JPS59185353A - Developing method - Google Patents

Abstract

PURPOSE:To obtain an image always constant in quality by preparing the outer shells of a microencapsulated toner with a hard material contg. (meth)acrylamide, and coating a toner carrying body with a layer of the obtained insulating nonmagnetic toner so as to control its thickness thinner than the gap between a photosensitive body and said toner carrying body. CONSTITUTION:A nonmagnetic insulating toner 113 is prepared by using as outer shells a homopolymer of amino(meth)acrylamide represented by the formula shown there (R4, R5, R6 are each H or alkyl and m is >2) or its quaternary ammonium salt, or a copolymer of one of said monomers and another monomer, or a mixture of said polymer and another polymer, and coating a soft material, such as polyolefin or polystyrene, with the obtained polymer or the like. A good image free from fog can be always obtained by forming a layer 107 of said toner 113 on a toner carrying body, such as a developing roller 111 in a thickness thinner than the gap between said roller 111 and a photosensitive roller 101, and applying an alternating electric field to said gap to form a toner image.

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 layer of toner on a developer (toner) carrier. It's about how to do it.

Conventionally, the following methods are known as developing methods using -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 used. When the developer under the developer carrier is pumped up to the developer carrier 2, the developer in the pumped-up portion is activated by vibration, and a developer layer of a predetermined thickness is formed 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, during development, the toner supplied by the toner supply member 10 is vibrated by the vibration member 6.7 and the vibration generating means, collides with the toner carrier 2, and is frictionally charged between the toner carrier 2 and the toner carrier 2. When the toner is carried on the toner carrier 2 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, and development is completed. finish. After the development is completed, the I/toner remaining on the toner carrier 1- is scraped off by the cleaning blade 9.

In addition, a rotatable magnetic roller that adsorbs a magnetic carrier for charging component-based non-magnetic toner particles to form a magnetic brush, and a rotatable magnetic roller that transfers the toner particles of the roller to form an electrostatic image carrier. It has a developing roller for developing the electrostatic 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 of developing an electrostatic image.

An example of this developing method is shown in FIG. In the figure, development is carried out by carrier particles of a magnetic brush 112 or toner 113.
Frictional charging causes toner to adhere to the carrier surface using Coulomb force. A” The toner is placed on the developing roller 11.
1, the toner uniformly adheres 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 transferred to the surface of the electrostatic latent image 101 due to the electric field of the electrostatic latent image. The development is completed.

Further, the movable developer supporting means carries and conveys the developer and supplies it to the latent image holding member, the developer replenishing means, and the movable developer supporting means receives the developer from the developer replenishing means. a movable application means for applying a developer to the surface of the movable developer support means, the movable application means having a fiber brush carrying the developer on the surface thereof, and contacting the movable developer support means at this abutting portion; A movable coating means that moves at a higher speed than the movable developer carrying means in the same direction as the movable developer carrying means uniformly coats the toner on the surface of the movable developer carrying means, and develops by bringing this coated layer close to the electrostatic latent image area. There is a way to do it.

An example of this developing method is shown in FIG. In the figure, development is performed by adsorbing the toner 207 onto the surface of the fiber brush 206 by 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 bringing them close together and applying an electric field between the coating roller 204 and the developing roller 203, the toner is uniformly transferred from the surface of the fiber brush 206 to the surface of the developing roller 203. Thereafter, the toner on the surface of the developing roller 203 is transferred to the surface of the electrostatic latent image by an electric field formed by the electrostatic latent image on the surface of the electrophotographic photoreceptor 201, thereby completing the development.

Compared to conventional developing methods using single-component toners, these methods tend to increase the amount of triboelectric charge on the toner due to the strong pressure applied when applying the toner to the toner carrier, and the development time increases. At the same time, the amount of triboelectric charge increases by 1, and the image density of the resulting copy changes with time, resulting in a drawback that the quality of the copy cannot be kept constant.

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

Another object of the present invention is to provide a developing method in which the triboelectric charge amount of toner does not increase with development time.

An object of the present invention is to arrange a latent image holding member that holds a latent image on its surface and a supporting member that carries an insulating non-magnetic toner with a certain gap between them in a developing section. In the microcapsule made of a material, an insulating non-magnetic toner in which the hard material contains acrylamide of acrylic acid or methacrylic acid is applied to a carrier, and the applied layer is regulated to a thickness thinner than the gap and developed. This is achieved by conveying the toner to a developing section and developing it while applying an alternating electric field to the toner in a developing section.

That is, in a microcapsule toner consisting of a soft core material and a hard wall material, by containing acrylamide of acrylic acid or methacrylic acid in the hard wall material, when the toner is applied to the toner support material, the toner is subjected to strong force. Even if a high amount of triboelectric charge is obtained, part of the amount of triboelectric charge obtained through the cationic amine resin present on the toner surface disappears, so the amount of triboelectric charge increases with development time. Since a constant amount of triboelectric charge is always applied to the toner, the image density can also be kept constant.

The average particle size of the microcapsule toner that can be used in the present invention is 3 to 20 pL (preferably 5 to 10 pL).
). The toner contains 1 to 30 iit% of coloring dyes and pigments (
A soft solid core containing preferably 5 to 15 wt%) is surrounded by a hard material. O1-2 (preferably 0.1-0.3
pL).

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, 1n-situ polymerization method, etc.
Methods such as those described in Specification No. 38,991, Specification No. 3.32 [(, Specification No. 848, Specification No. 3,502,582, etc.) can be used.

Acrylic acid or methacrylic acid acrylamides that can be used in the present invention include aminoalkylamides of acrylic acid or methacrylic acid represented by the general formula (R4, R5, and R6 are R9 or alkyl groups, respectively) and quaternary ammonium salts thereof. is applicable. Specifically, dimethylamine ethyl acrylamide, dimethylaminoethyl methacrylamide, diethylaminoethyl acrylamide, diethylamine ethyl methacrylamide, dimethylamine propylacrylamide, dimethylamine propyl methacrylamide.

Examples include diethylaminopropyl acrylamide and diethylaminopropyl methacrylamide.

These acrylamides of acrylic acid or methacrylic acid may be polymerized alone and blended with other polymers, or may be copolymerized with other types of monomers. The ratio of blending or copolymerization with other resins is 0.1 to 80% (preferably 1 to 10%) relative to other resins.

Examples of resins that can be copolymerized or blended with acrylamide of acrylic acid or methacrylic acid include polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-butadiene copolymer, styrene-acrylic acid copolymer, and styrene-anhydride. Polymers or copolymers of styrene or its substituted products such as maleic acid copolymers; polyester resins, acrylic resins, xylene resins, polyamide resins, ionomer resins, furan resins, ketone resins,
Terpene resin, phenol-modified terpene resin, rosin,
Rosin-modified pentaerythritol 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 Polymers or monomers such as acid copolymers, dust-resistant graph I polymers, polyvinyl butyral, polyvinyl alcohol, polyvinylpyrrolidone, chlorinated halaffins, waxes, fatty acids, etc. can be used.

Examples of soft materials that can be used in the present invention include the following. 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.

Coloring agents used in the present invention include carbon black, nigrosine dye, lamp black, sutan black SM,
First Yellow G, Benzidine Yellow, Pigment Yellow, India First Orange, Irgazine Red, Paranitroaniline Red, Toluidine Red, Carmine FB, Permanent Pol;' -
F RR, Pigment Triorange R, Resole Red 2G, Lake Number 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, Kaya Set Y9f (
3. Kayaset YG, Sumiplast Orange GG, Zapon Fast Orange RR, Oil Scarlet, Sumiplast Orange G, Orazole Medium Brown B, Pomelo First Scarlet CG, Eisenspirone Red @BEH, Oil Pink OP, etc.

(Example 1) A 95:5 mixture of styrene-dimethylaminoethylmethacrylamide was placed around a soft core material having an average particle size of 8 grains in which phthalocyanine blue was uniformly dispersed at 1% by weight in polyethylene.
A microcapsule toner coated with a copolymer to a thickness of 0.3 g was prepared.

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

The non-magnetic sleeve 2 and the electrostatic latent image carrier 1 are approximately 300 #
Keeping a gap and facing each other, apply a frequency of 100 to several kilometers H2 to non-magnetic sleeve 2, and a negative peak value of -6.
60~-+200V and plus peak value +400~+8
When development was carried out by applying a bias alternating current electric field of 00 V, a good developed image without rear fog was obtained. Further, the image density did not change during continuous copying of 10,000 sheets.

When the triboelectric charge amount of the toner was measured using the method described in USP 4302201, it was 21 gc at the start.
/g, and after 10,000 sheets it was 23p, c/g.

(Comparative Example 1) Styrene which is the wall of the microcapsule toner of Example 1
Development was carried out in the same manner as in Example 1, except that a 95:5 copolymer of styrene and dimethylaminoethyl methacrylate was used instead of dimethylaminoethylmethacrylamide 2, and the image density remained stable in the continuous durability test. It decreased with the number of sheets.

The triboelectric charge amount of the toner is 18 g c/g at the start.
.

After 10,000 sheets, the temperature was 36 c/g.

(Example 2) 90 parts by weight of a styrene-acrylonitrile copolymer and 10 parts by weight of a polymer of dimethylaminoethyl methacrylamide were placed around a 5-10 part soft core material consisting of 90 parts of polyethylene and 10 parts of pigment yellow. A microcapsule toner was prepared in which the walls were coated with a mixture of 0.5 mm and 0.5 mm thick.

The toner was developed in combination with the apparatus of FIG.

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

Further, when 10,000 sheets were continuously copied, there was very little variation in image density. The amount of triboelectric charge is 11 at the start.
9 river c/g, the 10,000th sheet was 123 c/g (Comparative Example 2) Same as Example 2 except that the dimethylamine ethyl methacrylamide polymer of Example 2 was not added. Although 10,000 sheets were continuously copied, the image density decreased as the number of copies increased.

The triboelectric charge amount was 117 pLc/g at the start and -28 pLc/g after the 10,000th sheet.

(Example 3) Particle size of soft core material consisting of 90 parts of polyethylene vinyl acetate copolymer and 10 parts of toluidine red 10-12
I1. A microcapsule toner was prepared having a wall around the particles made of a mixture of 90 parts by weight of vinylidene chloride acrylonitrile copolymer and 10 parts by weight of diethylaminoethylmethacrylamide polymer.

Development was carried out using the toner and the apparatus shown in FIG. The gap between the developing roller 203 and the electrostatic latent image holder 201 was maintained at 300 mm, and a single layer of toner of about 80 pL was formed on the developing roller. When an AC waveform with a frequency of 200 Hz and a DC component of 250 V was added to a voltage peak value of ±450 V to give voltage peak values of +700 V and -200 V, an image with good gradation without image fogging was obtained.

Further, even after running for 10,000 sheets, the variation in image density was very small.

(Comparative Example 3) Using the microcapsule toner of Example 3, continuous copying of 10,000 sheets was performed in the same manner as in Example 3 except that diethylamine ethyl methacrylamide was omitted, and the image density decreased with the number of copies. Oops.

[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. 5 1---1 latent image carrier, 2---) toner carrier. 3-1-1-ner, 4----Hopper. 6-----Vibration member, 7-----Vibration generating means. 6a---1 permanent magnet, 9---11 cleaning blade 10---toner supply member. 11--A vibration transmission member made of a flexible material. +01---An electrostatic latent image carrier including a photonic semiconductor layer. I
ll --- one developing roller. 112---1 magnetic brush, 113---1 toner. 201--1 latent image holder, 203-1--developing roller. 204---One application roller, 20B---One fiber brush. 20? ---One toner. Applicant Canon Co., Ltd. 6 bo o tycL 6c zuO8

Claims (2)

[Claims] (1) 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 constant gap in the developing section, and a soft material and a hard wall material that covers this are arranged. In the microcapsule, the hard wall material coats an insulating non-magnetic toner containing acrylamide of acrylic acid or methacrylic acid on a toner carrier, regulates the thickness of the coated layer to be thinner than the gap, and develops it. A developing method in which an alternating electric field is applied to the I-ner in the developing section. (2) A patent claim in which the acrylamide of acrylic acid or methacrylic acid is an aminoalkylamide of acrylic acid or methacrylic acid represented by the general formula (R4, R5, R6 are each R2 or an alkyl group) and a quaternary ammonium salt thereof The developing method according to item 1.