JPS60183445A - Sheet feeder for picture image forming apparatus - Google Patents

Abstract

PURPOSE:To enable smooth separated feeding of sheet by slightly inclining the inlet of sheet or a wedge-shaped gap in a friction belt separation feeder and bringing the tip to such depth as reaching to the central portion in the carrying direction of belt. CONSTITUTION:In a feeder comprised of a pair of vertical endless belts 4, 5 where the belt 4 is rotated in the carrying direction of sheet P while the belt 5 is rotated in reverse direction to carry the sheet P pulled between said belts 4, 5 while separating one by one, a sheet separation interval A made of slightly inclined wedge-shaped gap S having the tip reaching to the central portion in the carrying direction of belt is formed. The interval between the tip of said gap S and the outlet of sheet overlapped with narrow belts arranged up and down is employed as the sheet carrying interval B. Consequently, sheet can be carried smoothly while being separated irrespective of the thickness and the hardness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an automatic sheet document system for automatically feeding stacked sheet documents one by one to a document illumination section or a reading section in an electronic copying machine, facsimile machine, image reading device, etc. The present invention relates to a feeding device or an automatic feeding device for copying paper or printing paper in an electronic copying machine or a printing machine.

Conventionally, this type of single-sheet separation and feeding apparatus includes a friction pad type in which a separation pad 2 is brought into contact with a transport roller 1 that rotates in the sheet transport direction as shown in FIG. 1, and a friction pad type that rotates in the sheet transport direction as shown in FIG. A friction roller type in which a separation roller 3 that stops or reverses is in contact with a conveyance roller l, and a pair of upper and lower endless belts 4 and 5 in contact with Y in FIG.
There is a friction belt type in which one belt 4 is rotated in the sheet conveyance direction and the other belt 5 is stopped or rotated in the opposite direction.

However, on the entrance side of the sheet, between roller L and pad 2 (example in Figure 1), lower rollers L and 3 (example in Figure 2), and ends of upper and lower belts 4 and 5 (example in Figure 3). Since the wedge-shaped gap S that is formed has a steep slope, that is, the gap S is shallow, the sheet separation operation performed one by one following the slope of the wedge is uncertain.

Further, in the examples shown in FIGS. 1 and 2, there is a small nip portion following the sheet separating portion, that is, a contact portion for feeding the sheets, so that overlapping feeding is likely to occur. If the clamping force at the nip section is increased to prevent such overlapping feeding, sheets such as hard paper, paper with curls, e.g. curled paper may have difficulty entering the nip section and may not be fed. In the figure, 6 is a conveyance guide plate, 7 and 8 are a pair of feed rollers for further feeding the sheets drawn into the machine by the feeding device to the subsequent processing section, and 9 is a -L of stacked sheets P. In the example shown in FIG. 1, the transport roller 1 is in direct contact with the surface of the laminated sheet [P] and also serves as a drawing roller.

1-Wiring 3 The belts 4 and 5 of the friction belt type separating and feeding device shown in the diagram are either wide belts or multiple narrow belts arranged in parallel. In this case, upper and lower narrow belts are arranged alternately and the upper and lower belts are overlapped as means for reinforcing conveyance clamping force.

However, the amount of overlap between the upper and lower belts affects the entrance side of the sheet, that is, the wedge-shaped gap, making it unstable to enter the sheet, which may make the separation and feeding of individual sheets unreliable.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in conventional automatic sheet separation and feeding devices, and to provide a device that can smoothly separate and feed sheets regardless of their thickness and stiffness.

The sheet feeding device of the present invention has a basic configuration of a friction belt two-separation feeding device shown in Fig. 3 of L distribution, especially a feeding device in which ten F belts are overlapped using a narrow belt. That is, it consists of a pair of endless belts 4 and 5, each of which consists of a plurality of narrow belts arranged in parallel (as shown in Figure 6), and one of the upper and lower belts 4
is rotated in the conveyance direction of the sheet P, and the other belt 5 is rotated to a stop or in the opposite direction to the sheet conveyance direction,
In the feeding device configured to separate and convey the sheets drawn between the upper and lower belts 4 and 5 one by one, the leading end reaches approximately the center of the belts 4 and 5 in the conveying direction on the sheet inlet side. Sheet separation section A consisting of a wedge-shaped gap S with a gentle slope
A section B from the tip of the wedge-shaped gap S to the exit of the sheet is characterized in that the narrow belts 4 and 5 alternately arranged above and below overlap to form a sheet conveying section.

4 and 5 show each embodiment of the present invention. In the example shown in FIG. 4, the belt 4Φ5 is arranged so that the entrance of the wedge-shaped gap S is located at the top side of the stacked sheets P. and is equipped with a pull-in roller 9. The conveyor belt 4 is supported by pulleys 10-11 with equal diameters at the front and rear, and the separation belt 5 has a small diameter at the front.
The back is supported by pulleys 12 and 13 with large diameters, and by gradually overlapping the tension side rear half of the separation belt 5 with the conveyor belt 4, a wedge-shaped gap S with a gentle slope is formed in the front half. .

In the example shown in FIG. 5, the conveyor belt 4 is extended above the sea) P,
The front end of the belt 4 is brought into contact with the sheet and doubles as a pull-in roller, so the number of parts can be reduced. Note that instead of drawing the belt 4 into contact with the sheet, a roller exclusively for drawing the belt 4 may be provided coaxially with the front pulley lO of the belt 4 -L.

FIG. 6 shows a longitudinal sectional front view of the wedge-shaped gap, ie, the sheet separation section A, in each of the above embodiments, and FIG. 7 shows a longitudinal sectional front view of the overlap section, ie, the sheet conveying section B.

Several sheets are fed into the wedge-shaped gap S by the rotation of the conveyor belt 4 (in the example shown in FIG. 4, the pull-in roller 9 also rotates at the same time). The friction coefficient between the conveyor belt 4 and the sheet P is set to be larger than the friction coefficient between the separation belt 5 and the sheet P.

The edge of the sheet that has entered the wedge-shaped gap S is formed by the interaction of the difference in the rotation direction of the upper and lower belts 4 and 5, the difference in the coefficient of friction with the sheet, and the gentle slope of the wedge shape.
As shown in FIG. 8, the paper is separated little by little with a slight shift, and gradually enters the overlapping portion of the belts 4 and 5, where it is separated into strips and is conveyed while being held between the belts 4 and 5. Even if the two sheets are not separated properly and sent overlapping,
When the overlapping amount of the upper and lower belts 4-5 reaches the maximum position, they are completely fed as one sheet.

The sheet coming out from the rear end of the bell]・4Φ5 is further nipped by feed rollers 7 and 8 and conveyed to the processing section. Hard sheet - A stiff sheet is mostly inside the wedge-shaped gap S,
Soft Sea I: A weak sheet is separated near the position of maximum overlap.

In all of the embodiments described in 1-, the stacked sheets are taken from -L, but it is of course possible to implement the method in which the stacked sheets are taken from the bottom one.

In the sheet feeding device in the image forming apparatus of the present invention, as shown in L, the entrance of the sheet in the friction belt type separation feeding device, that is, the wedge-shaped gap S is gently inclined, and the tip thereof is connected to the belts 4 and 5. Since the depth is set to reach approximately the center in the conveyance direction, the sheet separation section A is long and the sheets can be separated easily and smoothly.Furthermore, the conveyance section B that follows is also long, and in that section B, the area below -F is long. Belt 4/5
Since the sheets are overlapped, the sheets are completely separated and 1
This has the effect of quickly and reliably transporting sheets one by one.

[Brief explanation of the drawing]

1, 2, and 3 are side views illustrating a conventional sheet feeding device, FIG. 4 is a side view of an embodiment of the sheet feeding device of the present invention, and FIG. 5 is a side view of an embodiment of the sheet feeding device of the present invention. A side view of another embodiment,
FIG. 6 is a longitudinal sectional front view of the sheet separation section, FIG. 7 is a longitudinal sectional front view of the sheet conveyance section, and FIG. 8 is an enlarged side view illustrating the sheet separation action of the apparatus of the present invention. 4 is a conveyor belt, 5 is a separation belt, 9 is a drawing roller,
IO to 13 are pulleys, A is a sheet separation section, B is a sheet conveyance section, and P is a sheet. JP-A-Sho GO-183445 (4)

Claims (1)

[Claims] (1) Consists of a pair of upper and lower endless belts; one belt is rotated in the sheet conveyance direction, and the other belt is stopped or rotated in the opposite direction to the sheet conveyance direction, and pulled between the upper and lower belts. In a feeding device configured to separate and convey sheets one by one, a sheet separation section is formed on the inlet side of the sheet, the sheet separation section consisting of a gently sloped wedge-shaped gap whose tip reaches approximately the center of the belt in the conveying direction, A sheet feeding device for an image forming apparatus, characterized in that a sheet conveying section is formed by overlapping narrow belts alternately arranged vertically and vertically from the tip of the wedge-shaped gap to the sheet exit.