JPS59184363A - Developing method - Google Patents

Abstract

PURPOSE:To prevent generation of contamination of the surface by controlling an applied layer which consists of a soft material and a hard wall forming material for covering said material, and is obtained by applying a microcapsule insulating nonmagnetic toner having a specified electrostatic charging characteristic to a toner carrying body, to a thinner thickness than a gap between a latent image holding body and the toner carrying body, carrying it to a developing part, and developing it under an alternating electric field. CONSTITUTION:A microcapsule toner whose particle diameter is about 3-20mu is obtained by covering the circumference of a soft solid core containing 1- 30wt% coloring and dyeing pigment, to a thickness of 0.01-2mu by a hard material. An for a friction charging charge quantity of the microcapsule, that of 1-50mu coul/g is used by measuring it by the two-component method. As for the soft material, that which is twined easily to a fiber of usual paper by pressure of about 20kg/cm<2> wire pressure is desirable, and as for the hard material for covering the circumference of the soft solid core, for instance, polystyrene, poly-p-chlorostyrene, chlorinated paraffin, wax, fatty acid, etc. are used singly or by mixing them. In this way, a development is executed by applying an alternating electric field to the toner in the developing part.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for developing an electrostatic latent image formed on the surface of a latent image carrier, in particular a method for developing an electrostatic latent image formed on a developer (toner) carrier by forming a thin and uniform toner layer on the developer (toner) carrier. It's about how to do it.

Conventionally, the following methods are known as developing methods using a one-component nonmagnetic toner.

For example, in an electrostatic image development method in which an electrostatic image on the surface of the latent image carrier is developed by placing a developer carrier holding a developer on the surface facing the latent image carrier, the developer stored in the developer storage means is When pumping up the developer under the developer carrier onto the developer carrier, vibration is applied to the developer in the pumped-up portion to activate it and form a developer layer of a predetermined thickness on the surface of the developer carrier. There is a developing method in which the film is formed and then subjected to development.

An example of this developing method is shown in FIG. In the figure, in the development process, the toner supplied by a toner supply member 10 is moved by vibration members and vibration generating means 6 and 7, collides with the toner carrier 2, and is charged by friction between the toner carrier 2 and the toner carrier 2. When the toner is carried on the toner carrier by the Coulomb force and brought close to the electrostatic latent image carrier, the toner is transferred from the surface of the toner carrier 2 to the surface of the electrostatic latent image carrier due to the electric field caused by the electrostatic image. Development ends. After the development is completed, the toner remaining on the toner carrier is scraped off by the cleaning blade 9.

In addition, there is a rotatable magnetic roller that adsorbs a magnetic carrier to charge the one-component non-magnetic toner particles to form a magnetic brush, and a rotatable magnetic roller that transfers the toner particles of the roller and charges the electrostatic image carrier on the electrostatic image carrier. It has a developing roller for developing an image, maintains a gap between the electrostatic image holder and the developing roller in the developing section, and sets the gap length to be larger than the thickness of the toner coating layer on the developing roller. There is a method to develop an electric image.

An example of this developing method is shown in FIG. In the figure, during development, the carrier particles of the magnetic brush 112 are transferred to the toner 113.
Frictional charging causes toner to adhere to the carrier surface using Coulomb force. The attached toner is on the developing roller 111
The applied electric field causes the toner to adhere uniformly to the surface of the developing roller 111, and when this toner is brought close to the electrostatic latent image holder 101, the toner is terminated by the electric field of the electrostatic latent image.

The movable developer carrying means carries and transports the developer and supplies it to the latent image holding member, the developer replenishing means receives the developer from the developer replenishing means, and the movable developer carrying means receives the developer from the developer replenishing means. A movable applicator for applying a developer, which has a fiber brush that carries the developer on its surface, and is in contact with the movable developer carrier and in the same direction as the movable developer carrier at this abutting portion. There is a method in which toner is uniformly applied to the surface of the movable developer carrier means using a movable coating means that moves at a higher speed than the movable developer carrier means, and development is carried out by bringing this coated layer close to the electrostatic latent image area. be. An example of this developing method is shown in the third example.
As shown in the figure. In the figure, development is performed by adsorbing the toner 207 onto the surface of the fiber brush 206 using Coulomb force generated by frictional charging between the fiber brush 206 and the toner 207 present on the surface of the application roller 204, and then moving this brush onto the developing roller 203. By applying an electric field between the coating roller 204 and the developing roller 203, the toner is transferred from the surface of the fiber brush 206 to the developing roller 203.
transfers uniformly to the surface of After that, this developing roller 2
By the electric field formed by the electrostatic latent image 03 on the surface of the electrophotographic photoreceptor 201, the toner on the surface of the developing roller is transferred to the surface of the electrostatic latent image, and development is completed.

Compared to conventional developing methods using magnetic component toners, these methods apply stronger pressure when applying the toner to the toner carrier, so waxes such as polyethylene and paraffin, polybdenum, polyisobutylene, etc. When using a toner with a soft material as a binder, the toner adheres to the toner carrier by force other than electrostatic force, and the toner on the toner carrier is brought close to the electrostatic latent image area during development. Also, sufficient density cannot be obtained because the toner is difficult to develop into an electrostatic latent image, and frictional charging occurs between the toner firmly adhered to the toner carrier and the newly replenished toner. Toners with a very low amount of triboelectric charge exist, and such toners have the disadvantage of adhering to non-latent image areas and causing so-called background staining.

An object of the present invention is to provide a developing method that improves the above-mentioned drawbacks.

Another object of the present invention is to provide a developing method in which toner does not adhere firmly to a toner carrier.

Still another object of the present invention is to provide a developing method that provides sufficient image density without staining the background area.

The object of the present invention is to provide a latent image holding body that holds a latent image on its surface;
A toner carrier carrying an insulating non-magnetic toner is arranged with a certain gap in a developing section, and a microcapsule insulating non-magnetic toner made of a soft material and a hard wall-forming material covering it is placed on the toner carrier. The coated layer is regulated to a thickness thinner than the gap and transported to a developing section.
When measured using the component method, the absolute value of tripo is 5 to 50μc
This is achieved by developing the toner of oul/A while applying an alternating electric field in the developing section.

The particle size of the microcapsule toner that can be used in the present invention is 3 to 20 microns (preferably 5 to 10 microns). The toner has a soft solid core containing 1 to 30 wt% (preferably 5 to 15 wt%) of a coloring dye and pigment, and a hard material surrounding it with a thickness of 0.01 to 2 μm (preferably 0.1 to 0.3 μm). It is coated with

The amount of triboelectric charge of microcapsule toner is USP43.
1 to 50 μcoul/g (preferably 3 to 30 μcoul/g) as measured by the two-component method described in No. 02201.
The amount of triboelectric charge of the toner using ul/g is 1μ
If a toner with a coul/g or less is used, the Coulomb force between the toner and the toner carrier is too small, which tends to cause so-called background staining in which the toner adheres to areas where no electrostatic latent image exists. On the other hand, the triboelectric charge amount of the toner is 50μ
If it exceeds coul/g, the Coulomb force between the toner and the toner carrier is too strong, and the amount of toner adhering to the electrostatic latent image area decreases, resulting in the phenomenon of so-called light image density.

The method for manufacturing the capsule toner of the present invention can utilize various known encapsulation techniques. For example, spray drying method, interfacial polymerization method, coacervation method, phase separation method, in-situ polymerization method, etc.
The methods described in Japanese Patent No. 38,991, Japanese Patent No. 3,326,848, Japanese Japanese Patent No. 3,502,582, etc. can be used.

As the soft material that can be used in the present invention, it is preferable to use a material that easily entangles with the fibers of plain paper under a linear pressure of about 20 kg/cm, and includes the following materials. Polyolefins such as polyethylene, polypropylene, and polytetrafluoroethylene; Styrenic resins such as ethylene-acrylic copolymers, polyethylene vinyl acetate, polyesters, polystyrene, styrene-butadiene copolymers, and polystyrene acrylics; Palmitic acid, stearic acid, and lauric Examples include higher fatty acids such as acids, polyvinylpyrrolidone, epoxy resins, phenol-terpene copolymers, polymethyl silicone, maleic acid-modified phenolic resins, methyl vinyl ether-maleic anhydride copolymers, and the like.

Examples of the hard material surrounding the soft solid core include polystyrene, poly-P-chlorostyrene, polyvinyltoluene, styrene-butadiene copolymer, styrene-acrylic acid copolymer, and styrene-maleic anhydride copolymer. Polymers or copolymers of styrene or its substituted products such as; polyester resins, acrylic resins, xylene resins, polyamide resins, ionomer resins, furan resins, ketone resins, terpene resins, phenol-modified terpene resins, rosin, rosin-modified penta erythritol ester,
Natural resin-modified phenolic resin, natural resin-modified maleic acid resin, coumaron indene resin, maleic acid-modified phenolic resin, alicyclic hydrocarbon resin, petroleum resin, cellulose phthalate acetate, methyl vinyl ether-maleic anhydride copolymer, starch Graft polymer, polyvinyl butyral,
Polyvinyl alcohol, polyvinylpyrrolidone, chlorinated paraffin, wax, fatty acids, etc. can be used alone or in combination.

Coloring agents used in the present invention include carbon black, nigrosine dye, lamp black, Sudan black SM,
First Yellow G, Benzidine Yellow, Pigment Yellow, India First Orange, Irgazine Red, Paranitroaniline Red, Toluidine Yellow
Red, Carmine FB, Permanent Bordeaux FRR
, Pigment Orange R, Lysol Red 2G, Lake Red C, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Prilliant Green B, Phthalocyanine Green, Oil Yellow GG, Zapon・
First Yellow CGG, Kayaset Y963, Kayaset YG, Sumiplast Yellow GG, Zapon First Orange RR, Oil Scarlet, Sumiplast Orange G, Orazole Brown B, Pomegranate First Scarlet CG, Eisenspiron Red BE
H, oil pink OP, etc.

(Implementation row 1) Styrene-
A microcapsule toner coated with a methyl methacrylate copolymer to a thickness of 0.3 μm was prepared.

To measure tripo, add 10 parts by weight of the toner and 250 to 4
USP 4302 is a mixture of 90 parts by weight of 00 mesh iron powder, placed in a ball mill pot, and stirred for 30 minutes.
When the amount of triboelectric charge of the toner described in the specification of No. 201 was measured, it was 28 μcoul/g.

An electrostatic latent image was formed using a known electrophotographic method, and developed using the apparatus shown in FIG. 1 using the microcapsule toner described above. The vibrating member 6 was vibrated at a frequency of approximately 50 Hz and an amplitude of 0.2 mm, and the non-magnetic sleeve 2 was vibrated at a circumferential speed of 120 mm/sec.
The sleeve was rotated to form a uniform toner coating layer with a thickness of about 50 μm on the sleeve.

The non-magnetic sleeve 2 and the electrostatic latent image carrier 1 are made to face each other with a gap of about 300μ maintained, and the non-magnetic sleeve 2 is
00 to several kilohertz, negative peak value -660 to -12
When development was carried out by applying a bias alternating current electric field of 00 V and a plus peak value of +400 to +800 V, a good developed image without rear fog was obtained.

(Comparative Example 1) Example 1. Example 1 except that a soft core material made of polyethylene and phthalocyanine blue was used as a toner instead of the microcapsule toner of Example 1. When development was carried out in the same manner as above, the resulting image had a low density and there were many areas where the toner was not developed even though there were electrostatic latent images.

(Example 2) A microcapsule toner was prepared in which a 5 to 10 μm soft core material made of 90 parts of polyethylene and 10 parts of pigment yellow was coated with a styrene-acrylonitrile copolymer to a thickness of 0.5 μm. .

To measure tripo, add 5 parts by weight of the toner and 250~ iron powder.
400 mesh and 95 parts by weight were mixed and stirred for 30 minutes in a ball mill pot, and the amount of triboelectric charge was measured and found to be 35 μcoul/g.

An electrostatic latent image was formed using a known electrophotographic method and developed using the above toner in combination with the apparatus shown in FIG.

The gap between the developing roller 111 and the electrostatic latent image holder 101 was maintained at 300 μm, and a single layer of toner having a thickness of about 80 μm was formed on the developing roller. As an AC waveform, add a DC component of 250V to the voltage peak value ±450V at a frequency of 200Hz,
When voltage peak values of +700V and -200V were applied, images with good gradation and no image fog were obtained.

(Comparative Example 2) In the same manner as in Example 2, except that instead of the microcapsule toner in Example 2, a 5 to 10 μm soft core material consisting of 90 parts by weight of polyethylene and 10 parts by weight of pigment yellow was used as a toner. After development, the image density was low, there were many areas where toner did not adhere despite the presence of electrostatic latent images, and background stains were also observed.

(Example 3) Particle size of soft core material consisting of 90 parts of polyethylene-vinyl acetate copolymer and 10 parts of toluidine red
A microcapsule toner was prepared by coating vinylidene chloride-acrylonitrile copolymer to a thickness of 0.2 μm around particles of 2 μm.

To measure tripo, add 10 parts by weight of the toner and 250 parts of iron powder.
~400 mesh was mixed, stirred in a ball mill pot for 30 minutes, and the amount of friction band joint charge was measured.
It was ul/g.

An electrostatic latent image was formed using a known electrophotographic method and developed using the above toner and the apparatus shown in FIG.

The gap between the developing roller 203 and the electrostatic latent image holder is 300 mm.
A toner layer of about 80μ was formed on the developer roller. As an AC waveform, a DC component of 250 V was added to a voltage peak value of ±450 V at a frequency of 200 Hz to give voltage peak values of +700 V and -200 V, and an image with good gradation without image fog was obtained.

(Comparative Example 3) Same method as in Example 3 except that instead of the microcapsule toner in Example 3, a soft material consisting of 90 parts of polyethylene-vinyl acetate copolymer and 10 parts of toluidine red was used as a toner. Where the development was done with
The skin was extremely dirty.

[Brief explanation of the drawing]

1 to 3 are cross-sectional side views of an example of an apparatus for carrying out the developing method according to the present invention. 1...Latent image carrier, 2...Toner carrier, 3...Toner, 4...
Hopper, 6... Vibration member, 7... Vibration generating means, 6a... Permanent magnet, 9... Cleaning blade, 10... Toner supply member, 11... Vibration transmission member made of flexible material, 101...
An electrostatic latent image holder including an optical semiconductor layer, 103...developing device,
107... One-component non-magnetic toner, 108... Magnetic roller,
109...Nonmagnetic sleeve, 110...Magnet, 111...Developing roller, 112...Magnetic brush, 113...Toner, 20
DESCRIPTION OF SYMBOLS 1...Latent image holding body, 203...Developing roller, 204...Applying roller, 206...Fiber brush, 207...Toner. Applicant Canon Inc. Agent Giichi Marushima

Claims (1)

[Claims] A latent image carrier that holds a latent image on its surface and a carrier that carries an insulating nonmagnetic toner are arranged with a certain gap in a developing section, and a soft material and a hard wall forming material that covers this are arranged. A microcapsule insulating non-magnetic toner consisting of microcapsules is applied to a toner carrier, the thickness of the applied layer is regulated to be thinner than the gap, and the absolute value of tripo when measured by the two-component method is A developing method in which toner of 1 to 50 μcoul/g is developed while being applied with an alternating electric field in a developing section.