Abstract: There is provided an image processing device which converts multi-gradation pixels configuring a multi-gradation image of image data to be used in a color image forming apparatus, into unit dither patterns. The image forming apparatus includes photosensitive members on which developer images are formed by supplying developer to electrostatic latent images, and an exposure device which exposes the photosensitive members. The developer images on the photosensitive members are transferred to a transferred medium which is moved while contacting the photosensitive members. The image processing device includes a processing unit which converts a multi-gradation pixel of a first color into unit dither patterns, each unit dither pattern consisting of a first line extending in a predetermined direction and a second line extending in a direction intersecting with the first line when a gradation value of the multi-gradation pixel is within a predetermined range.

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 includes: an image carrier rotates in a predetermined direction; a correction image forming unit forming correction images on the image carrier in the predetermined direction; and a cleaning roller configured to clean the correction images on the image carrier. With respect to all values ranging from 1 to an arbitrary value n, a positive integer N which satisfies following expression for each of n exists: (T×N+L)/n?R/V?(T×(N+1)?L)/n, where R represents a circumferential length of the cleaning roller, L represents a length of each of the correction images in a moving direction of the image carrier, T represents a formation interval of the correction images in the moving direction of the image carrier, and V represents a ratio of a peripheral speed of the cleaning roller to a moving speed of the image carrier.

Abstract: There is provided an image forming apparatus including plural photosensitive members on which developer images are formed by supplying developer to electrostatic latent images, respectively, an exposure device which illuminates light beams onto surfaces of the photosensitive members to form the electrostatic latent images, respectively. The developer images on the respective photosensitive numbers are transferred to a transferred medium which is moved in a moving direction while contacting the respective photosensitive members. The exposure device is configured such that a. beam diameter of light beam exposing a most-upstream photosensitive member in the moving direction on a surface of the most-upstream photosensitive member is larger than a beam diameter of light beam exposing a most-downstream photosensitive member in the moving direction on a surface of the most-downstream photosensitive member.

Abstract: An image forming apparatus includes a control device executing: a holding process of holding developer attached on an image carrier at a holding member; a moving process of moving the developer from the holding member to the image carrier; and a collection process of collecting the developer attached on the image carrier into a collection member. The control device executes the moving process and the collection process after completing printing. The control device sets a first flag when predetermined time period elapses from start of the moving process and unsets the first flag at start of the printing. When the first flag is not set at a startup time, the control device executes the moving process and the collection process before the printing. When the first flag is set, the control device omits the moving process before the printing.

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 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: 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: Provided is an image forming apparatus including an image forming section forming images on image forming faces of a recording medium, a condition setting section individually setting an operating condition of the image forming section for forming the image on a first image forming face of a recording medium and another operating condition of the image forming section for forming the image on a second image forming face of the recording medium opposite to the first image forming face in the manual duplex mode, and a control section controlling the image forming section on the basis of each operating condition set by the condition setting section.

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 a controller capable of performing a printing control and a cleaning control. In the printing control, developer images carried on the image carriers are transferred toward the opposing surface or a recording sheet by applying a transfer current between each of the image carriers and the transfer device. In the cleaning control, developer collected by the cleaning rollers is transferred toward the image carriers and the transfer device and collected by the cleaning device by applying a transfer current between each of the image carriers and the transfer device and switching an electric field established between the image carrier and the corresponding cleaning roller. The controller is configured to control the transfer current such that an average absolute value of the transfer current in the cleaning control is smaller than that in the printing control.

Abstract: An image forming apparatus includes: an image carrier rotates in a predetermined direction; a correction image forming unit forming correction images on the image carrier in the predetermined direction; and a cleaning roller configured to clean the correction images on the image carrier. With respect to all values ranging from 1 to an arbitrary value n, a positive integer N which satisfies following expression for each of n exists: (T×N+L)/n?R/V?(T×(N+1)?L)/n, where R represents a circumferential length of the cleaning roller, L represents a length of each of the correction images in a moving direction of the image carrier, T represents a formation interval of the correction images in the moving direction of the image carrier, and V represents a ratio of a peripheral speed of the cleaning roller to a moving speed of the image carrier.

Abstract: An image forming apparatus includes: a first photosensitive drum for a monochrome printing mode; second and third photosensitive drums for a color printing mode; a moving unit moving a medium from the first photosensitive drum via the second photosensitive drum to the third photosensitive drum; charger devices for charging the photosensitive drums; transfer devices for transferring developer images on the photosensitive drums to the medium; and a control unit configured to control charging biases of the charger devices and transfer biases of the transfer devices. The control unit executes, in the monochrome printing mode, an energy saving control in which absolute value of charging bias applied to the charger device for the third photosensitive drum is smaller than an absolute value of a charging bias applied to the charger device corresponding to the second photosensitive drum.

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: Provided is an image forming apparatus including an image forming section forming images on image forming faces of a recording medium, a condition setting section individually setting an operating condition of the image forming section for forming the image on a first image forming face of a recording medium and another operating condition of the image forming section for forming the image on a second image forming face of the recording medium opposite to the first image forming face in the manual duplex mode, and a control section controlling the image forming section on the basis of each operating condition set by the condition setting section.

Abstract: Provided is an image forming apparatus including an image forming section forming images on image forming faces of a recording medium, a condition setting section individually setting an operating condition of the image forming section for forming the image on a first image forming face of a recording medium and another operating condition of the image forming section for forming the image on a second image forming face of the recording medium opposite to the first image forming face in the manual duplex mode, and a control section controlling the image forming section on the basis of each operating condition set by the condition setting section.

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.