JPS6079363A - Developer for electrostatic charge image - Google Patents

Abstract

PURPOSE:To prevent the sticking of a toner to the surface of a photosensitive body by mixing the toner particles contg. a resin causing plastic deformation under a prescribed pressure, colorants and polyvinylidene fluoride with polyvinylidene fluoride powder. CONSTITUTION:When a fixing system applied is a pressure fixing system, a pressure sensitive resin or a resin mixture having >40 deg.C glass transition point is used as a resin for fixing. The amount of the resin for fixing contained in a toner is >=35wt% of the total amount of the toner, and the amount of a pigment for color control and a dye is <10wt% of the total amount of the toner. The toner is composed of the resin, the colorants and polyvinylidene fluoride. Magnetic powder may be added to the toner to obtain a magnetic toner. The amount of the ferromagnetic body contained in the toner is 35-75wt% of the total amount of the toner. To the toner particles is added 0.02-5wt% polyvinylidene fluoride powder basing on the total amount of the toner particles, and they are mixed. The sticking of the resulting toner to a photosensitive body and the damage of the photosensitive body can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic image developer used for developing an electrostatic image formed on the surface of an image carrier by a magnetic brush method.

An electrostatic charge image is formed on the surface of an image carrier such as magnetized cadmium coated with zinc oxide, selenium, an organic photoconductor, or mytsu (trade name), and this electrostatic charge image is developed with a magnetic brush υ. Electrophotographic reproduction methods in which a toner image is transferred onto a transfer sheet 1 and then fused to obtain the final image are well known.

In the magnetic brush method described above, the developer is often mixed with a magnetic carrier such as iron powder, steel balls, or ferrite particles, and non-magnetic toner, which is insulating particles in which a colorant is dispersed in a resin. used (for example, Special Publication No. 53-150)
No. 40, JP-A-50-56946, JP-A No. 54-1346
No. 36.

(Refer to publications such as No. 56-11459 and No. 56-11460). In the magnetic brush development method using this two-component developer, carrier and toner are mixed and stirred at a predetermined ratio, both are charged, the toner is charged to a predetermined polarity, and only the toner is imprinted onto the surface of the image carrier. It has the advantage of being easy to transfer because it uses an insulating toner.

Other known magnetic developers include one-component magnetic toners whose main components are resin and magnetic powder (for example,
(See Japanese Patent Laid-Open Nos. 11149-4532, 50-50042, and 57-975/I).

However, these magnetic developers are the so-called P P
When using the C method, there is a problem that the toner particles land on the surface of the photoreceptor, or the surface of the photoreceptor is damaged by the toner particles. For example, in a two-component developer, , the toner particles have a fine particle size (5 to 3
0 μm), and relatively low melting point (90~
Since a thermoplastic resin (110° C.) is used, it easily adheres to the surface of the photoreceptor. Furthermore, if the toner remaining on the surface of the photoreceptor after transfer is cleaned using a mechanical means such as a blade, the toner is easily crushed and pushed onto the surface of the photoreceptor.
One of them gets hurt. Alternatively, in the case of magnetic toner, there is a problem that the magnetic powder is exposed on the surface of the toner particles, and the surface of the photoreceptor is scratched (see, for example, Japanese Patent Publication No. 5G-46596@Teru).

In particular, in the case of toner for pressure fixing, a material that can be plastically deformed under low pressure is used as a resin component (see, for example, Japanese Patent Publication No. 54-3347), so the 1-toner is easily crushed and the photoreceptor is There is a strong tendency to arrive at (=J).

The object of the present invention is to provide an electrostatic image developer capable of pressure fixing that effectively prevents adhesion to and damage to the surface of a photoreceptor.

The structure of the present invention includes toner particles containing a resin that can be plastically deformed under a predetermined pressure, a colorant, and polyvinylidene fluoride.
It is a developer for electrostatic images mixed with polyvinylidene fluoride powder.

Ordinary toner particles contain a resin and a colorant as necessary components, but as a result of study by the present inventor, polyvinylidene fluoride is contained inside the toner particles, and the toner particles are made of polyvinylidene fluoride. It has been discovered that adhesion of toner particles to the photoreceptor and damage to the photoreceptor can be effectively prevented by mixing with powder. This polyvinylidene fluoride is a type of fluororesin (CF2 = C
l-12) It has excellent mold releasability and is resistant to heat (
melting point 160-180°C, heat distortion temperature 90°C, thermal decomposition temperature 380°C), and excellent mechanical properties (tensile strength 390-520 kO/cm', bending rigidity 1.4-1
．． 8x10' kmcm2), it is thought that such an effect can be exhibited.

The blending amount of polyvinylidene fluoride is in the range of 0.02 to 5% based on the total amount of toner particles. This is 0.
02tl! If the amount is less than 5%, there is no effect, and if it exceeds 5%, the fixing performance will be impaired. In addition, more preferably, the blending amount of polyvinylidene fluoride is 0.1 to
It is in the range of 2% by weight. A specific example of polyvinylidene fluoride is Penu Soruto Co., Ltd. 11461,460,45
0,310 etc. are mentioned.

When the fixing method is a pressure fixing method, for example, the following pressure-sensitive resins are used. Higher fatty acids, higher fatty acid total salts, higher fatty acid derivatives.

Higher fatty acid amides, waxes, rosin derivatives.

Algide resin, epoxy modified phenolic resin.

Natural resin modified phenolic resin, amino resin, silicone resin, polyurethane, urea resin, polyester resin, acrylic acid or methacrylic acid and long chain algyl methacrylate-1, copolymerized oligomer with long chain alkyl acrylate, styrene and long chain Copolymerized oligomers such as alkyl acrylates and long-chain alkyl methacrylates, polyolefins, ethylene-vinyl acetate copolymers, ethylene-vinyl acetate copolymers, maleic anhydride copolymers 2 petroleum residues, rubbers, etc. .

These resins can be arbitrarily selected and mixed as desired, but in order not to reduce the fluidity when used as a toner, resins with a glass transition point exceeding 40°C or resin mixtures are effective. used. The content of the fixing resin in the toner is the proportion excluding ferromagnetic fine particles, color adjustment pigments, dyes, and charge control agents, but in order not to reduce the fixing properties of the toner, it is It is necessary to add more than % by weight.

As the color-adjusting pigment and dye, any of the various pigments used in general dry developers can be used. However, it is necessary to add the toner to the total amount of the toner within a range that does not deteriorate the electrical properties of the toner. In the present invention, the amount of these additions is 10% to the total width of the toner.
Less than % by weight is suitable. Pigments and dyes that can be used include, for example, nigrosine dye, aniline blue, calco oil blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, Malachi I-green oxalate, lamp black 1. Rose Bengal and mixtures thereof are used. If the ferromagnetic fine particles themselves are colored and there is no need to add these color modifiers, there is no need to add them to the toner.

In addition, when carbon black is used, carbon black is a conductive particle and does not reduce the electrical insulation properties of the toner. It is necessary to add it within.

The above-mentioned pigments and dyes 11 are used in combination with ferromagnetic fine particles and fixing resin to control frictional charging between the sleeve surface of the magnetic roll for toner development and the surface of the recording medium. can be selected and used. but,
In order to control the electric charge of the toner, a conventionally known dye or pigment can be added as a charge control agent. Examples include nigrosine dyes that have positive triboelectric charging properties, nigrosine dyes modified with higher fatty acids, and metal-containing (Cr) azo dyes that have negative triboelectric charging properties.

The toner according to the present invention is composed of a resin 9 colorant and polyvinylidene fluoride, and may be mixed with a magnetic carrier to form a two-component developer, or may be a one-component developer by containing magnetic powder in 1-Q particles. It can also be a magnetic toner.

In this case, the magnetic powder is a substance that is extremely strongly magnetized in the direction of a magnetic field, such as an alloy containing a ferromagnetic element such as iron, cobalt, 'XXfluor, etc., including ferrite and magnetite, or Compounds, various alloys exhibiting ferromagnetism, etc. can also be effectively used when subjected to some kind of treatment such as heat treatment.

Since these ferromagnetic substances are contained in the toner, it is desirable that the average particle size is about 0.1 to 3 μl, and the amount contained in the toner is 35 to 3 μl based on the total weight of the toner.
The content is preferably 75% by weight. 1 if less than 35% by weight
- The magnetic force of the toner decreases, and the toner is removed from the sleeve.
]+2, the image becomes distorted, and the fluidity of the toner also decreases. If it exceeds 75% by weight, the ankle properties will deteriorate.

The developer according to the present invention can be prepared by a known manufacturing method, such as a pulverization method or a fog drying method, using each of the above-mentioned compositions.

Next, examples of the present invention will be described.

Example 1 Wax (Mitsui Petrochemical +11 WAX200P) 24
Parts by weight, 16 parts by weight of ethylene-vinyl acetate copolymer (AC1, manufactured by Mitsui Polychemicals) 400, 59 parts by weight of FeaO+ (EPT500, manufactured by Toda Kogyo), and 1 part by weight of polyvinylidene fluoride (461, manufactured by Pennwalt) were dry mixed. After wet kneading at 160'C in a heating kneader, the mixture was cooled and solidified, and the cooled and solidified product was coarsely ground in a ball mill, and then finely ground in a jet mill (fJ) to obtain particles with an average particle size of 20 μm. After classifying the particles, they were mixed with polyvinylidene fluoride to obtain a magnetic toner with a particle size of 5 to 25 μm and a resistance of 5×10”Ω・Cl1.The obtained magnetic toner was 51i A copy test was conducted on the Se drum, but no obvious scratches or toner adhesion were found on the Se drum.

Comparative Example 1 A magnetic toner was prepared in the same manner as in Example 1 except that polyvinylidene fluoride was not added, and when copies were made, scratches on the photoreceptor were observed on approximately 10,000 sheets, but only one portion In this case, toner stickiness was more strongly observed.

Example 2 Polyvinylidene fluoride (Penwall 1 to 450 manufactured by Co., Ltd.) 2
Heavy FFI part, Boris Diren (Sanyo Chemical Haima ST 1
20) 15fJiiiu part, 7mito')x([J
Example 1: Bisamide manufactured by Honkasei Co., Ltd.) 18 layered portions were mixed with e304 (EPT500 manufactured by Toda Kogyo Co., Ltd.) 63 layered portions, and polyvinylidene fluoride was mixed with the toner after classification.
A developer was prepared in a similar manner.

Thereafter, a copy test of 50,000 sheets was performed using a copying machine using an Se drum, and it was confirmed that the surface of the SO drum was good.

Comparative Example 2 A developer with the same composition as above but excluding polyvinylidene fluoride was made and subjected to a bee test. After 4,000 sheets, strong toner adhesion was observed on the photoreceptor, and black spots appeared on the white part of the image. Natsu (appeared.

Example 3 Polyvinylidene fluoride (450 manufactured by Pennwalt Co., Ltd.) triple fli portion was first added to 4-methyl-1-benzone.1-polymer (Example 1 of Patent Application No. 57-225434) 7
7 parts by weight, 10 parts by weight of low molecular weight polypropylene (Viscol 550P made by Sanyo Kasei), 10 parts by weight of carbon black (#30 made by Mitsubishi Kasei), and after classifying polyvinylidene fluoride (same as above). A toner was prepared in the same manner as in Example 1. This one
-No 5-layer M part with iron powder carrier (EFV20 made by Nippon Iron Powder)
0/300) Adjust the developer by mixing with 95 overlapping color part,
When the transferred image was pressure-fixed using a commercially available copying machine (Mita!1i81Dc131) at a linear pressure of 20 ko/cm and image evaluation was performed, good results similar to those of Example 1 were obtained.

Comparative Example 3 A developer was prepared under the same conditions as in Example 3, except that polyvinylidene fluoride was not added, and an image 51' rating was performed. As in Comparative Example 1, satisfactory IJ results were not obtained. .

As described above, the present invention has the following advantages: By mixing polyvinylidene fluoride powder with toner particles containing polyvinylidene fluoride and a resin that can be plastically deformed under a predetermined pressure,
This invention can be expected to provide a developer for electrostatic images that can effectively prevent J adhesion and damage to the surface of a photoreceptor, and can be said to be an invention with excellent practical effects.

patent applicant Hitachi Metals Co., Ltd.

Claims (2)

[Claims] (1) A developer for electrostatic images, characterized in that polyvinylidene fluoride powder is mixed with toner particles containing a resin that can be plastically deformed under a certain pressure, a colorant, and polyvinylidene fluoride. (2) The developer for electrostatic images according to claim 1, which contains magnetic powder as at least a part of the colorant.