Image forming apparatus with feeder control based on pixel conversion status

• US 5,455,603 A
• Filed: 04/14/1994
• Issued: 10/03/1995
• Est. Priority Date: 07/28/1989
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kuramochi, Yoshimi, Hori, Kenjiro, Takeuchi, Makoto, Inoue, Takahiro, Hashimoto, Hiroshi, Akiyama, Satoshi, Goto, Masahiro, Kato, Junichi, Noguchi, Akio, Nakahara, Takashi, Yano, Hideyuki, Tsukida, Shinichi, Hiroshima, Koichi, Suwa, Koichi, Yoshimoto, Toshio, Masuda, Shunichi
• Primary Examiner(s): Pendegrass, Joan H.
• Application Number:
  US08/227,695
• Time in Patent Office: 537 Days
• Field of Search: 355/317, 355/274, 355/277, 346/134, 346/160, 358/296, 358/300, 395/111, 347/139, 347/153
• US Class Current: 346/134
• CPC Class Codes: G06K 15/128 generating or processing printable items, e.g. characters
• CPC Class Codes: G06K 15/16 Means for paper feeding or form feeding

Abstract

An image forming apparatus comprises a data receiver for receiving encoded character or graphic information in the unit of a page from the outside; a pixel converter for converting the encoded character or graphic information into pixel information; an image forming device for forming an image on a recording medium based on the pixel information; and a feeder for feeding the recording medium to said image forming device. In the apparatus, the feeder is adapted to feed the recording medium to a predetermined position prior to the completion of pixel conversion of a page by the pixel converter.

Claims

1. An image forming apparatus comprising:

an image forming device for forming an image on a recording medium based on pixel information converted from encoded character or graphic information; and

a feeder for feeding the recording medium to said image forming device, said feeder comprising sheet feed rollers which feed, one by one, plural recording media stacked on a recording medium stacker, and registration rollers provided at the downstream side of said sheet feed rollers,

wherein said feeder is adapted to feed said recording medium to a predetermined position upstream of said registration rollers prior to a completion of the pixel information conversion of a page, and to cause said recording medium to impinge on said registration rollers and to drive said registration rollers to feed said recording medium to said image forming device after the completion of the pixel information conversion of a page.

2. An image forming apparatus according to claim 1, further comprising

a data receiver adapted to receive encoded character or graphic information in the unit of a page from the outside;

a pixel converter which converts said encoded character or graphic information into pixel information,

wherein said feeder is adapted to feed the recording medium to the predetermined position in response to the reception of encoded character or graphic information of a page by said data receiver.

3. An image forming apparatus according to claim 1, wherein said image forming device comprises a latent image forming device which forms an electrostatic latent image on a photosensitive member based on said pixel information, a developing device which develops said electrostatic latent image into a toner image, and a transfer device which transfers the toner image formed on said photosensitive member onto the recording medium.

4. An image forming apparatus according to claim 3, wherein at least one of said latent image forming device, developing device and transfer device is activated for image formation after the completion of pixel conversion of a page.

5. An image forming apparatus according to claim 3, wherein said transfer device is a pressure transfer device which presses the recording medium to the photosensitive member on which the toner image is formed, thereby transferring the toner image onto the recording medium.

6. An image forming apparatus according to claim 5, wherein said pressure transfer device is a transfer roller or a transfer belt.

7. An image forming apparatus according to claim 3, wherein said latent image forming device comprises a charger which charges the surface of the photosensitive member, and a modulated optical scanner which scans the photosensitive member with modulated light;

and

wherein the distance l₁ from the scanning position with said modulated light to the transfer device along the surface of the photosensitive member is larger than the distance l₂ from said predetermined position of the recording medium to the transfer device.

8. An image forming apparatus comprising:

a data receiver which receives encoded character or graphic information in the unit of a page from the outside;

a pixel converter which converts said encoded character or graphic information into pixel information;

a rotated photosensitive member;

a latent image forming device which forms an electrostatic latent image on said photosensitive member based on said pixel information;

a developing device which develops said electrostatic latent image into a toner image;

a transfer device which transfers said toner image, formed on said photosensitive member, onto a recording medium; and

a feeder which feeds the recording medium to said transfer device and is adapted to feed the recording medium to a predetermined position prior to the completion of pixel conversion of a page by said pixel converter,

wherein at least said transfer device is not activated from the feeding operation to the predetermined position until the completion of a pixel conversion of a page by said pixel converter.

9. An image forming apparatus according to claim 8, wherein said latent image forming device and developing device are activated after the completion of pixel conversion of a page.

10. An image forming apparatus according to claim 8, wherein said feeder and said photosensitive member are driven by a single power source.

11. An image forming apparatus according to claim 8, further comprising raster converter which converts the pixel information, converted by said pixel converter, into raster data, said raster converter being activated after pixel information of a page is obtained.

12. An image forming apparatus according to claim 8, wherein said transfer device is a pressure transfer device which presses the recording medium to the photosensitive member on which the toner image is formed, thereby transferring the toner image onto said recording medium.

13. An image forming apparatus according to claim 12, wherein said pressure transfer device is a transfer roller or a transfer belt.

14. An image forming apparatus according to claim 8, wherein said feeder comprises a sheet feeder which feed, one by one, plural recording media stacked on a recording medium stacker, and registration rollers provided at the downstream side of said sheet feeder.

15. An image forming apparatus according to claim 14, wherein said feeder is adapted to feed said recording medium by said sheet feeder to a position impinging on said registration rollers prior to the completion of the pixel conversion of a page by said pixel converter, and to drive said registration rollers to feed said recording medium to said image forming device after the completion of said pixel conversion of a page.

16. An image forming apparatus according to claim 14, wherein said feeder is adapted to feed said recording medium to a position upstream of said registration rollers prior to the completion of pixel conversion of a page by said pixel converter, and to cause said recording medium to impinge on said registration rollers and to drive said registration rollers to feed said recording medium to said image forming device after the completion of said pixel conversion of a page.

17. An image forming apparatus according to claim 14, wherein said feeder is adapted to feed said recording medium by said sheet feeder and said registration rollers to a position pinched by said registration rollers prior to the completion of pixel conversion of a page by said pixel converter, and to drive said registration rollers to feed said recording medium to said image forming device after the completion of said pixel conversion of a page.

18. An image forming apparatus comprising:

a data receiver which receives encoded character or graphic information in the unit of a page from the outside;

a pixel converter which converts said encoded character or graphic information into pixel information;

a rotated photosensitive member;

a latent image forming device which forms an electrostatic latent image on said photosensitive member based on said pixel information;

a developing device which develops said electrostatic latent image into a toner image;

a transfer device which transfers said toner image, formed on said photosensitive member, onto a recording medium; and

a feeder which feeds the recording medium to said transfer device and is adapted to feed the recording medium to a predetermined position prior to the completion of pixel conversion of a page by said pixel converter;

wherein said photosensitive member is stopped if said pixel conversion of a page is not completed within a predetermined first time from said feeding of the recording medium to the predetermined position, and the image formation on said recording medium already fed by said feeder is prohibited if the stopped state of said photosensitive member continues for a predetermined second time.

19. An image forming apparatus comprising:

a first controller including;

a data receiver which receives encoded character or graphic information in the unit of a page from the outside; and

a pixel converter which converts said encoded character or graphic information into pixel information;

a rotated photosensitive member;

a latent image forming device which forms an electrostatic latent image on said photosensitive member based on said pixel information;

a developing device which develops said electrostatic latent image into a toner image;

a transfer device which transfers said toner image, formed on said photosensitive member, onto a recording medium;

a feeder which feeds the recording medium to said transfer device; and

a second controller which controls said photosensitive member, latent image forming device, developing device, transfer device and feeder;

wherein said second controller is adapted to feed the recording medium to a predetermined position prior to the completion of the pixel conversion of a page by said pixel converter, then stops said photosensitive member if said pixel conversion of a page is not completed within a predetermined first time thereafter, and discharges the recording medium, already fed by said feeder, without image formation if the stopped state of said photosensitive member continues in excess of a predetermined second time.

20. An image forming apparatus according to claim 19, wherein said first controller is adapted to release a sheet discharge command signal for instructing the discharge of the recording medium already fed.

21. An image forming apparatus according to claim 19, wherein said second controller comprises a timer for measuring said first and second predetermined times, and is adapted to re-start the drive of said photosensitive member if said pixel conversion of a page is completed before the lapse of said second predetermined time, or to discharge the already fed recording medium if said pixel conversion of a page is not completed.

22. An image forming apparatus comprising:

a data receiver which receives encoded character or graphic information from the outside;

a pixel converter which converts said encoded character or graphic information into pixel information;

an image forming device which forms an image on a recording medium based on said pixel information;

a feeder which feeds the recording medium to said image forming device and is adapted to feed the recording medium to a predetermined position, prior to the completion of the pixel conversion of a page by said pixel converter; and

a discharge device which discharges the recording medium subjected to image formation by said image forming device, said discharge means being adapted to discharge said recording medium without image formation if said pixel conversion of a page is not completed within a predetermined time from said feeding of the recording medium to the predetermined position.

23. An image forming apparatus according to claim 22, wherein said image forming device comprises a latent image forming device which forms an electrostatic latent image on a photosensitive member based on said pixel information, a developing device which develops said electrostatic latent image into a toner image, and a transfer device which transfers the toner image formed on said photosensitive member onto the recording medium.

24. An image forming apparatus comprising:

an image forming device for forming an image on a recording medium based on pixel information converted from encoded character or graphic information; and

a feeder for feeding the recording medium to said image forming device,

wherein said feeder is adapted to feed said recording medium to a predetermined position prior to a completion of the pixel information conversion of a page, and to feed said recording medium to said image forming device after the completion of the pixel information conversion of a page, and

wherein the image formation on said recording medium is prohibited when said pixel information conversion of a page is not completed within a predetermined time from said feeding of the recording medium to the predetermined position.

25. An image forming apparatus according to claim 24, further comprising:

a sheet discharger for discharging the recording medium subjected to image formation by said image forming device,

wherein said sheet discharger is adapted to discharge said recording medium without image formation when said pixel information conversion of a page is not completed within a predetermined time from said feeding of the recording medium to the predetermined position.

26. An image forming apparatus according to claim 24, further comprising:

a data receiver adapted to receive encoded character or graphic information in the unit of a page from the outside; and

a pixel converter which converts said encoded character or graphic information into pixel information,

wherein said feeder is adapted to feed the recording medium to the predetermined position in response to the reception of encoded character or graphic information of a page by said data receiver.

27. An image forming apparatus according to claim 24, wherein said image forming device comprises a latent image forming device which forms an electrostatic latent image on a photosensitive member based on said pixel information, a developing device which develops said electrostatic latent image into a toner image, and a transfer device which transfers the toner image formed on said photosensitive member onto the recording medium.

28. An image forming apparatus according to claim 27, wherein at least one of said latent image forming device, developing device and transfer device is activated for the image forming after the completion of pixel conversion of a page.

29. An image forming apparatus according to claim 27, wherein said transfer device is a pressure transfer device which presses the recording medium to the photosensitive member on which the toner image is formed, thereby transferring the toner image onto the recording medium.

30. An image forming apparatus according to claim 29, wherein said pressure transfer device is a transfer roller or a transfer belt.

31. An image processing apparatus for sending pixel information to a printing unit adapted to feed a recording medium to a predetermined position in response to a sheet feed command signal from the image processing apparatus, comprising:

a data receiver which receives encoded character or graphic information in the unit of a page from the outside;

a pixel converter which converts said encoded character or graphic information into pixel information; and

a data sender which is adapted to send the pixel information to the printing unit,

wherein said image processing apparatus transmits the sheet feed command signal prior to the completion of the pixel conversion of a page by said pixel converter, and

wherein said apparatus transmits the sheet feed command signal to said printing unit through an exclusive line.

32. An image processing apparatus according to claim 31, wherein the printing unit comprises a photosensitive member, and

wherein said image processing apparatus includes means for outputting to the printing unit a control signal for stopping the drive of said photosensitive member unit until the completion of pixel conversion of a page by said pixel converter.

33. An image processing apparatus according to claim 32, wherein said image processing apparatus transmits the photosensitive member control signal to the printing unit through an exclusive line.

34. An image processing apparatus according to claim 32, wherein said image processing apparatus is adapted to supply the printing unit with a start command signal for instructing the start of an image forming operation and a vertical synchronization signal.

35. An image processing apparatus according to claim 34, wherein said image processing apparatus is adapted to receive from the printing unit a vertical synchronization request signal for requesting said vertical synchronization signal;

and said apparatus is further adapted, after the reception of the vertical synchronization request signal, to send the photosensitive member control signal on a same line as that for said start command signal.

36. An image processing apparatus according to claim 34, wherein said image processing apparatus is adapted, prior to the output of the start command signal, to send said sheet feed command signal on a same line as that for the vertical synchronization signal.

37. An image processing apparatus according to claim 31, further comprising the printing unit.

38. An image processing apparatus according to claim 37, wherein said printing unit comprises:

a rotatable photosensitive member;

a latent image forming device which forms an electrostatic latent image on said photosensitive member based on said pixel information;

a developing device which develops said electrostatic latent image into a toner image;

a transfer device which transfers said toner image formed on said photosensitive member onto a recording medium;

a feeder which feeds the recording medium to said transfer device; and

a controller which controls said photosensitive member, latent image forming device, developing device, transfer device and feeder.

39. An image forming apparatus comprising;

an image forming device for forming an image on a recording medium based on pixel information converted from encoded character or graphic information; and

a feeder for feeding the recording medium to said image forming device,

wherein said feeder feeds said recording medium to predetermined position prior to a completion of the pixel information conversion of a page when a sheet feed command signal sent from a pixel information source is received, and

wherein the sheet feed command signal is received through an exclusive line.

40. An image forming apparatus according to claim 39, wherein said image forming device comprises:

a rotatable photosensitive member;

a latent image forming device which forms an electrostatic latent image on said photosensitive member based on said pixel information;

a developing device which develops said electrostatic latent image into a toner image;

a transfer device which transfer said toner image formed on said photosensitive member onto a recording medium,

wherein said feeder feeds the recording medium to said transfer device; and

a controller which controls said photosensitive member, latent image forming device, developing device, transfer device and feeder.

41. A printing apparatus comprising:

means for inputting code information from an external apparatus;

means for converting the input code information into pixel information;

means for forming an image onto a sheet in accordance with the pixel information;

means for feeding a sheet to said image forming means; and

means for discriminating whether a next page of the code information is inputted,

wherein said inputting means has provision for inputting at least the next page of code information during processing of a current page and said feeding means has provision for starting feeding of the next sheet during printing of the current page when said discriminating means discriminates that input of the code information of the next page has been completed.

42. An image forming apparatus according to claim 41, wherein said image forming means comprises latent image forming means for forming a latent image on a photosensitive member by scanning a light modulated based on pixel information, developing means for developing said latent image into a toner image, and transferring means for transferring the toner image on said photosensitive member onto the sheet, and

wherein said feeding means starts to feed the next page during formation of the latent image of the current page when said discriminating means discriminates that the input of the code information of the next page has been completed.

43. An image forming apparatus according to claim 42,

wherein said feeding means stops feeding the sheet at a predetermined position, and resumes conveying the sheet to said image forming means after converting the input code information into pixel information by said converting means is completed, and

wherein drive of said photosensitive member is stopped before the converting to the pixel information is completed even if a predetermined time has elapsed after the sheet is stopped at the predetermined position.

44. An image forming apparatus according to claim 43, further comprising means for indicating the drive of the stopped photosensitive member.

45. An image forming apparatus according to claim 42, further comprising sheet discharging means for discharging the sheet subjected to image formation by said image forming means,

wherein said sheet discharging means is adapted to discharge said sheet without image formation when said conversion of the next page is not completed within a predetermined time from a start of said feeding of the sheet from the predetermined position.

46. An image forming apparatus according to claim 42, wherein said transferring means is one of a transfer roller and a transfer belt.

47. An image forming apparatus according to claim 42,

wherein a distance l₁ from the scanning position with said modulated light to the transfer position along the surface of the photosensitive member is larger than a distance l₂ from said predetermined position of the recording medium to the transferring means.

48. An image forming apparatus according to claim 42, wherein at least one of said latent image forming means, developing means and transferring means is activated for the image forming after the completion of pixel conversion of a page.

49. An image forming apparatus according to claim 41,

wherein said feeding means stops feeding the sheet at a predetermined position, and resumes conveying the sheet to said image forming means after converting the input information into pixel information by said converting means is completed.

50. An image forming apparatus according to claim 49, wherein said image forming means forms an image on the sheet by electrophotographic recording, and said apparatus is capable of starting the feeding of the next sheet even during the formation of the latent image of the current page when said discriminating means discriminates that the input of the code information has been completed.