JP2001187654A - Roller unit adjusting presser force and sheet material carrier mechanism in image formation device provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roller unit adjusting a presser force and a sheet material carrier mechanism in an image processing device provided therewith. SOLUTION: A holder 11 having a roller 12 attached via a clamp shaft 14 in such a state as movable in the loading direction from the circumference is provided with a torsion spring 13 connecting the clamp shaft 14 in the pressure reducing direction, and the winding degree of a coil 13a of the torsion spring 13 is adjusted by engagement between an engagement arm 13b projecting from the coil 13a and either of a first or a second stopper 11e, 11f provided in the holder side so that the presser force of the roller 12 can be adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller unit capable of adjusting a pressing force against a sheet material to be nipped, and a sheet material transport mechanism in an image processing apparatus using the same.

[0002]

2. Description of the Related Art Rollers are widely used in various equipment fields. For example, in a steel sheet rolling line or a large flat material conveying line, a large number of pairs of rollers are arranged above and below the line or on both sides of the line. Equipment for guide and roll forming is usually used. In addition to such large-sized equipment, various rollers are similarly used in the field of so-called office equipment for image formation and image reading such as copying machines, facsimile machines, and image scanners. In the case of office equipment, the roller to be nipped or guided is paper, and therefore, for example, a roller having a very simple and lightweight structure using resin is generally used.

As described above, the rollers are used in various fields. However, the setting of the nip force by the rollers is not limited to the rolling of the steel sheet and the conveyance of the sheet material and the paper feeding and the conveyance in the office equipment. Very important. This nip force is set by the distance between the shafts of the pair of rollers or the elastic urging force acting between the rollers. In a rolling facility or a large-size material transfer facility, a nip force or a rolling force is adjusted by a link mechanism including a hydraulic or pneumatic cylinder or a spring connected to a roller shaft. In equipment including such a cylinder and a link mechanism, the rigidity of the mechanism for setting the nip force and the rolling force is high, and the occupied space is large.

[0004]

On the other hand, also in the related field of office equipment, as described above, a configuration in which a sheet or other sheet material is guided using a pair of rollers or conveyed by frictional force is adopted. Have been. It is important to set the nip force between the rollers even in such a guide and conveyance by the roller pair. For example, in an image scanner or the like, the image reading becomes stable unless the nip force before and after the image reading unit is increased to some extent. Instead, it is preferable to set the nip force to a small value so that excessive tension is not applied to the sheet by simple guide or conveyance.

[0005] On the other hand, image scanners and other office equipment for reading or forming images have a very large number of parts and circuits incorporated in the limited space of the main body. For this reason, it is said that setting the nip force of the roller pair with a cylinder or a link mechanism is impractical from the viewpoint of an installation space. Therefore, in order to set the nip force, the positioning accuracy of each of the roller pairs is increased and the distance between the shafts is appropriately determined.

However, in the case where the nip force is adjusted only by the distance between the shafts of the roller pair, the intended purpose cannot be achieved unless the assembly accuracy of the roller pair is increased. That is,
It is very difficult to set the nip force with high precision because there is a manufacturing error of the roller itself and an error in assembling the supporting member for supporting the roller. In addition, since the support member that supports the rollers is fixedly arranged along the transport path of the paper or the like,
Once the position of the support member is determined, no adjustment such as changing the nip force of the roller pair can be made. Therefore, the nip force becomes too strong or too weak depending on the thickness and quality of the paper, and the function of transporting and guiding the paper is impaired.

As described above, the roller nip force of a guide roller of a large facility can be freely changed by using a cylinder or a link mechanism, but the nip force of a guide or a transfer roller of a small office equipment is reduced. There is a problem that it cannot be changed or adjusted, and has a considerable effect on image reading and image formation.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a roller unit capable of adjusting a pressing force and a sheet material conveying mechanism in an image processing apparatus having the same.

[0009]

According to the present invention, there is provided a roller unit capable of adjusting a pressing force, comprising: a roller; and a holding shaft having a length protruding from an axial end face of the roller and rotatably holding the roller. A torsion spring connected to the holding shaft in a direction of pressing down the holding shaft protruding from the end face of the roller, and torsion torque changing means for changing a torsion torque of the torsion spring. Features.

In such a configuration, the pressing force of the roller can be changed by changing the torsional torque of the torsion spring.

Further, if a roller unit arranged so as to form a nip portion with a transport driving roller is applied to an image processing apparatus for transporting a sheet material such as paper, the pressing force suitable for transporting the sheet material can be easily reduced. Can be set to

[0012]

According to the first aspect of the present invention, a roller, a holding shaft having a length protruding from an axial end face of the roller and rotatably holding the roller, and protruding from an end face of the roller are provided. A roller capable of adjusting a pressing force, comprising: a torsion spring connected to the holding shaft in a direction to lower the holding shaft; and torsion torque changing means for changing a torsional torque of the torsion spring. This is a unit and has an effect that the pressing force of the roller can be changed by changing the torsional torque of the torsion spring.

According to a second aspect of the present invention, there is provided a holder provided with a support shaft for rotatably mounting a holding shaft and for externally inserting a winding portion of a torsion spring, wherein the holder has a holding protruding from an end face of the roller. The shaft is provided with a long hole that can move in the torsion direction of the torsion spring, and the torque changing means is further provided with an engagement arm protruding from the winding part of the torsion spring, and a winding degree of the winding part formed on the holder. 2. The roller unit according to claim 1, further comprising a plurality of stoppers for locking the engaging arm corresponding to the position to be changed. By simply changing, the pressing force of the roller can be changed to the same number of steps as the number of stoppers.

According to a third aspect of the present invention, there is provided an image processing apparatus for reading an image from a sheet material such as paper or performing image formation on a sheet material based on input image information.
3. An image processing apparatus comprising: a roller unit according to claim 1 or 2 disposed in a transport path for transporting a sheet material; and a transport drive roller formed to form a nip with a roller of the roller unit and driven to rotate. This is a sheet material transport mechanism in the apparatus, and has an effect that stable sheet material transport can be performed by applying a pressing force suitable for sheet material transport to the sheet material.

According to a fourth aspect of the present invention, the roller unit in which the torsion spring has a high torsional torque is disposed immediately before and after the image reading unit or the image forming unit in the transport path. A sheet material transport mechanism in the image processing apparatus according to claim 3, which has an effect of improving the accuracy of image reading and image formation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 4 show details of a roller unit according to the present embodiment. FIG. 1 is a right side view of the roller unit according to the present invention, and FIG. 2 is a bottom view of the roller unit shown in FIG. FIG. 3 is a front view of the roller unit of FIG. 1, and FIG. 4 is a partially cutaway right side view of the roller unit when the urging force of the torsion spring is increased.

In FIG. 1 to FIG.
1 includes a holder 11 fixed to frames 50 of various devices by screws 11a, a roller 12 rotatably supported by the holder 11, and a torsion spring 13 for urging the roller 12 downward in FIG. It is included as an important member.

The holder 11 has a pair of brackets 1 facing downward.
1b. The bracket 11b is provided with a long hole 11c having a long axis in the vertical direction in a mounting portion of the roller 12, and a pair of support shafts 11d for supporting the torsion spring 13 on the inner wall near the screw 11a.

The roller 12 has a through hole 12a in its axial direction.
And assembled by inserting the holding shaft 14 into the through hole 12a. The holding shaft 14 has a circular cross section and rotatably holds the roller 12 therearound. Both ends of the holding shaft 14 are inserted into the elongated holes 11c of the bracket 11b and connected to the holder 11. Note that the roller 12 and the holding shaft 14 are
2 and 3, that is, an assembly structure in which both ends of the holding shaft 14 protrude from the both ends of the roller 12 by the same length from each other. Then, even if there is such a restriction, the roller 12 can be rotated easily around the holding shaft 14 passed through the through hole 12a.

As shown in FIG. 3, the holding shaft 14 has an engaging groove 14a formed in a part of the peripheral surface at both ends.
The torsion spring 13 can be engaged and held in these engagement grooves 14a. The engagement groove 14a is
In FIG. 3, the torsion spring 13 has a concave cross section as shown in an enlarged notch diagram encircled by a circle A, and as shown in an enlarged cross sectional view in a circle B shown as a cross section taken along line aa of the enlarged notched diagram. It is formed so as to cover from above.

As shown in FIG. 1, the torsion spring 13 has a pair of winding portions 13a extrapolated around a support shaft 11d.
And an engagement arm 13 between these winding portions 13a.
b, and a biasing arm 13c extending from the winding portion 13a in the direction of the roller 12.
The urging arm 13c enters the engaging groove 14a of the holding shaft 14 as shown in FIG. 3 and elastically urges the holding shaft 14 downward. At this time, the urging arm 13c is in a circle B in FIG.
As shown in the enlarged view surrounded by, the flat pressing surface 14b of the engagement groove 14a is pressed, so that the rotation of the holding shaft 14 is restricted. In addition, the holding shaft 14 has a long hole 11c of the bracket 11b.
When a load is applied upward from the lower side, it is pushed upward against the urging force of the urging arm 13c, and the restoring reaction force of the urging arm 13c at this time is Will act as a pressing force.

The pressing force of the roller 12 is substantially proportional to the torsional torque of the torsion spring 13, and the pressing force of the roller 12 can be adjusted by changing the torsional torque. Therefore, in the present invention, the torsion torque is switched in two stages by changing the degree of bending of the engagement arm 13b of the torsion spring 13, so that the first stopper is provided on the lower surface of the holder 11 as shown in FIGS. 11e and a second stopper 11f are provided. These first and second stoppers 11e and 11f are projections arranged at an interval parallel to each other. In FIG. 1, the engagement arm 13b of the torsion spring 13 is locked by the first stopper 11e. I have.

In the above configuration, the holder 11 fixed to the frame 50, which is a fixing point, with the screw 11a is also held in the posture shown in FIG. When the roller 12 is pressed against the surface of a sheet material or the like, the restoring force of the torsion spring 13 corresponding to the pressing force acts as a pressing force on the sheet material. At this time, the urging arm 13c of the torsion spring 13 is
4a, and has a degree of freedom to move left and right in the engagement groove 14a as shown in an enlarged view surrounded by a circle A in FIG.
For this reason, when the sheet material is not parallel to the axis of the holding shaft 14 in FIG. 3 and has, for example, a flat surface that rises to the right, the roller 12 is tilted obliquely upward as indicated by a dashed line in the drawing. Displacement movement is possible. That is, the roller 12 can change the posture and press the sheet material not only in the vertical direction but also in the oblique posture with a certain degree of freedom in the direction orthogonal to the axis.

Here, the torsional torque of the torsion spring 13 varies depending on the degree of winding of the winding portion 13a. That is, instead of locking the engagement arm 13b with the first stopper 11e as shown in FIG. 1, instead of locking the engagement arm 13b with the second stopper 11f as shown in FIG. The winding degree of the winding part 13a increases. Therefore, the torsion spring 13 also has a large torsional torque, and the urging arm 13c has a strong force to push down the holding shaft 14. Therefore, the pressing force of the roller 12 against the sheet material or the like also increases.

As described above, the engagement arm 13 of the torsion spring 13 for urging the holding shaft 14 in the downward direction is used.
Depending on which of the first and second stoppers 11e and 11f is engaged with b, the pressing force of the roller 12 against the sheet material can be changed. Therefore, when the roller unit 10 is incorporated in a sheet conveyance path of a copying machine or another image processing apparatus, it is possible to feed a sheet with a different pressing force.

FIG. 5 is a schematic perspective view of an image scanner provided with a sheet material supply mechanism according to the present invention. In this embodiment, an image scanner for reading an image from a document and electronically filing the image will be described as an example.

As shown in the figure, the image scanner comprises a main body 1 having a built-in optical system reading section and a paper conveyance path, and an automatic paper feeding device 2 as paper feeding means. The main body 1 has an operation panel 1a on the front and a controller (not shown) for controlling all devices inside. On the upper surface of the main body 1, there is provided a collection tray 1b for receiving the paper fed from the automatic paper feeder 2 and having finished the image reading by the reading unit.

The automatic paper feeder 2 has a main body 1 on which paper is mounted.
FIG. 6 is a schematic view of the automatic paper feeder from the hopper to the paper transport path and the collection tray.

The automatic paper feeder 2 includes a housing 2a and a hopper 2b incorporated therein so as to be rotatable up and down.
b is driven by being connected to a motor (not shown), and when feeding the paper, the paper P is rotationally urged upward until the paper P comes into contact with the supply roller 3a as shown in FIG. Further, on the upper surface of the hopper 2b, there is provided a guide for guiding the sheet P in the width direction.
It has a pair of guides 2d that can be manually moved in the frontage direction (left-right direction when viewed from the front).

A pair of a separation roller 3b and a retard roller 3c for preventing double feeding of the paper P is disposed downstream of the supply roller 3a that picks up and feeds the paper P one by one on the hopper 2b. Collection tray 1 from roller pair
A conveyance path for the sheet P is formed between the sheet P and the sheet B. A first scanning sensor 3d for reading the original image on the upper surface of the paper P and a second scanning sensor 3e for reading the original image on the lower surface of the paper P are arranged in the transport path of the paper P. The transport path for transporting the paper P picked up from the hopper 2b by the supply roller 3a is provided with a seven-stage transport drive roller 4 and a roller unit 10 paired therewith. In FIG. 6, the reference numerals assigned to the roller unit 10 indicate that the torsion springs 13 have the same set value of the torsional torque as 10-1 and 10-2, respectively.

Each of the transport drive rollers 4 is synchronously rotated by a common drive motor (not shown).
The peripheral surface is brought into contact with the peripheral surface of the roller 12 of each of the roller units 10-1 and 10-2. Roller unit 10-
Reference numeral 1 denotes an engagement arm 13b of the torsion spring 13 which is engaged with the first stopper 11e as shown in FIG. 1, and the nip force with respect to the paper P between the transport drive roller 4 and the transport drive roller 4 is relatively low. Is set. On the other hand, immediately before the first scanning sensor 3d and the roller unit 10-2 of the second scanning sensor 3e, the engaging arm 13b shown in FIG. 4 is engaged with the second stopper 11f. Therefore, the nip force to the sheet P is strong before and after the first and second scanning sensors 3d and 3e, and is smaller than this in other cases.

In the image scanner having the above configuration, when the operation button 1a-1 on the operation panel 1a is turned on, the supply roller 3a starts rotating in the direction of the arrow in FIG. 6 to pick up one sheet P on the hopper 2b. Separation roller 3
b and the retard roller 3c. Then, when the leading end of the paper P is nipped between the first-stage transport drive roller 4 and the roller 12 of the roller unit 10-1 (see FIGS. 1 to 4), the paper P becomes rimless with the supply roller 3a side, The transport drive roller 4 and the roller unit 1 up to the seventh stage
A constant speed feed is given by 0-1 and 10-2.

When the paper P from the hopper 2b enters the first-stage transport drive roller 4 and the roller unit 10-1,
Since the nip force is set to be loose, the leading edge of the paper P is easily nipped, and the paper jam does not occur. Also, the fourth
The transport drive roller 4 and the roller unit 1 from the first stage to the last stage
0-1 passes the sheet P in an arc shape, but since the nip force of these roller pairs is also set to be low, the sheet P
As a result, the paper jam is suppressed. On the other hand, since the nip force between the transport drive roller 4 and the roller unit 10-2 immediately before and immediately after the first and second scanning sensors 3d and 3e is set to be strong, the paper P is moved between these two stages. Slippage during conveyance by the roller pair is prevented. Therefore, the first and second scanning sensors 3d, 3
The image reading by e can be executed with high accuracy, and the image can be read without causing the flow or omission of the image.

As described above, since the urging force of the torsion spring 13 of the roller unit 10 can be switched and used in two stages, if the paper P is incorporated in a portion where the paper P is easily jammed, the urging force is reduced, and image reading and image formation are performed. In the position (2), high-precision image processing becomes possible by increasing the urging force.

In the embodiment, the urging force of the torsion spring 13 is switched in two stages by the first and second stoppers 11e and 11f. However, the number of setting stages of the urging force is increased by increasing the number of stoppers. Can be increased.
If an eccentric cam that rotates by manual operation is provided on the holder 11 and the engaging arm 13b is brought into contact with the peripheral surface of the eccentric cam, the biasing force can be continuously adjusted in multiple stages.

[0037]

According to the roller unit of the present invention, the pressing force of the roller can be freely changed according to the change of the torsional torque of the torsion spring. The roller pressing force suitable for the processing can be set and used, and the versatility is improved.

Further, in the image processing apparatus having such a roller unit in the transport path, it is possible to stably feed a sheet material such as paper, and in particular, immediately before and immediately after the scanning for image reading or the printing section for image formation. By arranging a roller unit having a high torsional torque, more stable image reading scanning and image printing can be performed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway right side view of a roller unit according to the present invention.

FIG. 2 is a bottom view of the roller unit of FIG. 1;

FIG. 3 is a front view of the roller unit of FIG. 1;

FIG. 4 is a partially cutaway right side view of the roller unit when the urging force of the torsion spring is increased.

FIG. 5 is a schematic perspective view of an image scanner provided with a sheet material supply mechanism of the present invention.

FIG. 6 is a schematic diagram from the hopper of the automatic paper feeder to the paper conveyance path and the collection tray.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 1a Operation panel 1a-1 Operation button 1b Collection tray 2 Automatic paper feeder 2a Housing 2b Hopper 2d Guide 3a Supply roller 3b Separation roller 3c Retard roller 3d 1st scan sensor 3e 2nd scan sensor 4 Transport drive roller 10 , 10-1, 10-2 Roller unit 11 Holder 11a Screw 11b Bracket 11c Long hole 11d Support shaft 11e First stopper 11f Second stopper 12 Roller 12a Through hole 13 Torsion spring 13a Winding portion 13b With engaging arm 13c Force arm 14 holding shaft 14a engagement groove 14b pressing surface 50 frame P paper

Claims (4)

[Claims] A roller having a length protruding from an axial end face of the roller and rotatably holding the roller; and a holding shaft protruding from the end face of the roller being pressed down. A roller unit capable of adjusting a pressing force, comprising: a torsion spring connected to a holding shaft; and torsion torque changing means for changing a torsion torque of the torsion spring. And a holder provided with a support shaft for rotatably mounting the holding shaft and extrapolating a winding portion of the torsion spring, wherein the holder has a holding shaft protruding from an end face of the roller. The torsion spring is provided with an elongated hole movable in the torsion direction, and the torque changing means is further provided with an engagement arm protruding from a winding portion of the torsion spring, and a winding of the winding portion formed on the holder. 2. The roller unit according to claim 1, wherein said roller unit comprises a plurality of stoppers for locking said engaging arm in accordance with the position at which the degree is changed. 3. An image processing apparatus for reading an image from a sheet material such as paper or performing image formation on said sheet material based on input image information, wherein said image processing apparatus includes a conveying path for conveying said sheet material. A sheet material transport mechanism in an image processing apparatus, comprising a roller unit described above, and a transport drive roller that forms a nip with the roller of the roller unit and is driven to rotate. 4. The image forming apparatus according to claim 3, wherein the roller unit in which the torsion torque of the torsion spring is increased is disposed immediately before and immediately after an image reading unit or an image forming unit on the conveyance path. A sheet material transport mechanism in the image processing apparatus.