Toner, developer, image forming apparatus, and process cartridge

Patent metadata

Field	Value
Publication number	US-9639016-B2
Application number	US-201615051195-A
Country	US
Kind code	B2
Filing date	Feb 23, 2016
Priority date	Mar 6, 2015
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

A toner includes a polyester resin including a polyester resin component A (A) insoluble in tetrahydrofuran; and a polyester resin component B (B) soluble in tetrahydrofuran. The toner has a first glass transition temperature (Tg1st) of from 20° C. to 50° C., measured at a first temperature rising in differential scanning calorimetry (DSC), and satisfies the following formulae (1) and (2):

T =1/{ a /( TgA +273)+ b /( TgB +273)}−273  (1)

T−TgAB >30× a   (2)

wherein a and b represent weight ratios of (A) and (B) to a total weight of (A) and (B), and satisfy the equation a+b=1; and TgA, TgB and TgAB represent second glass transition temperatures (Tg2nd), measured at a second temperature rising in differential scanning calorimetry, of (A), (B), and a mixture of (A) and (B), respectively.

First claim

What is claimed is:

1. A toner comprising a polyester resin, the polyester resin including;
a polyester resin component A insoluble in tetrahydrofuran; and
a polyester resin component B soluble in tetrahydrofuran,
wherein the toner has a first glass transition temperature (Tg1st) of from 20° C. to 50° C., measured at a first temperature rising in differential scanning calorimetry (DSC), and satisfies the following formulae (1) and (2):
T= 1/{ a /( TgA+ 273)+ b /( TgB+ 273)}−273  (1)

T−TgAB> 30× a   (2)

wherein a and b represent weight ratios of the polyester resin component A and the polyester resin component B to a total weight of the polyester resin component A and the polyester resin component B, and satisfy the equation a+b=1; and TgA, TgB and TgAB represent second glass transition temperatures (Tg2nd), measured at a second temperature rising in differential scanning calorimetry, of the polyester resin component A, the polyester resin component B, and a mixture of the polyester resin component A and the polyester resin component B, respectively.

2. The toner of claim 1 , wherein the polyester resin component A comprises a trivalent or tetravalent aliphatic alcohol component having 3 to 10 carbon atoms as a polyol component.

3. The toner of claim 1 , wherein the polyester resin component A includes a diol component, the diol component having a main chain having an odd number of carbon atoms, and the diol component having a side chain having an alkyl group.

4. The toner of claim 1 , wherein the polyester resin component A comprises at least one of urethane bond and urea bond.

5. The toner of claim 1 , wherein the polyester resin component B comprises a trivalent or tetravalent aliphatic alcohol component having 3 to 10 carbon atoms as a polyol component.

6. The toner of claim 1 , wherein a difference in weight-average molecular weight between the polyester resin component A and the polyester resin component B is 50,000 or less, and a difference in number-average molecular weight between the polyester resin component A and the polyester resin component B is 5,000 or less.

7. The toner of claim 1 , wherein the component A comprises a dicarboxylic acid component as a polycarboxylic acid component, and the dicarboxylic acid component comprises an aliphatic dicarboxylic acid having 4 to 12 carbon atoms.

8. The toner of claim 1 , wherein the toner has a second glass transition temperature (Tg2nd) of from 0° C. to 30° C., measured at a second temperature rising in differential scanning calorimetry, and satisfies the following relation:
Tg 1 st−Tg 2 nd> 10° C.

9. A developer comprising the toner according to claim 1 .

10. An image forming apparatus, comprising:
an electrostatic latent image bearer;
an electrostatic latent image former to form an electrostatic latent image on the electrostatic latent image bearer; and
an image developer to develop the electrostatic latent image with the toner according to claim 1 to form a toner image.

11. A process cartridge detachably mountable on image forming apparatus, comprising:
an electrostatic latent image bearer; and
an image developer to develop an electrostatic latent image formed on an electrostatic latent image bearer with the toner according to claim 1 to form a toner image.

Assignees

• Sugimoto Tsuyoshi
• Nakayama Shinya
• Yamada Hiroshi
• Santo Hideyuki
• Hasegawa Shin
• Karato Suzuka
• Nagata kohsuke
• Ohnuma Koh
• Ricoh Co Ltd

Inventors

• Sugimoto Tsuyoshi
• Nakayama Shinya
• Yamada Hiroshi
• Santo Hideyuki
• Hasegawa Shin
• Karato Suzuka
• Nagata kohsuke
• Ohnuma Koh

Classifications

• C08G18/755

  and at least one isocyanate or isothiocyanate group linked to a secondary carbon atom of the cycloaliphatic ring, e.g. isophorone diisocyanate · CPC title

• G03G9/08755 Primary

  Polyesters · CPC title

• C08L67/00

  Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain (of polyester-amides C08L77/12; of polyester-imides C08L79/08); Compositions of derivatives of such polymers · CPC title

• C08G18/4219

  from aromatic dicarboxylic acids and dialcohols in combination with polycarboxylic acids and/or polyhydroxy compounds which are at least trifunctional · CPC title

• C08G18/4247

  derived from polyols containing at least one ether group and polycarboxylic acids · CPC title