JPH03197962A - Developer - Google Patents

Abstract

PURPOSE:To stably form an image free from black spots without causing defective cleaning by using a developer for an amorphous silicon (a-Si) photosensitive body contg. colored particles and combined fine particles obtd. by sticking specified inorg. fine particles to the surfaces of specified resin particles. CONSTITUTION:An electrostatic charge image formed by an image forming process on an a-Si photosensitive body is developed with a developer contg. colored particles contg. a colorant and resin and combined fine particles obtd. by sticking inorg. fine particles having 0.01-1mum average particle size to the surfaces of resin particles having 10-500kg/cm<2> yield value at 20 deg.C and 0.1-7mum average particle size as nuclei. When the combined fine particles are put between a cleaning member and the photosensitive body and receive high pressing force, the resin particles are moderately deformed to relieve the intense rubbing action of the inorg. fine particles and the resin particles are hardly broken. A image free from black spots can stably be formed without causing defective cleaning.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to image formation in which an image is formed through the steps of forming an electrostatic image, developing, transferring, and cleaning using an amorphous silicon photoreceptor. Regarding the developer used in the process.

[Conventional technology]

In an example of electrophotography, an electrostatic image is formed on a photoconductor by charging and exposure, this electrostatic image is developed with a developer containing toner to form a toner image, and this toner image is then transferred. The image is transferred to a material and fused to form a visible image.

On the other hand, toner remaining on the photoreceptor without being transferred to the transfer material is cleaned by a cleaning member placed in pressure contact with the surface of the photoreceptor.

As a toner constituting a developer used in such an image forming process, a toner containing colored particles and composite fine particles made of resin particles whose surface is treated with inorganic fine particles has been proposed. (Unexamined Japanese Patent Publication No. 1983-
91143).

In the above publication, as the resin constituting the resin particles,
Acrylic polymers, acrylic/styrene polymers, polymers or copolymers of nitrogen-containing addition polymerizable monomers, polymers or copolymers of addition polymerizable carboxylic acids, fluororesins, and silicone resins are used. is listed.

[Problem to be solved by the invention]

However, in the toner disclosed in the above publication, the resin constituting the resin particles that serve as the core of the composite fine particles is hard and brittle. It turned out there was a problem.

(1) In order to improve cleaning performance in the cleaning process, when cleaning is performed by placing a cleaning member in contact with the surface of the amorphous silicon photoreceptor with a relatively large pressure contact force, the gap between the cleaning member and the surface of the amorphous silicon photoreceptor is Since the composite fine particles sandwiched between the composite particles are subjected to a large pressure contact force, the surface of the amorphous silicon photoreceptor is strongly rubbed by the inorganic fine particles existing on the surface of the composite fine particles, causing damage, and the resin particles forming the core of the composite fine particles is destroyed, resulting in poor morphology and surface properties of the composite fine particles, resulting in a problem of poor cleaning.

(2) When the resin particles are broken in this way, fine resin powder is generated, and this fine resin powder is pressed against the surface of the amorphous silicon photoreceptor by the cleaning member, so that the surface of the amorphous silicon photoreceptor is filmed.
There is a problem that the surface characteristics of the photoreceptor deteriorate early and the image density decreases as images are repeatedly formed.

(3) In addition, when resin particles are destroyed, inorganic fine particles are liberated and inorganic fine powder is generated, and this inorganic fine powder also damages the surface of the amorphous silicon photoreceptor, and this inorganic fine powder is used as the amorphous silicon photoreceptor. As a result, when the next image is formed, the toner adheres to the embedded inorganic particles and is fixed, causing black spot-like stains (black spots) on the image. There is a problem that occurs.

An object of the present invention is to provide a developer that can prevent the destruction of composite fine particles and stably form images with high image density and no black spots many times without causing cleaning failures. be.

[Means to solve the problem]

In order to achieve the above object, in the present invention, an electrostatic charge image is formed on an amorphous silicon (referred to as RA-3i J) photoreceptor, and this electrostatic charge image is developed with a developer to form a toner image. In a developer used in an image forming process that includes a step of forming a toner image, transferring the toner image to a transfer material, and cleaning the toner remaining on the a-3i photosensitive material, the toner constituting the developer is Colored particles containing at least a resin and a colorant have a yield value of 10 to 500 kg/cm2 at 20°C and an average particle size of 0.1 to 7. On the surface of the resin particles of um, the average particle size is 0.
．． A structure including composite fine particles formed by fixing inorganic fine particles of 0.01 to 1 μm is adopted.

That is, in the present invention, by using resin particles whose yield value at 20° C. is within a specific range as the core of the composite fine particles, due to the tenacious physical properties of the resin particles, It prevents destruction of resin particles, thereby improving cleaning performance, and also prevents filming on the surface of the a-3i photoreceptor, and prevents the occurrence of black spots caused by damage to the surface of the photoreceptor. This is what I did to get it.

To explain in detail, the resin particles that form the core of the composite fine particles are
Since the yield value at 20°C is within a specific range, the resin particles can be deformed without being destroyed by appropriately following the compression pressure when subjected to compression pressure at room temperature. It has strong physical properties.

Therefore, when cleaning residual toner with a cleaning member placed in contact with a hard a-Si photoconductor with a relatively large pressure contact force, the composite fine particles are sandwiched between the cleaning member and the photoconductor and a large pressure contact force is applied. When received, the resin particles deform appropriately and exert a cushioning effect.
Therefore, the strong abrasion effect caused by the inorganic fine particles is considerably alleviated, and there is little risk that the resin particles will be destroyed. Therefore, fine inorganic particles and resin particles are not generated, and the image density is sufficient without causing cleaning defects.
Images without black spots can be stably formed many times.

Hereinafter, the configuration of the present invention will be specifically explained.

The fine composite particles constituting the developer of the present invention have a yield value of 10 to 500 kg/cm at 20°C, preferably 20
~300kg/cm” with an average particle size of 0.1-7μm
Preferably, resin particles of 0.2 to 5 μm are used as cores, and inorganic fine particles having an average particle diameter of 0.01 to 1 μm, preferably 0.01 to 0.5 μm are fixed to the surface of the resin particles.

Here, the yield value is JIS K 7113-1981
This refers to the value measured by the method specified in .

A resin having a yield value of 10 to 500 kg/cm2 at 20 DEG C. is moderately deformed by compression pressure at room temperature, but has tenacious physical properties that will not completely break or fracture.

On the other hand, when the yield value of the resin constituting the resin particles at 20°C is less than 10 kg/cm2, the resin particles are greatly deformed even by a slight compression pressure, so the composite fine particles do not exhibit a good rolling effect. , the fluidity of the toner decreases, and the adhesion force to the a-3i photoreceptor increases, resulting in poor cleaning.

On the other hand, when the yield value at 20°C of the resin constituting the resin particles exceeds 500 kg/cm, the resin does not have enough tenacity, so the resin particles are difficult to deform when subjected to a large pressing force from the cleaning member. The abrasive action of inorganic fine particles appears greatly, and therefore a-3i
The surface of the photoreceptor is easily damaged, and the resin particles are rapidly destroyed, resulting in poor cleaning.Furthermore, fine powder of resin particles and inorganic particles is generated, resulting in a
Image density decreases due to filming on the surface of the -3i photoreceptor, and black spots are likely to occur due to damage to the surface of the a-3i photoreceptor.

The average particle diameter of the resin particles constituting the composite fine particles is 0.1 to
The thickness is 7 μm, preferably 0.2 to 5 μm. Here, the average particle size of the resin particles is measured using a laser diffraction particle size distribution measuring device r IIELO3COMP manufactured by SYMPATEC.
ETITION/3 Refers to the volume-based average particle size measured by J.

If the average particle size of the resin particles is within this range, the composite fine particles will exhibit a good rolling effect, that is, the composite fine particles of a suitable size will be interposed between the colored particles, and a good lubricating effect will be exerted. Therefore, the cleaning performance of the toner is improved, and there is no fear that the triboelectric charging property of the toner is inhibited, so that an image with high image density can be formed.

On the other hand, when the average particle size of the resin particles is less than 0.1 μm, the cleaning performance tends to deteriorate because the rolling action of the composite fine particles becomes insufficient.

Conversely, when the average particle size of the resin particles exceeds 7 μm,
Since the triboelectric charging properties of the toner are inhibited, image density tends to decrease.

The resin constituting the resin particles of the composite fine particles has a temperature of 20°C.
The resin is selected from resins having a yield value in the range of 10 to 500 kg/cm2, preferably 20 to 300 kg/cm, and specifically, ethylene-vinyl acetate copolymer, polyurethane, vinylidene chloride resin, chloride resin, etc. Vinyl resin, ABSIII!, etc. can be used.

The average particle size of the inorganic fine particles constituting the composite fine particles is 0.0
1 to IA1m, preferably 0.01 to 0.5 μm.

Here, the average particle size of inorganic fine particles refers to the average particle size of primary particles, and refers to the number-based average particle size observed with a scanning electron microscope and measured by image analysis.

If the average particle size of the inorganic fine particles is within this range, good cleaning properties will be exhibited, and furthermore, a suitable polishing action will be exhibited, and deteriorated parts or filming parts on the surface of the photoreceptor will be effectively removed and the photoreceptor will be Body surface properties are maintained stably over a long period of time.

On the other hand, when the average particle size of the inorganic fine particles is less than 0.01 μm, they tend to be buried in the resin particles (and the cleaning performance becomes insufficient. Conversely, when the average particle size of the inorganic fine particles is less than 1
When it exceeds μm, it is difficult to adhere to the surface of the resin particles, and the surface of the photoreceptor is easily damaged by the free inorganic fine particles.

Inorganic materials that make up the inorganic fine particles include silicon oxide, aluminum oxide, titanium oxide, pyrozinc oxide, zirconia oxide, chromium oxide, cerium oxide, tungsten oxide, antimony oxide, copper oxide, tin oxide, ternope oxide, manganese oxide, Oxides such as boron oxide, barium titanate, aluminum titanate, magnesium titanate, calcium titanate, strontium titanate, ■ carbides such as silicon carbide, tungsten carbide, boron carbide, titanium carbide, ■ silicon nitride, titanium nitride, Nitride such as boron nitride, etc. can be used.

The composite fine particles are composed of the above inorganic fine particles fixed to the surface of the above resin particles. Here, adhesion refers to a state in which the inorganic fine particles are not simply attached to the resin particles by electrostatic force, but the length of the part of the inorganic fine particles embedded in the resin particles is 5 to 95%. Such a state can be confirmed by observing the surface of the composite fine particles using a transmission electron microscope or an ordinary electron microscope.

When fixing inorganic fine particles to the surface of resin particles,
It is preferable that the resin particles are first sphericalized and then the inorganic fine particles are fixed to the surface of the resin particles. This is because when the resin particles are spherical, the inorganic fine particles are evenly fixed, and separation of the inorganic fine particles is effectively prevented. On the other hand, if irregularly shaped resin particles are used, the inorganic fine particles will not adhere to the surface of the resin particles uniformly.
Inorganic fine particles become easily liberated. Moreover, the surface of the resin particles is largely exposed.

Methods for making resin particles spherical include: (1) melting the resin particles by heat and then performing spray granulation; (2)
Examples include a method in which heat-molten resin particles are jetted into water to make them spherical, and (2) a method in which spherical resin particles are synthesized by a suspension polymerization method or an emulsion polymerization method.

As a means of fixing inorganic fine particles to the surface of resin particles,
A method in which inorganic fine particles and resin particles are mixed and then heat is applied, a so-called mechanochemical method in which inorganic fine particles are mechanically fixed to the surface of resin particles, etc. can be used. Specifically, ■Resin particles and inorganic fine particles are mixed, stirred and mixed using a Henschel mixer V type mixer, turbular mixer, etc., the inorganic fine particles are attached to the surface of the resin particles by electrostatic force, and then the inorganic fine particles are attached to the surface of the resin particles. A method in which resin particles with fine particles attached are introduced into a heat treatment device such as a Niro atomizer or a spray dryer, and heat is applied to soften the surface of the resin particles and inorganic fine particles are fixed to the surface. ■Electrostatic force is applied to the surface of the resin particles. After the inorganic fine particles are attached by a device that can apply mechanical energy by modifying an impact crusher, such as an Ong mill, a free mill,
A method of fixing inorganic fine particles to the surface of resin particles using a device such as a hybridizer can be adopted.

In obtaining composite fine particles, when blending inorganic fine particles with resin particles, the amount may be sufficient as long as the surface of the resin particles can be uniformly covered. Specifically, it varies depending on the specific gravity of the inorganic fine particles, but usually 5 to 60% by weight relative to the resin particles.
The inorganic fine particles are preferably used in a proportion of 5 to 40% by weight. With such a ratio, the inorganic fine particles can be fixed sufficiently uniformly to the surface of the resin particles. On the other hand, if the proportion of inorganic fine particles is too small, the cream's conductivity tends to decrease, and conversely, if the proportion of inorganic fine particles is too large, the inorganic fine particles tend to be liberated, resulting in a decrease in durability.

The above composite fine particles are added and mixed with colored particles to form a toner, and the blending ratio of the composite fine particles to the colored particles is 0. A range of 2.0% by weight is preferred. Within this range, fairly good leaning properties can be obtained, the triboelectric charging properties of the toner will not be inhibited, and good fluidity will be exhibited. On the other hand, when the blending ratio of composite fine particles is too small, cleaning performance tends to deteriorate. On the other hand, when the blending ratio of the composite fine particles is too large, the triboelectric charging properties of the toner are inhibited and the fluidity is lowered, so that the image density is likely to be lowered.

The colored particles constituting the developer of the present invention are colored particles containing at least a resin and a colorant.

The average particle size of the colored particles is usually in the range of 1 to 30 μm.

As the resin constituting the colored particles, polyester resin,
Styrene resins, acrylic resins, styrene-acrylic copolymer resins, epoxy resins, etc. can be used.

Colorants that make up the colored particles include carbon black, nigrosine dye, aniline blue, calco oil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green offsalate, and lamp black. , Rose Bengal, etc. can be used.

The colored particles may contain other additives as necessary. Examples of such other additives include charge control agents, fixability improvers, and the like.

As the charge control agent, salicylic acid derivatives and the like can be used.

As the fixing property improving agent, low molecular weight polyolefin or the like can be used.

Further, when obtaining a magnetic toner, magnetic particles are contained as an additive in the colored particles. As such magnetic particles, particles of ferrite, magnetite, etc. having an average particle size of 0.1 to 2 μm can be used. The amount of magnetic particles added is usually 20 to 70% by weight of the colored particles excluding external additives such as composite fine particles.

Further, in the present invention, inorganic fine particles may be added and mixed from the outside to the mixture of colored particles and composite fine particles to form a toner. These inorganic fine particles can further improve the fluidity of the toner. As such inorganic fine particles, in particular, silica fine particles whose surface has been treated with a hydrophobizing agent such as a silane coupling agent or a titanium coupling agent can be preferably used.

To give an example of a method for manufacturing the toner constituting the developer of the present invention, the resin constituting the colored particles, the colorant, and other additives used as necessary are mixed, melt-kneaded, and after cooling. It is crushed and classified to obtain colored particles with a desired average particle size. Next, the colored particles and composite fine particles are mixed using a device such as a Henschel mixer, and the composite fine particles are attached to the surface of the colored particles by electrostatic force to produce a toner.

The developer of the present invention may be a two-component developer composed of the above toner mixed with a carrier, or when the toner is a magnetic toner, a one-component developer composed only of the magnetic toner. It may be a type developer.

As the carrier constituting the two-component developer, a coated carrier in which the surfaces of magnetic particles are coated with a resin can be preferably used from the viewpoint of increasing the durability of the developer.

As such magnetic particles, particles of ferrite, magnetite, etc. can be used.

Further, as the coating resin, a resin such as a styrene-acrylic copolymer can be used.

The average particle size of the carrier is usually in the range of 30 to 150 μm.

The developer of the present invention forms an electrostatic charge image on the a-3i bad exposure light, develops this electrostatic charge image with the developer to form a toner image, and after transferring this toner image to a transfer material. , a-3
Used in an image forming process that includes the step of cleaning toner remaining on the photosensitive surface.

Each step will be specifically explained below.

(Electrostatic charge image forming step) The surface of the a-3i photosensitive material is uniformly charged using a corona charger or the like, and then image exposure is performed using an exposure optical system to form the a-3i image.
-3i Forming an electrostatic charge image on the irritating light.

As the a-5i photoreceptor, a laminated type a-5i photoreceptor having a surface modification layer can be particularly preferably used. This surface modified layer includes hydrogen atoms and/or
Or a layer in which dangling bonds are blocked by introducing halogen atoms (X) such as fluorine atoms (hereinafter referred to as ra-Si:
It is preferable that a modifying atom (Y) such as a carbon atom, an oxygen atom, or a nitrogen atom is further introduced into the "H(X) layer").

The laminated a-Si photoreceptor having such a surface modified layer is
It is non-polluting and has excellent light resistance, corona ion resistance, temperature and humidity resistance, and abrasion resistance.

The reason for the excellent wear resistance is thought to be that the bonding force between the introduced modification atoms (Y) and silicon atoms (sl) is greater than the bonding force between silicon atoms (sl). .

In addition, since the surface modification layer is hard, the physical adhesion of the toner to the a-Si photoreceptor is reduced, and in the transfer process, the toner is easily transferred from the a-Si photoreceptor to the transfer material. Transfer rate increases.

As a result of the higher transfer rate, the amount of toner remaining on the a-Si photoreceptor without being transferred is reduced, and embedding of toner in the surface modification layer is also prevented, resulting in improved cleaning performance.

In addition, the upper 8 self-surface modified layer itself has excellent photoconductivity, and due to the introduction of modifying atoms (Y), the dark resistance is 1012 to 10" Ω・cm (normal a- 3
In the i:H layer, it increases to 108 to 109 Ω・cm),
As a result, the charge retention ability of the a-Si photoreceptor is significantly improved. Furthermore, the repeatability of charging and exposure is also stable.

The surface modification layer may be laminated directly on the photoconductive layer, or may be laminated on the photoconductive layer provided with an intermediate layer.

The photoconductive layer may have a functionally separated layer structure in which charge generation and transport are shared by separate layers. When using such a multilayer photoconductive layer, the surface modification layer may be laminated on the outermost layer of the photoconductive layer.

FIG. 1 shows an example of a specific configuration of an a-Si photoreceptor.

10 is an a-Si photoreceptor. When the charging polarity is positive, for example, a drum-shaped base 1 made of aluminum or the like is used.
1, a P-type charge blocking layer 12, a charge transport layer 13, an intermediate layer 14, a charge generation layer 15, and a surface modification layer 16 are sequentially laminated on the a-Si photoreceptor 10.

The P" type charge blocking layer 12 is heavily doped with Group 3A elements (boron, aluminum, gallium, etc.), and is doped with modifying atoms (Y
) containing at least one of the following: a-3i: C:
H(X) layer, a-Si:C:O:H(X) layer, a-S
i:N:H(X) layer, a-3i:N:O:H(
X) layer, a-3i:○:H(X) layer, a-3i:C:O
:N:H(X) layer or the like is preferable. The content of the modifying atoms (Y) is preferably 0.5 to 4Q atm%. Further, the thickness of the charge blocking layer 12 is 0,
01 to 10 μm is preferable.

The charge transport layer 13 is lightly doped with a Group 3A element,
Moreover, like the charge blocking layer 12, it is preferable to configure the a-3i:Y:H(X) layer containing at least one kind of modifying atoms (Y) such as carbon atoms, oxygen atoms, and nitrogen atoms. The content of the modifying atoms (Y) is preferably 0.5 to 4Q atm%. Further, in order to improve charging ability and sensitivity, boron atoms may be introduced to make the material intrinsic. The thickness of the charge transport layer 13 is preferably 5 to 50 μm, and preferably thicker than the charge generation layer 15.

The intermediate layer 14 is provided as necessary to improve carrier injection efficiency, and is made of a-3i containing at least one kind of modifying atoms (Y) such as carbon atoms, oxygen atoms, nitrogen atoms, etc. :Y:H(X) layer is preferable. Further, the content ratio of the modifying atoms (Y, ) is preferably smaller than that of the charge transport layer 13, and particularly preferably about 1/6 of the content of the charge transport layer 13. Specifically, 0. O1-4Q atm% is preferred. Further, it is preferable that the intermediate layer 14 be lightly doped with a Group 3A element. The thickness of the intermediate layer 14 is preferably 0.01 to 2 μm. The intermediate layer 14 may be a laminate of two or more layers.

The charge generation layer 15 is preferably constituted by an a-3i:H(X) layer lightly doped with a Group 3A element as required. Further, in order to improve the charging ability, boron atoms may be introduced to make the material intrinsic, thereby increasing the resistance and improving carrier mobility.

The thickness of this charge generation layer 15 is preferably 2 to 15 μm.

The surface modified layer 16 is a-'Si:H(X) formed by introducing halogen atoms (X) such as hydrogen atoms and/or fluorine atoms into the a-Si layer to block dangling bonds.
It is preferable that the a-3i:Y:H(X) layer is formed by further introducing a modifying atom (Y) such as a carbon atom, an oxygen atom, or a nitrogen atom into the layer. Specifically, a −3i
: C: H(X) layer, a-3+:C:O:H(X)
Layer, a-3i: N: H(X) layer, a-5i:
N:O:H(X) layer, a-3i:C:N:H(X) layer,
Various configurations such as a-3i:C:N:O:H(X) layer can be adopted.

In the surface modified layer 16, the content ratio of modified atoms (Y) such as carbon atoms, oxygen atoms, nitrogen atoms, etc. is as follows: When the total of silicon atoms and modified atoms (Y) is lQQatm%, the modified atoms ( A ratio in which Y) is 0.5 to 9Q atm% is preferable. In addition, when the modifying atom (Y) is an oxygen atom, its content is preferably 0.5 to 7 (] atm%. In addition, modifying atoms (Y) such as carbon atoms, oxygen atoms, nitrogen atoms, etc.
When containing multiple types of modifying atoms (Y), the ratio (atm%) of carbon atoms; oxygen atoms: nitrogen atoms = 0 to 90: 0.5 to 70: 0 to 90 is preferred; ) is preferably in the range of 05 to 9Q atm%.

The thickness of the surface modified layer 16 is preferably 400 to 1 μm.

Further, a second intermediate layer may be provided between the charge generation layer 15 and the surface modification layer 16 if necessary. It is preferable that the second intermediate layer has a lower content of modified atoms (Y) than the surface modified layer 16.

It is preferable that halogen atoms (X) such as hydrogen atoms and/or fluorine atoms are introduced into each of the above layers constituting the a-5i bad sensitivity photo 10. In particular, it is important to include hydrogen atoms in the charge generation layer 15 in order to seal off dangling bonds and improve photoconductivity and charge retention. Specifically, the content ratio of hydrogen atoms is 10 to 3Q
ATM% is preferred.

The content ratio of hydrogen atoms is as follows: surface modified layer 16, intermediate layer 1
4. The same applies to the charge blocking layer 12 and the charge transporting layer 13. Further, as an impurity for controlling the conductivity type, in addition to boron, a Group 3A element such as aluminum, gallium, indium, or thallium can be used to make the conductivity type P-type.

In order to block dangling bonds during the formation of each layer constituting the a-3i bad photosensitive photosensitive material 10, a halogen atom, such as a fluorine atom, in the form of 3iF4, etc., is introduced in place of or together with a hydrogen atom, and the a-3+ :F, a-
Si:H:FSa-3i:C:F.

a-3i:C:H:F, a-3i:C:O:F, aS+
:C:O:H:F or the like may be used. In this case, the content of fluorine atoms is preferably 0.5 to IQ atm%.

Each layer constituting the a-3i ill-sensitivity lO can be formed using, for example, a glow discharge decomposition method, a sputtering method, an ion blating method, or a method in which silicon is evaporated in a state in which activated or ionized hydrogen is introduced in a hydrogen discharge tube (Unexamined Japanese Patent Publication No. 1972-
78413) or the like.

The above is an explanation for the case where the charge polarity of the a-5i photoreceptor 10 is positive, but when the charge polarity of the a-Si photoreceptor 10 is negative, the charge blocking layer 12, the charge transport layer 13, Intermediate layer 14, charge generation layer 15, surface modification layer 16
The dopant introduced into each layer may be changed to a Group 5A element (phosphorus, arsenic, antimony, bismuth, etc.). Note that the charge blocking layer 12 and the intermediate layer 14 are provided as necessary, and may be omitted.

Further, the charge transport layer 13 and the charge generation layer 15 may not have a separate layer structure but may have a single layer structure. Further, an organic photoconductive layer, a selenium photoconductive layer, a resin-dispersed photoconductive layer such as cadmium sulfide or zinc oxide may be used.

The base 11 may be formed of either conductive or insulating material. Examples of conductive materials include metals such as stainless steel, aluminum, chromium, molybutin, iridium, tellurium, titanium, platinum, and palladium, and alloys thereof. Examples of insulating materials include polyester, polyethylene, and the like. Examples include films or sheets of synthetic resins such as polycarbonate, cellulose acetate, polypropylene, polyvinylidene chloride, polystyrene, and polyamide, glass, ceramics, and paper.

When using an insulating material, it is preferable that its surface be electrically conductive treated. Specifically, for example, in the case of glass, it is conductive treated with indium oxide, tin oxide, etc., and in the case of synthetic resin films such as polyester films, it is treated with aluminum, silver, lead, nickel, gold, chromium, molybdenum, iridium, niobium, etc. , tantalum, vanadium, titanium, platinum, etc., can be subjected to conductive treatment by methods such as vacuum evaporation, electron beam evaporation, and sputtering, or by laminating with the above-mentioned metals.

The shape of the base body 11 can be selected from various shapes such as a cylindrical shape, a belt shape, and a plate shape. When forming images continuously at high speed, an endless belt or a cylindrical shape is preferable. The thickness of the base body 11 is not particularly limited, and is appropriately selected from the viewpoints of manufacturing, handling, mechanical strength, and the like.

(Development Step) The developer of the main development is transported to a development area by a developer transporting carrier, and the electrostatic charge image formed on the surface of the a-3i photoreceptor is developed in the development area.

The developer transport carrier preferably has a structure to which a bias voltage can be applied, and includes, for example, a cylindrical sleeve on which a developer layer is supported, and a plurality of magnetic poles arranged inside the sleeve. It is preferable to use a magnet made of a magnet. The rotation of the sleeve and/or the magnet conveys the developer layer on the sleeve to the development area.

In order to convey a developer layer having a uniform thickness to the development area, it is preferable to provide a thickness regulating member on the developer transport carrier upstream of the development area.

As the bias voltage applied to the developing sleeve, a DC voltage or a voltage obtained by superimposing an AC voltage on a DC voltage can be used.

(Transfer Step) The toner image on the a-3i photoreceptor obtained by development is transferred to a transfer material such as paper.

In this transfer step, an electrostatic transfer method can be preferably used. Specifically, for example, a transfer device that generates a direct current corona discharge is placed so as to face the a-3i adverse light through the transfer material, and a direct current corona discharge is applied to the transfer material from the back side. 3i The toner carried on the surface of the photoreceptor is transferred to the surface of the transfer material.

(Cleaning Step) Toner remaining on the a-3i photoreceptor without being transferred is cleaned using a cleaning device equipped with a cleaning member such as a cleaning blade placed in pressure contact with the a-3i photoreceptor.

The pressing force of the cleaning member against the a-3i sensitive light is 5 to 50 g/c from the viewpoint of improving cleaning performance.
m is preferred.

In addition, in the first stage of this cleaning process, it is preferable to add a static elimination process for eliminating static electricity from the surface of the a-3i photoreceptor in order to facilitate cleaning. This static elimination step can be performed, for example, using a static eliminator that generates AC corona discharge.

(Fixing Step) In the transfer step, the transfer material onto which the toner image has been transferred is subjected to a fixing process using a fixing device such as a heat roller fixing device, thereby forming a fixed image.

FIG. 2 is an explanatory diagram showing an example of an image forming apparatus that can perform the above image forming process. In the same figure, 10
21 is a charger, 22 is an exposure optical system,
23 is a developing device, 24 is a static elimination lamp, 25 is a transfer electrode,
26 is a separation electrode, 27 is a static elimination electrode, 28 is a cleaning device, 29 is a heat roller fixing device, 30 is a cleaning blade, and 40 is a document table. This device has an exposure optical system 2
2 is fixedly arranged, and the document table 40 is movable.

The surface of the a-3i bad sensitivity photo 10 is uniformly charged by the charger 21, and the surface of the charged a-3i bad photon 10 is subjected to image exposure by the exposure optical system 22, and is placed on the a-3i bad photosensitive photo 10. An electrostatic charge image corresponding to the original is formed.

This electrostatic charge image is developed by a developing device 23 to form a toner image.

After this toner image is neutralized by the static elimination lamp 24 and made easily transferable, it is transferred onto the transfer paper P by the transfer electrode 25. The transfer paper P is a-
It is separated from the 3i bad exposure light 10 and subjected to a fixing process in a heat roller fixing device 29, thereby forming a fixed image. On the other hand, a
-3i bad light 10 is neutralized by the static eliminating electrode 27, and is not transferred by the cleaning device 28.
The toner remaining on the photosensitive material 10 is scraped off.

The cleaning blade 30 is made of an elastic material such as hard urethane rubber with a thickness of 1 to 3 mm, and has a length substantially equivalent to the width of the a-Sig light body 10 (in the direction perpendicular to the plane of the paper in FIG. 2). It is held by a blade holder (not shown) so as to be switchable between a pressure contact position and a pressure release position.

〔Example〕

Examples of the present invention will be described below along with comparative examples, but the embodiments of the present invention are not limited to these Examples. Note that "parts" represent "parts by weight."

(1) Resin particles A (for the present invention) Made of ethylene-vinyl acetate copolymer (ethylene: vinyl acetate = 8:2), with a yield value of 13 at 20°C
Resin particles weighing 5 kg/cm2 and having an average particle size of 3.0 μm.

(2) Resin particles B (for the present invention) are made of ethylene-vinyl acetate copolymer (ethylene: vinyl acetate = 8:2) and have a yield value of 13 at 20°C.
Resin particles with an average particle size of 0.20 t-t m at 5 kg/cm2.

(3) Resin particles C (for the present invention) are made of polyurethane and have a yield value of 300 at 20°C.
kg/cm" and an average particle size of 1.0 μm.

(4) Resin particles a (for comparison) Resin particles with an average particle size of 1.0 μm, which are made of an acrylic polymer and have physical properties that do not have a yield value and are easily broken.

(5) Resin particle b (for comparison) Made of styrene-acrylonitrile copolymer, 20℃
The yield value is 700 kg/cm" and the average grain size is 0.
5 μm resin particles.

Inorganic fine particles constituting composite fine particles> (1) Inorganic fine particles A (for the present invention) Inorganic fine particles made of titanium oxide and having an average particle size of 0.2 μm.

(2) Inorganic fine particles B (for the present invention) Inorganic fine particles made of silicon carbide and having an average particle size of 0.05 μm.

Production of composite fine particles> Resin particles and inorganic fine particles in the combinations and amounts shown in Table 1 below are thoroughly stirred and mixed using a V-type mixer, and the inorganic fine particles are attached to the surface of the resin particles by electrostatic force. After that, this mixture was charged into an improved conventional impact-type pulverizer, and an impact force was applied to the mixture to produce composite fine particles in which inorganic fine particles were fixed to the surface of resin particles.

Surface observation using an electron microscope and transmission electron microscope revealed that the inorganic fine particles that had been attached to the surface of the resin particles due to electrostatic force were embedded and held in the surface of the resin particles. It was recognized that the situation was

Table 1 <Example 1> Polyester resin 100 parts Carbon black 10 parts Low molecular weight polypropylene 5 parts or more of substances were mixed, kneaded, crushed, and classified to obtain non-magnetic colored particles 1 with an average particle size of 12.0 μm. I got it.

Hydrophobic silica fine particles "Aerosil R-812J" manufactured by Nippon Aerosil Co., Ltd. are added to the colored particles 1 at a ratio of 6% by weight and composite fine particles A at 0.6% by weight, and mixed with a Henschel mixer to form Toner 1. was manufactured.

The average particle size of 103 parts of this toner and ferrite particles coated with a styrene-acrylic copolymer resin (styrene dimethyl methacrylate = 3 nia) is 80 μm.
A two-component developer according to the present invention was prepared by mixing with 97 parts of a coating carrier of m.

<Example 2> In Example 1, composite fine particles A were mixed with 0 of composite fine particles B.
．． A two-component developer B according to the present invention was produced in the same manner except that the amount was changed to 3% by weight.

<Example 3> Polyester resin 55 parts Magnetite 40 parts Low molecular weight polypropylene 3 parts Salicylic acid derivative (charge control agent) 2 parts or more of the substance was treated in the same manner as in Example 1 to form a magnetic colored material with an average particle size of 11.0 μm. Particle 2 was obtained.

To the colored particles 2, 0.4% by weight of hydrophobic silica fine particles "Aerosil R-972J" manufactured by Nippon Aerosil Co., Ltd. and 0.5% of composite fine particles B were added by weight, and mixed with a Henschel mixer. A magnetic toner 2 was produced. This magnetic toner 2 alone constituted a one-component developer C according to the present invention.

<Example 4> In Example 3, composite fine particles B were mixed with 1 of composite fine particles C.
．． A one-component developer according to the present invention was produced in the same manner except that the content was changed to 0% by weight.

Comparative Example 1 A comparative two-component developer a was produced in the same manner as in Example 1, except that the amount of composite fine particles A was changed to 0.6% by weight of the comparative fine composite particles a. .

Comparative Example 2 A comparative one-component developer was produced in the same manner as in Example 3 except that the composite fine particles B was changed to 0.5% by weight of the comparative fine composite particles. .

<Manufacture of a-5i bad sensitivity photo> A-s of the configuration shown in Fig. 1 was produced by glow discharge decomposition method.
The ig light body was manufactured as follows.

After cleaning the surface of a drum-shaped aluminum substrate with a smooth surface, it is placed in a vacuum chamber, and the gas pressure in the vacuum chamber is adjusted to 10-” Torr and evacuated. was heated and maintained at a predetermined temperature within the range of 100 to 350° C. Next, high-purity argon gas was introduced as a carrier gas, and high-frequency power at a frequency of 13.56 MHz was applied under a back pressure of 0.5 Torr. Preliminary discharge was performed for 10 minutes.

Next, a reaction gas consisting of SIH4, CH, and B2He is introduced, and the flow rate ratio is Ar:SIH4:CH.
a: B2 Hg= 1: 1: 1: 1.5
By glow discharge decomposition of a mixed gas of
/C3+H-) = 10 volume plum.

CC) = 10 atm%);
Si: C: 8 layers (CB 2 H6) / (
S IH-] = 9 volume ppm, EC) = 5 atm%
) were sequentially laminated on the substrate at a deposition rate of 6 μm/hr. The thickness of the charge blocking layer is 0.5 μm, the thickness of the charge transport layer is 10 μm, and the thickness of the intermediate layer is 1 μm.

Subsequently, the supply of gas such as CH, etc. was stopped, and 5IH4 and B 2 Hs were decomposed by discharge to form an aSi film with a thickness of 0.1 μm.
: 8 layers (however, (B2Hs) / C51H<) = 0
．． A charge generation layer having a capacity of 1 ppm) was laminated on the intermediate layer.

Next, a reformed gas consisting of 02:CH,:N2 is introduced into the vacuum chamber at a flow rate ratio of 02:CH,:N2 = 20:60:20, and is decomposed by electrical discharge to reduce the thickness to 0.
．． A surface modified layer having a thickness of 0.05 .mu.m was laminated on the charge generation layer to produce an a-5i photosensitive material having the structure shown in FIG. This is referred to as a-3i nausea photo A.

<Image formation test> Using each developer obtained as above,
The electrostatic charge image formed on the a-5i photosensitive material is developed to form a toner image, this toner image is transferred to a transfer material, the transferred toner image is fixed, and it remains on the a-3i photosensitive material after transfer. A test was conducted in which a copy image was formed by performing an image forming process including a step of cleaning the toner with a cleaning blade.

Note that developers A, B, and a, which are two-component developers, are two-component developers that include the a-3i photoreceptor A, a developing device for two-component developers, and a cleaning blade. Konica electrophotographic copying machine U-8ix 5 for
Using a modified 000 machine, a test was conducted in which copy images were formed up to 200,000 times under environmental conditions of a temperature of 20° C. and a relative humidity of 55%.

Developers C, D, and b, which are -component type developers, are developed using a single unit comprising the a-3i photoreceptor A, a non-contact developing device that applies an oscillating electric field to the development area, and a cleaning blade. Using a prototype electrophotographic copying machine for component-based developers, a test was conducted in which copied images were formed up to 200,000 times under environmental conditions of a temperature of 20° C. and a relative humidity of 55%.

Through the above tests, the following items were evaluated. The results are shown in Table 2 below.

■Cleanability Immediately after cleaning with the cleaning blade, visually observe the surface of the a-3i bad light to check for any deposits. If almost no deposits are observed, mark it as "O".
, if some deposits are observed but at a practical level,
△", if there is a lot of deposits and there is a problem in practical use, rX
I made it J.

(2) Damage to Photoreceptor The surface of the photoreceptor was visually observed to determine whether there was any damage. Note that the observation was made after the live-action test was completed.

■Image Density Measure the reflection density using a Konica ■Sakura densitometer, and if the reflection density is 1.25 or more, it is "O", 1
．． A case of 1 or more and less than 1.25 was given as "ΔJ", and a case of less than 1.1 was given as "x".

■ Visually observe the black spot copy image to check for the presence or absence of black spots caused by damage to the surface of the a-3i negative light. If there are almost no black spots, it is rated "O," and if there are some black spots, it is rated "O." A case where it is at a practical level is marked as "△", and a case where there are many black spots and there is a problem in practical use is marked as "x".

As is clear from Table 2 above, the developer A-
According to D, the surface of the a-Si photoreceptor can always be maintained in a good condition, and good IJ-ning properties can be exhibited. Further, stable images with high image density can be formed over 200,000 times. Furthermore, black spots caused by damage to the surface of the a-5i photoreceptor are also intolerable.

On the other hand, in the comparative developers a and b, the resin particles constituting the composite fine particles are hard, so the composite fine particles sandwiched between the cleaning blade and the a-3i bad exposure light are destroyed. Due to the free inorganic fine particles and fine resin particles, the IJ-ing property was deteriorated and the image density was early reduced.

〔Effect of the invention〕

As explained in detail above, according to the developer of the present invention,
Since the resin particles that form the core of the composite fine particles have a yield value at 20°C within a specific range and have tenacious physical properties, the cleaning member placed in contact with the a-3i ill-sensing light with a relatively large pressing force When cleaning the toner, even when the composite fine particles sandwiched between the cleaning member and the a-3i bad exposure light are subjected to a large pressure contact force, the resin particles forming the core of the composite fine particles are appropriately deformed. It exerts a cushioning effect and cannot be destroyed.

Therefore, there is no risk that the surface of the a-Si photoreceptor will be scratched by the inorganic fine particles present on the surface of the composite fine particles, and damage to the surface of the a-3i photoreceptor can be effectively prevented, and the inorganic fine particles Furthermore, fine powder of resin particles is not generated, and as a result, images with sufficient image density and without black spots can be stably formed many times without causing cleaning defects.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a specific example of the structure of the a-51g light body, and FIG. 2 is a schematic diagram showing an example of an image forming apparatus. 10...a-5i photoreceptor 11...Base 12.
... Charge block o, 7 King layer 13... Charge transport layer 14... Intermediate layer 15.
...Charge generation layer 16...Surface modification layer 21...
・Charging device 23...Developing device 25...Transfer electrode 29...Heat roller fixing device 30...Cleaning plate 40...Original table 22...Exposure optical system 24...Static elimination lamp 28 ...Cleaning device door

Claims (1)

[Claims] Forming an electrostatic charge image on an amorphous silicon photoreceptor and developing this electrostatic charge image with a developer to form a toner image,
In the developer used in the image forming process that includes the step of cleaning the toner remaining on the amorphous silicon photoreceptor after transferring the toner image to the transfer material, the toner constituting the developer contains at least a resin and a colorant. and a yield value of 10 at 20°C.
~500 kg/cm^2, containing composite fine particles in which inorganic fine particles with an average particle size of 0.01 to 1 μm are fixed to the surface of resin particles with an average particle size of 0.1 to 7 μm. Characteristic developer.