Method and device for separation of sheets of a recording carrier from a stack

• US 20050280199A1
• Filed: 04/27/2005
• Published: 12/22/2005
• Est. Priority Date: 05/03/2004
• Status: Abandoned Application

• Current Assignee: BDT AG
• Original Assignee: BDT AG
• Inventors: Niggemann, Karl-Heinz, Bantle, Ludwig, Steinhilber, Helmut
• Application Number:
  US11/115,650
• Publication Number:
  US 20050280199A1
• Time in Patent Office: Days
• US Class Current: 271/121
• CPC Class Codes: B65H 3/56 Elements, e.g. scrapers, fingers, needles, brushes, acting on separated article or on edge of the pile B65H3/52 takes precedence

Abstract

For separation of sheets of a recording carrier from a stack for feeding to an office machine, printer or the like, a pick-up device is placed on the rear end of the stack. The pick-up device pushes the sheets against the belt in overlapping fashion, which raises the front edge of the first sheet arriving first from the stack. The holding element is then pivoted into the gap between the first sheet and the second sheet. The holding element holds the second sheet on the stack and forces the first sheet against a given transport roller with a pressure roller. Separation elements are pushed between the first sheet and the second sheet in order to separate the first sheet from the second sheet. The pick-up device is raised so that the first sheet can be withdrawn by the transport rollers from the stack and fed to the ejection rollers.

Claims

1. Method for separation of sheets of a recording carrier from a stack for feeding to an office machine, a printer or the like with the following steps:

exerting a pick-up effect on the uppermost first sheet of the stack on its rear end region in the feed direction, through which the upper sheets are pushed forward in overlapping fashion against a stop in the feed direction, wherein the first sheet is first to reach the stop with its front edge facing in the feed direction because of overlapping;

raising the front edge of the first sheet by the stop from the stack so that a gap is formed between the front edge of the first sheet and the front edge of the corresponding next second sheet;

moving at least one holding element into the gap between the front edge of the first sheet and the second sheet;

grasping the front edge of the first sheet by the transport rollers and holding the second sheet by the holding element on the stack;

releasing the first sheet from the pick-up effect and pushing at least one separation element between the first sheet and the second sheet and separating the first sheet flatly from the second sheet;

pulling the first sheet from the stack by the transport rollers and transporting it to ejection rollers by which it is grasped;

moving the at least one holding element out from the stack and releasing the second sheet and retracting the at least one separation element from the stack;

feeding the first sheet by the ejection rollers to the office machine or the like; and

exerting the pick-up effect on the rear end region of the second sheet that is exposed by pulling off of the first sheet so that the corresponding separation and feed cycle for the second sheet begins.

2. The method according to claim 1, wherein the first sheet is moved with a greatest advance and the subsequent sheets with a smaller advance.

3. The method according to claim 1, wherein a pick-up device is positioned on the uppermost sheet in order to exert the pick-up effect and raised from the uppermost sheet in order to release it from the pick-up effect.

4. The method according to claim 1, wherein the at least one holding element forces the front edge of the uppermost sheet against the transport roller.

5. The method according to claim 1, wherein the at least one separation element is retracted essentially simultaneously with withdrawal of the uppermost sheet from the stack.

6. The method according to claim 3, wherein the pick-up device is initially placed on the rear end region of the uppermost sheet without a pick-up effect and the pick-up effect is only started after contact.

7. The method according to claim 1, wherein the stop is moved upward at a steep angle with reference to sheet plane of the stack and the front edge of the corresponding uppermost sheet is carried along with friction or shape mating.

8. A device for separation of sheets of a recording carrier from a stack for feeding to an office machine, printer or the like for execution of the method according to claim 1, wherein a pick-up device can be positioned on the rear end region of the stack with reference to the feed direction of sheets, wherein the upper sheets of the stack are pushed against the stop in overlapping fashion by the pick-up device, wherein the stop raises the front edge of the uppermost sheet from the subsequent retracted second sheet, wherein at least one holding element can be moved between the front edge of the raised first sheet and the second sheet, wherein the at least one holding element secures the second sheet of the stack on the stack in the position moved into the stack, wherein the front edge of the corresponding first sheet raised by the stop is grasped by the transport rollers and pulled off, wherein at least one separation element can be pushed between the first sheet raised on its front edge and the second sheet and wherein the transport roller transports the corresponding first sheet to the ejection rollers.

9. The device according to claim 8, wherein the at least one holding element can be pivoted around an axis parallel to the front edge of the stack and engages with a finger between the raised front edge of the first sheet and the second sheet sits with this finger on the second sheet and holds it on the stack and with its top brings the first sheet into engagement with the transport rollers.

10. The device according to claim 9, wherein the at least one holding element has a freely rotatable pressure roller on its finger pivotable into the stack, which forces the first sheet against the drivable transport roller.

11. The device according to claim 8, wherein the at least one separation element is a strip, especially an electrically conducting strip and especially a steel strip, which can be pushed against the feed direction of sheets by the front side of the stack between the first sheet and the second sheet.

12. The device according to claim 8, wherein the stop consists of at least one endlessly revolving drivable belt, whose run facing the stack runs up at a steep angle and entrains the front edge of the first sheet lying against it by friction.

13. A device for separation of sheets of a recording carrier from a stack for feeding to an office machine, printer or the like comprising

means for exerting a pick-up effect on the uppermost first sheet of the stack on its rear end region in the feed direction and for moving the first sheet,

a stop for stopping a movement of a picked up sheet and for raising the front edge of the first sheet;

means for moving at least one holding element by the front side of the stack into a gap between the front edge of the first sheet and a second sheet;

transport rollers for grasping the front edge of the first sheet;

a holding element for holding the second sheet on the stack;

means for releasing the first sheet from the pick-up effect and pushing at least one separation element between the first sheet and the second sheet and separating the first sheet flatly from the second sheet,

ejection rollers for grasping the first sheet pulled from the stack by the transport rollers;

means for moving the at least one holding element out from the stack and releasing the second sheet and retracting the at least one separation element from the stack, wherein the ejection rollers feed the first sheet to the office machine or the like, and wherein means exert the pick-up effect on the rear end region of the second sheet that is exposed by pulling off of the first sheet so that the corresponding separation and feed cycle for the second sheet begins.

14. The device according to claim 13, wherein the means for exerting a pick-up effect are a pick-up device which can be positioned on the rear end region of the stack with reference to the feed direction of sheets, wherein the upper sheets of the stack are pushed against the stop in overlapping fashion by the pick-up device, wherein the stop raises the front edge of the uppermost sheet from the subsequent retracted second sheet, wherein at least one holding element can be moved by the front side of the stack between the front edge of the raised first sheet and the second sheet, wherein the at least one holding element secures the second sheet of the stack on the stack in the position moved into the stack, wherein the front edge of the corresponding first sheet raised by the stop is grasped by the transport rollers and pulled off, wherein at least one separation element can be pushed between the first sheet raised on its front edge and the second sheet and wherein the transport roller transport the corresponding first sheet to the ejection rollers.

15. The device according to claim 14, wherein the at least one holding element can be pivoted around an axis parallel to the front edge of the stack and engages with a finger between the raised front edge of the first sheet and the second sheet, sits with this finger on the second sheet and holds it on the stack and with its top brings the first sheet into engagement with the transport rollers.

16. A device for separation of sheets of a recording carrier from a stack for feeding to an office machine, printer or the like comprising:

a pick-up device which can be positioned on a rear end region of the stack with reference to the feed direction of sheets,

a stop against which upper sheets of the stack are pushed in overlapping fashion by the pick-up device, wherein the stop raises the front edge of the uppermost sheet from the subsequent retracted second sheet,

at least one holding element which can be moved by a front side of the stack between a front edge of a raised first sheet and the second sheet, wherein the at least one holding element secures the second sheet of the stack on the stack in the position moved into the stack, wherein the front edge of the corresponding first sheet raised by the stop is grasped by transport rollers and pulled off,

at least one separation element which can be pushed between the first sheet raised on its front edge and the second sheet and wherein the transport roller transport the corresponding first sheet to ejection rollers.

17. The device according to claim 16, wherein the at least one holding element can be pivoted around an axis parallel to the front edge of the stack and engages with a finger between the raised front edge of the first sheet and the second sheet, sits with this finger on the second sheet and holds it on the stack and with its top brings the first sheet into engagement with the transport rollers.

18. The device according to claim 17, wherein the at least one holding element has a freely rotatable pressure roller on its finger pivotable into the stack, which forces the first sheet against the drivable transport roller.

19. The device according to claim 16, wherein the at least one separation element is a strip, especially an electrically conducting strip and especially a steel strip, which can be pushed against the feed direction of sheets by the front side of the stack between the first sheet and the second sheet.

20. The device according to claim 16, wherein the stop consists of at least one endlessly revolving drivable belt, whose run facing the stack runs up at a steep angle and entrains the front edge of the first sheet lying against it by friction.