JPH0326626A - Automatic paper supply device - Google Patents

Abstract

PURPOSE:To eliminate production of wrinkles in a sheet, prevent occurrence of jam or a sheet feed failure, and transfer a sheet securely by setting the width of a friction member in the perpendicular direction to the paper supply direction larger on the downstream of paper supply. CONSTITUTION:The width of a friction member 10 in the perpendicular direction to the paper supply direction of paper supply is set larger on the downstream of paper supply. The surface where a sheet S gets in contact with the friction member 10 becomes smaller on the upstream of paper supply, and the friction force produced between the sheet S and the friction member 10 becomes smaller on the upstream of paper supply as it is farther from a nip part 7a of a roller 7 with the friction member 10. When the sheet S is part from the nip part 7a of the roller 7 with the friction member 10, therefore, the sheet is not prevented from advancing if it gets in contact with the friction member 10, and only one sheet that is in contact with the roller 7 follows the roller 7 at a close position to the nip part 7a, while the other sheets are prevented from advancing by the friction member 10. The sheet S is thus transferred one by one in order without stay.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic paper feeder installed in, for example, a copying machine or a facsimile machine. (Prior Art) Conventionally, as this type of automatic paper feeding device, there is one shown in FIG. 3, for example. In the figure, an automatic paper feeder 10
The separation section 101 of 0 is made up of a rubber friction member 103 pressed against a sponge rubber roller 102 which is rotatably installed by a pressure contact member 104, and a sheet 105 is fed between them.

At this time, the friction coefficient between the sheet 105 and the roller 102 is μ1, the friction coefficient between the sheet 105 and the friction member 103 is μ2, the friction coefficient between the sheets 105, 105 is μ,
Then, the relationship μE〉μ2〉μ3 holds true.

Multiplying these friction coefficients by the pressing force N gives the friction force generated between them. Therefore, μ1 ・N〉μ2・
N〉μ,・N. The feeding of the sheet 105 when this relationship holds will be described.

(a) When there is only one sheet, μ1・N>μ2・N, and the frictional force generated between the sheet 105 and the roller 102 is larger than the frictional force generated between the sheet 105 and the friction member 103. , the sheet 105 is driven by the roller 102 rotating in the direction of arrow a and is conveyed in the direction of arrow b.

(b) When there are two sheets, first for the lower sheet, the force is μ ・N> μ 3 ・N, and the friction force generated between the sheet 105 and the roller 102 is the friction force generated between the sheets 105 and 105. Since the force is larger than the force, the lower sheet 105 is moved by the roller 102 as described above.
The material is transported in the direction of arrow b according to the rotation of the material. At this time, a force acts on the upper seat 105 that follows the lower seat 105 due to the frictional force between the sheets. The forward movement is stopped by the frictional force generated between the member 103 and the member 103. Lower sheet 105
When the roller 102 comes into contact with the second sheet 105 after conveying the second sheet 105, the second sheet 105 is also conveyed by the rotation of the roller 102, as in the case (a) above. (C) When there are three or more sheets When the roller 102 rotates as in the case of (b) above, the bottom sheet 105 is driven by the roller 102 and conveyed. At this time, the top sheet is fastened by the friction member 103 as in the case of (b) above, but the sheets 105 other than the top and bottom sheets are held together by the frictional force between the sheets. A force acts to follow the bottom seat 105 and move forward. However, as shown in FIG.
contact the friction member 103 in order from the upper sheet at the tip, μ2 ・N>μ, ・N, so these sheets 105, . . . contact the friction member 10
It is held by 3. And the second and subsequent sheets 10
5, -... are also conveyed in the same way as the first sheet, and each sheet is conveyed one by one. (Problem to be Solved by the Invention) However, in the case of the above-mentioned prior art, μ3 cannot be changed arbitrarily because it is the coefficient of friction between sheets, so it is necessary to increase μ2 in order to make μ2>μ3. However, if the coefficient of friction between the sheet and the friction member is too large, when the sheet to be conveyed comes into contact with the friction member before the roller, the sheet will be caught by the friction member, causing a problem between the roller and the friction member. In many cases, the sheet would not be conveyed due to being pinched by the sheet, resulting in the sheet not being fed. Further, even when the sheet is fed, the sheet is caught on the friction member while being conveyed, which often causes wrinkles and jams, especially in thin sheets.

The present invention has been made to solve the problems of the prior art described above, and its purpose is to provide an automatic sheet feeding device that can reliably convey sheets without causing wrinkles in the sheets. There is a particular thing.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a rotatably installed roller and a friction member that is pressed against the roller, In an automatic sheet feeder in which only one sheet in contact with the roller is conveyed as the roller rotates, and the other sheets are conveyed one by one by being held by the friction member, the friction member It is characterized by the width in the direction perpendicular to the paper feeding direction, which is larger toward the downstream side in the paper feeding direction. (Function) In the apparatus of the present invention having the above configuration, since the width of the friction member in the direction perpendicular to the paper feeding direction is larger toward the downstream side of the paper feeding direction, the area of contact between the sheet and the friction member in the paper feeding direction The frictional force generated between the sheet and the frictional member is smaller as it moves upstream in the paper feeding direction, that is, as it moves away from the nip between the roller and the frictional member. Therefore, when the sheet is away from the nip between the roller and the friction member, the sheet will not be stopped from moving forward even if it contacts the friction member, and in the vicinity of the nip, only one sheet that is in contact with the roller will move forward. The other sheets are held in place by a friction member. As a result, the sheets to be conveyed are not caught by the friction member, and the sheets are conveyed one by one without any hitch. (Example) The present invention will be explained below based on the illustrated example. FIG. 1 is a schematic perspective view showing the configuration of a separating section of an automatic paper feeder according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing the structure of the automatic paper feeder according to the same embodiment. In FIG. 2, this automatic paper feeder 1 is provided with a preliminary conveyance section 2 and a separation section 3, and the preliminary conveyance section 2 includes a preliminary conveyance roller 4 rotatably installed in the direction of arrow a, and a preliminary conveyance roller 4 rotatably installed in the direction of arrow a. Spring 5 on conveyance roller 4
and a pressure contact member 6 that is pressed into contact with each other.

The separation unit 3 includes a roller 7 installed rotatably in the direction of arrow a, and a spring 8 attached to the roller 7. A friction member 10 is pressed by a pressing member 9. Here, the roller 7 and the friction member 10 are conventionally made of CR (chloroprene rubber), but in order to prevent the rubber from deteriorating and the friction coefficient to change when an original coated with silicone oil is used as a paper feed sheet, silicone is used. Preferably, it is made of rubber.

As shown in FIG. 1, the width of the friction member 10 in the direction perpendicular to the feeding direction of the sheet S (direction of arrow b) increases toward the downstream side in the feeding direction. For example, in FIG. 1, the width Wl of the downstream end of the friction member 10 in the sheet feeding direction. The width W2 of the upstream end and the width W3 of the intermediate portion are set such that W 1 >W3>W2 holds true.

In the automatic paper feeder 1 configured as described above, a plurality of sheets S, . . .
and is conveyed in the direction of arrow b as the preliminary conveyance roller 4 rotates.

The plurality of sheets S, . . . are first brought into contact with the friction member 10 at a position of width W2 to W3 in FIG. In the width W2 to W3, the friction member 10 has a seat S,
Since no frictional force is generated to stop the preliminary conveyance of sheets S. ... advances toward the downstream side in the sheet feeding direction while being in contact with the friction member 10, and as the width of the friction member gradually increases, the contact area between the sheet S and the friction member 10 increases, and therefore the friction generated The force also increases, and the roller 7 and friction member 1
The upper sheet S is sequentially fastened in the vicinity of the nip portion 7a with the upper sheet S. At this time, only the bottom sheet S that contacts the roller 7 in the vicinity of the nip portion 7a is moved by the roller 7 as indicated by the arrow b.
conveyed in the direction. Here, in the vicinity of the nip portion 7a, the width W2 of the friction member is
The size of W1 has been determined.

After the first sheet S is conveyed, the second sheet S comes into contact with the roller 7 near the nip portion 7a, and in the same manner as above, only the second sheet 81 is conveyed. It is transported by rollers 7. Thereafter, the sheets S are conveyed one by one by the roller 7 in the same manner.

In the automatic paper feeder 1 of the above embodiment, the friction member 10
By increasing the width toward the downstream side in the sheet feeding direction, the frictional force generated between the sheet S and the friction member 10 becomes appropriate depending on the distance from the nib portion 7a, so that the sheet The sheet S moves without being stopped by the friction member 10 until it reaches the vicinity of the nip portion 7a, and after reaching the vicinity of the nip portion 7a, the sheets S. ... are held by the friction member 10, and only the 31 sheets that come into contact with the roller 7 are driven by the roller 7 and conveyed. As a result, the sheets S, . . . are conveyed one by one by the roller 7 without being caught by the friction member 10. (Effects of the Invention) The present invention has the above-described configuration and operation, and can reliably transport the sheet without causing wrinkles in the sheet, preventing occurrence of jams and sheet non-feeding.

In addition, in the device of the present invention, the friction member is formed from one member and one material, and the frictional force can be changed only by the shape, so there is a great cost advantage in manufacturing.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing the configuration of a separating section of an automatic paper feeder according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing the structure of an automatic paper feeder according to the embodiment, and FIG. FIG. 4 is a schematic perspective view showing the configuration of a conventional automatic sheet feeding device, and FIG. 4 is an explanatory diagram showing the sheet conveyance state in the conventional example. Code 1...Automatic paper feeder 7...Roller 9...Pressure member S...Sheet description 3...Separation part 7a...Nib part 10...Friction member 71: 7-ra Figure 2

Claims (1)

[Scope of Claims] Comprising a rotatably installed roller and a friction member pressed against the roller, only one sheet of a plurality of sheets that comes into contact with the roller is conveyed according to the rotation of the roller. In an automatic sheet feeding device in which sheets are conveyed one by one while the other sheets are held by the frictional member, the width of the frictional member in a direction perpendicular to the sheet feeding direction is larger toward the downstream side of the sheet feeding direction. An automatic paper feeder characterized by: