JPS6055370A - Roll fixing device of copying machine - Google Patents

Abstract

PURPOSE:To prolong rolls and bearings in life by switching the contacting state of a heat roll and a pressure roll between a warm-up and fixation stand-by state time and a fixation time. CONSTITUTION:The heat roll 5 and pressure roll 6 are rotated counter clockwise around a shaft 9 as a fulcrum in the warm-up and stand-by state by drawing the other end part of a bearing frame 8 downward with a spring 10, and heated in a light contacting state. On the other hand, the outer circumference of a cam 13 presses a cam follower 11 during fixation according to the rotation of a shaft 12 to rotate the bearing frame 8 clockwise around the shaft 9 as a fulcrum against the elastic force of the spring 10. Consequently, the pressure roll 6 provided to the bearing frame 8 is pressed against the heat roll 5 to enter an optimum heating and pressure state for the fixation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat roll fixing device @IC for a copying machine.

(Prior Art) As shown in FIG. 1, a conventional heat roll fixing device for a copying machine is composed of a heat rule 2 and a pressure roll 3, each of which has a built-in heater rod 1, which is provided in an upper and lower pair. and 3 were rotated in an open and pressed state during fixing in order to uniformly heat them during warm-up and standby states.

For this reason, a large load is applied between the p-ru and this p-ru even at times other than fixing.
The drawback was that it shortened the life of the bearings attached to the shaft of the motor.

(Object of the Invention) The present invention has been made to eliminate the drawbacks of the conventional heat rule fixing device described above.
The contact state between the pressure roll 3 and the pressure roll 3 can be arbitrarily switched between warm-up and fixing standby states and during fixing, thereby extending the life of the rolls and bearings, reducing maintenance and inspection intervals, and saving resources. It is an object of the present invention to provide a roll fixing device for a copying machine which is also useful.

(Structure of the Invention) For this purpose, the present invention makes it possible to move up and down one or both of the heat rolls and pressure rolls provided in the upper and lower pair using an appropriate lifting means, and to lightly touch them during warm-up and standby states. At the same time, during fixing, both of these plates can be brought into contact with each other in an optimal state for fixing.

(Embodiments) The present invention will be described in detail below based on embodiments shown in the drawings.

FIGS. 2 and 3 are schematic configuration diagrams showing one embodiment of the heat roll fixing device of the present invention, and are side views showing the state of use thereof.

In these figures, heat rolls 5 and pressure rules 6 are placed in a pair of upper and lower heater lots M in heater lot 4.
Among these, the heat meal 5 is fixed to a device frame (not shown). On the other hand, the pressure roll 6 has both ends of its shaft 7 rotatably attached to a suitable position between two bearing frames 8, and one end of the bearing frame 8 is connected to the equipment frame (not shown) via a shaft 9. The bearing frame 8 is rotatably attached to the bearing frame 8, and a tension spring 10 is provided at the other end of the bearing frame 8, so that the tension spring 10 is always pulled downward 3. On the other hand, a cam follower 11 is provided at a suitable location between the other end of the bearing frame 8 and the shaft 7 of the pressure roll 6, and a shaft 12 is provided below the cam follower 11 separately from the bearing frame 8. The cam 13 is rotatably arranged, and the cam follower 1 is arranged around the outer periphery of the cam 13.
By pressing 1, the bearing frame 8 is rotated about the shaft 9 against the elasticity of the 1-tension spring 100, thereby bringing the contact state of the pressure roll 6 against the heat rule 5 into warm-up and standby states. At times, the contact is weak as shown in FIG. 2, and during fixing, the contact is strong as shown in FIG. And this cam 13
As a means of operation, a sensor that detects the leading edge of the paper is placed in the paper transport path provided from the transfer section of the photoreceptor (not shown) to the output tray outside the machine, and the signal detected by the sensor is used to detect the appropriate This can be done by intermittently rotating the shaft 12 of the cam 13 using a suitable controller.

The present invention is constructed as described above. Next, its operation will be explained.

Heat rule 5 during warm-up and standby state
As shown in FIG. 2, the bearing frame 8 is pulled downward at the other end by a spring 10, and the shaft 9 rotates counterclockwise in the figure as a fulcrum, and the pressure roll 6 makes light contact. It is heated in a state where it is heated.

On the other hand, during fixing, the outer periphery of the cam 13 presses the cam follower 11 as the shaft 120 rotates, as shown in FIG.
By resisting elasticity and rotating clockwise in the figure using the shaft 9 as a fulcrum, the pressure tool 6 provided on the bearing frame 8 is brought into pressure contact with the heat 11 5, which is ideal for fixing using heating and pressure. It becomes a state. A sheet of paper with an unfixed toner image transferred thereto is conveyed from the transfer section of the photoreceptor in the direction shown by arrow A, and is heated and pressurized by the heat roll 5 and pressure roll to fix the image. It is transported in the direction of arrow B.

(Effect of the invention) The present invention is configured and operates as described above,
By arranging the pressure roll 6 so as to be able to move up and down relative to the heat roll 5, the load can be kept small by weakening the contact state of 1lff-'/cm between both during warm-up and standby states. Therefore, compared to the conventional heat roll and pressure roll that are constantly pressed together under a large load, the roll,
Not only can the life of the bearings installed on the shaft of the roll be extended, but also the load on the motor that drives them can be reduced, resulting in less power consumption, which means longer maintenance and inspection intervals. This has the effect of providing a p-ru fixing device that is useful for saving resources and energy.

It should be noted that there is no reason why the present invention should be limited to the above-mentioned embodiments. For example, the roll that is moved up and down in order to change the strength of the contact between the heat roll 5 and the pressure roll 6 may be replaced by the heat roll 5 instead of the pressure roll 6. Alternatively, instead of moving the front bearing frame 8 up and down using a cam follower 11 and a cam 13, the vertical movement means may be a mechanism suitable for the shafts of the heat roll 5 and the pressure roll 6. It goes without saying that the timing may be determined using a latch or the like.

[Brief explanation of drawings]

FIG. 1 is a schematic layout diagram showing the arrangement of a heat roll and a pressure roll in a conventional roll fixing device, and FIG. 2 is a schematic configuration diagram showing an embodiment of the roll fixing device of the present invention, in which warm-up and pressure rolls are arranged. FIG. 3 is a side view showing the state of contact between the heat roll and the pressure rule in the standby state, and FIG. 3 is a side view showing the state of contact between the heat roll and the pressure rule during fixing. In the diagram, 4...heater rondo, 5...heat rule,
6... Pressure roll, 7... Shaft, 8... Bearing frame, 9... Shaft, 10... Tension spring,
11...Cam follower, 12...Axis, 13...
cam. Patent applicant: Fuji Xerox Co., Ltd. Agent (6981) Susumu Horikoshi

Claims (1)

[Claims] In a p-ru fixing device in which a pair of upper and lower heat rolls and pressure rolls are provided,
A roll fixing device for a copying machine, characterized in that the heat rule or pressure roll is provided to be movable up and down, and the contact state thereof is weak during warm-up and standby states, and strong contact during fixing.