Sheet processing device, image forming device provided with the same, and folded sheet pressing method

A sheet processing device that presses a folded sheet bundle, comprising:

• a device frame;
• a first conveying member that conveys the folded sheet bundle having a folding loop;
• a pair of pressing members that presses the folding loop in a thickness direction thereof;
• a support unit that is mounted to the device frame and supports a plurality of rows of pressing member pairs such that intervals therebetween in a row direction are reduced stepwise;
• and
• a second conveying member that makes the folding loop pass through the support unit in a direction that the intervals of the plurality of rows of pressing member pairs in the row direction are reduced stepwise,
• wherein the second conveying member conveys the folded sheet bundle in a direction crossing a sheet conveying direction of the first conveying member to press the folding loop by means of the plurality of rows of pressing member pairs.

A sheet processing device that presses a folded sheet bundle, comprising:

• a device frame,
• a first conveying member that conveys the folded sheet bundle having a folding loop;
• a second conveying member that conveys the folded sheet bundle in a direction crossing a conveying direction of the first conveying member;
• a pair of pressing members that presses the folding loop of the folded sheet bundle conveyed by the second conveying member in a thickness direction of the folding loop;
• a support unit that is mounted to the device frame and supports a plurality of rows of pressing member pairs arranged from an upstream side to a downstream side in a crossing direction such that intervals therebetween in a row direction are reduced stepwise;
• and
• a control unit that controls the first and second conveying members,
• wherein the control unit allows selection of whether or not to perform pressing for the folding loop by the support unit depending on a sheet hand-over position from the first conveying member to the second conveying member.

A sheet pressing method of a sheet processing device, comprising the steps of:

• a providing step of providing a pair of pressing members that presses a folding loop of a folded sheet bundle in a thickness direction thereof, a pressing member pairs being arranged such that intervals therebetween in a row direction are reduced stepwise, and a moving member that makes the folding loop of the folded sheet bundle pass in a direction that the intervals of plurality of rows of pressing member pairs in the row direction are reduced stepwise,
• a carrying-in step of carrying the folding loop of the folded sheet bundle into the pressing member pairs by the moving member,
• a conveying step of, following the carrying-in step, continuously conveying the folding loop of the folded sheet bundle in the direction that the intervals of the plurality of rows of pressing member pairs in the row direction are reduced stepwise by the moving member, and
• a passage completion step of, following the conveying step, passing the folding loop of the folded sheet bundle through the pressing member pairs by the moving member,
• wherein the folding loop of the folded sheet bundle is sequentially pressed.