JPS60263161A - Formation of image - Google Patents

Abstract

PURPOSE:To prevent disturbance of a latent image even under circumstances of high temp. and high humidity by developing the latent image of the an org. photoconductive sensitive body by using a specified developer. CONSTITUTION:The developer is prepared by adding the combination of a fine metal oxide powder having a BET specific surface area of 0.5-500m<2>/g measured by the nitrogen adsorption method, and a fine metallic nonoxide powder in an amt. of 0.01-10pts.wt. and 0.1-10pts.wt. per 100pts.wt. of a magnetic toner, respectively. As the fine metal oxide powder, fine silica powder contg. >=85wt% SiO2 is especially desirable. As the fine metal nonoxide powder, fine SiC powder is especially desirable. As the org. photoconductive sensitive body, an org. photoconductive polymer, such as polyvinylcarbazole, and an org. photoconductor low in mol.wt. dispersed into an insulating polymer binder, etc., are enumerated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, particularly an organic photoconductive photoreceptor (OPC).
).

As a photoconductive material used in an electrophotographic photoreceptor, a St
Inorganic photoconductive materials such as % selenium, cadmium sulfide, and zinc oxide are known. These photoconductive materials have a number of advantages, including the ability to be charged to a suitable potential in the dark;
Although it has advantages such as less charge dissipation in the dark and the ability to quickly dissipate charge by irradiation with light, it also has various disadvantages. For example, in selenium-based photoreceptors, crystallization easily progresses due to factors such as temperature, humidity, dust, and pressure. Especially when the ambient temperature exceeds 40°C, crystallization becomes significant, resulting in decreased charging performance and white images. It has the disadvantage of causing spots. In addition, selenium-based photoreceptors and cadmium sulfide-based photoreceptors have the disadvantage that stable sensitivity and durability cannot be obtained when used over time under high humidity.

In addition, zinc oxide photoreceptors require the sensitizing effect of sensitizing dyes such as rose bengal, but such sensitizing dyes cause charge deterioration due to corona charging and photobleaching due to exposure light, so it may take a long time. It has the disadvantage that it cannot provide a stable image over a long period of time.

Furthermore, various organic photoconductive polymers including 1-polyvinylcarbazole have been proposed, but these polymers have poor film formability, light weight, high productivity, etc. compared to the inorganic photoconductive materials mentioned above. Despite their superiority, it has been difficult to put them into practical use until now because they are inferior to inorganic photoconductive materials in terms of sensitivity, durability, and stability against environmental changes. Moreover, an appropriate sensitizer that can provide sufficiently high sensitivity has not yet been found.

For this reason, in recent years, many low molecular weight organic photoconductive substances have been developed in place of polymer-based organic photoconductive substances.

The advantage of low-molecular-weight organic photoconductive materials is that the range of compounds that can be selected has expanded, and by selecting those with good sensitivity and charge retention, it is possible to This means that the defects of the photoreceptor can now be improved.

As mentioned above, photoreceptors made of organic photoconductors, both low-molecular and high-molecular ones, have excellent properties, but on the other hand, they have the disadvantage of having a low surface hardness and being easily scratched. For this reason, it is not possible to strongly clean the surface of the photoreceptor, and in order to remove low-resistance substances generated on the surface of the photoreceptor due to corona discharge, paper powder, and other low-resistance substances attached to the surface, Particularly in a high-temperature, high-humidity environment, the substance absorbs moisture, resulting in an extremely low resistance and a tendency to disturb the latent image.

On the other hand, after studying various methods to overcome these drawbacks of OPC photoreceptors, we found that it is effective to use toner containing fine particles of appropriate hardness for OPC photoreceptors such as magnetic powder. I found it.

The applicant of the present invention first triboelectrically charges the electrostatic image in Japanese Patent Application Laid-Open No. 54-43036, and then develops it by placing it in close proximity to, but not in contact with, an electrostatic image and facing it under the action of a magnetic field.

According to this method, by applying a very thin layer of magnetic toner to the sleeve cloth, the chances of contact between the sleeve and the toner are increased, and sufficient frictional electrification is possible. By moving the toner relatively, the toner particles are disaggregated and sufficiently rubbed against the sleeve, and the toner is supported by magnetic force and developed by facing the electrostatic image without coming into contact with it.K Excellent images can be obtained by preventing soil blurring. However, although this method uses a magnetic toner, when applied to an OPC photoreceptor, the above-mentioned disturbance of the latent image could not be eliminated.

Therefore, an object of the present invention is to provide an image forming method that overcomes the above-mentioned defects and does not cause disturbance of latent images even in a high temperature and high humidity environment.

That is, the present invention provides a process for forming a developer layer containing a metal oxide fine powder, a metal non-oxide fine powder, and a magnetic toner on a developer holding member, and a process for forming a latent image on a photoreceptor using the developer layer. The image forming method includes a step of visualizing the toner, wherein the developer is made of a magnetic toner that does not substantially contain a magnetic carrier. In contrast to the above method,
The method of the present invention can overcome the drawback that the latent image of the OPC photoreceptor is easily disturbed because the magnetic toner layer is
It is presumed that this was due to contact with the PC photoreceptor.

Examples of the organic photoconductor used in the present invention include those using an organic photoconductive polymer such as polyvinylcarbazole, and those using an insulating polymer as a binder for a low molecular weight organic photoconductive substance. Among these, a laminated photoreceptor consisting of a charge transport layer and a charge generation layer is preferably used in the present invention. , quinone pigments such as indanthrene brilliant violet RRP, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, bisbenzimidazole pigments such as India First Orange Toner, 7-thalocyanine pigments such as copper phthalocyanine, quinacridone pigments, etc. It is formed by dispersing a charge-generating substance in a binder resin such as polyester, polystyrene, polyvinyl pteral, polyvinyl pyrrolidone, methyl cellulose, polyacrylic acid esters, or cellulose ester. Its thickness is o, oi-iμ, preferably 0605 to 05μ.

In addition, polycyclic aromatic compounds such as anthracene, pyrene, phenanthrene, coronene, or indole, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, etc. are added to the main chain or side chain of the charge transport layer.
It is formed by dissolving a hole-transporting substance such as a compound having a nitrogen-containing cyclic compound such as oxadiazole, pyrazoline, thiadiazole, or triazole, or a hydrazone compound in a resin that has film-forming properties. This is because the charge transporting substance generally has a low molecular weight and has poor film-forming properties by itself. Examples of such resins include polycarbonate, polymethacrylic acid esters, polyarylate, polystyrene, polyester, polysulfone, styrene-'7 crylonitrile copolymer, styrene-methyl methacrylate copolymer, etc. The thickness of the charge transport layer is 5-2
0μ is preferred. Properties such as abrasion resistance and oil lubricity are also important for the resin that constitutes the surface layer of the photoreceptor, such as the charge transport layer. The temperature is preferably 60°C or higher, particularly 80°C or higher.

In addition, the surface hardness of the OPC photoreceptor using the FiAVC of the present invention is measured by the method shown below, and is 10 g or more, especially 1
It is preferable that it is 2-100g.

The above hardness is measured as follows.

For example, the OPC photoreceptor is fixed on a sample stage of a HEIDON 14 type surface property measuring machine (Shinto Kagaku!), and a diamond needle (conical, with a cone angle of 90',
However, the tip has a diameter of 0. OI Jll's hemispherical shape. ), apply a vertical load to the sample stand at 50
Move at a speed of 1111/min to scratch the surface of the OPC photoreceptor. The width of this scratch is measured using a microhardness meter MVK, for example.
-Measure using the attached microscope (manufactured by Akashi Seisakusho).

Perform the above operation with the load xg being 10g or 15g, for example.

20 g, 25 g, 30 g, 35 g, 40 g,
. . . Repeatedly, from the linear regression relationship between the scratch width and the load, calculate the load that will cause a 50μ scratch, and
This is the hardness of the PC photoreceptor. If the oPc photoconductor is a drum, the scratches should be made in the axial direction of the drum.
Set the OPC photoreceptor on the sample.

Furthermore, those containing a vinyl polymer at least 30% by weight, preferably at least 50% by weight, particularly preferably at least 70% by weight are preferred. The vinyl polymer is a monopolymer of vinyl monomers or a copolymer of two or more vinyl monomers, and vinyl monomers include styrene, P-chlorostyrene, vinyltoluene, methyl methacrylate, acrylonitrile, Examples include N-vinylcarbazole, and may also be a copolymer with a monomer such as a diene monomer that can be polymerized with a vinyl monomer.

As the binder resin of the toner used in the present invention, monopolymers of styrene and its substituted products such as polystyrene, polyP-chlorostyrene, and polyvinyltoluene;
-Chlorstyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-
Vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, Sunalene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, Styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene/-inbre/copolymer, styrene-7crylonitrile-indene copolymer, styrene-maleic acid copolymer Polymers, styrenic copolymers such as styrene-maleic ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral , polyamide, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated halaffin, paraffin wax, carnauba wax, etc. alone or in combination. It can be used as

Further, as the magnetic powder contained in the magnetic toner used in the present invention, a substance that is magnetized by being placed in a magnetic field is used, such as powder of a ferromagnetic metal such as iron, cobalt, or nickel, or magnetite/γ-Fe, There are alloys and compounds such as O, ferrite, etc.

In particular, in order to exhibit the above-mentioned effects, the BB'l specific surface area determined by the nitrogen adsorption method is preferably from 2 to 20 g/f, particularly from 2.5 to 12 g/f. The content of this magnetic powder is preferably 10 to 70% by weight based on the weight of the toner.

Furthermore, the magnetic toner used in the present invention has a BET specific surface area of 065 to 500 go/f1, especially 50 to 4
It is preferable to add metal oxide fine powder and metal non-oxide fine powder together at a rate of 00 rrt/f. This is because the addition of such fine powder reduces the disturbance of the latent image mentioned above.

This is thought to be because such fine powder has a large specific surface area, so that the low-resistance substance adhering to the drum is adsorbed or attached to its surface and removed.

That is, the addition of metal oxide fine powder alone is highly effective in imparting triboelectric charging properties and development durability, but cannot exhibit sufficient effects in terms of ``disturbance of one latent image''.

The reason for this is that the latent image is disturbed because ozone-degraded substances on the 020 surface become conductive at high humidity, and unless this thin film is removed, the latent image cannot be effectively prevented from being disturbed.

Therefore, the 020 surface must always be fresh.

By the way, the metal non-oxide fine powder of the present invention is effective in removing this thin film. That is, this metal non-oxide fine powder is trapped by the cleaner grade of the electrophotographic process and constantly keeps the 020 surface fresh. The thickness of the thin film to be removed is approximately 50 to 100 λ, which is related to the hardness K of the surface layer of the OPC when converted to a durability of 3000 sheets, and this change in thickness has no relation to the latent image. Examples of such metal oxide fine powders include alumina, titanium dioxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, cinnabar earth, Various inorganic metal oxide pigments, chromium oxide, cerium oxide, red iron oxide,
Antimony trioxide, zinc oxide-bismyth oxide, bismyth oxide, magnesium oxide, zirconium oxide, beryllum oxide, Pb(ZrxTH-x)0. .

Zn(l-x)MnxF'e, 0. (Both 0<x
Powders or particles such as <1) may be mentioned, but Silly fine powder is particularly preferred.

Here, the flat silica fine powder is a fine powder having a 5i-0-8i bond, and includes both those manufactured by a dry method and those manufactured by a wet method.

Various conventionally known methods can be used to produce fine silica powder using a wet method. For example, the decomposition of sodium silicate with an acid can be expressed as a general reaction formula (the reaction formula is omitted): Na, O xsio, +-HCe+H, O→SiO,
・nH, O+NaC/Other methods include decomposition of sodium silicate with ammonia salts or alkali salts, generation of alkaline earth metal silicate from sodium silicate, and then decomposition with acid to produce silicic acid, sodium silicate solution There are methods such as converting it into silicic acid using an ion exchange resin, and using natural silicic acid or silicate.

The silica fine powder mentioned here includes anhydrous silicon dioxide (silica), aluminum silicate, sodium silicate,
Any silicate such as potassium silicate, magnesium silicate, or zinc silicate can be applied. The particle size is preferably within the i curve of 0.01 to 2 μ as an average primary particle size. Further, it is desirable that the content of Sj is 85% by weight or more. Silica fine powder produced by a dry process, so-called dry process silica, or fumed silica, is produced by a conventionally known technique. For example, this method utilizes a thermal decomposition oxidation reaction of silicon tetrachloride gas in an acid-free hydrogen flame, and the basic reaction formula is as follows.

5jC14+-28+O7→S iO,+-4HClAlso, in this manufacturing process, for example, by using other metal halide compounds such as aluminum chloride or titanium chloride together with a silicon halide compound, a composite fine powder of silica and other metal oxides can be produced. It is also possible to obtain the sterilized body, and the present invention encompasses these as well.

The average primary particle size of the particles is desirably within the range of 0.001 to 2μ, particularly preferably 0.00μ.
It is preferable to use silica fine powder within the range of 2 to 0.2 microns.

Specifically, there are various types of commercially available silica as these fine silica powders, but those having hydrophobic groups on the surface are preferred (
7. For example, R-972 (manufactured by Aerosil), Taranox 500 (manufactured by Talco), and those treated with other silane coupling agents, titanium coupling agents, silicone oil, silicone oil having an amine in the side chain, etc. is good.

In addition, SjC and AIN are used as non-carbonated fine powders.

MoS 17 , LaB, , B4C+ Tr
C+ W C+ T iN rr Si, N,, Mob, , h-B N, I C
, AIC)N, etc. 08IC fine powder, which can be used to form gold carbides, metal tinides, metal sulfides, metal silicides, etc., is particularly preferred.

It is particularly preferable that the particle size is #'i 0.1 .mu. or less and the oil absorption amount is 5 to 50 m/100 I of the non-carbon fine powder.

Manufacturing methods for these fine powders include mechanical pulverization, atomization, sintering, evaporation in gas, plasma evaporation, and hydrogen 7'-
heating, oil surface evaporation, high frequency induction heating, arc evaporation, pyrolysis, CVD, gas ring origin.

Examples include silica decomposition and active hydrogen melting methods.

For example, as an example of the CVD method, there are three ways to make TIN as follows.

Ti(,'/C7 (1) 21'iC1,(gas) + N2(gas
) −+ 2'l'1N(solid)+4 C6y
(gas) (2) 2TiClt(gas) +N, (gas)
+ 4H, (gas) - + 2'l'1N (sol i
d) +814CA! (gas) (3) TiC1
, (gas) + NH, (gas) −+ ']”1
N(solid id) 10nHCA'+C/ Also, there are two ways to make Si3N4fl) NH3
(gas) + Ht(gas) + S i C”, l
, (gas) → S+3N4 (21S i (Nl(2), +S i (NH), →
Si, N, H, → Si, N, H → Si, N4 In addition, as a method for making SIC, S1 crystals and gelaphite (,'~D method and sintering method are 1200-1500℃ [11BCIs -m-=BN 1100-1700°C (2-TJC14--1--TJN 2000-2500°C [3) ZrCl+ □ ZrN 1100-1300jif4) VCl4---- + VN, etc.

Further, when the metal oxide wt powder and the metal non-oxide powder of the present invention are used in an amount of 0.01-10 parts by weight and 0.1-10 parts by weight per 100 parts by weight of the magnetic toner, It is especially preferable to add 0.1 to 2 parts by weight or 0.1 to 5 parts by weight of each.

If necessary, conventionally known carbon blanks, self-phthalocyanine, iron black, etc. can be used as color materials for the toner used in the present invention, and conventionally known charge control methods can be used in the present invention. used for. For example, potassium dimethyl-hexadecyl rno7nium chloride, decyl-trimenalan7nium chloride, nigrosine, safrani/
r and crystal violet metal complex salts.

Furthermore, the toner of the present invention may contain lubricants, isoelectricity imparting agents, fixing aids, etc., such as polytetrafluoroethylene powder, polyfluorinated and nylide powder, metal salts of higher fatty acids, carbon blanks, etc., as necessary. Low molecular weight polyethylene, low molecular weight polypropylene, etc. may be added.

The volume resistivity of the magnetic toner of Zarani Honshuto 11 is 101
It is preferable that the resistance is 0Ωc11 or more, especially 10'2Ωcm. The volume resistivity obtained here is obtained by molding the toner with an output of 9/crA to 100, applying an electric field of 100 V/c- to it, and converting it from the current value after applying 01 minutes'ttvi. defined.

An example of the developing device used in the present invention is shown in FIG. 1. In the figure, by rotating at least one of the sleeve '3 or the multipolar magnetic agent 4, the magnetic toner 2 is conveyed in the direction of the arrow, and the magnetic tree 2 is transported. is regulated by the flade 5vc to form a magnetic toner layer 6. It is set so that the magnetic toner on the generated sleeve 3 comes into contact with the photoreceptor 1rC at the sixth development section. A bias voltage may be applied between the sleeve 3 and the photoreceptor 1.

As the transfer method used in the present invention, conventionally known methods such as electrostatic transfer method, bias roll method, FE, M transfer method, and magnetic transfer method are used. Furthermore, methods for cleaning residual toner on the photoconductor include the conventionally well-known blade cleaning nog method and fur brush cleaning method.
2/G method, magnetic brush cleaner 2/G method, etc.
Ill. Before the cleaning/cleaning process, an expulsion process or the like may be provided as necessary to clean the toner.

In addition to the VL cleaning method of the present invention, the blade cleaning nog method is preferable in combination with the toner of the present invention and the S light material.

[Example 1] Styrene-butyl methacrylate-dimethylamitsuyutyl methacrylate (weight ratio 7:25:0.5) copolymer 100-layer lid, EET specific surface area 5 n1'/i magnetite 80 m lid, 3 parts by weight of polyethylene wax were mixed and melted and kneaded using a roll mill. After cooling, the mixture was coarsely ground in a Hanoma mill and then finely ground in a Zient grinder 4iII.

Next, the particles are classified using an air classifier and the particle size is approximately 5 to 20 cm.
Obtain a black powder of μ.

On the other hand, fine silica powder synthesized by dry method (specific surface area approximately 130rrr'/7) 100! 1 part of silicone oil with amine in the side chain (2 parts
Viscosity at 50°C 70 cps, per amine [1830]
12 ml of IF part, 1ap! Keep the temperature at 250℃ and process for 60 minutes. The amount of triboelectric charge of the produced treated silica is +130μc/1! was.

To 100 parts by weight of the black fine powder, 0.4 parts by weight of the silica fine powder treated with the silicone oil having an amine in the side chain and 1.0 parts by weight of 5iC were added to prepare a developer.

In addition, StC powder contains silica and cortus with a ratio of 1800 to 1
Particle size of pulverized after reacting at 900°C is 0. IAm's was used.

Also oil absorption 1t-4100,? 251J of linseed oil was adsorbed per unit.

The volume resistivity of this developer was 14 Ωcow. On the other hand, if@transport layer]) S Cr added 'I' g Methyl methacrylate-Styrene at 80°C or higher/(Gravity ratio 9:l) Laminated type OPCF made of copolymer
f! A photoreceptor was created on a conductive cylinder to obtain the entire photosensitive drum. The hardness of the photoreceptor surface was found to be 21.9 by the measurement method described above.

This photosensitive drum has a linear surface speed of -6 k at a linear surface speed of 66 kam/sec.
It is uniformly charged with a corona group of V, and then the original image is irradiated to form a latent image. This latent image is shown in Figure 1 with a sleeve diameter of 50 mm and a sleeve surface magnetic flux density of 700 mm.
Gauss, number of magnetic poles 12, blade-sleeve k 0.4
The distance between the photosensitive drum surface and the sleeve surface is set to 0.3 mm in the sleeve rotation developing device, and a bias voltage of 100V is applied to the sleeve surface m+IC-100V, and the formation on the sleeve is performed using the Fhr toner. One layer of toner was brought into contact with a photosensitive drum for development, and then a powder image was transferred from the back side of the transfer paper while irradiating -7kY corona, and fixed with a heating roll. A clear image was obtained. A running test of 3,000 sheets was conducted under high temperature and high humidity conditions (32° C., 90%), and good images with no image disturbance were obtained.

[Example 2] The same procedure as in Example 1 was performed except that a styrene-acrylonitrile copolymer having a Tg of 80°C or higher was used instead of the methyl methacrylate-styrene copolymer of Example 1. The results were obtained. The hardness of the photoreceptor surface was 15.9.

[Example 3] In place of the fine silica powder of Example 1, fine silica powder (specific surface area approximately 2 oom'/&) synthesized by a dry method was mixed with 15% aminopropyltriethoxysilane and amino-modified silica/oil ( Viscosity 750 cps, amine equivalent 1
900) S10 of Example 1 using silicic acid fine powder B() ribonite load + 160 μC/fl) produced by treatment with 15%
Example 1 except that 8i1N4 is used instead of
It was done almost the same way.

The 5iN9 powder used was made by reacting ammonia gas, hydrogen gas, and silicon tetrachloride gas (7+), the particle size was 0.08 μm, and the oil absorption amount was 100 g/t (
Adsorbed 28 grams of linseed oil. It was good. The internal phase resistivity of the toner was 100 cm.

[Example 4] Good results were obtained in the same manner as in Example 1 except that methyl methacrylate with a Tg of 80°C or higher was used instead of the methyl methacrylate-styrene/copolymer of Example 1. was gotten. The hardness of the photoreceptor surface was 26.9.

[Example 5] ICB E 'I' Lt surface phase is 6m'/9 r-F"e instead of magnetite, 03 is used for 90 claw part Z
When the same procedure as in Example 1 was carried out except for the above, a good image with less image disturbance was obtained. The volume resistivity of the toner was 1O111ΩCl11.

[Real 1-f! A6,7) B E T J-J surface area is 3n1'/, 9 and 10
m171! Example 1 was carried out in the same manner as in Example 1, except that magnetite whose surface was treated with a titano coupling agent was used. Good results were obtained.

[Example 8] Using a toner to which 0.6% of subconductive graded steel with a +3 E i' specific surface area of 55rn'/& was further added was used.The same procedure as in Example 1 was carried out except for the use of a toner that further added 0.6% of subconductive graded steel with a specific surface area of 55rn'/&. The results were obtained.

Furthermore, good results were obtained using a photoreceptor made of a high-molecular organic photoconductor containing phorihinyl-rubazole.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an example of a developing device used in the present invention. 1...OPC photoreceptor 2...Magnetic toner 3...Sleeve 4...Multi-polar magnet 5...Blade 6...Magnetic toner single layer

Claims (1)

[Claims] (1) Step of forming a developer layer containing metal oxide fine powder, metal non-oxide fine powder, and magnetic toner on a developing agent holding member, and developing a latent image on a photoreceptor using the developer layer. An image forming method comprising a step of converting the image.