Toner, and image forming method, process cartridge, and image forming apparatus using the toner

Patent metadata

Field	Value
Publication number	US-9709912-B2
Application number	US-201314042993-A
Country	US
Kind code	B2
Filing date	Oct 1, 2013
Priority date	Nov 29, 2012
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A toner is provided. The toner includes a crystalline resin and a non-crystalline resin, and has a thermal property such that when the toner is heated after being firstly heated to 60° C. followed by cooling in differential scanning calorimetry (DSC), the toner has a clear peak specific to melting of the crystalline resin at a temperature T1, and when the toner is heated after being firstly heated to 80° C. followed by cooling in the differential scanning calorimetry (DSC), the toner does not have a clear peak specific to melting of the crystalline resin at a temperature not higher than the temperature T1.

First claim

What is claimed is:

1. A toner, comprising:
a crystalline binder resin; and
a non-crystalline binder resin,
wherein:
a glass transition temperature of all the non-crystalline binder resin is not lower than 55° C.;
the toner has a thermal property such that when the toner is heated to 150° C. for 60 minutes after being firstly heated from 30° C. to 60° C. followed by cooling from 60° C. to 0° C. in differential scanning calorimetry (DSC), the toner has a clear peak specific to melting of the crystalline resin at a temperature T1, and when the toner is heated to 150° C. for 60 minutes after being firstly heated from 30° C. to 80° C. followed by cooling from 80° C. to 0° C. in the differential scanning calorimetry (DSC), no peak can be observed specific to melting of the crystalline resin at a temperature not higher than T1;
the melting point (endothermic peak temperature) of the crystalline binder resin is from 60° C. to 70° C.;
the crystalline binder resin has an average particle diameter of not greater than 0.9 μm as dispersed in the toner; and
the non-crystalline binder resin has a weight average molecular weight ranging from 1,000 to 10,000.

2. The toner according to claim 1 , wherein the toner has a thermal property such that when the toner is heated to 150° C. for 60 minutes after being firstly heated from 30° C. to 60° C. followed by cooling from 60° C. to 0° C. in differential scanning calorimetry (DSC), the toner has a clear peak specific to melting of the crystalline resin at a temperature T1, and when the toner is heated to 150° C. for 60 minutes after being firstly heated from 30° C. to 70° C. followed by cooling from 70° C. to 0° C. in the differential scanning calorimetry (DSC), the toner has no clear peak specific to melting of the crystalline resin at a temperature not higher than the temperature T1.

3. An image forming method, comprising:
forming an electrostatic latent image on an image bearing member; and
developing the electrostatic latent image with a developer including the toner according to claim 1 to form a toner image on the image bearing member.

4. The toner according to claim 1 , wherein the average particle diameter of the crystalline binder resin dispersed in the toner ranges from 0.41 to 0.9 μm.

Assignees

• Fuwa Kazuoki
• Kadota Takuya
• Mikuriya Yoshihiro
• Nozaki Tsuyoshi
• Ishikawa Yoshimichi
• Takeuchi Yuta
• Fukao Tomohiro
• Miki Tomoharu
• Nakamura Takayuki
• Ricoh Co Ltd

Inventors

• Fuwa Kazuoki
• Kadota Takuya
• Mikuriya Yoshihiro
• Nozaki Tsuyoshi
• Ishikawa Yoshimichi
• Takeuchi Yuta
• Fukao Tomohiro
• Miki Tomoharu
• Nakamura Takayuki

Classifications

• G03G9/08755

  Polyesters · CPC title

• G03G13/06

  Developing · CPC title

• G03G9/08797 Primary

  characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature · CPC title

• G03G9/08795

  characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants · CPC title

• G03G13/08

  using a solid developer, e.g. powder developer · CPC title