Abstract: An apparatus for forming a multi-color is disclosed which includes a controller that performs an anti reverse-transfer control such that a surface potential of a previously-formed separated-developer-image subset of a plurality of single-color separated-developer-images which has been previously transferred onto an image transferred medium is reduced, prior to a subsequent transfer in which a remainder of the plurality of separated-developer-images is transferred onto the image transferred medium after a previous transfer of the previously-formed separated developer-image subset onto the image transferred medium, to thereby prevent a reverse transfer of a part of a developer material on the image transferred medium from the image transferred medium onto a photoconductor at the subsequent transfer.

Abstract: An image forming device in a continuous mode forms monochrome images on a plurality of recording media in succession. A transfer member is disposed in confrontation with a plurality of photosensitive members. In the continuous mode, a control unit controls a reverse-transfer unit to perform a reverse-transfer operation on at least one of a plurality of collecting members such that the excrescences are transferred from the at least one of the photosensitive members onto the transfer member in a medium interval. A switching unit sets a contact state to a first contact state during the reverse-transfer operation in the continuous mode such that one of the developing rollers for black contacts one of the photosensitive members for black and that remaining ones of the developing rollers are separated from remaining ones of the photosensitive members.

Abstract: In an image forming apparatus, a first photoconductor drum for use in at least in a monochrome printing mode is located upstream, in a direction of transport of a medium, of a plurality of second photoconductor drums for use in a color printing mode. A transfer bias for each of transfer members is regulated in such a manner that a transfer bias applied in the monochrome printing mode between a second photoconductor drum located adjacently downstream of the first photoconductor drum and the corresponding transfer member is larger than that applied in the color printing mode. A developing bias for each of the development rollers is regulated in such a manner that an absolute value of a developing bias voltage applied to a development roller corresponding to the first photoconductor drum in the monochrome printing mode is smaller than that applied in the color printing mode.

Abstract: An image forming apparatus including an image carrier; a transfer member, which is provided in a face-to-face relation to the image carrier and to which a transfer bias is applied; a first sensor that measures a resistance value of a section between the image carrier and the transfer member; and transfer bias controlling means. The transfer bias controlling means controls the transfer bias, which is applied to the transfer member based on a first resistance value measured by the first sensor before a recording sheet enters a nip between the image carrier and the transfer member and also based on a second resistance value measured by the first sensor when the recording sheet has entered the nip between the image carrier and the transfer member.

Abstract: An image forming apparatus includes photosensitive members which each carry a developer image, transfer members which attract the developer images from the photosensitive members; a sheet housing unit which houses recording sheets; a recording sheet feeding mechanism, which feeds out a recording sheet from within the sheet housing unit and a guide member, which guides the sheet fed out by the recording sheet feeding mechanism towards a position between the photosensitive member and the transfer member. The guide member has a conductive member, which is brought into abutment with a leading end portion of a recording sheet while the recording sheet still remains in the sheet housing unit, and which is grounded electrically and insulation members which the recording sheet is brought into abutment when the leading end portion of the sheet reaches the transfer member.

Abstract: An Image Forming Apparatus has a controller for controlling a second bias, which is applied to a cleaning member, based on a value of electric current measured by a current sensor. The controller controls the second bias on based on the value of the current measured when a predetermined measurement range of a transport belt is in contact with the cleaning member. The measurement range is a range in which conditions, under which the first bias and the second bias are applied, are identical.

Abstract: A color image forming apparatus is described. The color image forming apparatus may includes: a belt that travels in a prescribed direction; a plurality of image carriers arranged in parallel in the prescribed direction, and opposed to the belt and carrying developing agent images of different colors respectively; a backup roller arranged in opposed relation to the belt; a cleaning roller arranged in opposed relation to the backup roller with the belt sandwiched therebetween, and adsorbing an adherent to the belt by a potential difference produced between the backup roller and the cleaning roller; and a discharge member opposed to the belt between a position more downstream in the prescribed direction than a position where the cleaning roller is opposed to the belt and a position more upstream in the prescribed direction than a position where the image carrier arranged on the most upstream side in the prescribed direction is opposed to the belt, for discharging the belt.

Abstract: Whether or not a density of black is a predetermined value or more is judged, and when it is judged to be the predetermined value or more, a resolution characteristic is changed to an improved resolution characteristic compared to the resolution characteristic used in a case in which a judgment result shows a value under the predetermined value. When the density of black is deeper, the resolution characteristic is improved, and therefore black is prevented from becoming in a so-called void state. Accordingly, the color close to black such as four-color black can be stably and excellently formed. In addition, when the density of black is the value under the predetermined value, the resolution characteristic lower than this value is used, and therefore dots can be stably formed and an excellent gradation property can be achieved.

Abstract: An image forming apparatus is provided which includes a switching mechanism which selectively shifts developing rollers among an all-color non-contact state in which all photosensitive members are kept apart from the corresponding developing rollers, a black contact state in which only the photosensitive member for black is kept in contact with the corresponding developing roller, and an all-color contact state in which all the photosensitive members are kept in contact with the corresponding developing rollers, and a control section which, when an operation mode of the apparatus is shifted from a color mode to a monochrome mode, causes the switching mechanism to shift the developing rollers from the all-color contact state to the all-color non-contact state to perform a transferring process to once transfer developing agents from recovery members onto the corresponding photosensitive members and further transfer the developing agents from the photosensitive members onto a transfer belt.

Abstract: An electrophotographic image forming apparatus is provided. The image forming apparatus includes an image forming unit configured to form an image on a recording medium; a fixing unit configured to fix the image onto the recording medium by applying heat and pressure; a re-transport unit configured to re-transport the recording medium which has passed through the fixing unit, to the image forming unit along a re-transport path; a cooling unit provided between the fixing unit and the image forming unit along the re-transport path and configured to cool the recording medium transported by the re-transport unit; a parameter signal output unit configured to output a signal corresponding to a parameter for controlling the cooling unit; and a controller configured to control the cooling unit according to the signal output from the parameter signal output unit.

Abstract: An image forming apparatus includes an image formation unit such as a process section for forming an image on a recording sheet. The apparatus may include a fixing unit for fixing the image formed by the image formation unit on the recording sheet, a reversible roller configured to receive the sheet from the fixing unit along a sheet transport path and reverse a transport direction of the sheet, and an air blower, positioned between the fixing unit and the reversible roller along the sheet transport path, configured to blow air in a sheet feeding direction onto the recording sheet on which the image is fixed by the fixing unit.

Abstract: An apparatus for forming a multi-color is disclosed which includes a controller that performs an anti reverse-transfer control such that a surface potential of a previously-formed separated-developer-image subset of a plurality of single-color separated-developer-images which has been previously transferred onto an image transferred medium is reduced, prior to a subsequent transfer in which a remainder of the plurality of separated-developer-images is transferred onto the image transferred medium after a previous transfer of the previously-formed separated developer-image subset onto the image transferred medium, to thereby prevent a reverse transfer of a part of a developer material on the image transferred medium from the image transferred medium onto a photoconductor at the subsequent transfer.

Abstract: The pressure between a developing roller and a photosensitive drum is set to 0.24 MPa. Because the pressure is smaller than 0.31 MPa, if the potential difference ?V between the non-image forming part on the photosensitive drum and the electrically-charged polymer toner on the surface of the developing roller is at the preset proper voltage (300 volts), pressure fogging will be prevented. Because the pressure is 0.24 MPa or less, even if the potential difference varies within the range of 200 volts to 400 volts that occurs in practice, pressure fogging will be prevented. By resetting the pressure to 0.22 MPa, even if the potential difference ?V varies in a wider voltage range of 100 to 400 volts, pressure fogging will be prevented. In this way, by setting the pressure between the developing roller and the photosensitive drum appropriately, pressure fogging can be prevented even when using the opposite-direction developing method and polymer toner.

Abstract: An image forming apparatus may be provided with a belt configured to move in the predetermined direction and face a photoreceptor, a charge removal member, and a conductive member. The charge removal member may be configured to remove charge of the belt. The conductive member may be located at the downstream side of the charge removal member in the predetermined direction. The conductive member may include a surface facing the belt.

Abstract: An image-forming device includes 1st to Nth image bearing members, 1st to Nth developing units provided in one-to-one correspondence with the 1st to Nth image bearing members, and a transfer unit. N is an integer number equal to or greater than two. The 1st to Nth image members have 1st to Nth surfaces respectively. The 1st to Nth electrostatic latent images are formable on the 1st to Nth surface respectively. The 1st to Nth developing units have 1st to Nth monochromatic developers respectively. The 1st monochromatic developer is of monochromatic black and has a toner particle substantially spherical in shape. The 1st to Nth developing units develop the 1st to Nth electrostatic latent images with the 1st to Nth monochromatic developers respectively in order to form 1st to Nth developer images respectively. The transfer unit transfers sequentially the 1st to Nth developer images to a recipient in a superimposed manner in order of the 1st to Nth developer image.

Abstract: An image forming apparatus is provided which includes a switching mechanism which selectively shifts developing rollers among an all-color non-contact state in which all photosensitive members are kept apart from the corresponding developing rollers, a black contact state in which only the photosensitive member for black is kept in contact with the corresponding developing roller, and an all-color contact state in which all the photosensitive members are kept in contact with the corresponding developing rollers, and a control section which, when an operation mode of the apparatus is shifted from a color mode to a monochrome mode, causes the switching mechanism to shift the developing rollers from the all-color contact state to the all-color non-contact state to perform a transferring process to once transfer developing agents from recovery members onto the corresponding photosensitive members and further transfer the developing agents from the photosensitive members onto a transfer belt.