JPS594703B2 - Fusing device for copying machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a roller pressing device and a release device for a fixing device for a copying machine.

In an electrophotographic copying machine, a roller-type fixing device is used to fix the toner image on the copy paper to the transfer paper.

3 One of these rollers is a fixing roller with a built-in heater, and the other is a pressure roller for the fixing roller.

This pressure roller often uses an elastic body to make the fixing effect effective, so if the pressure roller is pressed against the fixing roller in a stationary state after the fixing is completed, or if the roller stops rotating due to a power outage etc. while the machine is operating. In some cases, only a portion is heated, causing deformation and adversely affecting the subsequent fixing effect. The present invention provides a fixing device for a copying machine in which a second roller (for example, a pressure roller) is provided to be capable of pressing and releasing the pressure on a first roller (for example, a fixing roller) that is rotatably provided and has a fixed position. , the planetary idler gear is moved over a certain range around a gear provided on the roller shaft as the first roller rotates, and the planetary idler gear is provided so that the momentum thereof can be used to displace the position of the second roller. When the first roller is not rotating, the planetary idle gear is pressed by the weight of the second roller and/or the urging force of the urging means. By moving the rollers in the opposite direction, the pressure bond between the two rollers is released.
This was done to eliminate the above drawbacks, that is, to prevent damage to the rollers.

Next, examples of the present invention will be described.

FIG. 1 is a central sectional view of an embodiment of the invention.

FIG. 2 is a side view of an embodiment of the invention. FIG. 3 is a schematic perspective view of an embodiment of the invention.

The fixing roller 1 has a heat source element 30 inside, and is connected to a side wall 2 by a fixing roller bearing 2 and a fixing roller bearing housing 3.
4 and 25. The rotational movement is obtained by the fixing roller gear 4. A constant friction is applied by a cleaning brush or friction device 33. The pressure roller 5 is attached to a pressure roller lever 8 via a pressure roller bearing 6 and a pressure roller bearing housing T. The pressure roller lever 8 is mounted so as to be rotatable about a shaft 9 fixed to the side wall 24.
A pressure roller lever pin 10 fixed to the other end rotatably attaches a pressure roller lever connecting plate 11. The pressure lever 13 is rotatably mounted around the axis of the fixing roller as a fulcrum.

A pressure roller lever connection plate 11 is rotatably attached to a connection plate pin 12 fixed to one end of a pressure lever 13.

The crimp lever 13 has a long hole at its lower end and is guided and held by a shaft.

Planetary idle gear shaft 15 fixed to drive gear board 16
and the crimp lever 13 are loosely matched.

The planetary idle gear 14 is rotatable with respect to the planetary idle gear shaft 15 and meshes with the fixing roller gear 4 and the drive gear 17. The drive gear 17 is connected to the left and right drive gear boards 16.
It is fixed to a drive shaft 19 passing through a bearing.

The drive gear 17 is constructed integrally with the drive sprocket 18.

The drive gear board 16 is held in a rotatable and slidable state by a long groove formed at one corner of the triangle.

The dynamic gas projector 21 and the dynamic joint 22 are fixed to a single shaft that passes through a bearing provided on a retaining plate that is firmly supported by a side wall 24 and a column.

A roller chain 20 is attached to the drive sprocket 18, the dynamic gas sprocket 21, and the tension sprocket 35. Next, the operating principle will be explained.

Power from the main motor is transmitted to the drive sprocket 18 through a dynamic joint 22 and a dynamic gas proget 21. (The rotation direction is counterclockwise in the side view.) Since the drive sprocket 18 and the drive gear 17 are integrated as shown in FIG. 3, the left and right drive gears 17 rotate, and the planetary idle gear 14 through fixing roller gear 4
Try to rotate. (The rotation direction is counterclockwise in the side view.) Since a constant friction is applied to the fixing roller 1 by a friction device (including the case where it depends on a cleaning device), the planetary idle gear 14 is connected to the axis of the fixing roller 1. The fixing roller makes a planetary motion around the fixing roller gear 4 with the core as the center.

(The direction of movement is clockwise in the side view.) Following the planetary motion of the planetary idle gear 14, the drive board 16 to which the planetary idle gear shaft 15 is fixed is driven by a long groove formed in one triangular corner of the drive board 16. Performs rotational and sliding movements.

Further, the pressure lever 13 rotatably attached to the planetary idle gear shaft 15 rotates about the axis of the fixing roller 1.

(The rotational direction is clockwise in the side view.) The rotational movement of the pressure lever 13 lifts one end of the pressure roller lever 8 via the pressure roller lever connection plate 11 and presses the fixing roller 1 and the pressure roller 5 together.

When the main switch is turned off or turned off and all operations are stopped, the pressure roller 5 releases the pressure bonding due to its own weight.

In order to reduce the weight, if the pressure roller 5's own weight is not sufficient to release the pressure, a spring can be provided at an appropriate location to release the pressure.

The resting position of the planetary idle gear 14 during operation is a position where the load rotational torque of the fixing roller 1 and the rotational torque of the planetary idler gear 14 are balanced, if the weight of the rollers, gears, etc. is ignored.

Since the planetary device provided on the side wall 24 side is also provided on the side wall B25 side, the pressure roller 5 can be pressed in parallel to the fixing roller 1 or separated from it.

The pressing pressure increases or decreases depending on the magnitude of the friction acting on the fixing roller.

Therefore, the crimping pressure can be adjusted by adjusting the friction. Also, the friction increases or decreases depending on the thickness of the paper passing through. That is, when the paper thickness is thick, the friction becomes large and the pressing pressure becomes large, which is advantageous for fixing. The pressing pressure can also be kept constant by providing an adjustment pin that stops the vertical movement of the pressing roller lever 8 at an arbitrary position. Because of the above structure, the cost is lower than the conventional device using a motor and cam because no expensive parts are used.

The planetary idle gear can be placed anywhere on the circumference of the fixing roller gear, which is advantageous in terms of design.

Therefore, this is an extremely excellent invention that can provide at a low cost a device for ensuring the function of preventing aging and thermal deterioration due to pressure bonding between the fixing roller and the pressure roller when the switch is turned off.

[Brief explanation of the drawing]

FIG. 1 is a central sectional view of an embodiment of the invention. FIG. 2 is a side view of an embodiment of the invention. FIG. 3 is a schematic perspective view of an embodiment of the invention. 1 is a fixing roller, 2 is a fixing roller bearing, 3 is a fixing roller bearing housing, 4 is a fixing roller gear, 5 is a pressure roller, 6 is a pressure roller bearing, 7 is a pressure roller bearing housing, 8 is a pressure roller lever 9 is a pressure roller Lever shaft, 10 is pressure roller lever pin, 11 is pressure roller lever connection plate, 12 is connection plate pin, 13 is pressure bonding lever, 14 is planetary idle gear, 15 is planetary idle gear shaft, 16 is drive gear board, 17 is Drive gear, 18 is a drive sprocket, 19 is a drive shaft, 20 is a roller chain, 21 is a dynamic gas proget, 22 is a dynamic joint, 24 is a side wall A, 25 is a side wall B, 28 is a heat source holding shaft, 29 is a heat source A holding plate, 30 a heat source element, 33 a cleaning brush (or friction device), and 35 a tension sprocket.

Claims (1)

[Claims] 1. In a fixing device for a copying machine, in which a second roller is provided to be able to press and release pressure against a first roller that is rotatably provided and has a fixed position, as the first roller rotates, the roller axis The planetary idle gear is moved over a certain range around the gear provided above, and the momentum is transmitted via an interlocking means to a lever provided to displace the position of the second roller. The rollers are crimped, and when the first roller is not rotating, the planetary idle gear is moved in the opposite direction by the weight of the second roller and/or the urging force of the urging means. A fixing device for a copying machine, characterized in that the pressure bonding of a roller is released.