JP2007240620A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an economical image forming apparatus which is constituted so that the consumption of a cleaning web can be restrained to the absolute minimum and downtime due to exchange thereof can be restrained to the utmost by making a take-up amount large under an external condition that there are large quantity of deposits such as toner. <P>SOLUTION: The image forming apparatus includes: a first image carrier; a primary transfer part for transferring a toner image formed on the image carrier to a second image carrier by the application of bias having a reverse polarity to the electrification polarity of toner; a secondary transfer means for transferring the toner image transferred to the second image carrier to recording paper; and the cleaning web functioning as a second cleaning means for removing the toner left after secondary transfer remaining on the second image carrier while coming into contact with the surface of the second image carrier at the downstream position of the secondary transfer means. It has a means for detecting the take-up amount of the cleaning web so as to control the revolving speed of a motor for driving a take-up shaft on the basis of a detection signal therefrom. The take-up amount is varied according to an environment table by detecting absolute moisture content which influences transfer efficiency. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that forms a visible image on an image carrier and electrostatically transfers the toner image onto a recording material. For example, the present invention relates to an electrophotographic system or an electrostatic recording system. It can be suitably applied to an image forming apparatus.

  In recent years, in an image forming apparatus using an electrostatic process, an intermediate transfer belt has been widely used because of the need for high-quality images on a wide variety of papers. As the intermediate transfer belt, a resin belt typified by polyimide or the like is generally widely used because of its high image quality, long life, and high stability. Also, as the intermediate transfer belt cleaning device, a blade system as disclosed in Patent Document 1 having a high cleaning capability is widely used in consideration of the surface property of the resin belt and the like.

  On the other hand, recently, the toner has been changed to a smaller particle size and a non-spherical toner shape due to further higher image quality and stabilization of the cleaning ability by the blade method. However, in the intermediate transfer belt made of resin, there is a problem of the hollowing out phenomenon that occurs at the time of transfer accompanying the change in toner. When the image is transferred, a large pressure is applied to the image, so that the toner undergoes stress deformation, the cohesive force between the toners increases, and a part of the image is not transferred onto the image carrier. This is a phenomenon that remains, particularly in characters and line images. In the case of a resin belt, this pressure drop is a problem because the pressure on the image during transfer is large.

  Therefore, in order to eliminate this void, recently, an elastic intermediate transfer belt using at least one elastic layer as a layer structure has become mainstream instead of an intermediate transfer belt using resin. Since the elastic intermediate transfer belt has at least one elastic layer in the layer structure, it is known that the elastic intermediate transfer belt is soft and the pressure acting on the toner in the transfer portion can be reduced, so that it is effective for hollowing out. In addition, since the secondary transfer section has good adhesion to paper, it not only improves transfer efficiency for general paper, but is also effective for transfer to thick paper and transfer to uneven paper. It is known that there is.

  However, when cleaning the elastic intermediate transfer belt, if the blade method is used, the surface layer is elastic, so the contact load of the cleaning blade against the elastic intermediate transfer belt increases, and the edge of the cleaning blade bites into the belt surface layer. This causes problems such as turning over, chattering and squealing of the cleaning blade due to unstable behavior of the edge of the cleaning blade, causing poor cleaning, and increasing frictional force between the belt and the cleaning blade. In addition, various adverse effects such as scratches on the surface layer of the elastic intermediate transfer belt, fusion of toner, and the like may occur, and image quality may be deteriorated. Therefore, in order to avoid the above-described adverse effects, an electrostatic fur brush method, which has a small contact load with the elastic intermediate transfer member, has become common as an elastic intermediate transfer member cleaning method.

  As an electrostatic fur brush method, as in Patent Document 2, a cylindrical member in which conductive fibers are wound around a metal core is brought into contact with a bias applied, and a bias having a polarity opposite to that of toner is applied. Thus, the toner is electrostatically attracted to the fur brush and the toner is removed from the image carrier. It is known that the fur brush method that electrostatically adsorbs toner and removes toner from the belt has more restrictions on the amount of toner that can be cleaned and the toner polarity than the blade method that mechanically removes toner. Yes. Since the electrostatic fur brush method electrostatically adsorbs the toner to the fur brush, the original effect of the fur brush cannot be obtained unless the toner is further transferred from the fur brush with a flicker or a bias application roller. As the amount of toner adsorbed by the fur brush increases, the cleaning performance decreases, and the amount that can be cleaned is generally inferior to the blade method. Further, as described above, since the fur brush method is a method in which toner is adsorbed to the fur brush and cleaned, only toner having a polarity opposite to the bias applied to the fur brush is cleaned. However, the transfer residual toner remaining after the toner image on the intermediate transfer belt is transferred to the paper has the polarity of the toner reversed (from plus to minus or from minus to plus depending on the bias value applied at the time of transfer). ). The transfer residual toner whose polarity is inverted is the same polarity as the applied bias of the fur brush, and therefore is not attracted by the fur brush and passes. The toner that has passed through the fur brush overlaps with the next image, which may cause image defects. For this reason, as disclosed in Patent Document 3, by using two fur brushes and applying biases having different polarities to each other, the bias at the secondary transfer unit, the use environment, the toner deterioration, etc. Thus, the toner can be reliably adsorbed and removed by the fur brush regardless of whether the polarity is positive or negative.

By the way, when the intermediate transfer belt is cleaned by the fur brush used in the electrophotographic system, toner or an external additive of the toner adheres to the surface layer, which causes transfer failure and cleaning failure. As disclosed in Patent Document 4, these can be improved by installing a cleaning web member or the like for removing deposits adhering to the intermediate transfer belt downstream of the cleaning device. However, when a large amount of toner or toner external additive accumulates on the nip portion of the web, the toner or external additive deposited on the image from the nip portion may slip through and cause image defects.
JP 2001-305878 A Patent registration 0236442 JP 2002-207403 A Japanese Patent Laid-Open No. 10-149033

  A cleaning web that cleans deposits such as toner and external additives that cannot be removed by the electrostatic fur brush is always in contact with the downstream side of the electrostatic fur brush, and the cleaning web is excessive. Deposits such as toner are deposited. If a certain amount or more of an adherent such as toner accumulates in the nip between the elastic intermediate transfer belt and the cleaning web, there is a possibility that the image slips through the nip to cause image defects. (There are no particular restrictions on the deposits that adhere to the elastic intermediate transfer member as long as there is a possibility that they may actually adhere.) When trying to maintain a new cleaning web surface at all times, Life is extremely short and uneconomical.

  A first image carrier, a primary transfer portion that transfers a toner image formed on the image carrier to a second image carrier by applying a bias having a polarity opposite to the charging polarity of the toner; Secondary transfer means for transferring the toner image transferred onto the image carrier to the recording paper, and secondary transfer residual toner remaining on the second image carrier at a downstream position of the secondary transfer means, A first cleaning unit having a bias applying unit that contacts and cleans the surface of the second image carrier; and a first cleaning unit that contacts and cleans the surface of the second image carrier at one downstream of the first cleaning unit. Transfer efficiency in an image forming apparatus that has a cleaning web as a second cleaning means, has a means for detecting the winding amount of the cleaning web, and controls the rotation speed of a motor that drives the winding shaft based on the detection signal By detecting the amount of absolute moisture that affects it and changing the winding amount using an environmental table, the amount of cleaning web consumption is minimized by increasing the winding amount under conditions where there is a large amount of toner and other deposits. It is possible to reduce downtime for replacement as much as possible, which is economical.

  A first image carrier, a primary transfer portion that transfers a toner image formed on the image carrier to a second image carrier by applying a bias having a polarity opposite to the charging polarity of the toner; Secondary transfer means for transferring the toner image transferred onto the image carrier to the recording paper, and secondary transfer residual toner remaining on the second image carrier at a downstream position of the secondary transfer means, A cleaning web is provided as a second cleaning means that contacts and cleans the surface of the second image carrier, and has a means for detecting the winding amount of the cleaning web, and the winding shaft is driven based on the detection signal. In an image forming apparatus that controls the number of rotations of the motor, the absolute amount of water that affects transfer efficiency is detected, and the amount of winding is increased under conditions where there is a large amount of deposits such as toner by varying the amount of winding using an environmental table It makes it possible to suppress the consumption of the cleaning web to the minimum necessary, it is possible to suppress the occurrence of down time for the exchange as much as possible, it is economical.

  Hereinafter, the present invention will be specifically described with reference to examples. These examples are examples of the best mode of the present invention, but the present invention is not limited to these examples.

  The first embodiment relates to a tandem type image forming apparatus provided with an image carrier composed of four photosensitive members. As shown in FIG. 1, the image forming apparatus of this embodiment includes a belt-like elastic intermediate transfer member, that is, an endless elastic intermediate transfer belt 181. The elastic intermediate transfer belt 81 is wound around a driving roller 25, a tension roller 26, and a backup roller 29 as a support. Along the horizontal portion of the elastic intermediate transfer belt 81, four image forming portions Pa, Pb, Pc. Pd is arranged in series. The configuration of the image forming unit Pa will be described as an example.

  The image forming unit Pa includes a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 101a which is an image carrier that is rotatably arranged. Around the photosensitive drum 101a, process devices such as a primary charger 122a, a developing device 123a, and a cleaning device 112a are arranged. The other image forming units Pb, Pc, and Pd have the same configuration as the image forming unit Pa, and are respectively photosensitive drums 101b, 101c, and 101d, primary chargers 122b, 122c, and 122d, and developing units 123b, 123c, and 123d. Cleaning devices 112b, 112c, and 112d are provided. These image forming portions Pa, Pb, Pc, and Pd are different in that toner images of respective colors of yellow, magenta, cyan, and black are formed.

  The developing devices 123a to 123d disposed in the image forming units Pa to Pd respectively store yellow toner, magenta toner, cyan toner, and black toner.

  The photosensitive drum 111a is uniformly charged by the primary charger 122a, and an image signal based on the magenta component color of the original is projected from the exposure device 111a onto the photosensitive drum 101a via a polygon mirror or the like to form an electrostatic latent image. . Next, yellow toner is supplied from the developing device 123a, and the electrostatic latent image is developed as a yellow toner image. When the toner image arrives at the primary transfer portion T1 where the photosensitive drum 101a and the elastic intermediate transfer belt 181 come into contact with the rotation of the photosensitive drum 101a, the primary transfer device (first transfer means), that is, the main image is transferred. In the embodiment, the first transfer bias is applied from the transfer roller 124 a, and the yellow toner image is transferred to the intermediate transfer belt 181. When the elastic intermediate transfer belt 181 carrying the yellow toner image is conveyed to the next image forming portion Pb, the image forming portion Pb has been formed on the photosensitive drum 101b by the same method as described above. A magenta toner image is transferred onto the yellow toner image. Similarly, as the elastic intermediate transfer belt 181 advances to the image forming portions Pc and Pd along the arrow direction, after the cyan toner image and the black toner image are superimposed and transferred to the above-described toner image in each transfer portion T1, By this time, the recording material P sent out from the paper feed cassette 160 reaches the secondary transfer portion T2, and the above-mentioned four color toners are transferred by the transfer bias applied to the secondary transfer device (second transfer means) 140. The image is transferred onto the recording material P. The recording material P to which the toner image is transferred is conveyed to the fixing unit 211. The fixing unit 211 fixes the toner image on the recording material P by heat and pressure. The transfer residual toner on the photosensitive member that could not be transferred by the primary transfer member is cleaned by the cleaning device 112, and the transfer residual toner on the intermediate transfer belt 181 that could not be transferred by the secondary transfer member is removed by the first cleaning device 116a. The second cleaning device 116b performs cleaning. The external additive that adheres to the surface of the elastic intermediate transfer belt 118 and cannot be recovered by the cleaning device is scraped off by the cleaning web 125 disposed after the cleaning device and is used for the next image formation.

  Next, the configuration of each unit will be sequentially described by taking the image forming unit Pa as an example. The photosensitive drum 101a as an image carrier is formed by applying an organic photoconductive layer (OPC) to the outer peripheral surface of an aluminum cylinder. The photosensitive drum 101a is rotatably supported at both ends by flanges, and is driven to rotate counterclockwise in the figure by transmitting a driving force from a drive motor (not shown) to one end. .

  The primary charger 122a is a conductive roller formed in a roller shape. The roller is brought into contact with the surface of the photosensitive drum 101a, and a charging bias voltage is applied by a power source (not shown), thereby the surface of the photosensitive drum 101a. Are uniformly charged to a negative polarity.

  The exposure device 111a is composed of an LED array with a polygon mirror (not shown) attached to the tip, and lighting control is performed according to an image signal by a drive circuit (not shown).

  The developing unit 123a is adjacent to the surface of the toner storage unit (not shown) storing toners of black, cyan, magenta, and yellow having negative charging characteristics, and is rotated by a driving unit (not shown) adjacent to the surface of the photosensitive drum 101a. In addition, the image forming apparatus includes a developing roller that performs development by applying a developing bias voltage from a developing bias power source (not shown). In the toner storage portion, toners of yellow, magenta, cyan, and black are stored in the toner storage portion in order from the upstream side in the conveyance direction of the transfer material.

  Inside an intermediate transfer belt 181 to be described later, transfer rollers 124a, 125b, 125c, and 125d are temporary transfer members that are in contact with the intermediate transfer belt 181 so as to face the four photosensitive drums 101a, 101b, 101c, and 101d. Are arranged side by side. These transfer rollers are connected to a transfer bias power source (not shown), and a positive voltage is applied from the transfer roller. Due to this electric field, the intermediate transfer member 181 in contact with the photosensitive drum 101 is applied to the photosensitive drum 101. The upper negative color toner images are sequentially transferred to form a color image.

  In the present invention, the intermediate transfer belt 181 includes an endless elastic intermediate transfer belt as described above. FIG. 2 is a cross-sectional view of an example of the elastic intermediate transfer belt 181. The elastic intermediate transfer belt 181 is an elastic belt having a three-layer structure of a resin layer 181a, an elastic layer 181b, and a surface layer 181c.

  As the resin material constituting the resin layer 181a, polycarbonate, fluororesin (ETFE, PVDF), 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.) Styrenic resins (monopolymer or copolymer containing styrene or styrene-substituted product) such as styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylate ester copolymer, 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 Vinyl-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, silica Use one or more selected from the group consisting of carbon resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins and polyvinyl butyral resins, polyamide resins, polyimide resins, modified polyphenylene oxide resins, modified polycarbonates, etc. can do. However, it is not limited to the said material.

  Further, as the elastic material (elastic material rubber, elastomer) constituting the elastic layer 181b, butyl rubber, fluorine-based rubber, acrylic rubber, EPDM, NBR, acrylonitrile-butadiene-styrene rubber natural rubber, isoprene rubber, styrene-butadiene rubber , Butadiene rubber, Ethylene-propylene rubber, Ethylene-propylene terpolymer, Chloroprene rubber, Chlorosulfonated polyethylene, Chlorinated polyethylene, Urethane rubber, Syndiotactic 1,2-polybutadiene, Epichlorohydrin rubber, Ricone rubber, Fluoro rubber , Polysulfide rubber, polynorbornene rubber, hydrogenated nitrile rubber, thermoplastic elastomer (eg polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyamide, polyurea, polyester Ether-based, it may be used one kind or two kinds or more selected from the group consisting of fluorocarbon resin) or the like. However, it is a matter of course that the material is not limited to the above materials.

  The material of the surface layer 181c is not particularly limited, but a material that increases the secondary transferability by reducing the adhesion force of the toner to the surface of the intermediate transfer belt 181 is required. For example, one kind of resin material such as polyurethane, polyester, epoxy resin, elastic material (elastic material rubber, elastomer), butyl rubber, fluorine rubber, acrylic rubber, EPDM, NBR, acrylonitrile-butadiene-styrene rubber natural rubber, isoprene Using two or more kinds of elastic materials such as rubber, styrene-butadiene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, and urethane rubber to reduce surface energy. Disperse and use materials that are small and improve lubricity, such as fluororesins, fluorine compounds, fluorocarbons, titanium dioxide, silicon carbide powders, one or more particles, or particles with different particle sizes To be able to That.

  A resistance value adjusting conductive agent is added to the resin layer 181a and the elastic layer 181b. The conductive agent for adjusting the resistance value is not particularly limited. For example, carbon black, graphite, metal powder such as aluminum and nickel, tin oxide, titanium oxide, antimony oxide, indium oxide, potassium titanate, antimony oxide-tin oxide Conductive metal oxides such as composite oxide (ATO), indium oxide-tin oxide composite oxide (ITO), and conductive metal oxides are coated with insulating fine particles such as barium sulfate, magnesium silicate, and calcium carbonate. It may be a thing. It is not limited to the conductive agent.

  Examples of the method for manufacturing the intermediate transfer belt 181 include a centrifugal molding method in which a material is poured into a rotating cylindrical mold to form a belt, a spray coating method in which a thin film is formed on the surface, and a cylindrical mold as a material solution. There are a dipping method in which it is soaked in a mold, a casting method in which it is injected into an inner mold and an outer mold, and a method in which a compound is wound around a cylindrical mold and vulcanized and polished. A belt can be manufactured by combining manufacturing methods.

  The color image carried on the intermediate transfer belt 181 in the primary transfer portion is further transferred to the transfer material P by the secondary transfer roller 140 which is in contact with the intermediate transfer belt 181 and is a secondary transfer member. The secondary transfer roller is connected to a power supply for transfer bias (not shown), and a positive voltage is applied from the transfer roller. Due to this electric field, the intermediate transfer belt is applied to the transfer material P in contact with the intermediate transfer 1881 belt. The negative polarity toner image on 181 is sequentially transferred to form a color image.

  Next, the details of the first cleaning unit 116 for residual toner remaining on the intermediate transfer belt 181 after the secondary transfer will be described. As shown in FIG. 3, the electrostatic brush cleaning device includes a device housing 117 disposed in the vicinity of the intermediate transfer belt 181 and a carbon dispersion having a resistance value of 10 MΩ and a fiber thickness of 6 denier provided inside the device housing 2. Is formed by a conductive fur brush 118 formed by flocking a nylon fiber 3 on a metal roller at a density of 500,000 / inch ^ 2 and a metal roller 119 made of aluminum with a hard anodized surface. The first and second intermediate transfer member first cleaning member 161a includes a cleaning blade 120 disposed in contact with the conductive brush roller, and a cleaning member having this configuration is arranged in parallel to the intermediate transfer belt. , 161b constitutes a main part thereof.

  The conductive fur brush 118 is placed in sliding contact with the intermediate transfer belt 181 while maintaining an intrusion amount of about 1.0 mm, and is rotated in the direction of the arrow at a speed of 50 mm / second by a drive motor (not shown). Is formed. The metal roller is arranged so as to maintain an intrusion amount of about 1.0 mm with respect to the conductive fur brush, and is arranged to be rotated in the direction of the arrow at a speed equivalent to that of the conductive fur brush. The cleaning blade 120 that comes into contact with the metal roller is made of urethane rubber, and is disposed so as to maintain an intrusion amount of 1.0 mm with respect to the metal roller.

  A voltage of −700 V (with respect to ground, the same shall apply hereinafter) is applied to a metal roller of the cleaning member 116 a located upstream with respect to the rotation direction of the intermediate transfer belt by a power source (not shown). A voltage of +700 is applied to the metal roller of the cleaning member 116b located on the downstream side with respect to the rotation direction of the intermediate transfer belt. By applying a voltage to the metal roller, a potential difference is generated between the roller and the fur brush, and (+) toner in the transfer residual toner on the intermediate transfer belt 181 is attracted and transferred to the fur brush 118 side. The toner adsorbed and removed is further transferred from the fur brush 118 to the metal roller 119 due to a potential difference, and scraped off by the cleaning blade 120.

  Even if the transfer residual toner on the intermediate transfer belt 181 is cleaned by the cleaning member 116b, the toner having no polarity or the toner having the polarity (−) remains on the intermediate transfer belt 181. These toners are charged (−) by a (−) bias applied to the fur brush. This is considered to be charged by charge injection or discharge.

  The toner can be removed by performing cleaning by applying a (+) bias to the second cleaning member 116b disposed on the downstream side. The removed toner is transferred from the fur brush 118b to the metal roller 119b due to the potential difference, and scraped off by the cleaning blade 120b, whereby the transfer residual toner remaining on the intermediate transfer belt 181 can be removed.

  FIG. 4 shows a detailed view of the cleaning web of the present invention.

  In the second intermediate transfer belt cleaning device 124, a non-woven cleaning web 125 is wound around a web roller 126 from an attachment roller 128 and stretched around a take-up roller 127. The second intermediate transfer belt cleaning device 124 is supported so as to be rotatable about a rotation center 129 and is brought into contact with and separated from the intermediate transfer belt by the pressure release means 130. The cleaning web 125 is brought into contact with the intermediate transfer belt at a position facing the driving roller, and the surface of the intermediate transfer belt is cleaned. The take-up roller 127 is rotationally driven by a driving unit (not shown), and the cleaning web 125 is taken up, whereby new cleaning webs 125 are sequentially supplied to the intermediate transfer belt contact portion.

  In this embodiment, an example in which a nonwoven fabric cleaning web is used as the second intermediate transfer belt cleaning device 124 has been described. However, the scope of application of the present invention is not limited to this, and the intermediate transfer belt is not limited thereto. And is applied to a configuration having a function of collecting deposits on the surface of the intermediate transfer belt inside. For example, a structure in which a roller having a nonwoven fabric wound around the surface is brought into contact with the intermediate transfer belt and driven to rotate may be used.

  The cleaning web 125 disposed after the cleaning device is detachable from the elastic intermediate transfer belt, and is in contact with the surface layer of the elastic intermediate transfer belt 181 with a total pressure of 2.0 kg when worn. As a member of the cleaning web, one type or two or more types selected from polyester, acrylic, vinylon, water-soluble vinylon, rayon, nylon, polypropylene, cotton and the like can be used. However, it is not limited to the said material. The external additive released from the toner is rubbed and adhered to the surface of the elastic intermediate transfer belt at a portion where pressure is applied, such as a transfer portion. Since these cannot be collected by the cleaning device, they are mechanically collected by the cleaning web 125. However, if the same surface of the cleaning web 125 is used for a long time, the cleaning web 125 exceeds the capacity for collecting deposits, and the toner slips from the nip portion between the cleaning web 125 and the elastic intermediate transfer belt 181.

  Therefore, it is necessary to take up a certain amount of the cleaning web 125 after a certain time and renew the contact surface with the elastic intermediate transfer 181 belt.

  The cleaning web winding control method of this embodiment will be described below.

  As shown in FIG. 4, the distance between the nip center between the cleaning means downstream fur brush and the elastic intermediate transfer belt, and the nip center between the cleaning web and the elastic intermediate transfer belt, which are used in this embodiment, is about 50 mm. The distance between the center of the nip where the web and the elastic intermediate transfer belt abut and the center of the nip where the photosensitive drum and the elastic intermediate transfer belt abut is about 97 mm. The process speed of the image forming apparatus of this embodiment is 300 mm / sec.

  The temperature / humidity signal from the environmental sensor is converted into an absolute moisture content by the control device. The transfer environment table is divided into 7 environments based on the absolute water content. In an environment where the transfer efficiency is good and there is little transfer residual toner on the intermediate transfer belt, the winding amount of the cleaning web is wound every 100 sheets of A4 size as shown in FIG. In an environment where there is a large amount of high-temperature, high-humidity transfer residual toner, winding is controlled every 20 A4 size sheets.

  The winding amount is defined by the interval between the teeth of the encoder attached to the shaft end of the web roller that presses the cleaning web against the intermediate transfer belt. In this embodiment, 1 tooth is 2 mm. One tooth of the encoder is controlled by the motor that drives the take-up roller with the control device. For this reason, the amount of winding of the cleaning web is optimized in the usage environment, so that the consumption of the cleaning web can be suppressed to the minimum necessary, which is economical.

  Next, a second embodiment of the present invention will be described. Note that the image forming apparatus of the present embodiment has a configuration substantially similar to that of the first embodiment.

  As shown in FIG. 4, the type of transfer material to be output is selected on the user interface or the computer screen. In this embodiment, the media table is held and the basis weight of the transfer material is 8 divisions from 64g to 300g, the paper type is 16 types, the print mode is single-sided, automatic double-sided, and five modes are controlled. ing.

  For this reason, the amount of the cleaning web wound up in the transfer material used is optimized, so that the consumption of the cleaning web can be suppressed to the minimum necessary, which is economical.

  Next, a second embodiment of the present invention will be described. Note that the image forming apparatus of the present embodiment has a configuration substantially similar to that of the first embodiment.

  The amount of residual toner on the intermediate transfer belt after the secondary transfer increases as the amount of toner consumption increases, and the amount of residual toner further increases in the multiple transfer portion. In the embodiment, the toner consumption amount is analyzed from the output image by the image processing apparatus, and the interval of the cleaning web to be wound is controlled based on the consumption amount of each color.

  For this reason, since the amount of cleaning web to be wound is optimized with respect to the amount of toner consumed, the amount of consumption of the cleaning web can be suppressed to the minimum necessary, which is economical.

1 is a simplified cross-sectional view of an image forming apparatus according to Embodiment 1 of the present invention. 1 is a simplified cross-sectional view showing a cross section of an intermediate transfer belt according to Embodiment 1 of the present invention. FIG. 3 is a simplified cross-sectional view illustrating an intermediate transfer belt cleaning unit according to the first embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified configuration diagram of a cleaning web control mechanism according to Embodiment 1 of the present invention. The cleaning web winding interval in each environmental category.

Explanation of symbols

1a, 1b, 1c, 1d Photosensitive drum (image carrier)
24a, 24b, 24c, 24d Primary transfer portion (first transfer means)
25 Drive roller (support)
26 Tension roller (support)
40 Secondary transfer section (second transfer means)
116a, 116b Intermediate transfer member cleaning device 124 Second cleaning means 125 Cleaning web 126 Web roller 127 Web winding shaft 128 Web attachment shaft 129 Unit rotation center 130 Pressure release means 181 Elastic intermediate transfer belt

Claims (6)

A first image carrier, a primary transfer portion that transfers a toner image formed on the image carrier to a second image carrier by applying a bias having a polarity opposite to the charging polarity of the toner; Secondary transfer means for transferring the toner image transferred onto the image carrier to the recording paper, and secondary transfer residual toner remaining on the second image carrier at the downstream position of the secondary transfer means, A first cleaning unit having a bias applying unit that contacts and cleans the surface of the second image carrier, and a first cleaning unit that contacts and cleans the surface of the second image carrier at a position downstream of the first cleaning unit. In an image forming apparatus having a cleaning web as a second cleaning means and having a control means for controlling the amount of winding of the cleaning web.
An image forming apparatus having a detecting means for detecting temperature, humidity, or both, and varying a winding amount based on the detection result.   The image forming apparatus according to claim 1, wherein the transfer efficiency varies depending on the transfer material, and the amount of winding of the cleaning web can be controlled by selecting the transfer material.   The image forming apparatus according to claim 1, wherein the amount of toner consumption is analyzed by an image processing apparatus, and the winding amount of the cleaning web can be controlled by the toner consumption amount.   The image forming apparatus according to claim 1, wherein the deterioration of the toner is predicted from a number counter, and thereby the amount of winding of the cleaning web can be controlled.   The image forming apparatus according to claim 1, further comprising a mechanism for separating the cleaning web.   5. The image forming apparatus according to claim 1, wherein the cleaning web winding amount can be controlled based on one or a plurality of control means.

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