EP0138065A1

EP0138065A1 - Paper sheet feeder

Info

Publication number: EP0138065A1
Application number: EP84110912A
Authority: EP
Inventors: Douglas Roger Arnoldi; Richard Arthur Sloan, Jr.; George F. Gustafson
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1983-09-15
Filing date: 1984-09-12
Publication date: 1985-04-24

Abstract

Disclosed is a paper sheet feeder which separates and transports single sheets of paper from the top of a paper stack (12) to a separate device such as a printer, copier or scanner. The feeder's capabilities include the ability to handle mixtures of different types, thicknesses and sizes of paper without modification of the feeder. The feeder's capabilities are achieved with a minimum number of parts and complexity by utilizing rotating flexible blades (18) (20) to transport several sheets of paper over a separating wheel (26) which reverse feeds all of the several sheets of paper except the top sheet.

Description

Field of the Invention

This invention relates in general to a paper sheet feeder. More particularly, this invention relates to a paper sheet feeder which separates and transports a single sheet of paper from the top of a stack of paper to a separate device such as a printer, copier or scanner.

Background of the Invention

Paper sheet feeders are well known in the prior art, finding application in feeding sheets of paper, one at a time, into separate using devices such as typewriters, printers, copiers and scanners.
In many of the prior art feeders, the tray containing the paper supply must be repositioned as the paper supply is depleted. Additionally, most prior art feeders require relatively expensive and complex mechanisms to move a single sheet of paper from the paper supply to the separate using device. Further, many prior art sheet feeders include constraining mechanisms at the edges of the paper supply stack, and therefore require the paper all to be of a uniform width. In addition, many prior art paper feeders are limited to handling paper stock of a uniform type or thickness.
It is a general object of the present invehtion to provide an improved paper sheet feeder which overcomes these and other drawbacks of the prior art.
It is an additional object of the present invention to provide a paper sheet feeder which can handle a mixture of different types, thicknesses and sizes of papers.
It is a further object of the present invention to provide a paper sheet feeder which can separate and transport single sheets of paper from the top of a stack of paper to a separate device such as a printer, copier or scanner.
It is still a further object of the present invention to provide a paper sheet feeder which does not require a significant pull-out force on a sheet of paper after the sheet of paper has been transported to a separate device.
It is another object of the present invention to provide a paper sheet feeder having fewer and simpler parts than prior art sheet feeders.
It is still another object of the present invention to provide a paper sheet feeder employing rotating flexible blades which conform to the height of the paper supply and thereby eliminate the need for relative motion between a variable height paper supply and the feeding mechanism.
The foregoing and other objects, features and advantages of the present invention will be apparent from the following description of the preferred embodiment of the invention, as illustrated in the accompanying drawings.

Summary of the Invention

In accordance with the present invention, a paper supply is positioned on the lower level of a two-level paper tray, each level of the tray including a flat section, an inclined section connecting the upper and lower levels. Positioned above the upper tray level is a first rotatable shaft on which are radially mounted a pair of flexible elastomer blades offset from one another by approximately 120 degrees. As the first shaft is rotated, one of the blades contacts the top of the paper supply and drags several top sheets up the inclined tray section and onto the upper tray level.
A second rotatable shaft, positioned below the upper tray level, has a separating wheel mounted on it. The separating wheel passes through a cutout section in the upper tray level so that paper passing over the upper tray level contacts the outer surface of the separating wheel. As the several sheets approach the separating wheel, the first blade is flexed to a more curved shape, increasing the pressure on the several sheets. The restraining action of the separating wheel stops and reverse feeds all of the several sheets except the top one.
Continued rotation of the first shaft causes the second flexible blade to contact the top sheet of paper prior to the first blade passing the separator wheel and kicking out to a free position. Thus, the second blade maintains the forward motion of the top sheet toward the end of the upper tray level.

Brief Description of the Drawings

FIG. 1 shows a perspective view, with sections cut away, of the present paper sheet feeder in its rest position prior to or after feeding a sheet of paper.
FIG. 2 shows a sectional view of the present paper sheet feeder halfway through a feed cycle, at which time the top sheets have reached the separating wheel and maximum reverse feeding is occurring.

Description of the Preferred Embodiment

FIG. 1 shows the preferred embodiment of the paper sheet feeder 10 in a rest position.
The paper supply 12 is positioned on the lower section 32 of paper tray 14. For clarity and ease of illustration, portions of the tray 14 shown in FIG. 1 have been broken away. Thus, those skilled in the art will appreciate that in actuality the upper, lower and inclined sections 34, 32 and 28, respectively, of tray 14 extend beyond the edge 36 of tray 14. Further, it should be noted that the upper and inclined sections 34 and 28 extend longitudinally across the rear side of separating wheel 26 so that cutout section 38 actually has a fourth side. In the preferred embodiment of the invention, sheets of paper of various widths may be included in the paper supply 12. Because of this capability, in the preferred embodiment no side walls are provided on the tray 14.
A rotatable shaft 16 is positioned as shown in FIG. 2 above the paper tray 14. For clarity and ease of illustration, the frame which supports the shaft with its axis parallel to the top surface of tray 14 is not shown. Additional means (not shown) are connected to one end of shaft 16 in order to selectively rotate shaft 16 in the direction shown. Both the frame and means for rotating shaft 16 can constructed from conventional mechanisms which are well known in the prior art.
As shown in FIG. 1, two flexible elastomer blades 18, 20 are mounted on the shaft 16. As will be explained later in more detail, these blades 18, 20 serve to transport the sheets of paper from the top of the paper supply 12 toward the end 22 of the tray 14.
A second rotatable shaft 24 is positioned as shown in FIG. 2 below paper tray 14. The frame used to support shaft 16 also supports shaft 24, each shaft's longitudinal axis being in parallel alignment. In the preferred embodiment, the same means used to rotate shaft 16 also rotates shaft 24 in the same direction. Alternately, a second drive means may be utilized to rotate shaft 24 in the indicated direction. A separating wheel 26 is mounted on shaft 24 in the position shown in FIG. 1. The surface speed of separating wheel 26 is approximately the same as the feed rate of flexible blades 18 and 20. As will be discussed below in more detail, the separating wheel 26 moves in a direction counter to the paper feed direction in order to restrain excess paper from being moved from the paper supply 12 to the end 22 of tray 14.
The sheet feeder 10 is designed to separate and transport a single sheet of paper from the top of the stack 12 of paper to a separate device (not shown) such as a printer, copier or scanner. With the elements of the sheet feeder 10 now defined, its operation will now be described in detail.
FIG. 1 shows the paper feeder in a rest position. In the rest position, neither shaft 16 or 24 is being rotated and the blades 18, 20 are not in contact with the paper supply 12 or the tray 14. Thus, no restraint exists on the paper. Therefore, in the rest position, a previously fed sheet of paper can be transported away by the receiving mechanism of the separate device with essentially no drag.
In order to feed a sheet of paper from paper supply 12, the drive mechanism(s) are activated to rotate both shafts 16 and 24 in the direction indicated. The rotation of shaft 16 moves flexible blade 18 into contact with the top of the stack 12 of paper and drags several of the top sheets of paper up the inclined section 28 of tray 14. As these several sheets of paper approach separating wheel 26, blade 18 is flexed to a more curved shape (see FIG. 2), thus increasing the pressure on the several sheets of paper.
The surfaces of each of the blades 18,20 are fabricated so that their coefficient of friction is higher than that of the paper's surface and the surface 30 of separating wheel 26. As a result, as blade 18 moves the several sheets of paper over the surface 30 of the separating wheel 26 and presses down against wheel 26, the separating wheel 26 exerts a restraining force on all of the several sheets of paper except the top sheet. This restraining force stops and reverse feeds all of the several sheets of paper except the top sheet due to coefficient of friction of blade 18 being higher than that of the separating wheel 26 and paper. This reverse feeding action causes additional sheets which start to follow the top sheet to be fed back to the top of the inclined section 28 of tray 14 (FIG. 2).
FIG. 2 shows the paper feeder 10 halfway through a feed cycle. At this point in the feed cycle, the several top sheets of paper have reached the separator wheel 26 and maximum reverse feeding of all of the several sheets of paper except the top sheet is occurring. Also at this point in the feed cycle, the second flexible blade 20 is contacting the top sheet of the several sheets of paper. As the feed cycle continues, the motion of the second blade 20 will maintain the movement of the top sheet of paper toward the end 22 of tray 14 as the first blade 18 passes separator wheel 26 and kicks out to a free position (as shown in dotted lines in FIG. 2).
In the preferred embodiment, the using device (not shown) which is to receive paper from the feeder 10 is positioned adjacent to the end 22 of tray 14. In the preferred embodiment, the feeder 1C transports the leading edge of the top sheet of the paper supply past the end 22 of tray 14 within one revolution of shaft 16. However, those skilled in the art will appreciate that variations in the position of shaft 16, the length of blades 18, 20 and the length of the top sheet of paper may result in more than one rotation of shaft 16 being required in order to transport a sheet of paper a sufficient distance for it to be engaged with the paper receiving mechanism of the printer or other using device.
In the preferred embodinent, after shaft 16 has been rotated one revolution tc cause the top sheet of paper to be transported to the end 22 of tray 14, the rotation of shafts 16 and 24 is shopped. At this point, the paper feeder 10 is back at it: rest position (FIG. 1). In this rest position, there is n< pressure between the top sheet of paper and the second sheet. Therefore, the second sheet of paper remains in -he tray 14 as the top sheet exits and is engaged with tie receiving mechanism of the printer or other using device. When the using device requires another sheet of paper, the feeder's 10 driving means are again activated to rotate shafts 16 and 24 and thereby feed another sheet from the paper supply 12.
Having shown and described the preferred embodiment of the present invention, we state that the subject matter which we regard as being our invention is particularly pointed out and distinctly claimed in the following claims. Those skilled in the art to which the present invention pertains will appreciate that equivalents or modification of, or substitutions for, parts of the specifically described embodiment of the invention may be made without departing from the scope of the invention as set forth in what is claimed.

Claims

1. A paper sheet feeder for supplying paper to a separate device, comprising:

tray means for supporting a paper supply; and

rotatable blade means, positioned above said tray means, for transporting single sheets from said paper supply to said separate device.

2. The paper sheet feeder in accordance with claim 1 further including restraining means, extending through a cutout section of said tray means, for preventing multiple sheets of said paper supply from being transported.

3. The paper sheet feeder in accordance with claim 2 wherein said rotatable blade means includes:

a first rotatable shaft;

at least one flexible blade connected to said first rotatable shaft.

4. The paper sheet feeder in accordance with claim 3 wherein said rotatable blade means includes two or more of said flexible blades.

5. The paper sheet feeder in accordance with claim 4 wherein said two flexible blades are offset from one another by approximately 120 degrees.

6. The paper sheet feeder in accordance with claim 3 wherein said restraining means includes:

a second rotatable shaft; and

a separating wheel mounted on said second rotatable shaft.

7. The paper sheet feeder in accordance with claim 6 further including means to rotate said first and second rotatable shafts in the same direction.

8. The paper sheet feeder in accordance with claim 6 wherein said tray means includes upper and lower sections, an inclined section connecting said upper and lower sections, said paper supply positioned on said lower section.

9. The paper sheet feeder in accordance with claim 8 wherein said cutout section is in the upper section of said tray means and a portion of said separating wheel passes through said cutout section.

10. The paper sheet feeder in accordance with claim 9 wherein the coefficient of friction of each one of said at least one flexible blades is higher than the coefficient of friction of both said separating wheel and said sheets of paper.

11. The paper sheet feeder in accordance with claim 6 wherein said rotatable blade means includes two of said flexible blades, each one of said flexible blades having a semitriangular shape, the base of each one of said semitriangular shapes connected along the length of said first rotatable shaft.

12. The paper sheet feeder in accordance with claim 7 wherein said rotating means simultaneously rotates both said first and second rotatable shafts in the same direction during a feed operation.

13. The paper sheet feeder in accordance with claim 12 wherein said first rotatable shaft is in a rest condition both before and after one of said feed operations, and each one of said flexible blades is free of said paper supply and said tray means when said first rotatable shaft is in said rest position.

14. The paper sheet feeder in accordance with claim 8 wherein the rotation of said first rotatable shaft causes a first one of said at least one flexible blades to contact the top of said paper supply and drag several top sheets of said paper supply up the inclined section of said tray means and further causes the top sheet of said several top sheets to be transported across the upper section of said tray means.

15. The paper sheet feeder in accordance with claim 14 wherein the rotation of said second rotatable shaft causes said separating wheel to rotate, the rotation of said separating wheel causing the reverse feeding of all of the several top sheets except the top sheet, whereby all of the several top sheets except the top sheet of said several top sheets are fed back to the inclined section of said tray means.

16. The paper sheet feeder in accordance with claim 14 wherein said separate device is positioned adjacent to the end of the upper section of said tray means, said separate device receiving the single sheet of paper transported by said rotatable blade means.

17. The paper sheet feeder in accordance with claim 14 wherein said rotatable blade means includes a second one of said at least one flexible blades and wherein the continued rotation of said first rotatable shaft causes the second one of said flexible blades to contact the top sheet of said several top sheets and maintain the motion of the top sheet of said several top sheets across the upper section of said tray means as the first flexible blade passes by the separating wheel and kicks out to a free position.

18. The paper sheet feeder in accordance with claim 12 wherein said separating wheel is rotated in a direction counter to the paper feed direction during a feed operation.

19. The paper sheet feeder in accordance with claim 8 wherein said cutout is in the upper section of said tray means.

20. The paper sheet feeder in accordance with claim 8 wherein said cutout is in both the upper and inclined sections of said tray means.