JP2000267321A - Electrophotographic photoreceptor and electrophotographic apparatus using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the electrophotographic photoreceptor enhanced in the performance of toner transfer from the photoreceptor to the body to be transferred and image quality and the durability of the photoreceptor. SOLUTION: This electrophotographic photoreceptor 10 has a lamination structure of a photosensitive layer 14 and a 10-30 nm thick barrier layer 13 and an elastic layer 12, and as the other embodiment, the photoreceptor 10 has the lamination structure of a surface releasable layer 17 and a 5-100 nm thick compatible layer 16 and the photosensitive layer 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member and an electrophotographic apparatus using the same.

[0002]

2. Description of the Related Art In image formation by electrophotography,
The toner transfer efficiency when transferring the toner image formed on the photoreceptor to the transfer receiving body is one of the major factors that determine the image quality. If the transfer efficiency of 100% cannot be obtained, the toner on the photoreceptor is partially broken, and as a result, the image quality is reduced, such as a decrease in image density and image blur. Further, when the efficiency of transferring the toner from the photoconductor to the transfer target is low, it is necessary to use a stronger cleaning unit for removing the toner remaining on the photoconductor. In this case, the photoreceptor is considerably damaged by the cleaning means, and as a result, the life of the photoreceptor is reduced.

[0003] Here, a wet electrophotographic apparatus using a liquid developer has an advantage that cannot be realized by dry electrophotography, and its value is recently being reviewed. The main advantages of the wet electrophotography over the dry process are that it is possible to use a very fine toner having a submicron size, so that high image quality can be realized, and sufficient image density can be obtained with a small amount of toner. In addition, it is possible to realize a texture similar to that of printing (for example, offset printing), and to realize energy saving because toner can be fixed on paper at a relatively low temperature.

[0004] However, conventional liquid electrophotographic wet electrophotography has some essential problems. One problem is that since fine liquid toner is used, the toner adherence to the photoreceptor is strong, and the efficiency of toner transfer from the photoreceptor to the transfer target is not always sufficient. In the case of the so-called offset transfer method, in which toner is transferred from a photoconductor to a transfer target using heat or pressure, the toner transfer efficiency itself is electric field transfer (= toner transfer from the photoconductor to the transfer target is performed using an electric field. Transfer method), but
Even so, it has been difficult to achieve a toner transfer efficiency close to 100%. In particular, it has been found that when an attempt is made to transfer a toner image directly from a photoconductor to a sheet, the transfer efficiency is significantly reduced.

In order to solve such a problem of toner transferability, elasticity is imparted to the photoreceptor side, and a release layer is formed on the outermost surface of the photoreceptor. Photoreceptors having a "rigid layer" layer configuration have been proposed (US Pat. No. 5,608,507). At first glance, this configuration seems to be an effective layer configuration from the viewpoint of toner transfer efficiency. However, since the photosensitive layer and the elastic layer are adjacent to each other, when forming the photosensitive layer on the elastic layer, the elastic layer is dissolved, swells or shrinks due to the influence of a solvent, heat, or the like. The problem that uneven unevenness was formed on the surface became apparent. For this reason, although the toner transfer efficiency itself is improved, there is a problem that the image quality is reduced.

In order to improve toner transferability,
It has been proposed that a surface of a photoreceptor is coated with a silicone resin or a fluorine resin to form a surface release layer. Certainly, it is a fact that toner transfer efficiency can be enhanced by coating with a silicone resin or a fluorine resin. However, in practice, 100% transfer efficiency is not always obtained, and a considerable amount of transfer residue occurs. Therefore, it is necessary to clean the transfer residue using a cleaning unit. At this time, usually, the silicone resin or the fluororesin does not always have sufficient adhesiveness to the underlying photosensitive layer and the cohesive force of the surface release layer itself, and thus often wears and deteriorates during cleaning. In addition, even when there is no transfer residue, there is a problem that the surface release layer is deteriorated by the influence of heat and pressure during transfer.

[0007]

As described above, in the conventional electrophotographic apparatus, there is a problem that it is difficult to achieve both improvement of the toner transfer efficiency from the photosensitive member to the transfer receiving member and improvement of the image quality. there were. Another problem is that the durability of the surface release layer formed to improve the toner transferability is insufficient.

An object of the present invention is to provide an electrophotographic photoreceptor having good toner transferability from a photoreceptor to a transfer-receiving body and capable of obtaining a high-quality image, and an electrophotographic apparatus using the same. This is the first purpose. It is a second object of the present invention to provide an electrophotographic photoreceptor which has good toner transfer efficiency to a transfer target and has high durability, and an electrophotographic apparatus using the same.

[0009]

The present invention is characterized by comprising an elastic layer, a barrier layer having a thickness of 10 nm to 30 μm formed on the surface of the elastic layer, and a photosensitive layer formed on the surface of the barrier layer. The electrophotographic photosensitive member described above.

Further, the present invention provides a photoreceptor, a latent image forming means for forming an electrostatic latent image on the photoreceptor, and a developing device for supplying a liquid developer to the electrostatic latent image to make it visible. An electrophotographic apparatus comprising: a transfer unit configured to transfer a visible image formed on the photosensitive member by being pressed against the photosensitive member, wherein the photosensitive member is formed on an elastic layer and a surface of the elastic layer. 10
An electrophotographic apparatus comprising a barrier layer having a thickness of not less than nm and not more than 30 μm, and a photosensitive layer formed on the surface of the barrier layer.

Further, the present invention is an electrophotographic photoreceptor comprising a photosensitive layer and a release layer formed on the photosensitive layer and containing a release component and a compatible component. .
Further, the elastic layer and the 10n formed on the surface of the elastic layer
An electrophotographic photoreceptor comprising a barrier layer having a thickness of not less than m and not more than 30 μm, and the photosensitive layer formed on the surface of the barrier layer. Alternatively, the electrophotographic photoreceptor has an compatibility layer having a thickness of 5 nm or more and 100 nm or less containing a release layer component and a photosensitive layer component at an interface between the photosensitive layer and the release layer. Alternatively, the release component is an electrophotographic photosensitive member that is a silane coupling agent.

Further, the present invention provides a photosensitive member, a latent image forming means for forming an electrostatic latent image on the photosensitive member, and a developing device for supplying a liquid developer to the electrostatic latent image to visualize the electrostatic latent image. An electrophotographic apparatus comprising: a transfer unit for transferring a visible image formed on the photoconductor, the photoconductor being formed on the photosensitive layer. And a release layer containing a release component and a compatible component.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to obtain a high-quality image, it is necessary to efficiently transfer a toner image formed on a photosensitive member having good surface uniformity to a transfer-receiving member. In particular, a wet electrophotographic apparatus using a liquid developer composed of toner particles and a non-polar solvent uses finer toner particles than a dry apparatus, so that the toner adherence to the photoreceptor becomes stronger. Also in this case, it is important that the toner is transferred well from the photoconductor to the transfer target.

The inventors of the present invention have studied the structure of the photoreceptor for improving the toner transfer efficiency from the photoreceptor to the transfer-receiving body and for uniformly forming a high-quality image on the surface and bulk properties of the photoreceptor. Focusing on this, we conducted intensive studies. As a result, it was confirmed that the toner transfer efficiency was improved by the effect of the elastic layer when the photosensitive member had the layer configuration of the photosensitive layer / barrier layer / elastic layer.

Further, by interposing a barrier layer,
When the photosensitive layer was formed on the elastic layer, the elastic layer was not dissolved, swelled or shrunk under the influence of a solvent, heat, or the like, and the unevenness on the surface of the photosensitive member was extremely reduced. As a result, a high-quality image can be obtained uniformly.

That is, the barrier layer according to the present invention is not dissolved in a solvent used when forming an organic photosensitive layer,
In addition, those that do not penetrate this solvent, or that do not swell or shrink due to heat change during the formation of the photosensitive layer,
For example, if a metal film or the like is used, it further functions as a conductive layer.

Here, when the film thickness of the barrier layer was further examined, when the film thickness was smaller than a predetermined value (lower limit value), the effect of the barrier layer was reduced, so that the surface of the photoconductor was roughened. It has become clear that this will occur. Further, it has been found that when the barrier layer is larger than a predetermined value (upper limit), the effect of the underlying elastic layer is impaired, and the toner transfer efficiency is reduced. Thus, it was confirmed that there was an optimum range for the thickness of the barrier layer.

On the other hand, it is also important to improve the durability of the photoreceptor surface release layer, which is one method for improving the toner transfer efficiency. The present inventors have intensively studied various photoreceptor surface release layer materials. As a result, by including compatible components such as a silane coupling agent in the release layer, the components of the photosensitive layer serving as the base phase are compatible with each other in the release layer, and the adhesion between the photosensitive layer and the release layer is improved. It was found that the performance was improved. Here, when the film thickness of the compatible layer was further examined, when the film thickness was smaller than a predetermined value (lower limit value), the effect of the compatible layer was reduced, so that the adhesion of the surface release layer was reduced. Has been found to decrease. Also,
If the thickness of the compatible layer is larger than a predetermined value (upper limit value), the underlying photosensitive layer will be attacked, and as a result, the electrostatic characteristics of the photosensitive layer will be reduced. I understood. Thus, it was confirmed that there is an optimum range also in the thickness of the compatible layer.

Further, it was confirmed that the inclusion of the compatible component in the release layer increased the cohesive force of the release layer itself, improved the strength, and consequently improved the durability. Based on these facts, it has been found that the above problems can be solved by devising the layer structure and surface layer of the photoreceptor, and have completed the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an electrophotographic apparatus according to an embodiment of the present invention. The photoconductor 1 is a photoconductor drum in which an organic or inorganic photosensitive layer such as amorphous Si is provided on a conductive substrate. The photoreceptor 1 is uniformly charged by a well-known corona charger (corotron charger or scorotron charger) 2-1 and then receives an exposure beam 3-1 by an image-modulated laser or LED to form a surface. An electrostatic latent image is formed.

Thereafter, the electrostatic latent image is visualized by the developing device 4-1 containing the liquid developer. The liquid developer or toner particles adhering to the electrostatic latent image may be directly transferred to a sheet by a transfer device by a transfer process, but here, the second charger 2-2 and the second exposure beam 3- 2 forms a second electrostatic latent image, and stores a second developer of a different color from the liquid developer stored in the first developing device 4-1. By 2
Develop this. Therefore, two color toner images are formed on the photoconductor 1 after the second development. Similarly, the third and fourth developments are performed, and a full-color toner image is formed on the photoconductor 1.

The toner image is transferred to a sheet by the transfer device 5, and may be transferred directly to the sheet, or, as illustrated in FIG. May be transferred. The transfer from the photoreceptor 1 to the intermediate transfer member 6 and the transfer from the intermediate transfer member 6 to the paper 9 use a so-called offset transfer method using heat (heat and pressure as necessary). In general, many liquid developers can be fixed on paper at room temperature. However, fixing may be performed by heating the pressure roller 7 or the like.

On the other hand, the toner remaining on the photoconductor 1 is removed by the cleaner 8 from the photoconductor 1 after the transfer of the full-color toner image is completed. In such an electrophotographic apparatus, the present inventors improve the toner transfer efficiency from the photoreceptor 1 to the transfer target (the intermediate transfer member 6 or the paper 9) and uniformly form a high-quality image. For this purpose, the structure of the photoreceptor has been intensively studied, focusing on its surface physical properties and bulk physical properties.

As a result, the photosensitive layer / barrier layer / elastic layer 3
It was confirmed that the toner transfer efficiency was improved by the effect of the elastic layer by using the photoconductor having the layer structure. Also, by forming the photosensitive layer on the elastic layer using rubber or the like by interposing the barrier layer, the elastic layer is not dissolved, swelled or shrunk by the influence of a solvent, heat, or the like. As a result, the irregularities on the surface of the photoreceptor became extremely small. As a result, a high-quality image can be obtained uniformly.

Here, when the film thickness of the barrier layer was further studied, when the film thickness became smaller than 10 nm,
It has been clarified that unevenness occurs on the surface of the photoreceptor because the effect of the barrier layer is reduced. Further, it was found that when the barrier layer was larger than 30 μm, the effect of the underlying elastic layer was impaired, and the toner transfer efficiency was reduced. Thus, it was confirmed that there was an optimum range for the thickness of the barrier layer.

Further, the present inventors have studied a method for improving the toner transfer efficiency and the durability of the photosensitive member 1. In particular, attention was paid to the surface release layer of the photoreceptor, which is one method for improving the toner transferability, and intensive studies were made on a method for improving the durability of the surface release layer.

Here, the photosensitive layer itself generally has a relatively large surface energy, and the toner image formed on the photosensitive layer is in a state where it is difficult to transfer the toner image to a transfer target. Therefore, a surface release layer is provided on the photosensitive layer so that the surface energy is smaller than that of the photosensitive layer. In other words, the surface release layer is intended to facilitate the transfer of the toner formed on the photoreceptor to the transfer receiving member when considering the functions actually required as components of the electrophotographic apparatus. Therefore, it can be said that it is more preferable to define the surface release layer as "the surface layer of the photoreceptor having a surface energy smaller than the surface energy of the transfer-receiving member".

With respect to such a surface release layer, a method for improving the durability thereof was intensively studied. As a result, by using a compatible component that forms a compatible layer with the underlying photosensitive layer and a surface release layer material that can be used as a release component that reduces the surface energy, the surface release layer / compatible layer can be used. / Photosensitive layer having a three-layer structure of photosensitive layer can be realized, the adhesion of the surface release layer is improved, and the cohesive force of the release layer itself is also improved, and as a result, the durability is improved. It was confirmed that.

Here, the film thickness of the compatible layer composed of the photosensitive layer component, the release component and the compatible component was further examined. When the film thickness was smaller than 5 nm, the effect of the compatible layer was reduced. Therefore, it was found that the adhesion of the surface release layer was reduced. When the thickness of the compatible layer is 10
When it is larger than 0 nm, it has been found that the underlying photosensitive layer is eroded, and the electrostatic characteristics of the photoreceptor are reduced, so that a high-quality image cannot be obtained as a result. As described above, the optimum range of the thickness of the compatible layer (5 n
m or more and 100 nm or less).

The release layer capable of forming a compatible layer as described above is compatible with at least one resin selected from silicone resin, fluorosilicone resin and fluororesin as a release component. It can be formed by adding a silane coupling agent as a component, or using a coating liquid to which a silane coupling agent and a metal chelating agent are added. On the other hand, it is also possible to previously form only the silane coupling agent on the photosensitive layer, and then form the surface release layer using a coating solution to which the silane coupling agent has not been added, Although the adhesion is improved by this method, the cohesive force of the surface release layer itself is weak, so that the durability may be reduced.

As the silane coupling agent, vinyltrimethoxysilane, vinyltriethoxysilane, γ
-Chloropropyltrimethoxysilane, γ-chloropropylmethyldichlorosilane, γ-chloropropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (Β-aminoethyl) -aminopropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane , Γ-methacryloxypropylmethyldimethoxysilane and the like can be used.
-Aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane,
γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropylmethyldimethoxysilane are preferred. Further, as the metal chelating agent, an Sn-based chelating agent, a Ti-based chelating agent, an Al-based chelating agent, a Zr-based chelating agent, or the like can be used, and an Al-based chelating agent is preferable.

The thickness of the surface release layer is 0.5 μm or more and 3 μm or less from the viewpoint of not significantly reducing the electrostatic characteristics of the photosensitive layer and ensuring the abrasion resistance of the surface layer. It is desirable.

When a fluorine-based resin or a fluorosilicone-based resin is used alone, the film thickness tends to be thin. Therefore, it is preferable to mix the resin with a silicone-based resin in order to secure the film thickness. Further, fine particles such as silica may be mixed in order to improve the wear resistance of the surface layer.

[0034]

EXAMPLES Examples of the present invention will be specifically described below. Example 1 FIG. 2 shows a layer configuration of a photoreceptor according to Example 1 of the present invention. Thus, the photoconductor 10 includes the substrate 11, the conductive elastic layer 12,
It comprises a barrier layer 13 and a photosensitive layer 14.

The photoreceptor 10 was manufactured according to the following procedure. First,
As the substrate 11, an aluminum substrate having a thickness of 6 mm was used. A conductive urethane rubber sheet having a thickness of 0.2 mm and a JIA hardness of 40 degrees was bonded on the substrate 11 via a conductive adhesive. Here, a conductive urethane rubber sheet having a volume resistivity of 10 ⁷ Ω · cm was produced by dispersing carbon fine particles in urethane rubber. As the barrier layer 13, a 200-nm-thick Al vapor-deposited film was formed by an electron beam vapor deposition method. Then, in order to form an organic photosensitive layer containing phthalocyanine-based pigment, aromatic amine and polycarbonate (binder resin) as main components, these components are converted to T
A coating solution dissolved in HF (tetrahydrofuran) was prepared, and a film was formed by dip coating. After air-drying for 10 minutes, a heat treatment was performed at 90 ° C. for 1 hour to form an organic photosensitive layer 14 (about 20 μm thick), thereby completing the photoreceptor 10.

A visible image was formed on the photoreceptor 10 produced by the above procedure using a liquid developer, and heat and pressure transfer (offset transfer) was performed on an intermediate transfer member made of urethane rubber. The heating temperature is 70 for both the intermediate transfer member and the photosensitive member.
° C. The pressure was set to 50 kg per lateral width (about 210 mm) of A4 paper, including the weight of the intermediate transfer member.
As a result, it was confirmed by weight measurement before and after transfer that a toner transfer efficiency of 100% was obtained as shown in Table 1.

The quality of the transferred image was evaluated quantitatively in the following procedure. First, 20 mm using cyan toner
A solid image of 20 mm was developed on a photoreceptor and transferred to an intermediate transfer member. Thereafter, the transferred image was read using a scanner, and an area of 20 mm × 20 mm was read by 2 mm.
The image was divided into small areas of × 2 mm, and the optical density of each small area was measured. Then, the optical density of the 100% -transferred small area is normalized to 100, and the average density (Cave.) And the standard deviation (σ) of the optical densities in the 100 divided small areas are calculated to perform quantitative evaluation of the image quality. Was. In this case, the image quality is determined to be higher as the average density is closer to 100 and the standard deviation is smaller. In this embodiment, as shown in Table 1, Cave. =
100, σ = 0, and it was confirmed that an ideal high-quality image was obtained.

Comparative Example 1 FIG. 5 shows a layer structure of a photoreceptor according to Comparative Example 1 of the present invention. In Comparative Example 1, a photoreceptor 10 was manufactured in the same procedure as in Example 1 except that no barrier layer was provided.

Then, heat and pressure transfer (offset transfer) to an intermediate transfer member made of urethane rubber was performed under the same conditions as in Example 1. As shown in Table 1, the toner transfer efficiency was 92%. It was found that the toner transferability was lower than in the case of Example 1.

Further, when the quantitative evaluation of the transferred image was performed in the same manner as in Example 1, as shown in Table 1, Cave. = 8
8, σ = 5, indicating that the image quality is lower than that of the first embodiment.

As described above, in Comparative Example 1, the lowering of the toner transferability and image quality than in Example 1 is because the barrier layer is not provided, and the coating liquid is not used when the photosensitive layer is formed. It is considered that the main cause is that the underlying conductive urethane rubber layer is eroded by THF (tetrahydrofuran), which is a solvent, and the flatness of the surface of the photoreceptor is impaired.

Comparative Example 2 In Comparative Example 2, a photosensitive member 19 was manufactured in the same procedure as in Example 1 except that the thickness of the barrier layer was changed to 8 nm.

Then, heat and pressure transfer (offset transfer) was performed on an intermediate transfer member made of urethane rubber under the same conditions as in Example 1. As shown in Table 1, the toner transfer efficiency was 98%. It was found that the toner transferability was slightly lower than in the case of Example 1.

When the quantitative evaluation of the transferred image was performed in the same manner as in Example 1, Cave. = 9 as shown in Table 1.
6, σ = 2, which indicates that the image quality is slightly lower than that of the first embodiment.

As described above, in the present comparative example 2, the toner transferability and the image quality are slightly lower than in the case of the first embodiment because the barrier layer is as thin as 8 nm, and local defects are generated. When the photosensitive layer is formed, the conductive urethane rubber layer as a base is partially affected by THF (tetrahydrofuran) as a solvent of the coating solution, and as a result, the flatness of the surface of the photosensitive member is partially reduced. It is considered that the main cause is damage to

Comparative Example 3 In Comparative Example 3, the film thickness 5
Photoconductor 24 was prepared in the same manner as in Example 1, except that a barrier layer made of copper of 0 μm was formed.

Then, heat and pressure transfer (offset transfer) to an intermediate transfer member made of urethane rubber was performed under the same conditions as in Example 1. As shown in Table 1, the toner transfer efficiency was 82%. It was found that the toner transferability was significantly reduced as compared with the case of Example 1.

Further, when the image was quantitatively evaluated in the same manner as in Example 1, as shown in Table 1, Cave. = 80,
σ = 10, which indicates that the image quality is greatly reduced as compared with the first embodiment.

As described above, in Comparative Example 3, Example 1
It is considered that the reason why the toner transferability and the image quality are greatly reduced as compared with the case of the above is that the effect of the underlying elastic layer is reduced because the thickness of the barrier layer is as large as 50 μm.

[0050]

[Table 1]

Embodiment 2 FIG. 3 shows a layer structure of a photoreceptor according to Embodiment 2 of the present invention. As described above, the photoreceptor 10 includes the conductive substrate 11, the photosensitive layer 14, the compatible layer 16, and the surface release layer 17. The photoreceptor 10 was manufactured according to the following procedure.

First, an aluminum substrate having a thickness of 6 mm was used as the conductive substrate 11. On this substrate, an organic photosensitive layer 14 mainly composed of a phthalocyanine pigment, an aromatic amine and polycarbonate (binder resin) was formed. afterwards,
On the photosensitive layer 14, a surface release layer 17 was formed. As described later, when forming the surface release layer 17 on the photosensitive layer 14, the compatible layer
16 are formed simultaneously.

The procedure for forming the surface release layer 17 will be described below. First, the surface of the photosensitive layer 14 was washed with 2-propanol and dried by blowing high-pressure nitrogen gas. In the present embodiment, as the surface release layer material, (a) Tosgard 510 which is a silicone hard coating agent (manufactured by Toshiba Silicone)
, (B) XC98-B2472 which is a fluoroalkylsilane (manufactured by Toshiba Silicone), (c) amino-based silane coupling agent
A mixed material mainly composed of TSL8331 (γ-aminopropyltriethoxysilane, manufactured by Toshiba Silicone) was used. Specifically, 100 parts by weight of Tosgard 510 is added to X
20 parts by weight of C98-B2472, 50 parts by weight of 2-propanol, 17 parts by weight of TSL8331, and only 10 parts by weight of water were added to prepare a coating liquid by stirring and mixing. Then, a coating film was formed by dip coating using this coating liquid. The pulling speed during dip coating is 5 cm / min,
5 minutes after coating, air-dried in air at room temperature, 90
A heating effect was applied at 1 ° C. for 1 hour. The thickness of the cured surface release layer 17 was about 0.9 μm. In addition, this surface release layer 17
The surface energy was calculated by measuring the contact angle between water and a petroleum-based insulating solvent (Isopar L: manufactured by Exxon Chemical) having a known surface energy by a droplet method. As a result, the surface release layer 17 in the second embodiment is obtained.
Had a surface energy of about 22 dyn / cm.

With respect to the photoreceptor 29 manufactured by the above procedure,
The cross-sectional structure was observed using a TEM (transmission tunnel microscope). As a result, it was confirmed that the compatible layer 16 formed by the reaction between the surface release layer material and the photosensitive layer was formed to a thickness of about 30 nm between the surface release layer 17 and the photosensitive layer 14. Was done.

Further, with respect to the photoreceptor 10 in Example 2, the half-life exposure amount E _1/2 and the sensitivity S were measured as electrostatic characteristics. As a result, in this example, as shown in Table 2, E _1/2 = 0.40 (μJ / cm ² ) and sensitivity S = 2.5
(Cm ² / μJ).

Further, a visible image was formed on the photoreceptor 10 in the second embodiment using a liquid developer,
Heat / pressure transfer (offset transfer) was performed on an intermediate transfer member made of 6 dyn / cm urethane rubber. The heating temperature was 70 ° C. on both the intermediate transfer member side and the photosensitive member side. The pressure is the width of A4 paper (approximately 210 mm), including the weight of the intermediate transfer member.
The weight was 50 kg per unit. As a result, it was confirmed by weight measurement before and after transfer that a toner transfer efficiency of 99% was obtained as shown in Table 2.

In addition, the surface release layer 17 formed in this embodiment
Was subjected to a quantitative evaluation of durability. Specifically, after a solid image of 20 mm × 20 mm is developed on the photoreceptor 10 using a cyan toner, a Kimwipe (manufactured by Jujo Kimberly) is developed.
The operation of wiping using was repeated. At this time, each time the wiping operation was repeated, the contact angle of the surface release layer 17 with a petroleum-based insulating solvent (Isopor L: manufactured by Exxon Chemical) was measured using a droplet method. Then, the initial value Shitaint contact angle, the above operations to extract the contact angle theta ₂₀ at the time of repeated 20 times, the rate of change in contact angle with respect to the initial value _{θint θv = (θint -θ 20)} / θint × By calculating 100, the durability was quantitatively evaluated. At this time, θv
Is smaller, it is determined that the durability of the surface release layer is better. In this example, as shown in Table 2, θv was 12%.

Example 3 In Example 3, (a) Tosguard 51 which is a silicone hard coat agent was used as a component of the surface release layer material.
0 (manufactured by Toshiba Silicone), (b) XC98-B2472 which is a fluoroalkylsilane (manufactured by Toshiba Silicone), (c) amino-based silane coupling agent TSL8331 (γ-aminopropyltriethoxysilane, manufactured by Toshiba Silicone), (d ) Epoxy silane coupling agent TSL8350 (γ-glycidoxypropyltrimethoxysilane, manufactured by Toshiba Silicone), (e) Al
A mixed material mainly composed of chelating agent D (manufactured by Kawaken Fine Chemicals) was used.
20 parts by weight of XC98-B2472,
50 parts by weight of propanol, 8.5 parts by weight of TSL8331
8.5 parts by weight of TSL8350 and 0.85 of aluminum chelating agent
A photoreceptor 10 was prepared in the same manner as in Example 2, except that a coating solution containing only 10 parts by weight of water and 10 parts by weight of water was used.
The thickness of the cured surface release layer 17 was about 1.0 μm.
When the surface energy was calculated in the same manner as in Example 2, the surface energy of the surface release layer 17 in Example 3 was about 20 dyn / cm.

The photoconductor 10 of the third embodiment is also TEM
The cross-sectional structure of the photoreceptor was observed using a (transmission tunnel microscope). As a result, it was confirmed that the compatible layer 16 formed by the reaction between the surface release layer material and the photosensitive layer was formed to a thickness of about 50 nm between the surface release layer 17 and the photosensitive layer 14. Was done.

The photosensitive member 10 of the third embodiment also
When the half-life exposure amount E _1/2 and the sensitivity S were measured as electrostatic characteristics, as shown in Table 2, E _1/2 = 0.42 (μJ /
cm ² ) and sensitivity S = 2.4 (cm ² / μJ).

Further, under the same conditions as in Example 2, heat and pressure transfer (offset transfer) was performed on an intermediate transfer member made of urethane rubber having a surface energy of 36 dyn / cm.
It was confirmed that 100% toner transfer efficiency was obtained as shown in FIG.

In addition, in the same manner as in the second embodiment,
The durability of the surface release layer was evaluated. As a result, in this example, as shown in Table 2, θv was 9%. Comparative Example 4 In Comparative Example 4, as a component of the surface release layer material, 100 parts by weight of Tosgard 510 was added to XC98-B24.
Photoconductor 10 was prepared in the same manner as in Example 2, except that a coating solution containing 20 parts by weight of 72 and 50 parts by weight of 2-propanol was used. The film thickness of the surface release layer 17 after curing was about 1.1 μm.

When the surface energy was calculated in the same manner as in Example 2, the surface release layer in Comparative Example 4 was calculated.
The surface energy of 17 was about 21 dyn / cm. Also in Comparative Example 4, the cross-sectional structure of the photoconductor 10 was observed using a TEM (transmission tunnel microscope). As a result, also in Comparative Example 4, between the surface release layer 17 and the photosensitive layer 14,
Although there was a compatible layer 16 formed by the reaction between the surface release layer material and the photosensitive layer, it was confirmed that the layer was a very thin layer having a thickness of about 3 nm.

For the photoreceptor of Comparative Example 4, half-exposure exposure E _1/2 and sensitivity S were measured as electrostatic characteristics. As a result, as shown in Table 2, E _1/2 = 0.48 (μ
J / cm ² ) and sensitivity S = 2.1 (cm ² / μJ).

Further, under the same conditions as in Example 2, heat and pressure transfer (offset transfer) was performed on an intermediate transfer member made of urethane rubber having a surface energy of 36 dyn / cm.
It was confirmed that a toner transfer efficiency of 99% was obtained as shown in FIG.

In addition, in the same manner as in the second embodiment,
The durability of the surface release layer 17 was evaluated. As a result, in Comparative Example 4, as shown in Table 2, θv was 48%. Thus, when the comparative example 4 is compared with the examples 2 and 3, the electrostatic properties and the toner transferability of the photoreceptor are almost the same, but the durability of the surface release layer is remarkably high. The inferiority is that since the silane coupling agent and the Al chelating agent are not added to the surface release layer material, the compatible layer is very thin, the adhesion is reduced, and the cohesive force of the release layer itself is weak. It is thought to be caused by

Comparative Example 5 In Comparative Example 5, XC98-B24 was used as a component of the surface release layer material in an amount of 100 parts by weight of Tosguard 510.
Photoreceptor 10 was prepared in the same manner as in Example 2, except that a coating solution containing 20 parts by weight of 72, 50 parts by weight of 2-propanol and 10 parts by weight of xylene was used. The thickness of the cured surface release layer was about 0.8 μm. Further, when the surface energy was calculated in the same manner as in Example 2, the surface energy of the surface release layer in Example 3 was about 20%.
dyn / cm.

Also in Comparative Example 5, the cross-sectional structure of the photoreceptor 10 was observed using a TEM (transmission tunnel microscope). As a result, also in Comparative Example 5, the surface release layer 17
And the photosensitive layer 14, there is a compatible layer 16 formed by the reaction between the surface release layer material and the photosensitive layer, and has a thickness of about 200
nm.

The photosensitive member 10 of Comparative Example 5 also
The half-exposure amount E1 _{/ 2} and the sensitivity S were measured as electrostatic characteristics. As a result, as shown in Table 2, E _1/2 = 2.20 (μ
J / cm ² ), sensitivity S = 0.45 (cm ² / μJ),
A remarkable decrease in electrostatic characteristics was observed.

Further, under the same conditions as in Example 2, heat and pressure transfer (offset transfer) was performed on an intermediate transfer member made of urethane rubber having a surface energy of 36 dyn / cm.
It was confirmed that a toner transfer efficiency of 96% was obtained as shown in FIG.

In addition, in the same manner as in the second embodiment,
The durability of the surface release layer 17 was evaluated. As a result, in Comparative Example 5, as shown in Table 2, θv was 45%. As described above, when the comparative example 5 is compared with the examples 2 and 3, the toner transferability is slightly reduced, but the electrostatic property of the photoconductor is significantly reduced. It is considered that since xylene was added to the material, the underlying photosensitive layer was attacked. At first sight, the durability of the surface release layer is remarkably inferior because it seems that the compatibility layer itself is thick and thus the adhesion is improved. However, a silane coupling agent or Al It is considered that this is because the cohesive force of the release layer itself is weak because the chelating agent is not added.

[0072]

[Table 2]

Example 4 FIG. 4 shows the layer structure of a photoreceptor according to Example 4 of the present invention. Thus, the photoconductor 10 includes the substrate 11, the conductive elastic layer 12,
It comprises a barrier layer 13, a photosensitive layer 14, a compatible layer 16, and a surface release layer 17. The photoreceptor 10 was manufactured according to the following procedure. First, an aluminum substrate having a thickness of 6 mm was used as the substrate 11. This board
A conductive urethane rubber sheet having a thickness of 0.2 mm and a JIA hardness of 40 degrees was adhered on the substrate 11 via a conductive adhesive.
Here, a conductive urethane rubber sheet having a volume resistivity of 10 ⁷ Ω · cm was produced by dispersing carbon fine particles in urethane rubber. As the barrier layer 52, an Al deposited film having a thickness of 200 nm was formed by an electron beam deposition method.
Then, in order to form an organic photosensitive layer mainly containing a phthalocyanine pigment, an aromatic amine, and a polycarbonate (binder resin), these components were added to THF.
A coating solution dissolved in (tetrahydrofuran) was prepared, and a film was formed by a dip coating method. And 1
After air-drying for 0 minutes, heat treatment was performed at 90 ° C. for 1 hour to form an organic photosensitive layer 14 (about 20 μm thick).

Thereafter, a surface release layer 17 was formed on the photosensitive layer 14. As described later, when the surface release layer 17 is formed on the photosensitive layer 14, the compatible layer 16 is simultaneously formed. Surface release layer
The procedure for forming 17 is described below. First, the surface of the photosensitive layer 14 is
-Washed with propanol and dried by blowing high pressure nitrogen gas. In this embodiment, as the surface release layer material, (a) Tosgard 510 (manufactured by Toshiba Silicone) which is a silicone hard coating agent, (b) XC98-B2472 (manufactured by Toshiba Silicone) which is a fluoroalkylsilane, (c)
Amino-based silane coupling agent TSL8331 (γ-aminopropyltriethoxysilane, manufactured by Toshiba Silicone), (d) epoxy-based silane coupling agent TSL8350 (γ-glycidoxypropyltrimethoxysilane, manufactured by Toshiba Silicone),
(e) A mixed material mainly composed of an Al chelating agent D (manufactured by Kawaken Fine Chemicals) was used. Specifically, for 100 parts by weight of Tosgard 510, 20 parts by weight of XC98-B2472, 50 parts by weight of 2-propanol and 8.5 parts by weight of TSL8331.
A coating liquid was prepared by adding 8.5 parts by weight of TSL8350, 0.85 parts by weight of an aluminum chelating agent, and 10 parts by weight of water. Then, a coating film was formed by dip coating using this coating liquid. The pulling speed at the time of dip coating was 5 cm / min. After air-drying in a room temperature air atmosphere for 5 minutes after coating, a heating effect was applied at 90 ° C. for 1 hour.
The thickness of the cured surface release layer 17 was about 1.0 μm.
The surface energy of the surface release layer 17 was calculated by measuring the contact angle between water and a petroleum-based insulating solvent Isopar L (manufactured by Exxon Chemical) having a known surface energy by a droplet method. As a result, Example 4
The surface energy of the surface release layer was about 20 dyn / cm.

With respect to the photoreceptor 10 manufactured by the above procedure,
The cross-sectional structure was observed using a TEM (transmission tunnel microscope). As a result, it was confirmed that the compatible layer 16 formed by the reaction between the surface release layer material and the photosensitive layer was formed to a thickness of about 50 nm between the surface release layer 17 and the photosensitive layer 14. Was done.

Further, a visible image was formed on the photoreceptor 10 in the fourth embodiment by using a liquid developer,
Heat transfer to an intermediate transfer body made of urethane rubber of 6 dyn / cm
Pressure transfer (offset transfer) was performed. The heating temperature was 70 ° C. on both the intermediate transfer member side and the photosensitive member side. The pressure is adjusted to the width of A4 paper (about 210 m
m) was applied at a weight of 50 kg. As a result, 100% toner transfer efficiency was obtained as shown in Table 3.
It was confirmed by weight measurement before and after transfer.

Further, the surface release layer 17 formed in the fourth embodiment
Was subjected to a quantitative evaluation of durability. Specifically, after a solid image of 20 mm × 20 mm was developed on a photoreceptor using a cyan toner, an operation of wiping using a Kimwipe (manufactured by Jujo Kimberly) was repeated. At this time, every time the wiping operation is repeated, the petroleum insulating solvent (Isoper L:
The contact angle of the surface release layer 17 with respect to Exxon Chemical Co., Ltd.) was measured using a droplet method. Then, the initial value of the contact angle θint
And the contact angle θ ₂₀ when the above operation is repeated 20 times
And the rate of change of the contact angle to the initial value θint θ
v = by calculating _{(θint -θ 20) / θint ×} 100, was quantitative evaluation of durability. At this time, it is determined that the smaller the value of θv, the better the durability of the surface release layer. In the fourth embodiment, as shown in Table 3, θ
v was 10%.

Comparative Example 6 In Comparative Example 6, XC98-B24 was used as a component of the surface release layer material in an amount of 100 parts by weight of Tosguard 510.
Photoreceptor 10 was prepared in the same manner as in Example 4, except that a coating solution containing only 20 parts by weight of 72 and 50 parts by weight of 2-propanol was used. The thickness of the cured surface release layer was about 1.1 μm. Further, when the surface energy was calculated in the same manner as in Example 4, the surface energy of the surface release layer in Comparative Example 6 was about 21 dyn / cm.

Also in Comparative Example 6, the cross-sectional structure of the photoreceptor 10 was observed using a TEM (transmission tunnel microscope). As a result, also in Comparative Example 6, the surface release layer 17
A compatible layer 16 formed by the reaction between the surface release layer material and the photosensitive layer exists between the photosensitive layer 14 and the photosensitive layer 14, and the thickness thereof is about 3 mm.
It was confirmed that the layer was as thin as nm.

Further, under the same conditions as in Example 4, heat and pressure transfer (offset transfer) was performed on an intermediate transfer member made of urethane rubber having a surface energy of 36 dyn / cm.
It was confirmed that a toner transfer efficiency of 99% was obtained as shown in FIG.

The durability of the surface release layer 17 was evaluated in the same manner as in Example 4. As a result, in Comparative Example 6, as shown in Table 3, it was confirmed that θv was 65% and the durability was significantly reduced.

As described above, when Comparative Example 6 was compared with Example 4, the toner transferability was almost the same, but the durability of the surface release layer was extremely poor. It is considered that since the silane coupling agent and the Al chelating agent were not added to the material, the compatible layer was extremely thin, the adhesion was reduced, and the cohesive force of the release layer itself was weak. Furthermore, since the elastic layer is present on the base, the adhesion is more likely to be reduced, and the rupture stress applied to the release layer itself is also considered to be the main cause of the decrease in the durability of the surface release layer.

[0083]

[Table 3]

In the above embodiments, the case of wet electrophotography has been described, but it is apparent that the same effect can be obtained in dry electrophotography. In particular, the present invention is very effective when heat and pressure are transferred by melting a dry toner by heat.

[0085]

As described above, according to the present invention,
By interposing a barrier layer having an appropriate thickness between the elastic layer of the photoreceptor and the photosensitive layer, toner transferability and image quality can be improved. Further, by forming a compatible layer having an appropriate thickness between the surface release layer and the photosensitive layer of the photosensitive member, the durability of the photosensitive member can be improved. Accordingly, it is possible to provide an electrophotographic photoreceptor that is highly reliable and capable of forming a high-quality image and an electrophotographic apparatus using the same.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of a photosensitive member according to the embodiment of the present invention.

FIG. 3 is a sectional view of a photoreceptor according to another embodiment of the present invention.

FIG. 4 is a sectional view of a photosensitive member according to another embodiment of the present invention.

FIG. 5 is a sectional view of a photosensitive member according to a comparative example.

[Explanation of symbols]

 1, 10 photosensitive member 2 charger 3 exposure beam 4 developing device 5 transfer device 6 intermediate transfer member 7 pressure roller 8 Cleaner 9 ... Paper 11 ... Substrate 12 ... Elastic layer 13 ... Barrier layer 14 ... Photosensitive layer 16 ... Compatible layer 17 ... Surface release layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H068 AA02 AA03 AA04 AA08 AA10 AA43 AA48 AA50 BA58 BB29 BB31 BB33 FB11 FC08 2H069 BA01 EA02 2H074 AA03 AA06 AA09 BB31 EE07

Claims (7)

[Claims] An elastic layer, and an elastic layer formed on the surface of the elastic layer.
An electrophotographic photosensitive member comprising: a barrier layer having a thickness of 0 nm or more and 30 μm or less; and a photosensitive layer formed on the surface of the barrier layer. 2. A photoconductor, a latent image forming means for forming an electrostatic latent image on the photoconductor, a developing means for supplying a liquid developer to the electrostatic latent image to visualize the electrostatic latent image, Pressed against the photoreceptor,
An electrophotographic apparatus comprising: a transfer unit configured to transfer a visible image formed on the photosensitive member; wherein the photosensitive member includes an elastic layer and a barrier having a thickness of 10 nm or more and 30 μm or less formed on the surface of the elastic layer. An electrophotographic apparatus comprising a layer and a photosensitive layer formed on the surface of the barrier layer. 3. An electrophotographic photoreceptor comprising: a photosensitive layer; and a release layer formed on the photosensitive layer and containing a release component and a compatible component. 4. An elastic layer and a first layer formed on the surface of the elastic layer.
4. The electrophotographic photoreceptor according to claim 3, wherein the barrier layer has a thickness of 0 nm or more and 30 [mu] m or less, and the photosensitive layer is formed on the surface of the barrier layer. 5. The method according to claim 1, wherein an interface between the photosensitive layer and the release layer has a compatible layer containing a release layer component and a photosensitive layer component and having a thickness of 5 nm or more and 100 nm or less. Item 3
The electrophotographic photosensitive member according to the above. 6. The electrophotographic photosensitive member according to claim 3, wherein said release component is a silane coupling agent. 7. A photoconductor, a latent image forming means for forming an electrostatic latent image on the photoconductor, a developing means for supplying a liquid developer to the electrostatic latent image to visualize the electrostatic latent image, Pressed against the photoreceptor,
An electrophotographic apparatus comprising: a transfer unit that transfers a visible image formed on the photoconductor. The photoconductor includes a photosensitive layer and a release component and a compatible component formed on the photosensitive layer. An electrophotographic apparatus comprising: a release layer containing the same.