EP0405503A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Carrier for developer

Assignee: Kyocera Mita Industrial Co Ltd

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Filing: 1990-06-27

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Granted: —

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Expires: 2010-06-27

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Abstract

Abstract A resin-coated magnetic carrier for two-component developers which comprises magnetic particles and a resin coating formed on the individual magnetic particles is described. The resin coating is made of a cured resin composition comprised of an alkylated melamine resin whose molecular weight satisfies the following inequality M ≧ 1100C - 400 wherein M represents a weight average molecular weight of the resin and C represents the number of carbon atoms in the alkyl moiety, and an acryl-modified silicone resin. The use of the composition is effective in preventing the coated particles from melt adhesion and in forming a smooth and uniform coating layer on individual particles. The resin-coated carrier is significantly reduced in amount of spend carrier and has good durability, moisture resistance, chargeability.

Inventors

👤 Hideaki Kawata
👤 Masatomi Funato
👤 Nobuaki Mita Industrial Co. Ltd. Kawano
👤 Koji Honda

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-11-07 21:40

CPC Classifications

G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/113; G03G9/1132; G03G9/1137; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/105; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993; Y10T428/2995

Claims Analysis

Total Claims: 9

Claim 1

Independent Claim 82 words

A resin-coated magnetic carrier for two-component developer which comprises magnetic particles and a resin coating formed on the surface of individual magnetic particles, the resin coating being made of a cured resin composition which comprises an alkylated melamine resin having a molecular weight satisfying the following inequality (1) M ≧ 1100C - 400 (1): wherein M represents a weight average molecular weight of the resin and C represents the number of carbon atoms in the alkyl moiety, and an acryl-modified silicone resin.

Claim 2

Dependent Claim 82 words

Claim 3

Dependent Claim 19 words

A resin-coated magnetic carrier according to Claim 1, wherein the alkyl moiety has from 1 to 4 carbon atoms.

Claim 4

Dependent Claim 26 words

A resin-coated magnetic carrier according to Claim 1, wherein a degree of alkylation in the alkylated melamine is in the range of from 10 to 85%.

Claim 5

Dependent Claim 31 words

A resin-coated magnetic carrier according to Claim 1, wherein a ratio by weight of the alkylated melamine resin and the acryl-modified silicone resin is in the range of 1:99 to 30:70.

Claim 6

Dependent Claim 34 words

A resin-coated magnetic carrier according to Claim 1, wherein the acryl-modified silicone resin is a reaction product between an acrylic resin and a silicone resin at a ratio by weight of 80:20 to 20:80.

Claim 7

Dependent Claim 32 words

A resin-coated magnetic carrier according to Claim 5, wherein the acryl-modified silicone resin has a group reactive with methylol group at a concentration of from 1 to 400 mmols/g of the resin.

Claim 8

Dependent Claim 23 words

A resin-coated magnetic carrier according to Claim 1, wherein the magnetic particles have a median particle size of from 35 to 150 µm.

Claim 9

Dependent Claim 28 words

A resin-coated magnetic carrier according to Claim 1, wherein the resin composition is deposited in an amount of from 0.01 to 10 wt% based on the magnetic particles.

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