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US 8,285,162 B2Granted
Image forming apparatus that includes a first developing device that holds a black developer and a second developing device that holds a gray developer
AssigneeOki Data Corporation
InventorKenji Koido
Life of this patent
Estimating the term…
Abstract
An image forming apparatus includes a plurality of developing devices. Each developing devices performs an electrophotographic process to form an image. The image forming apparatus comprises a first developing device and a second developing device. The first developing device holds a black developer containing a first black coloring agent. The second developing device holds a gray developer. The gray developer contains a second black coloring agent and a coloring agent of a chromatic color. The chromatic color is a complementary color to the second black coloring agent.
Claims23
An image forming apparatus that forms an image on a print medium, the image being formed of developer material, comprising:
- a first image forming unit holding a first developer material, the first developer material containing a first achromatic coloring agent present in a first proportion to the first developer material;
- and
- a second image forming unit holding a second developer material, the second developer material containing a second achromatic coloring agent and a chromatic coloring agent, the second achromatic coloring agent in the second developer material being present in a second proportion smaller than the first proportion,
- wherein the first achromatic coloring agent and the second achromatic coloring agent are a black coloring agent,
- wherein the chromatic coloring agent is a bluish coloring agent.
2 more elements
An image forming apparatus that forms an image on a print medium, the image being formed of developer material, comprising:
- a first image forming unit holding a first developer material, the first developer material containing a first achromatic coloring agent present in a first proportion to the first developer material;
- and
- a second image forming unit holding a second developer material, the second developer material containing a second achromatic coloring agent and a chromatic coloring agent, the second achromatic coloring agent in the second developer material being present in a second proportion smaller than the first proportion,
- wherein the chromatic coloring agent has a color complementary to a shade of color of an image printed using the second achromatic coloring agent.
1 more element
An image forming apparatus that forms an image on a print medium, the image being formed of developer material, comprising:
- a first image forming unit holding a first developer material, the first developer material containing a first achromatic coloring agent present in a first proportion to the first developer material;
- and
- a second image forming unit holding a second developer material, the second developer material containing a second achromatic coloring agent and a chromatic coloring agent, the second achromatic coloring agent in the second developer material being present in a second proportion smaller than the first proportion,
- wherein the chromatic coloring agent contains a coloring agent that corrects a change in shade caused by the second achromatic coloring agent present in the second proportion.
1 more element
An image forming apparatus that forms an image on a print medium, the image being formed of developer material, comprising:
- a first image forming unit holding a first developer material, the first developer material containing a first achromatic coloring agent present in a first proportion to the first developer material;
- and
- a second image forming unit holding a second developer material, the second developer material containing a second achromatic coloring agent and a chromatic coloring agent, the second achromatic coloring agent in the second developer material being present in a second proportion smaller than the first proportion,
- wherein the chromatic coloring agent is a bluish coloring agent,
- wherein the first developer material is a black developer material and the second developer material is a gray developer material,
- wherein the second image forming unit is one of a plurality of second image forming units, each second image forming unit holding a corresponding second developer material with a different shade of gray from the other second image forming units.
3 more elements
An image forming apparatus that forms an image on a print medium, the image being formed of developer material, comprising:
- a first image forming unit holding a first developer material, the first developer material containing a first achromatic coloring agent present in a first proportion to the first developer material;
- and
- a second image forming unit holding a second developer material, the second developer material containing a second achromatic coloring agent and a chromatic coloring agent, the second achromatic coloring agent in the second developer material being present in a second proportion smaller than the first proportion,
- wherein the chromatic coloring agent is a bluish coloring agent,
- wherein the first developer material is a black developer material and the second developer material is a gray developer material,
- wherein a ratio of a density of an image printed using the gray developer material to a density of an image printed using the black developer material is in a range of 0.212 to 0.506.
3 more elements
An image forming apparatus that forms an image on a print medium, the image being formed of developer material, comprising:
- a first image forming unit holding a first developer material, the first developer material containing a first achromatic coloring agent present in a first proportion to the first developer material;
- and
- a second image forming unit holding a second developer material, the second developer material containing a second achromatic coloring agent and a chromatic coloring agent, the second achromatic coloring agent in the second developer material being present in a second proportion smaller than the first proportion,
- wherein the chromatic coloring agent is a bluish coloring agent,
- wherein the first developer material is a black developer material and the second developer material is a gray developer material,
- wherein an image printed using the gray developer material and having a print duty of 100% includes a saturation ΔEab in a L*a*b* color space, the saturation being given by
- ΔEab={(a*)2+(b*)2}1/2≦5
- where
- Δ Eab is saturation,
- L* is lightness value,
- a* is a redness-greenness value, and
- b* is a yellowness-blueness value.
9 more elements
An image forming apparatus that forms an image on a print medium, the image being formed of developer material, comprising:
- a first image forming unit holding a first developer material, the first developer material containing a first achromatic coloring agent present in a first proportion to the first developer material;
- and
- a second image forming unit holding a second developer material, the second developer material containing a second achromatic coloring agent and a chromatic coloring agent, the second achromatic coloring agent in the second developer material being present in a second proportion smaller than the first proportion,
- wherein the second developer material held in the second image forming unit includes a smaller particle diameter than the first developer material held in the first image forming unit.
1 more element
An image forming apparatus that forms an image on a print medium, the image being formed of developer material, comprising:
- a first image forming unit holding a first developer material, the first developer material containing a first achromatic coloring agent present in a first proportion to the first developer material;
- and
- a second image forming unit holding a second developer material, the second developer material containing a second achromatic coloring agent and a chromatic coloring agent, the second achromatic coloring agent in the second developer material being present in a second proportion smaller than the first proportion,
- wherein the first developer material and the second developer material include base particles formed of binding resin containing at least a coloring agent and an external additive added to surfaces of the base particles, the second developer material including a larger amount of the external additive than the first developer material.
1 more element
An image forming apparatus that forms an image on a print medium, the image being formed of developer material, comprising:
- a first image forming unit holding a first developer material, the first developer material containing a first achromatic coloring agent present in a first proportion to the first developer material;
- and
- a second image forming unit holding a second developer material, the second developer material containing a second achromatic coloring agent and a chromatic coloring agent, the second achromatic coloring agent in the second developer material being present in a second proportion smaller than the first proportion,
- wherein the second achromatic coloring agent present in the second proportion in mass parts is in a range of 0.050 to 0.400 of that of the first achromatic coloring agent.
1 more element
An image forming apparatus that forms an image on a print medium, the image being formed of developer material, comprising:
- a first image forming unit holding a first developer material, the first developer material containing a first achromatic coloring agent present in a first proportion to the first developer material;
- and
- a second image forming unit holding a second developer material, the second developer material containing a second achromatic coloring agent and a chromatic coloring agent, the second achromatic coloring agent in the second developer material being present in a second proportion smaller than the first proportion,
- wherein the first developer material is a black developer material and the second developer material is a gray developer material,
- wherein the first developer material held in the first image forming unit and the second developer material held in the second image forming unit are selectively used in accordance with a print duty of an image that should be printed.
2 more elements
An image forming apparatus that forms an image on a print medium, the image being formed of developer material, comprising:
- a first image forming unit holding a first developer material, the first developer material containing a first achromatic coloring agent present in a first proportion to the first developer material;
- and
- a second image forming unit holding a second developer material, the second developer material containing a second achromatic coloring agent and a chromatic coloring agent, the second achromatic coloring agent in the second developer material being present in a second proportion smaller than the first proportion,
- wherein the first developer material is a black developer material and the second developer material is a gray developer material,
- wherein the first developer material held in the first image forming unit and the second developer material held in the second image forming unit are selectively used in accordance with a print density of an image that should be printed.
2 more elements
Dependencies are inferred from the claim text.