JP2003241569A - Image forming apparatus and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and an image forming method which prevent image defects such as omission and character dust by improving the transferability of toner used in an image forming system using an intermediate transfer body. <P>SOLUTION: The image forming apparatus having a transfer means which transfers a toner image formed on an electrophotographic photoreceptor is provided with an agent application means which applies a surface energy decreasing agent to the surface of the photoreceptor. The moisture content of the surface energy decreasing agent is 5.0 mass% or less. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and an image forming method used in copying machines, printers, facsimiles and the like.

[0002]

2. Description of the Related Art Conventionally, as a method for transferring a toner image on an electrophotographic photosensitive member (hereinafter, also simply referred to as a photosensitive member) to a recording material for a final image, a toner image formed on the electrophotographic photosensitive member is recorded. A method of directly transferring to a material is known. on the other hand,
An image forming method using an intermediate transfer member is known, and this method includes another transfer step in the step of transferring the toner image from the electrophotographic photosensitive member to the recording material, and the intermediate transfer from the electrophotographic photosensitive member is performed. After the primary transfer to the body, the primary transfer image of the intermediate transfer body is secondarily transferred to the recording material to obtain a final image. Among them, the intermediate transfer method is adopted as a so-called overlapping transfer method of toner images of respective colors in a so-called full-color image forming apparatus, which reproduces a color-separated original image by subtractive color mixing with toners such as black, cyan, magenta, and yellow. It is often done.

However, in any of the above methods, when a large number of copies or prints are made, toner filming occurs on the electrophotographic photosensitive member or the intermediate transfer member, or the surface of the electrophotographic photosensitive member or the intermediate transfer member occurs. The energy increases,
The adhesive force with the toner is increased, the transferability of the toner from the electrophotographic photosensitive member to the recording material or the intermediate transfer member to the recording material is deteriorated, and an image defect is likely to occur in the final image. Particularly in an image forming method using an intermediate transfer member, a transfer process of a primary transfer unit for primary transfer of a toner image from an electrophotographic photosensitive member to an intermediate transfer member and a secondary transfer for transferring a toner image from the intermediate transfer member to a recording material. Since it has two transfer steps, that is, the transfer step of the device, the decrease in transferability significantly deteriorates the quality of the final image.

That is, when the transferability of the toner is lowered in the image forming method using the intermediate transfer member, so-called "middle void" or "character dust", in which a part of the toner image is not transferred, is likely to occur.

In order to improve transferability, prevent toner filming, or improve cleaning deficiency that causes the "blank area" and "character dust", fine particles are contained in the surface layer of the electrophotographic photosensitive member. , To make the surface uneven, reduce the adhesion of toner on the surface of the photoconductor, improve transferability,
Techniques such as reducing the frictional force with the blade have been studied. For example, JP-A-5-181291 reports that a photosensitive layer contains fine particles of alkylsilsesquioxane resin. However, the alkylsilsesquioxane resin fine particles have a hygroscopic property, and in a high humidity environment, the wettability of the surface of the photoconductor, that is, the surface energy becomes large, and the transfer property is likely to deteriorate. On the other hand, JP-A-63-56658 reports an electrophotographic photosensitive member containing a fluororesin powder in order to reduce the surface energy of the photosensitive member surface. However, the fluororesin powder has a problem that sufficient surface strength cannot be obtained and streak failure due to scratches on the surface of the photoconductor is likely to occur.

On the other hand, in order to improve the transferability of the intermediate transfer member, a technique of supplying a solid lubricant to the intermediate transfer member to reduce the surface energy of the intermediate transfer member has been disclosed. For example, JP-A-6-337598 and JP-A-6-332.
324 and JP-A-7-271142. However, it is still insufficient to improve the total transferability of an image forming system using an intermediate transfer member having two transfer steps, only by controlling the surface of the intermediate transfer member, especially at a high temperature. It has been found that further improvement is required for high humidity and long-term formation of copy images.

That is, in the image forming method using the intermediate transfer member, the surface energies of both the electrophotographic photosensitive member and the intermediate transfer member are lowered in a well-balanced manner to improve the total transferability of both the primary transfer and the secondary transfer. Have been found necessary.

[0008]

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art as described above, improves the transferability of toner in an image forming system using an intermediate transfer member, and causes voids and character dust. It is an object of the present invention to provide an image forming apparatus and an image forming method which do not cause the image defect of 1.

[0009]

The object of the present invention is achieved by having the following constitution.

1. An image forming apparatus having a transfer means for transferring a toner image formed on an electrophotographic photosensitive member to a recording material, having an agent applying means for applying a surface energy lowering agent to the surface of the electrophotographic photosensitive member. An image forming apparatus, wherein the water content of the energy lowering agent is 5.0% by mass or less.

2. Ten-point surface roughness R of the electrophotographic photosensitive member
2. The image forming apparatus described in the item 1, wherein z is 0.05 to 4.0 μm.

3. In an image forming apparatus provided with a primary transfer means for transferring a toner image formed on an electrophotographic photosensitive member to an intermediate transfer body, and a secondary transfer means for transferring the toner image transferred on the intermediate transfer body to a recording material. An image forming apparatus comprising: an agent application unit for applying a surface energy reducing agent to the surface of the electrophotographic photosensitive member, wherein the water content of the surface energy reducing agent is 5.0% by mass or less.

4. Ten-point surface roughness R of the electrophotographic photosensitive member
4. The image forming apparatus as described in 3 above, wherein z is 0.05 to 4.0 μm.

5. 5. The image forming apparatus according to any one of 1 to 4 above, wherein the surface energy lowering agent is a fatty acid metal salt.

6. 6. The image forming apparatus according to 5, wherein the fatty acid metal salt is zinc stearate.

7. 5. The image forming apparatus according to any one of 1 to 4 above, wherein the surface energy lowering agent is a fluorine-based resin containing a fluorine atom.

8. 8. The image forming apparatus as described in any one of 1 to 7 above, wherein the surface layer of the electrophotographic photosensitive member contains fine particles having a number average particle diameter of 5 nm to 8 μm.

9. 9. An image forming method, wherein an electrophotographic image is formed using the image forming apparatus described in any one of 1 to 8 above.

That is, by adopting the above-mentioned structure of the present invention, it is possible to prevent the occurrence of voids, character dust, and deterioration of sharpness,
A good electrophotographic image can be formed with an image forming apparatus using an intermediate transfer member.

The present invention will be described in detail below.
FIG. 1 is a sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention.

This color image forming apparatus is called a tandem type color image forming apparatus and comprises a plurality of sets of image forming units 10Y, 10M, 10C and 10K, an endless belt-shaped intermediate transfer body unit 7, and a sheet feeding / conveying unit. It comprises a means 21 and a fixing means 24. In the upper part of the main body A of the image forming apparatus,
A document image reading device SC is arranged.

Image forming unit 1 for forming a yellow image
0Y is a drum-shaped photoconductor 1Y as a first image carrier.
A charging means 2Y, an exposing means 3Y, a developing means 4Y, a primary transfer roller 5Y as a primary transfer means,
It has a cleaning means 6Y. The image forming unit 10M that forms a magenta image includes a drum-shaped photoreceptor 1M as a first image carrier, a charging unit 2M, an exposing unit 3M, a developing unit 4M, and a primary transfer roller 5 as a primary transfer unit.
M, and a cleaning means 6M. The image forming unit 10C that forms a cyan image includes a drum-shaped photoreceptor 1C as a first image carrier, a charging unit 2C, an exposing unit 3C, and
Developing means 4C, primary transfer roller 5 as primary transfer means
C, and a cleaning means 6C. The image forming unit 10K that forms a black image includes a drum-shaped photoreceptor 1K as a first image carrier, a charging unit 2K, an exposing unit 3K, a developing unit 4K, a primary transfer roller 5K as a primary transfer unit, and a cleaning unit. Have 6K.

The endless belt-shaped intermediate transfer member 70 is a semi-conductive endless belt-shaped second image carrier, which is wound around a plurality of rollers and is rotatably supported, as an endless belt-shaped intermediate transfer member 70. Have.

Image forming units 10Y, 10M, 10C, 10
The images of the respective colors formed by K are sequentially transferred onto the rotating endless belt-shaped intermediate transfer member 70 by the primary transfer rollers 5Y, 5M, 5C, and 5K as the primary transfer means, and the combined color image is obtained. It is formed. The paper P as a recording medium accommodated in the paper feeding cassette 20 is fed by the paper feeding means 21.
Is fed by a plurality of intermediate rollers 22A, 22B, 2
After passing through the 2C and 22D and the registration roller 23, it is conveyed to a secondary transfer roller 5A as a secondary transfer means, and is secondary-transferred onto the paper P to collectively transfer color images. The paper P on which the color image has been transferred is subjected to fixing processing by the fixing means 24, is sandwiched by the paper ejection rollers 25, and is ejected outside the apparatus to the paper ejection tray 26.
Placed on top.

On the other hand, after the color image is transferred onto the paper P by the secondary transfer roller 5A as the secondary transfer means, the paper P
The residual toner is removed by the cleaning unit 6A from the endless belt-shaped intermediate transfer body 70 whose curvature is separated.

During the image forming process, the primary transfer roller 5K is constantly in pressure contact with the photoconductor 1K. Other primary transfer roller 5
Y, 5M and 5C are pressed against the corresponding photoconductors 1Y, 1M and 1C only when forming a color image.

The secondary transfer roller 5A is brought into pressure contact with the endless belt-shaped intermediate transfer member 70 only when the sheet P passes therethrough and the secondary transfer is performed.

Further, the housing 8 can be pulled out from the main body A of the apparatus through the support rails 82L and 82R.

The housing 8 is composed of the image forming units 10Y, 10M, 1
0C, 10K and an endless belt-shaped intermediate transfer body unit 7.

Image forming units 10Y, 10M, 10C, 10
The Ks are arranged in a vertical column. Photoconductor 1Y, 1
An endless belt-shaped intermediate transfer body unit 7 is arranged on the left side of M, 1C and 1K in the drawing. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 rotatable around rollers 71, 72, 73 and 74, primary transfer rollers 5Y, 5M, 5C and 5K, and a cleaning unit 6A. Consists of.

FIG. 2 shows an example of cleaning means for the intermediate transfer member. The cleaning means 6A for the intermediate transfer member is composed of a blade 61 attached to a bracket 62 that is rotatably controlled around a support shaft 63 as shown in FIG. 2, and by changing the spring load or weight load, the roller The pressing force of the blade on 71 can be adjusted.

When the housing 8 is pulled out, the image forming sections 10Y, 10M, 10C and 10K and the endless belt-shaped intermediate transfer body unit 7 are integrally pulled out from the main body A.

The support rail 82L on the left side of the casing 8 in the drawing is
It is arranged on the left side of the endless belt-shaped intermediate transfer body 70 in the space above the fixing means 24. The support rail 82R on the right side of the casing 8 in the figure is disposed near the lowermost developing unit 4K. The support rail 82R includes the developing means 4Y, 4
The M, 4C and 4K are arranged at positions where they do not interfere with the operation of attaching and detaching the M, 4C and 4K.

The right side of the photoconductors 1Y, 1M, 1C and 1K of the casing 8 is surrounded by developing means 4Y, 4M, 4C and 4K, and the lower side of the figure is charging means 2Y, 2M, 2C and 2K.
And the cleaning means 6Y, 6M, 6C, 6K and the like, and the left side of the drawing is surrounded by an endless belt-shaped intermediate transfer member 70.

Among them, the photoconductor, the cleaning unit, the charging unit, etc. form one photoconductor unit, and the developing unit, the toner replenishing device, etc. form one developing unit.

FIG. 3 is a layout diagram showing the positional relationship among the photosensitive member, the endless belt-shaped intermediate transfer member, and the primary transfer roller. The primary transfer rollers 5Y, 5M, 5C, and 5K are used as intermediate transfer members as an intermediate transfer member.
Although pressing is applied to Y, 1M, 1C, and 1K, as shown in the layout diagram of FIG. 3, the endless belt-shaped intermediate transfer member 70 as an intermediate transfer member and the photoconductors 1Y, 1M, 1C, and 1 when not pressed.
The primary transfer rollers 5Y, 5M, 5C, and 5K are arranged on the downstream side of the contact point with K in the rotation direction of the photoconductors.
Press to M, 1C, 1K. At this time, the endless belt-shaped intermediate transfer member 70 as an intermediate transfer member is formed on each of the photoconductors 1Y, 1M,
The primary transfer rollers 5Y, 5M, 5C, and 5K are arranged on the most downstream side of the contact area between the photosensitive member and the endless belt-shaped intermediate transfer member 70 by being bent along the outer periphery of 1C and 1K.

FIG. 4 is a layout diagram showing the positional relationship among the backup roller, the endless belt-shaped intermediate transfer member and the secondary transfer roller. As shown in the layout diagram of FIG. 4, the secondary transfer roller 5A is located at the center of contact between the backup roller 74 and the endless belt-shaped intermediate transfer body 70 as an intermediate transfer body when not pressed by the secondary transfer roller 5A. Backup roller 7
It is desirable to be arranged on the upstream side in the rotation direction of No. 4.

As the intermediate transfer member, a polymer film made of polyimide, polycarbonate, PVdF or the like, or a synthetic rubber such as silicone rubber or fluororubber which is made conductive by adding a conductive filler such as carbon black, is used.
Either a drum shape or a belt shape may be used, but a belt shape is preferable from the viewpoint of the degree of freedom in device design.

The surface of the intermediate transfer member is preferably roughened appropriately. Ten-point surface roughness R of intermediate transfer body
By setting z to 0.5 to 2 μm, the surface energy lowering agent supplied to the photoconductor is taken into the surface of the intermediate transfer member, the toner adhesion force on the intermediate transfer member is reduced, and It becomes easy to improve the transfer rate of the secondary transfer of toner. In this case, the effect tends to be greater when the ten-point surface roughness Rz of the intermediate transfer member is larger than the ten-point surface roughness Rz of the photosensitive member.

The present invention is characterized by having an agent application means for supplying a surface energy lowering agent to the surface of the electrophotographic photosensitive member. The agent applying means can be installed at an appropriate position around the electrophotographic photoreceptor, but in order to effectively use the installation space, a part of the charging means, the developing means and the cleaning means shown in FIG. You may install it. Hereinafter, an example in which the agent applying unit is used in combination with the cleaning unit will be described.

FIG. 5 is a block diagram of the cleaning means installed on the photoreceptor of the present invention. The cleaning means is shown in FIG.
6Y, 6M, 6C, 6K and the like are used as cleaning means. The cleaning blade 66A of FIG. 5 is attached to the support member 66B. A rubber elastic body is used as the material of the cleaning blade, and urethane rubber, silicon rubber, fluororubber, chloropyrene rubber, butadiene rubber, and the like are known as the material. Among these, urethane rubber is the other material. It is particularly preferable in that it has excellent wear characteristics as compared with rubber.

On the other hand, the supporting member 66B is composed of a plate-shaped metal member or plastic member. As the metal member, a stainless steel plate, an aluminum plate, a vibration control steel plate, or the like is preferable.

In the present invention, it is preferable that the tip of the cleaning blade, which is brought into pressure contact with the surface of the photoconductor, is brought into pressure contact with a load applied in a direction (counter direction) opposite to the rotation direction of the photoconductor. As shown in FIG. 5, it is preferable that the tip portion of the cleaning blade forms a pressure contact surface when pressure-contacting the photoconductor.

Preferable values of the contact load P and the contact angle θ of the cleaning blade on the photosensitive member are P = 5 to 40 N
/ M, θ = 5 to 35 °.

The contact load P is the cleaning blade 66A.
Is a vector value in the normal direction of the pressure contact force P ′ when the contact is made to the photosensitive drum 1.

The contact angle θ represents the angle between the tangent line X at the contact point A of the photosensitive member and the blade before deformation (shown by the dotted line in the drawing). 66E is a rotating shaft that allows the support member to rotate, and 66G is a load spring.

The free length L of the cleaning blade
Represents the length from the position of the end B of the support member 66B to the tip point of the blade before deformation as shown in FIG. A preferable value of the free length is L = 6 to 15 mm. The thickness t of the cleaning blade is preferably 0.5 to 10 mm.
Here, the thickness of the cleaning blade of the present invention refers to FIG.
Shows the direction perpendicular to the adhesive surface of the support member 66B.

As the cleaning means in FIG. 5, a brush roll 66C which also serves as an agent applying means is used. The brush roll has a function of removing the toner adhering to the photoconductor 1, a function of collecting the toner removed by the cleaning blade 66A, and a function as an agent applying means for supplying the surface energy lowering agent to the photoconductor. That is, the brush roll comes into contact with the photoconductor 1, and in the contact portion, the traveling direction rotates in the same direction as the photoconductor to remove the toner and paper dust on the photoconductor and the toner removed by the cleaning blade 66A. Are transported and collected by the transport screw 66J. A flicker 66I as a removing means is brought into contact with the brush roll 66C along the path between them to remove the removed substances such as toner transferred from the photoconductor 1 to the brush roll 66C. Further, the toner attached to the flicker is removed by the scraper 66D, and the toner is conveyed by the screw 66J.
To collect. The collected toner is taken out as waste, or is conveyed to a developing device through a recycling pipe (not shown) for toner recycling and is reused. As a material for the flicker 66I, a metal tube such as stainless steel or aluminum is preferably used. On the other hand, as the scraper 66D, an elastic plate such as a phosphor bronze plate, a polyethylene terephthalate plate, and a polycarbonate plate is used, and it is preferable that the tip end of the scraper 66D is brought into contact with the scraper 66D by a counter method that forms an acute angle with respect to the rotation direction of the flicker.

Further, the surface energy lowering agent (solid material such as zinc stearate) 66K has a spring load of 6 on the brush roll.
It is pressed and attached by 6S, and while the brush rotates, it rubs against the surface energy lowering agent and supplies the surface energy lowering agent to the surface of the photoreceptor.

A conductive or semiconductive brush roll is used as the brush roll 66C.

Any material can be used as the brush constituting material of the brush roll used in the present invention, but it is preferable to use a fiber-forming polymer which is hydrophobic and has a high dielectric constant. Examples of such a high molecular polymer include rayon, nylon, polycarbonate, polyester, methacrylic acid resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polypropylene, polystyrene, polyvinyl acetate, styrene-butadiene copolymer, vinylidene chloride. -Acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol formaldehyde resin, styrene-alkyd resin, polyvinyl acetal (for example polyvinyl. Butyral) and the like. These binder resins can be used alone or as a mixture of two or more kinds. Particularly preferably rayon,
Nylon, polyester, acrylic resin, polypropylene.

As the brush, a conductive or anti-conductive brush is used, and a brush containing a low resistance substance such as carbon contained in its constituent material and adjusted to an arbitrary specific resistance can be used.

The specific resistance of the bristles of the brush roll is 10 cm in length at room temperature and normal humidity (temperature 26 ° C., relative humidity 50%).
It is preferably in the range of 10 ¹ Ωcm to 10 ⁶ Ωcm when measured with a voltage of 500 V applied to both ends of one of the bristles.

That is, it is preferable to use conductive or semi-conductive brush bristles having a specific resistance of 10 ¹ Ωcm to 10 ⁶ Ωcm for a core material such as stainless steel for the brush roll. 10 ¹ Ω
When the specific resistance is lower than cm, banding due to discharge is likely to occur. On the other hand, if it is higher than 10 ⁶ Ωcm, the potential difference from the photoconductor becomes low, and cleaning failure tends to occur.

The thickness of one brush bristle used for the brush roll is preferably 5 to 20 denier. If it is less than 5 denier, there is no sufficient rubbing force to remove the deposits on the surface. If it is larger than 20 denier, the brush becomes rigid, which damages the surface of the photoconductor and promotes wear.
It shortens the life of the photoconductor.

The term "denier" as used herein is a numerical value obtained by measuring the mass of brush bristles (fibers) constituting the brush having a length of 9000 m in g (gram) unit.

The brush bristle density of the brush is 4.5 × 1.
0 is a ^{2 / cm 2 ~2.0 × 10 4} / cm 2 ( brush hairs per square centimeter). If it is less than 4.5 × 10 ² / cm ² , the rigidity is low, the rubbing force is weak, and the rubbing is uneven, so that the deposits cannot be removed uniformly. 2.0
If it is greater than × 10 ⁴ / cm ² , the image becomes stiff and the rubbing force becomes strong, so that the photoconductor is abraded, and a defective image such as black streaks due to fog or scratches due to a decrease in sensitivity occurs.

The amount of bite of the brush roll used in the present invention with respect to the photosensitive member is preferably set to 0.4 to 1.5 mm. This bite amount means the load applied to the brush generated by the relative movement of the photosensitive drum and the brush roll. Seen from the photosensitive drum, this load is
Corresponding to the rubbing force received from the brush, defining the range means that the photoreceptor needs to be rubbed with an appropriate force.

The bite amount means the length of bite into the inside of the brush when it is assumed that the brush bristles do not bend on the surface of the photoconductor but linearly enter the inside when the brush is brought into contact with the photoconductor.

In the case of the photoconductor to which the surface energy lowering agent has been supplied, the frictional force of the brush on the photoconductor surface is small. Therefore, if the bite amount is less than 0.4 mm, filming of the toner or paper dust on the photoconductor surface is performed. Cannot be suppressed, and defects such as unevenness occur on the image. On the other hand, 1.5
If it is larger than 10 mm, the abrasion of the surface of the photoconductor by the brush is too large, resulting in a large amount of wear of the photoconductor, causing fog due to a decrease in sensitivity or scratches on the photoconductor surface, resulting in streaks on the image. It is a problem because it may break down.

As the core material of the roll portion used in the brush roll of the present invention, metal such as stainless steel and aluminum, paper, plastic and the like are mainly used, but the core material is not limited thereto.

The brush roll used in the present invention preferably has a structure in which a brush is installed on the surface of a cylindrical core material with an adhesive layer interposed therebetween.

The brush roll is preferably rotated so that its abutting portion moves in the same direction as the surface of the photosensitive member.
If the contact portion moves in the opposite direction, when excess toner is present on the surface of the photoconductor, the toner removed by the brush roll may spill and stain the recording paper or the device.

As described above, the photoconductor and the brush roll are
When moving in the same direction, the surface velocity ratio of the two is 1: 1.
It is preferably a value within the range of 1 to 1: 2. If the rotation speed of the brush roll is slower than that of the photoconductor, the toner removal ability of the brush roll is reduced, and cleaning failure is likely to occur.If it is faster than the photoconductor, the toner removal ability becomes excessive and blade bounding or curling occurs. Easier to do.

In the present invention, in the image forming apparatus having the above-mentioned intermediate transfer member, in order to apply the surface energy lowering agent having a water content of 5.0% by mass or less to the surface of the electrophotographic photosensitive member, the agent applying means is an electronic means. It is characterized in that it is brought into contact with the surface of the photographic photoreceptor.

Here, the surface energy lowering agent refers to a substance that adheres to the surface of the electrophotographic photosensitive member and reduces the surface energy of the electrophotographic photosensitive member. Specifically, by adhering to the surface, the electrophotographic photosensitive member A material that increases the contact angle (contact angle with pure water) of the surface of 1 ° or more.

Surface contact angle measurement The contact angle of the surface of the photoconductor was measured with a contact angle meter (CA-DT.A type: manufactured by Kyowa Interface Science Co., Ltd.) under an environment of 30 ° C. and 80% RH. To do.

By the way, as the surface energy lowering agent, a fatty acid metal salt or a fluororesin can be mentioned. However, these materials have a water content under high temperature and high humidity conditions due to hydrophilic groups and impurity components in the materials. It tends to increase. When the water content is high, these surface energy lowering agents are not evenly spread on the surface of the photoreceptor, and the effects of the present invention described above cannot be sufficiently exhibited. The surface energy lowering agent used in the present invention has a water content of 5.0% by mass or less under the environment of 30 ° C. and 80% RH under the high temperature and high humidity condition, and therefore the effect of the present invention can be sufficiently exhibited. You can

As the surface energy lowering agent, the contact angle of the surface of the electrophotographic photosensitive member (contact angle with pure water) is 1
The material is not limited to a fatty acid metal salt, a fluorine-based resin, or the like as long as it is a material that increases by more than °.

The surface energy lowering agent used in the present invention is most preferably a fatty acid metal salt as a material having spreadability on the surface of the photoreceptor and uniform film forming performance. The fatty acid metal salt is preferably a metal salt of a saturated or unsaturated fatty acid having 10 or more carbon atoms. For example, aluminum stearate, indium stearate, gallium stearate,
Examples thereof include zinc stearate, lithium stearate, magnesium stearate, sodium stearate, aluminum palmitate, and aluminum oleate, and more preferably metal stearate.

Among the above fatty acid metal salts, the fatty acid metal salt having a particularly high outflow rate of the flow tester has high cleavability, and the fatty acid metal salt layer can be more effectively formed on the surface of the photoreceptor of the present invention. Outflow rate range is 1 x
It is preferably 10 ⁻⁷ or more and 1 × 10 ⁻¹ or less, and most preferably 5 × 10 ⁻⁴ or more and 1 × 10 ⁻² or less. The flow rate of the flow tester is measured by Shimadzu Flow Tester "CFT-50".
0 ”(manufactured by Shimadzu Corporation).

Further, as another example of the above-mentioned solid material, a fluororesin powder such as polyvinylidene fluoride and polytetrafluoroethylene is preferable. These solid materials are preferably used in the form of a plate or rod by applying pressure as necessary.

On the other hand, in the case of the surface energy lowering agent, this material was put in a petri dish at 30 ° C. and 80
After being left in% RH for 24 hours, it is measured using a Karl Fischer moisture meter (manufactured by Kyoto Electronics Manufacturing Co., Ltd .; MKA-3p).

The surface energy reducing agent of the present invention can be adjusted to a water content of 5.0% by mass or less by controlling hydrophilic components and impurities in the material, for example, refining and hydrophobizing treatment to obtain high temperature and high humidity (30 ° C.). In addition to reducing the water content under 80% RH,
This can be achieved by mixing a water content adjusting agent, high temperature drying treatment, and the like.
The water content of the water content is preferably 0.01 to 5.0% by mass, and more preferably 0.05 to 3.0% by mass. On the contrary, if it is less than 0.01% by mass, it tends to be affected by environmental changes due to temperature rise during copying, especially humidity depending on the location of the image bearing member, and it is difficult to select a material and make hydrophobic treatment. If it is more than 5.0% by mass, hollow dots and character dust are likely to occur.

The electrophotographic photosensitive member of the present invention has a ten-point surface roughness R
It is preferable that z is 0.05 to 4.0 μm. By setting the ten-point surface roughness of the photoconductor within the above range,
The surface energy lowering agent is uniformly supplied to the surface of the photoconductor from the agent applying means, and is uniformly spread on the surface of the photoconductor to form a film. It is possible to prevent the occurrence of character dust and the deterioration of sharpness.

Ten-Point Surface Roughness Rz of Electrophotographic Photosensitive Member (Definition and Measuring Method of Ten-Point Surface Roughness Rz) Rz of the present invention is JISB.
It means a value of a reference length of 0.25 mm described in 0601-1982. That is, it is the difference between the average height of the top five peaks and the average height of the five bottom valleys over the distance of the reference length of 0.25 mm.

In the examples described later, the ten-point surface roughness Rz is measured by a surface roughness meter (Surforder S manufactured by Kosaka Laboratory Ltd.).
E-30H). However, another measuring device may be used as long as the measuring device produces the same result within the error range.

The ten-point surface roughness Rz of the electrophotographic photosensitive member is adjusted to 0.05 to 4.0 μm by the method of adjusting the surface roughness of the support constituting the electrophotographic photosensitive member or the surface layer of the electrophotographic photosensitive member. It becomes possible by adjusting the roughness. In particular, a method of incorporating various fine particles into a layer constituting the surface layer of the electrophotographic photosensitive member to adjust the surface roughness is effective.

The ten-point surface roughness Rz of the photoconductor is 0.05.
It is effective to control the surface roughness of the conductive support constituting the photoconductor to be appropriately rough as a method for controlling the surface roughness within the range of up to 4.0 μm.

Materials for the conductive support used in the present invention are mainly aluminum, copper, brass, steel,
A metal material such as stainless steel or other plastic material molded into a belt shape or a drum shape is used. Among them, aluminum, which is excellent in cost and workability, is preferably used, and a thin-walled cylindrical aluminum element tube that is usually extruded or pultruded is often used.

The conductive support used in the present invention preferably has a ten-point average surface roughness Rz of more than 0.1 μm and not more than 6.0 μm. More preferably, it is 0.2 μm or more and 5.0 μm or less. The surface roughness can be adjusted by coating an intermediate layer or a photosensitive layer described below on a support having such a surface roughness.

As a method of roughening the surface of the support as described above, a method of scraping the surface of the support with a cutting tool or the like or a method of colliding fine particles with the surface of the support is used.
Sandblasting method, processing method by ice particle cleaning device described in JP-A-4-204538, JP-A-9-
There is a honing method described in No. 236937.
In addition, an anodizing method, an alumite treatment method, a buffing method, a laser ablation method described in JP-A-4-233546, a method using a polishing tape described in JP-A-8-1502, and The method of roller burnishing processing described in No. -1510 and the like can be mentioned. However, the method of roughening the surface of the support is not limited to these.

As another method of roughening the surface of the photoconductor, a method of adding fine particles having a number average particle diameter of 0.05 to 8 μm to the surface layer of the photoconductor can be considered. For example, JP-A-8-2
It is possible to adjust the ten-point surface roughness of the photoconductor to the above range by dispersing and containing the inorganic fine particles subjected to the hydrophobic treatment as described in 48663 in the surface layer of the photoconductor. As a method of hydrophobizing the inorganic fine particles, a method of treating with a hydrophobizing agent such as a titanium coupling agent, a silane coupling agent, a polymeric fatty acid or a metal salt thereof can be used.

As the above-mentioned fine particles, as organic fine particles,
Examples thereof include fine particles of polyacrylate, polymethacrylate, polymethylmethacrylate, polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene and the like.

Examples of the inorganic fine particles include silica, titanium oxide, alumina, barium titanate, calcium titanate, strontium titanate, zinc oxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate and silicon carbide. Examples thereof include fine particles of silicon nitride, chromium oxide, red iron oxide and the like.

The inorganic fine particles are preferably subjected to a hydrophobizing treatment. The hydrophobizing treatment can be carried out by reacting the inorganic fine particles and the hydrophobizing agent at a high temperature. The hydrophobic treatment agent is not particularly limited, for example, hexamethyldisilazane, dimethyldichlorosilane, decylsilane, dialkyldihalogenated silane, trialkylhalogenated silane, silane coupling agents such as alkyltrihalogenated silane and dimethyl. Silicon oil etc. are mentioned. The amount of the hydrophobizing agent varies depending on the type of the fine particles and the like and cannot be specified unconditionally, but generally, the greater the amount, the higher the degree of hydrophobicity. It is also effective to remove the hygroscopic substance by, for example, reprecipitation or heat treatment.

The number average particle diameter of fine particles is 5 nm to 8 μm.
Is preferred. Furthermore, 10 nm to 6 μm is preferable. The number average particle diameter is 2000 when observed by a transmission electron microscope.
It is a value obtained by doubling and observing 100 particles at random as primary particles, and measuring the average diameter in the Feret direction by image analysis.

Next, the photoreceptor of the present invention will be described.
In the present invention, the photoconductor is an electrophotographic photoconductor used for electrophotographic image formation, and the effect of the present invention is remarkably exhibited when an organic electrophotographic photoconductor (organic photoconductor) is used. The organic photoconductor means an electrophotographic photoconductor composed of an organic compound having at least one of a charge generation function and a charge transport function, which are indispensable for the construction of the electrophotographic photoconductor. It includes all known organic electrophotographic photoreceptors such as a photoreceptor formed of a substance or an organic charge transport material, a photoreceptor formed of a polymer complex having a charge generation function and a charge transport function.

The constitution of the organic photoreceptor used in the present invention will be described below. Conductive Support As the conductive support used in the photoreceptor of the present invention, either a sheet shape or a cylindrical shape may be used, but in order to design the image forming apparatus compactly, the cylindrical conductive support is used. Is preferred.

The cylindrical conductive support of the present invention means a cylindrical support required to form an image endlessly by rotating, and has a straightness of 0.1 mm or less and a shake of 0.1 mm or less. Conductive supports in the range are preferred. When the circularity and the shake range are exceeded, good image formation becomes difficult.

As the conductive material, a metal drum of aluminum, nickel or the like, a plastic drum having aluminum, tin oxide, indium oxide or the like deposited thereon, or a paper / plastic drum coated with a conductive substance can be used. It is preferable that the conductive support has a specific resistance of 10 ³ Ωcm or less at room temperature.

Intermediate Layer In the present invention, an intermediate layer having a function of improving adhesiveness to the photosensitive layer and an electric barrier function may be provided between the conductive support and the photosensitive layer. Is mentioned. The film thickness of the intermediate layer using the curable metal resin is preferably 0.1 to 5 μm.

Photosensitive Layer The photosensitive layer structure of the photoconductor of the present invention may be a photosensitive layer structure having a single layer structure in which one layer has a charge generating function and a charge transporting function on the above-mentioned intermediate layer, but is more preferably photosensitive. It is preferable that the function of the layer is separated into a charge generation layer (CGL) and a charge transport layer (CTL). By adopting a constitution in which the functions are separated, the increase in residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negative charging photoreceptor, the charge generation layer (C
GL) and a charge transport layer (CTL) thereon. In the case of the photoconductor for positive charging, the order of the layers is the reverse of that of the photoconductor for negative charging. The most preferable photosensitive layer structure of the present invention is a negatively charged photosensitive member structure having the above-mentioned function separation structure.

The constitution of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below. Charge Generation Layer The charge generation layer contains a charge generation material (CGM). If necessary, a binder resin and other additives may be contained as other substances.

As the charge generating substance (CGM), a known charge generating substance (CGM) can be used. For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azurenium pigment or the like can be used. Among these, CGM that can minimize the increase in residual potential with repeated use
Has a steric structure and a potential structure capable of forming a stable aggregation structure among a plurality of molecules, and specific examples thereof include a phthalocyanine pigment and a perylene pigment CGM having a specific crystal structure. For example, the Bragg angle 2θ with respect to Cu-Kα rays
CGMs such as titanyl phthalocyanine having a maximum peak at 27.2 ° and benzimidazole perylene having a maximum peak at 22.4 at 27.2 have almost no deterioration due to repeated use, and the residual potential increase can be reduced.

When a binder is used as a CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferable resin is a formal resin, a butyral resin, a silicone resin, a silicone-modified butyral resin, or a phenoxy resin. Resin etc. are mentioned. The ratio of the binder resin to the charge generating substance is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential due to repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 2 μm.

Charge Transport Layer The charge transport layer contains a charge transport material (CTM) and a binder resin for dispersing CTM to form a film. Other substances may optionally contain additives such as antioxidants.

As the charge transport material (CTM), a known charge transport material (CTM) can be used. For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. Among these, CTM that can minimize the increase in residual potential due to repeated use has high mobility and has a characteristic that the difference in ionization potential with CGM to be combined is 0.5 (eV) or less, and preferably 0. It is 0.25 (eV) or less.

The ionization potentials of CGM and CTM are measured by a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).

Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd. Resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of the repeating units of these resins. In addition to these insulating resins, poly-
Examples include polymer organic semiconductors such as N-vinylcarbazole. The most preferable binder for these CTLs is a polycarbonate resin. The thickness of the charge transport layer is preferably 10-40 μm.

Protective Layer Various resin layers can be provided as a protective layer of the photoreceptor. In particular, by providing a crosslinked resin layer, the organic photoreceptor of the present invention having high mechanical strength can be obtained.

[0102]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto. In addition, "part" in the following text represents a mass part.

Preparation of Photoreceptor Preparation of Photoreceptor 1 On a cylindrical aluminum substrate obtained by drawing, the following dispersion was prepared and applied to form a conductive layer having a dry film thickness of 15 μm. <Conductive layer (PCL) composition liquid> Phenolic resin 160 parts Conductive titanium oxide pigment 200 parts Methyl cellosolve 100 parts The following intermediate layer composition liquid was prepared. This composition liquid was applied onto the conductive layer by a dip coating method to form an intermediate layer having a film thickness of 1.0 μm. <Intermediate layer (UCL) composition liquid> Polyamide resin (Amilan CM-8000: manufactured by Toray) 60 parts Methanol 1600 parts 1-Butanol 400 parts The following coating composition liquids are mixed and dispersed for 10 hours using a sand mill to generate charges. A layer coating solution was prepared. This coating solution is applied onto the intermediate layer by a dip coating method to give a dry film thickness of 0.2 μm.
m charge generating layer was formed. <Charge Generation Layer (CGL) Composition Liquid> Oxytitanyl phthalocyanine pigment (Cu-Kα characteristic X-ray has a maximum peak angle of 2θ of 27.3 at 2θ of 27.3) 60 parts Silicone resin solution (KR5240, 15% xylene-butanol solution) : Manufactured by Shin-Etsu Chemical Co., Ltd.) 700 parts 2-butanone 2000 parts The following coating composition liquids were mixed and dissolved to prepare a charge transport layer coating liquid. This coating solution is applied onto the charge generation layer by a dip coating method to form a charge transport layer having a dry film thickness of 20 μm,
A photoconductor 1 was produced. Rz of the photoconductor was 0.07 μm. <Charge transport layer (CTL) composition liquid> Charge transport material (N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine) 200 parts Bisphenol Z-type polycarbonate (Iupilon Z300 : Mitsubishi Gas Chemical Co., Ltd., methanol once refined product) 300 parts 1,2-dichloroethane 2000 parts Preparation of photoconductor 2 Bit-cut ten-point surface roughness Rz 0.1 μm on a cylindrical aluminum substrate, the following intermediate layer: The composition liquid was applied by dipping and dried at 150 ° C. for 30 minutes to form an intermediate layer having a thickness of 1.0 μm.

<Interlayer (UCL) composition liquid> Zirconium chelate compound ZC-540 (Matsumoto Pharmaceutical Co., Ltd.) 200 parts Silane coupling agent KBM-903 (Shin-Etsu Chemical Co., Ltd.) 100 parts Methanol 700 parts Ethanol 300 parts below The coating composition liquids were mixed and dispersed using a sand mill for 10 hours to prepare a charge generation layer coating liquid. This coating solution is applied onto the intermediate layer by a dip coating method to give a dry film thickness of 0.2 μm.
m charge generating layer was formed. <Charge Generation Layer (CGL) Composition Liquid> Oxytitanyl phthalocyanine pigment (Cu-Kα characteristic X-ray has a maximum peak angle of 2θ of 27.3 at 2θ of 27.3) 60 parts Silicone resin solution (KR5240, 15% xylene-butanol solution) : Manufactured by Shin-Etsu Chemical Co., Ltd.) 700 parts 2-butanone 2000 parts The following coating composition liquids were mixed and dissolved to prepare a charge transport layer coating liquid. This coating solution was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a film thickness of 20 μm, and a photoconductor 2 was produced. Rz of the photoreceptor was 3.0 μm.

<Charge Transport Layer (CTL) Composition Liquid> Charge Transport Material (N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine) 200 parts Bisphenol Z-type polycarbonate (Upilon Z300: manufactured by Mitsubishi Gas Chemical Co., Inc.) 300 parts 1,2-dichloroethane 2000 parts Teflon (R) fine particles (heat-treated product having an average particle size of 5 μm) 100 parts Preparation of photoconductor 3 The following coating composition liquids are mixed and dissolved. Then, a protective layer coating composition was prepared and coated on the CTL of the photoconductor 2.

<Protective Layer (OCL) Composition Liquid> Molecular Sieve 4A was added to 10 parts by mass of a polysiloxane resin consisting of 80 mol% of methyl siloxane unit and 20 mol% of methyl-phenyl siloxane unit, and allowed to stand for 24 hours for dehydration treatment. did. This resin was dissolved in 10 parts by mass of toluene, and 5 parts by mass of methyltrimethoxysilane and 0.2 parts by mass of dibutyltin acetate were added thereto to form a uniform solution. Dihydroxymethyltriphenylamine (compound below) 6
Then, parts by mass were added and mixed, and this solution was applied as a protective layer having a dry film thickness of 2 μm, followed by heating and curing at 130 ° C. for 1 hour to prepare a photoreceptor 3. Rz of the photoconductor is 1.3 μm
Met.

[0107]

[Chemical 1]

Preparation of Photoreceptor 4 On a cylindrical aluminum substrate having a ten-point surface roughness Rz of 0.5 μm, which was cut with a cutting tool, the following intermediate layer composition liquid was applied by a dip coating method to form an intermediate layer having a dry film thickness of 2 μm. did.

<Intermediate layer (UCL) composition liquid> The following intermediate layer dispersion liquid was diluted twice with the same mixed solvent, and allowed to stand overnight and then filtered (filter; Rigimesh filter manufactured by Nippon Pall Ltd. nominal filtration accuracy: 5 microns). , Pressure; 0.05 MPa)
Then, an intermediate layer composition liquid was prepared.

(Preparation of Intermediate Layer Dispersion) Polyamide Resin CM8000 (Toray) 1 Part Titanium Oxide SMT500SAS (Taika; Surface Treatment: Silica Treatment, Alumina Treatment, and Methyl Hydrogen Polysiloxane Treatment) 3.0 Part Methanol 10 parts Dispersion was carried out batchwise with a sand mill as a disperser for a dispersion time of 10 hours to prepare an intermediate layer dispersion liquid.

The following composition liquids were mixed and dispersed using a sand mill to prepare a charge generation layer composition liquid. This composition liquid was applied by a dip coating method to form a dry film thickness of 0.3 μm on the intermediate layer.
m charge generating layer was formed. <Charge Generating Layer (CGL) Composition Liquid> Oxytitanyl phthalocyanine pigment (Cu-Kα characteristic X-ray has a maximum peak angle of 2θ of 27.3 of 27.3) 20 parts Polyvinyl butyral (# 6000-C, Denki Kagaku Kogyo Co., Ltd.) 10 parts t-butyl acetate 700 parts 4-methoxy-4-methyl-2-pentanone 300 parts The following composition liquids were mixed and dissolved to prepare a charge transport layer composition liquid. This composition liquid is applied onto the charge generation layer by a dip coating method to form a charge transport layer having a film thickness of 24 μm.
Was produced. Rz of the photoconductor was 0.2 μm.

<Charge Transport Layer (CTL) Composition Liquid> Charge Transport Material (N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine) 75 Parts Polycarbonate Resin (Iupilon Z300, manufactured by Mitsubishi Gas Chemical Co., Ltd.) 100 parts Methylene chloride 750 parts Silica (average particle size 0.5 μm, treated with silicone oil) 20 parts Preparation of photoconductor 5 Instead of silica fine particles in the charge transport layer of photoconductor 4, average particles are used. A photoconductor 5 was prepared in the same manner as the photoconductor 4 except that the diameter was 5 μm. Rz was 4.3 μm.

Preparation of Photoreceptor 6 A photoreceptor 6 was prepared in the same manner as the photoreceptor 4, except that the substrate of the photoreceptor 4 was a mirror finished product of Rz 0.001 μm and silica fine particles were not used for CTL. Rz was 0.03 μm.

Preparation of surface energy reducing agents A to F Sodium stearate was dissolved in water to prepare a 15 mass% liquid. Further, zinc sulfate was dissolved in water to prepare a 25 mass% liquid. A 2-liter receiving vessel with a stirring device having a turbine blade with a diameter of 6 cm was prepared, and the turbine blade was rotated at 350 rpm. A sodium stearate solution was added to this receiving container to adjust the solution temperature to 80 ° C. Next, a zinc sulfate solution heated to 80 ° C. was dropped into this receiving container over 30 minutes. The equivalent ratio of sodium stearate and zinc sulfate was 0.98, and the metal soap slurry was mixed so as to have an amount of 500 g. After the completion of the charging of the whole amount, the reaction was terminated by aging it for 10 minutes at the temperature condition during the reaction. The metal soap slurry thus obtained was then washed twice with water and subsequently with water. 1 piece of the obtained metal soap cake
It was dried at a drying temperature of 10 ° C. and solidified at a pressure of 150 kg / cm ² . Then, the solid material of zinc stearate (surface energy lowering agents A to F) was allowed to stand for 24 hours under the environmental condition of 30 ° C. and 80% RH, and the water content shown in Table 1 was changed.
Got The water content of these A to F was adjusted by changing the drying time at 110 ° C.

Preparation of Surface Energy Lowering Agent G Commercially available Teflon (R) fine particles were added at 80 ° C. and 200 kg / c.
m ² was heated and pressure-treated to obtain a solid material. The solid material was left under an environmental condition of 30 ° C. and 80% RH for 24 hours to obtain a Teflon (R) solid material (surface energy lowering agent G) having a water content of 0.8 mass%.

[0116]

[Table 1]

<Evaluation> The cleaning means shown in FIG. 5 is mounted as a cleaning means for the photosensitive member of the digital color printer having the intermediate transfer member of FIG. 1, and the combination of the photosensitive member and the surface energy lowering agent is added to the digital color printer. The Rz of the intermediate transfer member and the biting amount of the cleaning brush are combined as shown in Table 2, and high temperature and high humidity (30 ° C
Under 80% RH), images having a pixel ratio of 8% were continuously printed on 100,000 sheets of A4 paper and evaluated. Evaluation items are void,
Evaluation of character dust, cleaning property evaluation, image evaluation, and the like. The evaluation items and evaluation criteria are shown below. The evaluation results are shown in Table 2.

Evaluation Items and Evaluation Criteria Measurement of Contact Angle of Photoreceptor After the above 100,000 prints were evaluated, the contact angle of the surface of the photoreceptor with pure water was measured by a contact angle meter (CA-DT / A type: manufactured by Kyowa Interface Science Co., Ltd.). ) Was used in the environment of 30 ° C. and 80% RH.

The character "occurrence of void" was enlarged and observed, and the presence or absence of void was visually observed.

The evaluation criteria are: ⊚: No noticeable voids occurred until the end of 100,000 prints ◯: No noticeable voids until the end of 50,000 prints ×: Less than 50,000 prints "Evaluation of character dust" with remarkable occurrence of voids Instead of the dot image forming the character, a 10% halftone dot image was formed on the entire surface of the image, and toner scattering around the dot was observed with a magnifying glass.

Rank ⊚: Toner scattering is small until 100,000 sheets have been printed. Rank A: Scattering of toner is small until the end of printing of 50,000 sheets.

Rank x: Toner scattering is increased in prints of less than 50,000 sheets. (Level of Practical Problems) Evaluation of Cleaning Property The presence or absence of occurrence of toner slipping due to abrasion of the photoconductor and the cleaning blade and the occurrence of blade curl (phenomenon of blade reversal) were evaluated.

⊚: Toner slip-through and blade curl did not occur until the end of printing 100,000 sheets. ○: Toner pass-through and blade curl did not occur until the end of printing of 50,000 sheets. ×: Toner was lost after printing less than 50,000 sheets. Occurrence of slip-through or blade curl Occurrence of image quality Evaluation was performed mainly on whether each color density is sufficiently high or image sharpness (whether the image is clear or rough).

Image Density (Measured using RD-918 manufactured by Macbeth Co., measured with relative reflection density with paper reflection density set to "0") A: Y, M, C, K (black) 1 2 or more ○: 0.8 or more for both Y, M, C and K ×: At least one of Y, M, C and K is less than 0.8 Image sharpness Reproducibility of fine lines and image sharpness at high temperature Humid environment (temperature 3
An image was displayed at 3 ° C. and a relative humidity of 50%), and the characters were evaluated as broken. A 3-point and 5-point character image was formed and evaluated according to the following criteria.

◎: 3 points, 5 points are clear and easily readable ○: 3 points are partially unreadable, 5 points are clear and easily readable ×: 3 points are almost unreadable, 5 Some or all points are not readable Other evaluation conditions Image forming line speed L / S: 180 mm / s Charging condition of photoconductor (60 mmφ): Potential of non-image part
It is detected by an electric potential sensor so that it can be feedback-controlled, and its controllable range is -500V to -900V, and the surface potential of the photoconductor in the case of full exposure is -50 to 0V.
It was in the range of.

Image exposure light: semiconductor laser (wavelength: 780n
m) Development conditions: The developer is a two-component developer of toner and carrier having a number average particle size of 7.5 μm for each of Y, M, C and K, and the developing device is of a system corresponding to the two-component developer. Is.

Intermediate transfer member: A seamless endless belt-shaped intermediate transfer member 70 was used, and a belt made of a semiconductive resin having a volume resistivity of 1 × 10 ⁸ Ω · cm was used. Rz is 0.9
Two types, μm and 1.5 μm, were used.

Primary Transfer Conditions Primary Transfer Roller (5Y, 5M, 5C, 5K (6.05 mmφ in FIG. 1) in FIG. 1): Structure in which a core metal is attached with elastic rubber: Surface specific resistance 1 × 10 ⁶ Ω, transfer voltage applied Secondary transfer conditions An endless belt-shaped intermediate transfer member 70 as an intermediate transfer member, a backup roller 74 and a secondary transfer roller 5A are arranged so as to sandwich it, and the resistance value of the backup roller 74 is 1 × 10 ⁶ Ω. The resistance value of the secondary transfer roller as the secondary transfer means is 1 × 10 ⁶ Ω, and the constant current control (about 8
0 μA).

The fixing is a heat fixing method using a fixing roller having a heater inside the roller. The distance Y on the intermediate transfer member from the first contact point between the intermediate transfer member and the photoconductor to the first contact point between the next color photoconductor and the next color photoconductor was set to 95 mm.

Drive roller 71, guide rollers 72, 73
Also, the outer peripheral length (circumferential length) of the backup roller 74 for secondary transfer is set to 31.67 mm (= 95 mm / 3), and the outer peripheral length of the tension roller 76 is set to 23.75 mm.
(= 95 mm / 4).

Then, the outer peripheral length of the primary transfer roller is set to 19
mm (= 95 mm / 5). Cleaning blade (photoreceptor) Cleaning brush: conductive acrylic resin, brush bristle density (3 × 10 ³ / cm ² ), bite amount 0.6, 1.0,
Three types of 1.3 mm were used.

Secondary transfer roller (5A in FIG. 1): Structure in which elastic rubber is attached to core metal: Transfer voltage application cleaning blade (intermediate transfer member)

[0133]

[Table 2]

As is clear from Table 2, 4.5% by mass
Combinations 1 to 5 and 7 to 12 in the present invention supplied with the surface energy lowering agent having the following water content are compared with the combination 6 supplied with the surface energy lowering agent of 5.5 mass% water content other than the present invention. However, the whole evaluation item including the blank and the character dust has been improved. In particular, combinations 1 to 5 and 7 to 10 in the present invention in which the surface energy lowering agent having a water content of 4.5% by mass or less and the ten-point surface roughness Rz of the photoreceptor are 0.07 to 3.0 μm are Compared to the combination 6 other than the invention, the improvement effect is remarkable. Further, the combination of the present invention is a combination 1 which does not use a surface energy lowering agent.
Compared with No. 3, good results are shown for almost all evaluation items.

[0135]

EFFECTS OF THE INVENTION By using the present invention, it is possible to improve the toner transfer characteristics of an electrophotographic system using an intermediate transfer member, and it is possible to prevent image defects such as hollow spots and character dust caused by a decrease in toner transfer. Further, it is possible to provide an electrophotographic image forming apparatus having good cleaning properties.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention.

FIG. 2 is an example of a cleaning unit for an intermediate transfer member.

FIG. 3 is a layout diagram showing a positional relationship among a photosensitive member, an endless belt-shaped intermediate transfer member, and a primary transfer roller.

FIG. 4 is a layout diagram showing a positional relationship among a backup roller, an endless belt-shaped intermediate transfer member, and a secondary transfer roller.

FIG. 5 is a configuration diagram of a cleaning unit installed on the photoconductor of the present invention.

[Explanation of symbols]

1Y, 1M, 1C, 1K Photoreceptors 2Y, 2M, 2C, 2K Charging means 3Y, 3M, 3C, 3K Exposure means 4Y, 4M, 4C, 4K Developing means 5A Secondary transfer roller (secondary transfer means) 5Y, 5M , 5C, 5K Primary transfer roller (primary transfer means) 6, 6A, 6Y, 6M, 6C, 6K Cleaning means 7 Endless belt-shaped intermediate transfer body unit 10Y, 10M, 10C, 10K Image forming section 61 Blade 62 Bracket 63 Support shaft 70 Endless belt-shaped intermediate transfer member

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 5/147 503 G03G 5/147 503 15/16 15/16 (72) Inventor Shigeki Takeuchi Hachioji, Tokyo 2970 Ishikawacho Konica Stock Company F-term (reference) 2H035 CA07 CB03 2H068 AA04 AA09 AA14 AA29 BA57 BB31 CA06 FC20 2H134 GA01 GA06 GB02 HB00 HD00 HD17 KG08 KH01 LA01 2H200 FA02 GA12 GA16 GA23 GA34 GA02 GB21 GB13 GB12 GB13 GB12 GB13 GB02 GB12 GB13 GB02 JC12 JC15 JC16 JC17 LB12 LB13 LB35 MA03 MA04 MA14 MA20 MB06 MC06 MC08

Claims (9)

[Claims] 1. An image forming apparatus equipped with a transfer means for transferring a toner image formed on an electrophotographic photosensitive member onto a recording material, comprising an agent applying means for applying a surface energy lowering agent to the surface of the electrophotographic photosensitive member. An image forming apparatus having the surface energy lowering agent having a water content of 5.0 mass% or less. 2. A ten-point surface roughness Rz of the electrophotographic photosensitive member.
Is 0.05 to 4.0 [mu] m, the image forming apparatus according to claim 1. 3. A primary transfer means for transferring a toner image formed on an electrophotographic photosensitive member onto an intermediate transfer body, and a secondary transfer means for transferring the toner image transferred onto the intermediate transfer body onto a recording material. In the image forming apparatus, a means for applying a surface energy reducing agent to the surface of the electrophotographic photosensitive member is provided, and the water content of the surface energy reducing agent is 5.0% by mass or less. Image forming apparatus. 4. The ten-point surface roughness Rz of the electrophotographic photosensitive member.
Is 0.05 to 4.0 μm, the image forming apparatus according to claim 3. 5. The image forming apparatus according to claim 1, wherein the surface energy lowering agent is a fatty acid metal salt. 6. The image forming apparatus according to claim 5, wherein the fatty acid metal salt is zinc stearate. 7. The image forming apparatus according to claim 1, wherein the surface energy lowering agent is a fluorine-based resin containing a fluorine atom. 8. The image forming apparatus according to claim 1, wherein the surface layer of the electrophotographic photosensitive member contains fine particles having a number average particle diameter of 5 nm to 8 μm. 9. An image forming method, wherein an electrophotographic image is formed by using the image forming apparatus according to claim 1.