JPS60247648A - Electrostatic charge developing carrier - Google Patents

Abstract

PURPOSE:To obtain a carrier superior in acceptance potential and adhesion between a core and a coating material by coating a core with the coating material of a specified compd. CONSTITUTION:The surface of the core is coated with a compd. or a condensate of said compd. represented by the formula in which (n) is an integer of 0-3; R is an optionally substd. hydrocarbon group, e.g., a lower alkyl, such as methyl, ethyl, n-butyl, or t-amyl; and X is a univalent or multivalent carboxylic acid residue having a perfluoroalkyl group in the molecule, and said group is directly or indirectly combined with this carboxylic group. As the core, 20-500mum diameter particles, such as those of Fe3O4, MnZn ferrite, Cr2O3, iron, nickel, or glass beads, are exemplified. An amt. of coating material to be used is 0.001-5wt%, preferably, 0.01-2.5wt% of the core.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to developers, particularly carrier particles, for developing electrostatic latent images in electrophotographic, electrostatic and recording processes.

Conventional technology The electrophotographic method or electrostatic recording method uses a magnetic brush method to form an electrostatic latent image on a photoreceptor or electrostatic recording material, and then transfers this toner image to a transfer material such as paper to obtain a copy. .

During this development, a carrier is used to impart a predetermined charge to the toner.

Carriers are generally classified into coated carriers and non-coated carriers, and coated carriers are mainly used from the viewpoint of controlling chargeability and preventing toner adhesion.

There are various properties required of this coat carrier, and particularly important properties include triboelectric charging properties, impact resistance, abrasion resistance, adhesion between the core material and the coating material, and uniformity of charge distribution. Conventional fluorinated vinyl type.

Polymers or acrylic polymers are used as carrier coating materials, but although fluorinated vinyl polymers have excellent charging properties, they have poor adhesion to the core, and acrylic polymers have poor mechanical strength and adhesion to the frame. Although it has excellent properties, it has disadvantages such as poor charging property, mixed toner with different polarity charge, and slow charging speed. Also, Go-h#I) L+ number go, cornerstone 11th π
The reproduction of the vertical and halftone areas and halftone areas was poor.

OBJECTS OF THE INVENTION The present invention was made in view of the above circumstances, and it is an object of the present invention to improve the conventional drawbacks and provide a carrier that has excellent charging properties and excellent adhesion between the core and the coating material. The purpose is also to provide a carrier that is easy to reproduce solid halftones.

Structure of the Invention The object of the present invention is to transform the surface of the core material into a material with the general formula % (%) [wherein R is an integer from O to 3, R is a hydrocarbon group or a substituted hydrocarbon group, and X is a perfluoro group in the molecule. The carboxylic acid residues having . ] or a condensate thereof.

The coating material used in the present invention is a compound represented by the above-mentioned general formula or a condensate thereof; for example, R is methyl, ethyl, -propyl, leupropyl, roupropyl,
selected from lower alkyl such as i-methyl, 7-mil, i-amyl, t-amyl, etc. X is a monovalent or polyhydric carboxylic acid containing a perfluoroalkyl group in the molecule; Compounds directly bonded to a carboxyl group and compounds in which a non-fluoroalkyl group is bonded to a carboxyl group via another group; examples of X include OF 0OOH, 02F5C
,OOH,03F7COOH,C,F,C0OH.

05F,,C0OH,06F,,C0OH,07F□5
0O0H, 08F□7COOH.

C3F1. Co0H1C1oF21COOH1C1□F
23C00H1018F37CoOHSC, F5QC6
I(4COOH,3,5-(C,F2O)2C,H3C
OOH13,4,5-(C,F2O)3C6H2COO
H, 06F□10C6H4COOH.

C, Ei'□70C6H4C00H109F□90C6
Examples include H4COOH, among which those in which the alkyl S portion of the non-fluoroalkyl group is an alkyl having 3 or more carbon atoms are preferably used because of their large ability to lower surface tension.

As the core material used in the present invention, various known materials can be used, such as triiron tetroxide, iron sesquioxide, Mn
Zn ferrite, IqiZn7 erite.

Bα ferrite, chromium dioxide, iron, nickel.

Particles having a particle size of about 20 to 500 micrometers, such as cobalt and glass peas, are exemplified.

Further, particles in which magnetic powder is dispersed in a binder resin may be used as the core material.

The carrier particles of the present invention can be obtained by surface-treating the core material described above with a coating material represented by the general formula described above, and forming a coating layer of the coating material on the surface of the core material by chemical bonding or adsorption. can. For surface treatment of the core material, for example, the core material is immersed in a solution in which the coating material is dissolved, followed by desolvation, drying, and high temperature treatment, or the core material is suspended in a fluidized bed and the coating material is treated. A method of spraying a solution, drying it, and further treating it at high temperature can be used. These methods do not necessarily require high temperature treatment, but from the viewpoint of improving adhesion,
It is better to process it with

The coating amount of this coating material is 0 per 100 parts by weight of the core material.
．． The amount is preferably about 0.01 to 5 parts by weight, preferably about 0.01 to 2.5 parts by weight.

The carrier according to the present invention is used in combination with a toner. Various known toners can be used, and the toner may be used in amounts ranging from 1 to 20 parts by weight per 100 parts by weight.

This developer consisting of carrier and toner is used to develop the electrostatic latent image formed on the photoreceptor or electrostatic recording medium, and various developing methods such as magnetic brush development method and cascade R development method are applied. can.

Effects of the Invention The carrier of the present invention has various excellent effects by coating the core material with a coating material of a specific compound. First, compared to conventional coated carriers, it has superior charging properties and uniformity of charge distribution, that is, the charging speed is significantly faster.
There is no attenuation or accumulation of charge, and these are stable even under changes in temperature and humidity or long-term use, and the charge distribution is sharp and does not contain charges of different polarity. Furthermore, the adhesion between the core material and the coating material is excellent, and the coating material will not peel off. Another noteworthy point is that the coating material according to the present invention has a relatively low resistance, and does not cause the deterioration in image quality in solid areas and halftone areas that is observed in conventional coat carriers.

Example The present invention will be explained in more detail with reference to Examples below.

Synthesis Example Zr (QC, Ho), 76.6 parts (0.2 fish l) was dissolved in 100 parts of Par70 tb-hexane and heated at 10°C.
Cooled below. Par 70 rolls on this - 10 hexane
93.6 parts of 08F□7COOH dissolved in 0 parts (0.2 parts
The mixture was cooled to 215° C. or lower and added dropwise over 20 minutes while stirring. After the entire amount was added dropwise, the mixture was stirred at room temperature for 30 minutes. Thereafter, the mixture was heated to 60° C. and the reaction was continued for 30 minutes, and the solvent and the produced rhubutanol were removed under reduced pressure. 10wH
& .

After substantially removing volatile matter at 60°C, 7200 parts of perfluoro-hexane was added and dissolved to form a pale yellow transparent solution 3.
55.4 parts were obtained.

This product is (C4H80)3Zr(08F□70oO
), and 100 parts by weight of Mn-Zn ferrite particles with an average particle diameter of 100 μm and a resistance of 109 Ω were added as a core material to 100 parts by weight of the solution obtained in the synthesis example and 1 part of Nomo 70 roll-hexane.
A coating layer was formed by a fluidized bed coating method using a coating solution containing 0 parts by weight to obtain a carrier. This coated carrier had a resistance of approximately 1010 ohms.

To 100 parts by weight of this carrier, 3 parts by weight of a toner having an average particle diameter of 12 μm, consisting of 92% Styrene'n-BMA copolymer and 8% carbon black, was mixed to prepare a developer.

When this developer was stirred in a blender and its charging properties were examined, the saturation charging speed was very fast at 1 minute, and it did not contain charges of different polarity. On the other hand, the conventional carrier coated with methyl methacrylate resin had a saturation charging speed of 10 minutes and had different polar charges.

When copies were made using this developer, copies with excellent solid and halftone reproduction and few capris were obtained.

There is no change in image quality even after 50,000 copies, and the amount of charge is 14 μC.
/II.

When I observed the surface of the carrier, I found that the coating material had peeled off (and 3 other people).

Claims (1)

[Scope of Claims] A core material and the following general formula % on it [In the formula, R is an integer from θ to 3, R is a hydrocarbon group or a substituted hydrocarbon group, and X is a nosafe fluoro group in the molecule. The carboxylic acid residues having . ] A carrier for electrostatic charge development, characterized in that it has a coating layer of a compound represented by the following formula or a condensate thereof.