An image forming apparatus includes a reverse roller pair including a drive roller and a driven roller by which a recording medium is nipped and conveyed reversibly, a motor configured to rotate the drive roller reversibly, a conveyance roller pair, a detection unit configured to detect the recording medium conveyed by the conveyance roller pair, and a controller configured to control the motor, in a case in which the recording medium is detected by the detection unit, to cause the drive roller to rotate in a first rotation direction by a first rotation amount, thereafter to cause the drive motor to rotate in a second rotation direction by a second rotation amount. A difference between the first rotation amount and the second rotation amount is set to an integer multiple of a predetermined rotation amount of the motor, the predetermined rotation amount making the drive roller one rotation.

An image forming apparatus includes a reverse roller pair including a drive roller and a driven roller by which a recording medium is nipped and conveyed reversibly, a motor configured to rotate the drive roller reversibly, a conveyance roller pair, a detection unit configured to detect the recording medium conveyed by the conveyance roller pair, and a controller configured to control the motor, in a case in which the recording medium is detected by the detection unit, to cause the drive roller to rotate in a first rotation direction by a first rotation amount, thereafter to cause the drive motor to rotate in a second rotation direction by a second rotation amount. A difference between the first rotation amount and the second rotation amount is set to an integer multiple of a predetermined rotation amount of the motor, the predetermined rotation amount making the drive roller one rotation.

Disclosed is a corrugated paperboard box making machine which comprises a sheet feeding apparatus, a processing apparatus, a folder-gluer, a counter-ejector for stacking the box-structured corrugated paperboard sheets and separating them as a batch, a speed setting unit for setting a sheet feeding speed, and a control apparatus. The control apparatus is operable to execute a sheet feeding control processing of the sheet feeding apparatus such that a sheet feeding operation of feeding one corrugated paperboard sheet is successively repeated a number of times corresponding to the number of the given number of box-structured corrugated paperboard sheets in the batch, and a sheet feeding stop control processing of, when the sheet feeding speed is greater than an allowable speed, the sheet feeding apparatus such that the sheet feeding operation is stopped at least once after execution of the sheet feeding control processing.

Disclosed is a corrugated paperboard box making machine which comprises a sheet feeding apparatus, a processing apparatus, a folder-gluer, a counter-ejector for stacking the box-structured corrugated paperboard sheets and separating them as a batch, a speed setting unit for setting a sheet feeding speed, and a control apparatus. The control apparatus is operable to execute a sheet feeding control processing of the sheet feeding apparatus such that a sheet feeding operation of feeding one corrugated paperboard sheet is successively repeated a number of times corresponding to the number of the given number of box-structured corrugated paperboard sheets in the batch, and a sheet feeding stop control processing of, when the sheet feeding speed is greater than an allowable speed, the sheet feeding apparatus such that the sheet feeding operation is stopped at least once after execution of the sheet feeding control processing.

A postprocessing device includes a processing tray, a first transport roller, a second transport roller, a sidetrack, a sidetrack roller, and a controller. The controller shunts a preceding recording medium to the sidetrack by rotating the sidetrack roller, determines, on a basis of a length of the preceding recording medium in a transport direction, a timing to stop the rotation of the sidetrack roller such that, when the sidetrack roller is made to start rotating at a predetermined timing to start, a leading edge of a following recording medium transported by the second transport roller becomes aligned with a leading edge of the preceding recording medium, stops the rotation of the sidetrack roller at the determined timing, and transports the preceding recording medium with the following recording medium stacked thereon, to the processing tray, by rotating the second transport roller and the sidetrack roller at the reference timing to start.

A vacuum belt conveyor sequentially delivers sheet articles to a digital printer. The sheets are held in position by vacuum on the underside of the sheets through apertures in the belt and covered by the sheets. A plurality of independent plenums on the underside of the belt have chambers respectively communicating with rows of apertures extending along the belt. Vacuum is selectively applied from a manifold only to the plenum chambers that supply apertures that are covered by the sheets so that the ink from the printer will not be directed from its intended position on the sheet by vacuum from adjacent uncovered belt apertures.

A vacuum belt conveyor sequentially delivers sheet articles to a digital printer. The sheets are held in position by vacuum on the underside of the sheets through apertures in the belt and covered by the sheets. A plurality of independent plenums on the underside of the belt have chambers respectively communicating with rows of apertures extending along the belt. Vacuum is selectively applied from a manifold only to the plenum chambers that supply apertures that are covered by the sheets so that the ink from the printer will not be directed from its intended position on the sheet by vacuum from adjacent uncovered belt apertures.

A sheet feeding device includes a pickup roller, a lifting/lowering mechanism, and a driver device. The lifting/lowering mechanism includes a restricting member that releasably restricts the pickup roller from being lowered from a lifted position of the pickup roller at the lifted position. In the sheet feeding device, the driver device drives the lifting/lowering mechanism so that the pickup roller is lowered from the lifted position of the pickup roller, and a drive suspend operation is performed in which the driving of the lifting/lowering mechanism by driver device is suspended after a predetermined time during which the pickup roller does not contact a sheet loading tray or a sheet on the sheet loading tray elapses from a time point when the pickup roller is released from being restricted by the restricting member at the lifted position.

A post-processing apparatus includes a conveyance unit, a discharge port, a tray, an elevation unit, a detection unit, and a control unit. The conveyance unit conveys a print medium supplied from an image forming apparatus. The discharge port discharges the print medium conveyed by the conveyance unit. The tray is stacked with the print medium discharged from the discharge port and can be raised and lowered in a vertical direction. The elevation unit raises and lower the tray in the vertical direction. The detection unit detects a top surface of an uppermost print medium of one or more sheets of print media stacked on the tray. The control unit controls the conveyance unit and the elevation unit and hold a relative position of the top surface with respect to the discharge port if the print medium is discharged from the discharge port at a first position. The control unit causes the conveyance unit to convey the print medium at a first speed if a discharge time from a first timing indicating the timing relating to discharge of the print medium from the discharge port to a second timing indicating the timing when the print medium is detected by the detection unit is a first time and causes the conveyance unit to convey the print medium at a second speed different from the first speed if the discharge time is a second time.

A post-processing apparatus includes a conveyance unit, a discharge port, a tray, an elevation unit, a detection unit, and a control unit. The conveyance unit conveys a print medium supplied from an image forming apparatus. The discharge port discharges the print medium conveyed by the conveyance unit. The tray is stacked with the print medium discharged from the discharge port and can be raised and lowered in a vertical direction. The elevation unit raises and lower the tray in the vertical direction. The detection unit detects a top surface of an uppermost print medium of one or more sheets of print media stacked on the tray. The control unit controls the conveyance unit and the elevation unit and hold a relative position of the top surface with respect to the discharge port if the print medium is discharged from the discharge port at a first position. The control unit causes the conveyance unit to convey the print medium at a first speed if a discharge time from a first timing indicating the timing relating to discharge of the print medium from the discharge port to a second timing indicating the timing when the print medium is detected by the detection unit is a first time and causes the conveyance unit to convey the print medium at a second speed different from the first speed if the discharge time is a second time.