A device for braking and positioning a print sheet in a processing machine, wherein, along a feeding direction for the print sheet, at least one mechanism exerts a braking force onto the print sheet, to position the print sheet in connection with an operation of a downstream-arranged processing station. The device includes at least a first mechanism operative to release pneumatic, braking-force triggering pulses that act upon the print sheet. At least a second mechanism is operative to generate at last one frictional force that acts upon the print sheet, wherein with aid of at least one of the first mechanism and the second mechanism, intermittent, uniform or oscillating braking forces are generated that act upon the print sheet. A control unit controls the braking forces based on at least one of changeable control profiles resulting from queried operating parameters and stored control profiles.

A method for operating a device that applies a force to a print sheet during a folding operation, wherein the print sheet is in a specified starting position prior to the folding operation. Braking-force triggering pulses are directed toward the print sheet to counter the acceleration of the print sheet in the starting phase of the folding operation and/or to counter fluttering movements that occur during the intake of the print sheet. The pulses exert an intermittent, uniform or oscillating force onto at least a section of the print sheet. The pulses are controlled by a control unit which operates based on control profiles resulting from queried operating parameters and/or based on stored control profiles.

A method for operating a device that applies a force to a print sheet during a folding operation, wherein the print sheet is in a specified starting position prior to the folding operation. Braking-force triggering pulses are directed toward the print sheet to counter the acceleration of the print sheet in the starting phase of the folding operation and/or to counter fluttering movements that occur during the intake of the print sheet. The pulses exert an intermittent, uniform or oscillating force onto at least a section of the print sheet. The pulses are controlled by a control unit which operates based on control profiles resulting from queried operating parameters and/or based on stored control profiles.

A sheet conveying apparatus including: a locking member having an abutment surface abutting a sheet to correct skew feed of the sheet; a holding member configured to hold the locking member to rotate from a waiting position when the locking member is pushed by the sheet; a roller pair configured to nip the sheet abutting the abutment surface; a first urging portion configured to urge the holding member to the waiting position; a movable support portion configured to support the locking member in a manner that the locking member is located a retracted position where the locking member contacts a surface of the sheet and allows the sheet to pass; and a second urging portion configured to urge the locking member to a position where the abutment surface abuts a succeeding sheet.

A sheet conveying apparatus including: a locking member having an abutment surface abutting a sheet to correct skew feed of the sheet; a holding member configured to hold the locking member to rotate from a waiting position when the locking member is pushed by the sheet; a roller pair configured to nip the sheet abutting the abutment surface; a first urging portion configured to urge the holding member to the waiting position; a movable support portion configured to support the locking member in a manner that the locking member is located a retracted position where the locking member contacts a surface of the sheet and allows the sheet to pass; and a second urging portion configured to urge the locking member to a position where the abutment surface abuts a succeeding sheet.

A printing apparatus comprises a conveyance control unit which controls conveyance of printing sheets so that a trailing edge of a preceding sheet as a printing sheet precedingly fed from the stacking unit and a leading edge of a succeeding sheet as a printing sheet succeedingly fed from the stacking unit overlap each other; and a skew correction unit which performs skew correction of the succeeding sheet while the succeeding sheet overlaps the preceding sheet by the conveyance control unit. The skew correction unit makes the leading edge of the succeeding sheet abut against the conveyance roller during a time from an end of a last line feed operation by the conveyance roller for printing on the preceding sheet by the printing unit to start of a next conveyance operation.

An image forming apparatus includes a pair of registration rollers, a pair of intermediate rollers, a registration sensor, and a control section that performs rotation control on the pair of registration rollers and the pair of intermediate rollers. The control section changes a starting timing of slowdown control according to a time when the registration sensor detects arrival of recording paper. The control section changes a period of time from completion of the slowdown control to start of increasing the rotational speed of the pair of registration rollers and the rotational speed of the pair of intermediate rollers from a lower speed limit to a steady state speed according to the change of the starting timing of the slowdown control.

An image forming apparatus includes a pair of registration rollers, a pair of intermediate rollers, a registration sensor, and a control section that performs rotation control on the pair of registration rollers and the pair of intermediate rollers. The control section changes a starting timing of slowdown control according to a time when the registration sensor detects arrival of recording paper. The control section changes a period of time from completion of the slowdown control to start of increasing the rotational speed of the pair of registration rollers and the rotational speed of the pair of intermediate rollers from a lower speed limit to a steady state speed according to the change of the starting timing of the slowdown control.

An image forming apparatus includes a conveying guide and a sheet member. The conveying guide is provided in a joining section and guides a sheet to a conveying roller pair along a main conveying path. The sheet member is provided in the joining section and configured to form a lower conveying path with the conveying guide and to guide the sheet from an upper conveying path toward the main conveying path. The conveying guide has a convex guide part and planer guide parts. The convex guide is provided at a center portion and projects toward the sheet member. The planer guide parts are provided on both sides of the convex guide part. A first gap formed between the convex guide part and the sheet member is narrower than a second gap formed between the planer guide part and the sheet member.

An image forming apparatus includes a conveying guide and a sheet member. The conveying guide is provided in a joining section and guides a sheet to a conveying roller pair along a main conveying path. The sheet member is provided in the joining section and configured to form a lower conveying path with the conveying guide and to guide the sheet from an upper conveying path toward the main conveying path. The conveying guide has a convex guide part and planer guide parts. The convex guide is provided at a center portion and projects toward the sheet member. The planer guide parts are provided on both sides of the convex guide part. A first gap formed between the convex guide part and the sheet member is narrower than a second gap formed between the planer guide part and the sheet member.