Retard roll enhancement

• US 5,211,388 A
• Filed: 06/03/1992
• Issued: 05/18/1993
• Est. Priority Date: 06/03/1992
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Walluk, Edward L.
• Primary Examiner(s): SCHACHER, RICHARD
• Application Number:
  US07/892,879
• Time in Patent Office: 349 Days
• Field of Search: 271/121, 271/122, 271/124, 271/125
• US Class Current: 271/122
• CPC Class Codes: B65H 3/063 separating from the bottom of pile B65H3/0615, B65H3/0623 take precedence
• CPC Class Codes: B65H 3/5284 Retainers of the roller type, e.g. rollers

Abstract

An apparatus for feeding individual sheets from the bottom of a sheet stack. The sheet stack is placed in the paper tray with the lead edge abutting the sheet feeding apparatus. The face of the stack rests against the main fang. As the feed roll forwards the sheets from the bottom of the stack to a position under the main fang, further sheet separation occurs as the lead edges of the sheets strike a substantially arcuate member located between the main fang and the retard roll. The curved portion of the member which has a larger radius of curvature than the retard member causes the sheets to be shingled out permitting a single sheet to pass under the retard roll and to be advanced by the feed roll.

Claims

1. A sheet feeding apparatus adapted to advance sheets from a stack of sheets, comprising:

means for supporting the stack of sheets;

means, mounted adjacent said support means, for advancing sheets from the stack;

a retard member having a substantially arcuate surface, said retard member comprising a ribbed elastomeric roll in circumferential contact with a portion of said advancing means so as to form a nip therebetween ; and

means for queuing and separating sheets being advanced by said advancing means from the stack, said queuing and separating means comprising a substantially planar member adapted to engage a lead edge of one portion of the sheets of the stack so as to initially separate a plurality of sheets from one side of the stack and a ring having a radius of curvature greater than the arcuate surface of said retard member, said ring having an interior diameter greater than the diameter of said ribbed elastomeric roll disposed so that said ring encircles said elastomeric roll and being adapted to engage a portion of the sheets of the stack.

2. The apparatus according to claim 1, wherein said advancing means advances successive bottommost sheets from the stack being supported by said support means.

3. An apparatus according to claim 2, wherein said sheet advancing means comprises:

a nudger adapted to engage successive bottommost sheets of the stack being supported on said support means; and

a feed roll in circumferential frictional contact with said ribbed elastomeric roll so as to form a drive nip therebetween to drive successive bottommost sheets of the stack.

4. An electrophotographic printing machine of the type in which a sheet is advanced from a sheet stack, wherein the improvement comprises:

means for supporting the stack of sheets;

means, mounted adjacent said support means, for advancing sheets from the stack;

a retard member having a substantially arcuate surface, said retard member comprising a ribbed elastomeric roll in circumferential contact with a portion of said advancing means so as to form a nip therebetween; and

means for queuing and separating sheets being advanced by said advancing means from the stack, said queuing and separating means comprising a substantially planar member adapted to engage a lead edge of one portion of the sheets of the stack so as to initially separate a plurality of sheets from one side of the stack and a ring having a radius of curvature greater than the arcuate surface of said retard member, said ring having an interior diameter greater than the diameter of said ribbed elastomeric roll disposed so that said ring encircles said elastomeric roll and being adapted to engage a portion of the sheets of the stack.

5. The printing machine according to claim 4, wherein said advancing means advances successive bottommost sheets from the stack being supported by said support means.

6. A printing machine according to claim 5, wherein said sheet advancing means comprises:

a nudger adapted to engage successive bottommost sheets of the stack being supported on said support means; and

a feed roll in circumferential frictional contact with said ribbed elastomeric roll so as to form a drive nip therebetween to drive successive bottommost sheets of the stack.

7. The printing machine of claim 4, wherein the sheet being advanced is a copy sheet.

8. The printing machine of claim 4, wherein the sheet being advanced is an original document.

9. A module sheet feeding machine adapted to be removably positioned adjacent a sheet inlet of a printing machine, comprising:

means for supporting a stack of sheets;

means, mounted adjacent said support means, for advancing sheets from the stack to the sheet inlet of the printing machine;

a retard member having a substantially arcuate surface;

said retard member comprising a ribbed elastomeric roll in circumferential contact with a portion of said advancing means so as to form a nip therebetween; and

means for queuing and separating sheets being advanced by said advancing means from the stack, said queuing and separating means comprising a substantially planar member adapted to engage a lead edge of one portion of the sheets of the stack so as to initially separate a plurality of sheets from one side of the stack and a ring having a radius of curvature greater than the arcuate surface of said retard member, said ring having an interior diameter greater than the diameter of said ribbed elastomeric roll disposed so that said ring encircles said elastomeric roll and being adapted to engage a portion of the sheets of the stack.

10. The printing machine according to claim 9, wherein said advancing means advances successive bottommost sheets from the stack being supported by said supported means.

11. A printing machine according to claim 10, wherein said sheet advancing means comprises:

a nudger adapted to engage successive bottommost sheets of the stack being supported on said support means; and

a feed roll in circumferential frictional contact with said ribbed elastomeric roll so as to form a drive nip therebetween to drive successive bottommost sheets of the stack.