JPS60263956A - Developing method of electrostatic image - Google Patents

Abstract

PURPOSE:To improve the repetitive use durability of a photoconductive sensitive body having an adequately roughened surface by using a developer contg. silica having 40-100mmu average grain size of primary particles to develop the electrostatic image formed on the photosensitive body. CONSTITUTION:The photosensitive body consists of a photoconductive semiconductor contg. selenium on a conductive base body and the surface thereof is formed to 0.1-0.2mum roughness in the width of ruggedness. A toner added with the silica having 20-100mmu average grain size of the primary particles is used for the developer. The electrostatic image formed on the above-mentioned photosensitive body is developed by using the developer prepd. in such a manner. The recesses on the surface of the photosensitive body are thus prevented from being embedded by the silica particles. The recesses and projecting parts wear uniformly and even after the repetitive use, the rough surface condition is maintained. The transferability, transfer separability and cleaning property of the toner are satisfactorily maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing method for developing an electrostatic image formed on, for example, a selenium-based photoreceptor by electrophotography or the like with toner.

[Prior art]

A photoreceptor is used to record materials using electrophotography, etc.
The electrostatic image formed on the photoreceptor is generally developed with a fine powder toner made of paint resin and a colorant as -L, and then a transfer material such as paper is brought into contact with the photoreceptor surface to transfer the toner image. The transfer material is attracted to the surface of the photoreceptor by electrostatic force. In order to separate this, methods are used to neutralize the charge by applying corona discharge from the back side of the adsorbed transfer material, or to mechanically separate it by installing a separation claw, but the separation is not successful. If this is not done, the transfer material may wrap around the photoreceptor and cause a malfunction.

In addition, after copying, the toner remaining on the surface of the photoconductor is removed by cleaning means such as a blade for reuse.
If cleaning is incomplete and toner remains, it will be transferred to the next recorded material, creating an unnecessary image, so it is necessary to completely remove the toner.

The surface of the photoreceptor is usually finished with a mirror finish, but the mirror-like surface has the advantage of improving the quality of recorded images, etc.
The adhesion force with the toner is large, resulting in poor transfer of the toner to the transfer device, poor separation of the transfer material, and incomplete cleaning.

In order to solve these problems, Japanese Patent Application Publication No. 58-17495
Japanese Patent No. 8 proposes a method for manufacturing a photoreceptor in which a selenium-arsenic alloy is deposited on a conductive substrate whose surface has been appropriately roughened. A method of imparting appropriate roughness to the surface of a photoreceptor is effective in solving the above problem, especially in the case of photoreceptors containing selenium, but such photoreceptors become rough due to repeated use. This had the disadvantage that the desired effect was lost.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for developing an electrostatic image in which separation and cleaning properties of a transfer material on the surface of a photoreceptor do not deteriorate even after repeated use.

[Structure of the invention]

The above purpose is to improve the electrostatic image formed on the photoreceptor with a moderately rough surface, so that the average $+7 diameter of the -order particles is 40 to 10.
This was achieved by a developing method characterized by developing using a developer containing 0IIlpL silica.

As a result of studies conducted by the present inventors, it has been found that the decrease in surface roughening effect due to repeated use is related to the silica contained in the developer as an agent for toner fluidity.

In other words, the selenium-based photoreceptor is relatively soft, so it gradually wears out due to friction with the toner that forms the magnetic brush during development, but if fine silica particles are present at this time, the photoreceptor surface will become depressed. It is thought that as a result of being buried in silica particles, only the exposed convex portions are worn, the surface becomes smooth, and the roughening effect is lost. Silica usually consists of coarse secondary particles of about 100 mg, which are made up of a large number of fine secondary particles of about 10 to 20 particles, and are added to the toner as is, but the aggregation of silica particles occurs on the surface. This is due to relatively weak hydrogen bonding between silanol groups=SiOH, and is easily separated during development, filling all four parts of the surface of the photoreceptor.

As a result of conducting research focusing on the primary particle size of silica, the present inventor found that good results in the durability of the photoreceptor could be obtained by using silica with an average primary particle size of 40 to 100 mg. This led to the invention.

That is, in the present invention, by using silica made of relatively large primary particles as the silica added to the toner, the four parts of the surface of the photoreceptor are prevented from being filled with silica particles, and the four convex parts are uniformly worn. The rough surface condition is maintained even after repeated use, and the effects of improving toner transferability, transfer material separation, and cleaning performance are maintained. Therefore, if the average particle diameter of -order particles is 40n+p or less, there is no such result, and if the average particle size is N
Coarse silica of 10 Omg or more is undesirable because it has a low effect on the fluidity of the toner, which is the original objective.

The average particle diameter referred to herein is the average projected diameter of particles measured on the screen of an electron microscope photograph.

The photoreceptor used in the method of the present invention is a conductive substrate on which a photosensitive layer with a moderately roughened surface is formed from a photoconductive semiconductor containing selenium such as selenium, selenium-tellurium, selenium-arsenic, etc. .

A photoreceptor with a roughened surface can be obtained by depositing a photosensitive layer containing selenium on a conductive substrate that has been roughened in advance, or by puff polishing the surface of a smooth vapor-deposited layer. The surface roughness is preferably 0.1 to 0.2 gm in terms of the width of the unevenness.

The developer used in the method of the present invention may be either a so-called one-component developer consisting of a magnetic toner or a so-called two-component developer consisting of a toner and a magnetic carrier. Additives etc. depend on the fluidity of the toner.1. Except for silica, which is added as an agent, all materials manufactured using known materials, compositions, and manufacturing methods can be used.

That is, the toner is a polymer or copolymer of polymerizable monomers such as acrylic ester, methacrylic ester, styrene, various vinyl monomers, binder resin such as polyester resin, polyamide resin, or polyurethane resin, carbon black, organic or inorganic. Coloring agents such as various pigments, and if necessary, charge control agents such as nigrosine, low-molecular polyolefins, mold release agents such as wax, magnetite, magnetic materials such as Kasa, etc. are added, melted, kneaded, and cooled. It can be obtained by pulverization and classification, or by dispersing colorants and other materials in the polymerizable monomer, suspending it in an aqueous medium, and polymerizing it. Iron, ferrite, magnetite can be used as the magnetic carrier. It is possible to use ferromagnetic powder such as ferromagnetic powder, or an insulating knife or spear 7 in which the surface of the ferromagnetic particles is coated with MA fat or the like.

The silica according to the present invention can be easily added and mixed with the toner obtained as described above, and the added fil is 0.5 per 100 parts by weight of ζ inder resin contained in the toner.
A range of 1 to 1 part by weight is preferable. Silica may be untreated as long as its primary particles have an average diameter of 40 to 100 mμ, or it may be chemically treated without being limited thereto.

The method of the present invention will be specifically explained below with reference to Examples, but the embodiments of the present invention are not limited thereto.

Example 1 Styrene-acrylic resin, /Imer SDM73 (manufactured by San-Y Kasei Kogyo Co., Ltd.) 100 parts by weight magnetite, BL
-5P 150 tons 171 parts (manufactured by Titan Kogyo Co., Ltd.) Low-molecular polypropylene, Viscol 680P (Sanyo Kasei T-gyo Co., Ltd. V) 7.5 small parts The mixture was kneaded by rollers, cooled, crushed, and classified to obtain a magnetic toner having an average particle size of 15 pm. The obtained toner was divided into five equal parts, and 0.4 parts by weight of silica having different average particle diameters per 100 parts by weight of the binder resin contained in the toner was added and mixed to form a one-component developer. -5 were prepared (see Table 1).

Electronic copying machine U-B+x V2 (Konishi Roku Photo Industry Co., Ltd.)
The photosensitive drum (manufactured by Kawasaki Co., Ltd.) was changed to a selenium photosensitive drum with a roughened surface, and the developer was loaded into a test copying machine whose developing device was modified to use a one-component developer.
Continuous copying test up to oo sheets was performed, and the initial copying start time was 10
The toner transferability, the separation state of the transfer paper, the cleaning state, and the surface state of the photoreceptor were compared by visual judgment after 0 copies and after 10,000 copies were made.

As shown in Table 1, when samples No. 1, tb, and 2 according to the present invention were used, even after copying 10,000 sheets, good toner transfer, transfer paper separation, and cleaning conditions were almost the same as at the start of the test. For comparison, samples 1'b and 3.4.5., which used finer silica particles, had toner transferability,
The cleaning condition gradually deteriorated, and after 10,000 copies, only copies with low contrast and many background stains were obtained. The transfer paper often became wrapped around the photoreceptor, causing jamming. The surface of the photoreceptor is also sample No.
, 1 and 2, the matte state due to fine irregularities was maintained from beginning to end, whereas the amount of sample.

In the case of 3.4.5, the gloss increased and the uneven portions were observed to be worn.

Example 2 Styrene-acrylic resin, Hymer SDM73100 parts by weight carbon black, manufactured by Mocal Shikaku Capot) 10
Part by weight Low molecular weight polypropylene, Viscoel 660P 3 parts by weight The above raw material 1 was sufficiently premixed in a ball mill as in Example 1, then kneaded by a hot roller, cooled, pulverized and classified, and the obtained toner was mixed with 2 parts by weight. divided and averaged on one side -
A toner according to the present invention, sample amount 6, was prepared by adding 0.4 parts of silica fine powder having a secondary particle size of 40 m p- per 100 parts by weight of the binder resin in the toner. In addition, the same amount of silica fine powder with an average primary particle size of 8 mg as in the above sample was added to the other half to prepare a comparative sample amount 7.

” 2 parts of the 2 types of samples are 98 parts each! - Prepare two types of two-component developer by mixing with 1 part of resin-coated iron powder carrier, and continuously load it into a test copying machine equipped with a rough selenium drum of the same type as that used in Example 1. A copying test was conducted.

When using the toner of the present invention, sample size 6, the number of copies is 10
Even if it reaches ,000, there are no good copies! However, when toner No. 7, which is a comparison sample, was used, the image density gradually decreased, and due to poor cleaning, background smudges occurred, and the actual number of copies was 3,000. The test was discontinued when it reached an unacceptable level.

〔Effect of the invention〕

As seen in the above examples, by using the developing method of the present invention containing silica particles with an average primary particle diameter of 40 to 100 mg, the repeated use durability of the roughened selenium photoreceptor can be greatly improved. can do.

Agent: Patent Attorney No. 111 Stepparent

Claims (3)

[Claims] (1) An electrostatic image formed on a photoconductive photoreceptor with an appropriately roughened surface is
A method for developing an electrostatic image, the method comprising developing an electrostatic image using a developer containing m g of silica. (2) The method for developing an electrostatic image according to claim 1, wherein the photoconductive photoreceptor is a selenium-based photoreceptor. (3) The method for developing an electrostatic image according to claim 1, wherein the unevenness of the surface of the photoreceptor is 0.1 to 0.2 μm.