US5055860A
Expired / Lapsed
US
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Image forming apparatus
Assignee: Ricoh Co Ltd
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Filing: 1990-05-18
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Granted: 1991-10-08
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Expires: 2010-05-18
Abstract
Abstract An image forming apparatus for forming an image by deflecting a light beam signal modulated by an image signal onto a photoconductive element by a polygonal mirror to electrostatically form a latent image and developing the latent image. A main scanning synchronization detector is located in the vicinity of the photoconductive element for setting up synchronization in the main scanning direction. A displacement detector detects a distance over which the photoconductive element has been displaced over a period of time associated with a subscanning pitch. Correcting control is driven in response to the output signals of the main scanning synchronization detector and displacement detector. The light beam signal is so deflected in the subscanning direction as to correct an error in the subscanning pitch.
Inventors
- 👤 Kazunori Bannai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 08:40
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/04; H04N1/047; H04N1/0473; G; G06; G06K; G06K15/00; G06K15/02; G06K15/12; G06K15/1204; G06K15/1219; H04N1/113; H04N1/1135; H04N1/12; H04N2201/00; H04N2201/024; H04N2201/02406; H04N2201/02439; H04N2201/04; H04N2201/047; H04N2201/04701; H04N2201/0471; H04N2201/04715; H04N2201/04724; H04N2201/04734; H04N2201/04744; H04N2201/04753; H04N2201/04756; H04N2201/04758; H04N2201/0476; H04N2201/04793; H04N2201/04794
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
138 words
An image forming apparatus for forming an image by modulating a light beam signal by an image signal, deflecting said modulated light beam signal onto a photoconductive element by a polygonal mirror to electrostatically form a latent image, and developing said latent image, said apparatus comprising: main scanning synchronization detecting means for detecting synchronization of main scanning; driving means for driving the photoconductive element in response to an output of said main scanning synchronization detecting means representative of synchronization; detecting means for detecting a distance which the photoconductive element driven by said driving means moves; comparing means for comparing an output of said detecting means with a predetermined value to output an error signal; and deflecting means for deflecting the light beam signal in a subscanning direction in response to said error signal produced by said comparing means.
Claim 2
Dependent Claim
138 words
An image forming apparatus for forming an image by modulating a light beam signal by an image signal, deflecting said modulated light beam signal onto a photoconductive element by a polygonal mirror to electrostatically form a latent image, and developing said latent image, said apparatus comprising: main scanning synchronization detecting means for detecting synchronization of main scanning; driving means for driving the photoconductive element in response to an output of said main scanning synchronization detecting means representative of synchronization; detecting means for detecting a distance which the photoconductive element driven by said driving means moves; comparing means for comparing an output of said detecting means with a predetermined value to output an error signal; and deflecting means for deflecting the light beam signal in a subscanning direction in response to said error signal produced by said comparing means.
Claim 3
Dependent Claim
15 words
An apparatus as claimed in claim 1, wherein said correcting means comprises an electrooptical element.
Claim 4
Dependent Claim
61 words
An apparatus as claimed in claim 1, wherein said correcting means corrects the error by comparing a detection output of said detecting signal with a set signal stored in a memory and producing a correction signal representative of a sum of a difference between said detection output and said set signal and differences having been detected after the beginning of writing.
Claim 5
Dependent Claim
20 words
An apparatus as claimed in claim 3, wherein said set signal is updated every time a single copy is produced.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-10-07 | 1995-04-08 | 1995-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-07 | 1999-04-08 | 1999-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-07 | 2003-04-08 | 2003-10-08 | $7700.00 | Window Closed / Lapsed |