Sheet inverter and method for inverting a sheet
AssigneeEastman Kodak Company
InventorsDimitrios Kostudis, Volker Otto, Rolf Spilz
Life of this patent
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Abstract
Sheet inverters and methods for inverting sheets are provided that guide longer length receivers through a 180 degree turn while the receivers are being transported along a transport path while reducing the possibility of jams, the extent of sheet stress experienced during inversion and reducing the risk of creating print artifacts.
Claims17
A sheet inverter for inverting sheets in a printing machine, said sheet inverter comprising:
- a first pair of spaced apart rollers having a first endless belt entrained thereabout in a figure eight configuration such that the first endless belt has a 180° twist in each section extending between said first pair of rollers;
- a second pair of spaced apart rollers having a second endless belt entrained thereabout in a figure eight configuration such that the second endless belt has a 180° twist in each section extending between said second pair of rollers, said first and second pairs of rollers being arranged adjacent to each other such that one section of said first endless belt and one section of said second endless belt, each having said 180° twist, contact each other to form a transport path therebetween, said transport path having a 180° twist, said twist of the transport path imparting a central portion of a sheet, which is sandwiched between the belts, to turn over by 180° by following the twist in the transport path while the sheet is transported there along through the inverter;
- and
- at least one guide unit, said guide unit being arranged to provide guidance to a first lateral portion of a sheet while it is transported along the transport path through the inverter, said guide unit has a turning section, which crosses over the transport path from one side to an opposite side thereof and which is arranged to guide the first lateral portion of said sheet to turn and move over the transport path by imparting a turning movement to the first lateral portion of the sheet, the imparted turning motion having a substantially higher angular rate than a turning motion imparted by the twist in the respective section of the transport path.
A method for inverting a sheet as it is transported through a sheet inverter having a first pair of spaced apart rollers having a first endless belt entrained thereabout in a figure eight configuration, such that the first endless belt has a 180° twist in each section extending between said first pair of rollers, and a second pair of spaced apart rollers having a second endless belt entrained thereabout in a figure eight configuration, such that the second endless belt has a 180° twist in each section extending between said second pair of rollers, said first and second pairs of rollers being arranged adjacent to each other such that one section of said first endless belt and one section of said second belt, each having said 180° twist, contact each other to form a transport path therebetween, said transport path having a 180° twist, said method comprising:
- causing the first and second endless belts to circulate about the first and second rollers such that the belt sections forming the transport path move in the same direction and at the same speed;
- transporting a central portion of a sheet between the belt sections forming the transport path such that it is sandwiched by the belt sections and moved therewith;
- imparting a turning motion to the central portion of the sheet by causing the central portion to follow the twist in the transport path while the sheet is transported along the transport path;
- and
- imparting a turning movement to a first lateral portion of the sheet by at least one guide to cause the first lateral portion of said sheet to turn and thereby move over the transport path, the imparted turning motion having a substantially higher angular rate than a turning motion imparted to the central portion of the sheet in the respective section along the transport path.
Dependencies are inferred from the claim text.