JP2011232477A - Belt device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt device for direct transfer which is miniaturized at a low cost and solves damage at end of the belt caused by a meandering and running over of the belt while reducing greatly toner scattering and preventing an inside of the device from getting dirt, and to provide an image forming apparatus with the belt device mounted.SOLUTION: A transfer cleaning part whose width is greater than the width of photoreceptor cleaning is disposed. And a belt holding member 67 is disposed inside the ends of the transfer cleaning in a thrust direction on the upstream roller upper stream side from the picture forming part 20.

Description

  The present invention relates to an image forming apparatus using a conveyance belt that conveys a recording member to which a toner image is transferred by being used for image formation of a copying machine, a printer, a FAX, or the like.

In a transfer apparatus having a conveyance belt that conveys a recording member such as recording paper, transfer paper, and a plastic sheet, when tension is applied to the conveyance belt, a tension roller is attached to secure the tension.
However, there is a problem that the end of the belt is damaged by the meandering and running of the conveyor belt due to spring tolerance, component tolerance, and mounting variation of the transfer device itself. Therefore, in order to ensure the transportability of the transport belt, it is already known that a method of attaching a bead inside the transport belt, a method of mounting a pressing member on the belt surface, and a method of correcting the meandering of the belt are taken. Yes.
However, with conventional bead mounting methods, productivity problems such as damaging the belt when a bead is attached to the belt, and image defects due to bead shaving powder getting inside the belt, etc. was there.
Further, in the method of attaching the pressing member to the belt surface, the toner leaking from the end of the photosensitive member cleaning member adheres to the pressing member and is scattered when a certain amount is reached, and the inside of the image forming apparatus is contaminated. is there. In order to solve the problem, it is necessary to arrange the pressing member outside the image forming area, and there is a problem that the size of the machine main body is increased.
Furthermore, the meandering correction mechanism method has a problem that the cost increases because the correction mechanism is configured.

In Patent Document 1, a belt member including at least one guide member that regulates meandering of the belt on the inner peripheral surface side of the conveyor belt, a plurality of rollers including a guide portion that guides the guide member, and a plurality of rollers A belt unit that has at least one drive unit and is configured to rotate and move the belt member around the plurality of rollers. Provided are a belt unit capable of suppressing meandering of a belt by providing a pressing member that presses a guide member from the side, and an image forming apparatus including the belt unit.
However, when a direct transfer apparatus is used, the problem that the main body size becomes large cannot be solved because it must be arranged outside the image forming area.

Patent Document 2 provides a transfer device provided with a meandering correction mechanism that can precisely control the amount of movement of the end of the roller on which the conveyor belt is stretched to correct the meandering of the conveyor belt with high accuracy. ing. Corrects meandering of the rotating conveyor belt by attaching it to one end of the roller shaft and moving one end of the roller shaft in a direction substantially perpendicular to the roller axis. To do. A swing arm having a bearing portion that rotatably supports one end of the roller shaft, a cam surface of the three-dimensional cam, and a contact portion that can come in contact with and away from the guide surface, and a contact of the swing arm by urging the three-dimensional cam A transfer device is provided that includes a cam urging member that presses a guide surface against a contact portion, and a pressing unit that presses a contact portion of a swing arm against the cam surface.
However, when the meandering correction mechanism is attached, the problem of the increase in size and the cost cannot be solved because the main body size increases and the number of parts increases.

Therefore, the present invention has been made in view of the above problems, and its problem is to greatly reduce toner scattering from the end of the photosensitive member cleaning member to prevent contamination in the image forming apparatus and to meander the belt. An object of the present invention is to provide an image forming apparatus that suppresses breakage of the belt end portion due to riding.
Another object of the present invention is to provide an image forming apparatus that is reduced in size and cost by reducing the number of parts in order to provide a function of suppressing breakage of the belt end.

The features of the present invention, which is a means for solving the above problems, are listed below.
The image forming apparatus of the present invention comprises an image carrier that carries a latent image, an exposure device that forms a latent image on the image carrier, and the latent image formed on the image carrier is developed with toner, and is visible. A developing device that forms an image, a transfer device that transfers a visible toner image of the image carrier to a recording member, and a cleaning device that includes an image carrier cleaning member that cleans residual toner on the image carrier. In the image forming apparatus, the transfer device includes a belt stretched by at least two rollers for transporting the recording member, and a belt for cleaning untransferred toner on the belt on the non-transport surface side of the recording medium. At least one of the cleaning member, the roller, an abutting member that abuts the end surface of the belt against an axial end, and a position near the contact position of the abutting member and the belt, A pressing member that suppresses the undulation generated in the belt by pressing from the belt surface in the thickness direction of the belt, and the belt cleaning member is disposed between the separation point of the belt and the recording member and the pressing member. The inner end portion of the pressing member is disposed inside the end portion of the belt cleaning member, and the width of the belt cleaning member is wider than the width of the image carrier cleaning member. Features.
The image forming apparatus of the present invention is further characterized in that the pressing member is disposed on the non-conveying surface side of the recording member of the belt. The image forming apparatus of the present invention further includes the pressing member. The member is a sliding member that can contact the belt.

The image forming apparatus of the present invention is further characterized in that a felt is used at least on the contact surface with the belt of the sliding member. Further, the image forming apparatus of the present invention further includes the pressing member. Is a rotating member that interlocks with the movement of the belt while being in contact with the belt. Further, in the image forming apparatus of the present invention, the rotating member further includes a sponge on a contact surface with the belt. The image forming apparatus of the present invention is further characterized in that the pressing member is supported by a stationary member provided separately from the roller and the belt. The image forming apparatus of the present invention is further characterized in that the pressing member is detachably attached to the belt. Location further the pressing member, characterized in that the are in the thickness direction of the belt is urged toward the surface of the belt

The present invention, which is a means for solving the above problems, has the following specific effects.
The image forming apparatus of the present invention can greatly reduce the scattering contamination due to the toner leaking from the end of the cleaning member with respect to the photoreceptor.
In addition, the image forming apparatus of the present invention can prevent the belt from climbing up due to the arrangement of the belt pressing member, and can prevent damage due to the deviation of the conveying belt.
Furthermore, the image forming apparatus of the present invention can be reduced in size and cost by disposing the belt pressing member inside the end portion of the belt cleaning member.

1 is a diagram illustrating a configuration of an image forming apparatus of the present invention. 2A and 2B are diagrams illustrating a configuration of a tension roller and a conveyance belt in the image forming apparatus of the present invention, in which FIG. 1A is a perspective view thereof, and FIG. FIG. 4 is a diagram illustrating a positional relationship between a belt cleaning unit and a pressing member in the image forming apparatus of the present invention. It is a figure which shows the structure of the pressing member in the image forming apparatus of this invention. FIG. 3 is a diagram illustrating a positional relationship among a pressing member, a belt cleaning member, a photosensitive member cleaning member, and a belt cleaning member in the image forming apparatus of the present invention. It is a figure which shows the example of a shape of the pressing member in the direct transfer system of the belt apparatus of this invention. It is a figure which shows the installation structure structure of the pressing member in the direct transfer system of the belt apparatus of this invention. It is a figure which shows the structure of other embodiment of the pressing member in the image forming apparatus of this invention, (a) A holder part is arrange | positioned at a bearing, (b) A holder part is arrange | positioned at a sheet metal, (c) A holder part is arranged. It is the figure arrange | positioned at the flange which is a butting member. It is a figure which shows the attachment or detachment structure of the pressing member in the direct transfer system of the belt apparatus of this invention. It is a figure which shows the structure which provides a pressing force to the pressing member in the direct transfer system of the belt apparatus of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

FIG. 1 is a schematic diagram illustrating a configuration using a conveyance belt as an embodiment of an image forming apparatus according to the present invention. FIG. 1 illustrates a typical tandem image forming apparatus having a conveyor belt as an embodiment.
An image forming apparatus 1 according to an embodiment of the present invention includes, from above, an image forming unit 3 that forms a toner image, and a recording member 9 such as a recording sheet below it, and a paper feeding unit 2 that supplies the recording member 9 Has been. In addition, although not shown, an automatic document feeder (ADF) that automatically conveys a placed document and a scanner (reading device) that reads the document may be provided.
The image forming apparatus 1 has an image forming unit 3 disposed at the center thereof. In the image forming unit 3, four image forming units 10 as process cartridges corresponding to yellow (Y), magenta (M), cyan (C), and black (K) toners are provided at approximately the center of the image forming unit 3. They are arranged in a tandem shape arranged in parallel in the horizontal direction.
Above the four image forming units 10Y, 10C, 10M, and 10K, there is an exposure device 12 that exposes the surface of the photoreceptor 11 as a charged image carrier based on the image data of each color to form a latent image. Is provided.
In addition, the four image forming units 10Y, 10C, 10M, and 10K are made of a heat-resistant material such as polyimide or polyamide that is wound around and supported by rollers 641 and 642 to adjust the electric resistance. A transfer device 60 having an endless belt made of the above-described substrate as a conveying belt 61 is disposed.
Each of the image forming units 10Y, 10C, 10M, and 10K includes photoreceptors 11Y, 11C, 11M, and 11K. Around each photoreceptor 11, charging devices 13Y, 13C, and 13M that apply charges to the surface of the photoreceptor 11 are provided. , 13K, developing the latent image formed on the surface of the photoconductor 11 with each color toner to form a toner image 20Y, 20C, 20M, 20K, lubricant application for applying a lubricant (not shown) to the surface of the photoconductor 11 Cleaning devices 30Y, 30C, 30M, and 30K including photosensitive member cleaning members 31Y, 31C, 31M, and 31K, which are cleaning blades for cleaning the surface of the photosensitive member 11 after the transfer of the toner image, are disposed. Thus, each of them forms one image forming unit 10Y, 10C, 10M, 10K.
These can be used as a process cartridge for the image forming apparatus 1 by being detachable.
Since any image forming unit 10 has the same configuration, in this figure, the display of Y, C, M, and K is omitted if it is not related to the distinction of colors.

The photoconductor 11 is a metal such as amorofus silicone or selenium, or an organic photoconductor. Here, the photoconductor 11 is described as an organic photoconductor. The organic photoreceptor 11 has a cylindrical drum shape, and rotates at a predetermined linear velocity, here, a linear velocity of 50 mm / s. On the conductive support, a photosensitive layer having a filler-dispersed resin layer, a charge generation layer and a charge transport layer, and a protective layer having a filler dispersed on the surface thereof are provided.
The photosensitive layer may be a single-layered photosensitive layer containing a charge generation material and a charge transport material, but a laminated type composed of a charge generation layer and a charge transport layer is excellent in sensitivity and durability.
In the charge generation layer, a pigment having charge generation ability is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, an attritor, a sand mill, an ultrasonic wave, etc., and this is coated on a conductive support. It is formed by drying. As binder resin, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinylcarbazole, polyacrylamide, polyvinyl benzal, polyester Phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone and the like. The amount of the binder resin is suitably 0 to 500 parts by mass, preferably 10 to 300 parts by mass with respect to 100 parts by mass of the charge generating material.
The charge transport layer can be formed by dissolving or dispersing the charge transport material and the binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer. Charge transport materials include hole transport materials and electron transport materials. As the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Polyvinylidene chloride, polyarate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol Examples thereof include thermoplastic or thermosetting resins such as resins and alkyd resins.
In addition, a protective layer may be provided on the photosensitive layer. By providing the protective layer and improving the durability, the photosensitive member 11 having high sensitivity and no abnormal defects of the present invention can be used effectively.
Materials used for the protective layer include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, Examples thereof include resins such as polybutylene terephthalate, polycarbonate, polyarylate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyvinylidene chloride, and epoxy resin. Of these, polycarbonate or polyarylate can be most preferably used. Other protective layers include fluorine resins such as polytetrafluoroethylene, silicone resins, and inorganic fillers such as titanium oxide, tin oxide, potassium titanate, and silica for the purpose of improving wear resistance. What disperse | distributed the filler etc. can be added. The filler concentration in the protective layer varies depending on the type of filler used and also on the electrophotographic process conditions using the photoreceptor 11, but is preferably 5% by mass or more in the ratio of filler to the total solid content on the outermost layer side of the protective layer. 10 mass% or more and 50 mass% or less, Preferably about 30 mass% or less is favorable.

Image information is exposed by the exposure device 12 serving as a latent image forming unit, and an electrostatic latent image is formed. This latent image is formed by a laser beam scanner or LED using a laser diode (LD).
The charging device 13 includes a charging roller configured by covering a conductive cored bar with a medium-resistance elastic layer as a charging member. The charging roller is connected to a power source (not shown), and is applied with a predetermined direct voltage (DC) and / or alternating voltage (AC). The charging roller for discharging the ions uses an elastic resin roller as a material. Further, the charging roller may contain an inorganic conductive material such as carbon black and an ionic conductive material in order to adjust electric resistance.
Further, the charging roller is disposed with a small gap with respect to the photoreceptor 11. The minute gap is set by, for example, winding a spacer member having a certain thickness around the non-image forming regions at both ends of the charging roller so that the surface of the spacer member abuts on the surface of the photoreceptor 11. be able to. Further, the charging roller may be brought into contact without being brought close to the photosensitive member. The photosensitive member 11 can be charged by discharging at a portion that is in a roller shape and is close to the photosensitive member 11. Further, by making them close and not in contact with each other, it is possible to suppress the occurrence of contamination due to the transfer residual toner of the charging roller. In addition, the charging roller may be provided with a charging cleaner roller (not shown) that performs cleaning by contacting the surface of the charging roller.
The developing device 20 uses a one-component developer. In the one-component developer, either magnetic toner or non-magnetic toner may be used. In the developing device 20 of the present invention, the developer is smoothly conveyed so as not to give stress and stay in the developing device 20 without using a stirring / mixing medium called a carrier. The toner replenished in the developing device 20 is conveyed by a developer supply roller, carried on the developing sleeve, and conveyed to a region facing the photoconductor 11. Here, the developing sleeve moves in the same direction at a linear velocity faster than the surface of the photoconductor 11 in a region facing the photoconductor 11. The toner on the developing sleeve supplies the toner to the surface of the photoconductor 11 while rubbing the surface of the photoconductor 11. At this time, a developing bias is applied to the developing sleeve from a power source (not shown), whereby a developing electric field is formed in the developing region. Then, between the electrostatic latent image on the photoreceptor 1 and the developing sleeve, an electrostatic force acting on the toner on the developing sleeve toward the electrostatic latent image works, and the toner is applied to the electrostatic latent image on the photoreceptor 11. Will adhere. At this time, the toner images of the corresponding colors are developed.
Further, in the developing device 20 using the two-component developer including the carrier, a developing sleeve provided with a magnetic field generating unit (not shown) is disposed at a position facing the photoreceptor 11. Below the developing sleeve, a stirring / conveying screw having a mechanism for mixing toner introduced from a toner bottle (not shown) with a developer and pumping the toner into the developing sleeve while stirring is provided. The two-component developer composed of the toner and the magnetic carrier conveyed by the developing sleeve is regulated to a predetermined developer layer thickness by the regulating member and is carried on the developing sleeve. The developing sleeve carries and conveys the developer while moving in the same direction at the position facing the photoreceptor 11, and causes the toner to act on the photoreceptor 11 to adhere to the electrostatic latent image on the photoreceptor 11. Become.

The cleaning device 30 for the photoconductor 11 includes a photoconductor cleaning member 31 that is a cleaning blade for cleaning residual toner on the photoconductor 11, a holder (not shown) that holds the blade, and the like. Residual toner is removed from the photoreceptor 11 by pressing the body cleaning member 31. The photoconductor cleaning member 31 is provided with a mechanism for contacting / separating from the photoconductor 11 and can be arbitrarily contacted / separated by the control unit of the image forming apparatus 1. The photosensitive member cleaning member 31 is brought into contact with the photosensitive member 11 in a counter manner, whereby an additive such as toner remaining on the photosensitive member 11, talc of the recording member 9 adhering as dirt, kaolin, calcium carbonate or the like is added. Remove from the photoreceptor 11 and clean. The removed toner or the like is conveyed and stored in a waste toner container (not shown) by a waste toner collection coil (not shown).
The toner cleaned by the cleaning device 30 and removed from the photoconductor 11 is collected by a serviceman or the like by a toner conveying member, or is carried as a recycled toner to a developing device or the like and used for development.

2A and 2B are diagrams illustrating the configuration of the tension roller and the conveyance belt in the image forming apparatus of the present invention, in which FIG. 2A is a perspective view thereof and FIG. 2B is a sectional view from the front.
The transfer device 60 conveys the toner image on the photoconductor 11 and the conveyance belt 61 that conveys the recording member 9 to the fixing device 70 via the image forming units 10Y, 10C, 10M, and 10K arranged in a tandem type. A transfer roller for transferring and laminating the recording member 9 on the belt 61 is provided.
The transfer roller 62 transfers the toner image formed on the photoconductor 11 to the recording member 9 on the conveyance belt 61 at a position facing each photoconductor 11 with the conveyance belt 61 interposed therebetween. 62M and 62K are respectively arranged. The transfer roller 62 is connected to a power source (not shown), and is applied with a predetermined direct current voltage (DC) and / or alternating current voltage (AC). The polarity of the voltage to be applied is opposite to the polarity of the charge of the toner, and transfer is performed by attracting and transferring from the photoreceptor 11 to the conveying belt 61 side. Here, by applying a predetermined transfer bias +400 to +2500 V supplied from a single high-voltage power source, a transfer electric field is formed, and a toner image on the photoconductor 11 is sequentially transferred to the recording member 9 to form a full-color image. It is formed.
As will be described in detail later, the conveyor belt 61 is stretched by a tension roller 641 and a drive roller 642, and is rotationally driven by a drive motor (not shown) via the drive roller 642. The belt tension is applied by springs on both sides of the tension roller 641. The tension roller 641 has an aluminum pipe shape with a diameter of Φ19 mm and an axial width of 231 mm. At both ends, as shown in (b), flanges 66 having a diameter of Φ22 mm are press-fitted to serve as abutting members 66 that regulate meandering of the conveyor belt 61.

As the driving roller 642, polyurethane rubber (thickness: 0.3 to 1 mm), thin layer coating roller (thickness: 0.03 to 0.1 mm), or the like can be used. A small urethane coating roller (thickness 0.05 mm, diameter Φ19) was used.
As the transfer roller 62, a conductive sponge roller or a conductive solid roller can be used.
In the case of a conductive sponge roller, an elastic body adjusted to a resistance value of 10 ⁴ to 10 ¹³ Ω with a conductive material is coated on a metal core such as SUS. As the material, an ion conductive roller (carbon dispersion in urethane, NBR, hydrin), an electronic conductive type roller (EPDM) or the like is used, and the toner image on the photoreceptor 11 has an Asker C hardness of 35 ° to 60 °. Is transferred to the conveyor belt 61.
Thus, the transfer roller 62 is preferably semiconductive by containing an inorganic conductive material such as carbon black and an ionic conductive material in order to adjust the electric resistance. Even if the resistance value of the transfer roller 62 is different, the transfer efficiency is hardly changed. However, if the image area ratio is different, the transfer efficiency is greatly different, so that the transfer efficiency cannot be stably maintained. This is because the current flows preferentially to the portion where the toner is not present in the transfer nip portion. As a result, when the image area ratio is small, the transfer voltage value becomes low and the electric field necessary for transfer cannot be obtained sufficiently. is there. In particular, when the resistance value of the transfer roller 62 is low, the influence of the resistance value of the toner interposed in the transfer portion becomes large.

  Further, the image forming apparatus 1 is provided with a lubricant application device that applies a lubricant to the transport belt 61. The lubricant application device 67 is a solid lubricant contained in a fixed case, a brush roller that contacts the solid lubricant, scrapes the lubricant, and is applied to the conveyor belt 61 and a lubricant applied by the brush roller. A leveling lubricant application blade is provided. The solid lubricant is formed in a rectangular parallelepiped shape and is urged toward the brush roller by a pressure spring. The solid lubricant is scraped off and consumed by the brush roller, and the thickness of the solid lubricant decreases with time. However, since the solid lubricant is pressurized by the pressure spring, the solid lubricant is always in contact with the brush roller. The brush roller applies the lubricant scraped off while rotating to the surface of the conveyor belt 61. Note that a lubricant application device having a similar function may be provided for the photoreceptor 11. In this embodiment, a lubricant application blade (not shown) as a lubricant leveling means is brought into contact with the surface of the conveying belt 61 on the downstream side in the moving direction with respect to the lubricant application position by the brush roller. The lubricant application blade is made of rubber which is an elastic body, has a function as a cleaning means, and is in contact with the moving direction of the transport belt 61 in the counter direction. As the solid lubricant, a dry solid hydrophobic lubricant can be used. In addition to zinc stearate, metal compounds having fatty acid groups such as stearic acid, oleic acid, and palmitic acid can also be used. . Further, waxes such as candelilla wax, carnauba wax, rice wax, wax, ooba oil, beeswax, and lanolin can be used.

A toner mark sensor 65 is provided for the transport belt 61. A toner mark sensor 65 is located in the middle of the image forming apparatus 1 slightly in the lower right. The toner mark sensor 65 measures the toner image density and each color position on the conveyance belt 61 by using a regular reflection type or diffusion type sensor, and adjusts the image density and color matching.
On the left side of the toner mark sensor 65, a transport belt cleaning device 63 (not shown) including a belt cleaning member 631 for cleaning the surface of the transport belt 61 after transfer is provided. Further, the belt cleaning member 631 includes a mechanism in which the roller 64 contacts and separates from the conveyance belt 61, and can be arbitrarily contacted and separated by the control unit of the main body of the image forming apparatus 1.
The belt cleaning member 631 performs cleaning by scraping off the toner on the conveyance belt 61. As a material of the belt cleaning member 631, urethane rubber having a thickness of 1.5 to 3 mm and a rubber hardness of 65 to 80 ° is used, and is in contact with the conveyance belt 61 by a counter. The transfer residual toner thus scraped off is stored in a transfer toner waste toner storage section (not shown) through a toner transport path (not shown). At least one of the portion corresponding to the cleaning nip portion of the conveyance belt 61 or the edge portion of the belt cleaning member 631 is coated with a coating agent such as a lubricant, toner, zinc stearate, etc. at the time of assembly. In addition to preventing curling up, a dam layer is formed in the cleaning nip to improve cleaning performance.
Each roller that stretches the conveyor belt 61 is supported from both sides of the conveyor belt 61 by a conveyor belt unit side plate (not shown).

Materials used for the conveyor belt 61 include PVDF (vinylidene fluoride), ETFE (ethylene-tetrafluoroethylene copolymer), PI (polyimide), PC (polycarbonate), TPE (thermoplastic elastomer), carbon black, etc. A resin film-like endless belt is used by dispersing the conductive material. In the present embodiment, a belt having a thickness of 90 to 160 μm and a width of 230 mm is used in a single-layer structure in which carbon black is added to TPF having a tensile modulus of 1000 to 2000 MPa.
The resistance of the conveyor belt 61 is 10 ⁹ to 10 ¹³ Ω · cm in volume resistivity and 10 ¹⁰ to 10 ¹⁴ Ω / □ in the environment of 23 ° C. and 50% RH (both made by Mitsubishi Chemical Corporation HirestaUpMCP- It is desirable to be within the range of measurement with HT450, applied voltage of 500 V, and applied time of 10 seconds. When the volume resistivity and the surface resistivity of the transport belt 61 exceed the above-described ranges, the transport belt 61 is charged. Therefore, it is necessary to take a measure such as setting the set voltage value higher as it goes downstream in the image forming order. This makes it difficult to use a single power supply for the transfer section. This is because the discharge potential generated in the transfer process, the recording member peeling process, etc. increases the charged potential on the surface of the conveyor belt 61 and makes it difficult to perform self-discharge. Arise. Further, if the volume resistivity and surface resistivity are below the above ranges, the charge potential decays faster, which is advantageous for static elimination by self-discharge. However, since the current during transfer flows in the surface direction, it is sufficient for the toner layer. A transfer electric field is not applied, and toner scattering occurs. Therefore, the volume resistivity and the surface resistivity of the transport belt 61 in the present invention are within the above ranges.

  The recording member 9 is held on the paper feed tray 80 or the manual feed tray 87 and is conveyed to the registration roller pair 84 by the paper feed roller 82 or the manual paper feed roller 82, and the front end of the toner image on the photoconductor 11 is transferred. The paper is fed in accordance with the timing of reaching the copy. Thereafter, a fixing device 70 for fixing the toner image on the recording member 9 to the recording member 9 semi-permanently is provided next to the transfer device 60. Although not shown, the fixing device 70 is mainly composed of a fixing roller 71 having a halogen heater inside, and a pressure roller 72 disposed so as to be opposed to and pressed against the fixing roller 71. The fixing device 70 is controlled by a control unit (not shown) so as to control fixing conditions based on full-color and monochrome images, single-sided or double-sided, and optimal fixing conditions according to the type of recording member. After the image is transferred and fixed on the recording member 9, it is finally discharged onto the discharge tray 86 by the discharge roller 85.

FIG. 3 is a diagram showing the configuration of the transfer device in the image forming apparatus of the present invention.
As shown in FIG. 3, a cleaning member 621 for cleaning a toner image, a plurality of photoconductors 11Y, 11C, 11M, and 11K, and toner images held on the photoconductors 11Y, 11C, 11M, and 11K are recorded on the recording member. 9 includes a transfer device 60 for superimposing and transferring the image on the upper side.
The transfer device 60 cleans the toner image on the conveyance belt 61 on the conveyance belt 61 stretched by a tension roller 641 and a driving roller 642 for conveying the recording member 9 and the non-conveyance surface side of the recording member 9. The cleaning member 621 is provided.
In this case, the non-conveying surface side indicates a part of the conveying belt where the recording member 9 is not conveyed, and in FIG. A portion from the driving roller 642 to the tension roller 641 is shown.
The width of the cleaning member 621 of the conveyance belt 61 is made wider than the width of the cleaning member (not shown) of the photoconductor 11.
Further, at least one of the rollers 64 has a flange 66 as an abutting member (not shown) capable of abutting the end surface of the conveying belt 61 on the end in the axial direction.
The flange 66 is provided at the edge of the roller 64 over which the conveyor belt 61 is stretched or at the end of the roller 64, and serves as an abutting guide, thereby serving as an abutting member that regulates meandering of the conveyor belt 61.

Further, in the vicinity of the position where the flange 66 and the conveyor belt 61 are in contact with each other, a pressing member 67 that presses from the surface of the conveyor belt 61 and suppresses the undulation generated in the conveyor belt 61 is provided.
FIG. 4 is a diagram showing a configuration of an embodiment of a pressing member in the image forming apparatus of the present invention.
As shown in FIG. 4, a pressing member 67 is provided in the vicinity of a position where the flange 66 provided on the tension roller 641 and the conveying belt 61 are in contact with each other.
The pressing member 67 is pressed from the surface side of the conveyor belt 61 toward the center of the tension roller 641 in the thickness direction of the conveyor belt 61, and suppresses the undulation generated in the conveyor belt 61. The pressing member 67 is disposed so that the vicinity of the end surface of the conveyance belt 61 that contacts the flange 66 corresponding to the abutting member is pressed.
For this purpose, the pressing member 67 is provided so as to be held by the holder member 68 and press the conveying belt 61 via the holder member 68.
The pressing member 67 uses a sliding member 671 that can slide so as not to become a resistance to the movement of the conveying belt 61 when the surface of the conveying belt 61 is pressed. As a material of the sliding member 671, a sliding material such as sliding polyacetal (POM), sliding acrylonitrile-butadiene-styrene (ABS), a natural fiber, a synthetic resin fiber, or the like is used.
In the image forming apparatus 1 of the present invention, the belt cleaning member 631 is disposed between the separation point 601 of the conveyance belt 61 and the recording member 9 and the pressing member 67. In FIG. 4, the direction of rotation is indicated by an arrow.
This is because, when the recording member 9 conveyed by the conveying belt 61 is separated, the photosensitive member 11 is wider in the axial direction than the recording member 9, and therefore, the portion other than the recording member 9 portion on the conveying belt 61. In some cases, the transfer toner remains on the surface. The recording member 9 such as transfer paper contains additives such as calcium carbonate, talc, and kaolin. These additives may be separated from the recording member 9 by the transfer bias by the transfer roller 62 or the like and transferred to the conveying belt 61. Some of these have a high hardness, and the conveying belt 61 may be polished by contacting and sliding on the pressing member 67 as it is. Therefore, by disposing the belt cleaning member 631 between the separation point 601 and the contact / sliding portion of the pressing member 67, it is possible to prevent the conveyance belt 61 from being worn and the toner from being scattered.

Further, in the image forming apparatus 1 of the present invention, the inner end portion of the pressing member 67 is disposed inside the end portion of the belt cleaning member 631.
FIG. 5 is a diagram showing the positional relationship between the pressing member, the belt cleaning member, the photosensitive member cleaning member, and the belt cleaning member in the image forming apparatus of the present invention.
As shown in FIG. 5, the transport belt 61 is stretched between a tension roller 641 and a drive roller 642. Further, the belt cleaning member 631 and the pressing member 67 are in contact with the conveyance belt 61. At this time, the inner end of the pressing member 67 is arranged inward of the inner side of the end of the belt cleaning member 631 in contact with the conveying belt 61 toward the inner side of the image forming apparatus 1. As a result, by disposing the inner end of the pressing member 67 in the region where the belt cleaning member 631 has cleaned dirt such as untransferred toner on the conveyance belt 61, it is possible to prevent the conveyance belt 61 from being worn.
As shown in FIG. 5, in the image forming apparatus 1 of the present invention, the width of the belt cleaning member 631 is wider than the width of the photoconductor cleaning member 31.
Accordingly, the cleaning member 631 of the conveyance belt 61 is disposed between the separation point of the conveyance belt 61 and the recording member 9 and the pressing member 67, and the inner end portion of the pressing member 67 is the cleaning member of the conveyance belt 61 in the thrust direction. It is arranged inside the end portion of 631. Since the width of the cleaning member 631 of the conveyance belt 61 is wider than the width of the cleaning member 31 of the photosensitive member 11, the toner leaking from the end of the cleaning member 31 of the photosensitive member 11 is cleaned by the cleaning member 631 of the conveyance belt 61. Is done. Therefore, it is possible to reduce the amount of toner that enters the holding member 67 and scatters.

FIG. 6 is a view showing the configuration of another embodiment of the pressing member in the image forming apparatus of the present invention. As shown in FIG. 6, the pressing member 67 is configured by a rotating member 672 that can be rotated by being driven while pressing the conveyance belt 61. The pressing member 67 can be rotated by inserting a rotation shaft 681 rotatably supported by the holder member 68, and rotates following the movement of the conveyance belt 61.
The rotating member 672 used as the pressing member 67 is made of a sliding polyacetal (POM), a sliding acrylonitrile-butadiene-styrene (ABS), which is a highly slidable material that does not hinder the movement of the conveyor belt 61, Although a synthetic resin sliding sponge or the like is used, a sponge material is used for the contact surface between the conveying belt 61 and the pressing member 67 of the present invention.

FIG. 7 is a view showing a configuration of another embodiment of the pressing member in the image forming apparatus of the present invention. As shown in FIG. 7, the pressing member 67 is supported by an immovable member 69 that is provided separately from the tension roller 641 and the conveyance belt 61.
Here, the immovable member 69 is constituted by a side plate of the main body of the transfer device 60 including the conveyance belt 61. Further, the immovable member 69 may be a bearing of a roller 64 provided in the transfer device 60 or a main body frame of the image forming apparatus 1.
When the tension roller 641 and the flange 66 of the tension roller 641 are not driven, the immovable member 69 may be the flange 66. In this immovable member 69, the pressing member 67 described above is installed in an integral structure with holder members 68 attached to both sides or one side of the conveyance belt 61 in the width direction.

FIG. 8 is a diagram showing the configuration of another embodiment of the pressing member in the image forming apparatus of the present invention, in which (a) the holder portion is disposed on the bearing, (b) the holder portion is disposed on the sheet metal, ) It is the figure which has arrange | positioned the holder part to the flange which is a butting member.
As another embodiment, as shown in (a), the pressing member 67 presses the conveyor belt 61 by a holder member 68 fixed to a bearing 643 located outside the flange 66. . The pressing member 67 can be fixed to the conveyor belt 61 by disposing the pressing member 67 beyond the flange 66. As a result, the pressing member 67 can suppress buckling at the flange 66 which is a shift regulating portion at the end of the conveyor belt 61. The belt device and product life can be extended with an inexpensive and compact configuration.
Further, as shown in (b), a holder member 68 for pressing the pressing member 67 against the conveying belt 61 is disposed on the sheet metal 644. The sheet metal 644 is not driven, and the buckling at the flange 66 at the end of the conveyor belt 61 can be suppressed by installing the pressing member 67 at this location.
Further, as shown in (c), the flange 66 is configured so as not to be driven by the tension roller 641, and the pressing member 67 is formed on the conveying belt 61 by a holder member 68 fixed on the flange 66. At the end. The holder member 68 is fixed with a snap hook, a screw, an adhesive, or the like. At least one pressing member 67 is disposed at a portion in contact with the flange 66 and the conveyor belt 61. By installing the pressing member 67 at the place of the flange 66, buckling due to the deviation of the conveyor belt 61 can be suppressed by the flange 66.
As a result, it is possible to prevent the toner from accumulating on the pressing member 67 and then scattering of the toner, so that the inside of the transfer device 60 and the inside of the image forming apparatus 1 can be prevented from being contaminated and causing a power failure or a process error. In addition, end buckling of the conveyor belt 61 can be suppressed with a minimum configuration, and stable belt driving can be performed over a long period of time.

  FIG. 9 is a diagram showing a configuration of another embodiment of the pressing member in the image forming apparatus of the present invention. As shown in FIG. 9, if the fixing member 69 is attached to and detached from the immovable member 69, the pressing member 67 can be provided so as to be able to contact and separate from the conveyance belt 61, and replacement is necessary due to wear of the pressing member 67. It is also possible to make it convenient. As a result, only the part to be exchanged can be removed, so that an increase in cost can be prevented by minimizing the addition of a new part.

  FIG. 10 is a diagram showing a configuration of another embodiment of the pressing member in the image forming apparatus of the present invention. As shown in FIG. 10, an elastic body 682 such as a spring disposed between the holder member 68 integrated with the immovable member 69 and the pressing member 67 is disposed. In this configuration, the pressing member 67 can be displaced in the thickness direction of the transport belt 61. In addition, since the shape restoring force of the elastic body 303 can be used, the holding member 67 is always attached to the conveying belt regardless of the change in the gap between the surface of the conveying belt 61 and the holding member 67 due to the eccentricity of the tension roller 641 or the like. Since it can be pressed against the surface of 61, buckling deformation that is to occur in the conveyor belt 61 can be suppressed.

Next, the image forming operation of the present invention will be described.
The charging device 13 is in pressure contact with the surface of the photoreceptor 11 and is driven to rotate by the rotation of the photoreceptor 11. A predetermined bias is applied to the charging device 13 by a high voltage power source (not shown), and the surface of the photoconductor 11 is uniformly charged to a predetermined potential. Thereafter, the photoreceptor 11 forms an electrostatic latent image pattern on its surface in response to the exposure given by the exposure device 12. The developing device 20 is provided with a developing roller in pressure contact with the surface of the photoconductor 11, and a predetermined developing bias is applied from a high voltage power source (not shown). The toner supplied onto the developing roller adheres to the electrostatic latent image pattern on the photoconductor 11 under a developing bias potential and forms a toner image.
A primary transfer bias is applied to the transfer roller 62 by a high voltage power source (not shown), and the toner image on the photoreceptor 11 is transferred onto the surface of the conveyance belt 61. The conveyor belt 61 is driven to rotate in the direction of the arrow in the drive roller 642.
At this time, the flange 66 provided at the end of the tension roller 641 regulates the shift of the conveyor belt 61 to prevent the belt from being damaged. Furthermore, the pressing member 67 provided on the holder member 68 can be pressed against the conveyor belt 51 to suppress the end buckling of the conveyor belt 61, and the belt can be driven stably over a long period of time. It becomes possible.
The toner image formed on the surface of the conveyance belt 61 is transferred to the recording member 9 by applying a voltage to the transfer roller 62, fixed by the fixing device 70, and output. The cleaning member 31 of the cleaning device 30 cleans the transfer residual toner on the surface of the photoconductor 11.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Paper feed part 3 Image forming part 4 Scanner part 401 Contact glass 5 Automatic document feeder (ADF)
9 Recording member 10 Image forming unit (process cartridge)
DESCRIPTION OF SYMBOLS 11 Photoconductor 12 Exposure apparatus 13 Charging apparatus 20 Developing apparatus 30 Cleaning apparatus 60 Transfer apparatus 601 Separation point 61 Conveying belt 62 Transfer roller 63 Belt cleaning apparatus 631 Belt cleaning blade 64 Roller 641 Tension roller 642 Drive roller 643 Bearing 644 Sheet metal 65 Toner mark Sensor 66 Flange 67 Holding member 671 Sliding part 672 Rotating part 68 Holder member 681 Rotating shaft 682 Elastic body 69 Non-moving member

Japanese Patent Laying-Open No. 2005-092029 JP 2009-184767 A

Claims (9)

An image carrier for carrying a latent image;
An exposure apparatus for forming a latent image on the image carrier;
A developing device that develops the latent image formed on the image carrier with toner and visualizes the latent image;
A transfer device for transferring the visible toner image of the image carrier to a recording member;
An image forming apparatus comprising: a cleaning device having an image carrier cleaning member that cleans transfer residual toner on the image carrier;
The image forming apparatus includes:
A belt stretched by at least two rollers for conveying the recording member;
A belt cleaning member for cleaning untransferred toner on the belt on the non-conveying surface side of the recording medium;
At least one of the rollers includes an abutting member that abuts the end surface of the belt against an axial end portion;
In the vicinity of the contact position between the abutting member and the belt, there is a pressing member that presses from the belt surface in the thickness direction of the belt and suppresses the undulation generated in the belt,
The belt cleaning member is disposed between the separation point of the belt and the recording member and the pressing member;
The inner end of the pressing member is disposed on the inner side of the end of the belt cleaning member, and
The width of the belt cleaning member is wider than the width of the image carrier cleaning member. The image forming apparatus according to claim 1.
The image forming apparatus, wherein the pressing member is disposed on a non-conveying surface side of the recording member of the belt. The image forming apparatus according to claim 1, wherein
The image forming apparatus, wherein the pressing member is a sliding member that can contact the belt. The image forming apparatus according to claim 3.
An image forming apparatus, wherein the sliding member uses a felt at least on a contact surface with the belt. The image forming apparatus according to claim 1, wherein
The image forming apparatus, wherein the pressing member is a rotating member that is in contact with the belt and interlocks with the movement of the belt. The image forming apparatus according to claim 5.
An image forming apparatus, wherein the rotating member uses a sponge material at least on a contact surface with the belt. The image forming apparatus according to claim 4 or 6,
The image forming apparatus, wherein the pressing member is supported by a stationary member provided separately from the roller and the belt. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the pressing member is detachably attached to the belt. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the pressing member is urged toward the surface of the belt in the thickness direction of the belt.

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