Sheet stack handler comprising a sheet stacker and/or sheet feeder for a printer
A sheet stack handler includes first and second liftable stack supports, a sheet engager for stacking a sheet onto a stack of sheets, a lift assembly, and a translation mechanism. The lift assembly moves the first or second liftable stack supports between a bottom and top position. A stack holding volume is defined between the bottom and top positions. The lift assembly positions a top sheet of the stack of sheets and/or on the first or second liftable stack supports inside the stack holding volume at an operative level to allow the sheet engager to stack a new sheet and/or separate the top sheet from the respective stack of sheets. The translation mechanism translates one of the first and second liftable stack supports while supporting a sheet stack between a buffer position outside of the stack holding volume and an active position inside the stack holding volume.
1 . A sheet stack handler comprising a sheet stacker and/or a sheet feeder comprising:
a first and a second, liftable stack support, each configured to support a stack of sheets;
an individual sheet engager comprising a sheet-to-stack supplier for stacking a sheet onto a stack of sheets one of the first or second, liftable stack supports and/or a sheet-from-stack separator for separating a sheet from a stack of sheets on one of the first and second liftable stack supports, wherein the individual sheet engager is configured to transport sheets in a transport direction parallel to a transport part for feeding sheets to and/or receiving sheets from the individual sheet engager,
a lift assembly for moving the first and/or second liftable stack support between a bottom position and a top position, which are respectively positioned spaced apart from and adjacent the individual sheet engager, such that a stack holding volume is defined between the bottom position and top position, and wherein the lift assembly is further configured to position a top sheet of the stack on the first and/or second, liftable stack support inside the stack holding volume at an operative level of the individual sheet engager, such that the individual sheet engager can stack a new sheet onto the top sheet and/or separate the top sheet from the respective stack, wherein the lift assembly comprises a first lift for lifting and/or lowering the first, liftable stack support and a second lift for lifting and/or lowering the second, liftable stack support independent of the first, liftable stack support; and
a translation mechanism configured to translate at least one of the first and second, liftable stack supports while supporting a stack of sheets between a buffer position outside of and on one side of the stack holding volume and an active position inside the stack holding volume, wherein a translation direction of the translation mechanism is perpendicular to the transport direction and to the lifting direction, and wherein the translation mechanism comprises a sliding frame that connects the first, liftable stack support to the second, liftable stack support, such that the first and second liftable stack supports are movable in unison back and forth along a straight, linear trajectory in the translation direction between the active position and the buffer position.
2 . The sheet stack handler according to claim 1 , wherein the sliding frame is a rigid frame that on it defines fixed, non-overlapping positions for the first and second, liftable stack supports.
3 . The sheet stack handler according to claim 1 , wherein the first and the second lifts are mounted onto the sliding frame besides one another in the translation direction.
4 . A printer comprising sheet stack handler according to claim 1 .
5 . The sheet stack handler according to claim 1 , wherein the first and second, liftable stack supports are each configured to support a pallet whereupon the stack of sheets is provided.
6 . A sheet stack handler comprising a sheet stacker and/or a sheet feeder comprising:
a first and a second, liftable stack support, each configured to support a stack of sheets;
an individual sheet engager comprising a sheet-to-stack supplier for stacking a sheet onto a stack of sheets one of the first or second, liftable stack supports and/or a sheet-from-stack separator for separating a sheet from a stack of sheets on one of the first and second liftable stack supports;
a lift assembly for moving the first and/or second liftable stack support between a bottom position and a top position, which are respectively positioned spaced apart from and adjacent the individual sheet engager, such that a stack holding volume is defined between the bottom position and top position, and wherein the lift assembly is further configured to position a top sheet of the stack on the first and/or second, liftable stack support inside the stack holding volume at an operative level of the individual sheet engager, such that the individual sheet engager can stack a new sheet onto the top sheet and/or separate the top sheet from the respective stack, wherein the lift assembly comprises a first lift for lifting and/or lowering the first, liftable stack support and a second lift for lifting and/or lowering the second, liftable stack support independent of the first, liftable stack support;
a translation mechanism configured to translate at least one of the first and second, liftable stack supports while supporting a stack of sheets between a buffer position outside of and on one side of the stack holding volume and an active position inside the stack holding volume, wherein two buffer positions are provided on opposite sides of the stack holding volume, such that moving one of the of the first and second, liftable stack support from one of the buffer positions to the active position moves the other of the first and second, liftable stack supports from the active position to the other one of the buffer positions.
7 . The sheet stack handler according to claim 6 , further comprising a housing surrounding the stack holding volume, wherein the buffer positions extend outside said housing, so that in the buffer positions the first and second, liftable stack supports are accessible for loading and/or unloading a pallet therefrom.
8 . A sheet stack handler comprising a sheet stacker and/or a sheet feeder comprising:
a first and a second, liftable stack support, each configured to support a stack of sheets;
an individual sheet engager comprising a sheet-to-stack supplier for stacking a sheet onto a stack of sheets one of the first or second, liftable stack supports and/or a sheet-from-stack separator for separating a sheet from a stack of sheets on one of the first and second liftable stack supports;
a lift assembly for moving the first and/or second liftable stack support between a bottom position and a top position, which are respectively positioned spaced apart from and adjacent the individual sheet engager, such that a stack holding volume is defined between the bottom position and top position, and wherein the lift assembly is further configured to position a top sheet of the stack on the first and/or second, liftable stack support inside the stack holding volume at an operative level of the individual sheet engager, such that the individual sheet engager can stack a new sheet onto the top sheet and/or separate the top sheet from the respective stack;
a translation mechanism configured to translate at least one of the first and second, liftable stack supports while supporting a stack of sheets between a buffer position outside of and on one side of the stack holding volume and an active position inside the stack holding volume; and
a translation guide beam along which the second, liftable stack support is movable when moving in and out of the stack holding volume, wherein the translation guide beam extends parallel to a horizontal direction during use,
wherein the lift assembly further comprises:
a first lift for moving the first, liftable stack support between the bottom position and the top position, and wherein the second, liftable stack support is movable in a direction independent of the first, liftable stack support perpendicular to lifting directions of both the first and second liftable stack supports between the buffer position and an active position wherein the second, liftable support is inside the stack holding volume and extends over the first, liftable stack support, such that the individual sheet engager is able to stack and/or separate sheets on and/or from a second stack of sheets on the second, liftable stack support; and
a second lift for lowering and raising the second, liftable stack support independently of the first lift, wherein the second, liftable stack support is dimensioned and positioned be inserted into the stack holding volume without contacting the first lift at least between the top and bottom positions,
wherein the second lift is positioned outside the stack holding volume when the second, liftable stack support has been inserted into the stack holding volume.
9 . The sheet stack handler according to claim 8 , wherein the second, liftable stack support does not overlap with lifting lines of the first lift, when viewed in the vertical direction.
10 . The sheet stack handler according to claim 8 , further comprising a controller configured to determine when a number of sheets in the stack on the first, liftable stack support matches or crosses a predetermined threshold, to then control the first, liftable stack support to be positioned at the bottom position, followed by controlling the second, liftable stack support to be inserted into the stack holding volume, and to transmit stack support information for prompting said information on a user interface.