US5497225A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Color image forming apparatus having a plurality of drums for a plurality of colors
Assignee: Fujitsu Ltd
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Filing: 1994-08-29
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Granted: 1996-03-05
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Expires: 2014-08-29
Abstract
Abstract A color image forming apparatus for forming a color image on a sheet by use of a plurality of photosensitive drums. The plurality of photosensitive drums correspond to a plurality of colors and have eccentric phases each shifted by a quantity corresponding to a radius of the photosensitive drum and a distance between transfer positions of the photosensitive drums. The color image forming apparatus also includes a plurality of charging units which correspond to the respective photosensitive drums, for charging the photosensitive drums. An exposure light source effects an image exposure on each photosensitive drum. A plurality of developing units correspond to the respective photosensitive drums, for forming toner images on the photosensitive drums by developing electrostatic latent images on the photosensitive drums. A plurality of transferring units, corresponding to the respective photosensitive drums, transfer the toner images on the photosensitive drums onto the sheet. The eccentric phases of the plurality of photosensitive drums are set the same on the basis of the sheet to be fed, and a color deviation of each color on the sheet can be thereby prevented.
Inventors
- 👤 Masato Matsuzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:15
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/50; H04N1/506; G; G03; G03G; G03G15/00; G03G15/01; G03G15/0142; G03G15/0178; G03G15/0194; B; B41; B41J; B41J2/00; B41J2/435; B41J2/447; B41J2/455; G03G2215/00; G03G2215/01; G03G2215/0103; G03G2215/0119
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
135 words
A color image forming apparatus for forming a multi-color image on a sheet, comprising: a plurality of photosensitive drums provided corresponding to a plurality of colors and having eccentric phases each shifted by a quantity corresponding to a radius of each of said photosensitive drums and a distance between transfer positions of said photosensitive drums; a plurality of charging units, provided corresponding to said photosensitive drums, for charging said photosensitive drums; an exposing source for effecting an image exposure on said photosensitive drums; a plurality of developing units, provided corresponding to said photosensitive drums, for forming toner images on said photosensitive drums by developing electrostatic latent images on said photosensitive drums; and a plurality of transferring units, provided corresponding to said photosensitive drums, for transferring the toner images on said photosensitive drums onto the sheet.
Claim 2
Dependent Claim
135 words
A color image forming apparatus for forming a multi-color image on a sheet, comprising: a plurality of photosensitive drums provided corresponding to a plurality of colors and having eccentric phases each shifted by a quantity corresponding to a radius of each of said photosensitive drums and a distance between transfer positions of said photosensitive drums; a plurality of charging units, provided corresponding to said photosensitive drums, for charging said photosensitive drums; an exposing source for effecting an image exposure on said photosensitive drums; a plurality of developing units, provided corresponding to said photosensitive drums, for forming toner images on said photosensitive drums by developing electrostatic latent images on said photosensitive drums; and a plurality of transferring units, provided corresponding to said photosensitive drums, for transferring the toner images on said photosensitive drums onto the sheet.
Claim 3
Dependent Claim
27 words
The color image forming apparatus according to claim 1, further comprising endless feeding means for feeding a plurality of the sheets in series to said transferring units.
Claim 4
Dependent Claim
41 words
The color image forming apparatus according to claim 2, a deviation quantity of an eccentric phase between adjacent ones of said photosensitive drums is a value of an integral multiple of 2π/n (where n is the number of said photosensitive drums).
Claim 5
Dependent Claim
25 words
The color image forming apparatus according to claim 3, wherein the deviation quantity of an eccentric phase between said adjacent photosensitive drums is 180 degrees.
Claim 6
Dependent Claim
27 words
The color image forming apparatus according to claim 4, wherein a peripheral length of each of said photosensitive drums is twice a distance between said transferring units.
Claim 7
Dependent Claim
25 words
The color image forming apparatus according to claim 3, wherein the deviation quantity of an eccentric phase between said adjacent photosensitive drums is 90 degrees.
Claim 8
Dependent Claim
30 words
The color image forming apparatus according to claim 6, wherein a peripheral length of each of said photosensitive drums is four times greater than a distance between said transferring units.
Claim 9
Dependent Claim
20 words
The color image forming apparatus according to claim 2, wherein said endless feeding means is constructed of belt-based feeding means.
Claim 10
Dependent Claim
26 words
The color image forming apparatus according to claim 8, wherein said belt is composed of an electrostatic adsorption belt for adsorbing static electricity from the sheet.
Claim 11
Dependent Claim
42 words
The color image forming apparatus according to claim 8, wherein a deviation quantity of an eccentric phase between adjacent ones of said photosensitive drums is a value of an integral multiple of 2π/n (wherein n is the number of said photosensitive drums).
Claim 12
Dependent Claim
25 words
The color image forming apparatus according to claim 10, wherein the deviation quantity of an eccentric phase between said adjacent photosensitive drums is 180 degrees.
Claim 13
Dependent Claim
27 words
The color image forming apparatus according to claim 11, wherein a peripheral length of each of said photosensitive drums is twice a distance between said transferring units.
Claim 14
Dependent Claim
25 words
The color image forming apparatus according to claim 10, wherein the deviation quantity of an eccentric phase between said adjacent photosensitive drums is 90 degrees.
Claim 15
Dependent Claim
30 words
The color image forming apparatus according to claim 13, wherein a peripheral length of each of said photosensitive drums is four times greater than a distance between said transferring units.
Claim 16
Dependent Claim
40 words
The color image forming apparatus according to claim 1, wherein each of said photosensitive drums includes a drum base formed with a photosensitive layer along its periphery and a pair of flanges fitted into two side-portions of said drum base.
Claim 17
Dependent Claim
27 words
The color image forming apparatus according to claim 15, further comprising endless feeding means for feeding a plurality of the sheets in series to said transferring units.
Claim 18
Dependent Claim
41 words
The color image forming apparatus according to claim 16, a deviation quantity of an eccentric phase between adjacent ones of said photosensitive drums is a value of an integral multiple of 2π/n (where n is the number of said photosensitive drums).
Claim 19
Dependent Claim
25 words
The color image forming apparatus according to claim 17, wherein the deviation quantity of an eccentric phase between said adjacent photosensitive drums is 90 degrees.
Claim 20
Dependent Claim
24 words
The color image forming apparatus according to claim 17, wherein the deviation quantity of an eccentric phase between said photosensitive drums is 180 degrees.
Claim 21
Dependent Claim
27 words
The color image forming apparatus according to claim 19, wherein a peripheral length of each of said photosensitive drums is twice a distance between said transferring units.
Claim 22
Dependent Claim
30 words
The color image forming apparatus according to claim 19, wherein a peripheral length of each of said photosensitive drums is four times greater than a distance between said transferring units.
Claim 23
Dependent Claim
27 words
The color image forming apparatus according to claim 1, wherein said exposing source comprises a plurality of image exposing means provided for each of said photosensitive drums.
Claim 24
Dependent Claim
27 words
The color image forming apparatus according to claim 22, further comprising endless feeding means for feeding a plurality of the sheets in series to said transferring units.
Claim 25
Dependent Claim
41 words
The color image forming apparatus according to claim 23, a deviation quantity of an eccentric phase between adjacent one of said photosensitive drums is a value of an integral multiple of 2π/n (where n is the number of said photosensitive drums).
Claim 26
Dependent Claim
24 words
The color image forming apparatus according to claim 24, wherein the deviation quantity of an eccentric phase between adjacent photosensitive drums is 180 degrees.
Claim 27
Dependent Claim
27 words
The color image forming apparatus according to claim 25, wherein a peripheral length of each of said photosensitive drums is twice a distance between said transferring units.
Claim 28
Dependent Claim
24 words
The color image forming apparatus according to claim 24, wherein the deviation quantity of an eccentric phase between adjacent photosensitive drums is 90 degrees.
Claim 29
Dependent Claim
30 words
The color image forming apparatus according to claim 27, wherein a peripheral length of each of said photosensitive drums is four times greater than a distance between said transferring units.
References Cited (Backward Citations)
US4531828A
Cited
US4690542A
Cited
US4752804A
Cited
US4796050A
Cited
JPH03149576A
Cited
JPH03293679A
Cited
US5287160A
Cited
US5243396A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-03-05 | 1999-09-04 | 2000-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-03-05 | 2003-09-04 | 2004-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-03-05 | 2007-09-04 | 2008-03-05 | $7700.00 | Window Closed / Lapsed |