JP2004045972A - Process cartridge, electrophotographic system, image forming method and intermediate transfer belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process cartridge forming satisfactory images and having excellent durability. <P>SOLUTION: The process cartridge satisfies all the relational expressions:(1≤RL/RH≤150, 1<ΔRL<100 and 1<ΔRH<100, 0.98≤LH/LL≤1.02, 0≤ΔLH/LH<0.005 and 0≤ΔLL/LL<0.005), wherein a volume resistivity of the intermediate transfer belt at 15°C×10% is RL; unevenness of the volume resistivity in one intermediate transfer belt is ΔRL; an average perimeter is LL and a right and left difference in perimeter is ΔLL; a volume resistivity of the intermediate belt at 30°C×80% is RH; unevenness of a volume resistivity in one intermediate transfer belt is ΔRH; and an average perimeter is LH and the right and left difference in the perimeter is ΔLH. <P>COPYRIGHT: (C)2004,JPO

Description

【０１４３】
【発明の効果】
本発明によれば、周囲の環境によらず安定した走行性が得られ、かつ良好な画像が形成でき、優れた耐久性を有する中間転写ベルト、中間転写ベルト−電子写真感光体一体カートリッジ、これを有する電子写真装置及び画像形成方法が得られる。
【図面の簡単な説明】
【図１】
電子写真装置の概略図である。
【図２】
電子写真感光体及び中間転写ベルトの一体構成の説明図である。
【図３】
中間転写ベルト成形装置の説明図である。
【図４】
中間転写ベルト成形装置の説明図である。
【図５】
プロセスカートリッジの説明図である。
【図６】
中間転写ユニットの説明図である。
【図７】
電子写真感光体ユニットの説明図である。
【図８】
プロセスカートリッジの着脱構成の説明図である。
【図９】
本発明の中間転写ベルトの内周長測定方法の概略図である。
【符号の説明】
１　電子写真感光体
２　一次帯電手段（帯電ローラー）
３　露光手段
５　中間転写ベルト
６　一次転写手段（一次転写ローラー）
７　二次転写手段（二次転写ローラー）
８　駆動ローラー
９　電荷付与手段（中間転写ベルトクリーニングローラー）
１０　転写材ガイド
１１　給紙ローラー
１２　テンションローラー（従動ローラー）
１３　電子写真感光体クリーニング手段
１５　定着手段
３０　（一次転写）バイアス電源
３１　（二次転写）バイアス電源
３２　一次帯電手段の電源
３３　バイアス電源
４１　第１の現像手段（イエロー色現像器）
４２　第２の現像手段（マゼンタ色現像器）
４３　第３の現像手段（シアン色現像器）
４４　第４の現像手段（ブラック色現像器）
４５　中間転写ベルトフレーム
５０　電子写真感光体ユニット
５１　中間転写ベルトユニット
５２　廃トナー容器
５３　クリーニングブレード
５４　スクリュー
５５　ドラムシャッター
５８　一次転写ローラー
５９　電子写真感光体フレーム
６０　電子写真装置本体の上蓋
７１　突起部
７２　位置決め穴
７２ａ　テーパー部
７３　フック部の爪
７４　ロック穴
１００　押し出し機
１０１　押し出し機
１０２　ホッパー
１０３　環状ダイス
１０４　気体導入路
１０５　外部冷却リング
１０６　安定板
１０７　ピンチローラー
１０８　カット装置
１１０　筒状フィルム
１２０　ローラー
１３０　ローラー
Ｐ　転写材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a process cartridge detachable from an electrophotographic apparatus such as a color copying machine or a color printer, an electrophotographic apparatus having the process cartridge, an image forming method using the electrophotographic apparatus, and a process cartridge mounted on the process cartridge. The present invention relates to an intermediate transfer belt.
[0002]
[Prior art]
An image forming apparatus using an intermediate transfer belt is a color image forming apparatus that sequentially transfers a plurality of component color images of color image information or multicolor image information and transfers the resulting color image or multicolor image to produce an image formed product. The present invention is effective as an apparatus or a multicolor image forming apparatus, or an image forming apparatus having a color image forming function or a multicolor image forming function.
[0003]
2. Description of the Related Art A color electrophotographic apparatus having an image forming apparatus using an intermediate transfer belt is a conventional technique in which a second image carrier is stuck or adsorbed on a transfer drum and an image is transferred from a photoconductor to the second image carrier. Compared with a color electrophotographic apparatus having the apparatus, for example, a transfer apparatus as described in Japanese Patent Application Laid-Open No. 63-301960, processing and control of the transfer material (for example, the The image can be transferred from the intermediate transfer belt without the need for holding the sheet, so that thin paper (40 g / m. ² Paper) to thick paper (200g / m ² This has the advantage that the second image carrier can be variously selected regardless of the width or length of the second image carrier.
[0004]
In addition, by adopting the intermediate transfer belt shape, the degree of freedom in arranging the image forming apparatus inside the image forming apparatus is increased as compared with a case where a rigid cylinder such as an intermediate transfer drum is used, and the apparatus body is effectively used by utilizing space. There is also an advantage that the size and cost can be reduced.
[0005]
However, the life of the intermediate transfer belt is shorter than that of the main body, and at present, replacement is essential. At the same time, it is necessary to install a waste toner container for collecting the developer (hereinafter, toner) remaining on the intermediate transfer belt and to process the waste toner container. In addition, in printers and copiers, many parts such as photoconductors, developing devices, and developers need to be replaced. Japanese Patent Laid-Open Publication No. Hei 8-137181 proposes a method in which these replacement parts are unitized and easily detached from the main body, in which the intermediate transfer belt and the sensitizer are arranged as independent units so as to be easily detachable from the main body. I have.
[0006]
However, this means requires a large number of replacement units, which complicates user operations. Further, since each unit is independently designed and arranged, problems such as an increase in the size of the main body and an increase in cost arise.
[0007]
As means for solving this problem, a means for simultaneously attaching and detaching the intermediate transfer belt and the photoreceptor, which are replacement parts, from the main body as an integrated unit and exchanging them is preferable. JP-A-6-110261, JP-A-10-177329 And Japanese Patent Application Laid-Open No. H11-30944.
[0008]
However, the method of configuring the intermediate transfer belt and the photoconductor as an integrated unit and making the intermediate transfer body and the photoconductor integral cartridge that can be easily attached to and detached from the main body is different from the case where the intermediate transfer belt is set when the main body is installed. In addition, there are some problems caused by the intermediate transfer belt.
[0009]
In recent years, full-color copying machines and full-color printers, which were high-priced and targeted only to a small number of corporate users, have recently been targeted at even small and medium-sized businesses and ordinary household users. Full-color copiers and printers for such users require ever more compact, low-cost, and high-speed main units.
[0010]
When the user base expands in this way, it is easily assumed that the user will be used not only in an air-conditioned office but also in any environment. Thus, even if the environment in which the apparatus main body is placed changes, it is required to obtain an image that does not change from that at normal temperature and normal humidity.
[0011]
For that purpose, it is required that the electrical resistance value of the intermediate transfer belt is stable even when the use environment of the apparatus changes, and it is necessary that a stable image is always obtained. Nevertheless, heretofore, no proposal has been made that mentions the electric resistance value of the intermediate transfer belt used in the intermediate transfer belt-photoreceptor integrated cartridge under each environment.
[0012]
Also, it is important that a change in resistance unevenness is small even when the use environment changes, in order to obtain a good image without transfer unevenness.
[0013]
On the other hand, in order to reduce the price of the device, the size of the main body of the device has been reduced, and the belt drive system has necessarily had a simple configuration. In such a case, it is difficult to stably obtain the belt driving speed. For this reason, it is required for the belt that the inner circumferential length of the belt does not change within a certain range even when the apparatus use environment changes.
[0014]
Needless to say, in order to obtain a stable running property of the belt, unevenness in the inner circumference of the belt should be minimized. However, this alone is not sufficient, and it is preferable that the difference between the left and right inner circumferential lengths be small, even if the environment changes, because more stable traveling performance can be obtained. Nevertheless, hitherto, no proposal has been made which mentions the inner peripheral length of the intermediate transfer belt under each environment.
[0015]
As described above, according to the related art, an intermediate transfer belt, an intermediate transfer belt-photoreceptor integrated cartridge, and an intermediate transfer belt that can stably run under any environment and can form a good image according to changes in the surrounding environment. A forming apparatus and an image forming method have not been obtained.
[0016]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to achieve stable running of the intermediate transfer belt, obtain good images, realize excellent durability, realize easy maintenance, reduce the size of the apparatus, A novel process cartridge capable of reducing costs and obtaining a good image similar to the initial one regardless of the surrounding use environment, an electrophotographic apparatus having the process cartridge, an image forming method using the electrophotographic apparatus, and the process An object of the present invention is to provide an intermediate transfer belt mounted on a cartridge.
[0017]
[Means for Solving the Problems]
The object of the present invention is to
A process cartridge detachable from the electrophotographic apparatus main body,
An electrophotographic photosensitive member for carrying a toner image,
An intermediate transfer belt having a contact portion with the electrophotographic photosensitive member,
Primary transfer means for primary transferring the toner image from the electrophotographic photosensitive member to the intermediate transfer belt at the corresponding contact portion;
In order to clean the intermediate transfer belt by returning the toner on the intermediate transfer belt to the electrophotographic photosensitive member at the corresponding contact portion, a polarity opposite to the polarity of the toner at the time of the primary transfer is applied to the toner on the intermediate transfer belt. Charge applying means for applying a charge of
Integrally supporting electrophotographic photosensitive member cleaning means for cleaning the electrophotographic photosensitive member,
An electrophotographic photoreceptor unit having the electrophotographic photoreceptor and an intermediate transfer belt unit having the intermediate transfer belt are separable, and a connecting means for connecting the electrophotographic photoreceptor unit and the intermediate transfer belt unit is provided. And
The volume resistivity of the intermediate transfer belt at 15 ° C. × 10% (relative humidity) is RL (Ω · cm), the volume resistivity unevenness in one intermediate transfer belt is ΔRL, the average circumference is LL (mm) and the circumference is The difference between the left and right lengths is ΔLL (mm),
The volume resistivity of the intermediate transfer belt at 30 ° C. × 80% (relative humidity) is RH (Ω · cm), the unevenness of the volume resistivity in one intermediate transfer belt is ΔRH, the average circumference is LH (mm) and the circumference is When the left-right difference is ΔLH (mm),
The problem can be solved by a process cartridge characterized by satisfying all of the following relational expressions.
1 ≦ RL / RH ≦ 150
1 <ΔRL <100 and 1 <ΔRH <100
0.98 ≦ LH / LL ≦ 1.02
0 ≦ ΔLH / LH <0.005 and 0 ≦ ΔLL / LL <0.005
[0018]
Further, the object of the present invention can be solved by an electrophotographic apparatus having the above process cartridge, an image forming method using the electrophotographic apparatus, and an intermediate transfer belt mounted on the process cartridge.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, as a result of intensive studies on simplification of maintenance, miniaturization of the main body and the cartridge, cost reduction, and improvement of the image quality, the use of the intermediate transfer belt-photoreceptor integrated cartridge and the addition of several measures By doing this, I reached my initial goal.
[0020]
First, in order to reduce the size and cost of the cartridge, the cleaning mechanism for the intermediate transfer belt employs a primary transfer simultaneous cleaning method in which the transfer residual toner is charged to the opposite polarity and is returned to the photoconductor at the same time as the primary transfer. Specifically, a voltage is applied to the cleaning roller, which is detachably disposed on the intermediate transfer belt, to apply a charge of a polarity opposite to that at the time of the primary transfer to the secondary transfer residual toner. It is a means of returning to the body. Of course, the means for charging the toner to the opposite polarity may be a roller other than a roller, for example, a corona charger, a blade, or the like, as long as the charge can be applied to the transfer residual toner on the intermediate transfer belt. You can use any means. The toner returned to the photoconductor from the intermediate transfer belt is removed by a photoconductor cleaning mechanism such as a cleaning blade. According to this method, a cleaning blade or the like is disposed on both the photosensitive member and the intermediate transfer belt, and a large effect is achieved in reducing the size and cost of the cartridge as compared with a method in which a waste toner feeding mechanism and a container are provided.
[0021]
Next, in the present invention, it is necessary that 1 ≦ RL / RH ≦ 150. It is preferable that the fluctuation of the resistance of the intermediate transfer belt be minimized depending on the use environment of the apparatus. If the fluctuation is large, an image defect occurs. That is, if the volume resistivity is lowered under high temperature and high humidity, a sufficient transfer electric field cannot be obtained, and an image may be missing or rough. On the other hand, if the volume resistivity becomes too high at low temperature and low humidity, the transfer voltage must be increased, which results in an increase in the size of the power supply and an increase in cost.
[0022]
Next, in the present invention, it is necessary that 1 <ΔRL <100 and 1 <ΔRH <100. Under low temperature and low humidity, and under high temperature and high humidity, those having less resistance unevenness are preferable because good images can be obtained. If the resistance non-uniformity is 100 or more, transfer non-uniformity occurs, and the color non-uniformity appears on the image.
[0023]
Further, in the present invention, it is necessary that 0.98 ≦ LH / LL ≦ 1.02. If the inner peripheral length of the belt fluctuates greatly due to a change in the use environment of the apparatus, the running property of the belt is impaired, and a good image cannot be obtained. In other words, in an environment of low temperature and low humidity (15 ° C. × 10% (relative humidity)), the circumference of the belt becomes short, and the belt is over-tensioned, hindering smooth rotation or causing breakage of the belt. In some cases, this is not preferred. On the other hand, in an environment of high temperature and high humidity (30 ° C./80%), the circumference of the belt becomes longer, the tension of the belt decreases, causing color shift, lowering the image quality, and finally reducing the image quality. In some cases, slippage occurs with the drive roller, and the drive becomes impossible.
[0024]
Next, in the present invention, it is necessary that 0 ≦ ΔLH / LH <0.005 and 0 ≦ ΔLL / LL <0.005. In order to obtain stable running performance, it is necessary to make the difference between the left and right of the circumference of the belt itself small, and to make no difference in the left and right circumference between low temperature and low humidity and high temperature and high humidity. is important. If the difference between the left and right circumferences and the difference in the environment exceed the range of the present invention, stable traveling performance cannot be obtained.
[0025]
As described above, even if only the electrical characteristics can be satisfied, if the mechanical characteristics cannot be satisfied, a stable good image cannot be obtained. Conversely, if only the mechanical characteristics can be satisfied, a good image cannot be obtained. A good image can be obtained only when the two characteristics are combined, and the object of the present invention can be achieved only when the characteristics of both are suppressed to the following ranges.
[0026]
On the other hand, in the case where the intermediate transfer belt and the photoreceptor are integrated, the cartridge is treated as a consumable item. Therefore, it is desired that the components constituting the photoconductor be inexpensive. Of course, both the photoconductor and the intermediate transfer belt should be manufactured at low cost. Usually, the photosensitive member is provided in the form of a flexible belt, or the photosensitive member is provided in the form of a rigid drum. A drum-shaped one is preferable in that the drive mechanism is simple, suitable for miniaturization, and can be manufactured at lower cost. The material is preferably made of aluminum from the viewpoint of cost, and the size thereof is preferably 60 mm or less in terms of further miniaturization. Further, in consideration of cost, environmental load, and the like, the photosensitive member is preferably an organic photosensitive drum.
[0027]
For the same purpose, a system in which the intermediate transfer belt is stretched with at least two or more rollers is preferable because the mechanism is simple, the number of parts is reduced, and the size is reduced.
[0028]
The thickness of the intermediate transfer belt is preferably in the range of 40 μm to 300 μm. If it is less than 40 μm, the molding stability is lacking, the thickness tends to be uneven, the durability is insufficient, and the belt may be broken or cracked. On the other hand, if the thickness exceeds 300 μm, the amount of material increases and the cost increases. In addition, the peripheral speed difference between the inner surface and the outer surface at the stretch shaft portion of the printer or the like increases, and problems such as image scattering due to contraction of the outer surface are likely to occur. There is also a problem in that the bending durability is lowered and the rigidity of the belt becomes too high, so that the driving torque is increased, which leads to an increase in the size of the main body and an increase in cost.
[0029]
Further, the width of the intermediate transfer belt is preferably in the range of 100 mm to 500 mm. If it is less than 100 mm, there is too much restriction on the paper size that can be handled, and if it exceeds 500 mm, the size of the apparatus main body is undesirably increased.
[0030]
The means for obtaining the characteristics of the present invention may be adjusted so as to fall within the scope of the present invention by selecting the material used as the raw material of the intermediate transfer belt and various additives.
[0031]
Materials constituting the intermediate transfer belt used in the process cartridge and the electrophotographic apparatus of the present invention are roughly classified into a main binder and an electric resistance controlling agent.
[0032]
As the binder, a resin, rubber, or elastomer can be used, and a thermoplastic resin or a thermosetting resin is preferably used, and a thermoplastic resin is particularly preferable.
[0033]
For example, olefin-based resins such as polyethylene and polypropylene, polystyrene-based resins, acrylic resins, polyester resins, polycarbonates, sulfur-containing resins such as polysulfone, polyethersulfone, and polyphenylene sulfide, polyvinylidene fluoride, and polyethylene-tetrafluoroethylene copolymer One or two or more types of fluorine-containing resins such as coalesced resins, polyurethane resins, silicone resins, ketone resins, polyvinylidene chloride, thermoplastic polyimide resins, polyamide resins, modified polyphenylene oxide resins, and various modified resins and copolymers thereof Can be used. However, the material is not limited to the above.
[0034]
Next, additives to be mixed to adjust the electric resistance value of the electrophotographic belt of the present invention are not particularly limited, but carbon black or various conductive metals may be used as the conductive filler for adjusting the resistance. Non-filler-based resistance modifiers include low-molecular-weight ionic conductive materials such as metal salts and glycols, antistatic resins containing ether bonds and hydroxyl groups in the molecule, or organic compounds that exhibit electronic conductivity. High molecular compounds and the like. What is required here is a dispersion state of each additive and components constituting the intermediate transfer belt such as a resin, and the effects of the present invention cannot be obtained if agglomeration of particles or extreme separation of some components has occurred. The choice of material and dispersing means is important.
[0035]
Among the above-mentioned resistance modifiers, an antistatic resin is particularly useful, and when a polyetheresteramide resin, which is a copolymer of a polyether component and a polyamide component, is used, the compatibility with the resin for forming an intermediate transfer belt is improved. This is preferable because uniformity of electric resistance can be obtained. Also, there is little change in the electric resistance value due to environmental changes. However, the present invention is not limited to the above materials.
[0036]
In addition, a reinforcing effect is obtained by mixing a filler such as inorganic particles as an additive, for example, and the rate of change of the belt inner peripheral length under a low-temperature low-humidity environment and a high-temperature high-humidity environment is reduced. At this time, the volume resistivity of the belt and the rate of change of the inner circumferential length of the belt can be adjusted to the range described in the present invention by selecting the material and amount of the filler and the type of the resin.
[0037]
However, if the characteristics of the present invention can be obtained only by the main binder and the electric resistance controlling agent, it is not necessary to add an additive or the like.
[0038]
Hereinafter, an example of a method for manufacturing the intermediate transfer belt used in the present invention will be described. However, this does not limit the present invention at all.
[0039]
FIG. 3 shows an example of an apparatus for manufacturing an intermediate transfer belt. This device has an extruder, an extrusion die, and a gas blowing device.
[0040]
First, after preliminarily mixing a molding resin, a conductive agent, an additive, and the like based on a desired formulation, a kneading-dispersed molding material is put into a hopper 102 provided in an extruder 100.
[0041]
In the extruder 100, the set temperature and the screw configuration of the extruder are selected so that the raw material for molding has a melt viscosity that allows the belt to be formed in a subsequent step, and the raw materials are uniformly dispersed. The raw material for molding is melted and kneaded in the extruder 100 to form a melt and enter the annular die 103.
[0042]
The annular die 103 is provided with a gas introduction passage 104, and when the gas is blown into the center of the annular die 103 from the gas introduction passage 104, the melt that has passed through the die 103 expands and expands in the radial direction, and Film 110.
[0043]
The gas blown at this time can be selected from nitrogen, carbon dioxide, argon, and the like, in addition to air.
[0044]
The expanded molded body is pulled up while being cooled by the external cooling ring 105. Normally, in the inflation device, a method is employed in which the tube is crushed from the left and right by the stabilizer 106, folded into a sheet shape, pinched by the pinch roller 107 so that the air inside does not escape, and pulled out at a constant speed.
[0045]
Next, the taken-off film is cut by the cutting device 108 to obtain a cylindrical film having a desired size.
[0046]
Next, the cylindrical film is processed using a mold for the purpose of adjusting the surface smoothness and dimensions, and removing the folds formed on the film during molding.
[0047]
Specifically, there is a method of using a set of cylindrical molds having different diameters made of materials having different thermal expansion coefficients.
[0048]
The coefficient of thermal expansion of the small-diameter cylindrical type (inner die) should be larger than that of the large-diameter cylindrical type (outer die). Is inserted into the outer mold so that the tubular film is sandwiched between the inner mold and the outer mold. The gap between the molds is determined by calculating the difference between the heating temperature and the coefficient of thermal expansion between the inner mold and the outer mold, and the required pressure.
[0049]
The mold set in the order of inner mold, cylindrical film, and outer mold is heated to around the softening point temperature of the resin. Due to the heating, the inner mold having a large thermal expansion coefficient expands more than the outer mold, and a uniform pressure is applied to the entire surface of the tubular film. At this time, the outer circle of the resin film that has reached the vicinity of the softening point is pressed against the inner surface of the outer mold that has been processed smoothly, and the smoothness of the resin film surface is improved. Thereafter, the film is cooled and the film is removed from the mold, whereby a smooth surface property can be obtained.
[0050]
Thereafter, if necessary, a reinforcing member, a guide member, and a position detecting member are attached and precision cut is performed to manufacture an intermediate transfer belt.
[0051]
Although the description has been made with respect to a single-layer belt, in the case of two layers, an extruder 101 is additionally arranged as shown in FIG. To the extruders 100 and 101, and the two layers are simultaneously expanded and expanded to obtain a two-layer belt.
[0052]
Of course, when there are three or more layers, an extruder may be prepared according to the number of layers.
[0053]
As described above, according to the method of manufacturing the intermediate transfer belt, not only a single-layer intermediate transfer belt but also a multilayer intermediate transfer belt can be formed in a single-step process with high dimensional accuracy in a short time. The fact that short-time molding is possible means that mass production and low-cost production are possible.
[0054]
The ratio of the thickness of the annular die to the thickness of the molded cylindrical film, that is, the ratio of the thickness of the molded cylindrical film to the width of the gap (slit) of the annular die is as follows: It is preferably at most 1/3, more preferably at most 1/5.
[0055]
Similarly, if the ratio of the outer diameter of the cylindrical film 110 to the outer diameter of the die slit of the annular die 103 is expressed as a percentage, the ratio of the diameter of the annular die to the diameter of the formed cylindrical film is 50% to 50%. A range of 400% is preferred.
[0056]
These indicate the stretched state of the material. If the thickness ratio is greater than 1/3, the stretching is insufficient, and problems such as a decrease in strength and unevenness in resistance and thickness may occur.
[0057]
On the other hand, when the outer diameter exceeds 400%, the film is excessively stretched, and the molding stability is reduced and it is difficult to secure the thickness required for the present invention. If it is less than 50%, stretching in the circumferential direction is insufficient, and problems such as a decrease in strength and unevenness in resistance and thickness occur.
[0058]
Next, an example of an electrophotographic apparatus using the intermediate transfer belt-electrophotographic photosensitive member integrated cartridge of the present invention is shown in FIG.
[0059]
FIG. 1 shows a color electrophotographic apparatus such as a color copying machine or a color laser beam printer.
[0060]
Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (photosensitive drum) repeatedly used as a first image carrier, and is driven to rotate at a predetermined peripheral speed (process speed) in a clockwise direction indicated by an arrow.
[0061]
The electrophotographic photosensitive member 1 is uniformly charged to a predetermined polarity and potential by a primary charging means (charging roller) 2 during the rotation process. Reference numeral 32 denotes a power supply for the primary charging means 2, which applies an alternating current to a direct current, but may apply only a direct current.
[0062]
Next, exposure by exposure means 3 (such as a color separation / condensing exposure optical system for a color original image, a scanning exposure system using a laser scanner for outputting a laser beam modulated in accordance with a time-series electric digital pixel signal of image information, etc.) is performed. Upon reception, an electrostatic latent image corresponding to a first color component image (for example, a yellow color component image) of the target color image is formed.
[0063]
Next, the electrostatic latent image is developed by the first developing means (yellow color developing device 41) with the yellow toner Y as the first color. At this time, the developing units of the second to fourth developing units (the magenta developing unit 42, the cyan developing unit 43, and the black developing unit 44) are in the operation-off state. No effect, the first color yellow toner image is not affected by the second to fourth developing units.
[0064]
The intermediate transfer belt 5 is rotated clockwise at the same peripheral speed as the electrophotographic photosensitive member 1.
[0065]
While the first color yellow toner image formed and carried on the electrophotographic photosensitive member 1 passes through the contact portion between the electrophotographic photosensitive member 1 and the intermediate belt 5, a roller-shaped primary transfer unit (primary transfer) is used. The primary transfer is sequentially performed on the outer peripheral surface of the intermediate transfer belt 5 by an electric field formed by a primary transfer bias applied to the intermediate transfer belt 5 from the roller 6.
[0066]
After the transfer of the first color yellow toner image corresponding to the intermediate transfer belt 5, the surface of the electrophotographic photosensitive member 1 is cleaned by the electrophotographic photosensitive member cleaning unit 13.
[0067]
Hereinafter, similarly, the magenta toner image of the second color, the cyan toner image of the third color, and the black toner image of the fourth color are sequentially superimposed on the intermediate transfer belt 5 and transferred, so that the composite color corresponding to the target color image is obtained. A toner image is formed.
[0068]
Reference numeral 7 denotes a roller-shaped secondary transfer means (secondary transfer roller), which is supported in parallel with the drive roller 8 and is disposed on the lower surface of the intermediate transfer belt 5 so as to be separated therefrom.
[0069]
A primary transfer bias for sequentially superimposing transfer of the first to fourth color toner images from the electrophotographic photosensitive member 1 to the intermediate transfer belt 5 is applied from a bias power supply 30 with a polarity (+) opposite to that of the toner. The applied voltage is, for example, in the range of +100 V to 2 kV.
[0070]
In the primary transfer process of the first to third color toner images from the electrophotographic photosensitive member 1 to the intermediate transfer belt 5, the secondary transfer means 7 can be separated from the intermediate transfer belt 5.
[0071]
The transfer of the composite color toner image transferred onto the intermediate transfer belt 5 to the transfer material P, which is the second image carrier, is performed by the secondary transfer unit 7 being in contact with the intermediate transfer belt 5 and the paper feed roller The transfer material P is fed at a predetermined timing from the transfer material 11 to the contact portion between the intermediate transfer belt 5 and the secondary transfer means 7 through the transfer material guide 10, and the secondary transfer bias is applied from the bias power supply 31 to the secondary transfer. Applied to means 7. By this secondary transfer bias, the composite color toner image is secondarily transferred from the intermediate transfer belt 5 to the transfer material P as the second image carrier. The transfer material P to which the toner image has been transferred is introduced into the fixing unit 15 and is fixed by heating.
[0072]
After the transfer of the image to the transfer material P is completed, the intermediate transfer belt 5 is brought into contact with a charge applying means 9 which is freely detachable from the intermediate transfer belt 5, and the transfer is performed by applying a bias having a polarity opposite to that of the electrophotographic photosensitive member 1. The transfer residual toner remaining on the intermediate transfer belt 5 without being transferred to the material P is given a charge having a polarity opposite to that of the primary transfer. 33 is a bias power supply. Here, alternating current is superimposed on direct current and applied.
[0073]
The transfer residual toner charged to a polarity opposite to that at the time of the primary transfer is electrostatically transferred to the electrophotographic photosensitive member 1 in the vicinity of the contact portion with the electrophotographic photosensitive member 1 and in the vicinity thereof, thereby forming the intermediate transfer belt. Will be cleaned. Since this step can be performed simultaneously with the primary transfer, a decrease in throughput does not occur.
[0074]
Next, the intermediate transfer belt-electrophotographic photosensitive member integrated cartridge of the present invention will be described.
[0075]
As shown in FIG. 2, the process cartridge of the present invention includes at least the electrophotographic photosensitive member 1, the intermediate transfer belt 5, the primary transfer unit 6, the charge applying unit 9, and the electrophotographic photosensitive member cleaning unit 13. It is configured to be integrally supported and can be easily attached to and detached from the main body of the electrophotographic apparatus.
[0076]
As described above, the cleaning of the intermediate transfer belt in the process cartridge and the electrophotographic apparatus of the present invention is performed by charging the transfer residual toner to a polarity opposite to that of the primary transfer, and by using the electrophotographic photosensitive member at the contact portion with the electrophotographic photosensitive member. In this figure, a roller-shaped charge applying means 9 of a medium-resistance elastic body is provided.
[0077]
The cleaning of the electrophotographic photosensitive member is preferably performed by using a blade, and the figure shows a mode in which the blade is used for cleaning the electrophotographic photosensitive member.
[0078]
The process cartridge shown in FIG. 2 also integrally supports a waste toner container, and the transfer residual toner on both the intermediate transfer belt and the electrophotographic photosensitive member is discarded at the same time when the cartridge is replaced. ing.
[0079]
Further, the intermediate transfer belt is stretched by two rollers 8 and 12 to reduce the number of parts and reduce the size. Here, reference numeral 8 denotes a driving roller, and at the same time, a counter roller of a charge applying means (intermediate transfer belt cleaning roller). The tension roller (driven roller) 12 that rotates following the intermediate transfer belt has a sliding mechanism, and is pressed against the intermediate transfer belt by a compression spring in the direction of the arrow to apply tension to the intermediate transfer belt. The slide width is preferably 1 to 5 mm, and the total pressure of the spring is preferably 5 to 100 N. Further, the electrophotographic photosensitive member 1 and the driving roller 8 have a coupling (not shown), and a rotational driving force is transmitted from the main body.
[0080]
Hereinafter, methods for measuring various physical properties according to the present invention will be described.
[0081]
<Measuring method of circumference>
After leaving the intermediate transfer belt in an environment of 30 ° C. × 80% or 15 ° C. × 10% (relative humidity) without applying tension for 12 hours or more, as shown in FIG. Stretch at 130 and measure the distance between the rollers. When the outer diameters of the rollers are equal, the inner circumferential length of the belt is calculated by the following equation.
[0082]
Belt inner circumference = (distance from center of one roller to center of other roller) x 2 + outer circumference of roller
[0083]
The difference between the inner peripheral length at one end in the belt longitudinal direction and the inner peripheral length at the other end measured in this way is defined as the left-right difference of the inner peripheral length of the belt. Since the left-right difference of the inner peripheral length changes depending on the width of the belt, the measurement is performed with the width at which the intermediate transfer belt is actually used as a product. In addition, the measurement is performed in a state in which a reinforcing tape, a meandering prevention member, and the like are not attached to the belt end. If measurement is inevitable, the measurement is performed with these effects negligible. For example, when the meandering prevention member is attached to the end of the inner surface of the belt, the roller is measured by digging a groove larger than the cross-sectional shape of the meandering prevention member.
[0084]
At this time, the outer diameter of the roller is not particularly limited as long as the two rollers can fit in accordance with the inner peripheral length of the belt, but it is usually preferable to use an outer diameter of about 20 mm to 60 mm. . Also. The length of the roller is longer than the width of the belt.
[0085]
At this time, tension is applied to the belt by utilizing the own weight of the roller itself, hanging weights at both ends of the roller, pressing or pulling using a spring or the like. The applied load shall be 20N, and the error shall be within ± 10%. At this time, the load applied to the belt is not evenly distributed to the left and right, and is applied substantially evenly.
[0086]
<Volume resistance measurement method>
The measurement sample is previously left in an environment of 30 ° C. × 80% or 15 ° C. × 10% for 12 hours or more. The measuring device uses an ultra-high resistance meter R8340A (manufactured by Advantest) as a resistance meter, and the sample box uses a sample box TR42 (manufactured by Advantest) for measuring an ultra-high resistance. 41 mm and outer diameter 49 mm.
[0087]
The sample is created as follows. First, the intermediate transfer belt is cut into a circle having a diameter of 56 mm by a punching machine or a sharp blade. One surface of the cut circular piece is provided with electrodes on the entire surface thereof by a Pt-Pd vapor-deposited film, and the other surface is provided by a Pt-Pd vapor-deposited film on a main electrode having a diameter of 25 mm and a guard electrode having an inner diameter of 38 mm and an outer diameter of 50 mm. The Pt-Pd vapor-deposited film can be obtained by performing a vapor-deposition operation with mild sputter E1030 (manufactured by Hitachi, Ltd.) for 2 minutes. The sample after the vapor deposition operation is used as a measurement sample.
[0088]
The measurement is performed for 10 seconds for discharging, 30 seconds for charging, and 30 seconds for measuring, and is performed at an applied voltage of 100 V.
[0089]
<Volume resistivity unevenness measurement>
Sampling was performed from a total of eight locations at four locations at approximately equal intervals in the circumferential direction of the belt at a portion (two locations) of 50 mm in the axial direction from both ends of the belt, and the volume resistivity was measured as described above. The minimum value is defined as the unevenness of the volume resistivity within one belt.
[0090]
Hereinafter, the present invention will be described in detail with reference to examples. Parts in the examples are parts by mass.
[0091]
[Example 1]
[0092]
Formula 1
71.5 parts of polyvinylidene fluoride resin (PVDF)
Polyether-containing antistatic resin (polyetheresteramide) 8 parts
Sulfonate surfactant 0.5 part
Metal oxide particles (zinc oxide (ZnO) particles) 20 parts
[0093]
The above composition was melt-kneaded at 210 ° C. with a twin-screw extruder to mix the respective materials, extruded with a strand having a diameter of about 2 mm, and cut into pellets. This is designated as molding material 1. Next, in the forming apparatus of FIG. 3, the forming die 103 was a single-layer annular die having a die slit diameter of 100 mm. The die slit was 0.8 mm. The molding material 1 sufficiently heated and dried was put into the material hopper 102 of the molding apparatus, heated and melted, and extruded into a cylindrical shape at 210 ° C. from a die. An external cooling ring 105 is provided around the die, and air is blown from the periphery to the extruded film to perform cooling. Air was blown into the extruded cylindrical film from the gas introduction passage 104 to expand and expand to a diameter of 140 mm, and then continuously taken out at a constant speed by a take-off device. The ratio of the diameter of the annular die 103 to the diameter of the formed cylindrical film is 140%. The introduction of air is stopped when the diameter reaches a desired value. Further, the tubular film is cut by the cutting device 108 following the pinch roller. After the thickness was stabilized, it was cut at a length of 290 mm to form a tubular film 110.
[0094]
The cylindrical film 110 was subjected to size adjustment, surface smoothness adjustment, and fold removal using a set of cylindrical bodies made of metals having different coefficients of thermal expansion. A cylindrical film (inner mold) having a high coefficient of thermal expansion is covered with the cylindrical film 110, and the cylindrical film 110 is inserted into a cylindrical body (outer mold) having an inner surface smoothed, and heated at 170 ° C. for 20 minutes. After cooling to room temperature, the tubular film was removed from the inner and outer molds, and both ends were cut to produce an intermediate transfer belt (1) having a width of 250 mm.
[0095]
The belt had a thickness of 86 μm.
[0096]
<Measurement of volume resistivity of intermediate transfer belt>
Volume resistivity (RL) and its unevenness (ΔRL) under an environment of 15 ° C. × 10%
RL: 1.13 × 10 ¹² , ΔRL: 1.4
Volume resistivity (RH) and its unevenness (ΔRH) in an environment of 30 ° C. × 80%
RH: 1.28 × 10 ¹⁰ , ΔRH: 2.2
[0097]
<Measurement of inner circumference of intermediate transfer belt>
First, the inner peripheral length of the intermediate transfer belt obtained as described above and the left-right difference thereof were measured in an environment of 30 ° C. × 80% (relative humidity) as shown in FIG. 9, and then 15 ° C. × 10% ( (Relative humidity), the inner circumference and the left-right difference were measured in the same manner. The measurement results are as follows.
[0098]
Average circumference (LL) and left-right difference (ΔLL) in an environment of 15 ° C. × 10%
LL: 438.55 mm, ΔLL: 0.02 mm
Average circumference (LH) and left-right difference (ΔLH) in an environment of 30 ° C. × 80%
LH: 440.75 mm, ΔLH: 0.10 mm
[0099]
Next, the process cartridge used in this embodiment will be described.
[0100]
FIG. 5 shows a process cartridge formed by connecting an electrophotographic photosensitive member unit having an electrophotographic photosensitive member and an intermediate transfer belt unit having an intermediate transfer belt.
[0101]
6 and 7 show an intermediate transfer belt unit and an electrophotographic photosensitive member unit, respectively.
[0102]
The frame configuration is roughly divided into two.
[0103]
5, an electrophotographic photoreceptor 1, a charging roller 2, a cleaning blade 53, a screw 54, and a drum shutter 55 are used as main components in an electrophotographic photoreceptor frame 59 which is integrated with the waste toner container 52 also shown in FIG. The intermediate transfer belt 5 is stretched by the driving roller 8 and the driven roller 12 on the intermediate transfer belt frame 45 shown in FIG. 6 and the electrophotographic photosensitive member 1 (see FIG. 7). Is divided into a primary transfer roller 58 inside the intermediate transfer belt facing the intermediate transfer belt, and an intermediate transfer belt unit 51 in which a charge applying means (intermediate transfer belt cleaning roller) 9 is also arranged on the drive roller 8.
[0104]
In FIG. 5, the two units are such that projections 71 provided on both left and right ends of an electrophotographic photosensitive member frame 59 are inserted into positioning holes 72 (FIG. 6) provided in the intermediate transfer belt frame 45, respectively. A hook 73 of a snap-fit type hook portion provided at the center in the width direction of the electrophotographic photosensitive member frame 59 is fitted and connected to a lock hole 74 of the intermediate transfer frame 45.
[0105]
Here, the positioning holes 72 and the lock holes 74 provided in the intermediate transfer frame 45 are formed by holes larger than the protrusions 71 and the hook claws 73 provided in the electrophotographic photosensitive member frame 59 by a predetermined amount. In addition, a predetermined amount of relative position movement is possible between the electrophotographic photosensitive member unit 50 (FIG. 7) and the intermediate transfer belt unit 51 (FIG. 6).
[0106]
Further, a tapered portion 72a is provided in the positioning hole 72 to facilitate attachment and detachment.
[0107]
In FIG. 7, the hook claw 73 of the electrophotographic photosensitive member unit 50 is pushed out of the lock hole 74 of the intermediate transfer belt unit 51, and the electrophotographic photosensitive member unit 50 is rotated, so that the electrophotographic photosensitive member unit 50 is rotated as shown in FIGS. It can be divided into a photoreceptor unit and an intermediate transfer belt unit.
[0108]
At the time of connection, contrary to the above, the projection 71 of the electrophotographic photosensitive member unit 50 is inserted into the positioning hole 72 of the intermediate transfer belt unit 51, and rotated in the direction opposite to the direction at the time of removal, so that the hook claw 73 is By pushing the two units into the lock holes 74, the two units are connected.
[0109]
FIG. 8 shows how the process cartridge of the present invention is attached to and detached from an electrophotographic apparatus.
[0110]
Just by opening the top cover 60 of the main body of the electrophotographic apparatus, the process cartridge can be easily attached and detached as in the case of a conventional black-and-white laser beam printer, and maintenance such as jam processing and process cartridge replacement can be easily performed.
[0111]
The electrophotographic photoreceptors used in the image evaluation of the present invention are as follows.
[0112]
<Preparation of electrophotographic photoreceptor>
47mm outside diameter aluminum cylinder (volume resistivity 10 ^-2 Ω · cm) was used as a support, and a 5% by mass methanol solution of a solvent-soluble polyamide was applied by dip coating to provide a subbing layer having a thickness of 1 μm.
[0113]
Next, 10 parts of a bisazo pigment, 5 parts of polyvinyl butyral, and 50 parts of cyclohexanone were dispersed in a sand mill using glass beads having a diameter of 1 mm for 20 hours. 100 parts of methyl ethyl ketone was added to this dispersion, and the dispersion was applied onto the undercoat layer to form a 0.1 μm-thick charge generation layer.
[0114]
Next, 10 parts of a bisphenol Z-type polycarbonate and 10 parts of a hydrazone compound are dissolved in 65 parts of monochlorobenzene, and immersion-coated on the charge generation layer to form a 20 μm-thick charge transport layer to obtain an electrophotographic photoreceptor. Was.
[0115]
<Image evaluation>
A meandering preventing member and a position detecting member were attached to the intermediate transfer belt 1 and incorporated into the intermediate transfer belt-photoreceptor integrated cartridge shown in FIG. At this time, the spring pressure of the tension roller was 20 N in total on the left and right sides, the slide amount was 2.5 mm, and the diameter of the tension roller and the drive roller was φ28 mm. Subsequently, it was allowed to stand for 24 hours in an environment of 30 ° C./80%, and then set in the electrophotographic apparatus of FIG. ² A full color image print test was performed on paper. The developing device used at this time was a 600 dpi digital laser system. When the obtained image was visually evaluated, a satisfactory full-color image free from problems such as color shift, color unevenness and transfer omission was obtained. Subsequently, after standing for 24 hours in an environment of 15 ° C. × 10%, image evaluation was performed in the same manner.
[0116]
Table 1 summarizes these results.
[0117]
[Example 2]
An intermediate transfer belt (2) was formed in the same manner as in Example 1 except that the compounding ratio was changed as follows and an intermediate transfer belt having a diameter of 230 mm and a width of 320 mm was used.
[0118]
Formula 2
89.3 parts of PVDF
Polyether-containing antistatic resin (polyetheresteramide) 10 parts
0.7 parts of sulfonate surfactant
[0119]
For the intermediate transfer belt (2), the measurement of the inner circumference and the image print test were performed in the same manner as in Example 1. The result of the print test using the intermediate transfer belt (2) was as good as in Example 1. Also, the running property of the belt was stable.
[0120]
The belt had a thickness of 83 μm.
[0121]
The results are summarized in Table 1.
[0122]
[Example 3]
An intermediate transfer belt (3) was formed in the same manner as in Example 1 except that the mixing ratio was changed as follows.
[0123]
Formula 3
87.5 parts of PVDF
Polyether-containing antistatic resin (polyetheresteramide) 12 parts
Sulfonate surfactant 0.5 part
[0124]
The obtained intermediate transfer belt was evaluated in the same manner as in Example 1.
[0125]
The results are summarized in Table 1.
[0126]
[Comparative Example 1]
A comparative intermediate transfer belt (1) was formed in the same manner as in Example 1 except that the mixing ratio was changed as follows.
[0127]
Formula 4
ABS resin 80 parts
20 parts of polyether-containing antistatic resin (polyetheresteramide)
[0128]
The obtained intermediate transfer belt was evaluated in the same manner as in Example 1.
[0129]
The results are summarized in Table 1.
[0130]
[Comparative Example 2]
A comparative intermediate transfer belt (2) was formed in the same manner as in Example 1 except that the mixing ratio was changed as follows.
[0131]
Formula 5
PVDF 88 parts
Polyether-containing antistatic resin (polyetheresteramide) 8 parts
4 parts of carbon black
[0132]
The obtained intermediate transfer belt was evaluated in the same manner as in Example 1.
[0133]
Although the running properties of the obtained belt were excellent, the unevenness of the volume resistivity was large, and a leak occurred at a portion considered to be caused by the aggregation of carbon black, and image defects were observed.
[0134]
The results are summarized in Table 1.
[0135]
[Comparative Example 3]
A comparative intermediate transfer belt (3) was formed in the same manner as in Example 1 except that the mixing ratio was changed as follows.
[0136]
Formula 6
67 parts of ethylene-vinyl acetate copolymer (EVOH)
30 parts of polyether-containing antistatic resin (polyetheresteramide)
3 parts of fluorinated surfactant
[0137]
The obtained intermediate transfer belt was evaluated in the same manner as in Example 1.
[0138]
There is a large difference between the perimeter in an environment of 15 ° C. × 10% and the perimeter in an environment of 30 ° C. × 80%. Was something.
[0139]
The results are summarized in Table 1.
[0140]
[Comparative Example 4]
With the same composition as in Example 1, a comparative intermediate transfer belt (4) was formed. The difference between the left and right circumferences of the resulting belt was very poor.
[0141]
The comparative intermediate transfer belt (4) was evaluated in the same manner as in Example 1. Table 1 summarizes the evaluation results.
[0142]
[Table 1]

[0143]
【The invention's effect】
According to the present invention, an intermediate transfer belt, an intermediate transfer belt and an electrophotographic photoreceptor integrated cartridge, which can obtain stable running properties regardless of the surrounding environment, can form a good image, and have excellent durability, And an image forming method having the following.
[Brief description of the drawings]
FIG.
It is a schematic diagram of an electrophotographic apparatus.
FIG. 2
FIG. 2 is an explanatory diagram of an integrated configuration of an electrophotographic photosensitive member and an intermediate transfer belt.
FIG. 3
FIG. 3 is an explanatory diagram of an intermediate transfer belt forming device.
FIG. 4
FIG. 3 is an explanatory diagram of an intermediate transfer belt forming device.
FIG. 5
FIG. 4 is an explanatory diagram of a process cartridge.
FIG. 6
FIG. 4 is an explanatory diagram of an intermediate transfer unit.
FIG. 7
FIG. 3 is an explanatory diagram of an electrophotographic photosensitive member unit.
FIG. 8
FIG. 4 is an explanatory diagram of a configuration for attaching and detaching a process cartridge.
FIG. 9
FIG. 4 is a schematic view of a method for measuring an inner circumferential length of an intermediate transfer belt according to the present invention.
[Explanation of symbols]
1. Electrophotographic photoreceptor
2 Primary charging means (charging roller)
3 Exposure means
5 Intermediate transfer belt
6. Primary transfer means (primary transfer roller)
7 Secondary transfer means (secondary transfer roller)
8 Drive roller
9 Charge applying means (intermediate transfer belt cleaning roller)
10 Transfer material guide
11 Paper feed roller
12 tension roller (driven roller)
13 Electrophotographic photosensitive member cleaning means
15 Fixing means
30 (primary transfer) bias power supply
31 (Secondary transfer) bias power supply
32 Power supply for primary charging means
33 bias power supply
41 first developing means (yellow developing device)
42 Second developing means (magenta color developing device)
43 third developing means (cyan developing device)
44 fourth developing means (black color developing device)
45 Intermediate transfer belt frame
50 Electrophotographic photoreceptor unit
51 Intermediate transfer belt unit
52 Waste Toner Container
53 Cleaning blade
54 screws
55 drum shutter
58 Primary Transfer Roller
59 Electrophotographic photoreceptor frame
60 Top cover of electrophotographic device
71 Projection
72 Positioning hole
72a taper part
73 Hook Claw
74 Lock hole
100 extruder
101 Extruder
102 Hopper
103 annular die
104 Gas introduction path
105 External cooling ring
106 Stabilizer
107 Pinch roller
108 Cutting device
110 tubular film
120 rollers
130 rollers
P transfer material

Claims (16)

A process cartridge detachable from the electrophotographic apparatus main body,
An electrophotographic photosensitive member for carrying a toner image,
An intermediate transfer belt having a contact portion with the electrophotographic photosensitive member,
Primary transfer means for primary transferring the toner image from the electrophotographic photosensitive member to the intermediate transfer belt at the corresponding contact portion;
In order to clean the intermediate transfer belt by returning the toner on the intermediate transfer belt to the electrophotographic photosensitive member at the corresponding contact portion, a polarity opposite to the polarity of the toner at the time of the primary transfer is applied to the toner on the intermediate transfer belt. Charge applying means for applying a charge of
Integrally supporting electrophotographic photosensitive member cleaning means for cleaning the electrophotographic photosensitive member,
An electrophotographic photoreceptor unit having the electrophotographic photoreceptor and an intermediate transfer belt unit having the intermediate transfer belt are separable, and a connecting means for connecting the electrophotographic photoreceptor unit and the intermediate transfer belt unit is provided. And
The volume resistivity of the intermediate transfer belt at 15 ° C. × 10% (relative humidity) is RL (Ω · cm), the volume resistivity unevenness in one intermediate transfer belt is ΔRL, the average circumference is LL (mm) and the circumference is The difference between the left and right lengths is ΔLL (mm),
The volume resistivity of the intermediate transfer belt at 30 ° C. × 80% (relative humidity) is RH (Ω · cm), the unevenness of the volume resistivity in one intermediate transfer belt is ΔRH, the average circumference is LH (mm) and the circumference is When the left-right difference is ΔLH (mm),
A process cartridge wherein all of the following relational expressions are satisfied.
1 ≦ RL / RH ≦ 150
1 <ΔRL <100 and 1 <ΔRH <100
0.98 ≦ LH / LL ≦ 1.02
0 ≦ ΔLH / LH <0.005 and 0 ≦ ΔLL / LL <0.005 The process cartridge according to claim 1, wherein the electrophotographic photosensitive member is a drum-shaped electrophotographic photosensitive member that is a rigid body having a diameter of 60 mm or less. The process cartridge according to claim 1, wherein the intermediate transfer belt is stretched by at least two rollers. The process cartridge according to claim 1, wherein a thickness of the intermediate transfer belt is between 40 μm and 300 μm, and a width is between 100 mm and 500 mm. Said electrophotographic photoreceptor for carrying a toner image,
Charging means for charging the electrophotographic photoreceptor,
Exposure means for forming an electrostatic latent image on the electrophotographic photosensitive member charged by the charging means,
Developing means for developing an electrostatic latent image of the electrophotographic photosensitive member formed by the exposure means with toner, and forming a toner image on the electrophotographic photosensitive member;
An intermediate transfer belt having a contact portion with the electrophotographic photosensitive member, for secondary-transferring the toner image transferred after the toner image is primarily transferred from the electrophotographic photosensitive member to a transfer material;
Primary transfer means for primary transferring the toner image from the electrophotographic photosensitive member to the intermediate transfer belt at the corresponding contact portion;
In order to clean the intermediate transfer belt by returning the toner on the intermediate transfer belt to the electrophotographic photosensitive member at the corresponding contact portion, a polarity opposite to the polarity of the toner at the time of the primary transfer is applied to the toner on the intermediate transfer belt. Charge applying means for applying a charge of
Having an electrophotographic photosensitive member cleaning means for cleaning the electrophotographic photosensitive member,
A process in which at least the electrophotographic photosensitive member, the intermediate transfer belt, the primary transfer means, the charge applying means, and the electrophotographic photosensitive member cleaning means are integrally supported, and are detachable from an electrophotographic apparatus main body. Having a cartridge,
The process cartridge is separable into an electrophotographic photosensitive member unit having an electrophotographic photosensitive member and an intermediate transfer belt unit having the intermediate transfer belt, and connects the electrophotographic photosensitive member unit with the intermediate transfer belt unit. Having connecting means,
The volume resistivity of the intermediate transfer belt at 15 ° C. × 10% (relative humidity) is RL (Ω · cm), the volume resistivity unevenness in one intermediate transfer belt is ΔRL, the average circumference is LL (mm) and the circumference is The difference between the left and right lengths is ΔLL (mm),
The volume resistivity of the intermediate transfer belt at 30 ° C. × 80% (relative humidity) is RH (Ω · cm), the unevenness of the volume resistivity in one intermediate transfer belt is ΔRH, the average circumference is LH (mm) and the circumference is When the left-right difference is ΔLH (mm),
An electrophotographic apparatus, wherein all of the following relational expressions are satisfied.
1 ≦ RL / RH ≦ 150
1 <ΔRL <100 and 1 <ΔRH <100
0.98 ≦ LH / LL ≦ 1.02
0 ≦ ΔLH / LH <0.005 and 0 ≦ ΔLL / LL <0.005 The electrophotographic apparatus according to claim 5, wherein the electrophotographic photosensitive member is a drum-shaped electrophotographic photosensitive member that is a rigid body having a diameter of 60 mm or less. The electrophotographic apparatus according to claim 5, wherein the intermediate transfer belt is stretched by at least two or more rollers. The electrophotographic apparatus according to claim 5, wherein the intermediate transfer belt has a thickness between 40 μm and 300 μm, and a width between 100 mm and 500 mm. A charging step of charging the electrophotographic photosensitive member,
An exposure step of forming an electrostatic latent image on the electrophotographic photosensitive member charged in the charging step;
Developing the electrostatic latent image of the electrophotographic photosensitive member formed in the exposing step with toner, and forming a toner image on the electrophotographic photosensitive member;
A primary transfer means for primary transferring the image of the toner formed in the developing step from the electrophotographic photosensitive member to an intermediate transfer belt having a contact portion with the electrophotographic photosensitive member,
A secondary transfer step of secondary transferring the toner image primarily transferred in the primary transfer step to a transfer material,
A charge applying step of applying a charge having a polarity opposite to the polarity of the toner at the time of the primary transfer step to the toner on the intermediate transfer belt by a charge applying unit;
An intermediate transfer belt cleaning step of cleaning the intermediate transfer belt by returning the toner on the intermediate transfer belt to the electrophotographic photosensitive member at a corresponding contact portion;
An electrophotographic photoreceptor cleaning step of cleaning the electrophotographic photoreceptor,
A process in which at least the electrophotographic photosensitive member, the intermediate transfer belt, the primary transfer means, the charge applying means, and the electrophotographic photosensitive member cleaning means are integrally supported, and are detachable from an electrophotographic apparatus main body. An image forming method using an electrophotographic apparatus having a cartridge,
The process cartridge is separable into an electrophotographic photosensitive member unit having an electrophotographic photosensitive member and an intermediate transfer belt unit having the intermediate transfer belt, and connects the electrophotographic photosensitive member unit with the intermediate transfer belt unit. Having connecting means,
The volume resistivity of the intermediate transfer belt at 15 ° C. × 10% (relative humidity) is RL (Ω · cm), the volume resistivity unevenness in one intermediate transfer belt is ΔRL, the average circumference is LL (mm) and the circumference is The difference between the left and right lengths is ΔLL (mm),
The volume resistivity of the intermediate transfer belt at 30 ° C. × 80% (relative humidity) is RH (Ω · cm), the unevenness of the volume resistivity in one intermediate transfer belt is ΔRH, the average circumference is LH (mm) and the circumference is When the left-right difference is ΔLH (mm),
An image forming method, wherein all of the following relational expressions are satisfied.
1 ≦ RL / RH ≦ 150
1 <ΔRL <100 and 1 <ΔRH <100
0.98 ≦ LH / LL ≦ 1.02
0 ≦ ΔLH / LH <0.005 and 0 ≦ ΔLL / LL <0.005 The image forming method according to claim 9, wherein the electrophotographic photoconductor is a drum-shaped electrophotographic photoconductor that is a rigid body having a diameter of 60 mm or less. The image forming method according to claim 9, wherein the intermediate transfer belt is stretched by at least two rollers. The image forming method according to claim 9, wherein the thickness of the intermediate transfer belt is between 40 μm and 300 μm, and the width is between 100 mm and 500 mm. An intermediate transfer belt for a process cartridge that is detachable from an electrophotographic apparatus main body,
An electrophotographic photosensitive member for carrying a toner image,
An intermediate transfer belt having a contact portion with the electrophotographic photosensitive member,
Primary transfer means for primary transferring the toner image from the electrophotographic photosensitive member to the intermediate transfer belt at the corresponding contact portion;
In order to clean the intermediate transfer belt by returning the toner on the intermediate transfer belt to the electrophotographic photosensitive member at the corresponding contact portion, a polarity opposite to the polarity of the toner at the time of the primary transfer is applied to the toner on the intermediate transfer belt. Charge applying means for applying a charge of
Integrally supporting electrophotographic photosensitive member cleaning means for cleaning the electrophotographic photosensitive member,
It is separable into an electrophotographic photosensitive member unit having the electrophotographic photosensitive member and an intermediate transfer belt unit having the intermediate transfer belt,
An intermediate transfer belt for a process cartridge having a connecting means for connecting the electrophotographic photosensitive member unit and the intermediate transfer belt unit,
The volume resistivity of the intermediate transfer belt at 15 ° C. × 10% (relative humidity) is RL (Ω · cm), the volume resistivity unevenness in one intermediate transfer belt is ΔRL, the average circumference is LL (mm) and the circumference is The difference between the left and right lengths is ΔLL (mm),
The volume resistivity of the intermediate transfer belt at 30 ° C. × 80% (relative humidity) is RH (Ω · cm), the unevenness of the volume resistivity in one intermediate transfer belt is ΔRH, the average circumference is LH (mm) and the circumference is When the left-right difference is ΔLH (mm),
An intermediate transfer belt, wherein all of the following relational expressions are satisfied.
1 ≦ RL / RH ≦ 150
1 <ΔRL <100 and 1 <ΔRH <100
0.98 ≦ LH / LL ≦ 1.02
0 ≦ ΔLH / LH <0.005 and 0 ≦ ΔLL / LL <0.005 14. The intermediate transfer belt according to claim 13, wherein the electrophotographic photosensitive member is a drum-shaped electrophotographic photosensitive member that is a rigid body having a diameter of 60 mm or less. The intermediate transfer belt according to claim 13, wherein the intermediate transfer belt is stretched by at least two or more rollers. The intermediate transfer belt according to claim 13, wherein a thickness of the intermediate transfer belt is between 40 μm and 300 μm, and a width is between 100 mm and 500 mm.

Images