JPS59187357A - Development method - Google Patents

Abstract

PURPOSE:To prevent changing of a triboelectrification amt. even if strong pressure is applied at the time of spreading a toner to maintain copy quality constant by incorporating a specified quaternary aminoalkyl ester in a hard material used for a microencapsulated toner. CONSTITUTION:A quaternary aminoalkyl (meth)acrylate is incorporated in the hard material of microcapsules composed of a soft material and the hard material for coating it. The obtained insulating nonmagnetic toner 3 is spread on a toner carrying roller 2 regulated in thickness thinner than the gap between a latent image bearing drum 1 and the roller 2, and carried to a developing section. An alternating electric field is applied there to the toner 3 to develop the latent image. A part of triboelectrified amt. disappears through a cationic amino resin present on the surface of the toner 3 by the addition of quaternary aminoalkyl (meth)acrylate to the hard material of the microencapsulated toner 3, even when strong force is applied and highly triboelectrified at the time of spreading the toner 3. As a result, rise of a triboelectrified amt. with time can be prevented, a constant charge is given to the toner, and image density is also kept constant.

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 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 then subjected to development.

An example of this developing method is shown in FIG. In the figure, during development, the toner supplied by a toner supply member 10 is vibrated by vibration members 6 and 7 and vibration generating means, 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, and development is completed. finish. After the development is completed, the toner remaining on the toner carrier is scraped off by the cleaning blade 9.

In addition, a rotatable magnetic roller that adsorbs a magnetic carrier to form a magnetic brush for charging component-based non-magnetic toner particles, 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 transferred to the surface of the electrostatic latent image 101 due to the electric field of the electrostatic latent image. Development ends.

The movable developer replenishing means transports and supplies the developer to the latent image holding member, the developer replenishing means, and the movable developer replenishing 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 described in 2. A movable coating means that moves in the same direction at a higher speed than the movable developer carrying means applies toner uniformly to the surface of the movable developer carrying means, and development is carried out by bringing this coated layer close to the electrostatic latent image area. There is a way.

An example of this developing method is shown in FIG. In the figure, development is performed by adsorbing the toner 207 to 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 bringing this brush close to the developing roller 203. By 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 one-component toner, these methods apply strong pressure when applying the toner to the toner carrier, which tends to increase the amount of triboelectric charge on the toner, and the friction increases with development time. This method has the drawback that the image density of the resulting copy changes over time as the amount of electrical charge increases, and 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, the hard material coats an insulating non-magnetic toner containing a quaternized aminoalkyl ester of acrylic acid or methacrylic acid on a support, and the coated layer has a thickness thinner than the gap. This is achieved by transporting the toner to a developing section in a controlled manner, and developing the toner while applying an alternating electric field to the toner in the developing section. That is, in a microcapsule toner consisting of a soft core material and a hard wall material, by including a quaternized product of aminoalkyl ester of acrylic acid or methacrylic acid in the hard wall material, when the toner is applied to the toner carrier, Even if the toner receives a strong force and acquires a high amount of triboelectric charge,
Since a part of the triboelectric charge obtained through the cationic amine resin present on the toner surface disappears, it is possible to prevent the triboelectric charge from increasing with development time, and the triboelectric charge is always constant. Image density is also kept constant because of the amount of toner provided.

The average particle size of the microcapsule toner that can be used in the present invention is 3 to 20 liters (preferably 5 to 10 liters). 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 the core to a thickness of 0.01 to 2 JL, preferably 0.1 to 0.3 JL.
It is coated with a thickness of g).

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., U.S. Patent Nos. 3 and 3
6. Acrylic acid that can be used in the present invention Alternatively, quaternized aminoalkyl esters of methacrylic acid include those represented by the general formula (R1+R2+R3 each represents a hydrogen atom or a lower alkyl group; m represents 1, 2, or 3; 6). Specifically, dimethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, and dimethylaminoethyl methacrylate.

Polymers obtained by polymerizing quaternized products such as dimethylamine propyl acrylate, diethylamine propyl acrylate, diethylamine propyl acrylate, and diethylamine propyl methacrylate-1.9 alone may be blended with other polymers, or may be blended with other types of monomers. Copolymerization may also be performed.

The ratio of blending or copolymerization with other resins is 0.1 to 90% (preferably 1 to 10%) with respect to other resins.

Examples of resins that can be copolymerized or blended with the quaternized aminoalkyl ester of acrylic acid or methacrylic acid include polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-butadiene copolymer, and styrene-acrylic acid. Copolymers, polymers or copolymers of styrene or its substituted products such as styrene-maleic anhydride copolymers: polyester resins, acrylic resins, xylene resins, polyamide resins, ionomer resins, furan resins, ketone resins, terpenes Resin, phenol-modified terpene resin, rosin, rosin-modified pentaerythritol ester, natural resin-modified phenol resin, natural resin-modified maleic acid resin, coumaron indene resin, maleic acid-modified phenolic resin, alicyclic hydrocarbon resin, petroleum resin, phthal Polymers or monomers such as cellulose acid acetate, methyl vinyl ether-maleic anhydride copolymers, starch graft polymers, polyvinyl butyral, polyvinyl alcohol, polyvinylpyrrolidone, chlorinated paraffins, waxes, fatty acids, etc. may 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, polyvinyl pyrrolidone, epoxy resins, phenol-terpene copolymers, polymethyl silicone, maleic acid-modified phenol resins, methyl vinyl ether-maleic anhydride copolymers, and the like.

Colorants used in the present invention include carbon black, nigrosine dye, lamp black, Sudan black SM,
First fist yellow 〇, benzidine yellow, hikment yellow, indo first orange, irgazine φ red, paranitroaniline fist ydo, h luidine
Red, Carmine FB, Permanent Bordeaux FRR
, Pigment Orange R, Lysol battle/Ndo 2G,
Lake Medium Red C, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant ψ Green B
, phthalocyanine green, oil yellow GG, 4f
Pon Φ First Yellow CGG, Kaya set Y8e
3. Kayaset YG, Sumiplast Orange 〇G, Zapon Fast Orange RR, Oil Φ Scarlet,
These include Sumiplast Orange G, Orazole Brown B, Pomelo First Scarlet CG, Eisenspiron Red-BEH, and Oil Pink OF.

(Example 1) 10 wt% of 2-talocyanine bullion in HoIJ ethylene
Around a uniformly dispersed soft material with an average particle size of 8 pL, 9525 of styrene and dimethylaminoethyl methacrylate whose amino group was quaternized with benzyl chloride was placed.
A microcapsule toner coated with a copolymer to a thickness of 0.3 g was prepared.

An electrostatic latent image was formed using a known electrophotographic method and developed using the toner described above 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 12 (1 mm/sec) to form a uniform toner coating layer with a thickness of about 50 JL on the sleeve. .

The non-magnetic sleeve 2 and the electrostatic latent image carrier 1 are separated by approximately 300 #
While maintaining a gap and facing each other, apply a frequency measurement of OO to several kilohertz to the non-magnetic sleeve 2, with a negative peak value of -660 to -1.
When development was carried out by applying a bias alternating current electric field of 200 V and a plus peak value of +400 to +eoov, a good developed image without rear fog was obtained. Also, the image density is
There was no change during continuous copying of 10,000 sheets.

When the triboelectric charge amount of the toner was measured by the method described in USP 4302201, it was 25 μc at the start.
/g, and after 10,000 sheets it was 27 p-c7g.

(Comparative Example 1) Styrene which is the wall of the microcapsule toner of Example 1
When development was carried out in the same manner as in Example 1 except that a 95=5 copolymer of styrene-dimethylaminoethyl methacrylate was used in place of dimethylallylamine, the image density decreased with the number of durable sheets in the continuous durability test. It happened.

The triboelectric charge amount of the toner is 1 full c/g at the start.

After 10,000 sheets, it was 36p, c/g.

(Example 2) 90 parts by weight of styrene-acrylonitrile copolymer and zintyl 7-minoethyl meccrylate were mixed with quaternary benzyl chloride around a 5-107 p soft material consisting of 90 parts of polyethylene and 10 parts of pigment yellow. A microcapsule toner was prepared in which the wall was coated with a mixture of 10 parts by weight of a polymer having a thickness of 0.5p.

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 was maintained at 300 g, and a single layer of about 80 g of toner 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.

Further, when 10,000 sheets were continuously copied, there was very little variation in image density. The amount of triboelectric charge is 15 at the start.
7zc/g, 10,000th sheet or 16pc/g.

(Comparative Example 2) Continuous copying of 10,000 sheets was carried out in the same manner as in Example 2, except that the polymer of the quaternary benzyl chloride of diethylaminoethyl tutacrylate of Example 2 was not added. However, the image density decreased as the number of copies increased.

The triboelectric charge amount was -1 full c/g at the start and -28 p, c/g after the 10,000th sheet.

(Example 3) Particle size of soft material consisting of 90 parts of polyethylene vinyl acetate copolymer and lo part of toluidine red 10-12
A microcapsule toner having a wall made of a mixture of 90 parts by weight of vinylidene chloride acrylonitrile copolymer and 10 parts by weight of a quaternized product of dimethylaminoethyl methacrylate with benzyl chloride was prepared around each particle.

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 #, and a single layer of about 80 g of toner was formed on the developing 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.

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

(Comparative Example 3) In the microcapsule toner of Example 3, 4 of benzyl chloride of dimethylaminoethyl methacrylate
When 10,000 copies were continuously made using the same method as in Example 3 for the non-vehicle material excluding graded materials, the image density decreased as the number of copies was made.

[Brief explanation of the drawing]

Figures 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----1 latent image carrier, 2---- toner carrier. 3----)ner, 4----hopper. 6-----Vibration member, 7-----Vibration generating means. 6a---1 permanent magnet, 9---cleaning blade. 10-----Toner supply member. 11--A vibration transmission member made of a flexible material. 101--An electrostatic latent image carrier comprising a photonic semiconductor layer. 103--'--Developing device, 107--Component non-magnetic toner 108--One magnetic roller, 109--
-1 non-magnetic sleeve 110---magnet,
111---One-view image roller. 112---One magnetic brush, 113---Toner. 201---one latent image holder, 203---one developing roller. 204---One application roller, 206---Fiber brush. 20? -----1-ner.

Claims (2)

[Claims] (1) A latent image carrier that holds a latent image on its surface and a toner carrier that carries an insulating nonmagnetic toner are arranged with a certain gap in the developing section, and a soft material and a hard wall that covers it are arranged. In the microcapsule made of a material, the hard wall material coats an insulating non-magnetic toner containing a quaternized aminoalkyl ester of acrylic acid or methacrylic acid on a toner carrier, and the coated layer is thinner than the gap. A developing method in which toner is transported to a developing section with a controlled thickness and developed while applying an alternating electric field to the toner. (2) The aminoalkyl ester of acrylic acid or methacrylic acid has the general formula (R+, R2, and R'3 are each a hydrogen atom or a lower alkyl group; m represents 1, 2, or 3). Developing method according to item 1.