JPH07133034A - Paper feeding device - Google Patents

Abstract

PURPOSE:To prevent paper sheets from not being fed and being fed one upon another in a paper feeding device for feeding paper sheets separately one by one. CONSTITUTION:An auxiliary pressing body 13 for applying an auxiliary pressing force for pressing a frictional member 7 to a paper feeding roller 6 and a pressing force adjusting body 16 which is connected with a pick-up roller 4 and shifts integrally with the pick-up roller 4 are installed on the frictional member 7 pressed on the outer peripheral surface of the paper feeding roller 6. When the pick-up roller 4 is shifted to a contact position and carriers out paper feed, the auxiliary pressing body 13 is shifted to the position for releasing the application of the auxiliary pressing force by the pressing force adjusting body 16, and the pressing force which acts on the paper feeding roller 6 from the frictional member 7 is reduced to prevent the generation of a paper feed disabled state. Further, when the pick-up roller 4 shifts to a separation position, the pressing force adjusting body 16 is separated from the auxiliary pressing body 13, and applies an auxiliary pressing force to the frictional member 7, and the pressing force which acts on the paper feeding roller 6 from the frictional member 7 is increased to prevent the generation of double feed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus for feeding a plurality of sheets set in a sheet feeding section of a copying machine, a printer, a facsimile or the like in a stacked state and separating the sheets one by one.

[0002]

2. Description of the Related Art There are various types of sheet feeding devices used in copying machines, printers, facsimiles and the like, and one example thereof will be described with reference to FIG. First, this paper feeding device is for feeding recording paper 1 in a copying machine, and is provided with a recording paper base 2 on which a plurality of recording papers 1 are set in a stacked state. An opening 3 is formed at a position slightly rearward from the tip end portion, and a pickup roller 4 is provided below the opening 3. The pickup roller 4 is rotationally driven in a direction (arrow direction) along the paper feeding direction of the recording paper 1 by a driving force from a driving unit (not shown), and a solenoid (not shown) or the like. When driven, it rotates in the up-down direction about the rotation axis of a paper feed roller, which will be described later, and comes into contact with the recording paper 1 (shown by a solid line) and a separation position (shown by a one-dot chain line) away from the recording paper 1. It is provided so that it can move freely. A pressing plate 5 that presses the recording paper 1 is provided above the recording paper base 2 at a position facing the opening 3.

Next, on the leading end side of the recording paper table 2, there is provided a paper feed roller 6 which is rotationally driven in a direction (arrow direction) along the paper feed direction of the recording paper 1 by a driving force from a drive unit. A separation blade 7 that is pressed against the outer peripheral surface of the paper feed roller 6 is provided. The separating blade 7 is formed of a member having a large friction coefficient such as urethane rubber,
The outer peripheral surface of is formed of a rubber member having a larger friction coefficient. The separating blade 7 is attached to the other end of an arm 9 whose one end is rotatably supported by a support shaft 8, and a spring 10 for pressing the separating blade 7 against the outer peripheral surface of the paper feed roller 6. Is interposed between the arm 9 and the fixing member 11 in the copying machine. The pressing force “P” acts on the outer peripheral surface of the sheet feeding roller 6 from the separating blade 7 by the urging force of the spring 10.

In such a structure, when the sheet feeding operation is started, first, the sheet feeding roller 6 and the pickup roller 4 are rotationally driven in the directions of the arrows, respectively, and the pickup roller 4 is moved to the contact position shown by the solid line. Moving. Then, the recording paper 1 on the recording paper base 2 is fed to the nip portion 12 side where the feeding roller 6 and the separating blade 7 are in contact with each other by the pickup roller 4 which moves to the contact position and rotates in the arrow direction. The lowest recording paper 1 passes through the nip portion 12, and the recording paper 1 is held by a pair of conveying rollers (not shown) located downstream of the paper feed roller 6 in the conveying direction of the recording paper 1.

Then, the recording paper 1 which has passed through the nip portion 12
The rotation of the paper feed roller 6 and the pick-up roller 4 is stopped at the timing when the front end of the pick-up roller is clamped by the pair of conveying rollers, and the pick-up roller 4 moves to the separated position shown by the alternate long and short dash line.

[0006]

SUMMARY OF THE INVENTION In a paper feeding device,
The most important problem is to prevent the recording paper 1 from being unfed or double-fed. For the non-feed, the separation blade 7 to the paper feed roller 6
The pressing force acting on the outer peripheral surface of the recording paper 1 is too large, and the recording paper 1 that has entered the nip portion 12 cannot be fed only by the conveying force of the paper feed roller 6, or the leading end of the recording paper 1 is located at the nip portion 12
It occurs because you cannot enter. Therefore, in order to prevent the occurrence of the non-feeding, it is sufficient to reduce the pressing force. However, if this pressing force is too small, the plurality of recording papers 1 will move to the nip portion 1.
Enters 2 and causes double feed.

Therefore, it is not easy to adjust the pressing force so as to prevent both non-feeding and double feeding.

[0008]

The invention according to claim 1 is
A paper feed roller that rotates in a direction along the paper feed direction, a friction member that is pressed against the outer peripheral surface of the paper feed roller, and a paper feed direction that moves to a contact position that abuts the paper. And a pickup roller which is rotated in a direction in which the paper is fed to the nip portion between the paper feed roller and the friction member and is moved to a separated position where the paper is separated from the paper at a predetermined timing thereafter. In a sheet feeding device that separates a plurality of sheets fed by a pickup roller one by one in the nip portion, an auxiliary pressing force that presses the friction member against the outer peripheral surface of the sheet feeding roller with respect to the friction member. When an auxiliary pressing body that applies a force and a pressing force adjusting body that is connected to the pickup roller and moves integrally with the pickup roller are provided, when the pickup roller moves to the contact position. The pressing force adjusting body is brought into contact with the auxiliary pressing body to move the auxiliary pressing body to a position where the application of the auxiliary pressing force is released, and the pressing force adjusting body is moved when the pickup roller moves to the separated position. The auxiliary pressing body is separated from the auxiliary pressing body.

According to a second aspect of the present invention, in the first aspect of the invention, the stopper for regulating the leading end position of the sheet set in the sheet feeding section is also used as an auxiliary pressing body.

According to a third aspect of the invention, in the first or second aspect of the invention, the pressing force of the auxiliary pressing body is applied by the weight of the auxiliary pressing body.

According to a fourth aspect of the invention, in the invention of the first, second or third aspect, an elastic member is interposed between the friction member and the auxiliary pressing body.

[0012]

According to the first aspect of the present invention, when the pickup roller is moved to the contact position and the sheet is fed to the nip portion, the pressing force adjusting body that moves integrally with the pickup roller contacts the auxiliary pressing body. In order to move the lever pressing body to the position where the application of the auxiliary pressing force to the friction member is released,
The pressing force acting on the outer peripheral surface of the paper feed roller from the friction member is reduced, the paper easily enters the nip portion, and the paper that has entered the nip portion is smoothly conveyed by the paper feed roller, so that no paper feed occurs. To be prevented. On the other hand, when the pickup roller is moved to the separating position at a predetermined timing after feeding the paper to the nip portion, the pressing force adjusting body moves to the position separating from the auxiliary pressing body, and the auxiliary pressing force from the auxiliary pressing body is increased. The pressing force applied to the friction member and acting on the outer peripheral surface of the paper feed roller from the friction member is increased, and the occurrence of double feeding in the nip portion is prevented.

According to the second aspect of the present invention, by using the stopper, which is an existing member, as the auxiliary pressing body in the sheet feeding device, it is not necessary to newly provide a dedicated auxiliary pressing body for adjusting the pressing force.

According to the third aspect of the invention, the pressing means for pressing the friction member by the auxiliary pressing body becomes unnecessary.

According to the fourth aspect of the invention, the transmission of vibration from the friction member to the auxiliary pressing body is buffered by the elastic member,
The generation of chattering noise from the contact portion between the friction member and the auxiliary pressing body is prevented.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention described in claim 1 will be described with reference to FIGS. The same parts as those described in FIG. 7 are designated by the same reference numerals, and description thereof will be omitted (the same applies hereinafter). First, this paper feeding device, like the paper feeding device shown in FIG. 7, presses the pickup roller 4, the paper feeding roller 6, and the outer peripheral surface of the paper feeding roller 6 for feeding the recording paper 1 which is a paper. A separating blade 7 which is a friction member is provided. Further, an auxiliary pressing body 13 is provided for applying an auxiliary pressing force for pressing the separation blade 7 to the outer peripheral surface of the paper feed roller 6 with respect to the separation blade 7. The auxiliary pressing body 13 has one end rotatably held by the support shaft 14 and the other end provided so as to come in contact with and separate from the arm 9, and a spring for urging the other end in a direction to press the arm 9. 15 is attached to the support shaft 14.

Next, when the pickup roller 4 is connected to the pickup roller 4 and moves up and down together with the pickup roller 4, the pickup roller 4 moves to a contact position with respect to the recording paper 1 as shown in FIG. As shown in FIG. 2, when the pickup roller 4 moves to a position away from the recording paper 1 while contacting the auxiliary pressing body 13 and moving the auxiliary pressing body 13 to the position where the application of the auxiliary pressing force is released. As shown, a pressing force adjusting body 16 that moves to a position away from the auxiliary pressing body 13 is provided.

In such a structure, when the sheet feeding operation is started, the pickup roller 4 and the sheet feeding roller 6 are rotationally driven in the arrow direction as shown in FIG. 1, and the pickup roller 4 is moved to the contact position. Moving. Then, as the pickup roller 4 moves to the contact position, the pressing force adjusting body 16 rises and contacts the auxiliary pressing body 13, and the auxiliary pressing body 1
3 is rotated to a position where the other end of the auxiliary pressing body 13 is separated from the arm 9. Therefore, the auxiliary pressing force from the auxiliary pressing body 13 applied in the direction of pressing the separation blade 7 against the outer peripheral surface of the sheet feeding roller 6 is released, and the pressing force applied from the separation blade 7 to the outer peripheral surface of the sheet feeding roller 6 is released. the value is less pressure "P _1". For this reason, the recording paper 1 easily enters the nip portion 12, and the recording paper 1 that has entered is smoothly conveyed by the conveying force of the paper feed roller 6, and the non-feeding of the recording paper 1 is prevented.

Next, at the timing when the leading end of the recording paper 1 that has entered the nip portion 12 is clamped by the pair of conveying rollers,
The rotation of the pickup roller 4 and the paper feed roller 6 is stopped, and the pickup roller 4 moves to the separated position as shown in FIG. As the pickup roller 4 moves to the separated position, the pressing force adjusting body 16 descends and separates from the auxiliary pressing body 13, and the other end of the auxiliary pressing body 13 contacts the arm 9 and the auxiliary pressing body 13 The auxiliary pressing force of (3) acts in the direction of pressing the separation blade 7 against the outer peripheral surface of the paper feed roller 6. Therefore, the pressing force "P ₂ " acting on the outer peripheral surface of the paper feed roller 6 from the separating blade 7 becomes a large value (P ₂ >
P ₁ ), the occurrence of double feeding of the recording paper 1 at the nip portion 12 is prevented.

Here, an auxiliary pressing body 13 and a pressing force adjusting body 16 are provided as members for adjusting the pressing force acting on the outer peripheral surface of the paper feeding roller 6 from the separating blade 7, and the pressing force adjusting body 16 is also provided. Since the pickup roller 4 is moved using the movement of the pickup roller 4, the pressing force can be adjusted with a simple structure and at low cost.

Next, an embodiment of the present invention described in claims 2 and 3 will be described with reference to FIGS. In this example,
The stopper 17 that regulates the leading end position of the recording paper 2 when it is set in a stacked state on the recording paper base 2 that is a paper feeding unit is also used as an auxiliary pressing body. First, the stopper 17 is provided so as to be rotatable in the vertical direction with a support shaft 18 as a fulcrum. When the stopper 17 rotates downward, it abuts against the arm 9 so that the separating blade 7 can be moved by its own weight. Abutting portion 1 that presses the outer peripheral surface of the paper feed roller 6
7a is formed.

Further, as shown in FIG. 5, the stopper 17 is provided with a swing piece 19 which is swingable in the vertical direction. The swing piece 19 is supported in an elongated hole 20 which is long in the vertical direction. It is attached to the stopper 17 by inserting the shaft 21.

In such a structure, when the recording paper 1 is set on the recording paper base 2 in a stacked state, the recording paper 1 is recorded by bringing the leading end of the recording paper 1 into contact with the stopper 17, as shown in FIG. The tip position of the paper 1 is regulated. At this time, the contact portion 17a of the stopper 17 which is rotating to the lower position contacts the arm 9, and the weight of the stopper 17 acts as an auxiliary pressing force for pressing the separation blade 7 against the outer peripheral surface of the sheet feeding roller 6. . Accordingly, the pressing force "P _2" is a large value which acts on the outer peripheral surface of the paper feed roller 6 from the separating blade 7.

On the other hand, when sheet feeding is started, the pickup roller 4 and the sheet feeding roller 6 are rotationally driven in the direction of the arrow as shown in FIG. 4, and the pickup roller 4 moves to the contact position with respect to the recording sheet 1. Then, as the pickup roller 4 moves to the contact position, the pressing force adjusting body 16 rises to contact the stopper 17, rotate the stopper 17 upward, and separate the contact portion 17 a from the arm 9. . Here, when the contact portion 17a is separated from the arm 9, the auxiliary pressing force that presses the separation blade 7 acting on the outer peripheral surface of the sheet feeding roller 6 by the weight of the stopper 17 is released. Therefore, from the separation blade 7 to the paper feed roller 6
The pressing force "P ₁ " acting on the outer peripheral surface of the
The recording paper 1 can easily enter the nip portion 12, and the recording paper 1 that has entered can be smoothly conveyed by the conveying force of the paper feed roller 6, and the non-feeding of the recording paper 1 can be prevented.

Next, at the timing when the front end of the recording paper 1 that has entered the nip portion 12 is clamped by the pair of conveying rollers,
The rotation of the pickup roller 4 and the paper feed roller 6 is stopped, and the pickup roller 4 moves to a position away from the recording paper 1 as shown in FIG. Then, as the pickup roller 4 moves to the separated position, the pressing force adjusting body 16 descends and separates from the stopper 17. When the pressing force adjusting body 16 separates from the stopper 17, the stopper 17 rotates downward and the contact portion 17a again contacts the arm 9 so that the pressing force applied from the separating blade 7 to the outer peripheral surface of the sheet feeding roller 6 is increased. P ₂ ″ has a large value (P ₂ > P ₁ ), and the double feeding of the recording paper 1 in the nip portion 12 is prevented.

The pressing force adjusting body 16 is used to make the stopper 1
When 7 is rotated upward, the rocking piece 19 is positioned below the lower edge of the stopper 17 as shown in FIG. 4, and prevents all the recording papers 1 from being fed to the nip portion 12. Therefore, when the pressing force adjusting body 16 is separated from the stopper 17, the lower end edge of the stopper 17 descends to the lower end position of the swing piece 19, and the abutting portion 17 a abuts on the arm 9.

Here, since the stopper 17 which is an existing component is also used as the auxiliary pressing body, it is not necessary to provide a new auxiliary pressing body, and the auxiliary pressing force is separated by utilizing the weight of the stopper 17 itself. Since the blade 7 is applied, it is not necessary to provide a pressing means for applying an auxiliary pressing force, and the pressing force can be adjusted with a simpler structure and at a lower cost.

Next, an embodiment of the invention described in claim 4 will be described with reference to FIG. In this embodiment, similarly to the embodiment shown in FIGS. 3 to 5, the stopper 17 is also used as an auxiliary pressing body, and the protrusion 1 formed on the stopper 17 is used.
A spring 22 as an elastic member is attached to 7b, and the stopper 17 is brought into contact with the arm 9 via the spring 22.

In such a structure, after the pickup roller 4 moves to the position away from the recording paper 1, the pressing force acting on the outer peripheral surface of the paper feeding roller 6 from the separating blade 7 becomes a large value "P ₂ ". At the same time, since the rotation of the paper feed roller 6 is stopped, a minute vibration is generated between the recording paper 1 and the separating blade 7 which are pulled by the conveying roller pair and pass through the nip portion 12, and in such a state, the separating blade 6 When there is a member that directly contacts the arm 7 or the arm 9, a chattering noise is generated at the contact portion. However, the stopper 17 and the arm 9
Since the and are in contact with each other via the spring 22, the vibration from the separation blade 7 is damped by the spring 22,
The generation of chattering noise from the contact portion between the stopper 17 and the arm 9 is prevented.

[0030]

As described above, according to the first aspect of the present invention, a sheet feeding roller that rotates in a direction along the sheet feeding direction, a friction member that is pressed against the outer peripheral surface of the sheet feeding roller, By moving to a contact position for contacting the paper and rotating in a direction along the paper feed direction, the paper is fed to the nip portion between the paper feed roller and the friction member and at a predetermined timing thereafter. In a paper feeding device having a pickup roller that moves to a separating position away from the paper, and separating the plurality of sheets fed by the pickup roller one by one in the nip portion, with respect to the friction member. An auxiliary pressing body that applies an auxiliary pressing force that presses the friction member against the outer peripheral surface of the paper feeding roller, and a pressing force adjusting body that is connected to the pickup roller and moves integrally with the pickup roller. When the pickup roller moves to the contact position, the pressing force adjusting body is brought into contact with the auxiliary pressing body to move the auxiliary pressing body to the position where the application of the auxiliary pressing force is released, and Since the pressing force adjusting body is moved away from the auxiliary pressing body when the sheet is moved to the separating position, when the pickup roller is moved to the contact position and the sheet is fed to the nip portion, the auxiliary pressing body is pressed. Since the body moves to the position where the application of the auxiliary pressing force to the friction member is released, the pressing force applied from the friction member to the outer peripheral surface of the sheet feeding roller can be reduced, and therefore the sheet easily enters the nip portion. At the same time, the paper that has entered the nip section can be smoothly conveyed by the paper feed roller, which prevents the occurrence of non-feeding of the paper, while sending the paper to the nip section. After that, when the pickup roller moves to the separating position, the pressing force adjusting body moves to a position separating from the auxiliary pressing body, and the auxiliary pressing force from the auxiliary pressing body is applied to the friction member, and the friction member feeds the roller. The pressing force acting on the outer peripheral surface of the is increased, and it is possible to prevent the occurrence of double feeding in the nip portion.
Such a pressing force can be adjusted at a low cost by a simple structure in which an auxiliary pressing body and a pressing force adjusting body that is connected to the pickup roller and moves integrally with the pickup roller are provided. Have.

According to the second aspect of the invention, as described above, in the first aspect of the invention, the stopper for regulating the leading end position of the sheet to be set in the sheet feeding section is also used as the auxiliary pressing member, so that in the sheet feeding device. By using the stopper, which is an existing member, as the auxiliary pressing body, there is no need to newly provide a dedicated auxiliary pressing body to adjust the pressing force,
The pressing force can be adjusted with a simpler structure.

As described above, in the invention according to claim 3, in the invention according to claim 1 or 2, the pressing force by the auxiliary pressing body is applied by the weight of the auxiliary pressing body, so that the friction member is provided by the auxiliary pressing body. Since there is no need to provide a pressing means for pressing, the pressing force can be adjusted with a simpler structure.

As described above, according to the invention of claim 4, in the invention of claim 1, 2 or 3, since the elastic member is interposed between the friction member and the auxiliary pressing body, the auxiliary pressing force is applied from the friction member. The transmission of vibration to the body can be buffered by the elastic member, and it is possible to prevent the occurrence of chattering noise from the contact portion between the friction member and the auxiliary pressing body.

[Brief description of drawings]

FIG. 1 is a front view showing a state in which a pressing force acting on an outer peripheral surface of a sheet feeding roller from a separating blade is reduced in an embodiment of the invention according to claim 1;

FIG. 2 is a front view showing a state in which a pressing force applied from the separation blade to the outer peripheral surface of the paper feed roller is increased.

FIG. 3 is a front view showing a state in which recording sheets are set in a stacked state in one embodiment of the invention as claimed in claims 2 and 3.

FIG. 4 is a front view showing a state in which the pressing force applied from the separation blade to the outer peripheral surface of the paper feed roller is reduced.

FIG. 5 is a side view showing a stopper to which a swing piece is attached.

FIG. 6 is a front view showing a state in which a pressing force applied from the separation blade to the outer peripheral surface of the paper feed roller is increased in the embodiment of the invention described in claim 4;

FIG. 7 is a front view showing a conventional sheet feeding device.

[Explanation of symbols]

 1 Paper 2 Feeding Unit 4 Pickup Roller 6 Feeding Roller 7 Friction Member 12 Nip Part 13 Auxiliary Pressing Body 16 Pressing Force Adjusting Body 17 Stopper, Auxiliary Pressing Body 22 Elastic Member

Claims (4)

[Claims] 1. A paper feed roller that rotates in a direction along the paper feed direction, a friction member that is pressed against the outer peripheral surface of the paper feed roller, and moves to a contact position that abuts the paper, A pickup roller that rotates in a direction along the paper feeding direction to feed the paper to the nip portion between the paper feeding roller and the friction member and move to a separating position where the paper is separated from the paper at a predetermined timing thereafter. In a sheet feeding device for separating a plurality of sheets fed by the pickup roller one by one in the nip portion,
An auxiliary pressing body for applying an auxiliary pressing force for pressing the friction member to the outer peripheral surface of the paper feed roller with respect to the friction member, and a pressing force adjusting body connected to the pickup roller and moving integrally with the pickup roller. Is provided, and when the pickup roller moves to the contact position, the pressing force adjusting body is brought into contact with the auxiliary pressing body to move the auxiliary pressing body to a position where the application of the auxiliary pressing force is released, and A sheet feeding device, wherein the pressing force adjusting body is separated from the auxiliary pressing body when the pickup roller moves to the separating position. 2. The sheet feeding device according to claim 1, wherein a stopper that regulates the leading end position of the sheet set in the sheet feeding section is also used as an auxiliary pressing body. 3. The sheet feeding device according to claim 1, wherein the pressing force of the auxiliary pressing body is applied by the weight of the auxiliary pressing body. 4. The sheet feeding device according to claim 1, wherein an elastic member is interposed between the friction member and the auxiliary pressing body.