JPS61178341A - Paper supply device - Google Patents

Abstract

PURPOSE:To separate securely even thick sheet materials from each other in overlapping transfer by providing an overlapping transfer preventing pad movable in the sheet material supplying direction against a force of an elastic member. CONSTITUTION:While two sheet materials 2a, 2b tend to pass through a gap between a paper supply roller 5 and an overlapping transfer preventing pad 15 which press and sandwich said sheet materials when thick sheet materials 2 are applied to be sent overlapping, the pad 15 is moved in the paper supplying direction by a frictional press force between two sheet materials 2a, 2b against a spring 16. When stability generated by compression of the spring 16 in the paper supply direction overcomes the frictional press force between two sheet materials 2a, 2b, the second sheet material 2b is pulled back in the opposite direction to the paper supply direction at a time together with said pad 15 and separated from the uppermost sheet material 2a. Then, only the uppermost sheet material 2a is transferred to a picture forming unit at the next stage.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a paper feeder in an image forming apparatus such as a copying machine, and more particularly, to a paper feeder equipped with a means for preventing double feeding of sheet materials. Regarding the device. (b) Conventional technology As a paper feeding method in an image forming apparatus, the machine 7M is generally unaffected by the type of sheet material being fed or the surface condition of the sheet material, so it is easy to avoid paper feeding errors and paper jams. There is a demand for a paper that can be stably fed without double feeding, etc., and without any adjustment. Conventionally, methods such as round bar, II) one-member separation method, roller separation method, or belt separation method have been put into practical use. However, paper feeding devices employing a friction member separation method are often used because of their simple structure and superior stability.

As shown in FIG. 5, the paper feeding device 1 using the frictional member separation method includes a storage body (infiltration member 3) that stores a large number of sheet materials 2 in a layered manner, and an upper end portion of the storage body 3, for example. A paper feed roller 5 made of rubber or the like is disposed close to the paper feed roller 5, and a paper feed roller 5 is fixedly mounted on the mounting base 6 and
．． It consists of a friction member such as a synthetic rubber plate and a pad 7 for preventing double feeding, which are arranged facing each other at an interval of about 1 mm. The clutch 9 is turned on, the paper feed roller 5 is rotated, and the uppermost layer of notebook material 2a of the sheet materials 2 in the storage body 3 is pressed toward the paper feed roller 5 by the spring 11 via the bottom plate 10. Due to the frictional force with the paper feed roller 5, the paper passes through the gap between the paper feed roller 5 and the double-feed prevention pad 7, and is transported to the inside of the image forming device (↑), which is not shown in the drawings. If, for some reason, the second sheet material 2b is to be fed out together with the uppermost layer sheet material 2a, the second sheet material 2b will be caught between the feeding roller 5 and the double feeding prevention pad 7. When the gap is reached, the friction with the double-feed prevention pad 7 (the friction coefficient of the paper feed roller 5 is μ3, the friction coefficient of the notebook material 2 is μ2, and the friction coefficient of the double-feed prevention pad 7 is μ3). Then, each 91KA coefficient is μm〉〉
(μ2, μm>μ2) is prevented from advancing, and only the uppermost layer sheet material 2a is properly conveyed into the image forming apparatus.

Problem to be Solved by the Invention By the way, as mentioned above, the double feeding prevention band 7 is fixed and the paper feed roller 5 is fixed.
If the relative relationship between the sheet material 2 and the double-feed prevention pad 7 is kept constant, the sheet material 2 having a predetermined thickness can be separated almost effectively. It is difficult to apply the double-feed prevention function to all sheet materials within a certain thickness range.Furthermore, due to wear of a specific part of the double-feed prevention pad 7, the paper feed roller 5 Since the gap size of only a specific part between the pad 7 and the double feed prevention pad 7 changes,
This method has the disadvantage that a suitable double-feed prevention effect cannot be expected over a long period of time.

(d) Means for Solving the Problems The present invention aims to eliminate the above-mentioned problems by using a pad for preventing double feeding made of a friction member such as rubber in the sheet feeding direction using an elastic member such as a spring. is biased in the opposite direction to the elastic member, so that the electrical transmission prevention band ζ can move in the feeding direction of the sheet materials against the elastic member during double feeding of the sheet materials. I'm waiting.

(8) Effect By employing the above means, if the uppermost sheet material of the storage body (loading member) is properly moisturized by the paper feed roller, the sheet material is thin. Even if the sheet material is thick, the sheet material should be transported to the image forming apparatus in a state in which the double-feed prevention pad does not move during transport as in the past. (In addition, in the case of exactly 1 to 7 sheet materials, the double-feed prevention pad is moved by 5 times against the elastic member.) Then, together with the top layer sheet material, the second sheet material is moved!・When the material is fed out, in the case of thin sheet material: As in the past, the second sheet material is prevented from advancing by the friction of the double-feed prevention band, and the top layer is Only the sheet is transported to the image forming apparatus. Also, when two sheets of normal thickness are fed together, the two sheets are tightly pressed between the paper feed roller and the double-feed prevention pad and try to pass through. However, at this time, the ffl feed prevention pad is moved in the paper feeding direction against the elastic member due to the pressure contact force, and when the restoring force due to the compression of the spring overcomes the pressure contact force between the two sheet materials, the double feed occurs. When the prevention pad is returned to its original state, the second sheet material is separated from the uppermost sheet material at once, and only the uppermost H sorting material is conveyed to the image forming apparatus.

Furthermore, when thick sheets are fed in duplicate, the two sheets are strongly pressed between the paper feed roller and the double-feed prevention pad, and the double-feed prevention pad is pressed against the spring by an amount commensurate with the pressing force. When the double-feed prevention band returns, the second sheet material is separated by a stronger separating force, and from then on, only the top 15 sheet materials are transported to the image forming apparatus. In addition, by moving the double-feed prevention pad as described above, the wear of the double-feed prevention pad is not localized to a specific portion, the wear is evened out, and the progression of wear is delayed.

(f) Examples Now, examples embodying the present invention will be explained. Note that the same parts as those in the conventional example shown in FIG. 5 will be described using the same reference numerals.

As shown in FIG.
It has a storage body 3 that stores and stores the above-mentioned items in layers.
One member 2 is applied with a predetermined pressing force to a paper feed roller 5 disposed close to the upper end of the storage body 3 by a spring 11 disposed at the bottom of the storage body 3 via the bottom Fj, 10. (I want to be touched) The paper feed roller 5 is made of a material with a fairly large coefficient of friction, such as sponge rubber, and rotational force is transmitted by a clutch 9 that is turned on in response to a paper feed command signal. , rotates in the direction of arrow A in the figure. Adjacent to the storage body 3, a double feeding prevention means 13 having a holder 12 fixed to a fixed part such as the main body of an image forming apparatus (not shown) is provided below the paper feed roller 5.
Inside the holder 12, a flat electric transmission prevention pad 15 made of a friction member having a relatively large friction coefficient such as synthetic rubber is provided.
is urged by a spring 16 in the opposite direction to the paper feeding direction, and is guided within the holder 12 so that it can move in the directions of arrows B and C in the figure, that is, in a direction parallel to the paper feeding direction, and furthermore, the double feeding The prevention pad 15 is housed so close that the upper surface thereof does not come into contact with the paper feed roller 5. The friction coefficients of the paper feed roller 5 and the like have the relationship described above, and the holder 12 is configured such that it can be finely adjusted by an appropriate mechanism so as to be able to move forward and backward with respect to the paper feed roller 5 direction or the paper feeding direction. may be configured.

Since this embodiment has the above-described configuration, when the paper feed command signal is issued, the clutch 9 is turned on and the paper feed roller 5 is rotated, so that the sheet material 2a at the top of the storage body 3 is normally fed. Even if the sheet material 2a is a thin sheet material or a (more normal thickness) sheet material, the sheet material 1-2a is separated by the paper feed roller. It is conveyed to the image forming apparatus by the frictional force of 5. In this case, there is almost no movement of the electrical transmission prevention pad 15 due to the conveyance of the sheet material 2a. In the above case, if thick No;・Ei is applied, the top layer
, paper feed roller 5 and double feeding method 1 depending on the thickness of the paper 2ai
): The sheet is passed through while being held somewhat strongly between the paper pads 15, but at that time, the frictional force between the sheet material 2a and the sheet member 28 is greater than the frictional force between the sheet material 2a and the double-feed prevention pad 15. Although the double feeding prevention pad 15 is moved slightly in the paper feeding direction against the spring, the sheet member 2
The paper a is normally conveyed to the image forming apparatus by the rotation of the paper feed roller 5.

Then, along with the top layer sheet member 2a, the second sheet)
When the material 2b is fed out, if a thin sheet material 2 is used, the second sheet material 2b is between the feeding roller 5 and the double feeding prevention pad 15. When reaching the point 19, the electrical transmission on the top layer 19 is blocked by frictional contact with the double feeding prevention band 15, and the uppermost sheet material 2
Only the sheet 8 is properly conveyed to the image forming apparatus 5 by the conveying action caused by the friction of the sheet feeding roller 5. In addition, when sheet materials 2 of normal thickness are used, the two sheet materials 2a and 2b that are about to be double-fed are placed between the paper feed roller 5 and the double-feed prevention pad 16. When the sheet material 2a and 2b try to pass through the gap while being tightly pressed together, the double feeding prevention pad 15 resists the spring 16 due to the g friction contact force between the two sheet materials 2a and 2b, and the double feeding prevention pad 15 moves in the feeding direction. When the return force generated by the compression of the spring 16 in the sheet feeding direction overcomes the friction pressure between the two sheet materials 2a and 2b, the second sheet material 2b1. The sheet material 2A is pulled back together with the Ti transport prevention pad 15 in a direction opposite to the paper feeding direction and separated from the uppermost sheet material 2a, and then only the uppermost sheet material 2a is conveyed to the image forming apparatus. Furthermore, when a thick seam member 2 is applied,
It operates in the same way as when double feeding sheets of normal thickness, but the compression of the spring 16 becomes stronger in proportion to the thickness, and based on this, the second sheet material 2b is separated. This is carried out more forcefully, and in this case as well, only the uppermost layer sheet material 2a is suitably conveyed to the next stage image forming apparatus.

That is, the double-feed prevention pad 15 moves in the paper feeding direction due to the resistance of the sheet material 2b, and as a reaction, the spring 1
It receives a drag force of 6. As a result, the sheet material 2b is
Due to the frictional force of the pad 15 and the drag force of the spring 16, the pad 15 receives a drag force (frictional force) that tries to return to its original state, and separation is ensured.

As described above, by moving the double-feed prevention pad 15 during operation according to the thickness of the sheet material 2, the sliding contact position of the double-feed prevention pad 15 with the sheet material 2 is unevenly distributed in a specific part. Due to this, the double feed prevention pad 15
wear will be averaged out, and the progress of wear will be slowed down as a whole.

In addition, as shown in FIG. 2, the pad 15 for preventing double feeding is
The surface facing the paper feed roller 5 may be formed into a tapered surface 15a so that it becomes thicker in the paper feed direction.

As a result, as shown by the chain line, when the pad 15' is moved by the sheet material 2 in the paper feeding direction against the spring 16, the tapered surface 15a deforms and the sheet material 2 is deflected upward, and the paper feeding roller The contact angle a (therefore, the contact area) between the sheet material 2 and the sheet material 2 is increased, and separation is performed more reliably.

As shown in Figure 3, press the holder 12 with the pressing spring 2.
0, the double feed prevention pad 15 is supported by the paper feed roller 5.
It may be constructed so that it comes into pressure contact with 1. ).

With this, see! - Regardless of the thickness of the material 2, it is possible to press the sheet material 2 with the roller 5 using the double-feed prevention pad 15, thereby making it possible to more effectively separate the sheet material 2.

Furthermore, as shown in FIG. 4, the double feeding prevention pad 15 may be directly supported by the flexible member 21.

In this structure, the flexible member 21 is bent and applies a large separation frictional force to the sheet material due to the movement of the pawl/gutter 15 in the paper feeding direction as the sheet material 2 passes. As a result, the holder 12
is not required, resulting in an extremely simple configuration.

(G) As described in detail, according to the present invention, the double-feed prevention pad 15 made of a friction member is configured to be movable in the paper feeding direction, and the elastic members 16 and 21 are interposed between the pads 15 for preventing double feeding. When the sheet material 2 is double-feeded, the double-feed prevention pad 15 is connected to the elastic member 16.
．． 21, so that it can be moved in the feeding direction of the sheet material 2, so it can be used not only when a thin sheet material 2 is used, but also when a thick sheet material 2 is used. is carried out appropriately, and double feeding of the sheet material 2 to the image forming apparatus is reliably prevented. Furthermore, even if the double-feed prevention pad 15 is rubbed, the wear is evened out over almost the entire surface of the double-feed prevention pad 15, so the progress of wear is delayed and a suitable double-feed prevention method is achieved. The action takes place over a long period of time.

Furthermore, if the pad 15 for preventing double feeding is configured so that it can move forward and backward with respect to the paper feed roller 5 and/or the stacking member 3 and adjust the yA slightly, it is possible to change the thickness range of the sheet material 2. In addition, wear of the double-feed prevention pad 15 can be compensated for, thereby making it possible to use the double-feed prevention pad 15 for a longer period of time. In addition, when the double-feed prevention pad 15 is oriented in the paper feeding direction, the surface facing the paper feed roller 5 is aligned with the taper 15a so that it becomes thicker, and as the double-feed prevention pad 15 moves, the material 2 The contact area between the paper feed roller 5 and the paper feed roller 5 is expanded, and separation can be performed more reliably.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a paper feeding device according to the present invention, FIGS. 2 and 2 are enlarged views showing a partially modified double-feed prevention pad, and FIGS. 3 and 4 are side sectional views showing other embodiments. 1 and 2 are side sectional views of a conventional paper feeding device.
2...Sheet material, 3. Loading member (storage body)
, 5...Paper feed roller, 12...Holder,
15. Pad for preventing double feeding, 16. Elastic member (spring), 21. Elastic member (flexible member).

Claims (2)

[Claims] (1) A paper feed roller that separates and conveys a large number of sheets stacked and stored in layers on a stacking member one by one from the stacking member, and a friction member disposed opposite to the paper feed roller. In a paper feeding device equipped with a double-feed prevention pad, the double-feed prevention pad is disposed facing the paper feed roller, is configured to be movable in the paper feeding direction, and has an elastic member interposed between the double-feed prevention pad and the sheet feed roller. A sheet feeding device characterized in that the double feeding prevention pad is configured to move in the feeding direction of the sheet materials against the elastic member when sheets are fed in duplicate. (2) The paper feeding device according to claim 1, wherein the double feeding prevention pad is configured to be finely adjusted to move forward and backward relative to the paper feeding roller and/or the stacking member.