  The first cleaning subunit 101 is detached from the subunit holding casing 150 as follows. First, the two timing belts are removed from the first drive transmission portion 146a of the first subunit face plate 141a. Then, the bolts of the first subunit face plate 141 a are loosened, and the first subunit face plate 141 a is removed from the front side plate 140. Then, the subunit removal opening covered by the first subunit unit face plate 141a opens a large opening.

  Next, a hand is put in this subunit removal opening provided in the front side plate 140, and the first cleaning subunit 101 is pulled out from the subunit holding casing 150. When the first cleaning sub-unit 101 is set in the sub-unit holding casing 150, a reverse process to the pulling out process may be performed. Similarly, the second cleaning subunit 111 and the third cleaning subunit 121 can be attached to and detached from the subunit holding casing 150.

  FIG. 17 is a perspective explanatory view of the belt cleaning device 100 in which the front plate 140 shown in FIG. 16 is provided with a reinforcing plate 330, six bearing cases 311 and a front plate handle portion 410. The reinforcing plate 330 is made of metal and is fixed to the front side plate 140 by screw fastening.

  As shown in FIG. 16, the first collection shaft 245 a that is the rotation shaft of the first collection roller 103, the second collection shaft 245 b that is the rotation shaft of the second collection roller 113, and the rotation shaft of the third collection roller 123. The three recovery shafts 245c have a long protruding portion with respect to the front plate 140. Further, the second brush shaft 244 b that is the rotation shaft of the second cleaning brush roller 112, the third brush shaft 244 c that is the rotation shaft of the third cleaning brush roller 122, and the drive shaft 130 also protrude from the front plate 140. The part is long. The protruding portions of these rotating shafts become long because it is necessary to attach a plurality of gears or pulleys to one shaft in order to frustrate the drive system.

  A rotating shaft with a long protruding portion with respect to the front side plate 140 falls under the influence of a gear, a timing belt, etc., and the rotating shaft is shaken by rotating as it is. When the rotating shaft swings by rotating, the rotating shaft is repeatedly deformed and may be damaged by fatigue.

  In the belt cleaning apparatus 100 of the present embodiment, as a configuration for preventing the rotation of the rotating shaft, a reinforcing plate 330 for restricting the movement of the tip of the rotating shaft and six bearing cases 311 are provided. The bearing case 311 is made of non-conductive resin such as ABS (acrylonitrile-butadiene-styrene copolymer) resin, and prevents the rotation shaft from swinging by restricting the movement of the tip of the rotation shaft. Yes.

  Of the six bearing cases 311, the first bearing case 311a restricts the movement of the tip of the drive shaft 130, and the second bearing case 311b restricts the movement of the tip of the third recovery shaft 245c. The third bearing case 311c restricts the movement of the tip of the third brush shaft 244c, and the fourth bearing case 311d restricts the movement of the tip of the second recovery shaft 245b. Further, the fifth bearing case 311e restricts the movement of the tip of the second brush shaft 244b, and the sixth bearing case 311f restricts the movement of the tip of the first recovery shaft 245a.

  FIG. 18 is a cross-sectional view illustrating the relationship between one of the six bearing cases 311 and the reinforcing plate 330. FIG. 1 is a schematic view showing a state in which the bearing portion 310 that supports the rotating shaft 250 is attached to the reinforcing plate 330.

  The six bearing cases 311 have the same configuration except that the positions to be arranged with respect to the reinforcing plate 330 are different. Therefore, in FIGS. 1 and 18, symbols a, b, c, d, e, and Description of f is abbreviate | omitted and the rotating shaft of the object which controls a front-end | tip is described as the rotating shaft 250.

  As shown in FIG. 18, the bearing portion 310 includes a bearing case 311 and a bearing 313 that is a metal ball bearing, and the bearing 313 is press-fitted into the case engaging portion 312 and held in the bearing case 311. Has been.

  As shown in FIGS. 1 and 18, the reinforcing plate 330 is provided with a case through hole 320 through which the case engaging portion 312 of the bearing case 311 passes. As shown in FIG. 1, the case engaging portion 312 is cylindrical and forms a case through hole 320. Furthermore, the outer peripheral diameter (D1 in FIG. 18) of the cylindrical case engaging portion 312 is smaller than the inner peripheral diameter (D2 in FIG. 18) of the case through-hole 320.

  For this reason, when the bearing case 311 is attached to the reinforcing plate 330, a gap is left between the case through-hole 320 and the outer periphery of the case engaging portion 312 as shown in FIG. 1. As a result, the bearing case 311 can be attached to a position that matches the position of the tip of the rotating shaft 250.

  The rotating shaft 250 (130, 245c, 244c, 245b, 244b and 245a) is also supported by the rear side plate 160 and the front side plate 140, and is already supported at two points other than the front end to which the bearing case 311 is attached. For this reason, if the position of the front-end | tip of the rotating shaft 250 is positioned with the bearing case 311, the rotating shaft 250 will be supported by three points.

  In such a configuration, there is no problem if the three points are on an ideal straight line, but if one point is not located on the virtual straight line connecting the other two points, The distortion force works, causing the rotating shaft 250 and the bearing to collide and scrape, causing a problem such as breakage of the member.

  Therefore, in the belt cleaning apparatus 100 according to the present embodiment, the bearing 313 that is a bearing that supports the tip of the rotating shaft 250 does not forcibly position the rotating shaft 250 with respect to the reinforcing plate 330, and the tip of the rotating shaft 250. It can be fixed at a position that matches the position. Thereby, it becomes possible to arrange | position two bearings which support the rotating shaft 250 in the rear side board 160 and the front side board 140, and the bearing 313 on a straight line, and generation | occurrence | production of malfunctions, such as a failure | damage of the member mentioned above, is prevented. be able to.

  The bearing case 311 is fixed to the reinforcing plate 330 by screwing to the reinforcing plate 330 in a state where the bearing 313 is positioned at a position corresponding to the position of the tip of the rotating shaft 250. At this time, the diameter of the hole through which the screw of the bearing case 311 passes is larger than the diameter of the shaft of the screw so that the bearing case 311 can be displaced with respect to the screw hole provided in the reinforcing plate 330. Even if the hole through which the screw of the bearing case 311 passes is larger than the diameter of the shaft of the screw, the bearing case 311 can be fixed to the reinforcing plate 330 by tightening the screw.

  When the screw is tightened, a force in the rotational direction acts on the bearing case 311. If the bearing case 311 rotates about the axis of the screw due to this force, the position of the bearing 313 in accordance with the position of the tip of the rotating shaft 250 will fluctuate, and the above-mentioned members will be damaged. May occur.

  In order to prevent this, when the bearing case 311 is fixed to the reinforcing plate 330, the bearing case 311 is fixed to the reinforcing plate 330 with a contact agent in a state where the bearing 313 aligned with the tip of the rotary shaft 250 is located. To do. As a result, when the screw is tightened, the bearing case 311 can be prevented from rotating and the position of the bearing 313 can be prevented from shifting. Further, by fixing the bearing case 311 to the reinforcing plate 330 by screw fastening, the fixing strength is improved as compared with the case where only the adhesive is fixed, and the rotation of the rotary shaft 250 can be stabilized over a long period of time.

  Further, when no adhesive is used, a rotating force is exerted at the time of screw tightening such that the bearing case 311 rotates in a direction in which the gear provided on the rotating shaft 250 hits another gear that is in contact with the gear. The bearing case 311 is disposed on the surface. In addition, the bearing case 311 is arranged so that a rotating force acts at the time of screw tightening so that the bearing case 311 rotates in a direction opposite to the direction in which the pulley provided on the rotating shaft is pulled by the timing belt. Also good.

  Specifically, when the rotary shaft 250 is the second recovery shaft 245b, the second relay pulley gear 145b provided on the second recovery shaft 245b is moved upward by a timing belt wound around the third cleaning pulley 144c. The force that is pulled up is applied. For this reason, when the fourth bearing case 311d is attached to the second recovery shaft 245b, the fourth bearing case 311d is rotated so that the position where the bearing 313 is provided is directed downward when the fourth bearing case 311d is rotated by screw tightening. A case 311d is arranged.

  As a result, even after the fourth bearing case 311d is attached to the tip of the second recovery shaft 245b and the fourth bearing case 311d is about to rotate by tightening the screw, the timing belt moves the second recovery shaft 245b upward. Pulling force acts. Therefore, when the screw is tightened, the fourth bearing case 311d can be prevented from rotating, and the position of the bearing 313 can be prevented from fluctuating with respect to the tip of the second recovery shaft 245b.

  Here, in the belt cleaning apparatus 100, the voltage applied to the rotating shaft 250 by the power supply may be a high voltage exceeding 1 [kV] in absolute value, specifically a voltage of 10 [kV] at the maximum. Therefore, it is necessary to suppress the occurrence of leak discharge between the rotating shaft 250 and the reinforcing plate 330. Although it is conceivable to electrically float the metal reinforcing plate 330 so that the leak discharge does not occur, it is necessary to electrically ground the reinforcing plate 330 from the viewpoint of safety.

  Therefore, if the reinforcing plate 330 is made of a non-conductive resin, leakage discharge between the rotating shaft 250 and the reinforcing plate 330 can be suppressed. However, since resin is generally inferior in strength to metal, it is necessary to make the thickness of the reinforcing plate 330 thicker than when metal is used, which leads to an increase in the size of the apparatus.

  Therefore, in order to reduce the size of the apparatus, it is necessary to use a metal for the reinforcing plate 330, but the reinforcing plate from the rotating shaft 250 does not generate a leak discharge between the rotating shaft 250 and the reinforcing plate 330. 330 must be spaced apart.

  As a result of experiments by the inventors of the present application, when the voltage applied to the rotating shaft 250 is 10 [kV], reinforcement is performed from the contact position between the bearing 313 and the bearing portion 310 that supports the rotating shaft 250 shown in FIG. When the creepage distance X to the plate 330 was 15 [mm], the leak discharge occurred. The “creeping distance X” is the shortest distance along the surface of the bearing portion 310 from the contact position between the rotating shaft 250 and the bearing portion 310 to the reinforcing plate 330.

  As a result of intensive studies by the inventors of the present application, when the voltage applied to the rotating shaft 250 is Y [kV], the creeping distance X [mm] ≧ voltage Y [kV] × 2 [mm / kV]. It was found that the occurrence of leak discharge can be suppressed by satisfying the above relationship. That is, when the voltage Y applied to the rotating shaft 250 is 10 [kV], the occurrence of the leak discharge can be suppressed by setting the creepage distance X to at least 20 [mm].

The electrical resistance of the bearing case 311 is preferably 10 ¹⁰ [Ω] or more. Thereby, even if a high voltage of 10 [kV] is applied to the rotating shaft 250, the bearing case 311 can function as a non-conductive member.

  Further, as shown in FIG. 1, in the configuration in which the rotating shaft 250 is supported by the bearing 313 and the bearing case 311 that holds the bearing 313 is supported by the reinforcing plate 330, the following condition is further satisfied. do it.

  That is, when the creepage distance from the contact position between the bearing 313 and the bearing case 311 to the reinforcing plate 330 is Z [mm], the creepage distance Z [mm] ≧ voltage Y [kV] × 2 [mm / kV]. To satisfy. That is, when the voltage Y applied to the rotating shaft 250 is 10 [kV], the occurrence of the leak discharge can be suppressed by setting the creeping distance Z to at least 20 [mm].

  The “creeping distance Z” is the shortest distance along the surface of the bearing case 311 from the contact position between the bearing 313 and the bearing case 311 to the reinforcing plate 330 as shown in FIG.

  In the configuration shown in FIG. 1, when the voltage applied to the rotating shaft 250 is 10 [kV], the creepage distance X is 20 [mm] + the diameter of the bearing 313 when the creepage distance Z is 20 [mm]. The direction thickness t (outer diameter−length of inner diameter) [mm] may be used. Thus, the creepage distance X and the creepage distance Z that can suppress the occurrence of the leak discharge, that is, the distance from the rotating shaft 250 to the reinforcing plate 330 are clarified, so that the distance is excessively separated. It is possible to suppress an increase in the size of the apparatus.

  Further, in the belt cleaning device 100 of the present embodiment, the bearing case 311 is configured in such a shape that the creepage distance X and the creepage distance Z satisfy the above-described relationship only by the distance measured along the surface of the bearing case 311. Yes.

  Specifically, the bearing case 311 includes a cylindrical case engaging portion 312 that is a wall portion extending from the axial end portion side of the rotating shaft 250 toward the axial central portion so as to surround the bearing 313. ing. Therefore, by adjusting the length in the rotation axis direction of the case engaging portion 312, the creepage distance X and the creepage distance Z that satisfy the above-described relationships only by the distance along the surface of the bearing case 311, It can be secured easily.

  Further, the bearing case 311 in the surface direction of the reinforcing plate 330 (direction perpendicular to the axial direction of the rotating shaft 250) is greater than when the creepage distance X and the creepage distance Z are ensured by increasing the thickness of the case engaging portion 312. Therefore, the size of the apparatus can be reduced. In the present embodiment, the thickness of the case engaging portion 312 is 1.2 [mm].

  In the printer 500 of the present embodiment, as described above, the terminals that receive the high voltage from the power source are arranged on the rear plate 160 side, while the drive system is placed on the reinforcing plate 330 side to transmit drive to each cleaning subunit. Is going. For this reason, the rear plate 160 that supports the rotating shaft 250 on the back side in the belt cleaning device attaching / detaching direction is made of resin, and only the reinforcing plate 330 that supports the rotating shaft 250 on the near side in the belt cleaning device attaching / detaching direction is made of metal. Thereby, the occurrence of leakage discharge is suppressed on the rear plate 160 side where a high voltage is applied to the terminal, and the strength of the reinforcing plate 330 to which a load related to drive transmission is applied is thinner than that using a resin. Can be secured sufficiently, and the increase in size of the apparatus can be suppressed.

[Modification]
FIG. 19 is a schematic diagram illustrating a state in which the bearing portion 310 that supports the rotating shaft 250 is attached to the reinforcing plate 330 in the belt cleaning device 100 according to the modification.

  In the belt cleaning device 100 according to the modified example, a sliding bearing 314 made of a resin having slidability is used as a bearing member for supporting the rotating shaft 250 of the bearing portion 310 instead of a metal ball bearing such as the bearing 313. Used. Other configurations are the same as those described with reference to FIGS. 1 and 18 and the like, and thus description thereof is omitted.

The bearing portion 310 of the present modification includes a bearing case 311 and a slide bearing 314, and the slide bearing 314 is press-fitted into the case engaging portion 312 and held by the bearing case 311. The electric resistance of the resin constituting the slide bearing 314 is preferably 10 ¹⁰ [Ω] or more. Further, the bearing case 311 and the plain bearing 314 may be integrally formed to form the bearing portion 310.

  As shown in FIG. 19, in the configuration in which the rotating shaft 250 is supported by the slide bearing 314 and the bearing case 311 that holds the slide bearing 314 is supported by the reinforcing plate 330, the following condition is satisfied. Thus, the occurrence of the leak discharge can be suppressed.

  That is, when the creepage distance from the contact position between the rotary shaft 250 and the plain bearing 314 to the reinforcing plate 330 is X [mm] and the voltage applied to the rotary shaft 250 is Y [kV], the creepage distance X [mm] ] ≧ voltage Y [kV] × 2 [mm / kV] may be satisfied.

  Note that the “creeping distance X” in the present modification is from the contact position between the rotary shaft 250 and the slide bearing 314 to the reinforcing plate 330 passing through the surfaces of the slide bearing 314 and the bearing case 311 as shown in FIG. Is the shortest distance.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A cleaning member such as a first cleaning brush roller 102 provided to be rotatable about a rotation shaft that removes toner on a member to be cleaned such as the intermediate transfer belt 8 and a power source that applies a voltage to the rotation shaft of the cleaning member In a cleaning device such as a belt cleaning device 100 including a voltage applying unit such as a support member that supports the rotating shaft, the support member includes a non-conductive bearing portion that supports the rotating shaft; A bearing support portion such as a metal reinforcing plate 330 that supports the bearing portion, and the shortest distance along the surface of the support member from the contact position between the rotating shaft and the bearing portion to the bearing support portion. X [mm] ≧ Y [kV] × where the creepage distance is X [mm] and the voltage applied to the rotating shaft by the voltage applying means is Y [kV]. Satisfy the relationship of [mm / kV].
The degree to which the bearing support portion should be separated from the rotating shaft has been determined empirically and there is no definite standard, and the optimum value has not been clearly clarified. Therefore, as a result of extensive research conducted by the inventor of the present application, by satisfying the above-described relationship of X [mm] ≧ Y [kV] × 2 [mm / kV], part of the support member from the rotating shaft of the cleaning member. It has been found that the occurrence of leakage discharge to the metal bearing support that constitutes can be suppressed. In addition, by clarifying the distance between the rotating shaft and the bearing support portion so that the occurrence of leak discharge from the rotating shaft to the bearing support portion can be suppressed, the distance is separated more than necessary. Therefore, it is possible to suppress an increase in the size of the apparatus.
(Aspect B)
In (Aspect A), the bearing portion is provided with a bearing member such as a bearing 313 that pivotally supports the rotating shaft, and a bearing holding member such as a bearing case 311 that holds the bearing member. The bearing holding member is made of resin. According to this, as described in the above embodiment, the occurrence of the leak discharge can be suppressed by forming the bearing holding member into a shape that can provide the creepage distance that satisfies the relationship.
(Aspect C)
In (Aspect B), the bearing holding member has a shape such that the creepage distance satisfies the relationship only by a distance measured along the surface of the bearing holding member. According to this, as described in the above embodiment, the creepage distance that satisfies the relationship can be easily obtained by adjusting the shape of the bearing holding member.
(Aspect D)
In (Aspect B) or (Aspect C), the bearing holding member is in contact with the bearing member that extends from the axial end to the axial center so as to surround the bearing member. It has a wall part such as a joint part 312. According to this, as described in the above embodiment, by adjusting the length of the wall portion of the bearing holding member in the rotation axis direction, the creeping distance that easily satisfies the relationship can be ensured. it can.
(Aspect E)
In (Aspect B), (Aspect C), or (Aspect D), the bearing member has conductivity, and the support member from the contact position between the bearing member and the bearing holding member to the bearing support portion When the creepage distance that is the shortest distance along the surface is Z [mm] and the voltage applied to the rotating shaft by the voltage applying means is Y [kV], Z [mm] ≧ Y [kV] × 2 [mm / kV] is satisfied. According to this, as described in the above embodiment, the occurrence of the leak discharge can be suppressed.
(Aspect F)
In (Aspect B), (Aspect C), (Aspect D) or (Aspect E), the electric resistance of the bearing holding member is 10 ¹⁰ [Ω] or more. According to this, as described in the above embodiment, it is possible to suppress the occurrence of the leak discharge more reliably.
(Aspect G)
In (Aspect A), (Aspect B), (Aspect C), (Aspect D), (Aspect E) or (Aspect F), the maximum voltage applied to the rotating shaft by the voltage applying means is an absolute value. 10 [kV]. According to this, as described in the above embodiment, the occurrence of the leak discharge can be suppressed even when a high voltage is applied to the rotating shaft.
(Aspect H)
In (Aspect A), (Aspect B), (Aspect C), (Aspect D), (Aspect E), (Aspect F), or (Aspect G), three cleaning members are provided, and the toner is normally charged. A first cleaning member such as a first cleaning brush roller 102 that electrostatically removes toner having a polarity opposite to the normal charging polarity on the object to be cleaned by applying a voltage having the same polarity as the polarity; and the first cleaning The first member is disposed downstream of the member in the moving direction of the surface of the object to be cleaned, and a voltage having a polarity opposite to the normal charge polarity of the toner is applied to electrostatically remove the toner of the normal charge polarity on the object to be cleaned. A second cleaning member such as a second cleaning brush roller 112 and a second cleaning member disposed downstream of the second cleaning member in the moving direction of the surface of the object to be cleaned; Has a third cleaning member such as a third cleaning brush roller 122 to remove the toner of the normal charging polarity on 掃体 electrostatically, a. According to this, as described in the above embodiment, it is possible to suppress the occurrence of the leak discharge while improving the cleaning performance.
(Aspect I)
An image carrier that carries a toner image, a toner image forming unit that forms a toner image on the surface of the image carrier, a transfer unit that transfers the toner image formed on the surface of the image carrier to a transfer member, In the image forming apparatus provided with a cleaning device that scrapes off the toner that is attached to the surface of the image carrier and cleans the surface, the cleaning device includes (Aspect A), (Aspect B), The cleaning device of (Aspect C), (Aspect D), (Aspect E), (Aspect F), (Aspect G) or (Aspect H) was used. According to this, as described in the above embodiment, it is possible to suppress the occurrence of leak discharge and achieve good image formation while reducing the size of the apparatus.
(Aspect J)
In (Aspect I), the cleaning unit is detachable from the main body of the image forming apparatus, and the cleaning unit applies the voltage applying unit to a voltage-supplied supply unit such as the terminal provided on the rear side in the cleaning unit attaching / detaching direction. From the drive source such as the drive motor 194 provided in the main body of the image forming apparatus by one drive input unit such as the input coupling 131 on the back side in the direction of attaching / detaching the cleaning unit. Drive is transmitted to the front side of the cleaning means attaching / detaching direction by a drive transmission means such as a drive shaft 130, and the cleaning member is driven on the front side of the cleaning means attaching / detaching direction, and the metal bearing support portion is cleaned with the cleaning means. It was provided only on the front side in the attaching / detaching direction. According to this, as described in the above embodiment, it is possible to suppress the occurrence of leak discharge while downsizing the apparatus.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 4 Drum cleaning device 5 Developing device 6 Process unit 7 Transfer unit 8 Intermediate transfer belt 9 Primary transfer roller 10 Driven roller 11 Drive roller 12 Secondary transfer counter roller 13 Cleaning counter roller 16 Tension roller 17 Application brush counter Roller 18 Secondary transfer roller 19 Cleaning unit drive unit 90 Optical sensor unit 91 Optical sensor 100 Belt cleaning device 101 First cleaning subunit 102 First cleaning brush roller 103 First recovery roller 104 First scraping blade blade 105 First transport Screw 106 First subunit casing 108c Pin 108d Pin 111 Second cleaning subunit 112 Second cleaning brush roller 113 First Collection roller 114 Second scraping blade blade 115 Second transport screw 116 Second subunit casing 121 Third cleaning subunit 122 Third cleaning brush roller 123 Third recovery roller 124 Third scraping blade blade 125 Third transport screw 126 Third subunit casing 127a Third cleaning bias pin 127b Third recovery bias pin 128a pin 128b pin 129 Toner storage portion 130 Drive shaft 131 Input coupling 140 Front side plate 141a First subunit face plate 141b Second subunit face plate 141c Third subunit face plate 142a First recovery gear 143a First screw gear 144a First cleaning pulley 144b Second cleaning pulley -144c Third cleaning pulley 145a First relay pulley gear 145b Second relay pulley gear 145c Third relay pulley gear 146a First drive transmission section 146b Second drive transmission section 146c Third drive transmission section 150 Subunit holding casing 151 First left support section 152 1st right support part 153 2nd left support part 154 2nd right support part 155 3rd left support part 156 3rd right support part 160 Rear side plate 161 Drive shaft receiving hole 162a 1st storage part receiving hole 162b 2nd storage part Receiving hole 162c Third reservoir receiving hole 163a Pin receiving hole 163b Pin receiving hole 163c Pin receiving hole 164a Pin receiving hole 164b Pin receiving hole 164c Pin receiving hole 165a First cleaning bias pin receiving hole 165b Second cleaning bias pin receiving hole 165 c Third cleaning bias pin receiving hole 166a First recovery bias pin receiving hole 166b Second recovery bias pin receiving hole 166c Third recovery bias pin receiving hole 171 First insulating seal member 172 Second insulating seal member 173 Third insulation Seal member 174 inlet seal 190 output coupling 191 coupling cap 192 drive output shaft 193 drive transmission unit 194 drive motor 200 lubricant application device 201 application brush roller 202 solid lubricant 244b second brush shaft 244c third brush shaft 245a first Recovery shaft 245b Second recovery shaft 245c Third recovery shaft 250 Rotating shaft 310 Bearing portion 311 Bearing case 311a First bearing case 311b Second bearing case 311c Third bearing case 311d Fourth bearing case 311e Fifth bearing case 311f Sixth bearing case 312 Case engaging portion 313 Bearing 320 Case through-hole 330 Reinforcing plate 410 Front plate handle 500 Printer 1301 Output pulley

JP 2009-258541 A

Claims (10)

A cleaning member provided to be rotatable about a rotation shaft, which removes toner on a member to be cleaned;
Voltage applying means for applying a voltage to the rotating shaft of the cleaning member;
In a cleaning device comprising a support member that supports the rotating shaft,
The support member includes a non-conductive bearing portion that supports the rotating shaft, and a metal bearing support portion that supports the bearing portion,
A creepage distance that is the shortest distance along the surface of the support member from the contact position between the rotation shaft and the bearing portion to the bearing support portion is X [mm], and is applied to the rotation shaft by the voltage application means. A cleaning device characterized by satisfying a relationship of X [mm] ≧ Y [kV] × 2 [mm / kV] where Y [kV] is a voltage to be applied. The cleaning device according to claim 1,
The bearing portion is provided with a bearing member that rotatably supports the rotating shaft, and a bearing holding member that holds the bearing member,
At least the bearing holding member is made of resin. The cleaning device according to claim 2, wherein
The cleaning device, wherein the bearing holding member has a shape such that the creepage distance satisfies the relationship only by a distance measured along a surface of the bearing holding member. The cleaning device according to claim 2 or 3,
The said bearing holding member has a wall part which contact | connects this bearing member extended toward the axial direction center side from the axial direction edge part side of the said rotating shaft so that the said bearing member might be surrounded. The cleaning device according to claim 2, 3 or 4,
The bearing member has electrical conductivity;
A creepage distance that is the shortest distance along the surface of the support member from the contact position between the bearing member and the bearing holding member to the bearing support portion is Z [mm], and is applied to the rotating shaft by the voltage applying means. A cleaning device characterized by satisfying a relationship of Z [mm] ≧ Y [kV] × 2 [mm / kV], where Y [kV] is a voltage to be applied. The cleaning device according to claim 2, 3, 3, 4 or 5.
An electrical resistance of the bearing holding member is 10 ¹⁰ [Ω] or more. The cleaning device according to claim 1, 2, 3, 4, 5 or 6.
A cleaning device, wherein the maximum voltage applied to the rotating shaft by the voltage applying means is 10 [kV] in absolute value. The cleaning device according to claim 1, 2, 3, 4, 5, 6 or 7.
Including three cleaning members,
A first cleaning member that is applied with a voltage having the same polarity as the normal charging polarity of the toner and electrostatically removes toner having a polarity opposite to the normal charging polarity on the object to be cleaned;
It is disposed downstream of the first cleaning member in the moving direction of the surface of the cleaning object, and a voltage having a polarity opposite to the normal charging polarity of the toner is applied to electrostatically discharge the toner of the normal charging polarity on the cleaning object. A second cleaning member to be removed,
It is disposed downstream of the second cleaning member in the moving direction of the surface of the cleaning object, and a voltage having a polarity opposite to the normal charging polarity of the toner is applied to electrostatically charge the toner of the normal charging polarity on the cleaning object. And a third cleaning member to be removed. An image carrier for carrying a toner image;
Toner image forming means for forming a toner image on the surface of the image carrier;
Transfer means for transferring the toner image formed on the surface of the image carrier to a transfer member;
In an image forming apparatus comprising: a cleaning unit that scrapes off the toner that is attached to the surface of the image carrier to clean the surface.
An image forming apparatus using the cleaning device according to claim 1, 2, 3, 4, 5, 6, 7, or 8 as the cleaning unit. The image forming apparatus according to claim 9.
The cleaning means is detachable from the image forming apparatus main body,
The cleaning unit is supplied with a voltage from the voltage applying unit to a voltage supply unit provided on the back side in the cleaning unit attaching / detaching direction, and the image forming apparatus is configured with one drive input unit on the back side in the cleaning unit attaching / detaching direction. It is configured to receive drive from a drive source provided in the main body, transmit the drive to the front side of the cleaning means attaching / detaching direction by the drive transmission means, and drive the cleaning member on the near side of the cleaning means attaching / detaching direction,
An image forming apparatus, wherein the metal bearing support portion is provided only on the front side in the direction of attaching / detaching the cleaning means.

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