JP2000338813A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fixing device which does not generate meandering and wrinkle of paper and can realize fixing of high quality. SOLUTION: The fixing device is provided with a cam-follower 16a installed at a part of an arm member, a cam 21 installed by being in contact with the cam follower and a rotatable shaft member 28 supporting the cam 21. In this fixing device, a through hole 21a into which the shaft member 28 is inserted, a groove which is formed by projecting in a radial direction of the through hole 21a at a part of the through hole 21a and a hole which is formed at a flank of the cam in order to position to a positioning member used as a jig at the time of mounting the cam on the shaft member, are provided at the cam 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device having a pair of fixing rollers pressed against each other.
In particular, the present invention relates to a fixing device provided with a mechanism for adjusting a pressing force of a fixing roller in an axial direction.

[0002]

2. Description of the Related Art In a fixing device having a pair of fixing rollers, there is known a fixing device in which the pressing force in the axial direction of the fixing roller is adjusted to correct the meandering of the sheet generated during printing.

A paper meandering correction mechanism used in this type of fixing device is provided with cam mechanisms at both ends in the axial direction of a pressure roller, for example, and controls the cam mechanism to reduce the pressing force of the pressure roller against the heating roller. Generally, it is configured to adjust.

[0004]

However, since errors tend to occur in the mounting position of the cam and the pressing force of the fixing roller differs in the axial direction, meandering of the paper cannot be corrected or wrinkles occur on the paper. Was inviting.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device capable of realizing high quality fixing without generating meandering or wrinkles.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a bearing having bearings for holding bearings provided at both ends of a pressure roller,
An arm member rotatably provided with respect to a frame around an axis provided in parallel with the rotation axis of the pressure roller,
In a fixing device including a cam follower provided on a part of the arm member, a cam provided in contact with the cam follower, and a rotatable shaft member supporting the cam, the cam includes a shaft member. And a groove formed in a part of the through hole so as to protrude in a radial direction of the through hole, and a position of an alignment member used as a jig when the cam is mounted on the shaft member. This is achieved by providing a hole formed on the side surface of the cam for alignment.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. First, a case where the fixing device of the present invention is mounted on a continuous paper printing apparatus will be described with reference to FIG. In FIG. 1, a photosensitive drum 1 is supported so as to be rotatable in an arrow direction. As the photosensitive drum 1 rotates, the surface of the photosensitive drum 1 is uniformly charged to a predetermined potential by the charger 2, and an electrostatic latent image is formed on the photosensitive drum 1 by receiving a subsequent irradiation beam from the exposure device 3. Toner is supplied to the electrostatic latent image that has reached the developing area of the developing device 4, and the electrostatic latent image is visualized as a toner image. The toner image formed on the surface of the photosensitive drum 1 is electrostatically attracted to the paper 6 in a transfer area by the transfer device 5 and is transferred to the paper 6.

The paper 6 is a so-called continuous paper that is continuous in a long shape, and has feed holes (not shown) formed at predetermined intervals along the paper transport direction at both edges in the width direction. The paper 6 is transported by a transport puller 7, a paper transport tractor 8, and a fixing device 1.
0 and discharge puller 11. The feed holes provided in the paper 6 are mainly used for transport by the paper transport tractor 8.

In FIG. 1, reference numeral 13 denotes a sensor arranged at one end of the sheet 6 in the sheet width direction, which monitors the position of the edge of the sheet passing therethrough and detects a meandering state. In FIG. 1, reference numeral 9 denotes a buffer for absorbing slack or tension generated in the sheet 6 due to a difference in sheet conveying speed between the sheet conveying tractor 8 and the fixing device 10.

The toner image transferred on the sheet 6 in the transfer area is conveyed while being heated and pressed between the heating roller 10a and the pressure roller 10b constituting the fixing device 10, and is fixed on the sheet 6. Is done. The pressure roller 10b is in pressure contact with the heating roller 10a as indicated by a solid line during a printing operation, and the heating roller 1b as indicated by a dashed line when stopped.
It is configured to be released from the pressure contact state with Oa.

The paper 6 sent from the fixing device 10 is discharged to a stacker 12 via a discharge puller 11. on the other hand,
Toner remaining on the surface of the photosensitive drum 1 without being transferred to the sheet 6 in the transfer area is removed from the surface of the photosensitive drum 1 by the cleaner 14. The printing operation is continued by repeating the above operation.

Next, the configuration of the fixing device will be described in detail with reference to FIGS. The fixing device 10 includes a heating roller 10
a and a pressure roller 10b. Heating roller 10a
As shown in FIG. 3, bearings 101a are provided at both ends in the axial direction so as to travel from the end face of the heating roller 10a. A bearing 101a of the heating roller is fitted to a bearing holding portion 22a provided on the fixing base 22. As a result, the heating roller 10 a is rotatably supported by the fixing base 22.

As shown in FIG. 3, bearings 101b are provided at both ends in the axial direction of the pressure roller 10b so as to protrude from the end face of the pressure roller 10b. On the other hand, on the frame 23, bearings 101 provided at both ends of the pressure roller are provided.
An arm 15 having a bearing holding portion 15a for holding b is provided. The arm 15 is provided rotatably with respect to the frame 23 around a shaft 25 provided in parallel with the rotation axis of each roller. Similarly to the arm 15, the frame 23 is provided with an arm 16 that is rotatable around the shaft 25 with respect to the frame 23. At the free ends of the arms 15 and 16, a coil spring 20 sandwiched between a spring holder 19 provided on the arm 15 and the arm 16, and an elastic force of the coil spring 20 attached to the spring holder 19 are adjusted. A pressure adjusting screw 17 and a lock nut 18 are provided.

The frame 23 is provided with a cam 21 which is in contact with a cam follower 16a provided on a part of the arm 16, and the cam 21 is rotated by a motor 24 so that the arm 16 is rotated. The arm 15 is rotated via the
Pressing / separating from a.

An encoder 26 for indicating the position of the cam 21 is provided at one end of the shaft 28, and a sensor 27 for detecting the encoder 26 is provided for the frame 23.

Here, as shown in FIG. 4, the cam 21 is provided with a groove 21b which protrudes in a radial direction of the through hole at a part of the through hole 21a through which the shaft 28 is passed. A hole 21c is formed in a side surface of the hole 21. In addition, an alignment member 29 as shown in FIG. 5 is prepared in advance as a jig used when attaching the cam 21 to the shaft 28. The positioning member 29 is a cam follower 1
6a, a recess 29b engageable on the outer periphery of the shaft 28, and a hole 2 provided in the cam 21.
1c is provided with a protrusion 29c which can be freely engaged.

In the above configuration, the cam 21 is connected to the shaft 2
8, the positioning member 29 is connected to the cam follower 1 via the concave portions 29a and 29b of the positioning member 29.
6a and the shaft 28 and the cam 21
Is rotated, and the cam 21 is fixed to the shaft 28 in a state where the hole 21c of the cam 21 and the projection 29c of the positioning member 29 are aligned. Then, in a state where the cam 21 is fixed to the shaft 28, the pressure roller 10 b
When the pressure applied to the device fluctuates for each device or when imbalance occurs between left and right values, the pressure is adjusted by turning the pressure adjusting screw 17. At this position, the mounting position of the sensor 27 is adjusted so as to detect the slit of the encoder 26, and stored in a storage device (not shown) as the reference position of the cam 21.

At the start of printing, the cam 21 rotates to a position where the groove 21b faces the cam follower 16a, and the pressure applied from the arm 16 is applied to the heating roller 10a via the pressure roller 10b, 10
The pressing force between b and the heating roller 10a becomes uniform in the axial direction.

During printing, a sensor 13 provided in the printing apparatus is used.
Cam 2 based on the result of the paper running position detected by
1 is rotated by the motor 24 to control the pressure balance in the axial direction of the pressure roller 10b to correct the meandering of the sheet while changing the running position of the sheet running on the fixing device 10.

[0020]

As described above, according to the present invention, the running position of the paper can be controlled stably, so that the meandering and wrinkles of the paper do not occur and high quality fixing can be realized. It is possible to provide a fixing device that can perform the fixing.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a continuous paper printing apparatus.

FIG. 2 is a side view showing an embodiment of the fixing device of the present invention.

FIG. 3 is a perspective view of a main part showing an embodiment of the fixing device of the present invention.

FIG. 4 is a side view of a cam portion.

FIG. 5 is a perspective view of an alignment member.

[Explanation of symbols]

10a: heating roller, 10b: pressure roller, 101a,
101b: Bearing, 15, 16: Arm, 16a: Cam follower, 17: Pressure adjusting screw, 18: Lock nut, 1
9: Spring holder, 20: Coil spring, 21
... Cam, 23 ... Frame, 25 ... Axis, 26 ... Encoder, 27 ... Sensor.

Claims (1)

[Claims] 1. A bearing holding portion for holding bearings provided at both ends of a pressure roller, and provided rotatably with respect to a frame around a shaft provided in parallel with a rotation axis of the pressure roller. A fixing device comprising: an arm member; a cam follower provided in a part of the arm member; a cam provided in contact with the cam follower; and a rotatable shaft member supporting the cam. The cam has a through hole through which the shaft member is inserted,
A groove formed in a part of the through hole so as to protrude in the radial direction of the through hole, and a positioning member used as a jig when the cam is mounted on the shaft member. And a hole formed.