Developing agent and image forming apparatus
AssigneesKabushiki Kaisha Toshiba, Toshiba Tec Kabushiki Kaisha
InventorTakahito Kabai
Life of this patent
Estimating the term…
Abstract
The softening point of the binder resin and the thickness of the rubber layer of the fixing roller are optimized and thus it becomes possible to form a high-quality full-color image at a low cost.
Claims15
A developing agent that is used in combination with a fixing device comprising a thermal fixing roller including a metal roller, a rubber layer provided on a surface of the metal roller and having a rubber hardness defined by JIS A of 3° or more and less than 5°, and a press roller provided to face the thermal fixing roller, wherein the developing agent contains a coloring agent and a binder resin, a softening point of the binder resin and a thickness of the rubber layer satisfying a relationship represented by the following formula:
- y≧10−6x4−0.0007x3+0.1217x2−9.9932x+314.31 (1)
- where
- y:
- the thickness of the rubber layer (mm), and
- x:
- the softening point (° C.) of the binder resin.
A developing agent that is used in combination with a fixing device comprising a thermal fixing roller including a metal roller, a rubber layer provided on a surface of the metal roller and having a rubber hardness defined by JIS A of 3° or more and less than 8°, and a press roller provided to face the thermal fixing roller, wherein the developing agent contains a coloring agent and a binder resin, a softening point of the binder resin and a thickness of the rubber layer satisfying a relationship represented by the following formula:
- y≧10−6x4−0.0004x3+0.0774x2−6.2789x+200.34 (2)
- where
- y:
- the thickness of the rubber layer (mm), and
- x:
- the softening point (° C.) of the binder resin.
The developing agent according to claim 7, wherein the thickness of the rubber layer is 0.1 to 1.0 mm.
A method of fixing a developing agent used in combination with a fixing device comprising:
- a thermal fixing roller including a metal roller, a rubber layer provided on a surface of the metal roller and a resin coating layer provided on the rubber layer;
- and
- a press roller provided to face the thermal fixing roller,
- wherein a softening point of a binder resin and a thickness of the rubber layer satisfies a relationship represented by the following formula (1) or (2):
- when a rubber hardness defined by JIS A is 3° or more and less than 5°,
- y≧10−6x4−0.0007x3+0.1217x2−9.9932x+314.31 (1)or
- when a rubber hardness defined by JIS A is 5° to 8°,
- y≧10−6x4−0.0004x3+0.0774x2−6.2789x+200.34 (2)
- where
- y:
- the thickness of the rubber layer (mm), and
- x:
- the softening point (0°C.) of the binder resin.
Dependencies are inferred from the claim text.