JP2011191624A - Cleaning device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device capable of suppressing uneven abrasion of a recovery member and a scratching member, and an image forming apparatus. <P>SOLUTION: When a reverse charge toner recovery roller 105 rotates, a cam plate 116 attached to the shaft of the reverse charge toner recovery roller 105 rotates, and scratching blades 103, 106, and 109 reciprocate in the axial direction of recovery rollers 102, 105, and 108. This changes the places of the scratching blades which side into contact with the surfaces of the recovery rollers in the axial direction. Thus, parts of the recovery rollers having high circumferential average hardness are prevented from always sliding into contact with soft parts of the scratching blades, and parts of the recovery rollers having low circumferential average hardness are prevented from always sliding into contact with hard parts of the scratching parts. Thus, uneven abrasion of the recovery rollers and the scratching blades is suppressed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  As a cleaning device used in image forming apparatuses such as copying machines, facsimile machines, printers, etc., the cleaning blade made of an elastic member is pressed against the peripheral surface of the image carrier that is the object to be cleaned, and the toner on the image carrier is scraped off. There is known a blade cleaning method for removing them. The blade cleaning method is widely used because of its simple structure and stable performance.

  In recent years, there has been an increasing demand for image quality improvement, and in order to meet the demand, toner particle size reduction and spheroidization have been promoted. By reducing the particle size, it is possible to obtain a high-definition image with higher accuracy and fineness, and by improving the spherical shape, it is possible to improve developability and transferability.

  However, in the case of using a toner having a small particle size and a spherical shape, it is difficult to perform good cleaning with a general cleaning blade method. This is for the reason described below. That is, the cleaning blade removes the toner while rubbing the surface of the image carrier, but the edge of the cleaning blade is deformed by the frictional resistance with the image carrier, so-called stick slip. A minute space is formed between the blades. The smaller the toner with a smaller particle size, the easier it is to enter this space, and the closer the toner that has entered the shape of a sphere is, the more likely the toner will rotate and the more easily it will roll in this space. For this reason, the toner whose particle size has been reduced and spheroidized is likely to push up the cleaning blade and easily slip into the space between the cleaning blade and the image carrier.

  In the case of using a toner having a small particle size and a spherical shape, it is conceivable that the pressing force (linear pressure) of the cleaning blade against the image carrier is increased to prevent the toner from being trapped. However, if the pressing force is increased and a high load is applied, the wear of the image carrier and the cleaning blade advances, and the service life becomes extremely short. In recent years, since the life of the apparatus is required to be extended, such a problem related to durability must be avoided.

  If the electrostatic cleaning method is employed as in the cleaning device described in Patent Document 1, it is possible to satisfactorily clean even the toner produced by the polymerization method. Specifically, the cleaning device described in Patent Literature 1 includes a cleaning brush that rotates while contacting an image carrier that is a cleaning target, a collection roller that rotates while contacting the cleaning brush, and a scraping that contacts the collection roller. And a blade. A cleaning voltage having a polarity opposite to the normal charging polarity of the toner is applied to the cleaning brush. A recovery voltage having the same polarity as the cleaning voltage and a value larger than the cleaning voltage is applied to the recovery roller. The transfer residual toner, which is an adhering matter adhering to the surface of the image carrier, is electrostatically transferred from the belt surface to the brush by the cleaning voltage while being scratched by the brush of the cleaning brush. Thereafter, after electrostatic transfer from the cleaning brush to the collecting roller, the scraping blade scrapes off the surface of the collecting roller. Since the toner is close to a sphere and has a small diameter, even a toner produced by a polymerization method that is difficult to clean with a cleaning blade can be satisfactorily removed from the surface of the image carrier by electrostatic transfer.

  As the collection roller, a metal roller is adopted because it is a conductive material that is difficult to wear. Further, as the scraping blade, a metal blade is employed as a material that does not turn up without a lubricant and has little wear.

  However, when a metal roller is used as the recovery roller and a metal blade is used as the scraping blade, the metal blade and the surface of the recovery roller may wear unevenly. When uneven wear occurs, powder such as toner and brush powder enters the unevenly worn portion, and these powders become a grindstone material, further accelerating the progress of uneven wear. Finally, the toner on the surface of the collecting roller cannot be satisfactorily scraped by the scraping blade, resulting in scraping failure. Thus, when scraping failure occurs in the collecting roller, toner does not adhere to the portion where the scraping failure of the collecting roller occurs, and the toner collecting capability of the collecting roller is reduced. As a result, uncollected toner that is not collected by the collecting roller on the cleaning brush and remains on the cleaning brush increases, and eventually the amount of toner that adheres to the cleaning brush decreases, resulting in poor cleaning.

  Therefore, as a result of intensive studies on the reason why the metal blade and the surface of the collecting roller are worn unevenly, the present inventors have found the following. That is, the metal blade has a strong portion and a weak portion of the metal structure, a strong portion of the metal structure is hard, and a weak portion of the metal structure is soft. As a result, the hardness of the scraping member is different at each position in the axial direction. Further, it was found that the surface of the metal roller has a hard part and a soft part for the same reason as described above. As a result, the average hardness of the collection roller surface in the circumferential direction of the collection roller is different at each position in the axial direction. For this reason, if the portion of the collecting roller whose average hardness in the circumferential direction is rubbed against the soft portion of the scraping blade, the scraping blade is unevenly worn, and the portion of the collecting roller whose average hardness in the circumferential direction is soft It has been found that when the scraping blade is rubbed against the hard part, uneven wear occurs on the surface of the collecting roller.

  The present invention has been made in view of the above background, and an object thereof is to provide a cleaning device and an image forming apparatus capable of suppressing uneven wear of the recovery member and the scraping member.

In order to achieve the above object, the invention according to claim 1 is a surface-movable cleaning member that electrostatically moves and removes toner on a surface-moving member to its own surface, and the cleaning member on the cleaning member. Cleaning device comprising: a surface-movable recovery member that electrostatically moves the toner to its surface and recovers; and a scraping member that scrapes the toner on the recovery member by rubbing against the surface of the recovery member. The apparatus is characterized in that a moving means for reciprocally moving the recovery member relative to the scraping member in the recovery member axial direction is provided.
According to a second aspect of the present invention, in the cleaning device of the first aspect, the recovery member and the scraping member are made of a metal material.
According to a third aspect of the present invention, in the cleaning device according to the first or second aspect, a normally charged toner cleaning member that removes a normally charged toner charged to a normally charged polarity of the toner on the member to be cleaned, and the normally charged toner A regular charged toner cleaning unit comprising a regular charged toner collecting member for collecting regular charged toner adhering to the cleaning member; and a regular charged toner scraping member for scraping the regular charged toner of the regular charged toner collecting member; A reversely charged toner cleaning member that removes the reversely charged toner charged to a polarity opposite to the normal charge polarity of the toner on the cleaning body; and a reversely charged toner recovery member that recovers the reversely charged toner attached to the reversely charged toner cleaning member; A reversely charged toner provided with a reversely charged toner scraping member for scraping the reversely charged toner of the reversely charged toner collecting member A cleaning section, and the moving means reciprocates the regular charged toner collecting member in the axial direction of the regular charged toner collecting member relative to the regular charged toner scraping member, and the reverse The charged toner collecting member is reciprocally moved in the axial direction of the reversely charged toner collecting member relative to the reversely charged toner scraping member.
According to a fourth aspect of the present invention, in the cleaning device of the third aspect, the moving means is configured to reciprocate in the axial direction of the regular charged toner collecting member relative to the regular charged toner scraping member of the regular charged toner collecting member. The phase of the movement and the reciprocal movement of the reversely charged toner collecting member relative to the reversely charged toner scraping member relative to the reversely charged toner scraping member are different from each other.
According to a fifth aspect of the present invention, in the cleaning apparatus according to the first to fourth aspects, the moving means is reciprocally moved using a cam mechanism.
According to a sixth aspect of the present invention, there is provided an image forming apparatus for forming an image on a recording material by transferring a toner image formed on the image bearing member from the image bearing member to a recording material. The cleaning device according to any one of claims 1 to 5 is used as a cleaning device for cleaning residual toner remaining on the image carrier after transfer.
According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect, a toner having a shape factor SF1 of 100 to 150 and an average particle diameter of 6 μm or less is used as the toner. .

  According to the present invention, when the recovery member is reciprocated relative to the scraping member in the axial direction of the recovery member, the portion of the recovery member having a hard average hardness in the surface movement direction is soft to the scraping member. It is possible to suppress rubbing with the part at all times, and to suppress uneven wear of the scraping member. Moreover, it can suppress that the part whose average hardness of the surface movement direction of a collection | recovery member always rubs with the hard part of a scraping member, and can suppress the uneven wear of a collection | recovery member.

1 is a schematic configuration diagram illustrating a main part of a printer according to an embodiment. FIG. 3 is an enlarged schematic configuration diagram in the vicinity of an intermediate transfer belt showing a gradation pattern and an optical sensor. FIG. 3 is an enlarged schematic view showing a chevron patch formed on the intermediate transfer belt. FIG. 2 is an enlarged configuration diagram illustrating a belt cleaning device of the printer and its surroundings in an enlarged manner. The schematic block diagram which shows a belt cleaning apparatus and a moving mechanism. AA sectional drawing of FIG. The figure explaining the reciprocating motion of each scraping blade. The conceptual diagram when the scraping blade after verification experiment is observed from the front end surface direction. The figure which shows the measurement result of the roughness of the collection | recovery roller surface. The principal part schematic block diagram of the belt cleaning apparatus of the modification 1. FIG. The principal part schematic block diagram of the belt cleaning apparatus of the modification 2. FIG. FIG. 6 is a schematic diagram illustrating a maximum diameter MXLNG and a planar area AREA of a projected image with respect to a two-dimensional plane of toner particles. FIG. 4 is a schematic diagram for explaining a peripheral length PERI and a flat area AREA of a projected image with respect to a two-dimensional plane of toner particles. (A), (b), (c) is a figure which shows the shape of a toner typically, respectively. FIG. 2 is a schematic configuration diagram illustrating a main part of a tandem direct transfer type printer. 1 is a schematic configuration diagram showing a main part of a monochrome printer.

  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) will be described. First, the basic configuration of the printer will be described. FIG. 1 is a schematic configuration diagram showing a main part of the printer. The printer 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. 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 is disposed as a belt device including an endless intermediate transfer belt 8 that is a belt member. 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 drive roller 11, a secondary transfer counter roller 12, three cleaning counter rollers 13, 14, 15 and an application brush opposing 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 in the drawing by the rotation of the driving roller 11 that is driven to rotate clockwise 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. 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). The paper transfer belt is bridged by the secondary transfer roller, several supporting rollers, and a driving roller, and the intermediate transfer belt 8 and the paper transfer belt are placed between the secondary transfer roller 18 and the secondary transfer counter roller 12. It is good also as a structure inserted | pinched.

  Also, the three cleaning counter rollers 13, 14, and 15 disposed inside the belt loop are intermediate transfer belts between the cleaning brush rollers 101, 104, and 107 of the belt cleaning device 100 disposed outside the belt loop. 8 is sandwiched. As a result, a cleaning nip is formed in which the front surface of the intermediate transfer belt 8 and the cleaning brush rollers 101, 104, and 107 come into contact with each other. The belt cleaning device 100 can be integrally replaced with the intermediate transfer belt 8. However, when the belt cleaning device 100 and the intermediate transfer belt 8 have different life settings, the belt cleaning device 100 is replaced with the intermediate transfer belt 8. May be independently detachable from the printer body. Details of the belt cleaning apparatus 100 will be described later.

  The printer includes a paper feed unit (not shown) having a paper feed cassette for storing the recording paper P and a paper feed roller for feeding the recording paper P from the paper feed cassette to the paper feed path. 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 present printer, an elastic layer having 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 this printer, 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 series) , Polyolefins, polyvinyl chlorides, polyurethanes, polyamides, polyureas, polyesters, fluororesins) and the like can be used. However, it is not limited to the said material.

  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 differs depending on the layer thickness of the intermediate transfer belt 8, if the hardness is lower than 10 ° JIS-A, transfer deficiency tends 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 the said material.

  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, the woven fabric can be any woven fabric such as knitted weave, and of course, a woven fabric that has been woven can also be used and can be subjected to a conductive treatment.

  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 of polyurethane, polyester, epoxy resin, etc., or a material that reduces surface energy and increases lubricity, such as fluororesin, fluorine compound, fluorocarbon, titanium oxide, silicon carbide, etc. One type or two or more types, or those having different particle sizes as required can be dispersed and used. 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 the said material.

  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 a 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.

  When image information is sent from a personal computer or the like, the printer 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 feed unit (not shown), the recording paper P is sent out from the paper feed cassette one by one by the paper feed 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 the full-color image is conveyed from the secondary transfer nip to a fixing device and subjected to a toner image fixing process.

  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.

  An optical sensor unit 150 is disposed on the right side of the K process unit 6K in the drawing so as to face the front surface of the intermediate transfer belt 8 with a predetermined gap. As shown in FIG. 2, the optical sensor unit 150 includes a Y optical sensor 151Y, a C optical sensor 151C, an M optical sensor 151M, and a K optical sensor 151K 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. .

In this printer, image density control for optimizing the image density of each color is executed when the power is turned on or every time a predetermined number of prints are performed.
In the image density control, first, gradation patterns Sk, Sm, Sc, and Sy of each color are automatically formed on the intermediate transfer belt 8 at positions facing the optical sensors 151Y, M, C, and K as shown in FIG. 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, M, C, and K. 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 151 as the intermediate transfer belt 8 moves endlessly. At this time, the optical sensor 151 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, the adhesion amount of each color toner pattern in each toner patch is calculated from the output voltage of the optical sensor 151 when each color toner patch is detected and the adhesion amount conversion algorithm, 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 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 amount correction process, Y, M, C, and K color toner images called chevron patches PV as shown in FIG. 3 are respectively provided at one end and the other end in the width direction of the intermediate transfer belt 8. An image for color misregistration detection is formed. As shown in FIG. 3, the chevron patch PV has a predetermined pitch in the belt moving direction, which is the sub-scanning direction, with the toner images of each color of Y, M, C, and K inclined by about 45 ° from the main scanning direction. Is a line pattern group arranged in. The amount of the chevron patch PV attached is about 0.3 [mg / cm ² ].

  By detecting each color toner image in the chevron patch PV formed at both ends in the width direction of the intermediate transfer belt 8, the position of each color toner image in the main scanning direction (photoconductor axial direction), the sub-scanning direction (belt movement) Direction) position, magnification error in the main scanning direction, and skew from the main scanning direction. The main scanning direction here refers to the 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 151 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, on the basis of the amount of registration deviation, the optical writing start timing for the photosensitive member 1 is corrected every other polygon mirror surface of the optical writing unit (not shown), that is, one scanning line pitch as one unit, and each color is corrected. To reduce the registration error of the toner image. 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 for a long time increases, so that the toner charging characteristics deteriorate and the image quality deteriorates when used for image formation (development capability decreases, 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 amount of each developing device 5Y, M, C, K and the operation time of each developing device 5Y, M, C, K, and at a predetermined timing, the developing device. Whether or not the toner consumption amount is equal to or less than the threshold value for the operation time of the predetermined period is checked for each developing device, and the refresh mode is executed for the developing device equal to or less than the threshold value.

When the refresh mode is executed, a toner consumption pattern is created in a non-image forming area corresponding to the space between the sheets of the photoconductor 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 may be about 1.0 [mg / cm ² ]. Further, when the toner Q / d distribution of the toner consumption pattern transferred to the intermediate transfer belt 8 is measured, it is almost aligned with the normal charging polarity.

  Each color gradation pattern, chevron patch, and toner consumption pattern formed on the intermediate transfer belt 8 are collected by the belt cleaning device 100. At this time, the belt cleaning device 100 must remove a large amount of toner from the intermediate transfer belt 8. However, in a conventional cleaning device including a polarity control unit and a brush roller, or a cleaning device including a brush roller that removes positive polarity toner and a brush roller that removes negative polarity toner, each color gradation pattern, Untransferred toner images such as chevron patches and toner consumption patterns could not be removed at once. In such a case, the toner on the intermediate transfer belt 8 that could not be cleaned may be transferred onto the recording paper during the next printing operation, resulting in an abnormal image.

  Therefore, the belt cleaning apparatus 100 of the printer is configured such that untransferred toner images such as each color gradation pattern, chevron patch, and toner consumption pattern can be removed at a time.

  The toner on the intermediate transfer belt is transferred to the recording paper by receiving a transfer electric field having a polarity opposite to the normal charge polarity of the toner (positive polarity). There is something to be. The amount of charge of the transfer residual toner is shifted to the positive polarity side by receiving positive charge injection applied at the secondary transfer portion. For this reason, the transfer residual toner on the intermediate transfer belt has a broad charge distribution in which a positive polarity toner and a negative polarity toner are mixed.

  Therefore, the belt cleaning apparatus of the present embodiment includes a normal charging toner cleaning unit that electrostatically removes normal charging toner toner of normal charging charge polarity (negative polarity) on the intermediate transfer belt, and normal charging on the intermediate transfer belt. A reversely charged toner cleaning unit that electrostatically removes toner of a polarity opposite to that of the polarity (positive polarity), and a precharger that electrostatically removes toner of normal charge polarity with respect to the surface movement direction of the intermediate transfer belt. A cleaning unit is provided.

FIG. 4 is an enlarged configuration diagram showing the belt cleaning device 100 and its surroundings, which are characteristic points of the printer, in an enlarged manner.
In the figure, a belt cleaning device 100 includes a pre-cleaning unit 100a for roughly removing an untransferred toner image on the intermediate transfer belt 8, and a polarity opposite to a normal charging polarity (negative polarity) on the intermediate transfer belt 8. A reversely charged toner cleaning unit 100b that removes the toner charged to (positive polarity) and a regular charged toner cleaning unit 100c that removes the toner charged to the regular charge polarity on the intermediate transfer belt 8 are provided.

  The pre-cleaning unit 100a has a pre-cleaning brush roller 101 as a pre-cleaning member. Further, a pre-collecting roller 102 as a pre-collecting member that collects toner attached to the pre-cleaning brush roller 101, and a pre-scraping blade 103 as a pre-scraping member that contacts the pre-collecting roller 102 and scrapes the toner from the roller surface. have.

  Since most of the toner constituting the untransferred toner image is charged with a normal charging polarity (negative polarity), a voltage having a polarity (positive polarity) opposite to the normal charging polarity is applied to the pre-cleaning brush roller 101, The negative toner on the intermediate transfer belt 8 is electrostatically removed. Further, a positive polarity voltage larger than that of the pre-cleaning brush roller 101 is applied to the pre-collection roller 102. In the belt cleaning apparatus 100, the voltage applied to the pre-cleaning brush roller 101 is set so that 90% of the untransferred toner image is removed by the pre-cleaning brush roller 101.

  In addition, the pre-cleaning unit 100a includes a transport screw 110 as a transport unit for transporting to a waste toner tank (not shown) provided in the image forming apparatus main body.

  The reversely charged toner cleaning unit 100b is disposed downstream of the precleaning unit 100a in the moving direction of the intermediate transfer belt 8, and electrostatically charges toner charged to a polarity (positive polarity) opposite to the normal charging polarity (negative polarity) of the toner. And a reversely charged toner cleaning brush roller 104 as a reversely charged toner cleaning member to be removed. Further, the reversely charged toner collecting roller 105 as a reversely charged toner collecting member for collecting the reversely charged toner attached to the reversely charged toner cleaning brush roller 104, and abutting against the reversely charged toner collecting roller 105 and scraping the reversely charged toner from the roller surface. A reversely charged toner scraping blade 106 is provided as a reversely charged toner scraping member. A negative voltage is applied to the reversely charged toner cleaning brush roller 104, and a negative voltage greater than that of the reversely charged toner cleaning brush roller 104 is applied to the reversely charged toner recovery roller 105. Further, the reversely charged toner cleaning unit 100b applies a negative charge to the toner on the intermediate transfer belt 8 so that the charge polarity of the toner on the intermediate transfer belt 8 is aligned with the normal charge polarity (negative polarity). It also has a function as a control means.

  The normally charged toner cleaning unit 100c is disposed downstream of the reversely charged toner cleaning unit 100b in the moving direction of the intermediate transfer belt 8, and is normally charged as a normally charged toner cleaning member that electrostatically removes toner charged to the normally charged polarity. A toner cleaning brush roller 107 is provided. Further, the regular charged toner collecting roller 108 as a regular charged toner collecting member for collecting the regular charged toner attached to the regular charged toner cleaning brush roller 107 and the regular charged toner collecting roller 108 are abutted and scraped from the roller surface. A regular charged toner scraping blade 109 is provided as a regular charged toner scraping member. A positive voltage is applied to the normally charged toner cleaning brush roller 107, and a positive voltage greater than that of the normally charged toner cleaning brush roller 107 is applied to the normally charged toner recovery roller 108.

  The precleaning unit 100 a and the reversely charged toner cleaning unit 100 b are partitioned by a first insulating seal member 112, and the first insulating seal member 112 is in contact with the precleaning brush roller 101. By partitioning the precleaning unit 100a and the reversely charged toner cleaning unit 100b with the first insulating seal member 112, a discharge occurs between the precleaning brush roller 101 and the reversely charged toner cleaning brush roller 104, or reverse charging. It is possible to prevent the toner removed by the toner cleaning unit 100b from reattaching to the pre-cleaning brush.

  The reversely charged toner cleaning unit 100b and the regular charged toner cleaning unit 100c are partitioned by a second insulating seal member, and the second insulating seal member 113 is in contact with the reversely charged toner cleaning brush roller 104. Yes. By separating the reversely charged toner cleaning unit 100b and the normally charged toner cleaning unit 100c by the second insulating seal member 113, a discharge occurs between the reversely charged toner cleaning brush roller 104 and the normally charged toner cleaning brush roller 107. Or the toner removed by the normally charged toner cleaning unit 100c can be prevented from reattaching to the reversely charged toner cleaning brush roller 104.

  In addition, a third insulating seal member 114 that abuts the regular charged toner cleaning brush roller 107 is provided at the outlet of the cleaning device 100. Thereby, it is possible to suppress the occurrence of discharge between the normally charged toner cleaning brush roller 107 and the tension roller 16.

  Further, the belt cleaning device 100 is provided with an inlet seal 111 and a waste toner case 115. The waste toner case 115 stores the toner removed by the reversely charged toner cleaning unit 100b and the regular charged toner cleaning unit 100c. Further, the waste toner case 115 is detachably attached to the belt cleaning device 100, and the toner collected in the waste toner case 115 is removed by removing the waste toner case 115 from the cleaning device 100 during maintenance or the like. It can be done.

  In the belt cleaning device 100, the toner removed by the reversely charged toner cleaning unit 100b and the regular charged toner cleaning unit 100c is stored in the waste toner case 115, but the configuration is not limited thereto. For example, a reverse charging toner cleaning unit 100b and a regular charging toner cleaning unit 100c may be provided by providing a conveyance member for conveying toner to the conveyance screw 110 at the bottom of the belt cleaning device 100, or by providing an inclined surface toward the conveyance screw 110 at the bottom. The toner removed in step 1 may also be transported to a waste toner tank (not shown) provided in the image forming apparatus main body by the transport screw 110. In addition to the transport screw, a second transport screw that transports the toner removed by the reversely charged toner cleaning unit 100b and the regular charged toner cleaning unit 100c to a waste toner tank (not shown) provided in the image forming apparatus main body. It may be provided.

Each of the cleaning brush rollers 101, 104, and 107 includes a metal rotating shaft member that is rotatably supported, and a brush portion that is formed of a plurality of brush fibers that are erected on the peripheral surface thereof. It is essential that the brush fiber is a conductive brush in which a conductive material is mixed in acrylic, PET, polyester, or the like. The structure of the conductive material at this time may be simply dispersed on the brush surface, or may be a core-sheath structure inserted inside and not exposed to the surface. The brush resistance is preferably 10E4 to 10E9Ω. If the resistance is small, it is easy to inject charges into the toner. If the resistance is large, the electric field strength is small, and an electric field for attracting the toner can be secured unless a high voltage is applied. Disappear. Further, in order to increase the contact probability with the toner, the flocking density is also an important factor and is preferably 70,000 / in ² or more, more preferably 100,000 / in ² or more.

  Further, each cleaning brush roller 101, 104, 107 is driven by a driving means (not shown) so that the brush fiber moves in a direction opposite to the movement direction of the intermediate transfer belt 8 (counter direction) at a contact portion with the intermediate transfer belt. Rotate. By rotating the brush so as to move in the counter direction at the contact portion, the linear velocity difference between the cleaning brush roller and the intermediate transfer belt 8 can be increased. 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. When the linear velocity S1 of the cleaning brush roller and the linear velocity S2 of the intermediate transfer belt are set, a good contact probability can be obtained by setting the linear velocity ratio (S1 / S2) to 0.5 or more.

  Further, the brush fibers of the cleaning brush rollers 101, 104, and 107 may be so-called oblique hairs that are planted in a posture inclined with respect to the normal direction of the rotating shaft member. By making the brush fibers slanted, it is possible to suppress uneven contact between the intermediate transfer belt and the brush compared to the case where the brush fibers are so-called straight hairs extending in the normal direction of the shaft member. In addition, the toner can be removed from the intermediate transfer belt 8.

  In the belt cleaning apparatus 100, SUS rollers are used as the collecting rollers 102, 105, and 108.

  Each of the collection rollers 102, 105, and 108 has a function of adsorbing and collecting toner from the cleaning brush roller to the surface of the collection roller, and a function of carrying the toner adhering to the surface of the collection roller and carrying it to the scraping blade. have. The important factors in collecting toner from the cleaning brush roller to the collecting roller are the electrostatic transfer force of the toner from the cleaning brush roller to the collecting roller and the toner adhering to the collecting roller held on the surface. It is a physical force. The force for electrostatically transferring the toner to the collecting roller is determined by the charge amount of the toner itself and the electric field strength between the brush roller and the collecting roller. The physical force for holding the toner on the surface is a force for holding the toner that has adhered to the collection roller so that it does not move to the brush again until it passes through the contact area between the collection roller and the brush. This force is greatly related to the surface roughness of the collecting roller. When the surface roughness of the collecting roller is good, for example, when it is in a mirror-like state, there is a problem that the holding force is small and it adheres to the brush again by the rubbing force of the brush. On the other hand, if the surface roughness of the collecting roller is poor and the unevenness is large, a cleaning failure due to the scraping blade occurs. The surface roughness Ra of each collecting roller 102, 105, 108 is preferably 0.08 to 1.6 μm. Furthermore, it is essential that no damage is caused against electric discharge and rubbing. Each of the collecting rollers 102, 105, and 108 is made of metal in order to maintain the potential supplied from the core bar for moving from the brush roller to the collecting roller. When the collecting roller is made of metal, the toner easily moves from the brush roller to the surface of the collecting roller and is easily removed by the scraping blade.

  Each scraping blade 103, 106, 109 is a part that plays an important role in removing the toner from the collecting roller and establishing an electrostatic cleaning system. Conventionally, urethane blades have been mainly used as scraping blades. However, the need for a material with a small amount of wear has increased with the demand for a long life of parts. Therefore, stainless steel and phosphor bronze are used as the scraping blade. Furthermore, in order to extend the life, the metal material may be plated with chromium or the like to increase the hardness and reduce the amount of wear.

Next, the cleaning operation of the belt cleaning apparatus 100 will be described.
As shown in FIG. 4, the untransferred toner image and the untransferred toner image that have passed through the secondary transfer portion pass through the contact portion of the entrance seal 111 and are transferred to the position of the pre-cleaning brush roller 101 by the rotation of the intermediate transfer belt 8. The A voltage having a polarity (positive polarity) opposite to the normal charging polarity of the toner is applied to the pre-cleaning brush roller 101, and an electric field formed by a potential difference between the intermediate transfer belt 8 and the surface potential of the pre-cleaning brush roller 101 The negatively charged toner on the intermediate transfer belt 8 is electrostatically attracted and moved to the pre-cleaning brush roller 101. The negative polarity toner that has moved to the pre-cleaning brush roller 101 is transported to a contact position with the pre-collection roller 102 to which a positive voltage having a larger value than that of the pre-cleaning brush roller 101 is applied. Then, the toner that has moved onto the pre-cleaning brush roller 101 is electrostatically adsorbed by the electric field formed by the potential difference between the surface potential of the pre-cleaning brush roller 101 and the surface potential of the pre-collecting roller 102, and the pre-collecting roller 102 The negative toner that has been moved upward and moved to the pre-collection roller 102 is scraped off from the surface of the collection roller by the pre-scraping blade 103. The toner scraped off by the pre-scraping blade 103 is discharged out of the apparatus by the transport screw 110.

  The negative toner, positive toner, and positive transfer residual toner of the untransferred toner image on the intermediate transfer belt 8 that could not be removed by the pre-cleaning brush roller 101 are transferred to the position of the reversely charged toner cleaning brush roller 104. . The reversely charged toner cleaning brush roller 104 is applied with a voltage having the same polarity (negative polarity) as the normal charging polarity of the toner, and is formed by a potential difference between the intermediate transfer belt 8 and the surface potential of the reversely charged toner cleaning brush roller 104. The positively charged toner on the intermediate transfer belt 8 is electrostatically attracted and moved to the reversely charged toner cleaning brush roller 104 by the electric field. The positive polarity toner that has moved to the reversely charged toner cleaning brush roller 104 is transferred to a contact position with the reversely charged toner recovery roller 105 to which a negative polarity voltage larger than that of the reversely charged toner cleaning brush roller 104 is applied. The The toner that has moved onto the reversely charged toner cleaning brush roller 104 is electrostatically adsorbed by an electric field formed by the potential difference between the surface potential of the reversely charged toner cleaning brush roller 104 and the surface potential of the reversely charged toner recovery roller 105. Then, the toner is moved onto the reversely charged toner collecting roller 105. The positive toner moved to the reversely charged toner collecting roller 105 is scraped off from the surface of the collecting roller by the reversely charged toner scraping blade 106.

  Next, the negative polarity toner that could not be removed by the pre-cleaning brush roller 101 is transferred to the regular charged toner cleaning brush roller 107. The toner on the intermediate transfer belt 8 is almost removed by the pre-cleaning brush roller 101 and the reversely charged toner cleaning brush roller 104. Therefore, a very small amount of toner is transferred to the regular charged toner cleaning brush roller 107. A very small amount of toner on the intermediate transfer belt 8 transferred to the normally charged toner cleaning brush roller 107 is applied with a voltage having a polarity (positive polarity) opposite to the normal charging polarity of the toner. The toner is electrostatically attached to 107, collected by the normally charged toner collecting roller 108, and scraped off from the normally charged toner collecting roller 108 by the normally charged toner scraping blade 109.

As described above, according to the belt cleaning apparatus 100, by providing the pre-cleaning brush roller 101, the negative-polarity toner that covers most of the untransferred toner image by the pre-cleaning brush roller 101 is roughly removed. As a result, the amount of toner input to the reversely charged toner cleaning brush roller 104 and the normally charged toner cleaning brush roller 107 can be reduced. As a result, a large amount of toner on the intermediate transfer belt 8 does not hinder the positive toner from adhering to the reversely charged toner cleaning brush roller 104, and the positively charged toner is removed by the reversely charged toner cleaning brush roller 104. It can be satisfactorily removed from the intermediate transfer belt 8. Further, the toner on the intermediate transfer belt transferred to the regular charged toner cleaning brush roller 107 at the most downstream side in the belt moving direction has not been removed by the pre-cleaning brush roller 101 and the reversely charged toner cleaning brush roller 104. The amount is very small. Therefore, the remaining toner can be satisfactorily removed by the normally charged toner cleaning brush roller 107. As a result, even an untransferred toner image in which a large amount of toner is attached to the intermediate transfer belt 8 can be satisfactorily removed from the intermediate transfer belt 8.
Further, the untransferred toner having a smaller amount of toner than the untransferred toner image can be satisfactorily removed by these three cleaning brush rollers 101, 104, and 107.

  In the belt cleaning device 100 described above, the normally charged toner cleaning unit 100c is provided on the most downstream side in the belt moving direction, but the reversely charged toner cleaning unit 100b may be provided on the most downstream side in the belt moving direction. In the belt cleaning apparatus 100, a voltage is applied to each of the collecting rollers 102, 105, and 108 and each of the cleaning brush rollers 101, 104, and 107, but a voltage is applied only to each of the collecting rollers 102, 105, and 108. It may be configured. In this case, a bias voltage somewhat lower than the bias voltage applied to the recovery roller is applied to the cleaning brush roller in a form through the contact portion with the recovery roller due to a potential drop due to the fiber resistance of the cleaning brush roller. It becomes a state. Thereby, a potential difference is formed between the collection roller and the cleaning brush roller, and the toner can be electrostatically moved from the cleaning brush roller to the collection roller by a potential gradient in the direction of the collection roller.

  Further, as described above, in the belt cleaning device 100 of the present embodiment, the scraping blades 103, 106, and 109 are metal blades, and the collecting rollers 102, 105, and 108 are metal rollers. Since metal has a strong and hard metal structure and a weak and soft metal structure, the hardness of the metal blade differs in the axial direction. Further, the average hardness in the circumferential direction also differs in the axial direction on the surface of the metal roller. As a result, if the hard part of the metal blade always rubs against the part where the average hardness in the circumferential direction of the metal roller surface is soft, that part of the metal roller surface wears faster than the other parts, resulting in uneven wear. End up. Similarly, when the soft part of the metal blade always rubs against the part whose average hardness in the circumferential direction of the metal roller surface is hard, the part wears faster than the other parts, resulting in uneven wear. . Thus, when a metal blade is used as the scraping blade and a metal roller is used as the collection roller, uneven wear occurs on the surface of the scraping blade or the collection roller.

  Therefore, the belt cleaning apparatus 100 according to the present embodiment moves the scraping blades 103, 106, and 109 back and forth in the axial direction so that the collecting rollers 102, 105, and 108 are axially moved with respect to the scraping blades. It is provided with a moving mechanism that is a moving means for reciprocating.

FIG. 5 is a schematic configuration diagram showing the belt cleaning device 100 and the moving mechanism, and FIG. 6 is a cross-sectional view taken along the line AA of FIG.
As shown in FIG. 6, the moving mechanism includes a cam plate 116, and the cam plate 116 is fixed to the right end portion in the drawing of the shaft of the reversely charged toner collecting roller 105. Supporters 103b, 106b, and 109b are provided at both ends of the holders 103a, 106a, and 109a that hold the scraping blades 103, 106, and 109. These support parts 103b, 106b, and 109b are provided on both sides of the cleaning device. It is supported by the plates 117a and 117b. Springs 103c, 106c, and 109c are inserted into the left support portion in the drawing, and one end of the spring is in contact with the left plate 117a in the drawing, and the other end is in contact with the holder, and the scraping blade is illustrated. It is energizing to the middle right. The right support portion of each scraping blade in the drawing passes through the right side plate 117b, and has cam contact portions 103d, 106d, and 109d at end portions. On the opposite surface of the right side plate 117b of the cam plate 116, there are three circular cam portions 116a, 116b, 116c centered on the rotation center of the cam plate 116. Each cam portion 116a, 116b, 116c has a top portion and a bottom portion, and the height from the surface of the cam plate gradually increases from the bottom portion toward the top portion. The cam contact portion 103d of the pre-scraping blade contacts the pre-cam portion 116a provided at the end of the cam plate 116, and the cam contact portion 106d of the reversely charged toner scraping blade is the reversely charged toner cam of the cam plate 116. It is in contact with the portion 116b. Further, the cam contact portion 109 d of the normally charged toner scraping blade is in contact with the normally charged toner cam portion 116 c of the cam plate 116.

  When the reversely charged toner collection roller 105 rotates, the cam plate 116 rotates. When the cam plate 116 rotates, the cam contact portions 103d, 106d, and 109d slide on the cam portions 116a, 116b, and 116c of the cam plate 116, respectively. When the cam contact portion slides between the bottom portion and the top portion of the cam portion, the scraping blade moves to the left side in the drawing. When the cam contact portion slides between the top portion and the bottom portion of the cam portion, the scraping blade moves to the right side in the drawing. Thereby, each scraping blade 103, 106, 109 reciprocates in the axial direction of the collection roller. A suitable stroke is about 0.3 to 0.6 mm. As described above, the scraping blade reciprocates in the axial direction of the collecting roller, so that the portion of the scraping blade that slides on the surface of the collecting roller changes in the axial direction. Thus, the scraping blade does not always rub against the same position in the axial direction of the collection roller. As a result, the portion having the average hardness in the circumferential direction of the collecting roller does not always rub against the soft portion of the scraping blade, and uneven wear of the scraping blade can be suppressed. In addition, the portion where the average hardness in the circumferential direction of the collecting roller is not always rubbed against the hard portion of the scraping portion, and uneven wear on the surface of the collecting roller can be suppressed.

  When the reciprocating motions of the plurality of scraping blades are synchronized, an axial load is applied to the belt cleaning device 100, and the components of the belt cleaning device including the side plates vibrate. If the frequency generated at this time is the same as the natural frequency of any of the components of the belt cleaning device, the component will resonate. When resonant vibration occurs, the side plates 117a and 117b that support the component parts are distorted, and the scraping blades are twisted. As a result, the biting amount of the scraping blade with respect to the collecting roller varies in the axial direction, and when the biting amount increases, the contact pressure on the collecting roller increases and the wear amount increases. On the other hand, when the amount of biting is reduced, the contact pressure is reduced and the wear amount is reduced. As a result, the abrasion of the scraping blade varies in the axial direction. Therefore, it is preferable to give a phase difference to the reciprocating motion of each scraping blade 103, 106, 109. As a result, the scraping blade moves sequentially to the left and right ends, and compared with the case where the reciprocating motions of the plurality of scraping blades are synchronized, the generation of resonance vibration can be suppressed. Abrasion variation in the axial direction of the blade can be reduced. An example of the reciprocating movement of each scraping blade 103, 106, 109 when a phase difference is given is shown in FIG. It is desirable that the phase difference between the pre-scraping blade 103 and the reversely charged toner scraping blade 106 be the same as the phase difference between the reversely charged toner scraping blade 106 and the regular charged toner scraping blade 109.

Next, the verification experiment will be described.
Each scraping blade was reciprocated at a stroke of 0.5 mm, and the amount of wear on each scraping blade and each collecting roller surface when an A4 size 800K paper feeding experiment was conducted, without reciprocating each scraping blade. The amount of wear on each scraping blade and the surface of each collecting roller when an A4 size 800K paper feeding experiment was conducted was examined. Specific experimental conditions are shown below.
-Conditions for each cleaning brush roller 101, 104, 107 Material: Conductive PET fiber Outer diameter: φ15mm
Core diameter: φ6mm
Resistance: 10 7 Ωcm
Flocking density: 100,000 pieces / inch square Rotational speed: 250 mm / s
Rotation direction: Counter direction with respect to the intermediate transfer belt Biting amount: 1 mm
Applied voltage: 1.6KV
-Conditions for each collection roller 102, 105, 108 Material: SUS
Outer diameter: φ14mm
Surface roughness: Ra0.5
Rotation speed: 250mm / S
Rotation direction: Counter against brush roller Biting amount: 1.5mm
Applied voltage: 2.0KV
-Conditions for each scraping blade 103, 106, 109 Material: SUS
Thickness: 0.1mm
Free length: 8mm
Surface roughness: Ra0.55
Pressing amount to collection roller: 1mm
・ Other conditions Cam plate 116
Material: POM
Cam deviation: 0.5mm

FIG. 8 shows the pre-scraping blade 103 after the verification experiment in the direction of the VK8000 (key ence) from the front end surface (surface having a front end ridge line portion in contact with the pre-collecting roller 102 on one side and parallel to the thickness direction of the pre-scraping blade 103). It is a conceptual diagram when it observes by manufacture. (A) is a conceptual diagram when the pre-scraping blade 103 is not reciprocated, and (b) is a conceptual diagram when the pre-scraping blade 103 is reciprocated.
As shown in FIG. 8A, it can be seen that the wear width of the person who did not perform the reciprocating motion of the pre-scraping blade 103 is 40 μm at the minimum and 80 μm at the maximum, and the variation in the wear in the axial direction is large. This is presumably because the soft portion of the pre-scraping blade 103 always rubbed with a portion of the surface of the pre-collection roller 102 having a high average hardness in the circumferential direction, so that the portion was worn early and was unevenly worn. Then, toner or brush powder enters the part of the pre-scraping blade 103 that has been worn away, and these powders become a grindstone material, further accelerating the wear of the part, and the part with a maximum wear width of 80 μm It is thought that it occurred. Although the reversely charged toner scraping blade 106 and the regular charged toner scraping blade 109 are not shown, the same results as those of the pre-scraping blade 103 were obtained.

  On the other hand, as shown in FIG. 8B, when the pre-scraping blade 103 is reciprocated, the wear width is 40 μm at the minimum and 45 μm at the maximum, and both the maximum wear amount and the wear variation are reduced. ing. This is because the pre-scraping blade 103 was reciprocated, and the average surface hardness of the pre-collection roller 102 and the soft part were rubbed with the pre-scraping blade 103 on average. It is considered that the part with the scraping blade was worn on average without causing uneven wear. Although the reversely charged toner scraping blade 106 and the regular charged toner scraping blade 109 are not shown in the figure, a reciprocating motion similarly results in a reduction in both the maximum wear amount and wear variation. It was.

FIG. 9 is a diagram illustrating a measurement result of the roughness of the pre-collection roller 102 surface. The surface roughness of the pre-collection roller was measured with Surfcom 1500DX (manufactured by Tokyo Seimitsu). FIG. 9A is a measurement result of the surface roughness of the pre-collecting roller when the pre-scraping blade 103 is not reciprocated, and FIG. 9B is a diagram illustrating the re-sliding motion of the pre-scraping blade 103. It is a measurement result of the pre-recovery roller surface roughness when there is not.
As shown in FIG. 9A, the person who did not perform the reciprocating motion of the pre-scraping blade had a maximum height Rmax = 1.0 μm on the surface of the pre-collecting roller, but as shown in FIG. 9B. In addition, when the pre-scraping blade 103 is reciprocated, the maximum height Rmax of the pre-collection roller surface is 0.2 μm, which is very small. This is because the hard part of the pre-scraping blade 103 always rubs against the part whose average circumferential hardness on the surface of the pre-scraping roller is always soft. It is considered that the maximum height is significantly increased as a result of uneven wear occurring in a portion of the axial direction 102. On the other hand, when the pre-scraping blade 103 is reciprocated, the hard part and the soft part of the pre-scraping blade 103 rub against the surface of the pre-collecting roller on average. It is considered that the wear occurred on average without causing uneven wear. Similarly, the reversely charged toner collecting roller 105 and the regular charged toner collecting roller 108 can suppress uneven wear by reciprocating the scraping blade.

  In addition, when the scraping blades 103, 106, 109 did not reciprocate, a cleaning failure occurred on the surface of the printing recording paper from about 400k. As shown in FIGS. 8 (a) and 9 (a), the part with the scraping blade and the part in the axial direction on the surface of the collecting roller are unevenly worn, so the toner slips from the part. This is presumably because the toner could not be scraped off favorably from the collecting roller. That is, as a result of the toner being unable to be scraped off favorably from the collecting roller, the collecting ability of each collecting roller 102, 105, 108 is reduced, and new toner adhering to each collecting roller 102, 105, 108 is reduced. . When the collecting ability of each of the collecting rollers 102, 105, and 108 is reduced, the toner remaining on the cleaning brush rollers 101, 104, and 107 is increased without being collected by the collecting roller. When the toner remaining on the cleaning brush rollers 101, 104, and 107 increases, the toner that newly adheres to the cleaning brush rollers 101, 104, and 107 from the intermediate transfer belt 8 decreases. As a result, the cleaning performance of each of the cleanings 100a, 100b, and 100c is lowered, and it is considered that a cleaning failure finally occurred.

  On the other hand, those who reciprocated each of the scraping blades 101, 104, and 107 did not cause cleaning failure up to 800k. This could suppress uneven wear on the surface of each collecting roller and uneven wear on each scraping blade, so that the toner adhering to each collecting roller surface over time can be removed by each scraping blade 103, 106, 109. It is thought that it was able to be scraped off. Thereby, it is considered that the recovery capability of each of the recovery rollers 102, 105, 108 was maintained over time, and the cleaning performance of each of the cleaning brushes 101, 104, 107 could be maintained over a long period of time. As a result, it is considered that good cleaning properties could be maintained over time.

  Next, a modified example of the belt cleaning device will be described.

[Modification 1]
FIG. 10 is a schematic configuration diagram of a main part of the belt cleaning device 100-1 of the first modification.
As shown in FIG. 10, the belt cleaning device 100-1 according to the first modification is provided with cam plates 121, 122, 123 on the collection rollers 102, 105, 108. As shown in the figure, the cam portion of each cam plate is in contact with the end of the holder of the corresponding scraping blade.

  When each collection roller is rotated, each cam plate rotates, and as a result, each scraping blade reciprocates in the axial direction of the collection roller. Even in such a configuration, the collection roller can reciprocate relative to the scraping blade, and the rubbing portion of the scraping blade with the surface of the collection roller can be changed in the axial direction. Therefore, uneven wear of the scraping blade or the collection roller surface can be suppressed.

[Modification 2]
FIG. 11 is a schematic configuration diagram of a main part of a belt cleaning device 100-2 according to the second modification.
The belt cleaning device 100-2 according to the second modification is configured to reciprocate the collecting rollers 102, 105, and 108 in the axial direction.
As shown in FIG. 11, springs 102b, 105b, and 108b are inserted into the left shafts of the collection rollers 102, 105, and 108 in the drawing. One end of each spring 102b, 105b, 108b is in contact with the left plate 117a, and the other end is in contact with the left flange in the drawing of the corresponding collection roller, and urges each collection roller to the right in the drawing. .
Cam portions 102a, 105a, 108a are formed on the right flanges of the collecting rollers 102, 105, 108 in the drawing, and the cam portions 102a, 105a, 108a correspond to the corresponding provided on the right plate 117b in the drawing. The cam contacts 131, 132, 133 are in contact.

  When each collection roller 102, 105, 108 rotates, cam portions 102a, 105a, 108a provided on the right flange in the drawing of each collection roller 102, 105, 108 slide with the corresponding cam contact portion. Thereby, each collection | recovery roller reciprocates to the left and right (collection roller axial direction) in the figure. Also in the cleaning device 100b of the second modified example, when the collection rollers 102, 105, and 108 are reciprocated, the collection roller is reciprocated relative to the scraping blade, and the recovery roller of the scraping blade is The rubbing location with the surface can be changed in the axial direction. Therefore, uneven wear of the scraping blade or the collection roller surface can be suppressed.

Next, toner that is preferably used in the printer will be described.
The toner preferably used in this printer preferably has a volume average particle diameter of 3 to 6 [μm] in order to reproduce minute dots of 600 dpi or more. A toner having a ratio (Dv / Dn) of volume average particle diameter (Dv) to number average particle diameter (Dn) in the range of 1.00 to 1.40 is preferable. The closer (Dv / Dn) is to 1.00, the sharper the particle size distribution. With such a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution is uniform, a high-quality image with little background fogging can be obtained, and the electrostatic transfer method has a high transfer rate. can do.

The shape factor SF-1 of the toner is preferably in the range of 100 to 150, and the shape factor SF-2 is preferably in the range of 100 to 180. FIG. 12 is a diagram schematically showing the shape of the toner in order to explain the shape factor SF-1. The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) ² / AREA} × (100π) / 4 Formula (1)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases.

FIG. 13 is a diagram schematically showing the shape of the toner in order to explain the shape factor SF-2. The shape factor SF-2 indicates the ratio of unevenness in the shape of the toner, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner on the two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-2 = {(PERI) ² / AREA} × 100 / (4π) (2)
When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent.

  Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) and analyzing it. Calculated. When the toner shape is close to a sphere, the transfer rate increases. More specifically, when the toner adheres to the photoconductor, the main forces that act on the surface of the photoconductor include a mirror power and a van der Waals force. The mirror power greatly depends on the charge amount and its distance. In the case of a toner having a concavo-convex surface such as a pulverized toner produced by conventional pulverization, the convex portion is intensively charged by frictional charging. Since the electric charges are concentrated on the portion, the mirror force increases when the convex portion is in contact with or very close to the surface of the photosensitive member. On the other hand, a toner having a spherical surface or a shape close to a spherical surface is uniformly charged on the surface. Further, the contact state with the image carrier is almost point-like, and the amount of charge at the portion in contact with or very close to the surface of the photoreceptor is small, and the mirror power is small. Further, since the surface shape is spherical, the toner contacts almost at a point, so the van der Waals force is also reduced. As described above, from the viewpoint of contact force, in the case of toner having a nearly spherical shape, the reflection force, van der Waals force, that is, the adhesion force to the photosensitive member is reduced, and the transfer rate is increased. By increasing the transfer rate, the amount of toner remaining after transfer is small and the amount of toner consumption is reduced, thereby improving the economy. If the shape factor SF-1 exceeds 150 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.

  In addition, a toner suitably used for a color printer is a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent are dispersed in an organic solvent. Is a toner obtained by crosslinking and / or elongation reaction in an aqueous solvent. Hereinafter, the constituent material and the manufacturing method of the toner will be described.

(polyester)
The polyester is obtained by a polycondensation reaction between a polyhydric alcohol compound and a polycarboxylic acid compound.
Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

  Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1. The polycondensation reaction of polyhydric alcohol (PO) and polycarboxylic acid (PC) is performed at 150 to 280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, while reducing the pressure as necessary. The produced water is distilled off to obtain a polyester having a hydroxyl group. The hydroxyl value of the polyester is preferably 5 or more, and the acid value of the polyester is usually 1 to 30, preferably 5 to 20. By giving an acid value, it tends to be negatively charged, and furthermore, when fixing to a recording paper, the affinity between the recording paper and the toner is good and the low-temperature fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation. The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. A weight average molecular weight of less than 10,000 is not preferable because offset resistance deteriorates. On the other hand, if it exceeds 400,000, the low-temperature fixability is deteriorated.

  In addition to the unmodified polyester obtained by the above polycondensation reaction, the polyester preferably contains a urea-modified polyester. The urea-modified polyester is obtained by reacting a terminal carboxyl group or hydroxyl group of the polyester obtained by the above polycondensation reaction with a polyvalent isocyanate compound (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. It is obtained by cross-linking and / or extending the molecular chain by the reaction of the amine with amines. Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-isocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; phenol derivatives, oximes, caprolactam And a combination of two or more of these. The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5/1, the low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1/1, when a urea-modified polyester is used, the urea content in the ester becomes low and hot offset resistance deteriorates. The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt%. . If it is less than 0.5 wt%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 wt%, the low-temperature fixability deteriorates. The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  Next, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acid (B5), and amino acid block of B1 to B5 (B6).

  Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of B1 to B5 blocked amino groups (B6) include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is more than 2/1 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated.

  The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

  The urea-modified polyester is produced by a one-shot method or the like. Polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and water produced while reducing the pressure as necessary. Distill off to obtain a polyester having a hydroxyl group. Subsequently, at 40-140 degreeC, this is made to react with polyvalent isocyanate (PIC), and the polyester prepolymer (A) which has an isocyanate group is obtained. Further, this (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a urea-modified polyester.

  When reacting (PIC) and when reacting (A) and (B), a solvent may be used if necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to isocyanates (PIC), such as tetrahydrofuran (such as tetrahydrofuran).

  In addition, in the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator can be used as necessary to adjust the molecular weight of the resulting urea-modified polyester. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

  The weight average molecular weight of the urea-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester or the like is not particularly limited when the above-mentioned unmodified polyester is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. When the urea-modified polyester is used alone, its number average molecular weight is usually 2000-15000, preferably 2000-10000, more preferably 2000-8000. If it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color image forming apparatus deteriorate.

  By using the unmodified polyester and the urea-modified polyester in combination, the low-temperature fixability and the glossiness when used in a full-color image forming apparatus are improved. Therefore, it is preferable to use the urea-modified polyester alone. The unmodified polyester may include a polyester modified with a chemical bond other than a urea bond.

  The unmodified polyester and the urea-modified polyester are preferably at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, it is preferable that the unmodified polyester and the urea-modified polyester have a similar composition.

  The weight ratio of unmodified polyester to urea-modified polyester is usually 20/80 to 95/5, preferably 70/30 to 95/5, more preferably 75/25 to 95/5, and particularly preferably 80 /. 20-93 / 7. When the weight ratio of the urea-modified polyester is less than 5%, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The glass transition point (Tg) of the binder resin containing unmodified polyester and urea-modified polyester is usually 45 to 65 ° C, preferably 45 to 60 ° C. If it is less than 45 ° C., the heat resistance of the toner deteriorates, and if it exceeds 65 ° C., the low-temperature fixability becomes insufficient.

  In addition, since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners.

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Lead yellow, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR1, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R) , Tartrazine rake, quinoline yellow rake, anthrazan yellow BGL, isoindolinone yellow, bengara, red lead, lead vermilion, cadmium red, cadmium mercurial red, antimon vermilion, permanent red 4R, para red, phissa red Parachlor ortho nitro Nirin Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, thioindigo maroon, oil red, quinacridone red, pyrazolone red, Riazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalo Cyanine green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded together with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

(Charge control agent)
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSYVP 2038, copy blue PR of triphenylmethane derivative, copy charge NEG VP2036 of quaternary ammonium salt, copy charge NX VP434 (manufactured by Hoechst), LR1-901, LR-147 which is a boron complex (manufactured by Nippon Carlit) ), Copper phthalocyanine, perylene, quinacridone, azo face , Sulfonate group, carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. The effect on high temperature offset is exhibited without applying a release agent such as oil. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .

  The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably ⁵ × ¹⁰ -3~2 [μm], it is particularly preferably ⁵ × ¹⁰ -3~0.5 [μm]. Moreover, it is preferable that the specific surface area by BET method is 20-500 [m < ² > / g]. The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%. Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing are performed using particles having an average particle size of 5 × 10 −4 μm or less, the electrostatic force and van der Waals force with the toner are markedly improved. Even when stirring and mixing inside the developing device is performed, a fluidity-imparting agent is not detached from the toner, a good image quality that does not cause fireflies and the like is obtained, and a reduction in residual toner is further achieved. . Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large. However, when the added amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained, that is, repeated copying. Stable image quality can be obtained even if

  Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.

(Toner production method)
(1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.
The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

(2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.

  The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical.

Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.
As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

  In addition, examples of the cationic surfactant include aliphatic quaternary ammonium salts such as aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, and perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts. , Benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 (Daikin Industries) Manufactured), MegaFuck F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footgent F-300 (Neos), and the like.

  The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 90%. For example, polymethyl methacrylate fine particles 1 [μm] and 3 [μm], polystyrene fine particles 0.5 [μm] and 2 [μm], poly (styrene-acrylonitrile) fine particles 1 [μm], trade name is PB- 200H (manufactured by Kao Corporation), SGP (manufactured by Sokensha), technopolymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.) and the like. In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, in order to make the particle size of the dispersion 2 to 20 [μm], a high-speed shearing method is preferable. When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is usually 1000 to 30000 [rpm], preferably 5000 to 20000 [rpm]. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

(3) At the same time as the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group.
This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

(4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.
In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

(5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner. The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like.

  Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

  The toner has a substantially spherical shape and can be represented by the following shape rule. 14A, 14B, and 14C are diagrams schematically illustrating the shape of the toner. 14A, 14B, and 14C, when a substantially spherical toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), the toner is defined. The ratio of the major axis to the minor axis (r2 / r1) (see FIG. 14B) is 0.5 to 1.0, and the ratio of the thickness to the minor axis (r3 / r2) (FIG. 14C )) Is preferably in the range of 0.7 to 1.0. When the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the dot reproducibility and transfer efficiency are inferior because of being away from the true spherical shape, and high-quality image quality cannot be obtained. On the other hand, if the ratio of thickness to minor axis (r3 / r2) is less than 0.7, the shape is close to a flat shape, and a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the minor axis (r3 / r2) is 1.0, the rotating body has a major axis as a rotation axis, and the fluidity of the toner can be improved.

  Note that r1, r2, and r3 were measured with a scanning electron microscope (SEM) while changing the angle of field of view and taking pictures.

  The cleaning device of the present invention can also be applied to a cleaning device including a reversely charged toner cleaning unit 100b and a regular charged toner cleaning unit 100c. In addition, the configuration includes a polarity control unit that aligns the polarity of the toner on the intermediate transfer belt, and a cleaning unit that removes the toner of the polarity aligned by the polarity control unit downstream of the polarity control unit in the moving direction of the intermediate transfer belt. It can also be applied to other cleaning devices. In this case, the cleaning unit applies a voltage having a polarity opposite to the polarity aligned by the polarity control unit to the cleaning brush roller, and applies a voltage having the same polarity as the voltage applied to the cleaning brush to the recovery roller made of a metal roller. Apply a large voltage. Then, electrostatic cleaning is established by scraping off toner adhering to the surface of the collecting roller with a scraping blade made of a metal blade. As a polarity control means, a conductive member such as a conductive brush or conductive blade is brought into contact with the intermediate transfer belt, and a voltage is applied to the conductive member, so that the toner polarity on the intermediate transfer belt is aligned. Alternatively, the polarity of the toner on the intermediate transfer belt may be made uniform using a corona charger or the like. Further, the pre-cleaning unit described above may be provided upstream of the polarity control unit in the intermediate transfer belt moving direction.

  In the belt cleaning device 100, the positively charged toner on the intermediate transfer belt 8 is removed by the reversely charged toner cleaning brush roller 104. However, the reversely charged toner cleaning unit 100b is changed to a polarity control unit so that the intermediate toner is removed. A configuration in which the positive toner on the transfer belt 8 is not removed may be employed. In this case, the toner on the intermediate transfer belt 8 that has passed through the pre-cleaning brush roller 101 is made to have a negative polarity by the polarity control unit and is sent to the normally charged toner cleaning brush roller 107 downstream in the belt moving direction from the polarity control unit. Be transported. Then, the negatively charged toner is removed by the normally charged toner cleaning brush roller 107. As a means for injecting negative charge into the toner on the intermediate transfer belt 8 by the polarity control unit, a conductive brush, a conductive blade, a corona charger, or the like may be used. Also, instead of aligning the charging polarity of the toner to negative polarity, arrange a cleaning brush roller to which a negative voltage is applied downstream of the polarity control unit in the belt moving direction so that it is aligned to positive polarity. A configuration in which toner having a positive polarity on the intermediate transfer belt is removed may be employed. Even in such a configuration, since the toner of the untransferred toner image is roughly removed from the intermediate transfer belt 8 by the pre-cleaning brush roller 101, the amount of toner transferred to the polarity control unit is reduced. Therefore, the polarity control unit can satisfactorily align the toner on the intermediate transfer belt 8 with one polarity. As a result, the toner on the intermediate transfer belt 8 can be satisfactorily electrostatically removed by the cleaning brush roller disposed downstream of the polarity control unit. Therefore, even if an untransferred toner image to which a large amount of toner is attached is input to the belt cleaning device 100, it can be satisfactorily cleaned.

  Further, the cleaning device of the present invention can be applied not only to the belt cleaning device 100 for cleaning the front surface of the intermediate transfer belt but also to the cleaning device 500 for the paper conveying belt 51 as shown in FIG. . As shown in FIG. 15, a paper transport belt 51 as a member to be cleaned used in an image forming apparatus of a tandem type direct transfer system comes into contact with the photoreceptors 1Y, 1M, 1C, 1K, and Y, M, C, A primary transfer nip for K is formed. Then, in the process of conveying the recording paper P from the left side to the right side in the figure along with its endless movement while holding the recording paper P on its surface, the primary transfer nip for Y, M, C, K is used. In order. As a result, the Y, M, C, and K toner images are superimposed and primarily transferred onto the recording paper P. Contamination such as toner adhering to the paper transport belt 51 after passing through the primary transfer nip for K is removed by the transport belt cleaning device 500. The optical sensor unit 150 is disposed so as to face the front surface of the paper transport belt 51 with a predetermined gap. Also in the printer shown in FIG. 15, image density control and positional deviation amount correction control are performed at a predetermined timing, a predetermined toner pattern (gradation pattern, chevron patch) is formed on the paper transport belt 51, and the optical sensor unit 150. Then, the toner pattern is detected, and a predetermined correction process is executed based on the detection result. A toner pattern which is an untransferred toner image detected by the optical sensor unit 150 is removed by the conveyor belt cleaning device 500. Thus, the paper transport belt 51 has a function as an image carrier that carries a toner image.

  By applying the cleaning device of the present invention to the transport belt cleaning device 500, uneven wear of the collection roller and scraping blade can be suppressed, and the transport belt surface can be satisfactorily cleaned over a long period of time.

  The cleaning device of the present invention can also be applied to the drum cleaning device 4 as shown in FIG. An untransferred toner image such as a toner consumption pattern when a refresh mode for refreshing the inside of the developing device is executed and a toner image on the photosensitive member when a paper jam occurs is input to the drum cleaning device 4. By applying the cleaning device of the present invention to the drum cleaning device 4, uneven wear of the recovery roller and scraping blade can be suppressed, and the surface of the photoreceptor can be cleaned well over a long period of time.

  As described above, according to the cleaning device of the present embodiment, the cleaning brush roller as a surface-movable cleaning member that electrostatically moves the toner on the intermediate transfer belt 8 that is a surface-moving object to be cleaned to its own surface and removes it. The toner on the cleaning brush roller is electrostatically moved to its surface and recovered, and the recovery roller is a surface-movable recovery member, and the toner on the recovery roller is scraped off by rubbing against the surface of the recovery roller. And a scraping blade as a scraping member to be removed. Then, a moving mechanism is provided as a moving means for reciprocating the collecting roller relative to the scraping blade in the collecting roller axial direction. Thus, the scraping blade does not always rub against the same position in the axial direction of the collection roller. As a result, the portion having the average hardness in the circumferential direction of the collecting roller does not always rub against the soft portion of the scraping blade, and uneven wear of the scraping blade can be suppressed. In addition, the portion where the average hardness in the circumferential direction of the collecting roller is not always rubbed against the hard portion of the scraping portion, and uneven wear on the surface of the collecting roller can be suppressed.

Further, the collection roller and the scraping blade are formed of a metal material. By configuring the collecting roller with a metal material, a potential difference between the surface of the collecting roller and the brush can be favorably taken, and the toner can be easily moved from the brush roller to the surface of the collecting roller. Further, the toner on the surface of the collection roller is more easily removed by the scraping blade than when the collection roller is made of an elastic body such as a rubber material. Further, by configuring the scraping blade with a metal material, it is possible to suppress wear compared to the urethane blade, and to extend the life of the scraping blade.
In addition, it tends to occur when the recovery roller and scraping blade are made of metal, but as described above, the recovery roller can be effectively moved by reciprocating in the recovery roller axial direction relative to the scraping blade. Uneven wear can be suppressed.

  In addition, a normally charged toner cleaning brush roller 107 as a normally charged toner cleaning member for removing the normally charged toner charged to the normally charged polarity of the toner on the intermediate transfer belt, and a normally charged toner attached to the normally charged toner cleaning brush roller 107 are used. A regular charged toner cleaning unit 100c including a regular charged toner collecting roller 108 as a regular charged toner collecting member to be collected and a regular charged toner scraping member for scraping the regular charged toner of the regular charged toner collecting roller 108 is provided. Further, a reversely charged toner cleaning brush roller 104 as a reversely charged toner cleaning member for removing reversely charged toner charged to a polarity opposite to the normal charged polarity of the toner on the intermediate transfer belt, and a reversely charged toner attached to the reversely charged toner cleaning brush roller A reversely charged toner comprising a reversely charged toner collecting roller 105 as a reversely charged toner collecting member for collecting toner and a reversely charged toner scraping blade as a reversely charged toner scraping member for scraping the reversely charged toner of the reversely charged toner collecting roller A cleaning unit is included. Thereby, the normally charged toner and the reversely charged toner on the intermediate transfer belt can be removed, and the toner on the intermediate transfer belt can be favorably removed. Then, the regular charged toner collecting roller is reciprocated in the axial direction of the regular charged toner collecting roller relative to the regular charged toner scraping blade. Thereby, uneven wear of the normally charged toner collecting roller and the normally charged toner scraping blade can be suppressed. The reversely charged toner collecting roller is reciprocally moved in the axial direction of the reversely charged toner collecting roller relative to the reversely charged toner scraping blade. Thereby, uneven wear of the reversely charged toner collecting roller and the reversely charged toner scraping blade can be suppressed.

  In addition, the reciprocating movement of the normally charged toner collecting roller relative to the normally charged toner scraping blade relative to the normally charged toner scraping blade and the reverse charging toner collecting relative to the reversely charged toner scraping blade of the reversely charged toner collecting roller. The phase with the reciprocating movement in the roller axis direction was made different. Thereby, resonance vibration can be suppressed and variation in wear can be suppressed.

  Further, the cleaning device of this embodiment uses the cam mechanism to reciprocate the collection roller in the collection roller axial direction relative to the regular charged toner scraping blade. By using the cam mechanism, the rotational motion can be converted into a reciprocating motion, and the recovery roller is driven relative to the regular charged toner scraping blade by using the rotational drive of the recovery roller or the rotational drive of the cleaning brush roller. In particular, it can be reciprocated in the collecting roller axial direction. Thereby, it is not necessary to newly provide another driving means for reciprocating movement, the number of parts can be reduced, and the cost can be reduced.

  Further, by using the above-described cleaning device as a cleaning device for cleaning the surface of the image carrier of the image forming apparatus, good cleaning properties can be maintained over time, and good images can be obtained over time.

  Further, by using a toner having a shape factor SF1 of 100 or more and 150 or less and an average particle diameter of 6 μm or less as the toner, the toner charge amount distribution becomes uniform, and a high-quality image with little background fogging can be obtained. Also, the electrostatic transfer method can increase the transfer rate.

4: Drum cleaning device 8: Intermediate transfer belt 51: Paper transport belt 100: Belt cleaning device 100a: Pre-cleaning unit 100b: Reversely charged toner cleaning unit 100c: Regularly charged toner cleaning unit 101: Pre-cleaning brush roller 102: Pre-collecting roller 103: Pre-scraping blade 104: Reversely charged toner cleaning brush roller 105: Reversely charged toner collecting roller 106: Reversely charged toner scraping blade 107: Regularly charged toner cleaning brush roller 108: Regularly charged toner collecting roller 109: Regularly charged toner scraping Take blades 116, 121, 122, 123: cam plate 500, conveyor belt cleaning device

JP 2006-58422 A

Claims (7)

A surface-movable cleaning member that electrostatically moves toner on the surface to be cleaned and moves it to its own surface;
A surface-movable recovery member that electrostatically moves and recovers the toner on the cleaning member to its own surface;
In a cleaning device including a scraping member that scrapes off the toner on the recovery member by rubbing against the surface of the recovery member,
A cleaning apparatus comprising a moving means for reciprocating the recovery member relative to the scraping member in the recovery member axial direction. The cleaning device according to claim 1.
A cleaning device, wherein the recovery member and the scraping member are made of a metal material. The cleaning device according to claim 1 or 2,
A normally charged toner cleaning member that removes the normally charged toner charged to the normally charged polarity of the toner on the object to be cleaned; a normally charged toner collecting member that collects the normally charged toner attached to the normally charged toner cleaning member; and A regular charged toner cleaning unit comprising a regular charged toner scraping member that scrapes the regular charged toner of the regular charged toner collecting member;
A reversely charged toner cleaning member for removing reversely charged toner charged to a polarity opposite to the normal charge polarity of the toner on the object to be cleaned, and a reversely charged toner recovery member for recovering the reversely charged toner attached to the reversely charged toner cleaning member And a reversely charged toner cleaning unit comprising a reversely charged toner scraping member that scrapes off the reversely charged toner of the reversely charged toner collecting member,
The moving means reciprocates the regular charged toner collecting member in the axial direction of the regular charged toner collecting member relative to the regular charged toner scraping member, and the reverse charged toner collecting member A cleaning device that reciprocates in the axial direction of the reversely charged toner collecting member relative to the reversely charged toner scraping member. The cleaning device according to claim 3.
The moving means includes a reciprocating movement of the regular charged toner collecting member in the axial direction relative to the regular charged toner scraping member relative to the regular charged toner collecting member, and the reverse charged toner scraping member of the reverse charged toner collecting member. A cleaning device configured to be different in phase from the reciprocating movement in the axial direction of the reversely charged toner collecting member relative to the above. The cleaning device according to any one of claims 1 to 4,
The above-mentioned moving means is reciprocatingly moved using a cam mechanism. In an image forming apparatus for forming an image on a recording material by finally transferring the toner image formed on the image bearing member onto the recording material from the image bearing member,
6. An image forming apparatus using the cleaning device according to claim 1 as a cleaning device for cleaning residual toner remaining on the image carrier after transfer. The image forming apparatus according to claim 6.
An image forming apparatus using a toner having a shape factor SF1 of 100 to 150 and an average particle diameter of 6 μm or less as the toner.

Images