JPH08188291A - Sheet material conveying device - Google Patents

Abstract

PURPOSE: To maintain conveyance capacity and paper feeding performance even when reduction of wear and a friction force occur by a method wherein the conveyance speed of a paper material conveyed by a conveyance roller is detected and when the detecting conveyance speed is not adjusted to a specified value, a pressure between a conveyance roller pair is regulated. CONSTITUTION: Drive is applied on a conveyance roller 2 to transmit drive to a drive shaft 4 and the conveyance speed of a paper material conveyed by the conveyance roller 2 is set to a proper value responding to a time between a point of time when the drive shaft 4 is started to rotate and a time in which it is detected by a sensor S1 that the forward end of the paper material reaches. When the set conveyance speed is not adjusted to a specified value, a member 9 is steppedly moved with the aid of a motor 7 and the energizing force of a tensile spring 10 is gradually increased and the pressure of a separation roller 3 on the conveyance roller 2 is regulated. As a result, a contact pressure between a pickup roller 1 and the sheet material can be increased and even when wear and a friction force are reduced, conveyance capacity and paper feeding performance are maintainable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet material conveying device for conveying a sheet material by rollers.

[0002]

2. Description of the Related Art In an electronic copying machine, a roller composed of elastic members (rubber, etc.) in various parts such as a pickup roller, a retard roller and a carrying roller is generally used for carrying stacked sheets. in use.

As an example, a paper feed section will be described.

As shown in FIG. 8, the retard roller feeding method is a pickup roller 101 and a pair of conveying rollers 1.
02 and the separation roller 103 form a pair to convey the paper. First, when sheets are stacked on the tray 105 and brought into an operating state, the tray is raised, and an upper surface of the uppermost sheet is stopped at a fixed position by a tray height sensor (not shown).

Further, 107 is a solenoid fixed to the paper feeding section, and its plunger 107a has an arm 108a.
It is connected to. This arm 108a is an arm 108
b, 108c, and 108d, respectively, and the tip of the arm 108d is configured to support the arm 104 supporting the pickup roller 101 so that the arm 104 can be moved up and down in response to the operation of the plunger 107a. There is. The pickup roller 101 is rotatably attached at a fixed center to an arm 104 that is rotatably supported coaxially with the rotation axis of the transport roller 102.
The arm 104 is configured to rotate in the vertical direction by 8d.

When a current flows through the solenoid 107, the plunger 107a is attracted and the arm 108a is pulled, so that the arms 108b, 108c, 108d and the arm 104 are interlocked, and the pickup roller 101 is moved from above the uppermost paper 106. Pull it up so that it will not be fed. When the current flowing through the solenoid 107 is cut off, the weight of the pickup roller 101 causes the arm 104 to rotate and drop onto the uppermost paper 106.

When the next rotating pickup roller 101 descends onto the paper, the uppermost paper 10 in the tray 105
6 and the paper is conveyed in the nip direction of the separation roller 103 and the conveyance roller 102. The conveying roller 102 receives the driving force in the counterclockwise direction and the separating roller 103 receives the driving force in the counterclockwise direction. However, since the separating roller 103 and the driving source have the torque limiter 113 shown in FIG. 1
When there is no paper between 02 and 103, or when there is only one paper, the torque limiter setting torque is defeated by the rotation torque due to the conveyance roller or the conveyance of the paper and the conveyance roller 102.
Or it follows the paper and rotates. This FIG. 9 is seen from the direction A of FIG.
3 schematically shows the relationship between the torque limiter 113 and the torque limiter 113.

Separation / conveyance roller 10 having such a structure
2 to 103 nip from pickup roller 101 to 2
As the sheets of paper are conveyed, the uppermost paper is conveyed by the conveyance roller 1.
However, the separation roller having a friction coefficient larger than that between the sheets except the uppermost sheet is rotated counterclockwise by the torque limiter, and only one sheet is conveyed to the downstream conveyance roller 112.
Will be sent to.

[0009]

Here, the pickup roller 101, the conveying roller 102, and the separating roller 10 are used.
In No. 3, the frictional force is reduced during use due to abrasion and the adhesion of paper dust, and as a result, the conveyance force becomes insufficient and the uppermost paper 106 cannot be fed, which causes paper jam.

As described above, since rubber rollers are used everywhere inside the electronic copying machine, there is a problem that the frictional force is reduced due to wear or the like as the durability advances.
Eventually it will be exchanged.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems. An object of the present invention is to reduce abrasion and frictional force in a sheet material conveying section using a rubber roller. Still, it is to maintain the carrying capacity and the paper feeding performance.

In order to achieve the above object, the present invention has a sheet material conveying device using a pair of rollers, and has a detecting means for detecting the conveying speed of the sheet material and an adjusting means for adjusting the pressure between the conveying roller pair. However, for example, when the transport speed is reduced, the pressure between the pair of transport rollers is increased.

[0013]

According to the present invention, even if the frictional force is reduced due to abrasion of the rubber roller or the like, it is possible to maintain the carrying ability and the paper feeding ability.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view of the conveying device. here,
A schematic configuration of a carrying device according to the present embodiment will be described with reference to FIG. 1. 1 is a pickup roller for sending out the uppermost stacked paper, 2 is a carrying roller, and 3 is a driving direction opposite to the carrying direction. The separating roller that rotates in the reverse direction only when receiving and double feeding, and the conveying roller 2 and the separating roller 3 form a separating and conveying roller pair 5. Reference numeral 4 denotes a drive shaft that rotates about a fixed center that drives the transport roller 2, and is ON-OFF controlled by an electromagnetic clutch (not shown). 16 is a belt for transmitting the drive to the pickup roller 1, and 6
Is a lever that mounts the pickup roller 1 rotatably around a shaft 4, and is urged by a tension spring 10 in the sheet S stacking direction. This tension spring 10
Is engaged with one end of a member 9 which is guided so as to be movable in the horizontal direction, a tap hole is provided in the other end of the member 9, and a screw of a motor 7 fixed to a sheet feeding device is screwed into this hole. The rotating shaft is engaged.

Numeral 8 is a limit switch fixed to the sheet feeding device for detecting the contact of the member 9 with the motor 7 and controlling the rotation of the motor. Similarly, reference numeral 11 is a lever for rotatably mounting the separation roller 3 around a fixed central shaft 17, which creates a nip pressure of the separation conveyance roller 5 by a tension spring 15. The tension spring 15 and the motor 12 (in the vertical direction)
Like the tension spring 10 and the motor 7, it is engaged with a member 14 which is movably guided. The motor 12 is fixed to this paper feeding device like the motor 7. Reference numeral 13 denotes a limit switch fixed to the paper feeding device for detecting that the member 14 contacts the motor 12 and controlling to stop the rotation of the motor. Reference numeral 18 denotes a tray on which paper is loaded and which can be raised and lowered by means not shown. Further, the initial setting positions of the members 9 and 14 are set so as to be a predetermined distance from the limit switch 8 and the limit switch 13, respectively, and the initial setting positions are automatically set by pressing individual predetermined buttons or the like. I'm supposed to come back. S1 is a sensor for detecting the success or failure of the paper conveyance by the pickup roller 1 and a conveyance timing, and S2 and S3 are sensors for detecting the success or failure of the paper conveyance by the separation / conveyance roller pair 5 and the conveyance timing. The pickup roller 1 performs a pickup operation via a link mechanism 19 by a solenoid SL1 fixed to the paper feeding device.

The operation procedure will be described. First, when sheets are stacked on the tray 18 and brought into an operating state, the tray is raised, and an upper surface of the uppermost sheet is stopped at a fixed position by a tray height sensor (not shown). At this time, the solenoid SL1 is on, and the pickup roller 1 is not in contact with the paper.
When the carrying operation starts, the solenoid SL1 turns off.
Then, the picked-up roller 1 that has descended rotates, and the uppermost sheet is conveyed in the nip direction of the separation and conveyance roller pair 5.
The conveying roller 2 receives the driving force in the counterclockwise direction and the separating roller 3 receives the driving force in the counterclockwise direction, but the separating roller 3 has a torque limiter between it and the driving source, and the slip start torque is the rollers 2, 3 Since it is set to be smaller than the rotation torque due to μ between μ and μ with paper, when there is no paper on the normal rollers 2 and 3, or when there is only one paper, it rotates following the transport roller 2 or paper. To do.

When two sheets of paper are conveyed from the pick-up roller 1 to the nip of the separation / conveyance roller pair 5 having such a structure, the uppermost paper is conveyed by the conveying roller 2, but other than the uppermost paper. Means that the separation roller 3 having a friction coefficient larger than that between the sheets rotates counterclockwise by the torque limiter,
Only one sheet is sent to the downstream transport roller.

Here, a control drive signal is issued from the paper feed main body to an electromagnetic clutch (not shown) that transmits drive to the drive shaft 4, and the sensor S1 detects the arrival of the leading edge of the paper from the time when the drive shaft 4 starts to rotate. It is possible to know the degree of delay in sheet feeding by the pickup roller 1 from the time required for the sheet feeding, and the delay in sheet feeding by the separation roller pair 5 from the time required for the leading edge of the sheet to reach S3 after passing the sensor S2. You can know the degree of

From this, the sensor S1 is caused by wear of the roller or the like.
When the time when the paper arrives at the paper is delayed, for example, when this delay is within 50% of the margin time until the paper jams, the motor 7
Does not operate, and when it exceeds 50%, the motor 7 is rotated by a predetermined angle to horizontally move the member 9 to the left in the drawing. Thus, by gradually moving the member 9 by the motor 7 (FIG. 2), the urging force of the tension spring 10 can be gradually increased, and as a result, the contact pressure between the pickup roller 1 and the paper can be increased. it can. At this time, it is desirable that the unit movement amount of the member 9 is made small so that the pressure of the pickup roller 1 can be finely adjusted. However, if it is too small, the adjustment takes too much time, and this is a balance with the time required for this adjustment. It is necessary to determine appropriately.

As a result, the conveyance delay is improved by increasing the conveyance force against the conveyance delay caused by the abrasion of the pickup roller 1 and the reduction of the frictional force.

Further, when there is a delay in the arrival time from the sensor S2 to the sensor S3 position, the motor 12 is rotated by a predetermined angle by the same motor control method as described above, and the member 1 is rotated.
By gradually moving 4 downward in the figure (FIG. 3), the nip pressure of the separation / conveyance roller pair 5 can be increased and the conveyance delay can be improved. And the above-mentioned member 9 or 1
When 4 reaches the limit switch 8 or 13, it is displayed that it is time to replace the roller. This flow is shown in FIG. Here, when not feeding, readjustment is repeated until the limit switch is activated until the paper can be fed.However, if the paper cannot be fed even after repeating the predetermined number of times, the paper feeding operation is performed. You may cancel and display an error message.

FIG. 5 is a graph showing the paper feed separable area of the separation / conveyance roller pair 5. Here, the vertical axis represents the separation roller pressure P, which is determined by the tension spring 15. The horizontal axis represents the operating torque T of the separation roller 3, which is the torque required for the separation roller 3 to follow. In addition, a straight line L _u that forms the upper limit of the paper feed separable area
Is L _u = T / μ ₂ · R, and the straight line L ₁ forming the lower limit is L _l =
T / μ ₁ · R. Here, μ ₁ is the friction coefficient between the transport roller 2 and the paper, μ ₂ is the friction coefficient between the paper and R, and R is the radius of the separation roller 3.

Here, the operating torque T of the separation roller 3 is shown in FIG.
As described above, the initial setting position of the member 14 is a position near the center of the paper feed separable region where the separation roller pressure P is approximately (Ps + Pm) / 2, and the position where the limit switch 13 operates. (FIG. 6), the separation roller pressure P is set to Pm.

However, when the paper dust adheres to the roller or the frictional force is reduced due to abrasion, μ ₁ becomes smaller, so that the inclination of L ₁ becomes large as shown by the dotted line in FIG. It shifts from near the center of the feasible region.

At this time, the separation roller pressure P can be increased little by little by controlling the motor 12 by the above method.
Since it is possible to maintain the position near the center of the paper feed separable area, it is possible to achieve high stability of the paper feed separation performance.

When the paper type is changed or the rollers are replaced, double feeding may occur if the roller pressure is kept high. Therefore, as shown in FIG. 7, the limit switches 20, 21 are provided near the tip of the shaft so that the member 9 and the member 14 are not separated from the threaded shaft of the motor 7 or the motor 12.
When the tray is opened / closed or a double feed is detected, the members 9 and 14 are individually moved by rotating the motor 7 and the motor 12 in the forward and reverse directions to increase and decrease the roller pressure. Alternatively, a desired roller pressure may be adjusted automatically or automatically by a user or a service person pressing a predetermined button or the like when the paper type is changed or for maintenance.

Further, a stepping motor is used as the motor 7 or the motor 12, and the position of the member 9 or the member 14 is controlled by the pitch of the screw cut on the motor shaft and the rotation angle of the motor, whereby the limit switches 8, 13, 20, 21 are controlled. May be eliminated. At this time, the member 9 or the member 14
The initial setting position of is set to a predetermined distance from the tip of the motor 7 or the motor 12, for example. Further, a cam may be used to change the tension amount of the tension spring. At this time, limit sensors are provided at the initial setting positions of the cams.

As described above, even for a roller whose surface frictional force has decreased due to abrasion or the like, it is possible to prevent conveyance delay or paper feeding failure by increasing the pressure applied to the roller correspondingly. Further, it is needless to say that this can be applied to a method other than the retard, and can also be applied to a conveying roller.

[0030]

As is apparent from the above description, according to the present invention, in the sheet material conveying device using the roller (rubber roller), the frictional force which is unavoidable when the rubber roller is used is lowered. Even in such a case, by providing the means for increasing the contact pressure of the roller, it is possible to obtain the effect of maintaining the conveying ability and the paper feeding performance.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a configuration of a sheet material conveying device according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a state of a pickup roller pressure increasing operation in the embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view showing a state of a pressure increasing operation of the separation roller in the embodiment of the present invention.

FIG. 4 is a flowchart showing a processing procedure in the embodiment of the present invention.

FIG. 5 is a graph showing a range of pressure change in an example of the present invention.

FIG. 6 is a vertical cross-sectional view showing the state at the time of the pressure increasing operation of the separation roller in the embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view showing a structure capable of returning to the initial position in the embodiment of the present invention, which is capable of normal and reverse rotation.

FIG. 8 is a vertical cross-sectional view of a conventional transfer device.

FIG. 9 is a schematic view of a pair of separation / conveyance rollers.

[Explanation of symbols]

 1 Pickup Roller 2 Conveyance Roller 3 Separation Roller 4 Drive Shaft 5 Separation Conveyance Roller Pair 6 Pickup Pressure Lever 7 Motor 8 Limit Switch 9 Member 10 Tension Spring 11 Separation Roller Pressure Lever 12 Motor 13 Limit Switch 14 Member 15 Tension Spring 16 Drive Belt 17 Axis 18 Tray 19 Link mechanism 20,21 Limit switch S1, S2, S3 Pass sensor SL1 Solenoid S Sheet material

Claims (2)

[Claims] 1. A sheet material conveying apparatus using a pair of rollers, a detecting means for detecting a conveying speed of a sheet material sent by the conveying rollers, an adjusting means for adjusting a pressure between the conveying roller pairs, and the detecting means. A sheet material conveying device comprising a control means for adjusting the pressure between the pair of conveying rollers when the conveying speed detected by the means does not reach a constant value. 2. The sheet material conveying apparatus according to claim 1, wherein the pressure between the pair of conveying rollers can be adjusted automatically or manually when the opening / closing of the tray or double feeding is detected. .