Electrophotography – Diagnostics – Document handling
Reexamination Certificate
2001-10-03
2003-08-05
Beatty, Robert (Department: 2852)
Electrophotography
Diagnostics
Document handling
C399S049000
Reexamination Certificate
active
06603932
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image-forming apparatus which is controlled to stop to avoid a situation where the adherence between toner of the image pattern a in the non-image area and a photoreceptor, intermediate transfer member or a second transfer roller increases, so as to keep the inside of the apparatus clean and to obtain clean images. Here, the image pattern &agr; is an image which inevitably forms when an image forming operation has stopped or an image pattern created in the non-image area which comes after the image area before the image forming operation is stopped and used for optimizing the quality of the normal image by detecting the density, position, etc. of the image.
There is a well-known image-forming apparatus which forms a toner image on a photoreceptor having charging, exposing, and reversal developing means in its periphery, transfers (i.e. first transfer) the toner image onto an intermediate transfer member, and then transfers (i.e. second transfer) the toner image from the intermediate transfer member onto transfer material, such as transfer paper or the like used as recording material. This kind of apparatus uses a two-component developer which includes toner having the same charging polarity as that of the photoreceptor so as to perform reversible deposition. In order to prevent a two-component developer carrier from adhering to the photoreceptor, the developing bias is impressed before charging is started when an image forming operation starts and then the developing bias is turned off after charging has been finished when the image forming operation stops. This causes the toner to adhere to the area located before and after the charged area on the photoreceptor in a belt-like appearance. If the adhering toner (especially, the toner that has adhered when the image forming operation stopped) remains on the photoreceptor or the intermediate transfer member, the toner adherence increases causing an insufficient cleaning, which results in poor image quality when the next image is printed. Further, if the adhering toner remains sandwiched between two members or remains receiving heat from the fixing unit, etc., the adherence between the toner and a transfer member, such as an intermediate transfer member, photoreceptor, or a transfer roller, further increases causing an insufficient cleaning, which results in poor image quality. Furthermore, if the toner in the image area remains on a photoreceptor or an intermediate transfer member when transfer material, such as transfer paper or the like, jams, the same thing can happen. Especially, if the adhering toner remains sandwiched between two members or remains receiving heat from the fixing unit, etc., the adherence between the toner and a transfer member, such as an intermediate transfer member, photoreceptor, or a transfer roller, further increases causing an insufficient cleaning, which results in poor image quality. Those cases happen frequently.
OBJECT OF THE INVENTION
The main purpose of the present invention is to provide an image-forming apparatus for forming a toner image on a photoreceptor, primarily transferring the toner image on the photoreceptor onto an intermediate transfer member and secondarily transferring the toner image from the intermediate transfer member onto transfer material, such as transfer paper or the like used as recording material, which does not have the problem described above. That is to say, the main purpose of the present invention is to provide an image-forming apparatus which does not stop, when a toner image exists in the non-image area and the toner image remains sandwiched between a photoreceptor and an intermediate transfer member or the intermediate transfer member and a second transfer member, so as to prevent the adherence between each member and the toner from increasing, thereby preventing image problems which affect the creation of the next image from occurring.
SUMMARY OF MEANS FOR ACHIEVING THE INVENTION
(1) An image-forming apparatus for forming a toner image on a photoreceptor having charging, exposing and developing means in its periphery, primarily transferring said toner image onto an intermediate transfer member, and then secondarily transferring said toner image from said intermediate transfer member onto transfer material, comprising cleaning means for removing residual toner which has adhered to the downstream-side surface of said intermediate transfer member in its rotational direction after the second transfer position, further comprising controller for controlling a first transfer voltage or current so that most of the toner image pattern a which has been formed in the non-image area on said photoreceptor is transferred onto said intermediate transfer member and stored thereon and also stopping said intermediate transfer member after the toner which adhered to said intermediate transfer member has been removed.
(2) An image-forming apparatus for forming a toner image on a photoreceptor having charging, exposing and developing means in its periphery, primarily transferring said toner image onto an intermediate transfer member, and then secondarily transferring said toner image from said intermediate transfer member onto transfer material, comprising cleaning means for removing residual toner which has adhered to the downstream-side surface of said photoreceptor in its rotational direction before the first transfer position, further comprising controller for controlling a first transfer voltage or current so that most of the toner image pattern a which has been formed in the non-image area on said photoreceptor remains on said photoreceptor and also stopping said photoreceptor after the toner which has adhered to said photoreceptor has been removed.
(3) An image-forming apparatus, having a second transfer member, for forming a toner image on a photoreceptor having charging, exposing and developing means in its periphery, primarily transferring said toner image onto an intermediate transfer member, and then secondarily transferring said toner image from said intermediate transfer member onto said transfer material, comprising controller for stopping said photoreceptor and said intermediate transfer member at a position where the toner image pattern a which has been formed in the non-image area on said photoreceptor when said apparatus was stopped is not sandwiched between the contacting parts of said photoreceptor and said intermediate transfer member.
(4) An image-forming apparatus according to means (3), comprising a roller or belt for making said second transfer member come in contact with said intermediate transfer member, further comprising controller for stopping said intermediate transfer member at a position where the toner image pattern &agr; which has been formed in the non-image area on said photoreceptor when said apparatus was stopped is not sandwiched between the contacting parts of said second transfer member and said intermediate transfer member.
(5) An image-forming apparatus according to Means (4), comprising a roller or belt for making said second transfer member come in contact with said intermediate transfer member, further comprising controller for stopping said intermediate transfer member after the toner image pattern &agr; which has been formed in the non-image area when said apparatus was stopped has passed the contacting parts of said photoreceptor and said intermediate transfer member and is located at a position before the contacting parts of said second transfer member and said intermediate transfer member.
(6) An image-forming apparatus for forming a toner image on a photoreceptor having charging, exposing and developing means in its periphery, primarily transferring said toner image onto an intermediate transfer member, and then secondarily transferring said toner image from said intermediate transfer member onto said transfer material, comprising controller for controlling a first transfer voltage or current so that most of the toner image pattern a which has been formed in the non
Katayanagi Hidetoshi
Kurosu Shigetaka
Saito Masashi
Beatty Robert
Frishauf Holtz Goodman & Chick P.C.
Konica Corporation
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