JPH0142109Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixing device for fixing unfixed toner in a copying machine, and particularly to an improvement of a fixing device using a heat roller with a built-in heater or the like.

2. Description of the Related Art Conventionally, as a fixing device for a copying machine, there is one that uses heat rollers in which a heater is installed inside the rollers that are pressed together. This has advantages over fixing devices that perform heat fixing using other heat sources, such as good thermal efficiency and compactness.

The above heat roller has a halogen lamp installed in the center of a cylindrical roller made of aluminum, and is pressed into contact with a heat roller whose surface is coated with silicone rubber or whose surface is coated with Teflon (registered trademark) resin. It consists of a silicone rubber pressure roller. This pressure roller is brought into contact with the heat roller with an appropriate pressure, thereby creating a nip width of several mm at the pressure contact portion. The toner image transferred onto the paper is fixed in this nip width portion. In order to achieve good fixing, the above-mentioned nip width is important, and to obtain this, the heat roller portion is pressed with a pressure of several tens of kilograms using a pressure roller. The nip width is the width at which both rollers come into contact with each other.

Here, when the heat roller is rotating, even if a pressure of several tens of kilograms is applied between the two rollers, there is no problem such as deformation of the roller. However, when the rollers stop, tens of kilograms of pressure is always applied to the same part. This caused problems such as deformation of the roller itself. Therefore, the roller itself may be made of a material that does not deform. However, due to fixing properties, offset prevention, etc., not just any material can be used, but the materials are regulated. Therefore, there is currently no good means to overcome the above-mentioned drawbacks.

In addition, the nip width is several mm due to the pressure of several tens of kilograms applied between the upper and lower rollers, and the heat roller is connected to the motor and other devices via the drive transmission system.
When a paper jam occurs in a state where the paper is caught between the two rollers, it is necessary to use considerable force to manually rotate the rollers in order to remove the jammed paper. Therefore, the operation of removing the paper is very troublesome and requires a lot of time.

The present invention has been developed in view of the above-mentioned drawbacks. One of the rollers constituting the heat roller is provided so that it can come into contact with and separate from the other roller, and the roller that can come into contact with and take away from the other roller can be operated by turning the power switch ON and OFF. For example, when the copying machine is not in use (not in use), the two rollers forming the heat roller are separated in conjunction with the operation of turning off the power switch.

The heat roller fixing device of the present invention will be described in detail below with reference to the drawings.

1 and 2 are side views showing a heat roller fixing device according to the present invention, with FIG. 1 showing the copying machine in a used state, and FIG. 2 showing the copying machine in a non-use state. Moreover, FIG. 3 is a top view showing a state in which the upper heat roller constituting the heat roller is omitted. In the figure, reference numeral 1 denotes a heat roller in which a halogen lamp 2 is provided inside an aluminum pipe whose surface is coated with a resin serving as a toner release member, such as Teflon (trade name) resin. This heat roller 1 is configured to be rotationally driven, and the halogen lamp 2 inside is fixed. The pressure roller 3 that comes into pressure contact with the heat roller 1 has a core surface coated with silicone rubber and is held rotatably. That is, bearings 5 are attached to both ends of the rotating shaft 4 of the pressure roller 3 by bearing retainers 6, and the bearing retainers 6 are fitted into guide holes 8 of both frames 7. The guide hole 8 is formed into an oval shape so that the pressure roller 3 can be moved up and down. It also supports the pressure roller 3,
In order to press the heat roller 1, a pressure lever 10 is provided, one end of which is supported by a shaft 9 on the frame 7, and the bearing holding member 6 of the rotating shaft 4 is supported in the recess of the pressure lever 10. There is. A spring 11 is attached to the center of the pressure lever 10, and the pressure roller 3 is brought into pressure contact with the heat roller 1. In other words, the pressure roller 3
is regulated in the lateral direction by the guide hole 8, the downward direction by the pressure lever 10, and the upward direction by the heat roller 1, and is pressed against the heat roller 1 by the biasing force of the spring 11.

On the other hand, the pressure contact lever 10 is provided with a roller portion 13 rotatably provided on a shaft 12 at the opposite end of the shaft support. Opposing this roller part 13, an operating lever 17 is provided which rotates a pressure lever fixed via a boss 16 to both ends of a shaft 15, one end of which is rotatably provided in the frame 7 via a bearing 14. It is being One end of the operating bar 17 extends to the outside of the copying machine body through the bent portion 7a of the frame 7, and an operating knob 18 is attached to the tip thereof. Below operation knob 18
The operating lever 17 to which is attached is referred to as an operating lever. The operating lever 17 comes into contact with the roller part 13,
By pushing up, the pressure lever 10 is rotated against the spring 11, and the pressure roller 3 is separated from the heat roller 1. In this case, the pressure lever 10 is also rotated at the same time in the operating lever 17'. A guide pin 19 is fixed in the middle of the operating lever 17, and this guide pin 1
A rod-shaped spring 20 is provided in contact with 9. Both ends of the rod-shaped spring 20 are fixed to one of the frames 7, and are appropriately uneven. That is, the rod-shaped spring 20 positions the operating lever 17 by bringing the concave portion into contact with the pin 19.
It has two recesses and restricts the position of the operating lever 17 at two locations. As shown in FIG.
The operation lever 17 is structured so that it does not come into contact with the roll portion 13 of the pressure lever 10 when the pin 19 is locked in the recess at the top of the pressure lever 10 . Therefore, the structure is such that the pressing force of the pressing roller 3 is not regulated by the operation lever 17.

In the heat roller configured as described above, the operation lever 1
A power switch 21 is provided for controlling the supply of power to the main body of the copying machine in relation to the vertical movement of the main body of the copying machine. This power switch 21 is connected to a power circuit for supplying power to the copying machine, and its operating piece 22 is fixed to the frame 7 at a position where it is in contact with the operating lever 17. In FIG. 1, when the operating lever 17 is in the upper position, the operating piece 22 of the switch 21 is pressed to turn on the power.

The operation of the above-mentioned structure will be briefly described below.

If you are not using the copying machine now, use the operation lever 17.
Press down. In this case, the guide pin 19 of the operating lever 17 comes off from the recess of the rod-shaped spring 20, and
By passing over the convex part, it is locked in the concave part at the bottom. Therefore, the operating lever 17 is located in the state shown in FIG. 2 and is fixed in that position. As a result, the operating piece 22 of the power switch 21 moves away from the operating lever 17, and the power supply to the copying machine is cut off. At the same time, the roller portion 13 of the pressure lever 10 is pushed down by the operating lever 17 and the operating lever 17', and the pressure lever 10 is rotated against the biasing force of the spring 11. Therefore, the shaft 4 of the pressure roller 3 moves down along the guide hole 8, and the pressure roller 3 separates from the heat roller 1. Therefore, the power supply of the copying machine
When it is OFF, no pressure is applied between the heat rollers 1 and 3, which prevents the rollers from deforming.

On the other hand, when using a copying machine, the operation lever 17
If you push up the guide pin 19 and bar spring 20
The operation lever 17 is held in the position shown in FIG. As a result, power switch 2
1 turns on when its operating piece 22 is pressed,
Power is supplied to the copying machine. Also, the pressure lever 10
is rotated upward by the biasing force of the spring 11, and presses the pressure roller 3 against the heat roller 1. At this time, since the operating lever 17 is structured to be held at a position where it does not come into contact with the roller portion 13 of the pressure lever 10, the pressure lever 10 is
The urging force of 1 is not limited and the pressure contact roller 3 is applied as it is.
is brought into pressure contact with the heat roller 1. Therefore, the pressure lever 10 applies pressure to the pressure roller 3, causing the heat roller 1 to press against the pressure roller 3 with a pressure of several tens of kilograms, resulting in a nipple width of several mm.

As explained above, according to the fixing device using a heat roller of the present invention, both rollers constituting the heat roller are brought into pressure contact with each other with appropriate pressure in response to power-on when the copying machine is in use, and when the copying machine is not in use, Since the rollers are separated from each other when the power is turned off, it is possible to prevent the rollers from being deformed by pressure. In addition, the structure is such that both rollers are brought into contact and separated at the same time in conjunction with the power ON/OFF operation, so when the power is turned on, the rollers are brought into pressure contact, and when the power is turned off, the rollers are separated. This not only makes the configuration extremely simple, but also allows the rollers to be reliably pressed or separated when the copying machine is in use and when it is not in use. Paper jammed in between can also be easily removed.

[Brief explanation of the drawing]

1 and 2 are side views showing the heat roller fixing device of the present invention, in which FIG. 1 shows the copying machine in use, FIG. 2 shows the copying machine in non-use, and FIG. 3 shows the copying machine in non-use. FIG. 2 is a top view of the heat roller fixing device according to the present invention. 1...Heat roller, 2...Halogen lamp,
3... Pressure roller, 4... Rotating shaft, 8... Guide hole, 10... Pressure lever, 11... Spring,
17... Operation lever (pressure lever operation lever),
19...Pin with guide, 20... Rod-shaped spring, 21... Power switch.

Claims (1)

[Claims for Utility Model Registration] In a heat roller fixing device that thermally fixes unfixed toner by being pressed against each other, a support means for supporting one roller constituting the heat roller so as to be able to move toward and away from the other roller; A manual operation means that is linked to the support means and has one end protruding outside the copying machine main body and presses or separates the two rollers; and a manual operation means that moves the support means to press or separate the rollers. A power switch which is arranged to supply or cut off power to the power circuit of the copying machine main body, and which turns on the power when the two rollers are brought into pressure contact with each other by the operating means, or turns off the power when the two rollers are separated. A heat roller fixing device characterized by comprising: and.