IP Library Granted Patent US 7,960,083
Granted Patent B2
US 7,960,083 · App. 12/142,311 · Granted Jun 14, 2011

Image forming apparatus, image forming method, and process cartridge

Assignee: Ricoh Company, Ltd.
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Quick Facts
Patent No.
US 7,960,083
App. No.
12/142,311
Granted
Jun 14, 2011
Kind
B2
Abstract

An image forming apparatus including a charging unit, an exposing unit, a developing unit, a transferring unit, and a fixing unit. A toner containing a colorant and a binder resin which contains a polyester resin (A) and a polyester resin (B) having a softening point 10° C. or more higher than that of the polyester resin (A); the polyester resin (A) is a (meth)acrylic acid-modified rosin derived resin having a polyester unit obtained by polycondensation of an alcohol component, which contains 65 mol % or more of 1,2-propanediol in a dihydric alcohol component, and a carboxylic acid component containing a (meth)acrylic acid-modified rosin; the polyester resin (B) is a purified rosin derived resin having a polyester unit obtained by polycondenstation of an alcohol component, which contains a total of 70 mol % or more of 1,2-propanediol and 1,3-propanediol in a dihydric alcohol component, and a carboxylic acid component containing purified rosin.

Claims (9)

1. An image forming method, comprising steps of:

charging a surface of a latent electrostatic image bearing member;

exposing the surface, which is charged, of the latent electrostatic image bearing member to form a latent electrostatic image;

developing the latent electrostatic image with a toner to form a visible image;

transferring the visible image onto a recording medium; and

fixing the image on the recording medium,

wherein the toner comprises at least a binder resin and a colorant, and the binder resin comprises a polyester resin (A) and a polyester resin (B) which has a softening point 10° C. or more higher than that of the polyester resin (A),

the polyester resin (A) is a (meth)acrylic acid-modified rosin derived resin having a polyester unit obtained by polycondensation of an alcohol component and a carboxylic acid component, the alcohol component containing 65 mol % or more of 1,2-propanediol in a dihydric alcohol component, and the carboxylic acid component containing a (meth)acrylic acid-modified rosin, and

the polyester resin (B) is a purified rosin derived resin having a polyester unit obtained by polycondensation of an alcohol component and a carboxylic acid component, the alcohol component containing a total of 70 mol % or more of 1,2-propanediol and 1,3-propanediol in a dihydric alcohol component, and the carboxylic acid component containing a purified rosin.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 19, 2008
From: NAKAYAMA, SHINYA; KOTSUGAI, AKIHIRO; SABU, AKIYOSHI
To: RICOH COMPANY, LTD.
Reel/Frame 021132/0121 →
Priority Claims (1)
JP 2007-163201 · Jun 20, 2007 · national
Continuity (1)
Related Publication 20080318143A1 · Dec 25, 2008