JPH09286539A - Sheet carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a driven gear to smoothly mesh with a drive gear when a pinch roller having the driven gear on its end part is brought in contact with a drive roller having drive gear on its end part. SOLUTION: A pinch roller 6 is allowed to come in/out of a drive roller 5 by means of the reciprocating action of a movable body 19 having a pressing surface 22 for pressing the shaft 8 of the pinch roller 6. Rotation transmitting parts 24, 25 composed of rugged surfaces and/or frictional members are formed on the pressing surface 22 and the shaft 8, and the shaft 8 is rotated together with a driven gear 18 by changing the contact point of the pressing surface 22 in contact with the shaft 8 during the process of the reciprocating action of the movable body 19. Therefore, even though the tooth tips of the drive gear 17 of the drive roller 5 and the driven gear 18 make contact with each other in the process of making the separated pinch roller 6 approach to the drive roller 5, the driven gear 18 is displaced in the rotational direction so as to release such a state as contact between the tooth tips of gears 17 and 18. Thereby, gears 17, 18 can mesh with each other smoothly.

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 used for office equipment.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a driving gear 103 is driven by a motor by pressing a pinch roller 102 against a driving roller 101 rotating at a fixed position by an urging member.
Is fixed to the end of the shaft of the drive roller 101, the driven gear 104 meshing with the drive gear 103 is fixed to the end of the shaft of the pinch roller 102, and the rotation of the motor is transmitted to the drive gear 103 and the driven gear 104. Drive roller 101 and pinch roller 102 are rotated, and the sheet is conveyed by the frictional force of rotating drive roller 101 and pinch roller 102.
There is a so-called friction transfer type sheet transfer device. In this case, the pinch roller 102 is supported at its both ends by guide holes 105 formed in a frame (not shown) so as to be vertically movable, and can be brought into contact with and separated from the drive roller. In addition, there is a sheet conveying device that is provided with a tractor separately and selects friction conveyance or tractor conveyance.

In such a sheet conveying device, the pinch roller 102 is separated from the driving roller 101 when the sheet is set or the sheet is conveyed by the tractor. In this case, even if the pinch roller 102 is separated from the drive roller 101, if the tooth tips of the drive gear 103 and the driven gear 104 interfere with each other, the pinch roller 102 rotates while floating from the drive roller 101. Therefore, when the module of the gears 103 and 104 is 1.5, the separation distance of the pinch roller needs to be 1.5 mm or more. When the separation distance is 1.5 mm, the gears 103, 104
The module is usually set to about 1 with a margin in mind.

[0004]

The pinch roller 102 separated from the drive roller 101 is replaced with the drive roller 10 again.
When the driving gear 103 and the driven gear 10 are pressed against each other,
4 may contact the tooth tips with each other, and both gears 103,
It is difficult to engage 104. Further, the pinch roller 102 has its both ends supported by supporting members such as roller arms and is separated from the drive roller 101. In this separated state, the pinch roller 102 itself is not restrained, and therefore the pinch roller 102 itself. The subtle bending of the shaft may cause vibration in the rotation direction, which may cause unpleasant noise.

[0005]

According to the first aspect of the present invention,
A drive roller that has a drive gear that is driven by a motor at its end and that rotates at a fixed position, and a driven gear that engages with the drive gear at the end that can be moved in and out of contact with and away from the drive roller. A pinch roller supported, wherein the pinch roller is pressed against the drive roller by an urging means to convey a sheet by the drive roller and the pinch roller. A movable body supported so as to reciprocate in a direction intersecting a virtual straight line connecting the center of the pinch roller and the axis is provided, and the axis of the pinch roller is moved in the process of moving the movable body in one direction. The contact point of contact with the drive roller is sequentially changed to form a pressing surface for pressing the shaft in a direction to separate the shaft from the driving roller, and the moving motion of the movable body is converted into a rotational force to convert the pinch into the pinch. The rotation transmitting means for transmitting to the shaft of over la formed on the outer periphery of the shaft of the pinch roller and the pressing surface.

Therefore, when the movable body is moved in one direction, the shaft of the pinch roller is pressed against the pressing surface, and the pinch roller moves away from the driving roller while moving relatively on the pressing surface. In the state where the pinch roller is separated from the drive roller and the movable body is stopped until the meshing state of the drive gear and the driven gear is released, the shaft of the pinch roller is supported by the pressing surface while being stopped by the rotation transmitting portion. .

When the movable body is moved in the other direction, the pressing surface retracts from the shaft of the pinch roller, so that the pinch roller approaches the drive roller. Even if the tooth tips of the drive gear and the driven gear come into contact with each other at the time of this approach, the shaft of the pinch roller relatively moves on the pressing surface, and the rotation transmitting portion is provided between the pressing surface and the outer circumference of the pinch roller shaft. Since it is formed, the pinch roller is displaced in the rotation direction together with the driven gear. This displacement in the rotation direction releases the state in which the tooth tips of the drive gear and the driven gear are in contact with each other.

The rotation transmitting portion of the invention according to claim 2 is formed by an uneven surface, and the rotation transmitting portion of the invention according to claim 3 is formed by a friction member. Therefore, the rotational movement of the pinch roller shaft when the pinch roller shaft relatively moves on the pressing surface of the moving movable body is promoted.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. First, FIGS. 3 and 4 show an outline of the dot printer. 1 is a platen. The dot printer head 2 arranged opposite to the front surface of the platen 1 is mounted on a carrier (not shown) that is reciprocally driven along the longitudinal direction of the platen 1 (the direction perpendicular to the paper surface). A sheet conveying path 4 for guiding the sheet 3 is provided between the platen 1 and the dot printer head 2, and two sets of a driving roller 5 and a pinch roller 6 facing each other with the sheet conveying path 4 in between are provided. There is. The shaft 7 of the drive roller 5 is rotatably supported at a fixed position by opposite side plates (not shown), while the shaft 8 of the pinch roller 6 is a guide hole (oblong hole) formed in the opposite side plates. A shaft 9 is vertically rotatably and rotatably supported by the drive roller 5 so as to move in and out of the drive roller 5. Further, a tractor 10 is provided on the extension surface of the sheet conveying path 4, and the conveying direction of the sheet 3 is changed between the tractor 10 and the nearest drive roller 5 by rotating about a support shaft 11. A switching lever 12 for switching is provided.

As shown in FIG. 1, the shaft 8 protruding from both ends of the pinch roller 6 is biased downward by a torsion coil spring 13 as a biasing means. The urging means here includes urging the pinch roller 6 toward the drive roller 5 side by its own weight. The torsion coil spring 13 is a leg 1 supported by a stopper 14.
5 and a leg 16 for pressing the shaft 8 of the pinch roller 6.

A drive gear 17 driven by a motor (not shown) capable of rotating in the normal and reverse directions is fixedly fitted to the shaft 7 protruding from one end of the drive roller 5, and one end of the pinch roller 6 is connected. A driven gear 18 that meshes with a drive gear 17 is fixedly fitted to the shaft 8 protruding from the shaft 8.

A movable body 19 is reciprocally movable in a direction intersecting at right angles with an imaginary straight line connecting the centers of the shafts 7 and 8 of the drive roller 5 and the pinch roller 6. The movable body 19 is, for example, the shaft 7 of the drive roller 5.
It is slidably supported in a linear direction by a side plate or the like that pivotally supports, and is moved manually or by a drive source such as a solenoid. On its upper surface, a smooth surface 20 parallel to the moving direction of the movable body 19, Step 2 rising from the end of the smooth surface 21
1 and the pinch roller 6 as it separates from the step 21
The pressing surface 22 that presses the shaft 8 while inclining in the direction toward the side
And an extending surface 23 extending horizontally from the end of the pressing surface 22.

On the surfaces of the pressing surface 22 and the extending surface 23, a rotation transmitting portion 24 having an uneven surface is formed. Further, a rotation transmitting portion 25 having an uneven surface is formed on the outer circumference of the shaft 8 of the pinch roller 6. These rotation transmission parts 24, 25
The concavo-convex surface for forming the ridge includes parallel knurls, oblique knurls, teeth such as gears and racks, and the like. In addition, the pressing surface 22, the extension surface 23, the pinch roller 6
By attaching a sheet-shaped friction member such as rubber, urethane, or cork to the outer peripheral surface of the shaft 8 of the rotation transmitting portions 24, 2
5 may be formed.

In such a structure, when the sheet 3 to be printed is passed through the sheet conveying path 4, the pinch roller 6 is separated from the drive roller 5. In the present embodiment, as shown in FIG. 3, when the sheet 3 is conveyed without using the tractor 10 for printing, two sets of pinch rollers 6 are brought into pressure contact with the drive roller 5 and the support shaft 11 is used as a center. Switching lever 1
Seat 3 inserted from the left in the figure by rotating 2 upward
Is conveyed rightward by the two sets of the drive roller 5 and the pinch roller 6 and is discharged upward by the switching lever 12 from the direction toward the tractor 10.

When the sheet 3 is continuous paper, the tractor 10
When the sheet 3 is conveyed by using the paper, the pinch roller 6 between the tractor 10 and the dot printer head 2 is separated from the drive roller 5 as shown in FIG. Press it against 5. In this case, the tractor 10 feeds the sheet 3, and the printed sheet 3 is pulled out by the left driving roller 5 and the pinch roller 6.

When driving the pinch roller 6, as shown in FIG.
As shown in (a), the movable body 19 is moved to the right and maintained in a state in which the smooth surface 20 faces the shaft 8 of the pinch roller 6. There is some clearance between the shaft 8 of the pinch roller 6 and the smooth surface 20, and the pinch roller 6 is pressed against the drive roller 5 by the urging force of the torsion coil spring 13. Therefore, the drive gear 17 and the driven gear 18 are maintained in the meshed state, and the drive roller 5 and the pinch roller 6 rotate by driving the motor.

When the tractor 10 is used, or when the pinch roller 6 is moved away from the drive roller 5 in order to pass the sheet 3 through the sheet conveying path 4, the movable body 19 is moved to the right as shown in FIG. 1 (b). From left to left. By this movement, the shaft 8 of the pinch roller 6 is pressed by the pressing surface 22, so that the pinch roller 6 is separated from the drive roller 5 against the biasing force of the torsion coil spring 13.

In this case, as shown in FIG. 4, when the sheet 3 is conveyed by the left driving roller 5 and the pinch roller 6, the driving force is also transmitted to the driving roller 5 on the tractor 10 side. The shaft 8 of the pinch roller 6 facing the drive roller 5 on the side of the tractor 10 is supported by the pressing surface 22 or the extension surface 23 in a stationary state, and is prevented from rotating by the rotation transmitting portion 24. Therefore, the pinch roller 6 does not vibrate in the rotation direction even when the driving roller 5 is vibrated, which contributes to the reduction of noise.

When the movable body 19 is moved to the right from the state shown in FIG. 1A, the pinch roller 6 is lowered by the urging force of the torsion coil spring 13 and is brought into pressure contact with the drive roller 5. In this way, the pinch roller 6 comes in contact with and separates from the drive roller 5 by the reciprocating motion of the movable body 19, but the shaft 8 of the pinch roller 6 is supported by the vertically long guide hole 9 (see FIGS. 3 and 4). Since it is moved in the vertical direction, the contact point on the pressing surface 22 with which the lower outer periphery of the shaft 8 contacts changes. That is, the shaft 8 relatively moves along the pressing surface 22, and the rotation transmitting portions 24 and 25 that increase the frictional force are formed between the pressing surface 22 and the outer periphery of the shaft 8, so that the shaft 8 is driven by the shaft 8. It is displaced in the rotational direction together with the gear 18.

Therefore, even if the tooth tips of the drive gear 17 and the driven gear 18 come into contact with each other in the process of bringing the pinch roller 6 in the separated state closer to the drive roller 5, the contact state is the rotational direction of the driven gear 18. It is released by the displacement of. Thereby, the drive gear 17 and the driven gear 18 can be smoothly meshed.

In the process in which the shaft 8 is raised and the driven gear 18 is disengaged from the drive gear 17, the shaft 8 pushes the pressing surface 22.
Even if a rotational force is received from the shaft 8, the shaft 8 floats from the pressing surface 22, so that an unreasonable force does not act on the meshing portion of the gears 17 and 18.

Although the movable body 19 is moved in the linear direction in the previous embodiment, a rotating movable body may be used. In this case, the locus of the free end of the movable body is supported so as to intersect a virtual straight line connecting the centers of the shafts 7 and 8 of the drive roller 5 and the pinch roller 6. Even in this case, the contact point between the movable body and the shaft 8 changes in the course of the rotational movement of the movable body, so that the movable body presses the shaft 8 (pressing surface) and the outer peripheral surface of the shaft 8. By forming the rotation transmission portion on the shaft 8, the shaft 8 can be displaced in the rotation direction together with the driven gear 18 in the process of bringing the pinch roller 6 into and out of contact with the drive roller 5.

[0023]

According to the first aspect of the present invention, a drive roller having a drive gear at its end portion and a driven gear meshed with the drive gear at its end portion are supported so as to be able to come into contact with and separate from the drive roller. The movable pinch roller is pressed against the pinch roller by an urging means, and is provided with a movable body supported so as to reciprocate in a direction intersecting a virtual straight line connecting the centers of the axes of the drive roller and the pinch roller. In the process of moving the movable body in one direction, the contact point for contacting the shaft of the pinch roller is sequentially changed to form a pressing surface for pressing the shaft in the direction of separating from the drive roller. Since the rotation transmitting portion for converting the moving motion into the rotational force and transmitting the rotational force to the shaft of the pinch roller is formed on the pressing surface and the outer periphery of the shaft of the pinch roller, the pinch can be achieved by moving the movable body in one direction. Laura's Can be separated from the pinch roller is pressed by the pressing surface from the drive roller. Further, by moving the movable body in the other direction, the pinch roller can be pressed against the drive roller by the urging means. In this case, the shaft of the pinch roller relatively moves on the pressing surface, and since the rotation transmitting portion is formed between the pressing surface and the outer circumference of the shaft, the tips of the drive gear and the driven gear come into contact with each other. Even in this case, the shaft of the pinch roller is displaced in the rotational direction together with the driven gear to release the state where the tooth tips of the drive gear and the driven gear are in contact with each other, and the drive gear and the driven gear can be smoothly meshed. Furthermore, when the shaft of the pinch roller is separated from the drive roller and the movable body is stopped, the rotation transmission unit stops the shaft of the pinch roller from rotating, thus suppressing vibration in the rotation direction of the pinch roller and reducing noise. Can contribute.

Since the rotation transmitting portion of the invention according to claim 2 is formed by an uneven surface and the rotation transmitting portion of the invention according to claim 3 is formed by a friction member, it is formed on the pressing surface of the moving movable body. Thus, the rotational movement of the pinch roller shaft when the pinch roller shaft relatively moves can be promoted.

[Brief description of drawings]

FIG. 1 is a side view showing a state in which a pinch roller is brought into contact with and separated from a drive roller by a movable body according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a relationship between a pinch roller shaft and a movable body.

FIG. 3 is a side view schematically showing the dot printer in a state where a sheet is conveyed by a driving roller and a pinch roller.

FIG. 4 is a side view showing an outline of the dot printer in a state where a sheet is conveyed using a tractor.

FIG. 5 is a side view showing a contact / separation operation of a pinch roller with respect to a drive roller in a conventional example.

[Explanation of symbols]

 3 sheet 5 drive roller 6 pinch roller 7, 8 shaft 13 biasing off 17 drive gear 18 driven gear 19 movable body 22 pressing surface 24, 25 rotation transmitting section

Claims (3)

[Claims] 1. A drive roller which has a drive gear driven by a motor at its end portion and rotates at a fixed position, and a driven gear which meshes with the drive gear at its end portion and is brought into contact with or separated from the drive roller. A pinch roller supported rotatably and rotatably, the pinch roller is pressed against the drive roller by an urging means, and the sheet is conveyed by the drive roller and the pinch roller. In the process of moving the movable body in one direction, the movable body is provided so as to be reciprocally movable in a direction intersecting with a virtual straight line connecting the centers of the drive roller and the pinch roller. The contact point that contacts the shaft of the pinch roller is sequentially changed to form a pressing surface that presses the shaft in a direction of separating it from the drive roller, and the movement of the movable body is converted into a rotational force. Sheet conveying apparatus characterized by a rotation transmitting portion which transmits to the shaft of the pinch roller is formed in the outer periphery of the shaft of the pinch roller and the pressing surface Te. 2. The sheet conveying device according to claim 1, wherein the rotation transmitting portion is formed by an uneven surface. 3. The sheet conveying device according to claim 1, wherein the rotation transmitting portion is formed of a friction member.