Patent EP0426435A2 successfully refreshed from Google Patents.
EP0426435A2
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EP
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Image forming apparatus for halftone reproduction
Assignee: Canon Inc
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Filing: 1990-10-30
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Granted: —
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Expires: 2010-10-30
Abstract
Abstract An image forming apparatus suitable for use in a laser beam printer includes an image forming unit for forming an image on a photoconductor (8), and a reproduction unit for reproducing a high density image and a halftone image on the photoconductor. A detector (2) then detects the density of the high density image and the halftone image formed on the photoconductor. A controller (1) controls an image forming condition of the image forming unit based on a detection result by the detector.
Inventors
- 👤 Hiromichi Yamada
- 👤 Masaharu Ohkubo
- 👤 Masaki Ojima
- 👤 Hiroshi Sasame
- 👤 Takashi Kawana
- 👤 Kaoru Seto
- 👤 Hiroshi Mano
- 👤 Tetsuo Saito
- 👤 Atsushi Kashihara
- 👤 Michio Ito
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 10:32
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4055; H04N1/4056; H04N1/407; H04N1/4076; H04N1/4078
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
78 words
An image forming apparatus comprising: image forming means for forming an image on an image bearing member; reproduction means for reproducing a high density image and a halftone image on the image bearing member; detecting means for detecting the density of the high density image and the halftone image formed on the image bearing member; and control means for controlling an image forming condition of said image forming means based on a detection result by said detecting means.
Claim 2
Dependent Claim
78 words
An image forming apparatus comprising: image forming means for forming an image on an image bearing member; reproduction means for reproducing a high density image and a halftone image on the image bearing member; detecting means for detecting the density of the high density image and the halftone image formed on the image bearing member; and control means for controlling an image forming condition of said image forming means based on a detection result by said detecting means.
Claim 3
Dependent Claim
58 words
An image forming apparatus according to claim 1, wherein said control means further comprises calculation means for calculating a density ratio between the high density image and the halftone image based on the detection result by said detecting means, and wherein said controls means controls the image forming condition based on the density ratio and a predetermined value.
Claim 4
Dependent Claim
21 words
An image forming apparatus according to claim 1, wherein said reproduction means reproduces the halftone image based on a pulse-width-modulated signal.
Claim 5
Dependent Claim
41 words
An image forming apparatus according to claim 1, further comprising input means for inputting an image signal, wherein said image forming means includes beam generating means for generating a beam in accordance with the image signal input from said input means.
Claim 6
Dependent Claim
58 words
An image forming apparatus according to claim 4, wherein said image forming means includes developing means for developing the image formed on the image bearing member, and wherein said control means controls at least one of the developing bias of said developing means and the drive current of said beam generating means for controlling the image forming condition.
Claim 7
Dependent Claim
73 words
An image forming apparatus comprising: image forming means for forming an image on an image bearing member; pattern generation means for generating a predetermined pattern, wherein said image forming means forms a halftone image based on the predetermined pattern generated by said pattern generation means; detecting means for detecting the density of the halftone image; and adjusting means for adjusting the image forming means based on a detection result by said detecting means.
Claim 8
Dependent Claim
73 words
An image forming apparatus comprising: image forming means for forming an image on an image bearing member; pattern generation means for generating a predetermined pattern, wherein said image forming means forms a halftone image based on the predetermined pattern generated by said pattern generation means; detecting means for detecting the density of the halftone image; and adjusting means for adjusting the image forming means based on a detection result by said detecting means.
Claim 9
Dependent Claim
66 words
An image forming apparatus according to claim 6, wherein said image forming means forms a solid image based on the predetermined pattern generated by said pattern generation means, and wherein said detecting means detects the density of the solid image, and said adjusting means adjusts the image forming means based on the density of the halftone image and the solid image detected by said detecting means.
Claim 10
Dependent Claim
73 words
An image forming apparatus according to Claim 7, wherein said image forming means further comprises a charger for charging the image bearing member, developing means for developing the image formed on the image bearing member, a beam generating means for generating a beam, wherein said adjusting means adjusts at least one of the output of said charger, the developing bias of said developing means and the light quantity of the beam generating means.
Claim 11
Dependent Claim
51 words
An image forming apparatus according to Claim 8, wherein said image forming means further comprises input means for inputting image data, and converting means for converting the image data input from said input means and outputting converted image data, wherein said adjusting means adjusts a conversion mode of said converting means.
Claim 12
Dependent Claim
50 words
A recording apparatus comprising: input means for inputting a pulse-width-modulated signals sent from an external host device; correction means for correcting the pulse-width of the pulse-width-modulated signal input from said input means; and recording means for recording an image in accordance with the pulse-width-modulated signal corrected by said correction means.
Claim 13
Dependent Claim
50 words
A recording apparatus comprising: input means for inputting a pulse-width-modulated signals sent from an external host device; correction means for correcting the pulse-width of the pulse-width-modulated signal input from said input means; and recording means for recording an image in accordance with the pulse-width-modulated signal corrected by said correction means.
Claim 14
Dependent Claim
25 words
A recording apparatus recording to Claim 10, wherein said correction means includes a manual correction means for correcting the pulse-width of the pulse-width-modulated signal manually.
Claim 15
Dependent Claim
69 words
A recording apparatus according to Claim 10, further comprising command signal input means for inputting a command signal sent from the external host device, and discrimination means for discriminating a correction mode of the pulse-width in accordance with the command signal input from said command signal input means, wherein said correction means corrects the pulse-width of the pulse-width-modulated signal in accordance with a discrimination result by said discrimination means.
Claim 16
Dependent Claim
44 words
A recording apparatus according to claim 10, further comprising environment condition detecting means for detecting an environment condition in the apparatus, wherein said correction means corrects the pulse-width of the pulse-width-modulated signal in accordance with a detection result by said environment condition detecting means.
Claim 17
Dependent Claim
24 words
A recording apparatus according to claim 13, wherein said environment condition detecting means includes a temperature detector for detecting a temperature in the apparatus.
Claim 18
Dependent Claim
56 words
An image forming apparatus comprising image forming means for forming an image on an image bearing member utilizing a bias voltage, the apparatus being arranged to generate high density images and half tone images, characterised by control means to maintain the density of the half tone images at a predetermined level by varying said bias voltage.
Claim 19
Dependent Claim
56 words
An image forming apparatus comprising image forming means for forming an image on an image bearing member utilizing a bias voltage, the apparatus being arranged to generate high density images and half tone images, characterised by control means to maintain the density of the half tone images at a predetermined level by varying said bias voltage.
Claim 20
Independent Claim
28 words
A method of printing half tone images comprising monitoring the image density and controlling the image writing apparatus so as to maintain the half tone density substantially constant.
Claim 21
Independent Claim
28 words
A method of printing half tone images comprising monitoring the image density and controlling the image writing apparatus so as to maintain the half tone density substantially constant.
Claim 22
Dependent Claim
11 words
A printer including an image sensor controlling the print image density.
Claim 23
Dependent Claim
11 words
A printer including an image sensor controlling the print image density.
References Cited (Backward Citations)
No citation records indexed.
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