JPS62180376A - Image forming method - Google Patents

Abstract

PURPOSE:To keep the excellent fluidity of recovered toner for a long period when it is reused by using a latent image carrier which has a photosensitive body with >=160 Vickers hardness and using toner formed by adding and mixing fluidizing agent particulates of >=25mmu in primary particle size with toner particle powder. CONSTITUTION:The toner obtained by adding and mixing fluidizing agent particulates of >=25mmu in primary particle size to the toner particle powder is supplied to the latent image carrier which has the photosensitive layer with >=160 Vickers hardness to develop is latent image into an image, and toner which is supplied to the latent image carrier, but not consumed as part of the visible image actually is recovered and used for development again to form a next image. The latent image carrier 1 is constituted by forming a blocking layer 11B of aluminum oxide on the outer peripheral surface of a drum-shaped base 11A of metal such as stainless steel and further providing the photosensitive layer made of amorphous silicon on the blocking layer 11B. The fluidizing agent preferably has 30-50mmu primary grain size.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming method for forming an image by visualizing an electrostatic latent image or a magnetic latent image using toner.

[Technology background]

For example, an image forming method using electrophotography includes a step of forming an electrostatic latent image on a latent image carrier, a developing step of visualizing this electrostatic latent image with toner to form a toner image, and a step of converting this toner image into a toner image. In the fixing step, the toner image formed in the developing step may be fixed directly on the support, but usually it is transferred to another support such as transfer paper and then fixed. I have to.

In the electrostatic latent image development process, a sufficient amount of toner is supplied to the development area to develop the electrostatic latent image and form a toner image, but all of the toner constituting this toner image is The toner is not transferred to transfer paper, and a portion of the toner usually remains on the latent image carrier. Therefore, it would be very economical to collect and reuse the toner that was supplied to the latent image carrier but was not actually consumed as part of the visible image. An image forming method has been proposed that employs a so-called recycling system in which a cleaning section is provided on the downstream side of the toner to collect the toner, and the collected toner is again supplied to the developing section.

However, in order to form images of good quality, it is necessary for toner to have high fluidity, and from this point of view, fluidizing agents such as silica particles are mixed into toner powder. .

[Problem that the invention seeks to solve]

Conventionally, the smaller the particle size of the fluidizing agent, the smaller the mixing ratio in the toner powder to obtain good fluidity, and the smaller the particle size of the fluidizing agent, the less damage to the latent image carrier. As a fluidizing agent, the primary particle size is approximately 20 ■p or less are used (see JP-A-46-5782 and JP-A-48-47346).

However, when an image is formed using a toner containing a fluidizing agent with such a small particle size by an image forming method that employs a recycling system, the collected toner particles are repeatedly used in the image forming process. As a result, the toner particles are frequently subjected to mechanical external forces, and as a result, there is a significant tendency for the fluidizing agent that should be present on the surface of the toner adhesion to become embedded in the toner particles. As a result, the fluidity of the toner decreases, and the rise of the charge amount of the toner during development becomes slow, resulting in a decrease in the amount of toner adhering to the latent image, or fogging occurs in the resulting image, resulting in an image with good quality. is difficult to form stably.

One possible way to eliminate these problems is to use a fluidizing agent with a large particle size. However, as the particle size of the fluidizing agent becomes large, the selenium-based Since the latent image carrier having a photosensitive layer is easily subjected to excessive polishing by a fluidizing agent, scratches such as minute recesses are generated on the latent image carrier, and toner particles are trapped in the minute recesses. There is a problem in that the particles are buried and cannot be cleaned, and in the formation of the next image, this is transferred and fixed to the transfer paper and appears as dots.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and an object thereof is to obtain good fluidity for a long period of time even when toner collected by a recycling system is used for development again, and to provide a latent image carrier with a An object of the present invention is to provide an image forming method capable of stably forming an image of excellent image quality without generating dot-like stains caused by damage to the image forming apparatus.

Means for Solving Problem C] The image forming method of the present invention is a method of forming an image by supplying toner to a latent image carrier using a recycling system, in which the latent image carrier has a Vickers hardness of 160 or more. The toner is characterized in that the toner is prepared by adding and mixing a particulate fluidizing agent having a primary particle diameter of 251p or more to toner particles.

According to this method, since the primary particle size of the fluidizing agent mixed with the toner particle powder is 25 mm or more, the fluidizing agent is not embedded in the toner particles ((therefore, the recycling system Even when the collected toner is subjected to development again, stable high fluidity can be obtained for a long period of time, and as a result, the charge amount of the toner rises sharply during development, making it possible to repeatedly achieve good development. Deep,
Since the image carrier has a photosensitive layer with a Pinkers hardness of 160 or more, the surface of the latent image carrier is harder than that of a selenium-based material, and therefore the fluidizing agent has a large primary particle size. Despite this, damage to the latent image carrier is less likely to occur, and as a result, the resulting image does not have spot-like stains caused by damage to the latent image carrier, making it possible to form a good image. can.

The present invention will be explained in detail below.

In the present invention, a latent image carrier having a photosensitive layer having a Pinkers hardness of 160 or more is formed by adding and mixing a fine particle fluidizing agent with a primary particle diameter of 25-〃 or more to toner particle powder. supplying toner, thereby developing the latent image to form an image; and collecting toner supplied to the image carrier but not actually consumed as part of the visible image; The toner is again subjected to development to form the next image.

The latent image carrier used in the present invention has a Pinkers hardness of 160.
Specific examples of materials constituting the photosensitive layer include amorphous silicon, amorphous silicon germanium, amorphous silicon tin, or those containing carbon, nitrogen, oxygen, etc. Further, these may be doped with an element of group 111a of the periodic table or an element of group Va of the periodic table. Among these, amorphous silicon is particularly suitable.

If the Vickers hardness of the photosensitive layer is too low, the photosensitive layer is likely to be scratched by a fluidizing agent or the like, and the life of the photosensitive layer will be shortened.

In a specific example of a latent image carrier in which the photosensitive layer is made of, for example, amorphous silicon, as shown in FIG. A latent image carrier 1 is constructed by providing a blocking layer 11B made of, for example, aluminum oxide, and providing a photosensitive layer 12 made of amorphous silicon on this blocking layer 11B. The blocking layer 11B is provided as necessary to prevent charge from being injected into the photosensitive layer 12 from the base 11A.

The photosensitive layer 12 can be formed using a thin film manufacturing technique such as a glow discharge method, a sputtering method, an ion blating method, or a vapor deposition method. The thickness of this photosensitive layer 12 is
Usually, it is preferable that it is 5 to 50 p1.

The blocking layer 11B is formed on the base 11 made of metal.
A method of forming the surface of A by oxidizing means such as anodizing, oxidizing, plasma oxidizing, etc. in a vacuum chamber, such as silicon oxide, aluminum oxide, chromium oxide, titanium oxide, zircon oxide, silicon nitride, An insulating substance such as magnesium fluoride or zinc sulfide is applied to the base 11A.
This can be carried out using a method such as a method of forming by adhering and depositing on the surface of.

In the present invention, an image is formed by a recycling system in which toner that has been supplied to a latent image carrier but is not actually consumed as part of a visible image is collected and the collected toner is again used for development.

A concrete example of the recycling system is shown in FIGS. 2 and 3. In the example shown in FIG. 2, 20 is a collection drum, and this collection drum 20 is a drum-shaped latent image carrier (
The collecting drum 2 is coaxially supported with the latent image carrier through a partition wall (not shown) at one end side (not shown).
A plurality of magnets 21 are fixedly provided inside the collecting drum 20 along its outer periphery, and a conveyor belt 22 is suspended around the outer periphery of the collection drum 20 .

23 is a cleaning mechanism, and this cleaning mechanism 23 extends so as to face the cleaning area of the latent image carrier and also to face the collection drum 20.

In this cleaning mechanism 23, the toner remaining on the latent image carrier is scraped off and collected by, for example, a blade, and the collected toner is supplied to the exit 25 side by a screw conveyor 24 provided inside. be done.

26 is a developing mechanism, and this developing mechanism 26 includes a rotating drum-shaped magnetic brush mechanism 27 arranged to face the developing area of the latent image carrier and also face the collection drum 20;
It has a developer stirring mechanism 28 and a toner receiving and distributing mechanism 29 that receives the collected toner and distributes it into the developing mechanism 26, and the conveyor belt 22 has a collecting drum 20 and a magnetic brush mechanism. After passing through the gap between the toner collecting drum 20 and the outlet 27 of the cleaning mechanism 23, the toner is transferred to the toner receiving and distributing mechanism 29 of the developing mechanism 26 via the gap between the collecting drum 20 and the outlet 25 of the cleaning mechanism 23.
It is suspended between the collecting drum 20 and rollers 3G and 31 so as to reach this point. 27a is a rotating sleeve, and 27b is a magnet.

In this example, when the conveyor belt 22 is moved, the conveyor belt 22 moves between the collecting drum 20 and the magnetic brush mechanism 2.
7, a magnetic brush of the developer is formed on the conveying belt 22 by the magnetic brush mechanism 27, and this magnetic brush is transferred to the cleaning mechanism 23 as the conveying belt 22 moves. The toner collected from the latent image carrier by the cleaning mechanism 23 and supplied to the exit 25 side by the screw conveyor 24 is lifted up by the magnetic brush on the conveyor belt 22, and the magnetic brush is moved by the movement of the conveyor belt 22. The toner picked up is conveyed to the toner receiving and distributing mechanism 29, where the toner is stored in the developing mechanism 26, and the collected toner is again used to develop the latent image on the latent image carrier.

On the other hand, in the example shown in FIG. 3, 41 is a developing mechanism;
2 is a cleaning mechanism; 43 is a toner receiving and distributing mechanism;
44 is a magnetic brush mechanism, 45 is a latent image carrier, 46 is a screw conveyor, 47 is a first screw, and 48 is a second screw.
and the second screw 48, the screw conveyor 46
The toner is supplied to the toner receiving and distributing mechanism 43. That is, the first screw 47 and the second screw 48 each have a rotating shaft inside and a blade spirally provided along the rotating shaft. As the rotating shaft rotates, the toner is sequentially pushed up by the blades and sent to the second screw 48,
In this second screw 48, the first screw 4
7, the toner is sequentially fed in the horizontal direction and supplied to the toner receiving and distributing mechanism 43, and the collected toner is again used to develop the latent image on the latent image carrier 45.

The toner used in the present invention contains a colorant in a binder,
For example, fine particulate fluidizing agent with a primary particle size of 25 mu or more is added and mixed to toner particle powder with an average particle size of about 5 to 157 zs, which is dispersed with other additives used as necessary. That's what happens. Here, the primary particle diameter of the fluidizing agent refers to the particle diameter of the primary particles (particles separated into individual unit particles) of the fluidizing agent in the form of fine particles.
Specifically, it can be determined by converting the surface area determined by, for example, the BET method.

The fluidizing agent is in the form of fine particles with a primary particle size of 25u or more, preferably a primary particle size of 30 to 50u. When this primary particle size is too small, when forming an image using a recycling system, the fluidizing agent is significantly embedded in the toner particles, resulting in a decrease in the fluidity of the toner and the amount of charge of the toner in the developing process. The rise of the image becomes slow, the amount of toner adhering to the latent image decreases, and the image quality deteriorates. When the primary particle size of the fluidizing agent is too large, the abrasive force applied to the latent image carrier becomes large (as a result, the surface of the latent image carrier tends to be easily damaged; for example, if the surface of the latent image carrier is If scratches such as minute recesses occur, toner particles may remain in the small recesses because the toner is not sufficiently cleaned during the cleaning process.
These toner particles may be transferred and fixed on the transfer paper in the formation of the next image, and in this case, dot-like stains occur in the resulting image.

In addition, the usage ratio of the fluidizing agent in the toner is 0.5~
It is preferably 2.0% by weight; if this proportion is too small, fluidity tends to be insufficient, while if this proportion is too large, the surface of the latent image carrier tends to be easily damaged.

Such fluidizing agents include, for example, fine particles of oxides such as silica, alumina, titania, calcium oxide, magnesium oxide, barium oxide, beryllium oxide, cerium oxide, iron oxide, strontium titanate, and fine particles of these oxides. Examples include those that have been subjected to hydrophobization treatment.

In particular, when using a fluidizing agent that has been subjected to water-repelling treatment, the moisture resistance of the fluidizing agent is improved, and therefore a stable fluidizing effect can be obtained even in a high-humidity atmosphere.

Such hydrophobization treatment involves, for example, reacting fine particles of the oxides mentioned above with a hydrophobization treatment agent such as dialkyldihalogenated silane, trialkylhalogenated silane, alkyltrihalogenated silane, hexaalkyldisilazane, etc. at high temperature. This can be done by letting

Specific examples of fluidizing agents that can be used in the present invention include the following.

"Aerosil R-809J (hydrophobic silica, primary particle size: 305g, manufactured by Nippon Aerosil Co., Ltd.)"Aerosil T
-805J (hydrophobic titania, primary particle size: 30u, manufactured by Nippon Aerosil Co., Ltd.) Examples of the binder for the toner used in the present invention include styrene and its substituted products such as polystyrene, polyp-chlorostyrene, and polyvinyltoluene. Polymer, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-
Ethyl acrylate copolymer, styrene-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 Styrenic copolymers such as ethyl ether copolymer, styrene-vinylmethylketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, polyvinyl chloride, Vinyl acetate, polyethylene, polypropylene, silicone resin, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenolic resin, xylene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum Examples include resin. These resins can be used alone or in combination of two or more.

The toner used in the present invention may contain a colorant and other additives used as necessary. Examples of other additives used as necessary include a magnetic material, a charge control agent, and an offset prevention agent. , and other property improvers, which are commonly used as toner ingredients, are used as additives.

Examples of the coloring agent include Carbon Bra 7-li, Nigrosine dye (C, 1, Na50415B), Aniline Blue (C, 1, Magnetic 50405), Calco Oil Blue (C, 1, Fish Azoic Blue 3), and Chrome Yellow. (C,1,1m14090), Ultramarine Blue (C,1,l1h77103), DuPont Oil Red (C,1,Na26105), Quinoline Yellow (
C,l 11&L47005), methylene blue chloride (C,l.

52015), phthalocyanine blue (C, 1, Na
74160), malachite green off-salate (C
01, Ik42000), Lamp Plack (C, 1,
Na7?266), Rose Bengal (C,1, Na45
435), mixtures thereof, and others. The colorant is preferably contained in a sufficient proportion to form a visible image of sufficient density, and is usually added to the binder 1.
The amount is preferably about 1 to 20 parts by weight per 00 parts by weight; Examples of the magnetic material include metals or alloys exhibiting ferromagnetism such as iron, cobalt, and nickel, including ferrite and magnetite, or compounds containing these elements; Alternatively, alloys that do not contain ferromagnetic elements but become ferromagnetic through appropriate heat treatment, such as Heusler alloys that contain manganese and copper, such as manganese-copper-aluminum, manganese-copper-tin, etc. alloys, or chromium dioxide, and others. These magnetic substances are used in the form of fine powder with an average particle size of 0.1 to 1 μm, and the ratio thereof is preferably 20 to 70 parts by weight, more preferably 40 to 70 parts by weight per 100 parts by weight of toner.

Examples of negatively chargeable charge control agents include those disclosed in JP-A-57-141452 and JP-A-58-76.
45, JP 58-111049, JP 58-185653, JP 57-167033
2:1 type metal-containing azo dyes disclosed in Japanese Patent Publication No. 44-6397, etc.; for example, JP-A-57-104
940, JP 57-1115.41, JP 57-124357, JP 53-1277
Metal complexes of aromatic oxycarboxylic acids and aromatic guicarboxylic acids disclosed in Japanese Patent Publication No. 26, etc.; for example, JP-A No. 5
Examples include sulfonylamine derivatives of copper phthalocyanine dyes, sulfonamide derivative dyes of copper phthalocyanine, and sulfonamide and sulfonic acid or sulfonate derivative dyes of copper phthalocyanine, which are disclosed in Publication No. 2-45931. Examples of chargeable materials include, for example, JP-A-49-51951;
Quaternary ammonium compounds disclosed in JP-A-52-10141, etc.; for example, JP-A-56-1146;
Alkylpyridinium compounds and alkylpicolinium compounds disclosed in Publication No. 1, JP-A-54-158932, US Pat. No. 4,254,205, etc.;
Examples include nigrosine dyes such as nigrosine SO and nigrosine EX; examples include addition condensates disclosed in Japanese Patent Publication No. 49-80320.

As the offset prevention agent, for example, polyethylene,
Low softening point olefin polymers or copolymers such as polypropylene, high melting point paraffin waxes such as microwax and Fischer-Tropsch wax, liquid paraffins that are saturated or unsaturated paraffins that are liquid at room temperature, such as methyl silicone meth, phenyl silicone varnish. aliphatic fluorocarbon compounds such as low polymerization compounds of tetrafluoroethylene and hexafluoropropylene, such as lower alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids, higher alcohol esters of fatty acids, fatty acids and polyhydric Fatty acid esters such as alcohol partial esters and mixed esters and their partially saponified products, alkylene bis fatty acid amides, higher fats 61, fatty acid metal salts, higher alcohols, such as those described in JP-A-55-124428. Examples include fluorine-containing surfactants. Such offset inhibitors can be used alone or in combination of two or more, and the usage ratio thereof is preferably, for example, 1 to 20% by weight, more preferably 1 to 10% by weight, based on the binder. be.

The toner used in the present invention may be mixed with a carrier to form a two-component developer to form an image, or when the toner contains a magnetic material, it may be used as a single-component developer to form an image. It may also be used for formation.

The carrier that can be used when forming a two-component developer is not particularly limited, and examples include reduced iron powder, ferrite powder, and resins such as styrene-acrylic resin, silicone resin, and fluorine resin. It is possible to use one in which magnetic particles are dispersed in a binder made of these resins, and the like. The average particle size of the carrier is usually lO~30
It is preferably 0n, more preferably 30-2
It is 00-.

Further, the developing method is not particularly limited, and various known developing methods can be employed. Specifically, for example, (a) -
For example, a magnetic brush of a component or two-component developer is carried on a developer transport carrier in a state where the layer thickness is larger than the gap in the developing area, and this magnetic brush is carried into the developing area and the latent image is rubbed by the magnetic brush. (b) A contact magnetic brush method in which toner particles or particle groups in a magnetic brush are attached to a latent image for development; (b) a magnetic brush of a component or two-component developer is The magnetic brush is carried in a small state on a developer transporting carrier, and the toner particles or particle groups in the magnetic brush are caused to fly while the toner particles or particle groups in the magnetic brush are caused to fly. An image can be formed by employing a developing method such as a jumping magnetic brush method or (c) cascade method in which toner particles or particle groups are attached to a latent image and developed.

〔Example〕

Examples of the present invention will be described below, but the present invention is not limited thereto. Note that "parts" represent parts by weight.

Example 1 (Production of binder) 299 g of terephthalic acid and polyoxypropylene (2,
2) 211 g of -2,2-bis(4-hydroxyphenyl)propane and 82 g of pentaerythritol were placed in a round-bottomed flask equipped with a thermometer, a stainless steel stirrer, a glass nitrogen gas inlet tube, and a down-flow condenser. and set this flask on the mantle heater.
Nitrogen gas was introduced from the nitrogen gas inlet tube to raise the temperature while keeping the inside of the flask in an inert atmosphere.Next, 0.5g of dibutyltin oxide was added, and the reaction was allowed to occur at a temperature of 200°C while monitoring the reaction at the softening point. The chloroform insoluble content is 17%, JIS K 1351-19.
60! A polyester having a ring and ball softening point of 131° C. was obtained. This will be referred to as "binder l".

(Manufacture of toner) 0 parts Binder Htoo parts 0 carbon blank "Mogul L" (manufactured by Caposoto) 10 parts O low molecular weight polypropylene "Viscol 660 P J (manufactured by Sanyo Chemical Industries, Ltd.) 3 parts or more of the substances are melt-kneaded and cooled. A toner particle powder having an average particle diameter of 10 m was obtained by a method of post-pulverization and classification.This will be referred to as "toner particle powder a."

To this toner particle powder a, a fluidizing agent rR-809J (silica fine particles hydrophobized with hexamethyldisilazane, primary particle size: 30 mm, manufactured by Nippon Aerosil Co., Ltd.) was added to the toner particle powder a in a ratio of 1. They were added and mixed in a proportion of 2% by weight, thereby obtaining a toner.

This is referred to as "toner 1".

Next, 4 parts by weight of this toner 1 and 96 parts by weight of a carrier made of resin-coated iron powder were mixed to prepare a developer. This is referred to as "developer l".

Using this developer l, amorphous silicon (Vickers hardness: 800 (kg/+++n+”at40
An electrophotographic copying machine comprising a latent image carrier having a photosensitive layer and a toner recycling system consisting of
A photo test was conducted using U-Bix 5000J (manufactured by Konishiroku Photo Industry Co., Ltd.), and the toner static bulk density, toner charge amount, and image quality were investigated at the initial stage of image formation and after 100,000 image formations.

The static bulk density of toner evaluates the fluidity of the toner, and the higher the fluidity, the higher the static bulk density. Specifically, the static bulk density of Tona 4 was determined using a powder compaction tester "Tap Denser" (manufactured by Seishin Enterprise Co., Ltd.).
100 meters from above in a container with a diameter of 28 m + layer and a volume of 100 m.
Loosely fill the toner through a mesh sieve, measure the weight M (mg) at this time, and divide this weight M (mg) by the volume 100 d, which is the value M/1100 (a/d), which is the static bulk density. .

Further, the value of the amount of charge was measured by a known blow-off method. Specifically, it can be determined, for example, using a measuring device shown in FIG. In the figure, 51 is a mesh screen, 52 is a metal container, 53 is a compressed gas inlet,
54 is a voltmeter, and 55 is a capacitor. Using this device, the amount of charge is measured as follows. That is, by placing the developer on the mesh screen 51 and blowing high-pressure gas through the compressed gas blowing port 53, only the toner is blown away and the carrier is separated, and the charge remaining on the carrier is read by the voltmeter 54 to determine the amount of charge. seek the fall of

These results are shown in Table 1 below. In Table 1,
In the "Image quality" column, "○" indicates that no fogging is observed and the image quality is clear and good, and "x" indicates that fogging is occurring and the clarity is poor.

Example 2 A fluidizing agent rT was added to the toner particle powder A obtained in Example 1.
-805J (titania fine particles hydrophobized with hexamethyldisilazane, primary particle size: 30 m#, manufactured by Nippon Aerosil Co., Ltd.) at a ratio of 1.2 to toner particle powder a
A toner was obtained by adding and mixing them in a proportion of % by weight. This will be referred to as "toner 2".

Next, a developer was prepared using this Toner 2 in the same manner as in Example 1. This will be referred to as "Developer 2".

Using this developer 2, a live photographing test was conducted in the same manner as in Example 1, and the initial image formation and the number of image formation were 100.
The static bulk density of the toner, the amount of charge of the toner, and the image quality after 000 cycles were investigated. The results are shown in Table 1 below.

Comparative Example 1 A fluidizing agent rR was added to the toner particle powder A obtained in Example 1.
-972J (silica fine particles hydrophobized with dimethyldichlorosilane, primary particle size: 16, manufactured by Nippon Aerosil Co., Ltd.) was added and mixed at a ratio of 0.8% by weight to toner particle powder a. Got toner. This is referred to as "comparison toner 1."

Next, a developer was prepared in the same manner as in Example 1 using this comparative toner I. This is referred to as "comparative developer 1."

Using this comparative developer 1, a live photo test was conducted in the same manner as in Example 1, and the initial image formation and the number of image formation were 10.
The static bulk density of the toner, the amount of charge of the toner, and the image quality after 0,000 cycles were investigated. The results are shown in Table 1 below.

Comparative Example 2 A fluidizing agent rR was added to the toner particle powder A obtained in Example 1.
-812J (silica fine particles hydrophobized with hexamethyldisilazane, primary particle size near 1μ, manufactured by Nippon Aerosil Co., Ltd.) is added and mixed at a ratio of 0.4% by weight to toner particles a to form a toner. I got it. This is referred to as "comparison toner 2."

Next, a developer was prepared in the same manner as in Example 1 using this comparative toner 2. This is referred to as "comparative developer 2."

Using this comparison developer 2, a live photo test was conducted in the same manner as in Example 1, and the initial image formation and the number of image formation were 10.
The static bulk density of the toner, the amount of charge of the toner, and the image quality after 0,000 cycles were investigated. The results are shown in Table 1 below.

As can be understood from the results in Table 1, Toner 1 and Toner 2 have been successfully used for many times in image formation using a toner recycling system, with small changes in static bulk density and small changes in charge amount. It is possible to stably form images of high quality.

On the other hand, according to Comparative Toner 1 and Comparative Toner 2, when forming an image using a toner recycling system, the static bulk density and charge amount were sufficient and the image quality was good at the initial stage of image formation, but the number of times the image was formed was is 100
．． When the number of times reaches 000 times, the static bulk density and the amount of charge become large (changed), and the image quality deteriorates considerably, and in the end, good ii! iii! f images are stably formed over many times. was difficult.

Furthermore, when Comparative Toner 1 and Comparative Toner 2 were observed using a W4 microscope after the number of image formations reached 100,000 times, it was found that in both toners, the fluidizing agent was significantly embedded in the toner particles. On the other hand, when the carriers in Comparative Developer 1 and Comparative Developer 2 were observed under a microscope after the number of image formations reached 100,000 times, it was found that there was very little toner substance adhering to the particle surface of both carriers. Therefore, no decrease in the triboelectric charging properties of the carrier was observed.

In this way, Comparative Toner 1 and Comparative Toner 2 contain a fluidizing agent with a too small primary particle size, so the toner is frequently subjected to mechanical external force due to repeated use in image formation using a toner recycling system. When this occurs, the fluidizing agent becomes significantly embedded in the toner particles, resulting in a decrease in the fluidity of the toner and deterioration of image quality, making it difficult to stably form good images over many times. It is.

〔Effect of the invention〕

According to the image forming method of the present invention, since the primary particle size of the fluidizing agent added to and mixed with the toner particles is 25 μ or more, the fluidizing agent is unlikely to be embedded in the toner particles, and therefore is recycled. Even when the toner collected by the system is used again for development, stable high fluidity can be obtained for a long period of time.As a result, the toner has an excellent rise in the amount of charge during development, making it possible to repeatedly achieve good development. Moreover, since the latent image carrier has a photosensitive layer with a Vickers hardness of 160 or more, the surface of the latent image carrier is harder than that of a selenium-based material, and therefore the fluidizing agent has a hardness of its primary particle diameter. Even though the latent image bearing member is large, damage to the latent image bearing member is less likely to occur, and as a result, the resulting image does not have spot-like stains caused by damage to the latent image bearing member, resulting in a good image. can be formed.

[Brief explanation of drawings]

FIG. 1 is an explanatory sectional view showing an example of a latent image carrier, FIGS. 2 and 3 are explanatory views each showing an example of a recycling system, and FIG. 4 is an explanatory view showing an example of a charge amount measuring device. FIG. 11A...Substrate 11B...Blocking layer 12...Photosensitive layer 1...Latent image carrier 20...Recovery drum 21...Magnet 22...
・Transport belt 23...Cleaning mechanism 24...Screw conveyor 25...Outlet 26...Developing mechanism 27
...Magnetic brush mechanism 28...Developer stirring mechanism 2
9... Toner receiving and distributing mechanism 30. 31... Roller 27a... Rotating sleeve 27b... Magnet 41... Developing mechanism 42... Cleaning mechanism 43... Toner receiving and distributing mechanism 44... Magnetic brush mechanism 45...Latent image carrier 4
6...Screw conveyor 47...First screw 48...Second screw 51...Mesh screen 52...Metal container

Claims (1)

[Claims] 1) A method of forming an image by supplying toner to a latent image carrier using a recycling system, wherein the latent image carrier has a photosensitive layer having a Vickers hardness of 160 or more. As the toner, the toner particles have a primary particle diameter of 2.
An image forming method characterized by using a material obtained by adding and mixing a fluidizing agent in the form of fine particles of 5 mμ or more.