JP2514530Y2 - Paper transport device - Google Patents

Description

[Detailed description of the device] [Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device that conveys originals or sheets toward a predetermined position in a copying machine or an image reader and conveys the sheets one by one.

[Prior art]

In devices that transfer and record original images on paper, such as copiers,
It is necessary to take out the uppermost or the lowermost one of a plurality of sheets placed on the sheet feeding tray one by one, and feed the sheets to the image transfer position without skewing. Further, in an automatic document feeder that sequentially automatically feeds documents placed on a document tray onto a platen of a copying machine, in an automatic document feeder, the originals on the tray are taken out one by one and the copying machine is operated without skewing. Need to be fed on the platen. Therefore, in the paper feeding device that takes out the sheets (hereinafter, including the originals) one by one and expedites them,
One is provided with a separation feeding roller composed of a pair of rollers rotating in a feeding direction and the other rotating in a direction in which a following sheet is retreated, and a registration roller arranged on the downstream side of the separation feeding roller. The feed roller separates the sheets on the feed tray one by one and feeds them in the feeding direction so that the leading edge of the sheet elastically abuts against the registration roller, and the paper is bent a predetermined amount on the upstream side of the registration roller. Is generated, the posture in which the sheet is conveyed is corrected so that the sheet is not obliquely fed, and thereafter, the sheet is opposed to the platen or the image transfer position direction at an appropriate timing of the copying operation. are doing.

[Problems to be solved by the device]

In the above-described paper transporting device, the transporting path up to the platen or the image transfer position has a transporting path that bends and transports the paper in order to make the structure of the device or reverse the front and back of the paper. There is one provided. However, in the case where such a curved conveyance path is provided, a collision sound that collides with the wall surface of the bending portion when the paper enters the bending portion, and a trailing end that bounces when the sheet exits the bending portion A collision noise was generated, which was a source of abnormal noise. This abnormal noise tends to increase as the paper thickness increases. Therefore, in the past, in the case of thick paper, the conveyance speed was manually switched to a low speed to reduce noise. However, in the case of manually switching the paper transport speed as described above, the operation is troublesome, and thus the switching operation is not actually performed, and there is a problem that it is not useful for preventing abnormal noise. SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet conveying device capable of surely reducing abnormal noise associated with sheet conveyance.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a separating means for separating sheets one by one, a registration roller arranged on the downstream side of the separating means, and a conveying path for conveying the paper from the separating means to the registration roller. And a loop forming section for the sheet provided in the middle of the conveyance path, the tip of the sheet separated by the separating unit is abutted against the registration roller, and a loop is formed in the loop forming section to change the posture. In a sheet conveying device configured to feed out a sheet after correction, a registration sensor for detecting a sheet provided immediately before the registration roller, a deflection sensor for detecting a deflection of the sheet in the loop forming unit by a predetermined amount or more, and Deflection time measuring means for measuring the time from the detection of the sheet by the registration sensor to the detection of the deflection of a predetermined amount or more by the deflection sensor; Based on the time measured by the time measuring means, the thickness of the paper is divided into at least two stages and the thickness judgment means is determined. In the case of thick paper, the thickness of the paper is thinner than that according to the judgment result of the thickness judgment means. In order to make the sheet conveying speed slower than that in the above case, a speed control means for switching and controlling the sheet conveying speed of the registration rollers is provided.

[Action]

According to the above configuration, the thickness of the sheet is determined in at least two stages based on the time measured by the deflection time measuring unit, and the sheet conveyance speed is switched and controlled according to the determination result. For example, when the thickness of a sheet is divided into a thick sheet and a thin sheet, the transport speed of the thick sheet is slower than that of the thin sheet.

【Example】

Hereinafter, a detailed description will be given based on an embodiment in which the present invention is applied to a double-sided document automatic feeder. FIG. 1 is a sectional view showing an embodiment of a double-sided document automatic feeding device to which the present invention is applied. The device 1 is roughly divided into a document tray 2 and one by one. The feeding unit 3 for feeding, the feeding unit 4 for feeding the fed originals one by one to correct the posture facing the feeding direction, and feeding the originals after the image processing for feeding to the predetermined position of the platen P. Alternatively, it is composed of a reverse discharge unit 5 which reverses the front and back and guides the platen P toward the predetermined position again, and a discharge tray 6 on which discharged documents are placed. The paper feed unit 3 includes a pickup roller 7, an empty sensor 8, a separation roller 9 (separation means), and a registration sensor 1.
0, a flexure sensor 26, a pickup roller 7, and a motor M1 as a power source for the separation roller 9, and the originals placed on the paper feed tray 2 are taken out by the pickup roller 7 from the bottom by several sheets. Only the lowest document is separated by the separating roller 9 and sent to the space 11 (loop forming part) having a large loop margin. Here, the original document whose direction has been changed along the outer guide plate 12 reaches the nip point between the registration roller 14 and the pinch roller 15 of the conveying unit 4 through the linear guide unit 13. The conveying unit 4 includes the registration roller 14 and the pinch roller 15, a wide conveying belt 16, a driving roller 17 and a driven roller 18 for rotating the conveying belt 16, and a conveying belt.
A plurality of pinch rollers 19 for tensioning 16 on the upper surface of the platen P
The original fed to the entrance of the registration roller 14 is fed in the direction of the platen P by the rotation of the registration roller 14 while being pressed against the registration roller 14 and the pinch roller 15. Then, the sheet is conveyed onto the platen P by the conveyor belt 16 which starts rotating simultaneously with the registration roller 14. At this time, since the registration sensor 10 is turned on until the trailing edge of the document is sent out from the position of the registration sensor 10, the control unit, which will be described later, operates the registration roller 14
The number of pulses applied to the motor M2, which is the power source of the drive roller 17 and the registration roller 14, is counted from the timing when the drive roller 17 starts to rotate to the timing when the registration sensor 10 is turned off by the passage of the trailing edge of the document. , According to the count value, classifies the document size into the standard document size. Then, when copying only one side, the motor M2 is stopped when a pulse corresponding to the distance LO from the position of the registration sensor 10 to the predetermined position A on the platen P is applied to the motor M2. As a result, the original is placed on the platen P.
Is set to a predetermined position A. The registration roller 14 is a conveyor belt 16 and a drive motor.
The registration clutch G is interposed between M2 and the conveyor belt.
The rotation of the registration roller 14 is not stopped while the 16 is rotating. Next, the reversing discharge unit 5 is the reversing roller 20.
And driven rollers 21a, 21b pressed against this, switching claws 22 for backward feeding in the direction of the conveyor belt 16 with the front and back of the document reversed, a sensor for ejecting paper 23, a sensor for determining the stop timing at the time of backward feeding 24, a discharge roller 25, and a motor M3 as a power source for the reversing roller 20, and the reversing roller 20 discharges the document conveyed in the discharge direction by the conveyance belt 16 when the image processing on one side of the document is completed. Is conveyed in the direction. At this time, when the switching claw 22 is as shown in the figure, the sheet is ejected to the sheet ejection tray 6 by the sheet ejection roller 25. However, when the switching claw 22 is switched to the reverse feeding side, it is guided in the direction of the driven roller 18 of the transport belt 16 and is set to the predetermined position of the platen P again by the reverse rotation of the transport belt 16. On the other hand, at the time of double-sided copying, in order to arrange the discharge order of the originals, the originals are passed once over the platen P and the reverse discharge unit 5 reverses the front and back of the originals.
By setting it at the predetermined position A, one-sided copying is performed. After that, the front and back of the document are reversed by the reversal discharge unit 5 and set at the predetermined position A again, and the remaining one side is copied,
After that, the switching claw 22 of the reversal discharge unit 5 is switched to the state shown in the figure, and the sheet is discharged to the sheet discharge tray 6. Here, the flexure sensor 26 will be described in detail with reference to the enlarged cross-sectional view of FIG. 2. The flexure sensor 26 has a lever 26a projecting from the space 11 on the upstream side of the registration roller 14 and the lever 26a. And a switch 26b that is turned on when the document is rotated counterclockwise by a predetermined angle, and the control unit described later includes a bending time measuring unit, a thickness measuring unit, a thickness measuring unit, and a speed control unit. The timing operation is started from the timing when the leading edge of the document is detected by the registration sensor 10, the document reaching the nip point of the registration roller 14 is in a predetermined bending state, the lever 26a is rotated by a predetermined angle, and the switch 26b is turned on. If so, the timing operation is stopped at this on-timing (deflection time measurement), the paper thickness is divided into at least two levels based on the time of this measurement result (thickness measurement), and the judgment result Correspondingly adapted to control switching of the document transportation speed (speed control). FIG. 3 is a block diagram showing the structure of a control unit for controlling the conveyance of a document according to the present invention. This control unit is specifically configured by the microcomputer 30.
The microcomputer 30 receives the output signals of the empty sensor 8, the registration sensor 10, the paper discharge sensor 23, the sensor 24 for detecting the stop timing, and the deflection sensor 26, as well as the motors M1, M2, Clock pulses φ1, φ2 that are the reference for the pulses PM1, PM2, PM3 applied to M3
Has been entered. Further, as output signals, pulses applied to a motor M1 for rotating and driving the separation roller 9 and the like of the sheet feeding unit 3, a motor M2 for rotating the conveyor belt 16, and a motor M3 for rotating the reversing roller 20. PM1 to PM3, an ON signal RCL to the registration clutch G for transmitting the rotation of the motor M2 to the registration rollers 14, a drive signal SD to a solenoid (not shown) for switching the switching claw 22, etc. are output. . Further, inside the microcomputer 30, a timer T (deflection time measuring means) for measuring the time until the document is in a predetermined bending state is provided. The operation of switching the document conveyance speed will be described below with reference to the flowchart of FIG. First, when a document is set on the paper feed tray 2, the empty sensor 8 detects the document and the document can be automatically fed (step S1). In this state, when the copy start switch is pressed on the image processing apparatus body (step S2),
The microcomputer 30 sends a reference transport speed SPO to the motor M1.
A pulse PM1 having a cycle corresponding to is input to rotate the motor M1 (step S3). As a result, the pick-up roller 7 and the separation roller 9 start to rotate, several lower originals of the originals placed on the paper feed tray 2 are taken out, and the lowermost original of these several originals is separated. Separated by roller 9. This state is shown in FIG. The one original ORG separated in this way is fed toward the space 11 as the pickup roller 7 and the separation roller 9 rotate. When the leading edge passes the position of the registration sensor 10, the registration sensor 10 is turned on (step S4), so that the microcomputer 30 sets the timer T for measuring the document bending time based on the output signal of the registration sensor 10. Start (step S5). Then, it is determined whether or not a fixed time has elapsed since the motor M1 was started to rotate (step S6). If the fixed time has elapsed, the motor M1 is stopped (step S6).
7). Then, it is checked whether or not the bending sensor 26 is turned on (step S8), and if not turned on, the process returns to step S6. In this manner, before the motor M1 is stopped, the leading edge of the document ORG sent to the space 11 elastically collides with the registration roller 14 and the conveyance in the conveyance belt direction is stopped. Due to this restraint, the original ORG is bent. Then, when the amount of this bending exceeds a predetermined amount, the top of the bending causes the lever 26a of the bending sensor 26 to rotate counterclockwise. As a result, the switch 26b of the deflection sensor 26 is turned on (step S8). This state is shown in FIG. 5 (b). When the bending sensor 26 is turned on, the microcomputer 30 stops the bending time measuring timer T (step S9), and the thickness of the original ORG is divided into at least two kinds, that is, thick and thick, according to the time of the measurement result. Determine separately. (Step S10). In other words, a thin document takes a short time to reach a predetermined bending state, and a thick document takes a long time to reach a predetermined bending state. Determine the thickness of. As a result of this judgment,
When the original ORG is thick, the speed control means switches the speed parameters of the motors M1 to M3 so that the conveyance speed is slightly faster than the reference speed SPO (step S1).
1). On the other hand, when the original ORG is thin, the motor M1 is set so that its transport speed is slightly slower than the reference speed SPO.
Switch the speed parameter of ~ M3 (step S12). After this, the microcomputer 30 sets the registration roller 14
The registration clutch G is turned on and the motor M2 is further rotated in order to convey the original document stopped by the direction of the conveying belt (step S13). The rotation speed of the motor M2 at this time is according to the result of the document thickness determination. After that, the motors M1 to M3 are rotationally driven at a speed according to the result of the document thickness determination until the empty sensor 8 detects that there is no document in the paper feed tray 2. When a new document speed is placed on the paper feed tray 2, the thickness of the document is determined again in the same manner, and the rotation speeds of the motors M1 to M3 are determined based on the determination result. In this case, the thickness of the document may be determined each time the document passes through the registration sensor 10. Further, the flexure sensor 26 is not limited to a mechanical one using a lever, but may be a transmissive flexure sensor 28 including a light emitting element 27a and a light receiving element 27b as shown in FIG. 6 (a). Alternatively, as shown in FIG. 6 (b), a reflection type deflection sensor 29 having a light emitting element and a light receiving element incorporated therein may be used. By changing the feeding speed according to the thickness of the original in this way, that is, if the original is thin, it is faster than the reference speed, and if the original is thick, it is slower than the reference speed. It is possible to reduce noise such as a collision sound when the vehicles collide. Specifically, in the automatic document feeder of FIG. 1, since the bent portions shown in FIG. 1 are present, the noise when passing through these portions can be automatically reduced.

[Effect of device]

As described above, according to the present invention, a separating unit that separates sheets of paper one by one, a registration roller disposed on the downstream side of the separating unit, and a conveying path that conveys the sheet from the separating unit to the registration roller, A loop forming unit for the sheet provided in the middle of the conveying path is provided, and the leading end of the sheet separated by the separating unit is abutted against the registration roller to form a loop in the loop forming unit to correct the posture. In a sheet conveying device configured to feed out a sheet later, a registration sensor provided immediately before the registration rollers for detecting the sheet, a deflection sensor for detecting a deflection of the sheet at a predetermined amount or more in the loop forming unit, and the registration sensor. Deflection time measuring means for measuring the time from when the sheet detects a sheet to when the deflection sensor detects a predetermined amount or more of deflection, and the deflection time. Based on the time measured by the setting means, the thickness of the paper is divided into at least two stages and the thickness judgment means is determined. Since the speed control means for switching and controlling the paper transportation speed of the registration roller is provided so that the paper transportation speed becomes slower than the case, it is possible to automatically and surely reduce the abnormal noise accompanying the transportation of the paper. it can.

[Brief description of drawings]

1 to 5 are views showing an embodiment of the present invention. FIG. 1 is a sectional view of the entire apparatus, FIG. 2 is an enlarged sectional view of a feeding section and a conveying section, and FIG. 3 is a control. FIG. 4 is a block diagram showing the structure of the section, FIG. 4 is a flowchart showing a control means for switching the conveyance speed, FIG. 5 is an explanatory view for explaining the operation of the flexure sensor, and FIG. 6 is another embodiment of the flexure sensor. It is a block diagram shown. 1: Automatic document feeder 2: Paper feed tray 3: Feeding section 4: Conveying section 5: Reverse ejection section 6: Paper ejection tray 14: Registration roller 10: Registration sensor 26: Deflection sensor 30: Microcomputer M1, M2 :motor

Claims (1)

(57) [Scope of utility model registration request] 1. A separating means for separating the sheets one by one, a registration roller arranged on the downstream side of the separating means, a conveying path for conveying the paper from the separating means to the registration rollers, and a conveying path for the conveying path. A loop forming section for the sheet provided on the way, and the leading end of the sheet separated by the separating unit is abutted against a registration roller, a loop is formed in the loop forming section and the posture is corrected, and then the sheet is fed out. In the paper transporting device configured as described above, a registration sensor that detects the paper provided immediately before the registration roller, a bending sensor that detects the bending of the paper in the loop forming unit by a predetermined amount or more, and the registration sensor detects the paper. After that, the bending time measuring means for measuring the time until the bending sensor detects bending of a predetermined amount or more, and the bending time measuring means, According to the result of this thickness determination means, the thickness determination means for determining the thickness of the paper in at least two stages based on the set time is compared with the case of thicker paper than that of thinner paper. And a speed control means for switching and controlling the paper transportation speed of the registration roller so that the paper transportation speed becomes slower.