Image forming apparatus including first and second cleaning members
| Title: | Image forming apparatus including first and second cleaning members |
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| Patent Number: | 7,620,339 |
| Publication Date: | November 17, 2009 |
| Appl. No: | 11/466700 |
| Application Filed: | August 23, 2006 |
| Abstract: | An image forming apparatus includes a first image forming station including an image bearing member, developing means for developing an electrostatic image formed on the image bearing member with toner, wherein the toner remaining on the image bearing member after a developed image is transferred, is collected by the developing means; a transfer rotatable member; a first cleaning member for removing toner from the transfer rotatable member; a second image forming station including an image bearing member, developing means for developing an electrostatic image formed on the image bearing member with toner, a second cleaning member for removing the toner remaining on the image bearing member after a developed image is transferred, wherein the second image forming station is disposed downstream of the first image forming station and upstream of the second cleaning member with respect to a peripheral moving direction of rotation of the transfer rotatable member; and collection control means for a control operation to collect, by the second cleaning member of the second image forming station, the toner discharged to the transfer rotatable member from the first image forming station during a non-image-formation period. |
| Inventors: | Kubo, Norihiko (Toride, JP) |
| Assignees: | Canon Kabushiki Kaisha (Tokyo, JP) |
| Claim: | 1. An image forming apparatus comprising: a first image forming station including a first image bearing member and developing means for developing an electrostatic image formed on said first image bearing member with toner, wherein the toner remaining on said first image bearing member after a developed image is transferred, is collected by said developing means; a transfer rotatable member; a first cleaning member for removing toner from said transfer rotatable member; a second image forming station including a second image bearing member and developing means for developing an electrostatic image formed on said second image bearing member with toner, a second cleaning member for removing the toner remaining on said second image bearing member after a developed image is transferred, wherein said second image forming station is disposed downstream of said first image forming station and upstream of said first cleaning member with respect to a peripheral moving direction of rotation of said transfer rotatable member; and collection control means for performing a control operation to collect, by said second cleaning member of said second image forming station, the toner discharged to said transfer rotatable member from said first image forming station during a non-image-formation period. |
| Claim: | 2. An apparatus according to claim 1 , further comprising a plurality of image forming stations each including an image bearing member, developing means for developing an electrostatic image formed on said image bearing member with toner, wherein the toner remaining on said image bearing member after a developed image is transferred is collected by said developing means, and wherein said second image forming station is disposed at the most downstream position with respect to a peripheral moving direction of rotation of said transfer rotatable member. |
| Claim: | 3. An apparatus according to claim 1 , wherein said first image forming station further includes an auxiliary charging member for being supplied with a voltage having a polarity which is the same as a regular toner polarity to electrically charge the toner remaining on said first image bearing member after the developed image is transferred, and said collection control means discharges the toner stagnating in said auxiliary charging member from said first image bearing member to said transfer rotatable member and the toner is collected by said second cleaning member. |
| Claim: | 4. An apparatus according to claim 1 , wherein said second image forming station forms a black toner image. |
| Claim: | 5. An apparatus according to claim 1 , wherein said second image bearing member in said second image forming station includes a surface layer of amorphous silicon. |
| Claim: | 6. An apparatus according to claim 1 , wherein said transfer rotatable member is an intermediary transfer member onto which the toner image is transferred from said image forming stations, and wherein said first image forming station and said second image forming station each include a primary transfer member for transferring the toner image from the associated image bearing member onto said transfer rotatable transfer member, and a secondary transfer member for transferring the toner image from said transfer rotatable member onto the recording material. |
| Claim: | 7. An apparatus according to claim 6 , wherein the toner discharged onto said transfer rotatable member is collected by said second image bearing member of second image forming station by application of a voltage having a polarity opposite the regular toner polarity to said primary transferring means of said second image forming station. |
| Claim: | 8. An apparatus according to claim 6 , wherein the toner discharged onto said transfer rotatable member is collected by said second image bearing member of said second image forming station by application of a voltage having a polarity opposite the regular toner polarity to said primary transferring member of said second image forming station and wherein the voltage applied to said primary transferring member is larger than a voltage applied thereto during an image forming operation period in absolute value. |
| Claim: | 9. An apparatus according to claim 1 , further comprising collection selecting means for selecting whether to effect the collection by said collection control means. |
| Claim: | 10. An apparatus according to claim 9 , further comprising image density calculating means for detecting image densities of output images and integrating the image densities and calculating an average image print ratio for each of predetermined numbers of output images, wherein said collection selecting means effects the toner collection when the average image print ratio β 2 calculated by said image density calculating means in said second image forming station is smaller than a predetermined value β 1 in the predetermined number of the output images. |
| Claim: | 11. An image forming apparatus comprising: a first image forming station including a first image bearing member and developing means for developing an electrostatic image formed on said first image bearing member with toner, wherein the toner remaining on said first image bearing member after a developed image is transferred, is collected by said developing means; an intermediary transfer member for carrying a toner image transferred from said first image bearing member; a second transfer member for transferring the toner image from said intermediary transfer member onto a recording material; and a second image forming station including a second image bearing member and developing means for developing an electrostatic image formed on said second image bearing member, and a cleaning member for removing the toner remaining on said second image bearing member, wherein said second image forming station is disposed downstream of said first image forming station and upstream of said second transfer member with respect to a peripheral moving direction of rotation of said intermediary transfer member, wherein said apparatus is operable in a collection mode in which the toner discharged from said first image forming station to said intermediary transfer member during a non-image-formation period is collected by said cleaning member of said second image forming station. |
| Claim: | 12. An apparatus according to claim 11 , further comprising a plurality of image forming stations each including an image bearing member, developing means for developing an electrostatic image formed on said image bearing member with toner, wherein the toner remaining on said image bearing member after a developed image is transferred is collected by said developing means, and wherein said second image forming station is disposed at the most downstream position with respect to a peripheral moving direction of rotation of said intermediary transfer member. |
| Claim: | 13. An apparatus according to claim 11 , wherein said first image forming station further includes an auxiliary charging member for being supplied with a voltage having a polarity which is the same as a regular toner polarity to electrically charge the toner remaining on said first image bearing member after the developed image is transferred, and in the collection mode, the toner stagnating in said auxiliary charging member is discharged from said first image bearing member to said intermediary transfer member and the toner is collected by said cleaning member. |
| Claim: | 14. An apparatus according to claim 11 , wherein said second image forming station forms a black toner image. |
| Claim: | 15. An apparatus according to claim 11 , wherein said second image bearing member in said second image forming station includes a surface layer of amorphous silicon. |
| Claim: | 16. An apparatus according to claim 11 , wherein in the collection of the toner from said intermediary transfer member to said second image bearing member of said second image forming station, a voltage having a polarity opposite the regular toner polarity is applied to said intermediary transfer member which transfers the toner image from said intermediary transfer member onto said second image bearing member of said second image forming station. |
| Claim: | 17. An apparatus according to claim 11 , wherein in the collection of the toner from said intermediary transfer member to said second image bearing member of the second image forming station, a voltage having a polarity opposite the regular toner polarity is applied to said intermediary transfer member which transfers the toner image from said intermediary transfer member onto said second image bearing member of said second image forming station and wherein the voltage is larger than a voltage applied thereto during an image forming operation period in absolute value. |
| Claim: | 18. An apparatus according to claim 11 , further comprising collection selecting means for selecting whether to effect the collection by said collection control means. |
| Claim: | 19. An apparatus according to claim 18 , further comprising image density calculating means for detecting image densities of output images and integrating the image densities and calculating an average image print ratio for each of predetermined numbers of output images, wherein collection selecting means effects the toner collection when the average image print ratio β 2 calculated by said image density calculating means in said second image forming station is smaller than a predetermined value β 1 in the predetermined number of the output images. |
| Current U.S. Class: | 399/71 |
| Patent References Cited: | 6885473 April 2005 Tsuruya 6950620 September 2005 Yoshikawa et al. 7177569 February 2007 Kamimura 7206523 April 2007 Watanabe et al. 7239827 July 2007 Furukawa 2003/0049048 March 2003 Yoshikawa et al. 2007/0127944 June 2007 Mochizuki 2008/0069590 March 2008 Shigehiro 05053414 March 1993 2001-188393 July 2001 2003-156982 May 2003 2003-173062 June 2003 2003173062 June 2003 2004-117599 April 2004 |
| Primary Examiner: | Beatty, Robert |
| Attorney, Agent or Firm: | Fitzpatrick, Cella, Harper & Scinto |
| Accession Number: | edspgr.07620339 |
| Database: | USPTO Patent Grants |
| Language: | English |
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