JP2004045973A - Intermediate transfer belt, intermediate transfer belt-electrophotographic photoreceptor integrated cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate transfer belt easy in maintenance, with reduced size and cost, capable of preventing partial abrasion of the electrophotographic photoreceptor and preventing image failure like unevenness of image density in durable use, and to provide an intermediate transfer belt-electrophotographic photoreceptor integrated cartridge and an image forming apparatus. <P>SOLUTION: The intermediate transfer belt, the intermediate transfer belt-electrophotographic photoreceptor integrated cartridge equipped with the intermediate transfer belt, and the image forming apparatus have a guide rib at least at one end of the intermediate transfer belt. A primary transfer means uses a primary transfer roller. The Asker C hardness (Hbr) measured from the image forming face side by superposing the intermediate transfer belt base body on the guide ribs and the Asker C hardness (Hbt)measured from the image forming face side by superposing the intermediate transfer belt base body on the primary transfer roller, are in the following relations:Hbr≤95°, Hbt≤95°, and ¾Hbr-Hbt¾≤45°. <P>COPYRIGHT: (C)2004,JPO

Description

【００６８】
なお、表１中の、転写性、耐久使用後の濃度ムラの各評価の数字１〜５は、大きいほど良好な結果であることを意味し、そのうち１〜３は、本発明の効果が得られていないものであると判断した。
【００６９】
【発明の効果】
以上説明してきたように、本発明によれば、メンテナンスが容易で装置の小型化とコストダウンが図れ、電子写真感光体の偏った磨耗を防止し耐久使用時において画像濃度のムラ等の画像不良を防止することのできる中間転写ベルト、中間転写ベルト−電子写真感光体一体カートリッジ及び画像形成装置を提供することが可能となった。
【図面の簡単な説明】
【図１】本発明の中間転写体−電子写真感光体一体カートリッジを備えた画像形成装置の概略図である。
【図２】本発明の中間転写ベルト−電子写真感光体一体カートリッジの概略図である。
【図３】本発明のガイドリブを有する中間転写ベルトの概略図であり、（ａ）は両方の端部にガイドリブを有する場合、（ｂ）は片方の端部にのみガイドリブを有する場合を示す。
【図４】（ａ）は中間転写ベルト基体とガイドリブを重ね合わせて画像形成面側から測定したアスカーＣ硬度（Ｈｂｒ）、
（ｂ）は中間転写ベルトと一次転写ローラーを重ね合わせて画像形成面側から測定したアスカーＣ硬度（Ｈｂｔ）
の測定方法の概略図である。
【図５】本発明の中間転写ベルトの成形装置の概略構成図である。
【符号の説明】
１　電子写真感光体
２　一次帯電器
３　露光光
５　中間転写ベルト
５ａ　ガイドリブ
６　一次転写ローラー
７　二次転写ローラー
８　二次転写対向ローラー
９　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
１３　クリーニング装置
１５　定着器
３０，３１，３２，３３　電源
４１　イエロー色現像器
４２　マゼンタ色現像器
４３　シアン色現像器
４４　ブラック色現像器
１００，１０１　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
Ｐ　　転写材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an intermediate transfer belt, an intermediate transfer belt-an electrophotographic photosensitive member integrated cartridge, and an image forming apparatus. More specifically, the present invention relates to an intermediate transfer belt having a specific hardness, and an intermediate transfer belt including the intermediate transfer belt-an electrophotographic photosensitive member integrated cartridge. And an image forming apparatus.
[0002]
[Prior art]
An image forming apparatus using an intermediate transfer body is a full-color image forming apparatus that sequentially transfers a plurality of component color images of full-color image information and multi-color image information, and outputs a full-color image or an image formed by combining and reproducing the multi-color image. It is effective as an apparatus or a multicolor image forming apparatus.
[0003]
A full-color image forming apparatus having an intermediate transfer body is a conventional technique in which a second image carrier (transfer material) is stuck or adsorbed on a transfer drum and an image is transferred from an electrophotographic photosensitive member to the second image carrier. As compared with a transfer device such as that described in JP-A-63-301960, an image can be transferred from an intermediate transfer member to a transfer material without any processing or control. (40g / m ² Paper) to thick paper (200g / m ² This has the advantage that a wide variety of second image carriers can be selected irrespective of the width and width of the second image carrier.
[0004]
In addition, by forming the intermediate transfer body in a belt shape, the degree of freedom in disposing the intermediate transfer body inside the image forming apparatus is increased as compared with the case where a rigid cylinder such as an intermediate transfer drum is used, and the apparatus by effectively utilizing space. There is also an advantage that the size and cost of the main body can be reduced.
[0005]
However, the life of the intermediate transfer belt is shorter than that of the main body of the image forming apparatus, and at present, replacement is essential. Further, it is necessary to provide a waste toner container for collecting the toner remaining on the intermediate transfer belt after the secondary transfer, and to perform the processing. In addition, in printers and copiers, many parts such as electrophotographic photosensitive members, developing devices, and developers need to be replaced. Japanese Patent Application Laid-Open No. Hei 8-137181 discloses a method in which these replacement parts are unitized and easily detached from the main body, in which the intermediate transfer belt and the electrophotographic photosensitive member are arranged as independent units so as to be easily detachable from the main body. Has been made.
[0006]
However, this means requires a large number of replacement units, which complicates user operations. Further, since each unit is independently designed and arranged, there arises a problem that the size of the main body is increased and the cost is increased.
[0007]
As a means for solving this problem, means for simultaneously detaching and replacing the intermediate transfer belt and the electrophotographic photosensitive member, which are replacement parts, from the main body as an integrated unit and replacing them is preferable. No. 177329 and JP-A-11-30944.
[0008]
By the way, generally, the intermediate transfer belt is supported by two or more rollers, and is rotationally driven while giving an arbitrary tension. However, the straightness or roundness of the supporting rollers, the parallelism of the axis of each roller, Because there is a slight error or variation in the roundness or the like of the intermediate transfer belt itself, the intermediate transfer belt may meander to the right or left during the rotation driving, and when such an intermediate transfer belt is used, the transfer belt may be meandered. When the above colors are superimposed, the image forming positions of the respective colors are shifted, resulting in a color shift.
[0009]
Therefore, in order to prevent such meandering, a meandering prevention member is provided on the entire inner peripheral surface of the intermediate transfer belt, and a groove is provided in a roller around which the transfer belt is stretched, and the meandering prevention member is engaged with the groove. By rotating the roller while stopping, the transfer belt can run smoothly without meandering, whereby a good image without color shift can be formed.
[0010]
[Problems to be solved by the invention]
The intermediate transfer belt-electrophotographic photosensitive member integrated cartridge has an advantage that it can be easily and easily moved and carried. However, unlike the conventional intermediate transfer belt and the electrophotographic photosensitive member fixed and arranged on the apparatus main body, the conventional intermediate transfer belt and the electrophotographic photosensitive member are used when the integrated cartridge is shipped or when the user removes and transports the integrated cartridge. Frequent and repeated vibrations, mutual friction or sliding that cannot occur. Therefore, the surface of the intermediate transfer belt or the electrophotographic photosensitive member is scratched or scraped.
[0011]
Also, since the intermediate transfer belt and the electrophotographic photosensitive member are always in contact with each other during the durable use of the integrated cartridge, friction and sliding between the intermediate transfer belt and the electrophotographic photosensitive member cause the surface of the electrophotographic photosensitive member to slide. Scratches and shavings occur. Particularly, since the hardness of the image transfer side (drum side) is different between the ribbed portion and the ribless portion, the contact state with the electrophotographic photosensitive member is different in these portions, and the ribbed portion is not so. The degree of occurrence of scratches differs between portions, and uneven drum scraping occurs. As a result, as the endurance is advanced, drum scraping that is deviated in the thrust direction occurs, the drum sensitivity is deviated, and density unevenness occurs in the halftone image.
[0012]
SUMMARY OF THE INVENTION An object of the present invention is to provide an intermediate device capable of easily performing maintenance, reducing the size and cost of an apparatus, preventing uneven wear of an electrophotographic photosensitive member, and preventing image defects such as uneven image density during durable use. An object of the present invention is to provide a transfer belt, an intermediate transfer belt-an electrophotographic photosensitive member integrated cartridge, and an image forming apparatus.
[0013]
[Means for Solving the Problems]
According to the present invention, a process cartridge detachable from an electrophotographic apparatus main body, an electrophotographic photosensitive member for holding a toner image, an intermediate transfer belt having a contact portion with the electrophotographic photosensitive member, A process cartridge for integrally supporting a primary transfer means for primarily transferring the toner image from the electrophotographic photosensitive member to the intermediate transfer belt at the corresponding contact portion, wherein the intermediate transfer belt has a guide rib at at least one end; Having a primary transfer means using a primary transfer roller,
Asker C hardness (Hbr) measured from the image forming surface side when the intermediate transfer belt substrate and the guide rib are superimposed, and Asker C hardness (Hbr) measured from the image forming surface side when the intermediate transfer belt and the primary transfer roller are superimposed. Hbt)
Hbr ≦ 95 °
Hbt ≦ 95 °
| Hbr-Hbt | ≦ 45 °
The present invention provides an intermediate transfer belt-electrophotographic photosensitive member integrated cartridge.
[0014]
Further, according to the present invention, there is provided an image forming apparatus provided with the above-mentioned intermediate transfer belt-electrophotographic photosensitive member integrated cartridge, and an intermediate transfer belt used for the cartridge.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0016]
Intermediate transfer belt-electrophotography that facilitates maintenance, reduces the size and cost of the apparatus, prevents uneven wear of the electrophotographic photoreceptor, and prevents image defects such as uneven image density during durable use. Regarding the photoreceptor-integrated cartridge, the intermediate transfer belt used for the cartridge, and the image forming apparatus using the same, Asker C hardness (Hbr) measured from the image forming surface side when the intermediate transfer belt base and the guide rib are overlapped, It is necessary that the Asker C hardness (Hbt) measured from the image forming surface side by superimposing the intermediate transfer belt and the primary transfer roller satisfies the following relationship;
Hbr ≦ 95 °
Hbt ≦ 95 °
| Hbr-Hbt | ≦ 45 °
[0017]
When the value of Hbr is larger than 95 °, the surface of the electrophotographic photosensitive member is scratched or worn due to contact with the electrophotographic photosensitive member, thereby causing an image defect. Further, since the nip width between the intermediate transfer belt and the electrophotographic photosensitive member is reduced, transferability is deteriorated, which causes image defects. On the other hand, when the value of Hbt is larger than 95 °, the surface of the electrophotographic photosensitive member is scratched or worn due to contact with the electrophotographic photosensitive member, which causes image defects.
[0018]
| Hbr-Hbt | is 45 ° or less, and preferably 35 ° or less. If the value of | Hbr−Hbt | is greater than 45 °, the difference in hardness between the portion with the guide rib and the portion without the guide rib becomes large, and the wear amount of the electrophotographic photosensitive member in the thrust direction during the endurance use is increased. Variations occur. As a result, the sensitivity of the electrophotographic photosensitive member varies in the thrust direction, which causes image defects such as uneven density.
[0019]
In order to make the characteristics of the intermediate transfer belt substrate of the present invention within the above range, the hardness of the intermediate transfer belt substrate, the hardness of the guide rib, the thickness of the intermediate transfer belt substrate, the thickness of the guide rib, and the hardness of the primary transfer roller are combined. This can be achieved.
[0020]
The intermediate transfer belt of the present invention is preferably manufactured using resin, rubber or elastomer. Resins can be broadly classified into thermosetting resins and thermoplastic resins, but in general, thermosetting resins are harder than thermoplastic resins, so electrophotographic photosensitive members are in contact with the electrophotographic photosensitive member. There is a risk of causing scratches on the body. In particular, in the case of a configuration in which the electrophotographic photosensitive member and the intermediate transfer belt are integrated as in the present invention, it is preferable that the intermediate transfer belt is made of a thermoplastic resin. Examples of preferred thermoplastic resins include polyvinylidene fluoride, vinylidene fluoride copolymer, polyester (for example, polyethylene terephthalate and polybutylene terephthalate), polycarbonate, acrylic copolymer, polyolefin (for example, polyethylene and polypropylene), Examples thereof include polyamides and mixtures thereof. Of course, it is not limited to these materials.
[0021]
The thickness of the intermediate transfer belt is preferably from 30 to 300 μm, and particularly preferably from 50 to 200 μm. If the thickness of the belt is less than 30 μm, it is difficult for the intermediate transfer belt to maintain long-term durability, and if it exceeds 300 μm, it is difficult to obtain high belt rigidity and stable running.
[0022]
For the purpose of imparting conductivity to the intermediate transfer belt, various conductive agents such as carbon black such as acetylene black, furnace black and channel black, titanium oxide, potassium titanate, tin oxide, lithium salt and quaternary ammonium salt. May be added.
[0023]
Further, fillers such as talc, mica and calcium carbonate, flame retardants such as magnesium hydroxide and antimony trioxide, and additives such as antioxidants (phenol-based, sulfur-based, etc.) may be added at all. Of course, the additives are not limited to the above substances, and any other additives can be used.
[0024]
As a method for producing the intermediate transfer belt substrate, known methods such as a centrifugal molding method, a continuous melt extrusion molding method, an injection molding method or a blow molding method, and a blown film molding method can be employed. Alternatively, the inflation molding method is preferable because it can be manufactured at low cost. The endless belt molded in this manner may be subjected to an operation such as stretching.
[0025]
Further, the intermediate transfer belt substrate may be composed of a single layer, or may be composed of a plurality of layers. Further, when obtaining an intermediate transfer belt base composed of a plurality of layers, a thermoplastic resin member formed of a plurality of layers in advance may be obtained by extrusion from a multilayer die, or a single layer of a thermoplastic resin member may be obtained. Obtaining a cylindrical film, then, on the front or back surface of this single-layer endless belt, for example, by spraying paint or the like, providing a new layer by dipping, etc. to obtain an intermediate transfer belt base composed of a plurality of layers Is also good.
[0026]
As the guide rib, an elastic body or the like having an appropriate hardness can be used.Specifically, one kind of rubber material such as polyurethane, neoprene rubber, urethane rubber, polyester elastomer, chloroprene rubber, nitrile rubber, butyl rubber and silicone rubber is used. A material obtained by blending two or more types can be used.
[0027]
The shape of the guide rib may be determined according to the conditions of use of the intermediate transfer belt or the like, but it is preferable that the cross section be rectangular or square from the viewpoint of preventing meandering.
[0028]
The thickness of the guide rib is preferably about 0.05 mm to 2.5 mm from the viewpoint of a meandering prevention effect and durability.
[0029]
The width of the guide rib is preferably 2 to 10 mm, more preferably 3 to 8 mm. If the width of the guide rib is less than 2 mm, the strength as a guide cannot be maintained, and the intermediate transfer belt may meander. Further, if the width of the guide rib is larger than 10 mm, if the difference between Hbr and Hbt is large, the portion of the belt surface in contact with the electrophotographic photosensitive member having a different hardness becomes large, and the wear of the electrophotographic photosensitive member during durable use is increased. The amount tends to vary in the thrust direction. As a result, the sensitivity of the electrophotographic photosensitive member varies in the thrust direction, which may cause image defects such as uneven density.
[0030]
As a method for attaching the guide rib to the intermediate transfer belt, a method using a room temperature curing adhesive, a hot melt adhesive, or a method using a pressure-sensitive adhesive (adhesive) can be used. It is preferable to use a pressure-sensitive adhesive with high bonding accuracy.
[0031]
The thickness of the adhesive layer is usually 5 to 500 µm, preferably 20 to 200 µm. That is, when the thickness of the pressure-sensitive adhesive layer is less than 5 μm, the adhesive strength between the guide and the belt tends to be insufficient. On the other hand, when the thickness exceeds 500 μm, the guide is displaced from the pressure-sensitive adhesive layer due to shearing force due to meandering of the guide, and it becomes difficult to control the belt with high accuracy.
[0032]
A belt-like member (not shown) may be provided at the end of the intermediate transfer belt base for the purpose of reinforcing or improving the bonding strength between the intermediate transfer belt base and the guide rib. In addition, various materials can be used as the material of the belt-like member, but PET (polyethylene terephthalate) tape is preferable from the viewpoint of the reinforcing effect of the belt and the ease of handling.
[0033]
Furthermore, various surface treatments such as corona treatment can be applied to the joint surface between the guide rib and the belt main body for the purpose of improving the joint strength between the intermediate transfer belt base and the guide rib.
[0034]
The position where the guide rib is attached is preferably near the end of the intermediate transfer belt from the viewpoint of saving space. As shown in FIGS. 3A and 3B, the number of guide ribs can be two at both ends or only one at one end, but is one from the viewpoint of space saving. Is preferred.
[0035]
For the primary transfer roller, an elastic material having an appropriate hardness can be used, and isoprene rubber, styrene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, butyl rubber, silicone rubber, chloroprene rubber, chlorosulfonated polyethylene, acrylic rubber, hydrin rubber, Rubber materials such as urethane rubber, polysulfide rubber and fluorine rubber, or synthetic rubbers obtained by blending them can be used.
[0036]
In order to make the above-mentioned elastic body conductive, metal oxides such as carbon black, titanium oxide, tin oxide and zinc oxide, SnO 2 ₂ And Sb ₂ O ₃ Solid solution of ZnO and Al ₂ O ₃ Solid solution of In ₂ O ₃ And SnO ₂ It can be carried out by dispersing an appropriate amount of conductive particles composed of metal powders such as copper and silver or particles obtained by coating these particles on the particle surface and making them conductive in an elastic body. It can be adjusted to a desired resistance value.
[0037]
Next, an example of an image forming apparatus using the intermediate transfer belt-electrophotographic photosensitive member integrated cartridge of the present invention is shown in FIG.
[0038]
FIG. 1 shows a color image forming apparatus (copier or laser beam printer) using an electrophotographic process.
[0039]
A rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) 1 repeatedly used as a first image carrier is rotationally driven at a predetermined peripheral speed (process speed) in a direction of an arrow.
[0040]
The photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by the primary charger 2 during the rotation process. The power supply 32 of the primary charger applies an alternating current to a direct current, but may use only a direct current. Next, exposure means (not shown) (a color separation / imaging exposure optical system for a color original image, a scanning exposure system using a laser scanner for outputting a laser beam modulated according to a time-series electric digital pixel signal of image information, etc.) , An electrostatic latent image corresponding to a first color component image (for example, a yellow color component image) of a target color image is formed.
[0041]
Next, the electrostatic latent image is developed by the first developing device (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 turned off and operate on the photosensitive drum 1. The first color yellow toner image is not affected by the second to fourth developing units.
[0042]
The intermediate transfer belt 5 is driven to rotate at a predetermined peripheral speed (process speed) in the direction of the arrow.
[0043]
The first color yellow toner image formed and carried on the photosensitive drum 1 is applied from the primary transfer roller 6 to the intermediate transfer belt 5 while passing through the nip between the photosensitive drum 1 and the intermediate transfer belt 5. The primary transfer is sequentially performed on the outer peripheral surface of the intermediate transfer belt 5 by the electric field formed by the primary transfer bias.
[0044]
After the transfer of the first color yellow toner image corresponding to the intermediate transfer belt 5, the surface of the photosensitive drum 1 is cleaned by the cleaning device 13.
[0045]
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 successively superimposed on the intermediate transfer belt 5 and transferred, and the composite color corresponding to the target color image is transferred. A toner image is formed.
[0046]
A primary transfer bias for sequentially superimposing transfer of the first to fourth color toner images from the photosensitive drum 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 in a range of, for example, +100 V to 3 kV.
[0047]
The secondary transfer roller 7 is supported in parallel with the secondary transfer opposing roller 8 and is disposed on the lower surface of the intermediate transfer belt 5 so as to be separated from the lower surface of the intermediate transfer belt 5. In the primary transfer process of the first to third color toner images, the toner images can be separated from the intermediate transfer belt 5.
[0048]
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 while the secondary transfer roller 7 is in contact with the intermediate transfer belt 5 and the paper feed roller The transfer material P is supplied from the power supply 31 to the secondary transfer roller from the power supply 31 at a predetermined timing through the transfer material guide 10 to a contact nip between the intermediate transfer belt 5 and the secondary transfer roller 7. 7 is applied. 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 having received the transfer of the toner image is introduced into the fixing device 16 and is heated and fixed.
[0049]
After the image transfer to the transfer material P is completed, a cleaning charging member 9 arranged to be detachable from the intermediate transfer belt 5 is brought into contact with the intermediate transfer belt 5, and a bias having a polarity opposite to that of the photosensitive drum 1 is applied. The transfer residual toner remaining on the intermediate transfer belt 5 without being transferred to the P is given a charge having a polarity opposite to that of the primary transfer. The bias power supply 33 applies an alternating current to a direct current. The transfer residual toner charged to a polarity opposite to that of the primary transfer is electrostatically transferred to the photosensitive drum 1 in a nip portion with the photosensitive drum 1 and in the vicinity thereof, thereby cleaning the intermediate transfer member. Since this step can be performed simultaneously with the primary transfer, a decrease in throughput does not occur.
[0050]
Subsequently, the intermediate transfer belt-electrophotographic photosensitive member integrated cartridge of the present invention will be described. As shown in FIG. 2, the cartridge of the present invention comprises at least the intermediate transfer belt 5, the electrophotographic photosensitive member 1, the intermediate transfer belt cleaning means 9, and the electrophotographic photosensitive member cleaning means 13 as an integrated unit. It can be easily attached to and detached from the device body. The cleaning of the intermediate transfer belt of the present invention is a mechanism necessary for charging the transfer residual toner to a polarity opposite to that of the primary transfer as described above, and returning the toner to the electrophotographic photosensitive member at the primary transfer portion. A roller-shaped charge applying means 9 made of a resistance elastic body is provided. Cleaning of the electrophotographic photosensitive member is blade cleaning. The cartridge also includes a waste toner container (not shown), 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, thereby contributing to an improvement in maintainability. .
[0051]
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 a roller opposite to the cleaning roller. The tension roller 12, which 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 about 1 to 5 mm, and the total pressure of the spring is about 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.
[0052]
Each measurement condition was as follows.
[0053]
<Hardness>
The Asker C hardness in the present invention is a hardness measured using an Asker C type spring type rubber hardness tester (manufactured by Kobunshi Keiki Co., Ltd.) based on the Japan Rubber Association Standard SRIS0101, and the sample is measured at 23 ° C. / The specimen was left in an environment of 55% RH for 12 hours or more, and the hardness was measured 30 seconds after the hardness tester was brought into contact with the sample with a force of 10 N. As shown in FIG. 4 (a), Hbr was obtained by installing the intermediate transfer belt on a flat glass plate with the image forming surface facing upward, and measuring the portion of the intermediate transfer belt where the guide ribs were attached. C hardness. Hbt is the Asker C hardness measured by placing the image forming surface of the intermediate transfer belt on the fixed primary transfer roller as shown in FIG. 4B.
[0054]
<Guide rib width>
The width of the guide rib in the present invention is a value obtained by measuring the width of the guide rib attached to the intermediate transfer belt at equal intervals over the entire circumference of four points.
[0055]
<Thickness of intermediate transfer belt>
The film thickness of the intermediate transfer belt of the present invention is a value obtained by cutting out the center of the belt at equal intervals over the entire circumference of eight points, observing the cross section with an optical microscope, measuring, and averaging.
[0056]
【Example】
Hereinafter, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited to these examples. In the examples, “parts” means “parts by mass”.
[0057]
(Example 1)
<Intermediate transfer belt substrate>
70 parts of polyvinylidene fluoride (PVDF)
Polyether-containing antistatic resin 10 parts
15 parts of zinc oxide
5 parts of carbon black
[0058]
These materials were melt-kneaded at 210 ° C. with a biaxial 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.
[0059]
Next, a tubular film was produced using the inflation molding apparatus shown in FIG. As the molding die 103, a single-layer annular die having a die slit diameter of 100 mm was used. 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 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 at 100 μm, the film was cut at a length of 310 mm to form a tubular film 1.
[0060]
This cylindrical film 1 was adjusted in size and surface smoothness and folds were removed using a set of cylindrical molds made of metals having different coefficients of thermal expansion. An aluminum material having a higher coefficient of thermal expansion was used for the inner mold, and a stainless steel having a lower coefficient of thermal expansion than aluminum was used for the outer mold. The outer mold used was buffed on the inner surface and mirror-finished. The dimensional gap between the outer diameter of the inner mold and the inner diameter of the outer mold is 170 μm. The inner film having a high coefficient of thermal expansion is covered with the tubular film 1, and the inner surface of the inner mold is inserted into an outer mold having a smooth inner surface, and heated at 170 ° C. for 20 minutes. After cooling, the end of the seamless belt removed from the cylinder was cut to produce an intermediate transfer belt base 1.
[0061]
A polyurethane foam having a thickness of 2 mm and a width of 4 mm at one end of the inner peripheral surface of the intermediate transfer belt substrate, a rectangular cross-sectional shape, and a skin layer on four sides of the cross-section is a double-sided tape having an acrylic adhesive. By sticking, an intermediate transfer belt having a guide rib was obtained. Further, this was incorporated into an intermediate transfer belt-electrophotographic photosensitive member integrated cartridge having the configuration shown in FIGS. 1 and 2.
[0062]
At this time, Hbr was 75 °, Hbt was 58 °, | Hbr−Hbt | was 17 °, and the film thickness of the intermediate transfer belt was 85 μm.
[0063]
<Image evaluation>
Subsequently, it is installed in the image forming apparatus having the configuration shown in 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. Table 1 shows the results.
[0064]
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.
[0065]
A continuous print test was performed continuously at 5,000 sheets at a speed of 4 sheets per minute, and the images were evaluated in the same manner. As a result, the same good images as those obtained at the initial stage were obtained. -It was confirmed that the electrophotographic photosensitive member integrated cartridge had good performance.
[0066]
(Examples 2 to 5 and Comparative Examples 1 to 4)
Physical properties were measured and an image print test was performed using the same intermediate transfer belt as in Example 1 except that Hbr, Hbt and | Hbr-Hbt | were changed as shown in Table 1. Table 1 shows the results.
[0067]
[Table 1]

[0068]
The numbers 1 to 5 of the evaluations of transferability and density unevenness after durable use in Table 1 indicate that the larger the value, the better the results. Among them, 1 to 3 indicate that the effects of the present invention are obtained. It was determined that it was not done.
[0069]
【The invention's effect】
As described above, according to the present invention, maintenance is easy, the apparatus can be reduced in size and cost can be reduced, uneven wear of the electrophotographic photoreceptor can be prevented, and image defects such as uneven image density during durable use can be prevented. It is possible to provide an intermediate transfer belt, an intermediate transfer belt-electrophotographic photoreceptor integrated cartridge, and an image forming apparatus that can prevent the occurrence of image formation.
[Brief description of the drawings]
FIG. 1 is a schematic view of an image forming apparatus provided with an intermediate transfer member-electrophotographic photosensitive member integrated cartridge of the present invention.
FIG. 2 is a schematic view of an intermediate transfer belt-electrophotographic photosensitive member integrated cartridge of the present invention.
3A and 3B are schematic views of an intermediate transfer belt having guide ribs of the present invention, wherein FIG. 3A shows a case where guide ribs are provided at both ends, and FIG. 3B shows a case where guide ribs are provided only at one end.
FIG. 4 (a) shows Asker C hardness (Hbr) measured from the image forming surface side by superimposing an intermediate transfer belt base and guide ribs,
(B) Asker C hardness (Hbt) measured from the image forming surface side by superimposing the intermediate transfer belt and the primary transfer roller.
It is a schematic diagram of the measuring method of.
FIG. 5 is a schematic configuration diagram of an intermediate transfer belt forming apparatus of the present invention.
[Explanation of symbols]
1. Electrophotographic photoreceptor
2 Primary charger
3 Exposure light
5 Intermediate transfer belt
5a Guide rib
6 Primary transfer roller
7 Secondary transfer roller
8 Secondary transfer facing roller
9 Cleaning roller
10 Transfer material guide
11 Paper feed roller
12 tension roller
13 Cleaning device
15 Fixing device
30, 31, 32, 33 power supply
41 Yellow developing unit
42 Magenta color developing unit
43 Cyan developing unit
44 Black developer
100,101 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
P transfer material

Claims (12)

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,
A process cartridge that integrally supports a primary transfer unit for primary-transferring the toner image from the electrophotographic photosensitive member to the intermediate transfer belt at the corresponding contact portion;
The intermediate transfer belt has a guide rib on at least one end,
The primary transfer means uses a primary transfer roller,
Asker C hardness (Hbr) measured from the image forming surface side by superimposing the intermediate transfer belt base and the guide rib;
The Asker C hardness (Hbt) measured from the image forming surface side by superposing the intermediate transfer belt and the primary transfer roller is Hbr ≦ 95 °.
Hbt ≦ 95 °
| Hbr-Hbt | ≦ 45 °
An intermediate transfer belt and an electrophotographic photosensitive member integrated cartridge. 2. The cartridge according to claim 1, wherein the intermediate transfer belt has a thickness of 30 to 300 [mu] m. The intermediate transfer belt-electrophotographic photosensitive member integrated cartridge according to claim 1 or 2, wherein the width of the guide rib in the intermediate transfer belt is 2 to 10 mm. The intermediate transfer belt-electrophotographic photosensitive member integrated cartridge according to any one of claims 1 to 3, wherein the intermediate transfer belt has a guide rib only at one end. An electrophotographic photosensitive member for carrying a toner image,
An intermediate transfer belt having a contact portion with the electrophotographic photosensitive member,
An image using a process cartridge detachably attached to the main body of the electrophotographic apparatus, integrally supporting a primary transfer means for primarily transferring the toner image from the electrophotographic photosensitive member to the intermediate transfer belt at the corresponding contact portion. In the forming device,
The intermediate transfer belt used in the process cartridge has a guide rib on at least one end,
The primary transfer means uses a primary transfer roller,
Asker C hardness (Hbr) measured from the image forming surface side by superimposing the intermediate transfer belt base and the guide rib;
The Asker C hardness (Hbt) measured from the image forming surface side by superimposing the intermediate transfer belt and the primary transfer roller is Hbr ≦ 95 °.
Hbt ≦ 95 °
| Hbr-Hbt | ≦ 45 °
An image forming apparatus, comprising: The image forming apparatus according to claim 5, wherein the intermediate transfer belt has a thickness of 30 to 300 μm. The image forming apparatus according to claim 5, wherein a width of the guide rib in the intermediate transfer belt is 2 to 10 mm. The image forming apparatus according to claim 5, wherein the intermediate transfer belt has a guide rib only at one end. An intermediate transfer belt used for 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,
An intermediate transfer belt used in a process cartridge that integrally supports a primary transfer unit for primary-transferring the toner image from the electrophotographic photosensitive member to the intermediate transfer belt at the corresponding contact portion;
The intermediate transfer belt has a guide rib on at least one end,
The primary transfer means uses a primary transfer roller,
Asker C hardness (Hbr) measured from the image forming surface side by superimposing the intermediate transfer belt base and the guide rib;
The Asker C hardness (Hbt) measured from the image forming surface side by superimposing the intermediate transfer belt and the primary transfer roller is Hbr ≦ 95 °.
Hbt ≦ 95 °
| Hbr-Hbt | ≦ 45 °
An intermediate transfer belt for use in an electrophotographic photosensitive member integrated cartridge. The cartridge according to claim 9, wherein the intermediate transfer belt has a thickness of 30 to 300 m. The intermediate transfer belt according to claim 9, wherein the width of the guide rib in the intermediate transfer belt is 2 to 10 mm. The intermediate transfer belt according to any one of claims 9 to 11, wherein the intermediate transfer belt has a guide rib at only one end.

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