JP2011178514A - Separating and feeding device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separating and feeding device capable of stably separating and feeding paper by a friction pad system without double feed and non-feed, and to provide an image forming device. <P>SOLUTION: A force sensor 34 for detecting a pressing force P2 between a paper feed roller 40A and uppermost paper S1 at a pressing part T1 (on which the uppermost paper S11 pressed against the paper fed roller 40A is pressed) is disposed at the paper feed roller 40A side of the pressing part T1 which is pressed against the paper feed roller 40A by a pad means 31. A calculator 52 determines whether the pressing force P2 is appropriate or not, and if not appropriate, transmits a signal for moving a pad pressing member moving means 35 to the pad pressing member moving means 35 to make the pressing force appropriate. The pad pressing member moving member 35 moves the pad pressing member 32 based on the signal transmitted from the calculator 52 to adjust the pressing force P1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a separation sheet feeding device that is used in a sheet feeding mechanism of an image forming apparatus such as a copying machine or a printer and separates and conveys a bundle of sheets one by one so that sheets are not multi-fed, and in particular, a friction pad type. The present invention relates to a separation sheet feeding apparatus that performs separation sheet feeding and an image forming apparatus including the same.

  In a paper feeding device used in a paper feeding unit of a machine having a paper transport mechanism of an image forming apparatus such as a copying machine or a printer, a separation paper feeding device that performs separation paper feeding by a friction pad method is known (for example, patents). Reference 1). An example of a conventional friction pad type separation sheet feeding device will be described with reference to FIGS. FIG. 17 is a cross-sectional view showing a schematic configuration of a conventional separation paper feeder. FIG. 18 is a side view showing a paper feeding state by the separation paper feeding device shown in FIG.

  In the separation sheet feeding device 1 of FIG. 17, the sheet feeding roller 40 is rotatably supported on the apparatus main body side (not shown) such as a copying machine by a rotating shaft 41, and an arrow A is driven by a driving motor (not shown). It is rotationally driven in the direction. A friction pad 30 that presses and urges the sheet feeding roller 40 is supported on an upper portion of the pad means 31. The friction pad 30 is mainly a friction member such as cork. The pad means 31 is connected to a paper feed cassette (not shown) by a connecting device 60. The pad means 31 and the connecting device 60 are coated with a lubricant or the like between them, and are connected by a fastening part or the like at the connecting portion 61. A pad urging member such as a coil spring supported by a pad urging member supporting means 62 is provided between the pad means 31 and the connecting device 60 in order to urge the pad means 31 against the paper feed roller 40. 32 is inserted, and an urging force P <b> 1 by the pad means 31 as a pressing force is generated by the elastic force of the pad urging member 32.

  Further, in the sheet feeding cassette (not shown), there is a bottom plate 45 that can be moved up and down and pressed and pressed by a bottom plate biasing member 46 such as a coil spring supported by a bottom plate biasing member support means 47. On top of 45, a sheet bundle S0 is stacked. The uppermost sheet S1 is pressed against the paper feed roller 40 by the urging force Q1 by the bottom plate 45 pressed and urged by the bottom plate urging member 46. At this time, when the paper feed roller 40 rotates in the direction of arrow A, the uppermost sheet S1 receives frictional force from the paper feed roller 40 and enters between the paper feed roller 40 and the friction pad 30. At this time, the conveyance force obtained by the uppermost sheet S1 pressed against the sheet feeding roller 40 is F1, the resistance force when the uppermost sheet S1 enters between the sheet feeding roller 40 and the friction pad 30 is F2, and the friction pad 30. When the friction coefficient between the uppermost sheets S1 is μ1 and the urging force by the pad means 31 is P1, if the relations F1> F2 and F1> μ1 · P1 are satisfied, the uppermost sheet S1 is fed. It is possible to enter between the roller 40 and the friction pad 30. When a plurality of sheets enter between the sheet feeding roller 40 and the friction pad 30 at the same time, the sheets are separated due to the difference in frictional force due to the difference in friction coefficient, and only one sheet is fed to the main unit. . For example, when the friction coefficient is μ2 between the paper feed roller 40 and the uppermost sheet S1 and μ3 between the uppermost sheet S1 and the sheet bundle S0, P1 is sufficiently larger than the reaction force due to deformation of the uppermost sheet S1. If the urging force between the paper feeding roller 40 and the uppermost paper S1 is P2, and P1 = P2, then if the relationship of μ2> μ1> μ3 is established, the paper feeding roller 40—the uppermost paper S1. The frictional force acting between them is maximized, and only one of the uppermost sheets S1 is separated and fed.

  In the friction pad type separation feeder as described above, each friction coefficient varies greatly depending on the environment, changes with time, paper type, etc., and therefore, a technical problem that an appropriate urging force of the pad cannot be uniquely determined. There is. For this problem, for example, solutions such as Patent Document 2 and Patent Document 3 have been proposed.

  In Patent Document 2, a force sensor 33 is provided between the friction pad 30 and the support portion 31a of the pad means 31 in order to perform stable paper feeding without double feeding and non-feeding of the paper. It has been proposed to adjust the urging force P1 by changing the position of the pad urging member support portion 62 in accordance with the urging force P1 by the pad means 31 detected by.

  In Patent Document 3, a step-shaped recess is formed at a position of the bottom plate 45 facing the paper feed roller 40, and a load cell is disposed in the recess, and the urging force Q1 by the bottom plate 2 is detected by the load cell. On the basis of this detection result, it has been proposed to move the position of the bottom plate urging member support portion 47 and adjust the urging force Q1 to perform stable paper feeding without double feeding and non-feeding of paper. .

  However, in the ones described in Patent Documents 2 and 3, since the force sensors are disposed on the pad means 31 and the bottom plate 45, respectively, the urging force of the uppermost sheet S1 with respect to the sheet feeding roller 40 is not properly detected. As a result, there is a problem in that the urging force by the pad urging member 32 and the bottom plate urging member 46 is not properly adjusted, and stable paper feeding without double feeding and non-feeding of paper cannot be performed. . For example, when the paper is stiff due to a large paper thickness, the top paper S1 is deformed so as to be separated from the paper feed roller 40 due to the paper stiff, and a problem that a sufficient urging force cannot be secured is incurred. That is, as shown in FIG. 18, the uppermost sheet S1 is conveyed while being bent by the sheet feed roller 40, the bottom plate 45, and the friction pad 30. When the uppermost sheet S1 is thick and stiff, the bottom plate 45 and the friction pad 30 are moved away from the sheet feeding roller 40 by the restoring force of the uppermost sheet S1. For this reason, the uppermost sheet S1 is not sufficiently pressed against the paper feed roller 40 by the pressing means on the paper feed roller 40 by the pad means 31, and P1 (pressing force by the elastic force of the pad biasing member 32)> P2 ( In the worst case, when the restoring force due to the waist of the uppermost sheet S1 exceeds the urging force by the pad means 31, the uppermost sheet S1 is removed from the sheet feeding roller 40. It will separate and it will become impossible to detect appropriate 1st and 2nd urging | biasing force. As a result, at this time, sufficient transport force is not applied to the uppermost sheet S1, and a problem such as non-feeding of the uppermost sheet S1 occurs. Further, since the balance between the conveyance performance by the bottom plate 45 and the paper feed roller 40 and the separation performance by the friction pad 30 and the paper feed roller 40 are lost, for example, if the conveyance performance is excessive with respect to the separation performance, the double feeding of the paper Such a problem occurs. Also in the bottom plate 45 described in Patent Document 3, the urging force Q1 of the uppermost sheet S1 with respect to the paper feed roller 40 in the pressing urging portion of the bottom plate 45 against the paper feed roller 40 is not properly detected, causing a similar problem. easy.

  The present invention has been made in view of the above circumstances, and provides a separation sheet feeding device and an image forming apparatus capable of performing stable separation sheet feeding without double feeding and non-feeding by a friction pad method. For the purpose.

In order to solve the above-described problem, the invention according to claim 1 includes a bottom plate having a sheet stacking surface on which a sheet bundle is stacked;
A paper feed roller for transporting the uppermost paper in the paper bundle in the paper feed direction;
A friction pad for separating the uppermost sheet from the sheet bundle conveyed by the sheet feeding roller by a frictional force;
A separation sheet feeding device having a pad urging member that urges the pad means for supporting the friction pad against the sheet feeding roller;
A force sensor for detecting an urging force between the sheet feeding roller and the uppermost sheet in the pressing urging portion against the sheet feeding roller by the pad means from the sheet feeding roller side;
Pad urging member moving means for adjusting the urging force by the pad means by moving the pad urging member,
The pad urging member is moved by the pad urging member moving means according to the urging force detected by the force sensor, and the urging force by the pad means is adjusted.

According to a second aspect of the present invention, there is provided a bottom plate having a sheet stacking surface on which a bundle of sheets is stacked;
A paper feed roller for transporting the uppermost paper in the paper bundle in the paper feed direction;
A bottom plate biasing member that presses and biases the bottom plate against the paper feed roller;
A friction pad for separating the uppermost sheet from the sheet bundle conveyed by the sheet feeding roller by a frictional force;
A separation sheet feeding device having a pad urging member that urges the pad means for supporting the friction pad against the sheet feeding roller;
A force sensor for detecting an urging force between the sheet feeding roller and the uppermost sheet in the pressing urging unit against the sheet feeding roller by the bottom plate from the sheet feeding roller side;
A bottom plate urging member moving means for adjusting the urging force by the bottom plate by moving the bottom plate urging member;
The bottom plate urging member is moved by the bottom plate urging member moving means in accordance with the urging force detected by the force sensor, and the urging force by the bottom plate is adjusted.

According to a third aspect of the present invention, in the separation sheet feeding device according to the first aspect,
A first force sensor for detecting a first urging force between the sheet feeding roller and the uppermost sheet in the first pressing urging unit against the sheet feeding roller by the pad means from the sheet feeding roller side;
Pad urging member moving means for adjusting the second urging force by the pad means by moving the pad urging member;
A bottom plate biasing member that presses and biases the bottom plate against the paper feed roller;
A second force sensor for detecting a third urging force between the sheet feeding roller and the uppermost sheet in the second pressing urging unit against the sheet feeding roller by the bottom plate from the sheet feeding roller side;
A bottom plate urging member moving means for adjusting the fourth urging force by the bottom plate by moving the bottom plate urging member;
Adjusting the second urging force by the pad means by moving the pad urging member by the pad urging member moving means according to the first urging force detected by the first force sensor;
The fourth urging force by the bottom plate is adjusted by moving the bottom plate urging member by the bottom plate urging member moving means in accordance with a third urging force detected by the second force sensor.

According to a fourth aspect of the present invention, in the separation sheet feeding device according to any one of the first to third aspects,
A paper passage detection device for detecting the passage of the uppermost paper fed by the paper feed roller;
A counter that counts the number of sheets of the uppermost paper detected by the paper passage detection device;
An arithmetic device that calculates at least one of the urging force by the pad means and the urging force by the bottom plate from the number of sheets fed by the counter counted by the counter,
The pad urging member is moved by the pad urging member moving means based on the urging force of at least one of the predetermined urging force by the pad means and the predetermined urging force by the bottom plate calculated by the arithmetic unit. The bottom plate urging member is moved by the urging force by the pad means and the bottom plate urging member moving means to adjust at least one of the urging forces by the bottom plate.

According to a fifth aspect of the present invention, there is provided a bottom plate having a sheet stacking surface on which a bundle of sheets is stacked;
A paper feed roller for transporting the uppermost paper in the paper bundle in the paper feed direction;
A friction pad for separating the uppermost sheet from the sheet bundle conveyed by the sheet feeding roller by a frictional force;
A separation sheet feeding device having a pad urging member that urges the pad means for supporting the friction pad against the sheet feeding roller;
A paper thickness detection device for detecting the thickness of the uppermost paper;
Pad urging member moving means for adjusting the urging force of the pad means against the paper feed roller by moving the pad urging member;
The pad urging member is moved by the pad urging member moving means according to the paper thickness of the uppermost sheet detected by the paper thickness detecting device, and the urging force by the pad means is adjusted.

According to a sixth aspect of the present invention, there is provided a bottom plate having a sheet stacking surface on which a bundle of sheets is stacked;
A paper feed roller for transporting the uppermost paper in the paper bundle in the paper feed direction;
A bottom plate biasing member that presses and biases the bottom plate against the paper feed roller;
A friction pad for separating the uppermost sheet from the sheet bundle conveyed by the sheet feeding roller by a frictional force;
A separation sheet feeding device having a pad urging member that urges the pad means for supporting the friction pad against the sheet feeding roller;
A paper thickness detection device for detecting the thickness of the uppermost paper;
A bottom plate urging member moving means for adjusting the urging force of the bottom plate against the paper feed roller by moving the bottom plate urging member;
The bottom plate urging member is moved by the bottom plate urging member moving means in accordance with the paper thickness of the uppermost sheet detected by the paper thickness detecting device, and the urging force by the bottom plate is adjusted.

According to a seventh aspect of the present invention, in the separation sheet feeding device according to any one of the first to third aspects,
A paper passage detection device for detecting the passage of the uppermost paper fed by the paper feed roller;
A counter that counts the number of sheets of the uppermost paper detected by the paper passage detection device;
An arithmetic device that calculates at least one of the urging force by the pad means and the urging force by the bottom plate from the number of sheets fed by the counter counted by the counter,
The pad urging member is moved by the pad urging member moving means based on the urging force of at least one of the predetermined urging force by the pad means and the predetermined urging force by the bottom plate calculated by the arithmetic unit. The bottom plate urging member is moved by the urging force by the pad means and the bottom plate urging member moving means to adjust at least one of the urging forces by the bottom plate.

  According to an eighth aspect of the present invention, there is provided an image forming apparatus comprising the separation paper feeding device according to any one of the first to seventh aspects.

  According to the present invention, a force sensor for detecting an urging force between the sheet feeding roller and the uppermost sheet from the sheet feeding roller side in the pressing urging portion against the sheet feeding roller by the pad means, and the pad attached And a pad urging member moving means for adjusting the urging force by the pad means by moving the urging member, and the pad urging member is moved by the pad urging member moving means according to the urging force generated by the force sensor. A separation sheet feeding device and an image forming apparatus capable of performing stable separation sheet feeding without double feeding and non-feeding by a friction pad method by adjusting the urging force by the pad means by moving be able to.

  Further, according to the present invention, a force sensor that detects an urging force between the sheet feeding roller and the uppermost sheet from the sheet feeding roller side in the pressing urging portion against the sheet feeding roller by the bottom plate, and the bottom plate A bottom plate urging member moving means for adjusting the urging force by the bottom plate by moving the urging member, and the bottom plate urging force by the bottom plate urging member moving means according to the urging force detected by the force sensor Provided is a separation sheet feeding device and an image forming apparatus capable of performing stable separation feeding without double feeding and non-feeding by a friction pad method by adjusting a biasing force by the bottom plate by moving a member. be able to.

  According to the present invention, the sheet thickness detecting device for detecting the thickness of the uppermost sheet, and the pad urging force for adjusting the urging force of the pad means against the sheet feeding roller by moving the pad urging member. Member moving means, and the pad urging member moving means moves the pad urging member according to the paper thickness of the uppermost sheet detected by the paper thickness detecting device, and the urging force by the pad means is applied. By adjusting, it is possible to provide a separation sheet feeding device and an image forming apparatus capable of performing stable separation sheet feeding without double feeding and non-feeding by the friction pad method.

    Further, according to the present invention, a paper thickness detection device that detects the thickness of the uppermost sheet, and a bottom plate urging member that adjusts the urging force of the bottom plate against the paper feed roller by moving the bottom plate urging member. Moving means, and adjusting the urging force by the bottom plate by moving the bottom plate urging member by the bottom plate urging member moving means according to the paper thickness of the uppermost sheet detected by the paper thickness detecting device. Accordingly, it is possible to provide a separation sheet feeding device and an image forming apparatus that can perform stable separation sheet feeding without double feeding and non-feeding by the friction pad method.

It is a longitudinal cross-sectional view which shows schematic structure of the separation paper feeder which concerns on 1st Embodiment by this invention. FIG. 2 is a front view of the separation A paper feeding device shown in FIG. It is a side view which shows schematic structure of the force sensor used with the separation paper feeder shown in FIG. It is a longitudinal cross-sectional view which shows the separation paper feeder of 2nd Embodiment by this invention. It is the front view seen from the sheet feeding direction upstream which shows schematic structure of the separation sheet feeding apparatus of 2nd Embodiment by this invention. It is a side view which shows schematic structure of the force sensor used with the separation paper feeder of 2nd Embodiment by this invention. It is a longitudinal cross-sectional view which shows schematic structure of the separation paper feeder of 3rd Embodiment by this invention. The separation paper feeder according to the fourth embodiment of the present invention is also a longitudinal sectional view showing a schematic configuration. It is a longitudinal cross-sectional view which shows schematic structure of the separation paper feeder of 5th Embodiment by this invention. It is a longitudinal cross-sectional view which shows schematic structure of the separation paper feeder which concerns on 6th Embodiment by this invention. It is a side view which shows schematic structure of the paper thickness detection apparatus used with the separation paper feeder shown in FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. It is a longitudinal cross-sectional view which shows schematic structure of the separation paper feeder of 7th Embodiment by this invention. It is a longitudinal cross-sectional view which shows schematic structure of the separation paper feeder which concerns on 8th Embodiment by this invention. It is a longitudinal cross-sectional view which shows schematic structure of the separation paper feeder which concerns on 9th Embodiment by this invention. It is a longitudinal cross-sectional view which shows schematic structure of the separation paper feeder of 10th Embodiment by this invention. It is sectional drawing which shows schematic structure of the conventional separation paper feeder. FIG. 18 is a side view showing a paper feeding state by the separation paper feeding device shown in FIG. 17.

  Hereinafter, a separation sheet feeding device according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view showing a schematic configuration of a separation sheet feeding device according to a first embodiment of the present invention. FIG. 2 is a front view of the separation A sheet feeding device shown in FIG. FIG. 3 is a side view illustrating a schematic configuration of a force sensor used in the separation sheet feeding device illustrated in FIG. 1.

  In the separation sheet feeding device 2 according to the first embodiment, as shown in FIG. 2, the sheet feeding rollers 40A and 40B include a right end 40Aa of the sheet feeding roller 40A and a left end 40Ba of the sheet feeding roller 40B. Are connected to a rotating shaft 41 that is pivotally supported on the apparatus main body side (not shown) such as a copying machine in a state where they are separated by a predetermined interval. When the rotary shaft 41 is rotated in the direction of arrow A shown in FIG. 1 by a drive motor (not shown), the paper feed rollers 40A and 40B are rotated at a constant speed.

  Further, as shown in FIG. 1, the friction pad 30 pressed against the paper feed rollers 40A and 40B feeds the uppermost paper S1 to the bottom plate 45 described later (in the direction of arrow D). Is disposed at a position facing the paper feed rollers 40 </ b> A and 40 </ b> B and is supported on the upper portion of the pad means 31. The friction pad 30 is mainly composed of a friction member such as cork, and is inserted between the friction pad 30 and the paper feed rollers 40A and 40B as the paper feed rollers 40A and 40B rotate as will be described later. Of the plurality of sheets from the sheet bundle S0, only the uppermost sheet S1 is fed only by the frictional force between the friction pad 30 and the sheet.

  The pad means 31 is attached to a connecting portion 61, and the connecting portion 61 includes a friction pad 30 attached to the pad means 31 on a connecting device 60 attached to a paper feed cassette (not shown). It is attached so as to be movable in the direction (arrow B direction) toward the rotation shaft 41 of 40B. Further, a pad urging member support portion 62 is attached below the connecting portion 61 of the connecting device 60 so as to be movable in the arrow B direction. A pad urging member 32 such as a coil spring is inserted between the lower end of the pad unit 31 and the pad urging member support 62 in order to press the pad unit 31 against the paper feed rollers 40A and 40B. The urging force P1 by the pad means 31 which is a pressure contact force is generated by the elastic force of the pad urging member 32. This urging force P1 can be varied by moving the pad urging member support 62 in the direction of arrow B to vary the length of the pad urging member 32. This point will be described later.

  Further, in a paper feed cassette described later, a bottom plate 45 having a paper stacking surface 45a on which the sheet bundle S0 is placed is disposed, and the front end of the paper stacking surface 45a faces the paper feed rollers 40A and 40B. It is attached so that it can move up and down in the direction of arrow C. One end of a bottom plate urging member 46 such as a coil spring is attached to the front end of the bottom plate 45, and the other end of the bottom plate urging member 46 is a base on the apparatus main body side (not shown) such as a copying machine (not shown). It is supported by a bottom plate biasing member support 47 formed on the top. The front end of the uppermost sheet S1 of the sheet bundle S0 on the bottom plate 45 is pressed against the paper feed rollers 40A and 40B by the biasing force P3 due to the elastic force of the bottom plate biasing member 46 against the paper feed rollers 40A and 40B. It has come to be. Accordingly, when the paper feed rollers 40A and 40B rotate in the direction of arrow A shown in FIG. 1, the paper including the uppermost paper S1 in the paper bundle S0 receives frictional force from the paper feed rollers 40A and 40B, and the paper feed rollers 40A. , 40B and the friction pad 30. When a plurality of sheets enter between the sheet feed rollers 40A, 40B and the friction pad 30 at the same time, the friction coefficient between the sheet feed rollers 40A, 40B and the uppermost sheet S1, the lower layer of the uppermost sheet S1 and the uppermost sheet S1. The paper is separated by the frictional force difference due to the friction coefficient between the friction pad 30 and the friction pad 30 and the friction coefficient between the friction pad 30 and the paper on the friction pad 30, and only one of the uppermost paper S 1 is transferred to the main unit. Paper is fed.

  In such a separating paper feeding device 2, if the urging force P1 by the pad means 31 is not properly adjusted, double feeding and non-feeding of paper occur. For this purpose, in the separation paper feeding device 2 according to the first embodiment, as shown in FIGS. 1 and 2, the pressing means T1 (feeding roller 40A, The biasing force P2 between the paper feeding rollers 40A and 40B and the uppermost paper S1 in the pressing biasing portion T1 on the side of the paper feeding rollers 40A and 40B) (the portion where the uppermost paper S11 in pressure contact with 40B is pressed and biased) Is provided.

  Furthermore, as described above, the pad means 31 is pressed against the paper feed rollers 40A and 40B by the pad biasing member 32 with the biasing force P1, and this biasing force P1 is applied to the pad biasing member. It varies with the length L1 of 32. In order to adjust the urging force P1 to an appropriate value, as shown in FIG. 1, the pad urging member support 62 supporting the pad urging member 32 is movable in the direction of arrow B on the coupling device 60. Is attached. The pad urging member support 62 is moved in the direction of arrow B by the pad urging member moving means 35 to vary the length L1 of the pad urging member 32. Here, the pad urging member moving means 35 is, for example, a stepping motor 63, and the signal transmitted by the arithmetic device 52 is, for example, a pulse signal for operating the stepping motor 63. Then, by rotating the rotation shaft 63a of the stepping motor 63 screwing the pad urging member support portion 62 and the rotation shaft 63a, the pad urging member support portion 62 is moved in the arrow B direction to move the pad urging member. The urging force P1 can be varied by operating the pad urging member moving means 35 that varies the length L1 of 32.

Further, the rotation speed of the stepping motor 63 is adjusted by the arithmetic unit 52 based on the urging force P2 between the paper feeding rollers 40A and 40B and the uppermost sheet S1 in the pressing urging unit T1 detected by the force sensor 34. It has come to be. In this case, for example, the arithmetic unit 52 calculates the target value PT of the urging force P1 by the pad means 31 based on the following arithmetic expression, and the rotational speed of the stepping motor 63 is controlled so as to be the target value PT. It has become so.
Formula: If P2 <P2min, PT = P1 + dP, if P2> P2max, PT = P1-dP, and if P2min <P2 <P2max, keep the original state. In the above formula, P2min and P2max respectively indicate the minimum value and the maximum value of the target urging force between the paper feeding rollers 40A and 40B and the uppermost sheet S1 in the pressing urging unit T1, and dP is the pad urging force. This is a change amount of the urging force by the member 32. Note that P2min, P2max, and dP are stored in memory means in the arithmetic unit 52. As described above, the urging force P2 between the paper feed rollers 40A and 40B and the uppermost sheet S1 is detected from the output signal of the force sensor 34 by the arithmetic unit 52, and the urging force P1 by the pad means 31 is calculated. Then, it is determined whether the urging force is appropriate (for example, whether the urging force P1 is the target value PT). If not, the pad urging member moving means 35 is operated to make it appropriate. The urging force P1 can be adjusted appropriately.

  Further, as shown in FIG. 3, the force sensor 34 includes a roller 36 that rotates in contact with the uppermost sheet S1, a load cell 37 that detects a pressing force that the uppermost sheet S1 presses the roller 36, an arm 38, and an arm 38. A force sensor urging member 42 including a spring or the like that urges and presses the uppermost sheet S1 at the urging portion T1 that presses the roller 36 via the linear slider 39 and the arm 38. The force sensor 34 is attached to a fixing member 43 that is fixed to the apparatus main body via a force sensor biasing member 42. The roller 36 is a free roller that rotates in the paper feeding direction D (see FIG. 1) of the uppermost sheet S1, and does not substantially affect the conveyance of the uppermost sheet S1. The roller 36 is displaced only by a linear slider 39 in a direction perpendicular to the surface of the uppermost sheet S1.

  When the friction pad 30 (pad means 31) urges the uppermost sheet S1 toward the paper feed rollers 40A and 40B, the uppermost sheet S1 presses the roller 36 with the urging force P2, and the load cell 37 detects this P2. It has become. Information detected by the load cell 37 is transmitted to the arithmetic device 52. The arithmetic unit 52 determines whether the urging force P2 is appropriate, and transmits a signal for moving the pad urging member moving unit 35 to the pad urging member moving unit 35 to make it appropriate if not appropriate. The pad urging member moving means 35 moves the pad urging member 32 based on the signal transmitted from the arithmetic device 52 and adjusts the urging force P1.

  As described above, in the separation sheet feeding device according to the first embodiment, the force sensor 34 that measures the biasing force P2 between the sheet feeding rollers 40A and 40B and the uppermost sheet S1 on the sheet feeding rollers 40A and 40B side. Since the urging force P2 is accurately detected as appropriate, the urging force P1 can be adjusted to the target value PT by the pad urging member moving means 35. As a result, the urging force P1 by the pad means 31 can be returned to an appropriate value, and stable paper feeding without double feeding or non-feeding becomes possible. In the implementation, the target value PT may be within an allowable range with an appropriate width.

  Further, according to the first embodiment, since the movement of the pad urging member 32 is controlled by the number of steps of the stepping motor 63, the position of the pad urging member 32 need not be detected by a sensor or the like and fed back.

  In the present invention, the “pressing urging portion for the sheet feeding roller by the pad means” is on and near the line G (see FIG. 2) where the friction pad 30 and the sheet feeding rollers 40A and 40B are in pressure contact (for example, the line). G is a region in which the urging force P2 between the feed rollers 40A and 40B and the uppermost sheet S1 is substantially equal in a region displaced by ± 10 mm in the paper feeding direction from G. Therefore, as the position where the force sensor 34 is disposed, the sheet feeding rollers 40A and 40B divided in the middle are used as the sheet feeding rollers as in the first embodiment, and the divided sheet feeding rollers 40A and 40B are used. In addition to disposing the force sensor 34 in the pressing biasing portion T1 between the two, a single sheet feeding roller is used, and either one of both ends in the axial direction is used as the pressing biasing portion T1. A force sensor 34 may be disposed on the urging portion T1. However, as in the first embodiment, the sheet feeding rollers 40A and 40B divided in the middle are used as the sheet feeding rollers, and the force sensor 34 is disposed in the pressing biasing portion T1 during the division. In this case, it is preferable because the biasing force P can be detected more accurately.

  Next, a separation sheet feeding device according to a second embodiment of the present invention will be described with reference to FIGS. In addition, about the part same as the part demonstrated in 1st Embodiment, the same code | symbol is used and detailed description is abbreviate | omitted (it is the same also in the following embodiment). FIG. 4 is a longitudinal sectional view showing a separation sheet feeding device according to a second embodiment of the present invention. FIG. 5 is a front view showing a schematic configuration of the separation sheet feeding device according to the second embodiment of the present invention as viewed from the upstream in the sheet feeding direction. FIG. 6 is a side view showing a schematic configuration of a force sensor used in the separation sheet feeding device according to the second embodiment of the present invention.

  As shown in FIG. 4, the separation sheet feeding device 3 according to the second embodiment is different from the separation sheet feeding device 2 according to the first embodiment described above between the sheet feeding rollers 40A and 40B and the uppermost sheet S1. The urging force for pressing the bottom plate 45 against the paper feed rollers 40A and 40B by the bottom plate urging member 46 based on the arrangement position of the force sensor 49 for detecting the urging force Q2 and the urging force Q1 detected by the force sensor 49. The difference is that Q1 is adjusted. That is, the bottom plate 45 presses the uppermost sheet S1 against the sheet feeding rollers 40A and 40B, and the sheet feeding rollers 40A and 40B and the uppermost sheet S1 are disposed on the sheet feeding rollers 40A and 40B side of the pressing urging unit T2. The force sensor 49 for detecting the urging force Q2 between them and the bottom plate urging member support 47 are moved in the direction of arrow C to change the length L2 of the bottom plate urging member 46 to adjust the urging force Q1 by the bottom plate 45. And a bottom plate urging member moving means 48.

Then, the urging force Q1 is calculated from the output signal of the force sensor 49 to determine whether the urging force is appropriate (for example, whether the urging force Q1 is the target value QT). An arithmetic device 52 is provided that transmits a signal for moving the urging member moving means 48 to the bottom plate urging member moving means 48. In this case, for example, the arithmetic unit 52 calculates a target value QT of the urging force Q1 by the bottom plate 45 based on the following arithmetic expression, and the rotational speed of the stepping motor 64 is controlled so as to be the target value QT. It is like that.
Arithmetic formula: If Q2 <Q2min, QT = Q1 + dQ. If Q2> Q2max, QT = Q1-dQ. If Q2min <Q2 <Q2max, the original state is maintained. In the above formula, Q2min and Q2max indicate the minimum value and the maximum value of the target urging force between the paper feeding rollers 40A and 40B and the uppermost sheet S1 in the pressing urging unit T2, respectively, and dQ depends on the bottom plate 45. This is the amount of change in biasing force. Note that Q2min, Q2max, and dQ are stored in memory means in the arithmetic unit 52. In this manner, the computing device 52 detects the urging force Q2 between the paper feeding rollers 40A and 40B and the uppermost sheet S1 from the output signal of the force sensor 49, and calculates the urging force Q1 by the bottom plate 45. Then, it is determined whether the urging force is appropriate (for example, whether the urging force Q1 is the target value QT). If not, the bottom plate urging member moving means 48 is operated to make it appropriate. It is possible to adjust Q1 appropriately. In the implementation, the target value QT may have an appropriate range to be within the allowable range.

  For example, as shown in FIG. 5, the force sensor 49 is disposed in the pressing biasing portion T <b> 2 between the paper feed rollers 40 </ b> A and 40 </ b> B. Further, as shown in FIG. 6, the force sensor 49 includes a roller 54 that rotates in contact with the uppermost sheet S <b> 1, a load cell 55 that detects compression force, an arm 56, a linear slider 57 that regulates the movement of the arm 56, and an arm. And a force sensor urging member 58 for urging. The force sensor 49 is in contact with the fixing member 59 via the force sensor urging member 58. The fixing member 59 is fixed to the apparatus main body side. The roller 54 is a free roller that rotates in a state that does not affect the conveyance of the uppermost sheet S1 as the uppermost sheet S1 moves in the paper feeding direction D. The roller 54 is displaced only in the direction perpendicular to the surface of the uppermost sheet S1 by the linear slider 57.

  When the bottom plate 45 urges the uppermost sheet S1 toward the feed rollers 40A and 40B, as shown in FIG. 4, the uppermost sheet S1 presses the roller 25 with the urging force Q2, and the load cell 55 detects this Q2. . Information detected by the load cell 55 is transmitted to the arithmetic device 52. The arithmetic unit 52 determines whether the urging force Q2 is appropriate, and transmits a signal for moving the bottom plate urging member moving unit 48 to the bottom plate urging member moving unit 48 to make it appropriate if not appropriate. The bottom plate urging member moving means 48 moves the bottom plate urging member 46 based on the signal transmitted from the arithmetic device 52 and adjusts the urging force Q1. Here, the bottom plate urging member moving means 48 is, for example, a stepping motor 64, and a pinion gear attached to the rotating shaft 64a of the stepping motor 64 and a rack 47a attached to the bottom plate urging member support 47 are teethed. Accordingly, the rotation of the rotating shaft 64a of the stepping motor 64 causes the bottom plate urging member support portion 47 to move up and down in the direction of arrow C, so that the length L2 of the bottom plate urging member 46 can be varied. By varying the length L2 of the bottom plate urging member 46, the urging force Q1 on the paper feed rollers 40A and 40B by the bottom plate 45 can be varied. Here, the signal transmitted by the arithmetic unit 52 is, for example, a pulse signal that operates the stepping motor 64.

  Therefore, according to the separation sheet feeding device 3 according to the second embodiment of the present invention, the force sensor 49 for measuring the urging force Q2 by the bottom plate 45 is disposed on the sheet feeding rollers 40A and 40B side, whereby the sheet feeding roller 40A. , 40B and the uppermost sheet S1 can be accurately detected as appropriate, and the bottom plate biasing member moving means 48 can adjust the biasing force Q1 by the bottom plate 45 to the target value QT. As a result, the urging force can be returned to an appropriate value, and stable paper feeding without double feeding or non-feeding becomes possible.

  In the present invention, the “pressing urging portion for the sheet feeding roller by the bottom plate” is on and near the line H (see FIG. 5) where the uppermost sheet S1 and the sheet feeding rollers 40A and 40B are in pressure contact (for example, the bottom plate 45). In the region within 100 mm from the front end 45a), the urging force Q2 between the paper feed rollers 40A and 40B and the uppermost sheet S1 is substantially equal. Therefore, as the position where the force sensor 49 is disposed, the sheet feeding rollers 40A and 40B divided in the middle are used as the sheet feeding rollers as in the second embodiment, and the divided sheet feeding rollers 40A and 40B are used. In addition to disposing the force sensor 49 in the pressing urging portion T2 between the two, a single sheet feeding roller is used, and either one of both ends in the axial direction is used as the pressing urging portion T2. A force sensor 49 may be disposed on the urging portion T2. However, as in the second embodiment, the sheet feeding rollers 40A and 40B divided in the middle are used as the sheet feeding rollers, and the force sensor 49 is arranged in the pressing biasing portion T2 during the division. In this case, it is preferable because the biasing force Q can be detected more accurately.

  Further, according to the present embodiment, since the movement of the bottom plate urging member 46 is controlled by the number of steps of the stepping motor 64, the position of the bottom plate urging member 46 does not need to be fed back by a sensor or the like.

  Next, a separation sheet feeding device according to a third embodiment of the present invention will be described with reference to FIG. The same parts as those described in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 7 is a longitudinal sectional view showing a schematic configuration of a separation sheet feeding device according to a third embodiment of the present invention.

  As shown in FIG. 7, the separation sheet feeding device 4 according to the third embodiment includes a force sensor (first force sensor) 34, a pad urging member moving unit 35, and a second force in the first embodiment described above. Both the force sensor (second force sensor) 49 and the bottom plate urging member moving means 48 in the embodiment are provided, and the second urging force by the pad means 31 in response to the detection of the first urging force P2 by the first force sensor 34. In accordance with the adjustment of P1 and the detection of the third urging force Q2 by the second sensor 49, the adjustment of the fourth urging force Q1 by the bottom plate 45 is performed simultaneously. That is, the first urging force between the sheet feeding rollers 40A and 40B and the uppermost sheet S1 is provided on the sheet feeding rollers 40A and 40B side of the first pressing urging unit T1 where the friction pad 30 presses the sheet feeding rollers 40A and 40B. A first force sensor 34 that detects P2 and a pad urging member moving unit 35 that adjusts the urging force between the sheet feeding rollers 40A and 40B and the uppermost sheet S1 by moving the pad urging member 32 in the direction of arrow B. Then, the biasing force Q2 between the paper feeding rollers 40A, 40B and the uppermost paper S1 is detected on the side of the paper feeding rollers 40A, 40B of the second pressing biasing portion T2 where the bottom plate 45 presses the paper feeding rollers 40A, 40B. The second force sensor 49 and the bottom plate urging member 46 are moved in the direction of arrow C to adjust the urging force Q1 between the paper feeding rollers 40A, 40B and the uppermost sheet S1 by the bottom plate 45. 48 The urging forces P1 and Q1 are calculated from the output signals of the first force sensor 34 and the second force sensor 49, and it is judged whether these urging forces P1 and Q1 are appropriate. An arithmetic unit 52 is provided for transmitting signals for operating the biasing member moving means 35 and the bottom plate biasing member moving means 48 to the pad biasing member moving means 35 and the bottom plate biasing member moving means 48. For example, as shown in FIGS. 2 and 5, the first force sensor 34 and the second force sensor 49 are disposed between the paper feed rollers 40 </ b> A and 40 </ b> B.

  Information detected by the load cell 37 of the first force sensor and the load cell 55 of the second force sensor is transmitted to the arithmetic device 52. The arithmetic device 52 determines whether the second urging force P1 and the fourth urging force Q1 are appropriate as in the first embodiment and the second embodiment. The target values PT and QT are calculated by the arithmetic expressions stored in 52, and based on the result, a signal for moving the pad urging member moving means 35 is sent from the arithmetic device 52 to the pad urging member moving means 35. A signal for moving the bottom plate urging member moving unit 48 is transmitted to the bottom plate urging member moving unit 48, respectively, so that the appropriate second urging force P1 and fourth urging force Q1 are obtained. 35 and the bottom plate urging member moving means 48 are operated.

  As described above, according to the separation sheet feeding device 4 according to the third embodiment, the first force sensor 34 that measures the first urging force P2 by the pad unit 31 is disposed on the sheet feeding rollers 40A and 40B side. By arranging the second force sensor 23 for measuring the third urging force Q2 by the bottom plate 45 on the rollers 40A and 40B side, respectively, the first urging force P2 and the first urging force P2 between the sheet feeding rollers 40A and 40B and the uppermost sheet S1. 3 urging force Q2 is accurately detected as appropriate, the second urging force P1 by the pad means 31 is set to the target value PT by the pad urging member moving means 35, and the fourth urging force Q1 by the bottom plate 45 by the bottom plate urging member moving means 48. Can be adjusted to the target value QT. As a result, the second and fourth urging forces P1 and Q1 can be returned to appropriate values, and stable paper feeding without double feeding or non-feeding is possible.

  Further, according to the present embodiment, the movement of the pad urging member 32 is controlled by the number of steps of the stepping motor 63 and the movement of the bottom plate urging member 46 is controlled by the number of steps of the stepping motor 64. The position and the position of the bottom plate urging member 46 need not be fed back by a sensor or the like. In the implementation, the target values PT and QT may be given an appropriate width to be within the allowable range.

  Next, a separation sheet feeding device according to a fourth embodiment of the present invention will be described with reference to FIG. In addition, about the part same as the part demonstrated by the above-mentioned embodiment, the same code | symbol is used and detailed description is abbreviate | omitted. FIG. 8 is a longitudinal sectional view showing a schematic configuration of a separation sheet feeding device according to a fourth embodiment of the present invention.

  As illustrated in FIG. 8, the separation sheet feeding device 5 according to the fourth embodiment passes the sheet on the downstream side of the friction pad 30 in the sheet conveyance direction D with respect to the separation sheet feeding device 4 according to the third embodiment described above. A counter 50 that counts the number of fed sheets of the uppermost sheet S1 that has passed based on signals from the detection device 51 and the paper passage detection device 51 is added. The count information counted by the counter 50 is transmitted to the arithmetic device 52. Based on the count information transmitted from the counter, the arithmetic unit 52 estimates changes with time of the paper feed rollers 40A and 40B and the friction pad 30 (for example, deterioration due to wear, the influence of piled paper dust, etc.) Based on the result, the aforementioned target values PT and QT are corrected. Then, based on the corrected target values PT and QT, it is determined whether the second and fourth urging forces P1 and Q1 are appropriate. If not, for example, an arithmetic expression stored in the arithmetic device 52 is used. Based on the result, dP and dQ are calculated, and a signal for moving the pad urging member moving means 35 and a signal for moving the pad urging member moving means 35 and the bottom plate urging member moving means 48 are attached to the bottom plate. Each is transmitted to the force member moving means 48.

  Therefore, according to the fourth embodiment, the counter 50 that counts the number of the uppermost sheet S1 that has been fed is provided, so that changes with time of the feed rollers 40A and 40B and the friction pad 30 are predicted, and the arithmetic unit 52 calculates appropriate second and fourth urging forces P1 and Q1 in consideration of the change over time, and the second and fourth urging forces P1 and Q1 are calculated by the bottom plate urging member moving means 48 and the pad urging member moving means 35. Can be adjusted. As a result, the second and fourth urging forces P1 and Q1 are adjusted to appropriate values in consideration of changes with time, and stable feeding without double feeding or non-feeding becomes possible. In the implementation, the target values PT and QT may be given an appropriate width to be within the allowable range.

  Next, a separation sheet feeding device according to a fifth embodiment of the present invention will be described with reference to FIG. In addition, about the part same as the part demonstrated by the above-mentioned embodiment, the same code | symbol is used and detailed description is abbreviate | omitted. FIG. 9 is a longitudinal sectional view showing a schematic configuration of a separation sheet feeding device according to a fifth embodiment of the present invention.

  As shown in FIG. 9, the separation sheet feeding device 6 according to the fifth embodiment has a third force sensor, such as a load cell, that detects an urging force P1 between the friction pad 30 and the uppermost sheet S1 on the friction pad 30 side. 71, a fourth force sensor for detecting the urging force Q1 between the bottom plate 45 and the uppermost sheet S1 on the bottom plate 45 side, for example, the load cell 72, and information including the output signal of the load cell 71 and the load cell 72, the pad means 31 and It is determined whether the urging forces P1 and Q1 by the bottom plate 45 are appropriate, and if not appropriate, signals for moving the pad urging member moving means 35 and the bottom plate urging member moving means 48 are moved. An arithmetic unit 52 for transmitting to the means 35 and the bottom plate urging member moving means 48 is provided.

  Information detected by the load cell 71 and the load cell 72 is transmitted to the arithmetic device 52. The computing device 52 determines whether the second and fourth urging forces P1 and Q1, the first urging force P2 detected by the first force sensor 34, and the third urging force Q2 detected by the second force sensor 49 are appropriate. If not appropriate, for example, target values PT and QT are calculated by an arithmetic expression stored in the arithmetic unit 52, and a signal for moving the pad urging member moving means 35 is calculated based on the result. A signal for moving the bottom plate biasing member moving unit 48 is transmitted to the pad biasing member moving unit 35 to the bottom plate biasing member moving unit 48.

  Therefore, according to the fifth embodiment, the load cell 71 for measuring the urging force P1 by the pad means 31 and the load cell 72 for measuring the urging force Q1 by the bottom plate 45 are arranged, respectively, so that the feed rollers 40A and 40B Not only the urging forces P2 and Q2 between the uppermost sheets S1, but also P1 and Q1 are accurately detected as appropriate, target values PT and QT are calculated in consideration of P1 and Q1, and applied by the pad urging member moving means 35. The urging force P2 can be adjusted to the target value PT, and the urging force Q2 can be adjusted to the target value QT by the bottom plate urging member moving means 48. As a result, the second and fourth urging forces P1 and Q1 can be returned to appropriate values, and stable paper feeding without double feeding or non-feeding is possible. In the implementation, the target values PT and QT may be given an appropriate width to be within the allowable range.

  Next, a separation sheet feeding device according to a sixth embodiment of the present invention will be described in detail with reference to FIGS. In addition, about the part same as the part demonstrated by the above-mentioned embodiment, the same code | symbol is used and detailed description is abbreviate | omitted. FIG. 10 is a longitudinal sectional view showing a schematic configuration of a separation sheet feeding device according to a sixth embodiment of the present invention. FIG. 11 is a side view showing a schematic configuration of a paper thickness detecting device used in the separation paper feeding device shown in FIG.

  In the separation sheet feeding device 7 according to the sixth embodiment, the sheet feeding roller 40 is formed by a single roller, unlike the separation sheet feeding devices 2 to 6 of the first to fifth embodiments described above. The rotating shaft 41 is pivotally supported on the apparatus body side (not shown) such as a copying machine, and the rotating shaft 41 is rotated in the direction of arrow A by a drive motor (not shown). The friction pad 30 pressed against the paper feed roller 40 is supported on the upper portion of the pad means 31. The friction pad 30 is mainly a friction member such as cork. The pad means 31 is connected to a paper feed cassette (not shown) by a connecting device 60. And the pad means 31 is connected by the connection part 61 of the connection apparatus 60 so that sliding is possible in the arrow B direction. In order to press the pad means 31 against the paper feed roller 40, a pad urging member 32 such as a coil spring is inserted between the pad means 31 and the pad urging member support 62 of the coupling device 60, A pad urging force P <b> 1 that is a pressure contact force is generated by the elastic force of the pad urging member 32.

  In a sheet feeding cassette (not shown), a bottom plate 45 is rotatably supported by a support shaft 45c at its rear end. The bottom plate 45 is pressed by the urging force Q1 in the direction of arrow C by a bottom plate urging member 46 such as a coil spring supported by the bottom plate urging member support 47. A sheet bundle S0 is stacked on a sheet stacking surface 45a which is the upper surface of the bottom plate 45. The uppermost sheet S1 of the sheet bundle S0 is pressed against the sheet feeding roller 40 by the elastic force of the bottom plate urging member 46. At this time, when the paper feed roller 40 rotates in the direction of arrow A in FIG. 10, the uppermost paper S <b> 1 receives a frictional force from the paper feed roller 40 and enters between the paper feed roller 40 and the friction pad 30. When a plurality of sheets enter between the sheet feed roller 40 and the friction pad 30 at the same time, the sheets are separated due to the difference in frictional force due to the difference in friction coefficient, and only one sheet is fed to the main device.

  As shown in FIG. 10, the separation paper feeding device 7 according to the sixth embodiment includes a paper thickness detection device 80 that detects the paper thickness of the uppermost paper S <b> 1 above the bottom plate 45, and a coupling device 60. The pad urging member moving means 35 for adjusting the pad urging force P1 by moving the pad urging member 32 attached to the pad urging member supporting portion 62 movably attached in the arrow B direction in the arrow B direction. I have. Further, the target value PT of the urging force P1 by the pad means 31 is calculated from the output signal of the paper thickness detecting device 80, and the pad urging member movement for moving the pad urging member 32 so as to be the target value PT. An arithmetic device 52 is provided for transmitting a signal for operating the means 35 to the pad urging member moving means 35.

  Further, as shown in FIG. 11, the paper thickness detection device 80 is in contact with the uppermost paper S1 and rotates 81, the arm 82, the linear slider 84 that regulates the movement of the arm 82, the displacement of the arm 82, that is, the paper thickness. A displacement sensor 85 for detecting the height and an arm urging member 83 for urging the arm 82 are provided. The paper thickness detection device 80 is fixed to the apparatus main body side by a fixing member 86 via an arm biasing member 83. The displacement sensor 85 irradiates the reflection surface 82a of the arm 82 with the light beam 85a, detects the reflected light, and detects the amount of vertical displacement of the arm 82. In this case, the roller 82 is a free roller that rotates without affecting the conveyance of the uppermost sheet S1. The rollers 82 are displaced only in the direction perpendicular to the surface of the uppermost sheet S1 by the linear slider 84.

  When the uppermost sheet S1 is conveyed by the paper feed roller 40 and the trailing edge S1a of the uppermost sheet S1 passes through the paper thickness detection device 80, the arm 82 of the paper thickness detection device 80 is equal to the paper thickness of the uppermost paper S1. Displace. Then, the displacement sensor 85 detects the displacement of the arm 82. Information detected by the displacement sensor 85 is transmitted to the arithmetic device 52. The arithmetic unit 52 calculates the thickness of the uppermost sheet S1 from the displacement information, and the target value PT of the urging force by the pad means 31 appropriate for the thickness is stored in, for example, a memory (not shown). It is calculated from the formula for calculating the paper thickness and the urging force. Then, a signal for moving the pad urging member moving means 35 is transmitted to the pad urging member moving means 35 in order to obtain the target value PT of the urging force by the pad means 31.

  The pad urging member moving means 35 moves the pad urging member 32 based on the signal transmitted from the arithmetic device 52 and adjusts the pad urging force P1. Here, the pad urging member moving means 35 is, for example, a stepping motor 63, and the signal transmitted by the arithmetic device 52 is, for example, a pulse signal for operating the stepping motor 63. Then, by rotating the rotating shaft 63a of the stepping motor 63 that is screwed with the pad urging member support portion 62, the pad urging member support portion 62 is moved in the arrow B direction, and the length L1 of the pad urging member 32 is obtained. The urging force P1 can be changed by operating the pad urging member moving means 35 for changing the urging force.

  Therefore, according to the sixth embodiment, the paper thickness detection device 80 that detects the paper thickness of the uppermost paper S1 is arranged, so that the paper thickness of the uppermost paper S1 is detected, and the appropriate thickness is determined from the paper thickness. The target value PT of the urging force by the appropriate pad means 31 is calculated, and the pad urging force P1 is adjusted by adjusting the length L1 of the pad urging member 32 by the pad urging member moving means 35. Can do. As a result, the pad urging force can be set to an appropriate value, and stable feeding without double feeding or non-feeding is possible.

  Further, according to the present embodiment, since the movement of the pad urging member 32 is controlled by the number of steps of the stepping motor 63, the position of the pad urging member 32 does not need to be fed back by a sensor or the like. In the implementation, the target value PT of the urging force by the pad means 31 may be set to an allowable range by giving an appropriate width.

  Next, a case where the separation sheet feeding device according to the sixth embodiment is applied to an image forming apparatus will be described with reference to FIG. FIG. 12 is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

  In FIG. 12, an endless transport belt 18 stretched around support rollers 17A and 17B, one of which is rotationally driven, is disposed at the center of the apparatus. By the rotational drive of 17B, the sheet S1 is transferred in the arrow K direction, and the sheet S1 as a recording material is transferred in the arrow K direction. Image forming devices 22C, 22M, 22Y, and 22K for forming cyan, magenta, yellow, and black toner images are disposed on the upper surface of the transport belt 18. These image forming apparatuses 22C, 22M, 22Y, and 22K are drum-shaped photoreceptors 19C, 19M, 19Y, and 19K that are rotationally driven by a drive motor (not shown), and the surfaces of these photoreceptors 19C, 19M, 19Y, and 19K. The electrostatic latent image is supplied with cyan, magenta, yellow, and black toner to the charging roller 20 for uniformly charging the toner and the electrostatic latent image formed on the photoconductors 19C, 19M, 19Y, and 19K. Development devices 21C, 21M, 21Y, and 21K that develop toner images of cyan, magenta, yellow, and black. Further, cyan, magenta, yellow, and black toner images formed on the photoconductors 19C, 19M, 19Y, and 19K are transferred onto the paper S1 by the transfer roller 25, and remain on the photoconductors 19C, 19M, 19Y, and 19K. A cleaning device 27 is provided for removing and cleaning the toner to be removed from the surfaces of the photoreceptors 19C, 19M, 19Y, and 19K.

  Above the image forming devices 22C, 22M, 22Y, and 22K, exposure LC, LM, LY, and LK corresponding to cyan, magenta, yellow, and black image information are provided on the photoconductors 19C, 19M, 19Y, and 19K. Exposure means 23 for irradiating the surface to form electrostatic latent images corresponding to cyan, magenta, yellow, and black image information on the photoreceptors 19C, 19M, 19Y, and 19K is disposed. Further, on the downstream side (left side of the drawing) of the conveyor belt 18, the toner image transferred onto the paper S 1 is fixed on the paper S 1, and the toner image is heated and pressed by the fixing device 15. A paper discharge means 24 for discharging the paper S1 on which the toner is fixed is disposed.

  In such a configuration, the charging roller 20 uniformly charges the surfaces of the photoreceptors 19C, 19M, 19Y, and 19K for each of the image forming devices 22K to 22C. Next, image data and character image data by a personal computer, an image scanner, etc. are exposed in dot units by the exposure means 23, and electrostatic latent images are formed on the uniformly charged surfaces of the photoconductors 19C, 19M, 19Y, and 19K. To form. After that, the electrostatic latent images corresponding to the cyan, magenta, yellow, and black image data are supplied and developed with cyan, magenta, yellow, and black toners by the developing devices 21C, 21M, 21Y, and 21K, respectively. It is visualized as a toner image of each color on the photoreceptors 19C, 19M, 19Y, and 19K.

  Further, in accordance with the toner image formation on the photoconductors 19C, 19M, 19Y, and 19K, the sheet S1 fed from the sheet holding unit 16 by the sheet supply unit 28 is conveyed to the conveyance belt 18 by the registration roller 26 at the same timing. The The sheet S1 held by the static electricity on the conveyor belt 18 is sequentially brought into contact with the photoreceptors 19C, 19M, 19Y, and 19K of the respective image forming devices as the conveyor belt 18 is transferred, and a transfer bias is applied from the transfer roller 25. As a result, the toner images of the respective colors formed on the photoreceptors 19C, 19M, 19Y, and 19K are stacked and transferred on the paper S1. As a result, four color toner images are formed on the sheet S1. The sheet S1 on which the color toner image is transferred in this way is conveyed from the conveyance belt 18 to the fixing device 15. The color toner image on the sheet S 1 is heated by the fixing device 15 by the fixing roller 13 heated by the fixing belt 12 heated by the heating roller 14 and is pressed by the pressure roller 11 in pressure contact with the fixing roller 13. Then, it is fixed on the sheet S 1 and discharged by the sheet discharge device 24.

  On the other hand, the toner remaining on the photoreceptors 19C, 19M, 19Y, and 19K having the toner image transferred onto the sheet S1 as described above is removed by the cleaning device 27. The cleaned photoconductors 19C, 19M, 19Y, and 19K return to the initial state, and the image forming operation is repeated in the same manner in preparation for the next image forming operation.

  Under such an image forming apparatus, a sheet feeding cassette 16 for stacking and storing a sheet bundle S0 of a predetermined size, a separation sheet feeding device 7 including a sheet feeding roller 40, and a registration roller 26 are arranged. As the separation paper feeding device 7, the separation paper feeding device 7 described in the sixth embodiment is used. The paper thickness detection device 80 detects the paper thickness of the uppermost paper S1, and the arithmetic device. In accordance with the paper thickness detected from 52, the pad urging member moving means 35 is operated to adjust the urging force P1 by the pad means 31. Therefore, the separation sheet feeding device 7 can stably feed the uppermost sheet S1 without double feeding or non-feeding. The uppermost sheet S1, the sheet bundle S0, the urging force P1, the sheet thickness detecting device 80, the pad urging member moving unit 35, the sheet feeding roller 40, and the pad unit 31 are described with reference to FIGS. Since the description has been given in the sixth embodiment, the description is omitted.

  In this image forming apparatus, the example in which the separation sheet feeding device 7 according to the sixth embodiment of the present invention is applied has been described. However, the other first to fifth embodiments and the seventh to tenth embodiments to be described later. The separation sheet feeding device according to the embodiment can also be appropriately applied.

  Next, a separation sheet feeding device according to a seventh embodiment of the present invention will be described with reference to FIG. In addition, about the part same as the part demonstrated by the above-mentioned embodiment, the same code | symbol is used and detailed description is abbreviate | omitted. FIG. 13 is a longitudinal sectional view showing a schematic configuration of a separation sheet feeding device according to a seventh embodiment of the present invention.

  As shown in FIG. 13, the separation sheet feeding device 8 according to the seventh embodiment is different from the separation sheet feeding device 7 according to the sixth embodiment described above in that the biasing force P <b> 1 by the pad means 31 is changed and adjusted. In addition, the urging force Q1 by the bottom plate 45 is variably adjusted. That is, the paper thickness detector 80, the bottom plate urging member moving means 48 for adjusting the urging force Q1 by the bottom plate 45 by moving the bottom plate urging member 46 up and down, and the bottom plate 45 from the output signal of the paper thickness detector 80. A signal for operating the bottom plate urging member moving means 48 for moving the bottom plate urging member 46 is calculated so that the target value QT of the urging force is calculated and becomes the target value QT of the urging force by the bottom plate 45. An arithmetic unit 52 for transmitting to the means 48 is provided.

  When the uppermost sheet S1 is conveyed by the paper feed roller 40 and the trailing edge of the uppermost sheet S1 passes through the paper thickness detection device 80, the arm 82 of the paper thickness detection device 80 is displaced by the thickness of the uppermost paper S1. To do. Then, the displacement sensor 85 detects the displacement of the arm 82. Information detected by the displacement sensor 85 is transmitted to the arithmetic device 52. The arithmetic unit 52 calculates the thickness of the uppermost sheet S1 from the displacement information, and the target value QT of the urging force by the bottom plate 45 appropriate to the thickness is stored in, for example, a memory (not shown). It is calculated from the relational expression between the paper thickness and the urging force Q1 by the bottom plate 45. Then, in order to obtain the target value QT of the urging force by the bottom plate 45, a signal for operating the bottom plate urging member moving unit 48 is transmitted to the bottom plate urging member moving unit 48. The bottom plate urging member moving means 48 moves the bottom plate urging member 46 based on the signal transmitted from the arithmetic device 52, and adjusts the urging force Q1 by the bottom plate 45. Here, the bottom plate urging member moving means 48 is, for example, a stepping motor 64, and a pinion gear attached to the rotating shaft 64a of the stepping motor 64 and a rack 47a attached to the bottom plate urging member support 47 are teethed. Accordingly, the rotation of the rotating shaft 64a of the stepping motor 64 causes the bottom plate urging member support portion 47 to move up and down in the direction of arrow C, so that the length L2 of the bottom plate urging member 46 can be varied. By varying the length L2 of the bottom plate urging member 46, the urging force Q1 on the paper feed rollers 40A and 40B by the bottom plate 45 can be varied. The signal transmitted by the arithmetic device 52 is, for example, a pulse signal that operates the stepping motor 64.

  Therefore, according to the seventh embodiment, the paper thickness detection device 80 that detects the paper thickness of the uppermost paper S1 is arranged, so that the paper thickness of the paper 3 is detected and an appropriate value is determined from the paper thickness. By calculating the target value QT of the urging force by the bottom plate 45 and adjusting the length L2 of the bottom plate urging member 46 to an appropriate length by the bottom plate urging member moving means 48, the urging force Q1 by the bottom plate 45 is adjusted. Can do. As a result, the urging force Q1 by the bottom plate 45 can be set to an appropriate value, and stable paper feeding without double feeding or non-feeding is possible.

  Further, according to the present embodiment, since the movement of the bottom plate urging member 46 is controlled by the number of steps of the stepping motor 64, the position of the bottom plate urging member 46 does not need to be fed back by a sensor or the like. In the implementation, the target value QT of the urging force by the bottom plate 45 may be set to an allowable range by giving an appropriate width.

  Next, a separation paper feeder according to an eighth embodiment of the present invention will be described with reference to FIG. In addition, about the part same as the part demonstrated by the above-mentioned embodiment, the same code | symbol is used and detailed description is abbreviate | omitted. FIG. 14 is a longitudinal sectional view showing a schematic configuration of a separation sheet feeding device according to an eighth embodiment of the present invention.

  As shown in FIG. 14, the separation sheet feeding device 9 according to the eighth embodiment includes the pad urging member moving means 35 of the separation sheet feeding device 7 according to the sixth embodiment and the separation according to the seventh embodiment. Both of the bottom plate urging member moving means 48 of the paper feeding device 8 are provided. That is, the paper thickness detecting device 80, the pad urging member moving means 35 for adjusting the urging force P1 by the pad means 31 by moving the pad urging member 32 in the arrow B direction, and the bottom plate urging member 46 in the arrow C direction. And a bottom plate urging member moving means 48 for adjusting the urging force Q1 by the bottom plate 45. Further, the target value PT of the urging force by the pad means 31 and the target value QT of the urging force by the bottom plate 45 are simultaneously calculated from the output signal of the paper thickness detection device 80, and the pad urging member 32 and the bottom plate urging member 46 are moved. And an arithmetic unit 52 for transmitting signals for operating the pad urging member moving means 35 and the bottom plate urging member moving means 48 to the pad urging member moving means 35 and the bottom plate urging member moving means 48. .

  When the uppermost sheet S1 is conveyed by the paper feed roller 40 and the trailing edge of the uppermost sheet S1 passes through the paper thickness detection device 80, the arm 82 of the paper thickness detection device 80 is displaced by the thickness of the uppermost paper S1. To do. Then, the displacement sensor 85 detects the displacement of the arm 82. Information detected by the displacement sensor 85 is transmitted to the arithmetic device 52. The computing device 52 calculates the thickness of the uppermost sheet S1 from the displacement information, and the pad means from the relational expression between the thickness and the biasing force P1 by the pad means 31 and the biasing force Q1 by the bottom plate 45. The target value PT of the urging force by 31 and the target value QT of the urging force by the bottom plate 45 are calculated. Then, a signal for operating the pad urging member moving means 35 is sent to the pad urging member moving means 35 so that the target value PT of the urging force by the pad means 31 and the target value QT of the urging force by the bottom plate 45 are obtained. A signal for operating the bottom plate urging member moving means 48 is transmitted to the bottom plate urging member moving means 48.

  The pad urging member moving means 35 adjusts the pad urging force by moving the pad urging member 32 based on the signal transmitted from the arithmetic device 52. Here, the pad urging member moving means 35 is, for example, a stepping motor 63, and the signal transmitted by the arithmetic device 52 is, for example, a pulse signal for operating the stepping motor 63. Further, the bottom plate urging member moving means 48 moves the bottom plate urging member 46 based on the signal transmitted from the arithmetic unit 52 and adjusts the bottom plate urging force. Here, the bottom plate urging member moving means 48 is, for example, a stepping motor 64, and the signal transmitted by the arithmetic device 52 is, for example, a pulse signal for operating the stepping motor 64.

  Therefore, according to the eighth embodiment, the paper thickness detecting device 80 for detecting the paper thickness of the uppermost paper S1 is arranged, so that the paper thickness of the uppermost paper S1 is detected and an appropriate pad is determined from the paper thickness. The target value PT of the urging force by the means 31 and the target value QT of the urging force by the bottom plate 45 are calculated, and the length L1 of the pad urging member 32 by the pad urging member moving means 35 and the bottom plate urging member moving means 48 are calculated. Thus, the pad biasing force P1 and the bottom plate biasing force Q1 can be adjusted by setting the length L2 of the bottom plate biasing member 45 to an appropriate length. As a result, the pad urging force P1 and the bottom plate urging force Q1 can be set to appropriate values, and stable paper feeding without double feeding or non-feeding is possible.

  Further, according to the present embodiment, since the movement of the pad urging member 32 is controlled by the number of steps of the stepping motor 63, the position of the pad urging member 32 does not need to be fed back by a sensor or the like. Similarly, according to the present embodiment, since the movement of the bottom plate urging member 46 is controlled by the number of steps of the stepping motor 64, the position of the bottom plate urging member 46 does not need to be fed back by a sensor or the like. In the implementation, the target value PT of the urging force by the pad means 31 and the target value QT of the urging force by the bottom plate 45 may be given an appropriate range so as to be within the allowable range.

  Next, a separation paper feeding device according to a ninth embodiment of the present invention will be described with reference to FIG. In addition, about the part same as the part demonstrated by the above-mentioned embodiment, the same code | symbol is used and detailed description is abbreviate | omitted. FIG. 15 is a longitudinal sectional view showing a schematic configuration of a separation sheet feeding device according to a ninth embodiment of the present invention.

  As illustrated in FIG. 15, the separation sheet feeding device 10 according to the ninth embodiment passes the sheet downstream of the friction pad 30 in the sheet conveyance direction D with respect to the separation sheet feeding device 9 according to the eighth embodiment described above. A counter 50 for counting the number of sheets that have passed based on signals from the detection device 51 and the paper passage detection device 51 is added. The count information counted by the counter 50 is transmitted to the arithmetic device 52. Based on the count information transmitted from the counter, the arithmetic device 52 estimates changes with time of the paper feed roller 40 and the friction pad 30 (for example, deterioration due to wear, the influence of accumulated paper dust, etc.), and the result is obtained. Based on this, the target value PT of the urging force by the pad means 31 and the target value QT of the urging force by the bottom plate 45 are calculated from, for example, a relational expression stored in a database (not shown). Then, in order to set the length L1 of the pad urging member 32 and the length L2 of the bottom plate urging member 46 to the respective target lengths, a signal for operating the pad urging member moving means 35 is sent to the pad urging member. A signal for operating the bottom plate urging member moving unit 48 is transmitted to the moving unit 35 to the bottom plate urging member moving unit 48.

  Therefore, according to the ninth embodiment, by providing the counter 50 that counts the number of the uppermost sheet S1 that has been fed, the temporal change of the paper feed roller 40 and the friction pad 30 is predicted, and the arithmetic unit 52 The target value PT of the urging force by the pad means 31 and the target value QT of the urging force by the bottom plate 45 in consideration of the change over time are calculated, and the length L1 of the pad urging member 32 is appropriately set by the pad urging member moving means 35. The pad biasing force P1 and the bottom plate biasing force Q1 can be adjusted by making the length and making the length L2 of the bottom plate biasing member 46 appropriate by the bottom plate biasing member moving means 48. As a result, the pad urging force P1 and the bottom plate urging force Q1 can be set to appropriate values, and stable paper feeding without double feeding or non-feeding is possible. In the implementation, the target value PT of the urging force by the pad means 31 and the target value QT of the urging force by the bottom plate 45 may be given an appropriate range so as to be within the allowable range.

  Next, a separation sheet feeding device according to a tenth embodiment of the present invention will be described with reference to FIG. In addition, about the part same as the part demonstrated by the above-mentioned embodiment, the same code | symbol is used and detailed description is abbreviate | omitted. FIG. 16 is a longitudinal sectional view showing a schematic configuration of a separation sheet feeding device according to a tenth embodiment of the present invention.

  As shown in FIG. 16, the separation paper feeder 28 according to the tenth embodiment includes a third force sensor, for example, a load cell, that detects an urging force P1 between the friction pad 30 and the uppermost sheet S1 on the friction pad 30 side. 71, a fourth force sensor for detecting the urging force Q1 between the bottom plate 45 and the uppermost sheet S1 on the bottom plate 45 side, for example, the load cell 72, and information including the output signal of the load cell 71 and the load cell 72, the pad means 31 and It is determined whether the urging forces P1 and Q1 by the bottom plate 45 are appropriate, and if not appropriate, signals for moving the pad urging member moving means 35 and the bottom plate urging member moving means 48 are moved. An arithmetic unit 52 for transmitting to the means 35 and the bottom plate urging member moving means 48 is provided.

  Information detected by the load cell 71 and the load cell 72 is transmitted to the arithmetic device 52. The arithmetic unit 52 determines whether the urging forces P1 and Q1 are appropriate for the uppermost paper S1 from the paper thickness information detected by the paper thickness detecting device 80. The target values PT and QT are calculated by arithmetic expressions stored in the device 52, and a signal for moving the pad urging member moving means 35 is sent to the pad urging member moving means 35 based on the result, and the bottom plate urging member A signal for moving the moving means 48 is transmitted to the bottom plate urging member moving means 48.

  Therefore, according to the tenth embodiment, the load cell 71 for measuring the pad biasing force P1 by the friction pad 30 and the load cell 72 for measuring the bottom plate biasing force Q1 by the bottom plate 45 are arranged, whereby the paper of the uppermost sheet S1. Not only the thickness but also P1 and Q1 are accurately detected as appropriate, the target value PT of the pad biasing force and the target value QT of the bottom plate biasing force are calculated, and the pad biasing member moving means 35 determines the pad biasing force P1 as the target value PT. Further, the bottom plate biasing member moving means 48 can adjust the bottom plate biasing force Q1 to the target value QT. As a result, the urging force can be returned to an appropriate value, and stable paper feeding without double feeding or non-feeding becomes possible. In the implementation, the target values PT and QT may be given an appropriate width to be within the allowable range.

  Further, the present invention is not limited to the above-described embodiment, and it is obvious that the above-described embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the above-described embodiment. In addition, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and can be set to a suitable number, position, shape, and the like in carrying out the present invention.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 28 Separating paper feeder 15 Fixing device 16 Paper cassette 17A, 17B Support roller 18 Conveying belt 19C, 19M, 19Y, 19K Photoconductor 20 Charging roller 21C, 21M, 21Y, 21K Developing device 22C, 22M, 22Y, 22K Image forming device 23 Exposure unit 24 Paper discharge unit 25 Transfer roller 26 Registration roller 27 Cleaning device 30 Friction pad 31 Pad unit 32 Pad biasing member 33 Force Sensor 34 Force sensor (first force sensor)
35 Pad urging member moving means 36 Roller 37 Load cell 38 Arm 39 Linear slider 40, 40A, 40B Paper feed roller 41 Rotating shaft 42 Force sensor urging member 43 Fixed member 45 Bottom plate 45a Paper stacking surface 45b Front end 45c Support shaft 46 With bottom plate Force member 47 Bottom plate urging member support 47a Rack 48 Bottom plate urging member moving means 49 Force sensor (second force sensor)
DESCRIPTION OF SYMBOLS 50 Counter 51 Paper passage detection apparatus 52 Calculation apparatus 54 Roller 55 Load cell 56 Arm 57 Linear slider 58 Force sensor urging member 59 Fixing member 60 Connection apparatus 61 Connection part 62 Pad urging member support part 63, 64 Stepping motor 71, 72 Load cell 80 Paper thickness detector 81 Roller 82 Arm 83 Arm biasing member 84 Linear slider 85 Load cell 86 Fixed member

Japanese Patent Laid-Open No. 55-135039 JP-A-5-238575 JP 2001-26326 A

Claims (8)

A bottom plate having a sheet loading surface on which a bundle of sheets is loaded;
A paper feed roller for transporting the uppermost paper in the paper bundle in the paper feed direction;
A friction pad for separating the uppermost sheet from the sheet bundle conveyed by the sheet feeding roller by a frictional force;
A separation sheet feeding device having a pad urging member that urges the pad means for supporting the friction pad against the sheet feeding roller;
A force sensor for detecting an urging force between the sheet feeding roller and the uppermost sheet in the pressing urging portion against the sheet feeding roller by the pad means from the sheet feeding roller side;
Pad urging member moving means for adjusting the urging force by the pad means by moving the pad urging member,
The separation sheet feeding device according to claim 1, wherein the pad urging member is moved by the pad urging member moving means in accordance with the urging force detected by the force sensor to adjust the urging force by the pad means. A bottom plate having a sheet loading surface on which a bundle of sheets is loaded;
A paper feed roller for transporting the uppermost paper in the paper bundle in the paper feed direction;
A bottom plate biasing member that presses and biases the bottom plate against the paper feed roller;
A friction pad for separating the uppermost sheet from the sheet bundle conveyed by the sheet feeding roller by a frictional force;
A separation sheet feeding device having a pad urging member that urges the pad means for supporting the friction pad against the sheet feeding roller;
A force sensor for detecting an urging force between the sheet feeding roller and the uppermost sheet in the pressing urging unit against the sheet feeding roller by the bottom plate from the sheet feeding roller side;
A bottom plate urging member moving means for adjusting the urging force by the bottom plate by moving the bottom plate urging member;
The separation sheet feeding device according to claim 1, wherein the bottom plate urging member is moved by the bottom plate urging member moving means in accordance with the urging force detected by the force sensor to adjust the urging force by the bottom plate. The separation sheet feeding device according to claim 1,
A first force sensor for detecting a first urging force between the sheet feeding roller and the uppermost sheet in the first pressing urging unit against the sheet feeding roller by the pad means from the sheet feeding roller side;
Pad urging member moving means for adjusting the second urging force by the pad means by moving the pad urging member;
A bottom plate biasing member that presses and biases the bottom plate against the paper feed roller;
A second force sensor for detecting a third urging force between the sheet feeding roller and the uppermost sheet in the second pressing urging unit against the sheet feeding roller by the bottom plate from the sheet feeding roller side;
A bottom plate urging member moving means for adjusting the fourth urging force by the bottom plate by moving the bottom plate urging member;
Adjusting the second urging force by the pad means by moving the pad urging member by the pad urging member moving means according to the first urging force detected by the first force sensor;
Separation characterized by adjusting the fourth urging force by the bottom plate by moving the bottom plate urging member by the bottom plate urging member moving means according to the third urging force detected by the second force sensor. Paper feeder. The separation sheet feeding device according to any one of claims 1 to 3,
A paper passage detection device for detecting the passage of the uppermost paper fed by the paper feed roller;
A counter that counts the number of sheets of the uppermost paper detected by the paper passage detection device;
An arithmetic device that calculates at least one of the urging force by the pad means and the urging force by the bottom plate from the number of sheets fed by the counter counted by the counter,
The pad urging member is moved by the pad urging member moving means based on the urging force of at least one of the predetermined urging force by the pad means and the predetermined urging force by the bottom plate calculated by the arithmetic unit. The separation sheet feeding apparatus is characterized in that at least one of the urging force by the bottom plate is adjusted by moving the bottom plate urging member by the urging force by the pad unit and the bottom plate urging member moving unit. A bottom plate having a sheet loading surface on which a bundle of sheets is loaded;
A paper feed roller for transporting the uppermost paper in the paper bundle in the paper feed direction;
A friction pad for separating the uppermost sheet from the sheet bundle conveyed by the sheet feeding roller by a frictional force;
A separation sheet feeding device having a pad urging member that urges the pad means for supporting the friction pad against the sheet feeding roller;
A paper thickness detection device for detecting the thickness of the uppermost paper;
Pad urging member moving means for adjusting the urging force of the pad means against the paper feed roller by moving the pad urging member;
Separation characterized in that the urging force by the pad means is adjusted by moving the pad urging member by the pad urging member moving means in accordance with the paper thickness of the uppermost sheet detected by the paper thickness detecting device. Paper feeder. A bottom plate having a sheet loading surface on which a bundle of sheets is loaded;
A paper feed roller for transporting the uppermost paper in the paper bundle in the paper feed direction;
A bottom plate biasing member that presses and biases the bottom plate against the paper feed roller;
A friction pad for separating the uppermost sheet from the sheet bundle conveyed by the sheet feeding roller by a frictional force;
A separation sheet feeding device having a pad urging member that urges the pad means for supporting the friction pad against the sheet feeding roller;
A paper thickness detection device for detecting the thickness of the uppermost paper;
A bottom plate urging member moving means for adjusting the urging force of the bottom plate against the paper feed roller by moving the bottom plate urging member;
Separation feeding characterized by adjusting the urging force by the bottom plate by moving the bottom plate urging member by the bottom plate urging member moving means according to the paper thickness of the uppermost sheet detected by the paper thickness detecting device. Paper device. The separation sheet feeding device according to any one of claims 1 to 3,
A paper passage detection device for detecting the passage of the uppermost paper fed by the paper feed roller;
A counter that counts the number of sheets of the uppermost paper detected by the paper passage detection device;
An arithmetic device that calculates at least one of the urging force by the pad means and the urging force by the bottom plate from the number of sheets fed by the counter counted by the counter,
The pad urging member is moved by the pad urging member moving means based on the urging force of at least one of the predetermined urging force by the pad means and the predetermined urging force by the bottom plate calculated by the arithmetic unit. The separation sheet feeding apparatus is characterized in that at least one of the urging force by the bottom plate is adjusted by moving the bottom plate urging member by the urging force by the pad unit and the bottom plate urging member moving unit.   An image forming apparatus comprising the separation sheet feeding device according to claim 1.

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