Abstract: An image forming apparatus for which a control method is performed includes a recording unit, a conveying device conveying a recording medium to the recording unit, a feeding device supplying the recording medium to the conveying device, a recording medium conveying pathway along which the recording medium travels, and a control device controlling the conveying device and the feeding device. A first partial length of the recording medium conveying pathway extending from the feeding device to the recording unit is shorter than a conveyance direction length of a maximum usable size recording medium. When the leading end of the recording medium is located between the conveying device and the recording unit after the conveying device is driven to convey the recording medium, the control device switches the feeding device from a driven state to a non-driven state to move the feeding device by the recording medium.

Abstract: A drive transmission device includes a gear train and a movable gear locking device. The gear train transmits rotational drive to a drive target, and includes a first gear train forming a first transmission path for transmitting the drive to the target, a second gear train forming a second transmission path for transmitting the drive to the target as drive opposite in rotation direction to the drive transmitted by the first gear train, and a movable gear movable between a first drive transmission position whereat the movable gear forms a part of the first gear train to transmit the drive to the target and a second drive transmission position whereat the movable gear forms a part of the second gear train to transmit the drive to the target. The movable gear locking device locks the movable gear at an idle position.

Abstract: A sheet feeding device includes a sheet feed cassette, a bottom plate and an end wall mechanism. When the number of recording media sheets decreases, the bottom plate hinged at a trailing edge thereof rises about the hinged end to keep the top sheet of the recording media sheets in contact with a sheet feed roller. The end wall mechanism includes a first urging member, a first pressing member, a support member, and a second pressing member, and aligns and presses the trailing edge of the recording medium. The first pressing member urged by the first urging member and supported by the support member presses the trailing edge of the recording medium. The second pressing member urged by the second urging member moves down due to the weight of the recording medium on the second pressing member and moves up when the number of the recording media sheets decreases.

Abstract: A conveyer includes a first rotating body; a second rotating body pair; and an intermediate rotating body arranged between the first rotating body and the second rotating body pair. A curl of the recording medium is corrected by winding and bending the recording medium around and with the intermediate rotating body at a bent angle formed by a tangent line shared by the intermediate rotating body and the first rotating body, and a line on which such a tangent line of the intermediate rotating body is connected to a nip point of the second rotating body pair. The intermediate rotating body includes an escape mechanism that is capable of causing the intermediate rotating body to escape in a direction to increase the bent angle depending on the width of the recording medium.

Abstract: A guide device for guiding a recording medium discharged from a fixing device includes a first conveyance wall plate and at least one rib assembly mounted on the first conveyance wall plate. The at least one rib assembly includes a plurality of primary ribs contacting the first conveyance wall plate, each having a first thickness in a recording medium conveyance direction; and a plurality of secondary ribs mounted on selected ones of the plurality of primary ribs. Each secondary rib includes a bottom contacting the primary rib and having a second thickness in the recording medium conveyance direction that is smaller than the first thickness of the primary rib; and a top contacting the recording medium and having a third thickness in the recording medium conveyance direction that is smaller than the second thickness of the bottom of the secondary rib.

Abstract: The sheet thickness detector includes a fixed member, a displacement roller disposed opposite the fixed member and movable in such a linear direction as to be contacted with or separated from the fixed member when the sheet passes through a nip therebetween, bearings rotatably supporting a shaft of the displacement roller, a displacement member movable in the linear direction in conjunction with the displacement roller and integrated with at least one of the bearings, and a displacement sensor operatively connected to the displacement member and detecting displacement of the displacement member. The thickness of the sheet passing through the nip is determined based on the amount of displacement of the displacement member.

Abstract: In a recording medium conveyer, a driver drives a feeding member and a conveying member provided downstream from the feeding member in a recording medium conveyance direction independently. A controller stops driving the feeding member when a first time period elapses after a recording medium reaches the conveying member. When a selector judges that the thickness of the recording medium identifies the recording medium as thin paper, the controller does not drive the feeding member after the controller starts driving the conveying member, and when the selector judges that the recording medium has a thickness greater than a thickness of the recording medium that identifies the recording medium as thin paper, the controller restarts driving the feeding member no later than when the controller starts driving the conveying member.

Abstract: A sheet discharge roller has a contact portion in contact with a feed roller and a noncontact portion not in contact with the feed roller. The sheet discharge roller includes a kick-out unit having a projected portion and a recess portion on one end of the noncontact portion in the circumferential direction. A reverse roller also has a contact portion in contact with the feed roller and a noncontact portion not in contact with the feed roller. The reverse roller includes a large-diameter portion on its one end in a direction opposite to a direction of the kick-out unit. The large-diameter portion has a diameter larger than a diameter of the contact portion.

Abstract: An image forming device is disclosed. The device includes a toner-image forming unit which forms a toner image; a transfer unit; a fixing unit; a paper-output unit; a drive unit; a first drive-power transmission gear; a second drive-power transmission gear; a gear housing; a first positioning unit which positions the fixing unit relative to a device body; and a second positioning unit. The second positioning unit positions the paper-output unit relative to the device body in the direction of a gap between the first drive-power transmission gear and the second drive-power transmission gear by engaging the gear housing with the device body.

Abstract: A sheet feeding device includes a sheet feeding member, a friction separation member, a retaining member, a downstream guiding member, and a biasing member. The downstream guiding member is arranged downstream of a sheet conveyance direction than the friction separation member such that its guide surface is inclined at a predetermined angle to a front surface of the friction separation member towards the sheet feeding member. A line joining an apex of a sheet guiding member arranged upstream of the sheet conveyance direction than the friction separation member and an apex of the downstream guiding unit is positioned towards the sheet feeding member than a contact portion of the sheet feeding member and the friction separation member.

Abstract: A sheet feeding device includes a feeding device and a detector. The feeding device is configured to feed a sheet to a destination. The detector is configured to detect the sheet at the destination. If the detector does not detect the sheet within a predetermined time after the start of preparation for a feeding operation by the feeding device, it is determined that the sheet is misfed. Further, the start of the feeding operation of a sheet is changed in accordance with the result of detection by the detector of the presence or absence of a sheet standing by at the destination.

Abstract: An image forming apparatus enables a high-quality double-side printing of a transfer medium by one-pass method using a simple structure. A latent image is formed and developed on an image carrier (drum) in a process cartridge. A resultant toner image is transferred by a first transfer unit (roller) onto either an upper surface of the transfer medium or a first intermediate transfer body (roller) in a first transfer area. The toner image on the first intermediate transfer body is transferred onto a back surface of the transfer medium in a fourth transfer area via a second intermediate transfer body (belt) and a third intermediate transfer body (roller). The fourth transfer area is located downstream of the first transfer area along a transport path of the transfer medium.

Abstract: An open/close mechanism can be used for paper trays of an image forming apparatus. The open/close mechanism includes a plate member provided on a side of a housing of the image forming apparatus and configured to pivot upon an axis between an open position and a close position, and a box member that is arranged in the housing beneath the plate member and that can be drawn out of the housing from the side. The open/close mechanism includes also includes a restricting unit that is coupled to the plate member and that abuts against the box member when the box member is set in the housing and when the plate member is in the open position thereby restricting detachment of the box member from the housing.

Abstract: An open/close mechanism can be used for paper trays of an image forming apparatus. The open/close mechanism includes a plate member provided on a side of a housing of the image forming apparatus and configured to pivot upon an axis between an open position and a close position, and a box member that is arranged in the housing beneath the plate member and that can be drawn out of the housing from the side. The open/close mechanism includes also includes a restricting unit that is coupled to the plate member and that abuts against the box member when the box member is set in the housing and when the plate member is in the open position thereby restricting detachment of the box member from the housing.

Abstract: An image forming apparatus, forming a color image by successively superposing color images, formed on image carriers of corresponding image forming parts arranged along a rotational direction of an endless moving member, onto the endless moving member or a recording medium conveyed thereby, includes a first part causing a color registration pattern to be created on the endless moving member or the recording medium; a second part obtaining a color registration pattern signal by detecting the color registration pattern; a third part changing image formation timing in the image forming parts based on the color registration pattern signal; and a fourth part causing the endless moving member to rotate in forward and reverse directions after the creation of the color registration pattern. The second part obtains the color registration pattern signal by detecting the color registration pattern during each of the forward and reverse rotations of the endless moving member.

Abstract: A sheet discharge device discharges a sheet to a sheet discharge tray. The sheet discharge device includes a rotary shaft, two inside drive rollers, two outside drive rollers, two inside driven rollers, two outside driven rollers, two end retainers, and two inside retainers. The drive rollers are rotatably attached to the rotary shaft. Each of the driven rollers opposes a corresponding one of the drive rollers to be driven by the drive roller. The end retainers and the inside retainers rotatably extend from the rotary shaft across a common tangent of the driven rollers and the drive rollers. The end retainers are longer than the inside rollers and constructed so as to rest on the stacked sheets.

Abstract: In a color printer in which a drive force of a fixed gear that rotates not in both a forward direction and a reverse direction but in either one direction only is transmitted to a discharging unit, a swing gear is attached to a branch guide via a switching link and a transmission link as a link mechanism. When a solenoid mechanism starts driving, the transmission link rotates. In accordance with the rotation of the transmission link, the switching link rotates, so that a switching among a discharge conveying path, a duplex-printing conveying path, and a switchback conveying path by the branch guide and a switching of a rotating direction of a transmission gear can be simultaneously performed.

Abstract: An image forming apparatus for which a control method is performed includes a recording unit, a conveying device conveying a recording medium to the recording unit, a feeding device supplying the recording medium to the conveying device, a recording medium conveying pathway along which the recording medium travels, and a control device controlling the conveying device and the feeding device. A first partial length of the recording medium conveying pathway extending from the feeding device to the recording unit is shorter than a conveyance direction length of a maximum usable size recording medium. When the leading end of the recording medium is located between the conveying device and the recording unit after the conveying device is driven to convey the recording medium, the control device switches the feeding device from a driven state to a non-driven state to move the feeding device by the recording medium.

Abstract: A sheet inverting device includes a loop pathway including an entrance slot to which a recording medium is conveyed and an exit slot from which the recording medium is conveyed, the loop pathway forming a loop shape to convey the recording medium therethrough in a forward direction defined by a sheet conveyance direction in which the recording medium is conveyed from the entrance slot travels, and a redirectable sheet conveyance member to convey the recording medium traveling through the loop pathway in the forward direction and a reverse direction that is the reverse of the forward direction. The exit slot is configured to convey the recording medium that is conveyed by the redirectable sheet conveyance member in the reverse direction outside the sheet inverting device therethrough.

Abstract: An image forming apparatus includes an image forming unit forming an image on a sheet transported along a transport path in a printing operation; a sheet stacking unit in which the sheet ejected at the end of the transport path is stacked; a sheet detecting unit detecting the presence or absence of the sheet in the transport path; a counting unit counting number-of-sheet data of the sheet detected by the sheet detecting unit; and a control unit controlling the printing operation in accordance with a first print request from a print instructing unit for a print job and based on a count value obtained by the counting unit. The control unit clears the count value in the absence of a next print request from the print instructing unit within a predetermined time after completion of the printing operation.