JPS59159171A - Image bearing material - Google Patents

Abstract

PURPOSE:To enhance strength, especially, impact strength by forming the insulating layer of a toner image bearing material consisting of the upper layer composed essentially of an org. solvent-soluble thermoplastic resin and the lower layer composed essentially of a curable type resin and a specified org. solvent- soluble thermoplastic resin. CONSTITUTION:An insulating layer formed on a photoconductive layer or on an electrostatic image or tone image bearing material having no photoconductive layer consists of the 2-layer structure. The upper layer is composed essentially of one selected from various kinds of org. solvent-soluble thermoplastic resins to enhance characteristics, such as durability, cleanability, and electrostatic charge retentivity. The lower layer is composed essentially of an org. solvent- soluble thermoplastic styrene-acrylonitrile copolymer rein having 10,000-150,000 weight average mol. wt. and 90-120 deg.C softening point, and a curable type resin, optionally of photo- or thermosetting resin, in a curable type resin/copolymer type resin mixing weight ratio of (90:10)-(40:60). The image bearing material thus obtained is raised in mechanical strength and adhesion between the layers and enhanced in durability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image holding member for holding an entire electrostatic image or toner image.

Electrostatic or toner images are formed by a gentle process. Image holding members on which electrostatic images or toner images are formed include those having a photoconductive layer and those without a photoconductive layer, which are called electrophotographic photoreceptors.

An image-bearing member usually consists of a support and an image-bearing layer thereon.

Electrophotographic photoreceptors have various configurations in order to obtain predetermined characteristics or depending on the type of electrophotographic process to which they are applied. Typical electrophotographic photoreceptors include a photoreceptor in which a photoconductive layer is formed as an image-retaining layer on a support, and a photoreceptor in which a photoconductive layer is laminated as an image-retaining layer and an insulating layer thereon. Ashi is widely used. A photoreceptor composed of a support and a photoconductive layer is used for image formation by most common electrophotographic processes, ie, charging, image exposure and development, and optionally transfer. In addition, for photoreceptors with an insulating layer gold biased, this insulating layer can be used to improve the photoconductive layer, improve the mechanical strength of the photoreceptor, improve dark decay characteristics, or be applied to certain electrophotographic processes, etc. It is established for a purpose. Typical examples of photoreceptor plates having such an insulating layer or electrophotography using a photoreceptor with an insulating layer all over the insulating layer are, for example, U.S. Pat. Publication No. 38-15446, Special Publication No. 46-371
Publication No. 3, Special Publication No. 42-23910, Special Publication No. 43
-24748 Publication, Special Publication No. 42-19747,
It is described in Japanese Patent Publication No. 36-4121.

A predetermined electrophotographic process is applied to the electrophotographic photoreceptor to form an electrostatic image, and this electrostatic image is developed and
Visualized swelling.

A typical configuration of an image bearing member without a photoconductive layer is one having an insulating layer as an image bearing layer, and some typical uses of this image bearing member are described below.

(1) For example, Tokuko Publication No. 32-7115, Tokuko Publication No. 3
As described in Japanese Patent Publication No. 2-8204 and Japanese Patent Publication No. 43-1559, the entire electrostatic image photoconductive layer formed on an electrophotographic photoreceptor is The toner image is transferred to an unsupported image holding member and developed, and then the toner image is transferred to a recording medium. An image holding member used in this electrophotographic process.

(2) In addition, as another electrophotographic process in which an electrostatic image is formed on an image holding portion I that does not have a photoconductive layer in correspondence with an electrostatic image formed on an electrophotographic photoreceptor, for example, 30320, Japanese Patent Publication No. 48-5063, Japanese Patent Application Publication No. 1973. As described in Publication No. 341, an electrostatic image is completely formed on a screen-like electrophotographic photoreceptor having many minute openings by a predetermined electrophotographic process, and the entire electrostatic image is exposed to light. By performing corona charging treatment on the image holding part opening which does not have a conductive layer, the ion flow of the corona is modulated and an electrostatic image is formed on the image holding part opening which does not have a photoconductive layer, and this is completely developed with toner. An example of this process is to transfer the image onto a recording medium to form a final image. Image holder opening used in this electrophotographic process.

(3) Also, according to other electrophotographic processes, 10
゜Photographic photoreceptor or image holding part I without photoconductive layer
The toner image formed on the toner image is not directly transferred to a recording medium, but is further transferred to an image holding part Io that does not have a photoconductive layer.
Next, the toner image is transferred from this image holding member to a recording medium and fixed. An image holding member used in this electrophotographic process. This process is particularly useful for forming color images or for high speed copying. Recording media are usually highly flexible, such as paper or film, and for this reason, it is possible to accurately transfer a three-color image to a recording media with less deformation than when placing the image on a stand. A more accurately aligned color image is formed by transferring the three-color images to an image holding member which can be made of a suitable material, and then transferring the three-color images to a recording medium in the t-period. Furthermore, it is effective for speeding up copying that the toner image is transferred to the recording medium via the image holding member.

(4) In addition, as another process, an electrical signal is applied to a multi-needle electrode to coat the surface of the image holding part without the photoconductive layer.
It is capable of forming an electrostatic image in response to an electrical signal and developing it into an image.

The image holding part opening used in electrophotography is subjected to corona charging treatment,
Whole bones are easily damaged because they are subjected to various electrical and mechanical shocks during development processing, cleaning processing, and the like. Once the image holding member is damaged, the quality of the image formed will be significantly reduced. Therefore, there is a strong desire for an image holding member that has excellent ff1l electrical and mechanical impact resistance, charge retention, and the like. However, it has not been easy to provide an image holding member having such excellent characteristics.

For this reason, conventionally, the insulating layer has a three-layer structure, with the upper layer having good properties in terms of durability, cleanability, and charge retention on the surface of the insulating layer, and the lower layer using a curable resin with high mechanical strength. It completely prevents indentation of the photoconductive layer due to mechanical impact and maintains hφ. Further, it has been proposed that the intermediate layer has the function of an adhesive layer that adheres the upper layer and the lower layer, and that the intermediate layer functions as one insulating layer as a whole.

[7]However, when this method is used, the production process is complicated, which increases the burden on production management and production equipment, resulting in high costs.

As the number of processes increases, the rate of defective products increases significantly.

Due to the large number of bonded parts, there is a high risk of peeling when a mechanical S shock is applied. There are drawbacks such as:

The present invention has performance equivalent to or better than the three-layer image holding member described above in terms of durability, and is capable of forming an upper layer of the image holding member, which is a problem in terms of production equipment, management, cost, and productivity. Make it the main purpose.

The present invention provides an image holding member that holds both an electrostatic image and a toner image, and includes an upper layer mainly composed of an organic solvent-soluble thermoplastic resin and a curable resin on the surface of the image holding part '4'OA. and a lower layer consisting entirely of an organic solvent-soluble thermoplastic resin, and the organic solvent-soluble resin used in the lower layer is a styrene-acrylonitrile copolymer resin. It is a member.

The upper layer constituting the entire insulating layer of the image holding member according to the present invention is:
An organic solvent-soluble thermoplastic resin with excellent surface wettability, mold releasability,
It has excellent moisture resistance, and achieves good strength characteristics in terms of durability, cleanability, and charge retention on the surface of the insulating layer. In addition, the lower layer of the insulating layer is made of a curable resin and a styrene-acrylonitrile copolymer, and the curable resin component increases the mechanical strength of the entire insulating layer, particularly preventing indentations in the photoconductive layer caused by mechanical impact. Then, preserve the entire photoconductive layer.

Also, the presence of the styrene-acrylon copolymer resin has the effect of completely strengthening the adhesion with the upper layer of the image holding member and integrating it. have If the styrene-acrylonitrile copolymer resin is not present, the adhesive strength between the upper layer and the lower layer is insufficient, resulting in delamination between the two layers, which may affect the durability of the photoreceptor. j4 However, the presence of the styrene-acrylonitrile copolymer resin solves the problem of poor adhesive strengthtb.The features of each resin used in the upper and lower layers improve the durability of the photoreceptor. contribute effectively to

The thermoplastic resin used for the upper layer of the image holding member includes:
Examples include polyester, phenoxy, polystyrene, vinyl chloride, cellulose, vinyl acetate, vinyl chloride/vinyl acetate copolymer, polyacrylate polyolefin, vinyl acetate/acrylic copolymer, thermoplastic urethane, and the like.

It is also effective to contain a lubricant and, if necessary, a surfactant for dispersing the lubricant in the upper layer in order to further improve the surface lubricity.

If a lubricant is used, a powder having a lubricating action (4♀) is appropriately used. Typical lubricants include polyethylene, polytetrafluoroethylene, polyethylene terephthalate,
Examples include those substantially insoluble in common solvents, such as polyvinylidene fluoride, polyvinyl chloride, metal stearate, graphine wax, and talc. The particle size of the lubricant is
A particle size of 10 μm or less, particularly 5 μm or less is preferable. The amount of lubricant added is appropriately set, but it is usually 0.5 to 90% by weight, particularly preferably 5 to 50% by weight.

Various types of surfactants may be used, but
Particularly effective are fluorosurfactants. A fluorine-based surfactant is a surfactant containing a highly fluorinated long-chain alkyl group in its molecular shell. Typical fluorosurfactants include C3F17SO2・NRCH2COOKC6F17S0
2'NRCH2CH20(CH2CH20)nH(n-
5,10,15)C3F17SO2N(CH2CH20
H20H)2CBF 17RO(CH2CH20)nc
16F34(RO)n n -5~20C46F34
(R-0)nRn -5 to 20, etc.

R represents an alkyl group such as methyl, ethyl, propyl, butyl, or an allyl group such as phenyl or naphthyl.

The fluorosurfactant is preferably contained in a range of 0.5 to 50% by weight, particularly 1 to 30% by weight. The thickness of the upper layer is appropriately set, but it is usually in the range of 40 to 2 μm, and preferably in the range of 20 to 4 μm.

The curable resin forming the lower layer is a resin that is cured by heat photoelectron beam or the like. In the case of thermosetting resins, it is possible to fully cure them at room temperature depending on the type of resin. Particularly suitable hardened resins include acrylic resins, urethane resins, polyester resins, epoxy resins, melamine resins, and silicone resins.

The styrene-acrylonitrile copolymer resin that forms the lower layer is a copolymer of styrene C6■■5C2H3 and acrylonitrile CH2CHCN, and has very low mechanical strength, and even when mixed with a curable resin, its strength decreases. Since it is relatively small and flexible despite its high hardness, defects such as cracks in the insulating layer due to stress strain are less likely to occur.

The used i% snalene-acrylonitrile copolymer resin has an average molecular weight of 10,000 to 150,000 and a softening point of 90°C to 12
The temperature is in the range of 0°C, and the preferred mixing ratio of the curable resin and styrene-acrylonitrile copolymer resin is 90:1.
0-40:60, especially 70:30-50:
A range of 50 is appropriate.

The thickness of the lower layer is appropriately set, but it is usually suitably set in the range of 5 to 40 microns, particularly 10 to 25 microns.

When the image holding member is an electrophotographic photoreceptor, the most typical structure is a laminate in which the photoconductive layer is between a support and an insulating layer. The support is formed from any material such as a metal plate such as stainless steel, copper, aluminum, or tin, paper, or a resin film. The support may be omitted if necessary.

The photoconductive layer is made of S, Se, PbO, and S,
So.

It is formed by full vacuum deposition of an inorganic light guide material such as an alloy or an intermetallic compound containing Tor As + Sb or the like. In addition, when using the sputtering method, ZnO, CdS, C
dSe.

A photoconductive layer can also be formed by attaching a high melting point photoconductive material such as 'rio2 to the support. In addition, when forming a photoconductive layer by coating, photoconductive materials such as polyvinylcarbazole, anthra7ane, phthalocyanine, dye-sensitized or Lewis acid-sensitized products, and insulating binders of these materials can be used. A mixture with? Can be used. Cut Zn
Mixtures of inorganic photoconductors such as O, CdS, TiO2, PbO with insulating binders are also suitable. Note that various resins are used as the insulating binder. The thickness of the photoconductive layer depends on the type and characteristics of the photoconductive substance used, but is generally about 5 to 100 microns, particularly about 10 to 50 microns. The most typical structure when the folded image holding member does not have a photoconductive layer is one in which an insulating layer is formed on a support.

Generally, when an insulating layer is attached to the entire image holding member with the main purpose of protecting the image holding member, improving its durability, and improving the dark/shark characteristics, the insulating layer is set to be relatively thin, and the insulating layer is set to be relatively thin.
The insulating layer provided in the case of use in a hemostatic process is set relatively thick.

Usually, the thickness of the insulating layer is 5 to 70μ, particularly 10 to 70μ.
It is set to 50μ.

Implementation 19-1 12 parts of vinyl chloride-vinyl acetate copolymer resin (trade name: VMCH, manufactured by Union Carbide) was added as a binder to 100 parts (parts by weight, same hereinafter) of CdS powder, and then methyl ethyl ketone was completely added. After stirring well,
Passed 5 times through a roll mill with a 40μ gap
Mix S and the binder well, then adjust the viscosity to 500 centipoise using methyl ethyl ketone, and
An n-long drum-ring shaped support is immersed in this conditioning solution,
After pulling up at a rate of 50 mm/ml, drying was performed at a temperature of 80° C. for 20 minutes to form a photoconductive layer with a thickness of 35 μm. Furthermore, this was coated by dip coating with a solution of cyclized butadiene rubber (trade name: CBR-M, made by Nippon Gosei Rubber Co., Ltd.) dissolved in cyclohexane and adjusted to a viscosity of 40 centiboise, and dried at 80°C for 20 minutes to obtain a film thickness of 7 μm. A layer is formed to serve as a sealing layer.

Next, on top of this, a photocurable acrylic ester resin (trade name: Aronidisuf 100. manufactured by Toagosei Chemical Co., Ltd.) and an organic solvent-soluble thermoplastic styrene-acrylonitrile resin (
Product name Tyril 769 (manufactured by Asahi Dow) and r60:40
of Ml and volume ratio, add photoinitiator, add 2 parts of ethyl anthraquinone, and add 6 parts of methyl ethyl ketone.
Dip-coat with 5 cm voids and heat at 80°C for 15 cm.
After drying for a minute to remove residual solvent, it was cured using an 8 kW ultraviolet high-pressure mercury lamp to form a film with a thickness of 18 μm, which served as the lower layer. Furthermore, a powder of polytetrafluoroethylene (trade name Nilpronto-2, manufactured by Daigin Industries) was added as a lubricant to a methyl ethyl ketone solution of vinyl chloride-vinyl acetate copolymer resin (trade name - VMCF (manufactured by Union Carbide)). -Next paddy diameter 03μm) Using a surfactant (trade name: Florado FC431, manufactured by Sumitomo 3M), 7μm using a coating solution dispersed in a ball mill pot.
A coating film with a thickness of m is formed by a dipping method and dried at 80° C. for 15 minutes to form the upper layer. The photoreceptor thus manufactured is made into a photoreceptor.

The lower layer was made of photocurable resin (product name: Aronix 7100; Toagosei Kagaku 1A).
The photoconductor B is made entirely of photoconductors (manufactured by TOKYO).

In addition, in photoconductor B, a styrene-acrylonitrile copolymer resin (trade name: Titsur 769, manufactured by Asahi Dow) and a photocurable acrylic acid ester resin (trade name: Aronix 7100° Toagosei Co., Ltd.) are placed between the upper layer and the lower layer. An intermediate layer made of
This is referred to as photoreceptor C.

For these photoreceptors A to C, the entire electrophotographic process consisting of - (l) C charging, secondary DC static neutralization and simultaneous exposure, full-surface irradiation, (dry development with toner, and cleaning treatment with a urethane rubber cleaning blade) was carried out. ) and compared the durability.

The results showed that in Photoreceptor A, the photoreceptor insulating layer did not peel off even after the electrophotographic process was repeated 100,000 times, and the images obtained were clear.

In photoreceptor B, after 8,000 repetitions of the electrophotographic process, the upper layer of the insulating layer partially peeled off, and problems such as toner sticking and grade damage occurred in the 7th part, resulting in poor images. It became complete.

Regarding photoconductor C, even after 100,000 repetitions of grooves in the electrophotographic process, no abnormality was found on the photoconductor and the images obtained were clear, and when compared with photoconductor A, there is no difference between the two. Q I wanted to see Example 2 Photoreceptors A' to C' were manufactured by using a 5s-Te photoconductive layer in place of the CdS photoconductive layer in the photoconductors A to C of Example 1.

These photoreceptors A' to C' were also found to have the same durability as photoreceptors A to E.

Furthermore, S e - T e light? J4. The electric layer is 5 nine 5e
-Te (10wt) alloy 200g total evaporation solid layer weighed, evaporation source temperature e320℃, substrate (At'/linder)
Vapor deposition was carried out for 40 minutes at a temperature of 68° C. and an internal vacuum of I x 10-5 torr to form a film with a thickness of 65 μm.

Example 3 A photoreceptor was manufactured by forming an insulating layer having the following composition on top of the photovoltaic layer manufactured in Example 1, and the same results as in Example 1 were obtained.

Upper layer: Linear saturated polyester resin (Product name: Byron 200 manufactured by Toyobo) Polyethylene (2 μm diameter) as a lubricant Curing resin in the lower layer Photo-curing acrylic modification? Kishi resin (product name, Unidic V5501: Inu Nippon Ink)
Example 4 Cylindrical At drum base (220mmφX 500rr
rm), 45 parts by weight of a solvent-soluble styrene-acrylonitrile copolymer resin (product name: Esterene AS; manufactured by Nippon Steel Chemical ■) and a photocurable acrylic resin (product name:
TA-7-1 (manufactured by Toa Paint) was mixed, diluted with methyl ethyl ketone to a viscosity of υ150 centipoise, applied by dip coating, dried at a temperature of 80°C for 15 minutes, and then exposed to an 8 kW high-pressure ultraviolet mercury run ff1. A coating film with a thickness of 23 μm was formed by irradiation for minutes, and this was used as the lower layer. At this point, the photocurable resin has hardened, so is this lower layer as a whole resistant to solvents? have. Therefore, even if the entire upper layer is formed on this layer by the dipping method, it will not be attacked.

Next, add +4 to the thermoplastic resin (product name: Cordel Polysulfone; manufactured by Nissan Chemical) as a lubricant. Litetrafluoroethylene (trade name, Lubron Roux 2; manufactured by Daikin Industries, Ltd.) and surfactant (trade name: Florado F
C430: Manufactured by Sumitomo 3M) Full weight ratio 100:20
:3 to form a methyl ethyl ketone solution, dispersed in a ball mill, applied by dip coating, and dried at 80° C. for 15 minutes to form a 9 μm thick film as the upper layer.

Using this image holding part, an electrostatic image is formed on the CdS screen photoreceptor by modulating the corona discharge due to the electrostatic image formed on the CdS screen photoreceptor. In the forming process, ■Dry developer and urethane cleaning blade (hardness 70, angle 30° to the surface insulation layer of the sample, blade pressure 2.0 kg)
As a result of durability tests of development, transfer, and cleaning using K, the friction coefficient was 0.90, the number of image holding parts rotated smoothly, and the images were good. Even after 100,000 sheets were used, no abrasion or damage to the plaid edge portion, no friction scratches on the lunar surface of the image holding portion, and no delamination development of the insulating layer was observed. Furthermore, since only two layers of coating film were to be formed, the process was advantageous in terms of productivity.

Claims (1)

[Scope of Claims] 1. An image holding member that holds an electrostatic image or a toner image, consisting of a two-part layer consisting mainly of an excitation solvent-soluble thermoplastic resin, a curable resin, and an organic solvent-soluble thermoplastic resin. An image holding member characterized by comprising an insulating layer with a lower layer made entirely of styrene-acrylonitol copolymer resin. 2 Organic solvent-soluble styrene-acrylonitrile copolymer resin has a weight average molecular weight of 10,000 to 150,000 and a softening point of 90°C to
The mixing ratio of the curable resin and the styrene-acrylonitrile copolymer resin is 90:1.
The image holding member according to claim 1, which has a ratio of 0 to 40:60. 3. The image holding member according to claim 1, wherein the insulating layer is on the photoconductive layer. 4. The image holding member according to claim 1, further comprising a blocking layer between the light guiding acid layer and the blocking layer.