JP2003295623A - Image forming apparatus, belt-like transfer member, image forming method, and cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that obtains high image quality free of image omission and image density variation and ensures a satisfactory image even in case of transport for a long period of time or an environmental change in a short period of time, and to provide an image forming method, and a belt-like transfer member and a cartridge which are used for the image forming apparatus. <P>SOLUTION: In the electrophotographic image forming apparatus in which a latent image formed on a latent image carrier is developed with developer and the obtained image is transferred to a transfer material using the belt-like transfer member, the belt-like transfer member contains at least a thermoplastic resin and a resistance control agent, water soluble content thereof is 2.5 mass% or less, and volume resistivity is 1×10<SP>6</SP>Ω.cm to 8×10<SP>13</SP>Ω.cm. The image forming method, and the belt-like transfer member and cartridge which are used for the image forming device are also provided. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a laser printer, an image forming method, and a belt-shaped transfer member and a cartridge used for them.

[0002]

2. Description of the Related Art An image forming apparatus using a belt-shaped transfer member such as an intermediate transfer belt and a transfer / conveying belt sequentially transfers a plurality of component color images of full-color image information and multi-color image information in a layered manner to transfer a full-color image and a multi-color image. The present invention is effective as a full-color image forming apparatus or a multi-color image forming apparatus that outputs an image-formed product in which a color image is combined and reproduced, or an image forming apparatus having a full-color image forming function or a multi-color image forming function. Also,
Even in a monochrome image forming apparatus, the transfer / transport belt is effective as a means for improving the printing speed.

For example, in a full-color electrophotographic apparatus having an image forming apparatus using an intermediate transfer belt or the like, a transfer material is pasted or adsorbed on a transfer drum which is a conventional technique,
Compared with a full-color electrophotographic apparatus having an image forming apparatus for transferring an image from a latent image carrier (hereinafter, referred to as a photoconductor), for example, a transfer apparatus described in JP-A-63-301960, a transfer material Since the image can be transferred from the intermediate transfer belt without the need for processing (for example, gripping with a gripper or giving a curvature), the envelope,
A wide variety of transfer materials, from thin paper (40 g / m ² paper) to thick paper (200 g / m ² paper), such as postcards and label paper, regardless of width, width, length, or thickness. It has the advantage that it can be selected from

Further, a method of arranging a plurality of photoconductors according to the number of colors and continuously transferring images of respective colors in one pass to superimpose the colors is effective as a means for greatly improving the printing speed. In this system, both a transfer / transport belt and an intermediate transfer belt can be used.

Further, in the case of the intermediate transfer belt, the degree of freedom in arranging the intermediate transfer belt inside the image forming apparatus is increased as compared with the case where a rigid cylinder such as the intermediate transfer drum is used, and the space of the apparatus main body is effectively utilized. It is possible to reduce the size and cost.

However, these belt-shaped transfer members are required to satisfy various characteristics depending on the purpose of use, and there are many problems to be solved. In recent years, the latent image forming and developing technology of the main body of the electrophotographic apparatus has advanced, and the belt-shaped transfer member is required to have higher and stable performance. Particularly, the adjustment of the resistance value, which is an important characteristic in the intermediate transfer belt and the transfer / conveyance belt, and the equalization thereof are mentioned. In order to adjust the resistance, a means of mixing some kind of resistance control substance into the belt-shaped transfer member is used, but if uniform resistance is considered, it is a conductive filler such as carbon black or conductive metal oxide particles. The resistance unevenness due to the agglomeration and non-uniformity of the particles is likely to occur. In particular, the agglomerates of particles have a great influence on the transfer electric field at the site even if the agglomerates are 50 μm or less, and an image such as spot-like color loss in the range of several times to ten times or more the size of the agglomerates. May cause abnormalities. Further, when the agglomerates are large, dielectric breakdown may occur due to the application of voltage, which may cause serious defects such as smoke generation and belt perforation. Therefore, when using the conductive filler, reduction of the addition amount and improvement of the dispersion means have become problems. On the other hand, a so-called ionic conductive agent such as a surfactant or an antistatic resin has a high uniformity of resistance, but it oozes out on the surface of the belt with the passage of time or in a high temperature and high humidity environment and adheres to surrounding members to cause various May cause problems.

In particular, in the case of a photoconductor-intermediate transfer belt cartridge in which a photoconductor and an intermediate transfer belt are integrated so that replacement can be easily performed in consideration of maintainability, the intermediate transfer belt is set when the main body is installed. Problems tend to occur unlike when doing. This is often due to the fact that the intermediate transfer belt and the photoreceptor are left in various environments for a long time in a state where they are integrated. For example, if the above-mentioned ionic conductive agent oozes out from the intermediate transfer belt and adheres to the photoconductor, the charging potential will drop, or the movement of the charge will be affected, causing a difference in sensitivity characteristics, and a density difference from the surroundings during printing. Results in an abnormal image. The most serious problem is that the material exuding from the intermediate transfer belt causes cracks in the photosensitive layer. Such cracking of the photosensitive layer is remarkable in the thickest layer in the photosensitive layer, and is easily generated in the charge transport layer in the case of the laminated photoreceptor.

It has been known that such a phenomenon is promoted particularly in a high temperature environment, and the humidity tends to be adversely affected as the humidity becomes higher. Therefore, the intermediate transfer belt photoreceptor integrated cartridge needs to be designed in consideration of the influence of temperature and humidity at the distribution stage.

Also, due to the recent expansion of the user base, the environment in which copying machines and printers are used has expanded, and it has become necessary to consider short-term fluctuations in temperature and humidity. It should be noted that image defects due to abrupt changes in temperature and humidity may occur even if the product is designed for use under high temperature and high humidity.

Further, the technology of the image forming apparatus has advanced, and in printers and copiers of the digital developing system, it is possible to develop fine and dense pixels of 600 dpi or more by reducing the exposure spot diameter and increasing the density. In addition to this, high-quality images are being obtained by precise control of the electric field. As a result, even a slight abnormality of the photoconductor or the intermediate transfer belt, which has not been a problem in the past, may affect the image quality, and improvement of this problem is an important issue.

As described above, an image forming apparatus that completely solves various problems in the image forming apparatus using the belt-shaped transfer member has not yet been obtained.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to form an image in which a high image quality without image dropout or density unevenness can be obtained, and a good image can be obtained even if the environment is changed for a long period of time or the environment changes in a short period of time. An object is to provide an apparatus and an image forming method.

Another object of the present invention is to provide a belt-shaped transfer member and a cartridge used in the above image forming apparatus.

[0014]

According to the present invention, an electrophotographic system in which a latent image formed on a latent image carrier is made visible by a developer and the obtained image is transferred to a transfer material by using a belt-shaped transfer member. In the image forming apparatus, the belt-shaped transfer member contains at least a thermoplastic resin and a resistance control agent, the water-soluble component amount is 2.5% by mass or less, and the volume resistivity is 1 ×.
Provided are an image forming apparatus, a belt-shaped transfer member, and an image forming method that are 10 ⁶ Ω · cm to 8 × 10 ¹³ Ω · cm.

Further, according to the present invention, the latent image formed on the latent image carrier is made visible by a developer, and the obtained image is temporarily transferred to a belt-shaped transfer member, and then transferred to a transfer material. In an intermediate transfer belt-latent image carrier integrated cartridge used in an intermediate transfer belt type image forming apparatus having a secondary transfer step, the cartridge retains the developer remaining on the intermediate transfer belt after the secondary transfer during the primary transfer. It has a mechanism that charges it to the opposite polarity and returns it to the latent image carrier simultaneously with the primary transfer from the intermediate transfer belt. The intermediate transfer belt, the latent image carrier and the cleaning mechanism for the latent image carrier are arranged in a unit. The belt-shaped transfer member contains at least a thermoplastic resin and a resistance control agent, has a water-soluble component content of 2.5 mass% or less, and has a volume resistivity of 1 or less. ^{10 6 Ω · cm~8 × 10 13} Ω
An intermediate transfer belt-latent image carrier integrated cartridge of cm is provided.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

In the present invention, a so-called solid electrolyte such as a low molecular weight metal salt or a surfactant as a resistance control agent is dispersed in the resin of the belt substrate, or is called a hydrophilic resin, an antistatic resin or a conductive resin. The method of adjusting the resistance is mainly performed by kneading a low-resistance thermoplastic resin into the main binder. According to this means, carbon black, conductive metal oxides, or the like, which does not cause particle-level aggregation or deviation like conductive fillers such as metal powder, can suppress the occurrence of resistance unevenness and dielectric breakdown. it can. Furthermore, various measures are taken to adjust the resistance value and prevent the conductive agent and the like from seeping out in the environment. Belt resistance is 8 × 10 ¹³ Ω
If it is higher than cm, a high applied voltage is required for transfer, the power source becomes large, and there arise problems such as a decrease in transfer efficiency due to insufficient transfer current. Also, 1 × 10 ⁶ Ω · cm
Even if it is lower, a sufficient transfer voltage is not applied and the transfer performance is deteriorated. Furthermore, the amount of water-soluble components in the belt is 2.5% by mass.
It must be: The water-soluble component is a low-molecular weight component of the antistatic resin or a component in which water-soluble functional groups are concentrated, or is a surfactant or various metal salts that are particularly incompatible with the main binder of the belt. These are the causative substances that exude to the surface of the belt due to long-term storage under high temperature and high humidity and due to rapid humidity changes, adhere to the photoconductor and cause a partial reduction in resistance of the photoconductor. It is preferably 0.8% by mass or less.

Further, in order to downsize the image forming apparatus and the cartridge and reduce the cost, the cleaning mechanism of the intermediate transfer belt charges the secondary transfer residual toner to the opposite polarity and simultaneously returns to the photoreceptor at the time of primary transfer. It is preferable to use a cleaning method. Specifically, a voltage is applied to a charging member such as a cleaning roller which is arranged on the intermediate transfer belt so as to be able to come into contact with and separate from the intermediate transfer belt, so that the secondary transfer residual toner is charged with an opposite polarity to that at the time of primary transfer. It is a means for returning to the photoreceptor by the primary transfer electric field. A blade, a corona charger, or the like may be used as the means for charging the toner to the opposite polarity. 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, cleaning blades and the like are arranged on both the photoconductor and the intermediate transfer belt, and compared to a method in which a waste toner feeding mechanism and a container are installed, a large effect can be obtained in reducing the size and cost of the apparatus body and cartridge. is there.

An example of the embodiment of the present invention will be shown below, but the present invention is not necessarily limited to this.

As the molding method, it is preferable to use a manufacturing method capable of manufacturing a seamless belt, having high manufacturing efficiency, and suppressing costs. As a means for this, there is a method of producing a belt by continuously melt-extruding from an annular die and then cutting it to a required length.

For example, inflation molding is suitable. Inflation molding can extrude multiple sizes with different diameters from one type of die, and has the advantages of reducing capital investment when deploying to multiple models and improving production efficiency. Furthermore, when expanding in a molten state at the time of extrusion, a thick portion is selectively stretched in the circumferential direction to be thin, and therefore, there is an advantage that unevenness in thickness is reduced as compared with normal extrusion molding.

As another manufacturing means, there is a manufacturing method in which a sheet is formed from a T-die, cut into a desired length, the ends are joined, and a belt is formed. With this method, the film thickness is highly uniform, and since a biaxial stretching device can be used, there are many advantages such as the mechanical strength of the film can be improved.

The thickness of the belt-shaped transfer member in the present invention is preferably in the range of 40 μm to 300 μm. If the thickness is less than 40 μm, the molding stability may be poor, the thickness may be uneven, the durability may be insufficient, and the belt may be broken or cracked. On the other hand, if the thickness exceeds 300 μm, the material increases and the cost increases, and the peripheral speed difference between the inner surface and the outer surface of the tension shaft becomes large when incorporated in the main body of the electrophotographic apparatus, and when used as an intermediate transfer belt, the outer surface becomes large. Problems such as image scattering due to the contraction of the are likely to occur. Further, the bending durability is lowered and the rigidity of the belt becomes too high to increase the driving torque, resulting in an increase in the size of the main body and an increase in cost, which may cause the problem.

FIG. 5 shows an example of a belt-shaped transfer member molding apparatus of the present invention. The device basically consists of an extruder, an extrusion die and a gas blowing device.

First, a hopper 1 equipped with an extruder 100 of a molding raw material in which a molding resin, a conductive agent, an additive and the like are premixed in advance based on a desired formulation and then kneaded and dispersed.
Add to 02. Extruder 100 has
The set temperature and the screw configuration of the extruder are selected so that the melt viscosity is such that belt molding can be performed in the subsequent step and the raw materials are uniformly dispersed. The forming raw material is melted and kneaded in the extruder 100 to form a melt, and then enters the annular die 103. The annular die 103 is a gas introduction path 104
Is provided, and air is blown into the center of the annular die 103 from the gas introduction passage 104, so that the die 10
The melt that has passed 3 expands and expands in the radial direction to form the tubular film 110.

As the gas blown at this time, nitrogen, carbon dioxide, argon or the like can be selected in addition to air. The expanded molded body is pulled upward while being cooled by the external cooling ring 105. Usually, in an inflation device, a tube is crushed from the left and right by a stabilizer 106, folded into a sheet, and pinched by a pinch roller 107 so as not to let air inside escape, and a method is taken in at a constant speed. Next, the taken film is cut by the cutting device 108 to obtain a tubular film having a desired size. Next, by covering the cylindrical film with a cylindrical mold made of metal or the like and heating it, it is possible to finely adjust the dimensions and remove the crease formed in the film. After that, a reinforcing member, a rotation guide member, and a position detection member are attached and precision cut as required to manufacture a belt-shaped transfer member.

Further, although the description has been made on the single-layer belt, in the case of two layers, an extruder 101 is additionally arranged as shown in FIG. Extruder 110 to annular die 103
The kneaded and melted product can be fed to expand and expand two layers simultaneously to obtain a two-layer belt.

Of course, when the number of layers is three or more, an extruder may be prepared according to the number of layers. Thus, not only a single layer but also a multilayered belt-shaped transfer member can be molded in a single step in a short time with high dimensional accuracy. The fact that this short-time molding is possible is a good indication that mass production and low-cost production are possible.

The thickness ratio between the annular die and the formed cylindrical film in the present invention is a comparison of the thickness of the formed cylindrical film with respect to the width of the gap (slit) of the annular die. The latter is preferably 1/3 or less, more preferably 1/5 or less.

Similarly, the diameter ratio of the annular die and the formed cylindrical film is a ratio of the outer diameter of the tubular film 110 to the outer shape of the die slit of the annular die 103, expressed as a percentage. % To 400% is preferable.

These represent the stretched state of the material, and when the thickness ratio is larger than 1/3, stretching may be insufficient and problems such as reduction in strength and unevenness in resistance and thickness may occur. On the other hand, when the outer shape is more than 400% or less than 50%, it is excessively stretched, which lowers molding stability and makes it difficult to secure the thickness necessary for the present invention.

Next, the tubular film may be processed using a mold for the purpose of adjusting the surface smoothness and dimensions and removing the creases formed on the film during molding.

Specifically, there is a method of using a set of cylindrical molds made of materials having different thermal expansion coefficients and having different diameters. The coefficient of thermal expansion of the small-diameter cylindrical mold (inner mold) should be higher than that of the large-diameter cylindrical mold (outer mold), and after covering the inner mold with the tubular film formed, the inner mold is covered. Insert into the outer mold so that the tubular film is sandwiched between the inner mold and the outer mold. At this time, it is preferable that the inner mold is designed to be slightly larger than the tubular film, and the film is covered while being stretched. The gap between the molds is calculated by the difference between the heating temperature and the coefficient of thermal expansion between the inner mold and the outer mold and the required pressure. The mold set in the order of the inner mold, the tubular film, and the outer mold is heated to near the softening point temperature of the resin. Upon heating, the inner mold having a large coefficient of thermal expansion expands more than the outer mold, and uniform pressure is applied to the entire surface of the tubular film. At this time, the surface circle of the resin film which has reached the vicinity of the softening point is pressed against the inner surface of the outer mold which has been processed to be smooth, and the smoothness of the surface of the resin film is improved. Then, by cooling and removing the film from the mold, a smooth surface property can be obtained.

The folds can be removed and the dimensions can be finely adjusted by a method in which the film formed by using only the inner mold is covered and heated.

Thereafter, if necessary, a reinforcing member, a guide member, and a position detecting member are attached and precision cutting is performed to manufacture a belt-shaped transfer member.

The thermoplastic resin which is a main material among the molding raw materials used for the belt of the present invention is not particularly limited as long as it satisfies the characteristics of the present invention. For example, an olefin resin such as polyethylene or polypropylene or Polystyrene resin, acrylic resin, polyester resin, polycarbonate, sulfur-containing resin such as polysulfone, polyether sulfone and polyphenylene sulfide, fluorine-containing resin such as polyvinylidene fluoride and polyethylene-tetrafluoroethylene copolymer, polyurethane resin, silicone Resins, ketone resins, polyvinylidene chloride, polyimide resins, polyamide resins, modified polyphenylene oxide resins and the like, and one or more kinds of these various modified resins and copolymers can be used. However, the material is not limited to the above materials.

Next, a resistance control agent is contained in order to adjust the electric resistance value of the belt-shaped transfer member of the present invention. In the case of a low molecular weight, various metal salts, surfactants, ionic conductivity of glycols and the like are used. When the material has a high molecular weight, an antistatic resin containing an ether group, a hydroxyl group or the like in the molecule, a thermoplastic resin having electronic conductivity, or the like can be used. What is needed here is a low molecular weight material that is well compatible with the main thermoplastic resin and can create a molecularly dispersed state, or a material that can be melted and polymer blended at the same time. Materials that are compatible or difficult to melt with the main thermoplastic resin immediately deposit on the belt surface,
It causes a problem. Even if they seem to be blended with thermoplastic antistatic resins at first glance, if the dispersion state is insufficient, the amount of water-soluble components will increase significantly, and the contamination of the photoconductor and other components will be increased under high temperature and high humidity. Cause problems. Therefore, the means for achieving the amount of the water-soluble component in the present invention is not particularly limited, but it is selected by sufficiently considering the respective characteristics of the basic resin material and the resistance adjusting material, and further the dispersion condition of the material. In addition, it is necessary to optimize the temperature, discharge amount, etc. during molding.

Further, a means for positively removing the water-soluble component of the resistance adjusting material is also effective. A polymeric material such as an antistatic resin has a distribution in its composition and molecular weight, and in particular, a component having high water solubility may be mixed therein. Means for removing these water-soluble components include, for example, a method in which the antistatic resin is immersed in water and stirred to remove the water-soluble portion in advance, or a reaction such as a coupling agent when kneading the belt material. There is also a method in which a functional additive is added and reacted with a polar functional group of a low molecular weight component to immobilize it to make it difficult to exude. Also, when a low molecular weight surfactant or various salts are used as a resistance adjuster, selecting one having low water solubility is highly effective for exudation, but even if it is water soluble, it is not compatible with other materials. It is possible to prevent the exudation by the combination of the above, and therefore it is not always impossible to use.

As a means for dispersing the material, an ordinary method can be used, but a twin-screw extruder is preferable because a high shearing force can be obtained.

Next, an example of an electrophotographic apparatus using the belt of the present invention will be shown.

FIG. 1 shows a full-color image forming apparatus (copier or laser beam printer) using an electrophotographic process.

A rotating drum type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) 1 which is repeatedly used as a first image bearing member is rotationally driven at a predetermined peripheral speed (process speed) in an arrow direction.

During the rotation process of the photosensitive drum 1, the primary charger 2
Is uniformly charged to a predetermined polarity and potential. 32
Is a power source for the primary charger, and here alternating current is superimposed on direct current and applied, but only direct current may be applied. Next, an image by an exposing means 3 (not shown, such as a color separation / exposure optical system for a full-color original image, a scanning exposure system by a laser scanner that outputs a laser beam modulated in accordance with a time-series electric digital pixel signal of image information) Upon exposure to light, an electrostatic latent image corresponding to the first color component image (for example, yellow color component image) of the target full-color image is formed.

Next, the electrostatic latent image is developed by the first developing device (yellow developing device 41) with the yellow toner Y which is the first color. At this time, the developing units of the second to fourth developing units (magenta color developing unit 42, cyan color developing unit 43, and black color developing unit 44) are in the operation-off state and do not act on the photosensitive drum 1. The first color yellow toner image is not affected by the second to fourth developing devices.

The intermediate transfer belt 5 is rotationally driven in the direction of the arrow at the same peripheral speed as the photosensitive drum 1.

The above-mentioned first formed and carried on the photosensitive drum 1.
The yellow toner image of a color is intermediately transferred by the electric field formed by the primary transfer bias applied from the primary transfer roller 6 to the intermediate transfer belt 5 while passing through the nip portion between the photosensitive drum 1 and the intermediate transfer belt 5. The primary transfer is sequentially performed on the outer peripheral surface of the belt 5.

The surface of the photosensitive drum 1 on which the transfer of the yellow toner image of the first color corresponding to the intermediate transfer belt 5 is completed is
It is cleaned by the cleaning device 13.

Similarly, a magenta toner image of the second color, a cyan toner image of the third color, and a black toner image of the fourth color are sequentially transferred onto the intermediate transfer belt 5 in an overlapping manner to correspond to the target full-color image. The combined full-color toner image is formed.

The secondary transfer roller 7 corresponds to the secondary transfer counter roller 8 and is supported in parallel to the lower surface of the intermediate transfer belt 5 so as to be separated therefrom.

The primary transfer bias for sequentially superposing and transferring the toner images of the first to fourth colors from the photosensitive drum 1 to the intermediate transfer belt 5 is applied from the bias power source 30 with the polarity (+) opposite to that of the toner. . The applied voltage is +100, for example.
It is in the range of V to 2 kV.

In the primary transfer process of the toner images of the first to third colors from the photosensitive drum 1 to the intermediate transfer belt 5, the secondary transfer roller 7 can be separated from the intermediate transfer belt 5.

The transfer of the synthetic full-color toner image transferred onto the intermediate transfer belt 5 onto the transfer material P which is the second image bearing member is performed while the secondary transfer roller 7 is brought into contact with the intermediate transfer belt 5. Transfer material guide 1 from paper feed roller 11
0, the transfer material P is fed to the contact nip between the intermediate transfer belt 5 and the secondary transfer roller 7 at a predetermined timing, and the secondary transfer bias is applied from the power supply 31 to the secondary transfer roller 7. . By this secondary transfer bias, the synthetic full-color toner image is secondarily transferred from the intermediate transfer belt 5 to the transfer material P which is the second image carrier. The transfer material P that has received the transfer of the toner image is introduced into the fixing device 15 and is heated and fixed.

After the transfer of the image to the transfer material P is completed, the cleaning charging member 9 which is arranged so as to be freely contactable with 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 that has not been transferred to the transfer material P and remains on the intermediate transfer belt 5 is given a charge of the opposite polarity to that at the time of primary transfer. 33 is a bias power supply. Here, alternating current is superimposed on direct current and applied. The transfer residual toner charged to the opposite polarity to that at the time of primary transfer is electrostatically transferred to the photosensitive drum 1 in the nip portion with the photosensitive drum 1 and in the vicinity thereof, thereby cleaning the intermediate transfer member. Since this step can be performed at the same time as the primary transfer, there is no reduction in throughput.

Next, the intermediate transfer belt-photoreceptor integrated cartridge of the present invention will be described. As shown in FIG. 2, the cartridge of the present invention is configured such that at least the intermediate transfer belt 5, the photoconductor 1, the intermediate transfer belt cleaning mechanism 13 and the photoconductor cleaning mechanism 9 are integrated into a unit, and can be easily attached to and detached from the main body. It has become.
The cleaning of the intermediate transfer belt of the present invention is a mechanism necessary for charging the transfer residual toner to the polarity opposite to that of the primary transfer and returning it to the photoconductor at the primary transfer portion as described above. The cleaning roller 9 made of an elastic body is provided. Cleaning of the photoconductor is blade cleaning. A waste toner container is also integrated in this cartridge, and the transfer residual toner of both the intermediate transfer belt and the photoconductor is discarded at the same time when the cartridge is replaced, which contributes to the improvement of maintainability. The intermediate transfer belt is stretched by two rollers 8 and 12 to reduce the number of parts and downsize. Here, 8 is a drive roller and at the same time an opposing roller of the cleaning roller. The tension roller 12 that rotates following the intermediate transfer belt has a mechanism that slides, and is pressed against the intermediate transfer belt in the direction of the arrow to give tension to the intermediate transfer belt. The slide width is about 1-5 mm,
The total pressure of the spring is about 5 to 100N. Further, the photoconductor 1 and the drive roller 8 have a coupling (not shown),
Rotational driving force is transmitted from the main body.

Further, another example of the image forming apparatus is shown in FIGS.
Shown in. 3 and 4 have the same number of photoreceptors 1 as the number of developers required for image formation, and have the advantage of dramatically improving the printing speed of full-color printing.

FIG. 3 shows the case where an intermediate transfer belt is used.
Similar to FIG. 1, the visible image formed on the photoconductor 1 is sequentially transferred to the intermediate transfer belt 5 and superposed on each other, and then a bias having a polarity opposite to that of the toner is applied by the secondary transfer roller 7 to the transfer material P. Are collectively transferred to. The developer remaining on the intermediate transfer belt is removed by the cleaning device 18.

FIG. 4 shows an example of the transfer / conveyance belt system.
The transfer material P is biased by the suction roller 63, and is adsorbed and conveyed by the transfer conveyance belt 16. The images of the respective colors formed on the photoconductor are sequentially transferred to the transfer material P adsorbed on the transfer conveyance belt by the transfer roller 17 by applying a bias having a polarity opposite to that of the toner, and after being superimposed, the fixing device 15 It is heated and fixed.

The methods for measuring various physical properties relating to the present invention are shown below.

<Volume resistance measuring method> The measuring apparatus uses an ultrahigh resistance meter R8340A (manufactured by Advantest) as a resistance meter, and an ultrahigh resistance measuring sample box TR42 (manufactured by Advantest) as the sample box, but the main electrode is The diameter of the guard ring electrode is 25 mm, the inner diameter is 41 mm, and the outer diameter is 49 mm.

The sample is manufactured as follows. First, the belt-shaped transfer member is cut out into a circle having a diameter of 56 mm with a punching machine or a sharp blade. One side of the cut out circular piece is provided with an electrode by a Pt-Pd vapor deposition film on the entire surface, and the other surface is provided with 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 by the Pt-Pd vapor deposition film. Pt
The -Pd vapor deposition film can be obtained by performing vapor deposition operation for 2 minutes with mild sputter E1030 (manufactured by Hitachi Ltd.).
A sample for which the vapor deposition operation has been completed is used as a measurement sample.

The measurement atmosphere is 23 ° C./55% RH, and the measurement sample is left in the same atmosphere for 12 hours or more in advance. Measurement is discharge 10 seconds, charge 30 seconds,
Measure for 30 seconds with an applied voltage of 1 to 1000 V.

The applied voltage is arbitrarily selected from 1 to 1000 V which is a part of the range of the voltage applied to the intermediate transfer member and the transfer member used in the image forming apparatus of the present invention. Depending on the resistance value, thickness, dielectric breakdown strength, etc. of the sample, the applied voltage used in the above range of applied voltage can be changed at any time.

<Measurement Method of Water-Soluble Component> A test piece having a size of 100 mm × 100 mm was cut out from the belt-shaped transfer member to be measured, left standing in an environment of 23 ° C./55% RH for 24 hours, and then weighed to a unit of 0.1 mg. . Next, 500 ml of 60 ° C. ion-exchanged water is put in a glass container, and the measured test piece is put therein so that it is completely immersed. If the test piece is lighter than water, fix it with a glass rod to prevent it from rising. In this state, the test piece is left in a constant temperature bath at 60 ° C. for 48 hours, then pulled up and dried at 100 ° C. for 24 hours.
After that, the sample is allowed to stand for another 24 hours in an environment of 23 ° C./55% RH, the mass is measured again, and the amount of the water-soluble component is calculated by the following formula: (initial mass−mass after immersion in warm water) / initial mass × 10
0 [%]

[0064]

EXAMPLES The present invention will be described in more detail with reference to specific examples. In addition, "part" in an Example means a mass part.

Example 1 <Preparation of Resistance Control Agent> 10 kg of an ether group- and amide group-containing antistatic resin (referred to as antistatic resin 1) in pellet form in a reaction vessel capable of heating and stirring. After adding 30 kg of exchanged water, heating to 50 ° C. and stirring for 4 hours, only ion-exchanged water is drained through a mesh. The pellets remaining in the reaction vessel are replaced with new ion-exchanged water 3
0 Kg is charged and heated to 50 ° C., stirred for 4 hours, and similarly drained. This operation was repeated 3 times to remove the water-soluble component contained in the antistatic resin. This is antistatic resin 2.

As the surfactant, a fluorine-based surfactant having a solubility in water of 1.5% was selected.

[0067]     Polyvinylidene fluoride (PVDF) 100 parts     Antistatic resin 2 12 parts     Fluorine-based surfactant 0.6 parts     Inorganic filler (insulating metal oxide) 30 parts     Epoxy silane coupling agent 0.01 part

The above composition was mixed with a twin-screw extruder at 210 ° C.
Melt and knead to uniformly disperse and mix each material, and the diameter is 2mm.
It was extruded with a certain degree of strands and cut into pellets. This is referred to as a belt molding compound 1.

Next, in the molding apparatus shown in FIG. 5, the molding die 103 was a single-layer annular die having a die slit diameter of 120 mm. The die slit is 0.8
mm. Into the material hopper 102 of this molding apparatus, the fully heated and dried molding compound 1 is charged,
It was melted by heating and extruded into a cylindrical shape from a die at 210 ° C. An external cooling ring 105 is installed around the die to cool the extruded film by blowing air from the surroundings. Air is blown into the extruded tubular film from the air introduction passage 104 to have a diameter of 145 mm.
After being expanded and expanded up to, it was continuously taken up by a take-up device at a constant speed. The thickness was adjusted to 100 μm. 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 that, the film was cut into a length of 300 mm to form the tubular film 1.

The tubular film 1 was subjected to adjustment of size and surface smoothness and removal of folds using a set of cylindrical dies made of metals having different thermal expansion coefficients. Diameter 150 with high coefficient of thermal expansion
While covering the inner film of mm with the tubular film 1 slightly extended,
The inner surface is inserted into a smoothed outer mold and heated at 170 ° C. for 20 minutes. After cooling, the belt was removed from the cylinder, the end portion was precisely cut, and a meandering prevention member was attached to the back surface of the belt end portion to prepare three belt-shaped transfer members 1 having a diameter of 150 mm.

<Evaluation of Physical Properties> 1 of the above belt-shaped transfer member 1
The volume resistivity and the amount of water-soluble components when 100 V was applied to the book were measured by the above-mentioned method. As a result, the volume resistivity was 3 × 10 ¹⁰ Ω · cm, and the amount of the water-soluble component was 0.21% by mass, which were good results.

<Image Evaluation Test A> As image evaluation test A, the remaining belt-shaped transfer member 1 is used as an intermediate transfer belt in FIG.
Built into the full-color laser beam printer. The photoconductor was a multilayer organic photoconductor in which a conductive coat layer, an undercoat layer, a charge generation layer, and a charge transport layer were sequentially provided on an aluminum cylinder. The printing speed of this device is 4 sheets per minute in full color A4 size, and the resolution is 600 dpi. After being left for 24 hours in an environment of 23 ° C./55% RH, a confirmation test of a character image with a printing ratio of 5%, a full solid image, and a halftone image was performed. As a result, no image defect that was considered to be caused by the seepage from the intermediate transfer belt was found, and there were no defects such as image unevenness and color misregistration, which were good results. Next, in order to confirm whether a problem occurs when the environment suddenly changes, immediately after the above image evaluation, this apparatus was moved to an environment of 30 ° C./80% RH, and the same image was confirmed 2 hours later. However, the result was as good as the initial stage.

<Image Evaluation Test B> Further, the remaining one of the belt-shaped transfer member 1 is incorporated as an intermediate transfer belt into the photoreceptor-intermediate transfer belt integrated cartridge shown in FIG. 2, and this cartridge is transferred to the photoreceptor and the intermediate transfer belt. Leave the belt in contact with the belt in the environment of 40 ° C / 95% RH for 30 days, and then leave it in the environment of 23 ° C / 55% RH for 48 hours, then set it in the electrophotographic apparatus of Fig. 1 and display the image. The same image confirmation test as the evaluation A was performed. As a result, no image defect that was considered to be caused by the seepage from the intermediate transfer belt was found, which was a good result. The results are shown in Table 1.

(Example 2) Three belt-shaped transfer members 2 were molded in the same manner as in Example 1 except that the compound 2 for belt molding was changed to the following compounding ratio.

[0075]     100 parts of PVDF     Antistatic resin 1 10 parts     Inorganic filler (insulating metal oxide) 30 parts

Example 1 for this belt-shaped transfer member 2
When evaluated in the same manner as above, the volume resistivity is 2 ×
The content was 10 ¹¹ Ω · cm and the amount of water-soluble components was 1.28% by mass. The result of the image evaluation A was also good as in Example 1, but in the image evaluation test B, there was a slight amount on the halftone image in the initial first print, but a streak-like dark portion was observed. However, the second and subsequent sheets were good images and had no practical problems. The results are shown in Table 1.

(Example 3) Molding compound 3 having the same composition except that the compounding ratio of the antistatic resin 2 in the belt molding compound 1 of Example 1 was changed to 9 parts by weight.
And adjust the diameter to 305 mm by increasing the amount of air blown inside when forming a tubular film.
Three belt-shaped transfer members 3 having a diameter of 310 mm were molded in the same manner as in Example 1 except that the size adjusting mold of mm was used.

The physical property value of the belt-shaped transfer member 3 is 4 × 1.
The content was 0 ¹³ Ω · cm and the amount of water-soluble components was 0.20%. Further, the belt-shaped transfer member 3 was incorporated into the laser beam printer of FIG. 4 as a transfer / transport belt. This device has 6
The printing speed is 00 dpi and the printing speed is 24 sheets per minute in full-color A4 size. The image evaluation test A of Example 1 was performed at 24 minutes per minute.
As a result of carrying out at a speed of one sheet, a good image was obtained, and it was confirmed that there was no problem as a transfer conveyance belt for high speed printing. Next, in the image evaluation test B, after only the transfer and conveyance belt was left under high temperature and high humidity, the image was evaluated by incorporating it in the apparatus main body in an environment of 23 ° C./55% RH, and a good image as in Example 1 was obtained. Was obtained. This result indicates that the low resistance component such as the antistatic agent does not exude to the belt surface. The results are shown in Table 1.

(Comparative Example 1) A comparative belt-shaped transfer member 1 was produced in the same manner as in Example 1 except that the molding compound 3 whose compounding ratio was changed to the following was used.

[0080]     100 parts of PVDF     Surfactant (water-soluble) 5 parts

Using this comparative belt-shaped transfer member 1, the same apparatus and test method as in Example 1 were used for evaluation. The physical properties of the comparative belt-shaped transfer member 1 have a volume resistivity of 1 × 10 ¹⁴
It was as high as Ω · cm, and the amount of water-soluble components was as high as 2.8% by mass. It is presumed that this is because the surfactant did not exist in the belt so much and exuded in the vicinity of the belt surface.

In the subsequent image evaluation test A, 23 ° C. /
In the environment of 55% RH, the solid density was decreased due to the transfer failure. Further, in the environment of 30 ° C./80% RH, the image density was remarkably reduced. Next, in the image evaluation test B, an adhering substance was recognized on the photoconductor corresponding to the portion where the intermediate transfer belt was in contact, and streak-shaped high density was formed on the character image and the halftone image at the circumferential intervals of the photoconductor. The department appeared. After that, the streaks did not disappear even when 100 sheets of image were printed, and it is considered that the photosensitive member was partially deteriorated by the component exuded from the intermediate transfer belt. The results are shown in Table 1.

[0083]

[Table 1]

[0084]

As described above, according to the present invention, it is possible to obtain high image quality without transfer defects and image density unevenness, and to transport for a long period under high temperature and high humidity and to change the environment for a short period. In this case, it is possible to provide an image forming apparatus, an image forming method, a belt-shaped transfer member, and a cartridge that can obtain a good image.

[Brief description of drawings]

FIG. 1 is an intermediate transfer belt and an intermediate transfer belt of the present invention.
FIG. 3 is a diagram showing a schematic configuration of a full-color image forming apparatus using a photoconductor-integrated cartridge.

FIG. 2 is a schematic view of an intermediate transfer belt of the present invention and an intermediate transfer belt-photoreceptor integrated cartridge using the same.

FIG. 3 is a diagram showing a schematic configuration of a full-color image forming apparatus using the intermediate transfer belt of the present invention.

FIG. 4 is a diagram showing a schematic configuration of a full-color image forming apparatus using the transfer / transport belt of the present invention.

FIG. 5 is a diagram showing a schematic configuration of an intermediate transfer belt (single layer) molding apparatus of the present invention.

FIG. 6 is a diagram showing a schematic configuration of an intermediate transfer belt (two-layer) molding apparatus of the present invention.

[Explanation of symbols]

1 photosensitive drum 2 Primary charger 3 exposure light 5 Intermediate transfer belt 6 Primary transfer roller 7 Secondary transfer roller 8 Secondary transfer counter roller 9 Cleaning charging member 10 Transfer material guide 11 Paper feed roller 12 Tension roller 13, 18 Cleaning device 15 Fixing device 16 Transfer conveyor belt 17 Transfer roller 30, 31, 33 Bias power supply 32 Primary charger power supply 41 Yellow color developing device 42 Magenta color developing device 43 Cyan color developing device 44 Black color developing device 100, 101 Single-screw extruder 102 hopper 103 circular die 104 gas introduction path 105 External cooling ring 106 Stabilizer 107 pinch roller 108 cutting device 110 tubular film P transfer material

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ryota Kashihara             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Yuji Sakurai             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Hidekazu Matsuda             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Tsunetoku Ashibe             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Atsushi Tanaka             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Hiroyuki Kobayashi             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H171 FA02 FA10 FA16 FA26 GA24                       GA25 GA38 JA02 JA03 JA08                       JA10 QA02 QA03 QA08 QA24                       QA29 UA03 UA10 UA23                 2H200 FA01 FA18 GA12 GA23 GB12                       GB41 JB07 JB10 JB45 JB46                       JC04 JC15 JC16 MA02 MB01                       MB04

Claims (11)

[Claims] 1. An electrophotographic image forming apparatus in which a latent image formed on a latent image carrier is visualized with a developer, and the obtained image is transferred onto a transfer material by using a belt-shaped transfer member. The pattern transfer member contains at least a thermoplastic resin and a resistance control agent, has a water-soluble component content of 2.5 mass% or less, and has a volume resistivity of 1 × 10 ⁶ Ω · cm to 8 × 10 ¹³ Ω.
An image forming apparatus characterized by being cm. 2. The amount of water-soluble components in the belt-shaped transfer member is 0.
The image forming apparatus according to claim 1, wherein the content is 8% by mass or less. 3. The image forming apparatus according to claim 1, wherein the resistance control agent for the belt-shaped transfer member is selected from the group consisting of a thermoplastic resin, a surfactant and a metal salt. 4. The belt-shaped transfer member is an intermediate transfer belt, and the image forming apparatus temporarily transfers the image developed on the latent image carrier to the intermediate transfer belt and a transfer process from the intermediate transfer belt to a transfer material. And a secondary transfer step for charging the developer remaining on the intermediate transfer belt after the secondary transfer to a polarity opposite to that at the time of the primary transfer and returning it to the latent image carrier from the intermediate transfer belt simultaneously with the primary transfer. The image forming apparatus according to claim 1, further comprising: 5. The intermediate transfer belt-photoreceptor integrated cartridge, wherein the intermediate transfer belt, the latent image carrier, and the cleaning mechanism for the latent image carrier are arranged in an integrated unit, and the intermediate transfer belt-photoreceptor integrated cartridge is configured to be detachable from the main body. The image forming apparatus according to item 4. 6. The belt-shaped member is a transfer conveyance belt,
4. The image on the latent image carrier is transferred to the transfer material by bringing the latent image carrier and the transfer material into contact with each other and applying a voltage while the transfer material is supported and conveyed by the transfer conveyor belt. The image forming apparatus described. 7. A belt used in an electrophotographic image forming apparatus that visualizes a latent image formed on a latent image carrier with a developer and transfers the obtained image to a transfer material using a belt-shaped transfer member. In the belt-shaped transfer member, the belt-shaped transfer member contains at least a thermoplastic resin and a resistance control agent,
A belt-shaped transfer member having a water-soluble component content of 2.5 mass% or less and a volume resistivity of 1 × 10 ⁶ Ω · cm to 8 × 10 ¹³ Ω · cm. 8. A belt-shaped transfer member is an intermediate transfer belt, and a temporary transfer step of temporarily transferring an image developed on a latent image carrier to the intermediate transfer belt and a secondary transfer of transferring from the intermediate transfer belt to a transfer material. And a mechanism for charging the developer remaining on the intermediate transfer belt after the secondary transfer to a polarity opposite to that at the time of the primary transfer and returning it to the latent image carrier from the intermediate transfer belt simultaneously with the primary transfer. , An intermediate transfer belt, a latent image carrier, and a cleaning mechanism for the latent image carrier are disposed in an integrated unit, and are used in an image forming apparatus having an intermediate transfer belt-photoreceptor integrated cartridge structure which is configured to be detachable from the main body. The belt-shaped transfer member according to claim 7. 9. The diameter of the tubular film is controlled by injecting gas into the tubular film obtained by melt extrusion from an annular die to adjust the internal volume, and the extruded tubular film is The belt-shaped transfer member according to claim 7 or 8, which is manufactured by forming a tubular film having a diameter larger than that of the annular die and then cutting the film without using a member that supports the film until it is cooled and solidified. 10. An electrophotographic image forming method in which a latent image formed on a latent image carrier is visualized with a developer, and the obtained image is transferred to a transfer material using a belt-shaped transfer member. The belt-shaped transfer member contains at least a thermoplastic resin and a resistance control agent, has a water-soluble component content of 2.5% by mass or less, and has a volume resistivity of 1 × 10 ⁶ Ω · cm to 8 × 10 ^13.
An image forming method characterized in that it is Ω · cm. 11. A temporary transfer step of exposing a latent image formed on a latent image carrier with a developer, and temporarily transferring the obtained image to a belt-shaped transfer member, and a secondary transfer step of further transferring it to a transfer material. In an intermediate transfer belt-latent image carrier integrated cartridge used in an intermediate transfer belt type image forming apparatus having a cartridge, the cartridge retains the developer remaining on the intermediate transfer belt after the secondary transfer in a polarity opposite to that in the primary transfer. It has a mechanism for charging and returning to the latent image carrier at the same time as the primary transfer from the intermediate transfer belt, and the intermediate transfer belt, the latent image carrier and the cleaning mechanism for the latent image carrier are arranged in an integrated unit. The belt-shaped transfer member is detachably configured, contains at least a thermoplastic resin and a resistance control agent, has a water-soluble component amount of 2.5% by mass or less, and has a volume resistivity of 1 ×.
An intermediate transfer belt-latent image carrier integrated cartridge, which is 10 ⁶ Ω · cm to 8 × 10 ¹³ Ω · cm.