DEVELOPING ROLLER

• US 20120237270A1
• Filed: 03/16/2012
• Published: 09/20/2012
• Est. Priority Date: 03/18/2011
• Status: Abandoned Application

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Nozaki, Chiyoshi, Yasunaga, Hideaki, Nakagawa, Shuuichi, JURI, Keiichiro
• Application Number:
  US13/422,739
• Publication Number:
  US 20120237270A1
• Time in Patent Office: Days
• US Class Current: 399/284
• CPC Class Codes: G03G 15/0818 characterised by the structure of the donor member, e.g. surface properties

Abstract

A developing roller including: an electrically-conductive base; an elastic layer formed on an outer circumference of the electrically-conductive base; and a toner bearing layer formed on the elastic layer, wherein the toner bearing layer contains a polyurethane resin having an isocyanurate structure, and wherein the polyurethane resin has a ratio A/B of 1.0 to 10.0 where A denotes absorbance attributed to C═O of cyanurate and B denotes absorbance attributed to C═O of urethane in an infrared absorption spectrum of the polyurethane resin obtained by an ATR method.

Claims

1. A developing roller comprising:

an electrically-conductive base;

an elastic layer formed on an outer circumference of the electrically-conductive base; and

a toner bearing layer formed on the elastic layer,

wherein the toner bearing layer contains a polyurethane resin having an isocyanurate structure, and

wherein the polyurethane resin has a ratio A/B of 1.0 to 10.0 where A denotes absorbance attributed to C═

O of cyanurate and B denotes absorbance attributed to C═

O of urethane in an infrared absorption spectrum of the polyurethane resin obtained by an ATR method.

2. The developing roller according to claim 1, wherein the polyurethane resin is a polymer of polyol and polyisocyanate prepolymer forming an isocyanurate compound.

3. The developing roller according to claim 2, wherein a ratio NCO/OH by mole of NCO groups in the polyisocyanate prepolymer to OH groups in the polyol is 8 to 108.

4. The developing roller according to claim 2, wherein the polyisocyanate prepolymer contains at least one selected from the group consisting of methylene diphenyl diisocyanate (MDI), tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), naphthylene-1,5-diisocyanate (NDI), tetramethyl xylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate (H₆XDI), dicyclohexyl methane diisocyanate (H₁₂MDI), hexamethylene diisocyanate (HDI), dimer acid diisocyanate (DDI), norbornene diisocyanate (NBDI), trimethyl hexamethylene diisocyanate (TMDI), and isocyanurate compounds thereof.

5. The developing roller according to claim 4, wherein the polyisocyanate prepolymer contains at least one selected from the group consisting of tolylene diisocyanate, hexamethylene diisocyanate, and isocyanurate compounds thereof.

6. A developing device comprising:

a developing roller configured to bear on a surface thereof a developer to be supplied to a latent image bearing member;

a developer supplying member configured to supply the developer onto the surface of the developing roller;

a developer layer regulating member configured to form a thin layer of the developer on the surface of the developing roller, and

a developer container which houses the developer,

wherein the developing roller comprises;

an electrically-conductive base,

an elastic layer formed on an outer circumference of the electrically-conductive base, and

a toner bearing layer formed on the elastic layer,

wherein the toner bearing layer contains a polyurethane resin having an isocyanurate structure, and

wherein the polyurethane resin has a ratio A/B of 1.0 to 10.0 where A denotes absorbance attributed to C═

O of cyanurate and B denotes absorbance attributed to C═

O of urethane in an infrared absorption spectrum of the polyurethane resin obtained by an ATR method.

7. An image forming apparatus comprising:

a latent image bearing member;

a charging unit configured to charge a surface of the latent image bearing member;

an exposing unit configured to expose the charged surface of the latent image bearing member to light to form an electrostatic latent image;

a developing unit configured to develop the electrostatic latent image with a developer to form a visible image;

a transfer unit configured to transfer the visible image to a recording medium; and

a fixing unit configured to fix the transferred image on the recording medium,

wherein the developing unit is a developing device which comprises;

a developing roller configured to bear on a surface thereof the developer to be supplied to the latent image bearing member;

a developer supplying member configured to supply the developer onto the surface of the developing roller;

a developer layer regulating member configured to form a thin layer of the developer on the surface of the developing roller, and

a developer container which houses the developer,

wherein the developing roller comprises;

an electrically-conductive base;

an elastic layer formed on an outer circumference of the electrically-conductive base; and

a toner bearing layer formed on the elastic layer,

wherein the toner bearing layer contains a polyurethane resin having an isocyanurate structure, and

wherein the polyurethane resin has a ratio A/B of 1.0 to 10.0 where A denotes absorbance attributed to C═

O of cyanurate and B denotes absorbance attributed to C═

O of urethane in an infrared absorption spectrum of the polyurethane resin obtained by an ATR method.