Spine formation device, bookbinding system, and spine formation method

A bookbinding system comprising:

• an image forming apparatus to form images on sheets of recording media;
• and
• a spine formation device for forming a spine of a bundle of folded sheets, the spine formation device comprising:
• a sheet conveyer that conveys the bundle of folded sheets with a folded portion of the bundle forming a front end portion of the bundle;
• a clamping unit disposed downstream from the sheet conveyer in a sheet conveyance direction in which the bundle of folded sheets is transported, for squeezing the folded portion of the bundle in a direction of thickness of the bundle;
• a contact member disposed downstream from the clamping unit in the sheet conveyance direction and including a flat contact surface against which the folded portion of the bundle is pressed;
• a controller comprising a CPU and operatively connected to the sheet conveyer as well as the clamping unit to cause the bundle of folded sheets to bulge by stopping the sheet conveyer after the bundle of folded sheets is transported a predetermined conveyance distance downstream in the sheet conveyance direction from a contact position between the contact member and the folded portion of the bundle, the predetermined distance set in accordance with a predetermined sheet-related variable, and to cause the clamping unit to squeeze a bulging portion of the bundle created between the sheet conveyer and the contact member with the folded potion pressed against the contact member;
• and
• an input unit via which a user selects whether the predetermined conveyance distance is set automatically or manually.

A spine formation method used in a spine formation device including a sheet conveyer, a clamping unit, and a contact member disposed, in that order, in a sheet conveyance direction in which a bundle of folded sheets is transported, the spine formation method comprising:

• transporting the bundle of folded sheets with the folded portion of the bundle forming a front end portion of the bundle in the sheet conveyance direction;
• causing the bundle of folded sheets to bulge by stopping the bundle of folded sheets after the bundle of folded sheets is transported a predetermined conveyance distance downstream in the sheet conveyance direction from a contact position between the contact member and the folded portion of the bundle of folded sheets;
• and
• forming a spine of the bundle of folded sheets by squeezing a bulging portion of the bundle of folded sheets created between the sheet conveyer and the contact member in the direction of thickness of the bundle with the folded portion pressed against the contact member,
• wherein the predetermined distance is set in accordance with a predetermined sheet-related variable;
• and
• wherein a user selects whether the predetermined conveyance distance is set automatically or manually via an input unit.