JPS628050Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a fixing device for a copying machine, and more particularly to a device for applying an anti-offset liquid to a fixing roller.

<Prior art> Conventionally, when a partially fixed toner image is fixed with a roller, such as a heat roller or a pressure fixing metal roller, the toner adheres to the roller and stains the copy surface with this toner (hereinafter referred to as the offset phenomenon). ) To prevent this, the rollers are coated with silicone liquid. This application method includes impregnating felt with silicone liquid and pressing it against a roller, or immersing a part of the cloth in a bath of silicone liquid and bringing the other end into contact with the roller. is used.

In particular, if the fixing roller is configured to constantly press the anti-offset liquid application means into contact with the fixing roller, when the anti-offset liquid impregnated in the application means runs out, it is replaced with a new one, for example. This exchange is often performed when the number of copies reaches a certain number. When the applicator was replaced in accordance with the number of copies to be made in this manner, it was often necessary to replace the applicator even though it was still sufficiently impregnated with the anti-offset liquid, or to replace it after offset, etc. had occurred. Therefore, it is extremely unstable to replace the coating means after a certain number of copies have been made, making copying unstable.

<Purpose of the invention> The object of the invention is to externally display the replacement time of the coating means for applying anti-offset liquid to the fixing roller, thereby enabling stable copying at all times.

In particular, an object of the present invention is to effectively detect when it is time to replace the coating means.

<Example> FIG. 1 is a sectional view showing an example of the present invention. 1 in the figure, a toner image is formed on the top surface,
Copy sheets 2 and 3 sent to the fixing section are made of a pair of heater lamps 6 and 7 arranged in hollow cylinders 4 and 5, respectively, and silicone rubber 8 and 9 coated on the surface of the hollow cylinders. This is a heat roller, and this roller constitutes a fixing section. One of the heat rollers 2 is provided with a coating material 10 impregnated with an anti-offset liquid in order to apply an anti-offset liquid (generally silicone liquid or the like) to the surface of the roller (silicon rubber 8). This coating material 10 is attached to a holding member 11. Further, the holding member 11 is rotatably supported at one end by a pin 12, and keeps the coating material 10 in pressure contact with the upper roller 2 at all times.

On the other hand, reference numeral 16 is a friction roller for detecting the application state of the anti-offset liquid, which is the main purpose of the present invention. The friction roller 16 is provided so as to lightly contact the surface of the upper heat roller 2. Details of the friction roller 16 are shown in FIG. In the figure, friction roller 16
connects its shaft 16a to both frame plates 16b, 16c.
The shaft 16a is rotatably held via bearings 16d and 16e, and a disc 17 is fixed to one end of the shaft 16a. A notch 18 is provided on the outer periphery of the disc 17 as shown in FIG. Further, a light emitting element 19 and a light receiving element 20 are provided to sandwich the disc 17 and face the notch 18 of the disc. The number of rotations of the friction roller 16 is detected by the light emitting element 19, the light receiving element 20, and the disc 17 having the notch 18, and the light receiving signal from the light receiving element 20 is input to the counter circuit 21. Therefore, the number of rotations of the friction roller 16 is detected by the counter circuit 21. Furthermore, the counter circuit 21 includes a friction roller 16
A control signal is output based on a change in the number of rotations of the friction roller 16, and when the number of rotations of the friction roller 16 exceeds a certain level, an indicator lamp 15 for instruction is turned on. still,
22 in the figure is a brake for the coating amount detection roller 16.

In the apparatus configured as described above, the friction roller 16 for detecting the amount of applied offset liquid is in light contact with the heat roller 2. An appropriate braking force is applied to the roller 16 by a brake 22. In this state, heat roller 2
When the silicone liquid is applied onto the surface using the coating material 10 that is constantly in pressure contact with the detection roller 16,
Does the roller 16 not rotate due to no frictional force?
Or the number of rotations is also very low. In this state, the signal from the light receiving element 20 is not inputted to the counter circuit 21 much, and since the rotation speed of the friction roller 16 is below the specified rotation speed, the counter circuit 21
Therefore, no control signal is output.

By the way, when the offset prevention liquid in the coating material 10 decreases, the supply of silicone liquid to the surface of the heat roller 2 decreases, and a frictional force acts on the friction roller 16.
It will rotate at approximately the same speed as the circumferential speed of. In this state, when the rotation speed of the friction roller 16 increases and exceeds the specified rotation speed A, the counter circuit 22
More signals are output. As a result, the lamp 15 is turned on, and the time to replace the coating material 10 can be notified.
Based on this notification, the coating material 10 can be replaced.
It becomes possible to always maintain the fixing roller in a stable state without making a mistake in replacing the coating material 10.

Note that the number of rotations of the friction roller 16 is counted over a relatively long period of time, for example, 10 seconds to 30 seconds, so it is an average value, and there is no possibility of malfunction due to temporary excessive rotation of the friction roller. .

<Effects of the invention> According to the offset prevention liquid coating device of the invention,
When the number of rotations of the friction roller that is in contact with the surface of the fixing roller exceeds a specified number of rotations, this is detected and a display means is driven to notify that it is time to replace the means for applying offset prevention liquid that is in contact with the surface of the fixing roller. Therefore, the timing for replacing the coating means can be kept stable. In other words, even if the lifespan of the application means at which it is time to replace them differs, it is possible to notify the appropriate time to replace them according to their lifespans.
No offset occurs due to the fixing roller, and the coating means can be replaced without waste.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention. FIG. 1 is a sectional view of the fixing section, FIG. 2 is a structural diagram for explaining details of the friction roller, and FIG. 3 is a sectional view of the fixing section. FIG. 3 is a plan view of a disk fixed to the shaft of the friction roller in FIG. 2; 1... copy paper, 2... heat roller, 10...
... Offset prevention liquid coating material, 15 ... Display lamp, 16 ... Friction roller, 17 ... Disc, 19
... Light emitting element, 20 ... Light receiving element, 21 ... Counter circuit.

Claims (1)

[Claims for Utility Model Registration] A fixing roller for fixing a fixed image, comprising: a coating member that is always in contact with the surface of the fixing roller and applies an anti-offset liquid to the surface of the fixing roller; a friction roller rotatably held in contact with the coated fixing roller surface; a rotation detection means for detecting the number of rotations of the friction roller; a display means for notifying replacement of the application member; and the rotation detection means. An anti-offset liquid coating device for a copying machine, comprising: a drive means for driving the display means for notifying replacement of the friction coating member by detecting a rotational speed of the friction roller that is equal to or higher than a specified number of revolutions.