JPH02295832A - Automatic paper sheet feeding device - Google Patents

Abstract

PURPOSE:To prevent double feed of paper sheets certainly by furnishing a spring to energize an arm so that a separator roller rotates in the opposite direction to sheet feed, and providing a stopper to hinder rotation of this arm so that the separator roller is restricted from rotation in the sheet feeding direction. CONSTITUTION:While a first original text sheet is being fed, a separator roller 11 is at a standstill in a place where an arm 13 is in contact with a stopper 17, and a tensile force due to a spring 14 is applied to this arm 13. While the first original is being fed, the second original and even thereafter may be fed to between an aux. feed roller 10 and a separator roller 11 because of poor separating motion of a separator piece 6. Because friction force between the first and second originals is small, the transport force applied by a feed roller 5 to the second original is small, to allow the tensile force of the spring 14 to rotate the separator roller 11 in the direction opposite to the sheet feeding, which pushes back the second original and thereafter eventually to accomplish prevention of double feed of sheets.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic paper feeder used in facsimiles, copying machines, and the like.

Conventional technology Conventionally, in order to separate and feed papers such as originals and recording papers one by one, a paper feed roller that rotates in the paper feeding direction and a rubber plate with a high friction coefficient that presses the paper against this paper feed roller are used. An automatic paper feeding device is known that includes a separate piece such as (see, for example, Japanese Utility Model Application Publication No. 137737/1983). Also known are those in which a separation roller is used in place of the separation piece (see, for example, Japanese Utility Model Applications No. 58-34134 and Japanese Utility Model Application No. 62-203150). These automatic paper feeders utilize the small coefficient of friction between sheets to prevent double feeding of sheets. That is, when two sheets of paper are simultaneously fed between the paper feed roller and the separation piece or separation roller, the paper that has come into contact with the separation piece or separation roller is restrained by the separation piece or the separation roller, and the paper feed Only the paper that has come into contact with the roller is fed by the paper feed roller, so that the paper is separated and fed one by one.

In addition, automatic paper feeding devices are also known that use a reversing roller that is normally rotated in the opposite direction to the paper feeding direction via a torque limiter or the like instead of the separation roller (for example, (See Publication No. 23242).

When multiple sheets of paper are caught between the paper feed roller and the paper feed roller, this reversing roller not only restricts the paper from being fed other than the paper that is in contact with the paper feed roller, but also returns the paper to its original position. It also has the effect of pushing back the sheets, ensuring that the required paper is separated.

Problems to be Solved by the Invention However, all of the conventional automatic paper feeders having the above configurations have had problems. That is, in the case of a type that uses a separation piece or a separation roller, the contact pressure between the separation piece or separation roller and the paper feed roller has a serious effect on preventing double feeding, and this adjustment is difficult. If the contact pressure is too low, double feeding of sheets cannot be prevented and two or three sheets of paper may be fed at the same time, whereas if the contact pressure is too high, it may not be possible to feed the sheets.

Further, when a reversing roller is used, a drive mechanism including a torque limiter is required, resulting in a problem that the device configuration becomes complicated.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an automatic paper feeder with a simple structure that can separate sheets one by one and feed them satisfactorily.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention includes a paper feed roller that feeds paper in the paper feeding direction, and a paper feed roller that is arranged to press the paper against the paper feed roller to prevent double feeding of documents. In the automatic paper feeder having a separation piece that separates the sheet, further, an auxiliary paper feed roller is rotatably disposed on the same axis as the paper feed roller, and the document conveyed by the paper feed roller is transferred to the auxiliary paper feed roller. A separation roller is arranged so as to be pressed against the separation roller, and this separation roller is held so as to rotate integrally with the holding shaft.
and an arm is attached to one end of the holding shaft, and the arm is urged by a spring so that the separation roller fixed to the holding shaft rotates in a direction opposite to the paper feeding direction, and This device has a structure in which a stopper is provided to prevent rotation of the arm so as to restrict rotation in the paper direction.

Operation According to the above-described structure, the present invention allows the paper to be fed to be fed downstream through the space between the paper feed roller and the separation piece, and during this time, double feeding is prevented by the separation piece. Also, while a sheet of paper is being fed by the paper feed roller, the paper passes between the auxiliary paper feed roller and the separation roller, so the separation roller is driven in the paper feeding direction by the paper, and the arm is It is stopped at a position where it is restrained by a stopper. By the way, double feeding of sheets may not be prevented by simply using the paper feed roller and the separation piece. In that case, for example, two sheets of paper try to pass between the paper feed roller and the separation piece, but the two sheets of paper are simultaneously fed between the auxiliary paper feed roller and the separation roller. At this time, the separation roller cannot rotate in the paper feeding direction, and is urged by a spring connected to the arm to rotate in the opposite direction to the paper feeding direction, so the paper on the side that contacts the separation roller Further, the urging force of the spring causes the paper to be reversed and pushed back to its original position. In this way, double feeding of sheets can be reliably prevented.

Embodiment FIG. 1 is a perspective view schematically showing the main parts of an embodiment in which the present invention is applied to an automatic document feeder in a facsimile, and FIGS. 2, 3, and 4 respectively show the above embodiment. It is a schematic sectional view explaining operation.

In Figures 1 to 4, 1 is a document to be fed, 2 is a document table on which the document 1 is set, 3 is a document guide provided at the lower end of the document table 2, and 4 is a drive device. (not shown) a paper feed roller shaft rotated in the paper feed direction;
is a paper feed roller fixed to the paper feed roller shaft. The paper feed roller 5 is composed of a relatively soft rubber roller section 5A at the center and relatively hard rubber roller sections 5B on both sides thereof. 6 is a rubber roller portion 5A at the center of the paper feed row 25
A separating piece such as a rubber plate is provided to be pressed with an appropriate pressure on the paper feed roller 5.
The pinch roller 8 is a pinch roller shaft that rotatably holds the pinch roller 7. This pinch roller 7 is arranged so as to contact the paper feed roller 5 downstream of the contact position of the separation piece 6 with the paper feed roller 5 .

Reference numeral 10 denotes an auxiliary paper feed roller rotatably held on the paper feed roller shaft 4. Reference numeral 11 denotes a separation roller arranged to press the document conveyed by the paper feed roller 5 against the auxiliary paper feed roller 10; 12 a holding shaft that holds the separation roller 11 and rotates together with the separation roller 11; 13 is an arm fixed to one end of the holding shaft 12; 14 is a spring connected to the arm 13; 15 is an adjustment screw that fixes one end of the spring 14; 16 is a frame that holds the adjustment screw 15.

The spring 14 biases the arm 13 in the direction of arrow A, that is, so that the separation roller 11 rotates in the opposite direction to the paper feeding direction (direction of arrow B). Reference numeral 17 denotes a stopper that prevents the arm 13 from rotating in a direction opposite to the arrow A, that is, to prevent the separation roller 11 from rotating in the sheet feeding direction. As can be clearly seen from FIG. 2, the contact position of the separation roller 11 with the auxiliary paper feed roller 10 is approximately the same as the contact position between the paper feed roller 5 and the separation piece 6, and the contact position between the paper feed roller 5 and the pinch roller 7. The location was also selected to be upstream. Reference numeral 18 denotes a document sensor that detects that the document 2 is set on the document table 1.

The operation of the automatic paper feeder configured as above will be described below.

In FIG. 2, when the original 1 is set at a predetermined position on the original platen 2, the original sensor 18 detects it, and then when the transmission operation starts, the paper feed roller shaft 4 and the paper feed roller 5 fixed thereto rotates in the direction of arrow C. As a result, the original 1 on the original platen 2 is drawn between the paper feed roller 5 and the separation piece 6, and the originals other than the lowest layer that contacted the paper feed roller 5 are removed by the separation piece 6. The paper feed row 25 sends only the first document in the lowermost layer downstream.

After passing through the contact position between the paper feed roller 5 and the separation piece 6, this document is sandwiched between the paper feed roller 5 and the pinch roller 7, and is fed to a downstream document reading position at a predetermined speed.

On the other hand, while the first document is drawn between the paper feed roller 5 and the separation piece 6 and conveyed downstream, the document passes between the auxiliary paper feed roller 10 and the separation roller 11, Due to the frictional force against the original, the auxiliary paper feed roller 10 and separation roller 11 rotate in the paper feeding direction shown by arrows B and C. Since the separation roller 11 rotates in the direction of arrow B, the arm 13 fixed to the holding shaft 12 holding the separation roller 11 also rotates in the direction of arrow B against the tension of the spring 14 in the direction of arrow B. As shown in the figure, the separation roller 11 stops when it hits the stopper 17, and at the same time, the rotation of the separation roller 11 also stops.

After that, the original is transferred to the auxiliary paper feed roller 10 and the separation roller 1.
1, the separating roller 11 only slides on the document but does not rotate. Here, the force of the spring 14 is such that when one document is moved by being given a conveying force by the paper feed roller 5 and the separation piece 6, the force between the document and the separation roller 1 is
When a rotational force is applied to the separation row 211 by the frictional force between the arm 13 and the stopper 17, the arm 13 is allowed to rotate in the direction of arrow B until it almost hits the stopper 17; It is preferable that the rotational force of the roller 11 is set to approximately balance the tensile force of the spring 14.

While the first document is being fed, the separation row 211 stops at the position where the arm 13 contacts the stopper 17 as described above, and the arm 13 is subjected to tension in the direction of the arrow by the spring 14. is working. While the first document is being fed in this way, the separating action by the separation piece 6 is incomplete, and at the same time, the second and subsequent documents are caught between the auxiliary paper feed roller 10 and the separation roller 11. It may happen. However, since the frictional force between the first and second originals is small,
The conveyance force applied by the paper feed row 25 to the second document is small;
Therefore, the separation roller 11 is rotated in the opposite direction to the paper feeding direction (direction of arrow B) by the tension of the spring 14, pushing back the second and subsequent documents, and preventing the second and subsequent documents from being fed at the same time. do. In this way, the documents are reliably separated and only one document is fed.

Incidentally, at the start of paper feeding, that is, when the arm 13 is in the position shown in FIG. 2, two documents may be simultaneously fed between the auxiliary paper feeding roller 10 and the separation roller 11. In this case as well, the conveyance force applied by the paper feed row 25 to the second document is small, so that the document can hardly rotate the separation roller 11 in the direction of arrow B against the tensile υ force of the spring 14. First, the documents are restrained by the separation roller 11, and double feeding of documents is prevented.

When the first document passes the paper feed roller 5 and is finished being sent, the rotation of the paper feed roller 5 stops, and the fourth document passes through the paper feed roller 5.
As shown in the figure, the tensile force of the spring 14 causes the arm 13 to
returns to its original position. The operation for the second and subsequent sheets is the same as the operation for the first sheet.

In the above embodiment, the arm 13 is provided only at one end of the holding shaft 12, but it goes without saying that it may be provided at both ends.

Effects of the Invention As is clear from the above description, the present invention has an auxiliary paper feed roller rotatably disposed on the same axis as the paper feed roller, and a separation roller arranged so as to press against the auxiliary paper feed roller. Further, an arm is attached to one end of the holding shaft to which the separation roller is attached, and a spring is connected to the arm to urge the separation roller to rotate in a direction opposite to the paper feeding direction, and A stopper is provided to prevent the rotation of the arm so as to restrict the rotation of the separation roller in the paper feeding direction, so when the paper feed roller feeds paper, the paper does not pass between the auxiliary paper feed roller and the separation roller. When there is only one sheet of paper, the separation roller is rotated by the paper in the paper feeding direction against the biasing force of the spring, and is stopped at a position where the arm is restrained by the stopper. When paper is fed, the separation roller rotates in the opposite direction to the paper feeding direction due to the biasing force of the spring, pushing the paper on the separation roller side back to its original position, reliably preventing double feeding of paper. It has the effect of being able to Furthermore, although the separation roller of the present invention is configured to be able to rotate in the opposite direction to the conveyance direction, the structure is simple because it does not require a drive mechanism equipped with a torque limiter as used in conventional reversing rollers. It also has this effect.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing the main parts of an embodiment in which the present invention is applied to an automatic document feeder in a facsimile, and FIGS. 2, 3, and 4 respectively illustrate the operation of the above embodiment. It is a schematic sectional view for explanation. 1... Original, 2... Original table, 3... Original guide,
4...Paper feed roller shaft, 5...Paper feed roller, 6...
Separation piece, 7... Pinch roller, 10... Auxiliary paper feed roller, 11° Separation roller, 12... Holding shaft, 13
...Arm, 14...Spring, 17...Stopper

Claims (1)

[Claims] A paper feed roller that feeds the paper in the paper feeding direction, a separation piece that is arranged to press the paper against the paper feed roller and prevent double feeding of paper, and a separation piece that is rotatably arranged on the same axis as the paper feed roller. a separation roller arranged to press the paper conveyed by the paper feed roller against the auxiliary paper feed roller; and a separation roller that holds the separation roller;
A holding shaft that rotates together with the separation roller, an arm fixed to the holding shaft, a spring that biases this arm so that the separation roller rotates in a direction opposite to the paper feeding direction, and a feeding shaft for the separation roller. An automatic paper feeder having a stopper that prevents the rotation of an arm so as to restrict the rotation of the paper direction.