JP5532410B2 - Cleaning device and image forming apparatus - Google Patents

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, facsimiles, 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 the toner will roll. 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. Further, 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 collecting roller and a metal blade is used as the scraping blade, there is a problem that in the initial stage of use, the toner slips through the contact portion between the scraping blade and the collecting roller, resulting in an initial scraping failure. there were. As a result of intensive studies by the present inventors on the above problems, the following has been found. That is, since the scraping blade and the collection roller are made of a metal material, unlike the elastic member such as a rubber material, the scraping blade and the collection roller are not elastically deformed when the scraping blade is brought into contact with the collection roller. For this reason, in the initial stage of use, the tip ridge line portion of the scraping blade is in contact with the collecting roller, and the scraping blade is in line contact with the collecting roller. When the scraping blade is in line contact with the collecting roller, if there is a slight undulation at the edge of the tip, the toner on the surface of the collecting roller is removed from the contact portion between the scraping blade and the collecting roller. It slips through and scrapes poorly.

  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 initial scraping defects.

In order to achieve the above object, the invention of claim 1 comprises a surface-movable cleaning member that electrostatically moves and removes toner on the surface-moving object to its own surface, and a metal material. A surface-movable recovery member that electrostatically moves and recovers the toner on the cleaning member to the surface of the cleaning member, and a metal material, and slidably rubs on the surface of the recovery member. In a cleaning device including a scraping blade for scraping off toner, when the scraping blade is viewed from the axial direction of the recovery member, the scraping blade is in contact with the surface of the recovery member from the initial use of the scraping blade. A damming stopper that dams the toner on the surface of the collecting member adjacent to the abutting ridge line, facing the collecting member surface with a slight gap, or contacting the collecting member surface. Are those having a upper Symbol cleaning member, and the toner collecting member, and a said toner scraping member, and the normally-charged toner cleaning unit that removes the toner charged to the normal charging polarity on the cleaning element, the A reversely charged toner cleaning unit that includes a cleaning member, the toner collecting member, and the toner scraping member, and that removes toner charged to a polarity opposite to the normal charge polarity on the cleaning target; and the moving direction of the cleaning target The toner, which is disposed at least upstream of the regular charged toner cleaning unit, includes the cleaning member, the toner collecting member, and the toner scraping member, and is charged with a regular charged polarity on the member to be cleaned. And a pre-cleaning section to be removed .
According to a second aspect of the present invention, in the cleaning device according to the first aspect, when the scraping blade is viewed from the axial direction of the recovery member, the scraping blade is provided adjacent to the damming surface and recovered. A blade lower surface facing the member surface; a tip surface provided adjacent to the damming surface and parallel to the thickness direction of the scraping blade; and an angle formed by the blade lower surface and the recovery member surface is 20 °. The scraping blade has an obtuse angle between the damming surface and the lower surface of the blade, and is pulled along the lower surface of the blade when the scraping blade is viewed from the axial direction of the recovery member. The length of the line connecting the intersection of the imaginary line and the imaginary line drawn along the tip surface and the intersection of the tip surface and the damming surface is 8 μm or more and 13 μm or less. It is an butterfly.
According to a third 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 claim 1 or 2 is used as a cleaning device for cleaning residual toner remaining on the image carrier after transfer.
According to a fourth aspect of the present invention, in the image forming apparatus of the third aspect , the image carrier is an intermediate transfer member onto which a plurality of toner images formed on the latent image carrier are sequentially superimposed and transferred. It is characterized by.
According to a fifth 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 claim 1 or 2 is used as a cleaning device for cleaning toner remaining on the transport belt for transporting the recording material.
According to a sixth aspect of the present invention, in the image forming apparatus according to any of the third to fifth aspects, a toner having a shape factor SF1 of 100 or more and 150 or less is used as the toner.

  The toner slipping from the contact portion between the scraping blade and the collecting member does not occur when used to some extent. The present inventors pay attention to this point, and when the tip part contacting the recovery member of the scraping blade when no defective cleaning occurs after being used to some extent, it is worn out. , In contact with the surface of the recovery member. Therefore, the scraping blade abuts against the recovery member with a certain width in the direction of movement of the recovery member, so that the toner slipping from the contact portion between the scraping blade and the recovery member can be suppressed. I found it. Even if there are gaps on the upstream and downstream sides of the recovery member surface movement direction from the tip ridge, if the gap on the upstream or downstream side is as follows, the tip ridge is wavy. In addition, toner slip-through is suppressed. That is, the gap on the upstream side or downstream side of the tip ridge is a slight gap where it is difficult for toner to pass through between the collecting member and the scraping blade, and this gap has a certain width in the movement direction of the collecting member surface. It is a gap that has Accordingly, the present invention provides a recovery member that is adjacent to the tip ridge line portion that comes into contact with the surface of the recovery member from the initial stage of use of the scraping blade and is opposed with a slight gap or in contact with the surface of the recovery member. A blocking surface for blocking the toner on the surface was provided. As a result, in the initial stage of use of the scraping blade, a slight gap between the recovery member surface and the scraping blade is formed to a certain extent in the recovery member surface movement direction next to the recovery member surface movement direction of the tip ridge line portion. The Alternatively, at the initial stage of use of the scraping blade, the scraping blade comes into contact with the collecting member with a certain width in the moving direction of the collecting member. As a result, in order for the toner to slip through the contact portion between the scraping blade and the collecting member, a slight amount of the damming surface that is in contact with the collecting member of the scraping blade or the surface of the collecting member and the damming surface Since the gap is passed through, it becomes difficult to pass through between the scraping blade and the recovery member. Therefore, scraping defects at the initial use of the scraping blade are suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the scraping defect at the time of initial use of a scraping blade can be suppressed.

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 showed the principal part of the belt cleaning apparatus. (A) is sectional drawing of the urethane rubber blade of a free state. FIG. 4B is a cross-sectional view of the urethane rubber blade during toner cleaning of the surface to be cleaned. The schematic block diagram around the conventional pre-scraping blade. The figure which observed the state of the front-end | tip ridgeline part of the pre-scraping blade after performing 100k sheet passing with a microscope. The schematic block diagram of the use initial shape of the front scraping blade front-end | tip part of this embodiment. (A) is a figure which shows the mode of contact | abutting to the pre collection | recovery roller surface of the formed pre-scraping blade by adjusting etching time. (B) is an enlarged view of the contact portion between the pre-scraping blade and the pre-collection roller surface. (A) is a figure which shows the mode of the contact part of the pre scraping blade and the pre collection | recovery roller surface when the distance H is short. (B) is a figure which shows the mode of the contact part of the pre scraping blade and the pre collection | recovery roller surface when the said distance H is long. The schematic block diagram of the periphery of the pre-scraping blade of the belt cleaning apparatus of the modification 1. The schematic diagram explaining the maximum diameter MXLNG and the planar area AREA of the projection image with respect to the two-dimensional plane of a toner particle. FIG. 4 is a schematic diagram for explaining a peripheral length PERI and a planar 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 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 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 neutralization device (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.

  Further, the three cleaning facing rollers 13, 14, 15 disposed inside the belt loop are connected to the brush rollers 101, 104, 107 of the belt cleaning device 100 disposed outside the belt loop, and the intermediate transfer belt 8. Is sandwiched. As a result, a cleaning nip is formed in which the front surface of the intermediate transfer belt 8 and the 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 the surface of the intermediate transfer belt 8 with a solid lubricant 202 such as a zinc stearate lump and a lubricant powder that comes into contact with the solid lubricant and is scraped off from the solid lubricant by rotation. And a coating brush roller 201 as a member.

  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, 5M, 5C, and 5K. During this development, the value of the developing bias applied to the Y, M, C, and K developing rollers is gradually increased. By such development, gradation pattern images of Y, M, C, and K are formed on the photoreceptors 1Y, 1M, 1C, and 1K. These are primarily transferred so as to be arranged at a predetermined interval in the main scanning direction of the intermediate transfer belt 8. At this time, the toner adhesion amount of the toner patch in the gradation pattern of each color is about 0.1 [mg / cm ² ] at the minimum and 0.55 [mg / cm ² ] at the maximum, and the toner Q / d distribution When measured, it is almost aligned with the regular charging polarity.

  Each toner pattern (Sk, Sm, Sc, Sy) formed on the intermediate transfer belt 8 passes through a position facing the optical sensor 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. Specific description will be given below.

FIG. 4 is an enlarged configuration diagram illustrating the belt cleaning device 100 and its surroundings, which are characteristic features of the printer, and FIG. 5 is a schematic configuration diagram illustrating a main part of the belt cleaning device 100. .
4 and 5, the belt cleaning apparatus 100 includes a pre-cleaning unit 100a for roughly removing a toner image that has not been transferred on the intermediate transfer belt 8, and a normal charging polarity (negative polarity) on the intermediate transfer belt 8. A polarity control unit 100b that controls the polarity of the reversely charged toner charged to the opposite polarity (positive polarity) to the normal charged polarity, and a normally charged toner cleaning unit that removes the normally charged toner charged to the normally charged polarity on the intermediate transfer belt 8. 100c.

  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 regular charging 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 this belt cleaning apparatus 100, the voltage applied to the pre-cleaning brush roller 101, the amount of biting into the intermediate transfer belt 8 and the linear velocity so that 90% of the untransferred toner image is removed by the pre-cleaning brush roller 101. Etc. are set.

  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 polarity control unit 100b is disposed on the downstream side of the pre-cleaning unit 100a in the moving direction of the intermediate transfer belt 8, and is negatively charged to the reversely charged toner charged to the opposite polarity (positive polarity) to the normal charging polarity (negative polarity) of the toner. A polarity control brush roller 104 is provided as polarity control means for applying charge and controlling the polarity to the normal charging polarity (negative polarity). The polarity control brush roller 104 also has a function as a reversely charged toner cleaning member that collects reversely charged toner. Then, a reversely charged toner collecting roller 105 serving as a reversely charged toner collecting member for collecting a small amount of the reversely charged toner adhering to the polarity control brush roller 104, and contacting the reversely charged toner collecting roller 105 to remove the reversely charged toner from the roller surface A reversely charged toner scraping blade 106 as a reversely charged toner scraping member for scraping is provided. A negative polarity voltage is applied to the polarity control brush roller 104, and a negative polarity voltage greater than that of the polarity control brush roller 104 is applied to the reversely charged toner collection roller 105.

  The normal charging toner cleaning unit 100c is disposed downstream of the polarity control unit 100b in the moving direction of the intermediate transfer belt 8, and is a normal charging toner cleaning member that electrostatically removes normal charging toner charged to the normal charging 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.

  As shown in FIG. 4, the precleaning unit 100 a and the polarity control 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. Yes. By partitioning the pre-cleaning unit 100a and the polarity control unit 100b with the first insulating seal member 112, a discharge occurs between the pre-cleaning brush roller 101 and the polarity control brush roller 104, or the polarity control unit 100b removes it. It is possible to prevent the toner that has been deposited from reattaching to the pre-cleaning brush.

  Further, the polarity control unit 100 b and the regular charged toner cleaning unit 100 c are partitioned by a second insulating seal member 113, and the second insulating seal member 113 is in contact with the polarity control brush roller 104. By partitioning the polarity control unit 100b and the regular charging toner cleaning unit 100c by the second insulating seal member 113, a discharge is generated between the polarity control brush roller 104 and the regular charging toner cleaning brush roller 107, or regular charging is performed. It is possible to prevent the toner removed by the toner cleaning unit 100c from reattaching to the polarity control 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 polarity control 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 apparatus 100, the toner removed by the polarity control unit 100b and the normally charged toner cleaning unit 100c is stored in the waste toner case 115, but the configuration is not limited thereto. For example, a conveying member that conveys toner to the conveying screw 110 is provided at the bottom of the belt cleaning device 100, or the bottom is inclined to the conveying screw 110 and is removed by the polarity control unit 100b and the regular charged toner cleaning unit 100c. The transferred toner 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 is provided for transporting the toner removed by the polarity control unit 100b and the regular charged toner cleaning unit 100c to a waste toner tank (not shown) provided in the main body of the image forming apparatus. Also good.

  Each of the brush rollers 101, 104, and 107 includes a metal rotating shaft member that is rotatably supported and a brush portion that includes a plurality of raised brushes that are erected on the peripheral surface of the rotating shaft member. Is φ15 to 16 [mm]. The raised nail has a two-layer core-sheath structure in which the inside is made of a conductive material such as conductive carbon and the surface portion is made of an insulating material such as polyester. As a result, the lead has substantially the same potential as the voltage applied to the brush roller, and the toner can be electrostatically attracted to the raised surface. As a result, the toner on the intermediate transfer belt 8 is electrostatically attached to the brush fibers by the action of the voltage applied to the brush roller. Moreover, you may comprise the brush fiber of each brush roller 101,104,107 only with a conductive fiber. Moreover, you may make it the so-called oblique hair planted in the attitude | position inclined with respect to the normal line direction of a rotating shaft member. Alternatively, the brush fibers of the pre-cleaning brush roller 101 and the normally charged toner cleaning brush roller 107 may have a core-sheath structure, and the brush fibers of the polarity control brush roller 104 may be formed of only conductive fibers. By configuring the brush fibers of the polarity control brush roller 104 only with conductive fibers, charge injection from the polarity control brush roller 104 to the toner is likely to occur. Therefore, the polarity control brush roller 104 can satisfactorily align the toner on the intermediate transfer belt 8 with negative polarity. On the other hand, the core fibers of the pre-cleaning brush roller 101 and the regular charged toner cleaning brush roller 107 have a core-sheath structure, so that the charge injection into the toner can be suppressed, and the toner on the intermediate transfer belt 8 becomes positive. Suppresses charging. Thereby, it is possible to prevent the pre-cleaning brush roller 101 and the normally charged toner cleaning brush roller 107 from generating toner that cannot be removed electrostatically.

  Further, each of the brush rollers 101, 104, and 107 bites into the intermediate transfer belt 8 by 0.7 to 1.5 [mm], and the brush is brought into contact with the intermediate transfer belt 8 by a driving unit (not shown). It rotates to move in the direction opposite to the direction of movement (counter direction). By rotating the brush so as to move in the counter direction at the contact portion, the relative speed of the brush roller with respect to the intermediate transfer belt 8 can be increased at the contact portion. As a result, the probability of contact with the brush before a portion of the intermediate transfer belt 8 passes through the contact range with the brush roller increases, and the toner can be removed from the intermediate transfer belt 8 satisfactorily.

  In the belt cleaning apparatus 100, SUS rollers are used as the collecting rollers 102, 105, and 108. Each of the collecting rollers 102, 105, and 108 may be made of any material as long as it can perform the function of transferring the toner adhering to the brush roller from the brush to the collecting roller by the potential gradient between the raised brush and the collecting roller. Absent. For example, each of the collecting rollers 102, 105, and 108 is covered with a high resistance elastic tube of several [μm] to 100 [μm] on a conductive core metal or further coated with an insulating coating, and the roller resistance is set to log R = 12 to You may use what was 13 [(ohm)]. By using a SUS roller as each of the collection rollers 102, 105, 108, there is an advantage that the cost can be reduced, the applied voltage can be kept low, and the power can be saved. On the other hand, by setting the roller resistance to logR = 12 to 13 [Ω], the charge injection into the toner during the collection to the collection roller is suppressed, and the toner has the same polarity as the applied voltage of the collection roller. It can suppress that a recovery rate falls.

  Each of the brush rollers 101, 104, and 107 and the cleaning counter rollers 13, 14, and 15 are φ14 [mm] aluminum rollers that are driven to rotate by the frictional force between the intermediate transfer belt 8 and its surface. The cleaning counter rollers 13, 14, and 15 are connected to the ground.

The conditions of each brush roller 101, 104, 107 are as follows.
・ Brush material: Conductive polyester (Contains conductive carbon inside the fiber, the fiber surface is polyester, so-called core-sheath structure)
・ Brush resistance: 10 ^6-8 [Ω]
・ Rotary shaft member applied voltage [V]
Pre-cleaning brush roller: + 1600-2000 [V]
Polarity control brush roller: -2000 to -2400 [V]
Regularly charged toner cleaning brush roller: 800 to 1200 [V]
・ Brush flock density: 100,000 [lines / inch2]
・ Brush fiber diameter: about 25 to 35 [μm]
-Brush tipping treatment at the brush tip: Yes-Brush diameter φ: 15-16 [mm]
-Brush fiber biting amount into the intermediate transfer belt 8: 1 [mm]
The applied voltage to the pre-cleaning brush roller 101 is set so that good cleaning performance can be obtained when an untransferred toner image having a large amount of toner attached to the intermediate transfer belt 8 is input. In addition, the polarity control brush roller 104 is set high so that electric charge is injected into the toner on the intermediate transfer belt 8. Further, the brush flocking density, brush resistance, fiber diameter, applied voltage, fiber type, and brush fiber biting amount can be optimized by the system, and thus are not limited thereto. Examples of the types of fibers that can be used include nylon, acrylic, and polyester.

The conditions of each collection roller 102, 105, 108 are as follows.
・ Recovery roller core material: SUS
・ Collecting roller cored bar voltage:
Pre-collection roller: 2000 to 2400 [V]
Reversely charged toner collection roller: -2400 to -2800 [V]
Regularly charged toner collecting roller: +1000 to +1400 [V]
The collection roller material, brush fiber entrapment amount, and applied voltage can be optimized by the system, and are not limited thereto.

The conditions of each scraping blade 103, 106, 109 are as follows.
・ Blade contact angle: 20 °
・ Blade thickness: 0.1 [mm]
・ Blade biting amount into collection roller: 1.0 [mm]
The blade contact angle, the blade thickness, and the amount of biting into the collection roller can be optimized by the system, and are not limited thereto.

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 polarity control brush roller 104. A voltage having the same polarity (negative polarity) as the normal charging polarity of the toner is applied to the polarity control brush roller 104, and the polarity of the toner on the intermediate transfer belt 8 is made negative by charge injection or discharge. At the same time, the positively charged reversely charged toner on the intermediate transfer belt 8 is electrostatically adsorbed by the electric field formed by the potential difference between the intermediate transfer belt 8 and the surface potential of the polarity control brush roller 104. Move to the polarity control brush roller 104. The positive polarity reversely charged toner that has moved to the polarity control brush roller 104 is transferred to a contact position with the reverse charge toner collection roller 105 to which a negative voltage having a larger value than the polarity control brush roller 104 is applied. Then, the reversely charged toner moved onto the polarity control brush roller 104 is electrostatically adsorbed by the electric field formed by the potential difference between the surface potential of the polarity control brush roller 104 and the surface potential of the reversely charged toner collecting roller 105. The toner is moved onto the reversely charged toner collecting roller 105. The positively charged reversely charged 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 toner shifted to the negative polarity by the polarity control brush roller 104 and the negative polarity toner that could not be removed by the pre-cleaning brush roller 101 are transferred to the regular charged toner cleaning brush roller 107. The polarity of the toner transferred to the normally charged toner cleaning brush roller 107 is negatively controlled by the polarity control brush roller 104. Further, the toner on the intermediate transfer belt 8 is almost removed by the pre-cleaning brush roller 101 and the polarity control 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 aligned with the negative polarity transferred to the normally charged toner cleaning brush roller 107 is applied with a voltage having a polarity (positive polarity) opposite to the normal charged polarity of the toner. The toner is electrostatically attached to the regular charged toner cleaning brush roller 107, collected by the regular charged toner collection roller 108, and scraped off from the regular charged toner collection roller 108 by the regular 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 polarity control brush roller 104 and the normally charged toner cleaning brush roller 107 can be reduced. The toner on the intermediate transfer belt transferred to the normally charged toner cleaning brush roller 107 at the most downstream side in the belt moving direction is not removed by the pre-cleaning brush roller 101 and the polarity control brush roller 104. Very small amount. Further, the toner has a negative polarity by the polarity control brush roller 104. 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 brush rollers 101, 104, and 107.

  Further, the polarity control unit 100b may be configured not to remove the positive toner on the intermediate transfer belt 8, and the reversely charged toner collecting roller and the reversely charged toner scraping blade may be omitted. In this case, the positive toner adhering to the polarity control brush roller 104 receives charge injection from the polarity control brush roller 104, reverses the polarity to the negative polarity, and then reattaches to the intermediate transfer belt 8 to be normally charged toner. It is removed by the cleaning brush roller 107. In the configuration of the first modification, the amount of toner input to the regular charged toner cleaning brush roller 107 is increased, but the layout is simplified because the reverse charged toner collecting roller 105 and the reverse charged toner scraping blade 106 are not provided. Is cheaper. In addition to the polarity control brush roller 104, a conductive blade, a corona charger, or the like may be used as means for injecting negative charge into the toner on the intermediate transfer belt 8. Further, a cleaning brush roller to which a negative voltage is applied is arranged downstream of the polarity control unit 100b in the belt moving direction so that the charging polarity of the toner is not equal to the negative polarity but the positive polarity. In addition, 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 100b is reduced. Therefore, the polarity control unit 100b 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 and electrostatically removed by the cleaning brush roller disposed downstream of the polarity control unit 100b. 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.

  In addition, the belt cleaning device 100 is replaced with a polarity control unit 100b, which is a reversely charged toner cleaning unit that removes reversely charged toner from the intermediate transfer belt 8, and controls the toner polarity on the intermediate transfer belt to have a negative polarity. The structure which does not perform may be sufficient.

  In the belt cleaning apparatus 100, a voltage is applied to each of the collecting rollers 102, 105, and 108 and each of the brush rollers 101, 104, and 107. The collecting rollers 102, 105, and 108 are used as metal rollers, and are collected. A configuration in which a voltage is applied only to the roller may be used. In this case, due to the potential drop due to the fiber resistance of the brush roller, a bias voltage slightly lower than the bias voltage applied to the collecting roller is applied to the brush roller in a form through the contact portion with the collecting roller. Become. Thereby, a potential difference is formed between the collection roller and the brush roller, and the toner can be electrostatically moved from the brush roller to the collection roller by a potential gradient in the direction of the collection roller.

Next, features of the present embodiment will be described.
A metal blade is used as each scraping blade in this embodiment.
6A is a cross-sectional view of the urethane rubber blade 1000 in a free state, and FIG. 6B is a cross-sectional view of the urethane rubber blade 1000 during toner cleaning of the surface 1002 to be cleaned.
As shown in FIG. 6A, the urethane rubber blade 1000 has a strip shape when in a free state. When the urethane rubber blade 1000 is brought into contact with the surface to be cleaned 1002, the tip edge line portion 1001 of the urethane rubber blade 1000 is brought into contact with the surface to be cleaned 1002. At the time of cleaning the surface to be cleaned, as shown in FIG. 6, the tip ridge line portion 10001 is elastically deformed in the moving direction of the surface to be cleaned, and a part of the blade tip surface 1003 on the tip ridge line portion side comes into contact with the surface to be cleaned. . Thereby, in the case of the urethane rubber blade 1000, in the initial stage of use, the urethane rubber blade 1000 comes into surface contact with the surface to be cleaned with a certain width in the moving direction of the surface to be cleaned.

  However, the urethane rubber blade 1000 has the following problems. That is, in the image forming apparatus of the present embodiment, spherical toner is used as will be described later, and the toner easily slips through the contact portion between the blade 1000 and the surface to be cleaned 1002. In order to suppress such slip-through, it is necessary to increase the contact pressure between the surface to be cleaned 1002 and the urethane blade 1000 to enhance the cleaning ability (scraping ability) of the urethane blade 1000. However, when the contact pressure of the urethane blade 1000 is increased, the frictional force between the surface to be cleaned 1002 and the urethane blade 1000 is increased, and the urethane blade 1000 is pulled in the moving direction of the surface to be cleaned 1002, so Part 1001 turns over. When the turned-up urethane blade 1000 is restored to its original shape against the turning-up, abnormal noise may occur. Further, if the cleaning is continued with the leading edge portion 1001 of the urethane blade 1000 turned up, local wear occurs at a location several [μm] away from the leading edge portion 1001 of the leading edge surface 1003 of the urethane blade. If the cleaning is further continued in such a state, this local wear increases, and the leading edge line portion 1001 is eventually lost. If the leading edge portion 1001 is missing, the toner cannot be properly cleaned, resulting in poor cleaning.

  Thus, when a urethane blade is used as the scraping blade, the tip ridge line portion is turned up, which is not preferable. On the other hand, when a metal blade is used as the scraping blade, the above-described tip ridge line portion is not turned up and wear is small. Therefore, the toner on the surface of the collection roller can be removed well over a longer period than the urethane blade.

FIG. 7 is a schematic configuration diagram around a conventional pre-scraping blade.
The pre-scraping blade 103 made of a metal blade is fixed to the holder 122 with an adhesive 121, and the tip edge line portion 103 a of the pre-scraping blade is brought into contact with the surface of the pre-collecting roller 102. The configuration around the reversely charged toner scraping blade 106 and the configuration around the regular charged scraping blade 106 are the same as those in FIG. 7, and the tip edge line portion of the scraping blade is brought into contact with the surface of the collecting roller. Since the configuration of each scraping blade is the same, the following description will be made using a pre-scraping blade.

  As the pre-scraping blade 103, a metal blade is used, and the initial shape of the pre-scraping blade 103 is a strip shape like the urethane rubber blade as shown in FIG. 6A, and the pre-scraping blade 103 is pre-scraped as shown in FIG. When the leading edge line 103a of the take-up blade 103 is brought into contact with the surface of the pre-collection roller 102, an initial scraping failure occurs. This is because the pre-recovery roller 102 is a metal roller and the pre-scraping blade 103 is a metal blade, so that they do not elastically deform each other. Therefore, when the pre-scraping blade 103 is brought into contact with the pre-collecting roller 102, only the tip edge line portion 103a of the pre-scraping blade 103 comes into contact with the pre-collecting roller 102. Line contact is made with respect to the collection roller 102. As described above, since the line contact occurs, if the tip edge line portion 103a of the pre-scraping blade 103 has waviness or the like, the toner slips through, resulting in poor scraping. Such a scraping failure of the pre-scraping blade 103 is only at the initial stage, and when used over time, the toner on the surface of the pre-collecting roller 102 can be scraped well.

FIG. 8 is a view of the state of the tip ridge portion 103a of the pre-scraping blade 103 after passing 100k sheets, observed with a microscope (Keyence VK8500). (A) is a conceptual diagram when the pre-scraping blade 103 is observed from the axial direction of the pre-collecting roller 102, and (b) is a diagram when the pre-scraping blade 103 is observed from the direction A in FIG. It is. Further, when 100 k sheets were passed, no scraping failure of the pre-scraping blade 103 was confirmed.
Referring to FIG. 8, the tip edge line portion 103 a of the pre-scraping blade 103 is not worn, and the wear surface X of the pre-scraping blade 103 is in contact with the pre-collecting roller 102 and the surface. Thus, the scraping failure of the pre-scraping blade 103 is suppressed by the wear surface X of the pre-scraping blade 103 coming into contact with the pre-collecting roller 102. Therefore, by providing such a wear surface X on the pre-scraping blade 103 from the initial stage of use, it is possible to suppress scraping defects at the initial stage of use of the pre-scraping blade.

FIG. 9 is a schematic configuration diagram of an initial use shape of the tip portion of the pre-scraping blade of this embodiment.
As shown in FIG. 9, the pre-scraping blade 103 according to the present embodiment has an initial shape such that it faces the pre-recovery roller surface with a slight gap between the blade lower surface 103b and the tip surface 103c, or pre-recovery. A damming surface 103d that dams the toner on the surface of the pre-collecting roller is provided so as to contact the roller surface. Further, an angle θ1 formed by the blade lower surface 103b and the damming surface 103d is an obtuse angle.
Such a blocking surface 103d is formed as follows. The pre-scraping blade 103 is formed by performing etching on a sheet metal and cutting it, but it can be formed by changing the etching time.
The above etching process is performed by masking a portion other than the cut portion on the front surface and the back surface of the sheet metal, cutting the sheet metal by performing an etching process from both the front surface side and the back surface side of the sheet metal, A pre-scraping blade 103 is formed. Then, the above-mentioned facing / contacting surface 103d is formed by making the etching time performed from the surface of the pre-scraping blade of the sheet metal to be the blade lower surface 103b shorter than the etching time performed from the opposite surface. can do.

FIG. 10A is a diagram showing a state in which the pre-scraping blade 103 formed is brought into contact with the surface of the pre-collecting roller 102 by adjusting the etching time, and FIG. FIG. 6 is an enlarged view of a contact portion between the take-up blade 103 and the pre-collection roller 102 surface.
As shown in the figure, in this configuration, in the initial stage of use, the side D1 is a tip ridge line portion that contacts the surface of the pre-collection roller 102, and the damming surface 103d is pre-collected more than the tip ridge line portion D1. It is formed on the upstream side of the roller surface movement direction. The damming surface 103d forms a slight gap on the upstream side in the pre-collection roller surface movement direction with respect to the leading edge line portion D1, and this gap has a certain width in the pre-collection roller surface movement direction. When the apparatus was driven with the above-described configuration, no initial scraping failure occurred. As shown in the enlarged view of FIG. 10B, the gap between the blocking surface 103d and the pre-collection roller 102 is very small, and the toner does not enter the slight gap. The tip surface 103c is scraped off by the side D2, which is one side. Even if the side D2 has a slight undulation, the toner does not enter a slight gap between the facing and abutting surfaces 103d. Therefore, toner does not slip between the pre-scraping blade 103 and the pre-collection roller 102 even if the facing / contact surface 103 d is not in contact with the surface of the pre-collection roller 102 in this way. Therefore, the scraping failure at the initial use of the pre-scraping blade 103 can be suppressed.

  Further, as shown in FIG. 9, the distance H from the intersection K between the virtual line drawn along the blade lower surface 103b and the virtual line drawn along the tip surface to the side D2 of the tip surface 103c is too short. However, if it is too long, the effect of suppressing the initial scraping failure cannot be obtained.

FIG. 11A is a diagram showing a state of a contact portion between the pre-scraping blade 103 and the surface of the pre-collecting roller 102 when the distance H is short, and FIG. It is a figure which shows the mode of the contact part of the pre scraping blade 103 and the pre collection | recovery roller 102 surface when long.
As shown in FIG. 11 (a), when the distance H is short, the side D2 becomes a tip ridge line portion that comes into contact with the surface of the pre-collection roller 102, and the damming surface 103d moves on the collection roller surface more than the tip ridge line portion. Located downstream in the direction. When the distance H is short, a gap between the damming surface 103d and the pre-collection roller 102 becomes large. As a result, when there is a undulation in the tip ridge line portion D2, the toner cannot be dammed in the gap on the downstream side of the tip ridge line portion D2, and slips between the pre-scraping blade 103 and the pre-collection roller 102. Therefore, the initial scraping failure cannot be suppressed.
Further, as shown in FIG. 11B, when the distance H is long, the side D1 becomes a tip ridge line portion that comes into contact with the pre-collection roller 102, and the damming surface 103d is more pre-collection roller than the tip ridge line portion. Located upstream in the direction of movement. If the distance H is too long, a gap between the damming surface 103d and the pre-collection roller 102 becomes large. As a result, the toner cannot be dammed up in the gap upstream of the tip ridge line portion D1, and the toner moves to the tip ridge line portion D1, and scrapes off the toner at the tip ridge line portion D1. Therefore, if there is a undulation in the tip ridge line portion D1, it slips between the pre-scraping blade 103 and the pre-collecting roller 102, and the initial scraping failure cannot be suppressed.

Table 1 shows the results of examining the relationship between the distance H and the initial scraping failure.
The conditions of the pre-collection roller 102 and the pre-scraping blade 103 at this time are shown below.
-Pre-collection roller conditions-Collection roller core metal material: SUS303-G8
・ Diameter: Φ13 ± 0.05
-Surface Ra: 0.4
・ Pre-scraping blade conditions ・ Blade material: SUS304 H material (manufactured by Shin-Etsu Polymer)
・ Blade contact angle: 20 °
・ Blade thickness: 0.1 [mm]
・ Blade biting amount into pre-collection roller: 1.0 [mm]
-Average particle diameter of toner: 5.2 [μm]
The amount of blade biting into the pre-collection roller is the amount of biting when it is assumed that the pre-scraping blade 103 penetrates without contacting the surface of the pre-collection roller 102.

  As shown in Table 1, when the distance H was 8 μm or more and 13 μm or less, the initial scraping failure did not occur. On the other hand, when the distance H was less than 8 μm, an initial scraping failure occurred. This is because when the distance is less than 8 μm, the gap between the blocking surface 103d and the pre-collection roller 102 is large, and the toner cannot be blocked by the gap between the blocking surface 103d and the pre-collection roller 102. It is considered that an initial scraping failure occurred. On the other hand, when the distance H is 8 to 13 μm, a gap formed by the damming surface 103 d and the surface of the pre-collection roller 102 is not more than a toner particle size (5.2 μm) or less in the moving direction of the surface of the pre-collection roller 102. It is thought that it is formed with a width of. Therefore, it is considered that the toner was blocked by the gap between the blocking surface 103d and the surface of the pre-collection roller 102, and the initial scraping failure could be suppressed.

  Further, as a result of investigating the relationship between the angle θ1 between the blade lower surface 103b and the damming surface 103d and the initial scraping failure, θ1 suppresses the initial scraping failure at an angle of (90 ° + blade contact angle) or more. I knew it was possible.

  Although the pre-scraping blade 103 has been described above, the initial shape of the reversely charged toner scraping blade 106 and the regular charged toner scraping blade 109 is changed to the initial shape shown in FIG. Scraping defects can be suppressed.

  Next, a modified example of the belt cleaning device 100 will be described.

[Modification 1]
FIG. 12 is a schematic configuration diagram around the pre-scraping blade 103 of the belt cleaning device of the first modification. As shown in FIG. 12, in this modification, the holder 122 is grounded via a switch 123.
In the first modification, the pre-scraping blade 103 has a strip shape, like the urethane rubber blade shown in FIG. 6A, before the device is attached, and no damming surface 103d is formed. . A conductive agent having a resistance of 100Ω and a particle size of 5 μm is applied to the periphery of the tip ridge line portion 103a of the pre-scraping blade 103 before the device is attached. Examples of the conductive agent include carbon-dispersed acrylic resin. After such a pre-scraping blade 103 is set in the apparatus main body as shown in FIG. 12, the switch 123 is turned ON. Then, the pre-collection roller 102 is rotated while applying a voltage to the pre-collection roller 102. Then, discharge occurs between the pre-collection roller 102 and the periphery of the tip ridge line portion 103a to which the conductive agent of the pre-scraping blade 103 is applied, and a current flows. By the discharge energy at this time, the periphery of the tip ridge line portion 103a is oxidized, and the wear of the tip ridge line portion 103a is accelerated. When the damming surface 103d as shown in FIG. 9 is formed on the pre-scraping blade 103, the switch 123 is turned off. When the switch 123 is turned OFF, no discharge occurs between the pre-collecting roller 102 and the pre-scraping blade 103, and no current flows. Therefore, oxidation of the pre-scraping blade 103 is suppressed, and wear of the pre-scraping blade 103 is prevented. Deterred. When the pre-scraping blade 103 is replaced, the pre-recovery roller 102 is pre-rotated for 1 to 5 minutes, whereby the damming surface 103 d can be formed on the pre-scraping blade 103. Thereafter, a cleaning operation is performed. The damming surface 103 d of this modification 1 comes into contact with the surface of the pre-collection roller 102. Thereby, also in this modified example 1, in the initial stage of use of the pre-scraping blade 103, a damming surface 103d is formed which contacts the pre-scraping blade 103 with a certain amount of width in the moving direction of the pre-recovery roller 102 and the pre-recovery roller surface. Is done. Therefore, the toner can be dammed by the damming surface, and the initial scraping failure can be suppressed.

  In the above description, the shape of the pre-scraping blade 103 before installation of the device is a strip shape. However, the shape of the pre-scraping blade 103 before installation of the device is formed with a blocking surface 103d as shown in FIG. It may be done. By doing so, it is possible to form the damming surface 103 d that contacts the surface of the pre-collecting roller 102 on the pre-scraping blade 103 in a short pre-rotation time.

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. 13 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. 14 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 shape of the toner is close to a spherical shape, the contact state between the toner and the toner or the toner and the photoconductor becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity increases, and the toner and the photoconductor The attraction force becomes weaker and the transfer rate becomes higher. 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-isocyanatomethyl caproate, 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 polyhydric carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxy titanate, 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 elongation reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator may 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. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color image forming apparatus are deteriorated.

  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 the temperature is lower than 45 ° C., the heat resistance of the toner is deteriorated.

  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 PSYVP2038, 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 masterbatch and the binder resin, or may be added when dissolved and dispersed in an 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), MegaFuck F-110, F-
120, F-113, F-191, F-812, F-833 (Dainippon Ink Co., Ltd.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (Manufactured by Tochem Products Co., Ltd.), Footent F-100, F150 (manufactured by Neos), and the like.

  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. 15A, 15B, and 15C are diagrams schematically showing the shape of the toner. 15A, 15B, and 15C, 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. 15B) is 0.5 to 1.0, and the ratio of the thickness to the minor axis (r3 / r2) (FIG. 15C )) 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.

  Further, the cleaning device of the present invention can be applied not only to the belt cleaning device 100 that cleans 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. 16, a paper transport belt 51 as a cleaning object 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. 16, 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, the toner pattern formed on the paper transport belt 51 can be removed satisfactorily, and the back surface of the recording paper is prevented from being stained with toner. can do.

  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, it is possible to satisfactorily remove the untransferred toner image input to the drum cleaning device 4.

  As described above, the belt cleaning device 100 as a cleaning device according to the embodiment is 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 the surface thereof and removes the toner. A cleaning brush roller, a recovery roller made of a metal material, and a recovery roller that is a surface-movable recovery member that electrostatically moves the toner on the cleaning brush roller to the surface of the cleaning brush and recovers the toner. And a scraping blade that scrapes off the toner on the collecting roller by rubbing against the surface. When the scraping blade is viewed from the axial direction of the collecting roller, the scraping blade is adjacent to the tip ridge line portion in contact with the collecting roller surface from the initial stage of use of the scraping blade, and has a slight gap with the collecting roller surface. It has a damming surface that dams the toner on the surface of the collecting roller by facing the surface or contacting the surface of the collecting roller. Thereby, the scraping defect at the initial stage of use can be suppressed.

  In addition, when the scraping blade is viewed from the axial direction of the collecting roller, the scraping blade is provided adjacent to the damming surface, the blade lower surface facing the collecting roller surface, and the scraping blade provided adjacent to the damming surface. The blade has a tip surface parallel to the thickness direction of the take-off blade, the angle between the lower surface of the blade and the surface of the collecting roller (blade contact angle) is 20 °, and the scraping blade has a damming surface and a lower surface of the blade. When the scraping blade is viewed from the axial direction of the collecting roller when the angle θ1 formed by the angle is an obtuse angle, an intersection K between a virtual line drawn along the lower surface of the blade and a virtual line drawn along the tip surface The length of the line connecting the tip surface and the intersection D2 of the damming surface was 8 μm or more and 13 μm or less. As a result, the gap between the damming surface and the collection roller can be made equal to or smaller than the toner particle diameter, and the toner cannot pass through the gap between the damming surface and the collection roller. Therefore, it is possible to suppress scraping defects at the initial use.

A cleaning brush roller and a recovery roller are provided, and a cleaning voltage having a polarity opposite to the normal charging polarity of the toner is applied to the cleaning brush roller to electrostatically remove the toner having the normal charging polarity on the surface of the intermediate transfer belt. A normal charging toner cleaning unit 100c, a cleaning brush roller, and a collection roller are provided, and a cleaning voltage having the same polarity as the normal charging polarity of the toner is applied to the cleaning brush roller to be opposite to the normal charging polarity on the surface of the intermediate transfer belt 8. A reversely charged toner cleaning unit that electrostatically removes polarity toner, a cleaning brush roller, and a collection roller are provided, and upstream of the regular charged toner cleaning unit 100c and the reversely charged toner cleaning unit with respect to the surface movement direction of the intermediate transfer belt. Placed on the cleaning brush roller By applying a regular charging polarity opposite to the polarity of the cleaning voltage of the toner, and a pre-cleaning unit 100a that removes the toner of the normal charging polarity on the intermediate transfer belt surface electrostatically. By providing such a configuration, when an untransferred toner image containing a large amount of toner charged to a normal charge polarity is input to the belt cleaning device 100, the untransferred toner image is roughly set by the cleaning brush roller of the precleaning unit 100a. It is possible to remove the toner charged to the regular charge polarity. As a result, the amount of toner input to the regular charged toner cleaning unit 100c and the reversely charged toner cleaning unit disposed downstream of the pre-cleaning unit 100a in the belt moving direction is reduced. As a result, the toner charged to the regular charge polarity that could not be removed by the pre-cleaning unit 100a can be satisfactorily removed by the cleaning brush roller of the regular charged toner cleaning unit 100c. Further, the charged toner can be satisfactorily removed to the polarity opposite to the normal charging polarity by the cleaning brush roller of the reversely charged toner cleaning unit. Therefore, even if an untransferred toner image is input to the belt cleaning device, the untransferred toner image can be satisfactorily removed from the intermediate transfer belt 8.
Moreover, the initial scraping failure of the scraping blades of the cleaning units 100a, 100b, and 100c can be suppressed.

In addition, a polarity control unit that controls the charging polarity of the toner on the intermediate transfer belt 8, a cleaning brush roller, and a collection roller are provided. The cleaning brush is disposed downstream of the polarity control unit with respect to the surface movement direction of the intermediate transfer belt 8. A cleaning unit that electrostatically removes toner by applying a cleaning voltage opposite to the charging polarity of the toner controlled by the polarity control means to the roller, a cleaning brush roller, and a collection roller are provided. It is disposed upstream of the polarity control means with respect to the surface movement direction, and a cleaning voltage having a polarity opposite to the normal charging polarity of the toner is applied to the cleaning brush roller to electrostatically charge the toner having the normal charging polarity on the surface of the intermediate transfer belt 8. The structure provided with the pre-cleaning part 100a to remove may be sufficient. Even in such a configuration, when a non-transferred toner image containing a large amount of toner charged to the normal charging polarity is input to the belt cleaning device 100, the pre-cleaning brush roller 101 roughly sets the normal charging polarity of the non-transferred toner image. The charged toner can be removed. As a result, the amount of toner input to the polarity control means disposed downstream of the pre-cleaning brush roller 101 in the belt movement direction is reduced. As a result, the polarity of the toner on the intermediate transfer belt 8 can be favorably controlled by the polarity control means. Therefore, it is possible to make the charging polarity of the toner input to the cleaning brush roller disposed downstream of the polarity control means in the belt moving direction uniform. In addition, since the amount of toner input to the cleaning brush roller is small, the toner on the intermediate transfer belt that could not be removed by the pre-cleaning brush roller can be satisfactorily removed by the cleaning brush roller. As a result, even if an untransferred toner image is input to the belt cleaning device, the untransferred toner image can be satisfactorily removed from the intermediate transfer belt.
Further, it is possible to suppress the initial scraping failure of the scraping blade of the pre-cleaning unit and the cleaning unit on the downstream side of the polarity control means.

  In an image forming apparatus for forming an image on a recording paper as a recording material by finally transferring a toner image formed on the image bearing member from the image bearing member onto a recording material, By using the cleaning device as a cleaning device for cleaning the transfer residual toner remaining on the toner, the toner on the image carrier can be cleaned well. Thereby, high-quality image formation can be realized.

  Further, by using the cleaning device of the present invention as the belt cleaning device 100 that cleans the intermediate transfer belt 8 that is an image carrier, the toner on the intermediate transfer belt 8 can be satisfactorily cleaned. Since the toner on the intermediate transfer belt 8 can be cleaned well, high-quality image formation can be realized.

  Also, as shown in FIG. 16, the toner on the paper transport belt 51 is improved by using the cleaning device of the present invention as the transport belt cleaning device 500 for cleaning the toner remaining on the transport belt for transporting the recording paper. Can be cleaned. Thereby, it can suppress that the back surface of a recording paper becomes dirty with a toner.

1: Photoconductor 4: Drum cleaning device 8: Intermediate transfer belt 51: Paper transport belt 100: Belt cleaning device 100a: Pre-cleaning unit 100b: Polarity control unit 100c: Regularly charged toner cleaning unit 101: Pre-cleaning brush roller 101 Brush roller 102: Pre-collection roller 103: Pre-scraping blade 103a: Tip edge 103b: Blade lower surface 103c: Tip surface 103d: Opposing / contacting surface 104: Polarity control brush roller 105: Reverse charging toner recovery roller 106: Reverse charging Toner scraping blade 107: Regularly charged toner cleaning brush roller 108: Regularly charged toner collecting roller 109: Regularly charged toner scraping blade 500: Conveying belt cleaning device 500 Conveying belt cleaning device

JP 2006-58422 A

Claims (6)

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 is made of a metal material and electrostatically moves and recovers the toner on the cleaning member to its own surface;
In a cleaning device comprising a metal material, and a scraping blade that scrapes off the toner on the recovery member by rubbing against the surface of the recovery member,
When the scraping blade is viewed from the axial direction of the recovery member, the scraping blade is adjacent to the tip ridge line portion that contacts the recovery member surface from the initial stage of use of the scraping blade, and is slightly different from the recovery member surface. It has a damming surface that dams the toner on the surface of the collecting member by facing the gap or contacting the surface of the collecting member ,
A regular charged toner cleaning unit that includes the cleaning member, the toner collecting member, and the toner scraping member, and that removes toner charged to a regular charged polarity on the object to be cleaned;
A reversely charged toner cleaning unit that includes the cleaning member, the toner collecting member, and the toner scraping member, and that removes toner charged to a polarity opposite to the normal charge polarity on the object to be cleaned;
With respect to the moving direction of the cleaning target, the cleaning unit is disposed at least upstream of the regular charging toner cleaning unit, and includes the cleaning member, the toner recovery member, and the toner scraping member, and includes a normal charging on the cleaning target. A cleaning device comprising: a pre-cleaning unit that removes toner charged to a polarity . The cleaning device according to claim 1.
When the scraping blade is viewed from the axial direction of the collecting member, the scraping blade is provided adjacent to the damming surface and is opposed to the surface of the collecting member and is adjacent to the damming surface. A tip surface parallel to the thickness direction of the scraping blade provided,
The angle between the blade lower surface and the recovery member surface is 20 °,
The scraping blade has an obtuse angle formed by the damming surface and the lower surface of the blade, and an imaginary line drawn along the lower surface of the blade when the scraping blade is viewed from the axial direction of the collecting member. The length of the line connecting the intersection of the virtual line drawn along the tip surface and the intersection of the tip surface and the damming surface is 8 μm or more and 13 μm or less. Equipment . 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,
An image forming apparatus using the cleaning device according to claim 1 or 2 as a cleaning device for cleaning residual toner remaining on the image carrier after the transfer. The image forming apparatus according to claim 3 .
The image forming apparatus, wherein the image carrier is an intermediate transfer member to which a plurality of toner images formed on the latent image carrier are sequentially superimposed and transferred. 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,
An image forming apparatus using the cleaning device according to claim 1 or 2 as a cleaning device for cleaning toner remaining on a transport belt for transporting the recording material. The image forming apparatus according to any one of claims 3 to 5 ,
An image forming apparatus using a toner having a shape factor SF1 of 100 or more and 150 or less as the toner.