Sheet stacker for thin or weak print media
AssigneeCanon Production Printing Holding B.V.
InventorsPeter J. W. Van Dongen, Hermanus M. Kuypers, Frank J. W. Zeelen
Life of this patent
Estimating the term…
Abstract
When using a flipping wheel to flip sheets of weak or long media, there is a risk that these sheets collapse upon themselves. To reduce this risk, a method of stacking sheets includes flipping a sheet while holding its leading edge and bringing the leading edge down towards a stack support; bringing a trailing portion of the sheet into contact with a guide member positioned over the stack support; forming an overpressure in an inner volume of the bent sheet during flipping, while its trailing portion is in contact with the guide member; and maintaining the overpressure and contact while a trailing edge of the sheet travels along the guide member.
Claims16
A method of stacking sheets, comprising the steps of:
- flipping a sheet while holding a leading edge of the sheet and bringing said leading edge down towards a stack support;
- bringing a trailing portion of the sheet into contact with a guide member positioned over the stack support;
- blowing gas into an inner volume of the sheet to form an overpressure in the inner volume of the sheet during flipping, while the trailing portion is in contact with the guide member, wherein the gas is blown in an inclined direction, aimed upwards and in a direction a trailing edge of the sheet moves along the guide member;
- maintaining said overpressure and contact while the trailing edge of the sheet travels along a contact surface of the guide member, wherein the contact surface is stationary while in contact with the trailing edge, and
- wherein the trailing portion contacts the guide member, such that gas is prevented from escaping from the inner volume along the trailing edge, at least until the trailing edge passes a release point on the guide member, the release point being determined by a length of sheet.
A sheet stacker for printed media, comprising:
- a flipping device for flipping a sheet onto a stack support or a stack of sheets on said stack support, wherein the flipping device comprises a flipping wheel with at least one slot for receiving a leading edge of the sheet;
- a guide member positioned over the stack support and adjacent the flipping device to confine a flipping volume for the sheet;
- and
- a gas nozzle positioned at the flipping device and inclined upwards towards the guide member, the gas nozzle being configured to blow gas such that a trailing portion of the sheet is pressed against the guide member by a gas flow from the gas nozzle as the trailing portion travels along a guide surface of the guide member, wherein the guide surface is configured to be stationary while in contact with the trailing portion.
A method of stacking sheets, comprising the steps of:
- flipping a sheet while holding a leading edge of the sheet and bringing said leading edge down towards a stack support;
- bringing a trailing portion of the sheet into contact with a guide member positioned over the stack support;
- blowing gas into an inner volume of the sheet to form an overpressure in the inner volume of the sheet during flipping, while the trailing portion is in contact with the guide member, wherein the gas is blown in an inclined direction, aimed upwards and in a direction a trailing edge of the sheet moves along the guide member;
- and
- maintaining said overpressure and contact while the trailing edge of the sheet travels along the guide member, wherein the trailing portion contacts the guide member, such that gas is prevented from escaping from the inner volume along the trailing edge, at least until the trailing edge passes a release point on the guide member, the release point being determined by a length of sheet.
Dependencies are inferred from the claim text.