TONER, DEVELOPER, AND IMAGE FORMING METHOD

• US 20080318144A1
• Filed: 06/20/2008
• Published: 12/25/2008
• Est. Priority Date: 06/22/2007
• Status: Abandoned Application

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Yamashita, Hiroshi, Sugimoto, Tsuyoshi, Watanabe, Naohiro, Wakamatsu, Shinichi
• Application Number:
  US12/143,244
• Publication Number:
  US 20080318144A1
• Time in Patent Office: Days
• US Class Current: 430/48
• CPC Class Codes: G03G 2215/0609 magnetic brush
• CPC Class Codes: G03G 9/0806 whereby chemical synthesis of at least one of the toner components takes place
• CPC Class Codes: G03G 9/081 by mixing the toner components in a liquefied state; melt kneading; reactive mixing
• CPC Class Codes: G03G 9/0918 Phthalocyanine dyes
• CPC Class Codes: G03G 9/0926 characterised by physical or chemical properties

Abstract

To provide a toner including: a toner material that contains at least a binder resin, a pigment, and a pigment dispersant, wherein the pigment dispersant has an acid value of 20 mgKOH/g to 50 mgKOH/g and an amine value of 1 mgKOH/g to 50 mgKOH/g, and wherein the pigment contains at least aluminum phthalocyanine.

Claims

1. A toner comprising:

a toner material that contains at least a binder resin, a pigment, and a pigment dispersant,

wherein the pigment dispersant has an acid value of 20 mgKOH/g to 50 mgKOH/g and an amine value of 1 mgKOH/g to 50 mgKOH/g, and

wherein the pigment contains at least aluminum phthalocyanine.

2. The toner according to claim 1, wherein the pigment dispersant contains at least one of a polyester-based pigment dispersant, an acrylic pigment dispersant, and a polyurethane-based pigment dispersant.

3. The toner according to claim 1, wherein the pigment dispersant has a melting point of 20°

C. to 80°

C.

4. The toner according to claim 1, wherein the amount of the pigment dispersant is 1 part by mass to 100 parts by mass per 100 parts by mass of the pigment.

5. The toner according to claim 1, wherein the pigment further contains copper phthalocyanine, and the mass ratio of the copper phthalocyanine to the aluminum phthalocyanine is 40:

60 to 90;

10.

6. The toner according to claim 1, wherein the toner material further contains a wax.

7. The toner according to claim 1, wherein the toner material further contains a binder resin precursor and a wax.

8. The toner according to claim 1, wherein the toner is produced by a method which comprises:

dispersing or emulsifying in an aqueous medium an oil phase containing the toner material, to produce particles; and

aggregating the particles.

9. The toner according to claim 1, wherein the toner is produced by a method which comprises:

adding in an aqueous medium a dispersion liquid and an oil phase, the dispersion liquid containing a binder resin precursor composed of a modified polyester resin, the oil phase containing a fine particle dispersant;

dissolving a compound that is crosslinkable with the binder resin precursor;

dispersing the oil phase in the aqueous medium to prepare an emulsified dispersion liquid; and

allowing the binder resin precursor to undergo crosslinking reaction or extension reaction in the emulsified dispersion liquid.

10. The toner according to claim 5, wherein the copper phthalocyanine and aluminum phthalocyanine are mixed together by solvent salt milling.

11. The toner according to claim 5, wherein the toner is produced by dry-mixing the toner material followed by melt-kneading.

12. The toner according to claim 11, wherein in the toner material the copper phthalocyanine and aluminum phthalocyanine are mixed together in the form of powder.

13. A developer comprising:

a toner which comprises a toner material that contains at least a binder resin, a pigment, and a pigment dispersant, wherein the pigment dispersant has an acid value of 20 mgKOH/g to 50 mgKOH/g and an amine value of 1 mgKOH/g to 50 mgKOH/g, and wherein the pigment contains at least aluminum phthalocyanine.

14. An image forming method comprising:

forming a latent electrostatic image on a latent electrostatic image bearing member;

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

transferring the visible image to a recording medium; and

fixing the image to the recording medium,

wherein the toner comprises a toner material that contains at least a binder resin, a pigment, and a pigment dispersant, wherein the pigment dispersant has an acid value of 20 mgKOH/g to 50 mgKOH/g and an amine value of 1 mgKOH/g to 50 mgKOH/g, and wherein the pigment contains at least aluminum phthalocyanine.