JPH09301577A - Paper sheet conveying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To release conveying force of a conveying roller catching a paper sheet when a slant roller draws a paper sheet. SOLUTION: A paper sheet conveyed one by one from a paper feeding unit is caught by an inlet roller 25, turned at a turn part 26 at an angle of 90 deg., and fed to a horizontal conveying part 27. At this time, a solenoid 17 is on, and a slant sponge roller 15 is separated. After the rear end of the paper sheet passes the inlet roller 25, the solenoid 17 is turned off before the tip of the paper sheet is caught by a roller 14, and the slant sponge roller 15 is pressurized. Simultaneously, the conveying roller 19 is separated upward. Since only conveying force of the slant sponge roller 15 is applied to the paper sheet, diagonal conveying force is easily applied to it, and the front end is moved to the position along the side fence. By this mechanism, the position of the front end of the paper sheet is regulated, held in the constant position, and laterally registered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device, and more particularly to a sheet width direction correcting mechanism of a sheet feeding device in an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art As a method for regulating the position (registration, skew correction) of sheets that are separated and conveyed one by one from a sheet feeding unit or the like, a skew roller (pair) slightly inclined with respect to the sheet conveying direction is used. Conventionally, there is a method in which a sheet is brought into contact with the sheet to generate a sheet conveying force in a direction perpendicular to the sheet conveying direction, the sheet is moved in that direction, and the sheet end portion is made to lie along a reference surface provided on the side of the sheet. In the case of this type of transporting device, after the attracted paper strikes the reference surface, the skew roller and the paper need to slip with respect to the transport in the direction perpendicular to the transport. If the conveyance force is too large, the skew roller and the paper cannot slip and buckle, causing a paper jam. Therefore, a very large carrying force cannot be applied. Conversely, in order to bring the paper to the reference surface,
The conveying force of the skew roller must be larger than the sheet conveying resistance. If it is smaller than the conveyance resistance, there is a problem that the paper cannot be pulled close.

As described above, it is necessary to set the conveying force within the optimum range such that the sheet slips at the time of abutting and the conveying resistance is not lost. Actually, sponge rollers are often used. If the paper transport path is flat,
The conveyance resistance does not greatly depend on the paper quality, but when a curved portion is provided in the conveyance path for reasons such as compactness of the device,
The conveyance resistance changes according to the paper thickness. Therefore, if the conveying force of the skew roller is constant (if it cannot be varied), there is a possibility that buckling jam, defective sheet position regulation, etc. may occur depending on the thickness of the sheet.

The pressure applied to the skew rollers has been described above, but hereinafter, the transport rollers other than the skew rollers will be described. When the sheet is moved by the skew roller, it is necessary to suppress the resistance of the transport rollers other than the skew roller to be low in order to smoothly transport the sheet and move the sheet in the right angle direction. For this reason, conventionally, a steel ball or the like is used to provide a conveying force while suppressing the conveying resistance when the skewed rollers are brought close to each other. However, especially when the paper thickness is thin, the conveyance resistance is too large to pull the trailing edge of the paper close to each other, and only the leading end of the sheet is slanted into the reference surface, which may cause a jam of the leading edge. It was On the contrary, especially when the paper thickness is thick,
This carrying force was too small, and the paper and the carrying roller slipped, causing a drop in the carrying speed, and during continuous paper feeding, the paper distance disappeared at this position and the sensor could not detect it, resulting in a jam.

[0005]

The invention according to claim 1 is to solve the above-mentioned problems, and when the skew roller is moving the sheet, the sheet is eaten. The carrying force of the carrying roller is released. The skew roller may be in a pressurized state all the time, but if this is the case, the skew roller is moved from the leading edge of the sheet to be eaten, and therefore, particularly in the case of a long sheet, the above-mentioned slanting is likely to occur. Therefore, in the case of long paper, the skew roller is released, for example, by moving it upward, and pressure is applied as close as possible to the center of the paper. It is troublesome to control the release-pressurization of the skew rollers and the release-pressurization of the other transport rollers. According to the invention of claim 2, each of the rollers is troublesome to be turned on by interlocking the release-pressurization-
This is a simple OFF control.

According to a third aspect of the present invention, the optimum conveying force is obtained by arranging the pressing force of the skew roller to be variable. When the paper is thick, it is necessary to set the pressure to be large, and when the paper is thin, it is necessary to set the pressure to be small. According to the invention of claim 4, the pressing force is set according to the sheet thickness, and the optimum conveying force is applied to any sheet without inputting the sheet thickness information and setting the pressing force easily and cumbersomely. It is what

Paper characteristics change with temperature and humidity. Especially when the humidity is high, the stiffness of the paper disappears and when the reference surface is struck,
Buckling jamming becomes easier. Therefore, the buckling jam may occur depending on the temperature and humidity conditions even if the optimum conveying force for the sheet thickness is given. According to claim 5, a temperature / humidity detection mechanism is provided inside or in the vicinity of the transfer device, and the optimum transfer force without buckling jam is obtained by changing the pressing force of the skew roller based on the detection result. It is a thing.

[0008]

According to a first aspect of the present invention, the sheets which are separated and conveyed one by one are brought close to each other by a skew roller and the ends are aligned with a reference plane, whereby the position of the sheets is regulated to a constant value. In the conveying device of the method described above, when the skew roller is moving the sheet, the conveying force of another conveying roller that is eating the sheet is released.

According to a second aspect of the present invention, in the first aspect of the invention, the skew roller is configured to be capable of pressure-non-pressurizing fluctuation, and when the skew roller is under pressure, another sheet is eaten. It is characterized in that the feeding roller that has been taken in is released, and that when the skew feeding roller is not pressed, the feeding roller is interlocked so as to be pressurized.

According to a third aspect of the present invention, the sheet is separated and conveyed sheet by sheet by a skew roller, and the end portions are aligned with the reference plane, whereby the sheet position is regulated to a constant value. In the above, it is characterized in that the pressing force of the skew roller can be varied.

The invention of claim 4 is characterized in that, in the invention of claim 3, the pressing force of the skew roller is switched to a plurality of stages by previously inputting the thickness of the sheet to be separated and conveyed. is there.

According to a fifth aspect of the present invention, in the third aspect of the invention, a temperature / humidity detection mechanism is provided inside or near the transfer device,
It is characterized in that the pressing force of the skew roller is switched in a plurality of stages based on the detection result.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining an example of an image forming apparatus to which the present invention is applied.
The recording paper fed from the paper feeding unit 1 is adjusted in the lateral position by the lateral registration unit 2 and then passes through the leading edge registration sensor 3. At this timing, the process unit 4 is written with the image data by the optical writing unit 5, and starts image formation. The recording paper is electrostatically attracted and conveyed by the transfer belt 6, and when passing through each process unit 4, the transfer roller 7 transfers images one after another. Thereafter, the recording paper separated from the transfer belt 6 by the separation charger 8 fixes the image by the heat and pressure of the fixing unit 9, and advances to the transport unit 10. When the switching guide plate 11 selects the discharge tray 12 or the double-sided unit 13, and when the double-sided unit 13 is selected, the recording paper is switched back, and after stacking several sheets, the sheets are fed again.

FIG. 2 is a diagram for explaining the details of the present invention. A pair of skewed sponge rollers (lower driven skewed rollers) 15 are provided on the upstream side of the registration rollers 14. The oblique sponge roller 15 is rotatably connected to the arm 16 and further connected to the solenoid 17. When the solenoid 17 is turned on, the roller 15 is configured to be spaced apart upward with the arm 16 around the arm 18. The roller 15 is driven at substantially the same speed in the same direction as the registration roller 14 via a belt, a pulley and the like (not shown). A conveyance roller pair is provided in the R portion on the upstream side of the oblique sponge roller 15. The carrying roller 19 is rotatably engaged with the arm 20, and the lower roller is rotationally driven in the carrying direction by a pulley or the like not shown. The arm 20 is configured to be rotatable around a center 21, and a long hole 22 at the tip is engaged with a pin 23 of the oblique sponge roller arm 16. As a result, the skewed sponge roller arm 16 and the transport roller arm 20 are interlocked with each other, and when the solenoid 17 is OFF, the skewed sponge roller 15 is pressed by the pressing force of the spring 24 applied to the arm 16 as shown in FIG. Is pressed by the driven roller below, and the transport roller 19
Are separated. On the contrary, when the solenoid 17 is turned on, as shown in FIG.
Are separated. The operation of the present invention will be described below with reference to the drawings.

(Inventions 1 and 2) The sheets conveyed one by one from the sheet feeding unit 1 are bitten by the inlet roller 25 in FIG. 2 and further turned 90 degrees to the right at the turn portion 26. Then, it is sent to the horizontal transport unit 27. This time,
When the solenoid 17 is in the ON state, the oblique sponge roller 15
Are separated. After the trailing edge of the sheet has passed through the entrance roller 25 and before the leading edge is caught by the registration roller 14, the solenoid 17 is turned off and the oblique sponge roller 15 is pressed. At the same time, the conveying rollers 19 that are connected are separated upward. At this time, the paper 40 is a skewed sponge roller 1.
Since only the carrying force of 5 is given, as shown in FIG. 4, the carrying force in the oblique front direction (direction of arrow F) is easily given, and the front end portion extends to the position along the side fence 28 from 5 to 5.
Moved to the front side by 7 mm. This mechanism regulates the position of the front end of the sheet and keeps it at a fixed position for lateral registration.

The registration roller 14 is provided on the lower left side of the transfer belt 6 and has a higher pressing force than the other rollers. Therefore, the sheet tightly held by the registration rollers 14 is conveyed to the transfer belt 6 while maintaining the lateral registration position described above. The vertical resist is made by detecting the center of the leading edge of the paper with the fiber type photoelectric switch 29. Since the registration roller 14 rotates at a constant speed without stopping during conveyance, the sheet tightly held by the registration roller 14 is fed while maintaining a constant speed. Therefore, if the reading variation of the paper detection sensor 29 immediately before transfer is small, the writing position on the downstream side can be controlled with high accuracy.

(Invention of Claim 3) One end of the spring 24 is engaged with a pin 31 provided on the rotary plate 30. The rotary plate 30 is coaxially connected by a motor 32 and driven to rotate. Since the pin 31 is provided at a position deviated from the center of the rotary plate 30, the position thereof is changed by rotation, and thus the tension of the spring 24 is changed. As a result, the pressure applied to the oblique sponge roller 15 can be changed.

(Invention of Claim 4) The rotary plate 30 or the medium interlocked with the rotary plate 30 is provided with markings 33 such as slits. Further, detection sensors 34, 35 are provided at positions corresponding to the marking 33, and the sensor 34 causes the spring tension to become minimum (bottom dead center), the sensor 3
The highest point (top dead center) is detected by 5. An encoder or the like is provided inside the motor 32 or on a rotating body that is interlocked with the motor 32, and the rotation of the motor 32 is controlled by the generated pulses. When the paper is not conveyed, the rotary plate 30 is at the bottom dead center (the point where the sensor 34 detects the marking).
The oblique tension sponge roller 15 is applied with the initial tension A. When a parameter indicating the sheet thickness (for example, sheet weight g / m ² ) is input, the rotation plate 30 is rotationally controlled so as to apply a pressing force to the skewed sponge roller 15 corresponding thereto. Specifically, as shown in FIG. 5, by rotating the top-bottom dead center in a plurality of steps in accordance with the weight of the sheet, the pressing force of a plurality of steps, that is, the optimum pressing force according to the sheet thickness is given. be able to.

(Invention of Claim 5) A temperature / humidity detecting sensor is provided inside or near the conveying device. When the temperature or humidity exceeds the set temperature or set humidity by this sensor, the motor is rotated by a certain pulse in the direction in which the tension is weakened.

[0020]

According to the first aspect of the present invention, when the skew roller is moving the sheet, the transport force of the other transport roller that is eating the sheet is released. Therefore, when the sheet thickness is thin, If there is no conveyance resistance at the trailing edge and the trailing edge of the paper is moved closer, it is possible to prevent the occurrence of a jam in which the leading edge is buckled and the leading edge buckles. On the other hand, when the paper thickness is thick, a sufficient carrying force can be given by this carrying roller except when pressing the oblique sponge roller, and there is no decrease in the carrying speed due to the slip between the paper and the carrying roller, and during continuous paper passing. It is possible to prevent a jam that cannot be detected by the sensor because the distance between sheets disappears.

According to the second aspect of the present invention, since the above-mentioned release-pressurization is interlocked by the skewed sponge roller and the conveying roller, troublesome ON-OFF control of each roller can be easily and surely performed.

According to the third aspect of the present invention, since the pressing force of the skew roller is variable, a curved portion is provided in the conveying path, and the conveying resistance changes depending on the sheet thickness,
Optimal conveying force can be given.

According to the invention of claim 4, since the pressing force is set in accordance with the sheet thickness, it is possible to simply select the optimum information for any sheet without the troublesome setting of the pressing force by simply inputting the sheet thickness information. Conveyance power can be given.

According to the invention of claim 5, a temperature / humidity detecting mechanism is provided inside or in the vicinity of the conveying device, and when the high temperature and high humidity is detected, the pressing force of the skew roller is reduced.
It is possible to give an optimum carrying force without causing buckling jam.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an example of an image forming apparatus to which the present invention is applied.

FIG. 2 is a main part configuration diagram for explaining an operation at the time of pressurizing the skew roller.

FIG. 3 is a configuration diagram of a main part for explaining an operation when the skew roller is not pressurized.

FIG. 4 is a main part plan view for explaining the operation of the present invention.

FIG. 5 is a diagram for explaining an example of a method for adjusting the pressing force of the skew roller.

[Explanation of symbols]

14 ... Registration roller, 15 ... Oblique roller, 17 ... Solenoid, 19 ... Conveying roller, 24 ... Spring, 25 ... Entrance roller, 28 ... Side fence, 29 ... Paper position detection switch, 40 ... Paper.

Claims (5)

[Claims] 1. A conveying device of a type in which sheets are conveyed separately and conveyed one by one by a skew roller, the ends of the sheets are aligned along a reference plane, and the position of the sheet is regulated to a constant value. A paper transporting device that releases the transporting force of other transport rollers that are eating the paper when the sheet is being pulled. 2. The skew roller is configured to be capable of pressure-non-pressurization variation, and when the skew roller is under pressure, the conveyance roller that is eating another sheet is released, and the skew roller is skewed. The sheet conveying apparatus according to claim 1, wherein the conveying roller is configured to be pressurized when the roller is not pressurized. 3. A conveying device of a system in which sheets that are separately conveyed one by one are brought close to each other by a skew roller, and an end portion is along a reference surface to regulate the position of the sheet to a constant value. A sheet conveying device characterized in that the pressure is variable. 4. The sheet conveying apparatus according to claim 3, wherein the pressing force of the skew roller is switched in a plurality of steps by previously inputting the thickness of the sheet to be separated and conveyed. 5. The sheet conveying apparatus according to claim 3, wherein a temperature / humidity detecting mechanism is provided inside or near the conveying apparatus, and the pressing force of the skew roller is switched to a plurality of stages based on the detection result. .