JPS58132770A - Fixation device - Google Patents

Abstract

PURPOSE:To exactly attain effective utilization of a cleaning web, by providing a means which detects the end of the web before the end of the cleaning web is separated from a fixing roller to stop winding of the web, and to display its stop. CONSTITUTION:When a notch 8a provided at a position near by the end of a web 8 is moved, a pin 26 fixed onto a rocking lever 24 falls into this notch 8a, and the lever 24 rotates clockwise by operation of a spring 25. At the same time the pin 26 pushes up a groove hole 27 of a rocking plate 16 to rotate the rocking plate 16 counterclockwise, detaches an intermediate gear 17 from a driven gear 20, and stops transfer of rotation to the driven gear 20. When the web approaches the end of winding of the cleaning web after reciprocating once, and a notch 8b of the web comes to a position of an actator 28 of a microswitch 29, the actuator 28 goes into the notch 8b to stop driving of a motor 13, to stop winding of the web, and to display a stop of the web in the way.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixing device in a toner image forming apparatus such as a photocopier.

Conventionally, various types of fixing devices have been used in such image forming apparatuses, but from the viewpoint of landing efficiency and safety,
Heat roller fixing devices are the mainstream. In a heat roller fixing device, the toner image holding material with a toner image formed on its surface is in direct contact with the high temperature fixing roller, so efficiency is high and the feeding of the toner image holding material is performed stably. . However, due to the nature of toner, the toner on the toner image holding material tends to be offset to the fixing roller, so offset can be prevented by applying an anti-offset agent such as silicone oil to the surface of the fixing roller, or offset can be prevented by applying an anti-offset agent such as silicone oil to the surface of the fixing roller. It is necessary to wipe off the toner that has been stained. One such fixing device uses a cleaning web impregnated with an anti-offset agent such as silicone oil to rub the surface of the fixing roller to apply the anti-offset agent to the surface of the fixing roller. There is a heat roller fixing device that cleans the toner that has been offset and dissipated on the fixing roller. An example of such a heat roller fixing device is shown in Figure 1. In the figure, 1 is the fixing roller and 2 is the pressure roller. roller, 3 is a guide that guides the toner image holding material between both rollers; 4 and 5 are separation claws that prevent the toner image holding material from wrapping around the roller; 6
and 7 indicate discharge rollers for feeding out the toner image bearing material.The fixing roller 1 has a surface layer of a material of the tetrafluoroethylene type, known by the trade name of Teflon, for example, and has heaters H, H! have. For example, the heater HIFi high temperature heater has a wattage of 720W,
The heater is an H8 low temperature heater with a power output of 80W. The pressure roller 2 has a surface layer of, for example, PUM,
It has a heater US inside. The heater H1 has a power output of, for example, 50W. During fixing, the toner image holding material is fed from the left side of the figure along the id 3, and
and 20 and is heated and fixed, and is prevented from being wrapped around the roller by separation claws 4 and 5, and is then heated and fixed on the discharge roller 6.7.
Sent by.

In the above heat roller fixing device, the toner on the toner image holding material (hereinafter referred to as copy paper) is prevented from being offset to the fixing roller, and when offset occurs, the offset toner is removed and the fixing roller is moved. For cleaning, a long cleaning web 8 is placed so as to rub the surface of the fixing roller 1. The cleaning web 8 is mounted on shafts 9 and 10 that rotate at a very slow speed.
It is pressed against the fixing roller 1 with an appropriate pressure by a porous roller 11. The cleaning web 8 is impregnated with an anti-offset agent, such as silicone oil, and this cleaning web forms a silicone oil layer that leads to the surface of the fixing roller l, and at the same time wipes away toner and dirt offset on the surface of the fixing roller l. It also serves to absorb excess silicone oil.

When the toner is wiped off, since the toner is soft, it is easily wiped onto the web, and as it is wound up, it is fixed on the web so that it does not transfer elsewhere. Further, although the web is wound up while containing excess silicone oil, the excess oil scraped off by the heat of the fixing device evaporates, and the web can be used multiple times. In FIG. 1, numeral 12 is a thermistor for detecting the surface temperature of the fixing roller, which controls the surface temperature of the fixing roller to an appropriate temperature, for example, 185.degree.

Conventionally, in a fixing device in which the offset prevention agent is applied to the fixing roller and the fixing roller is cleaned using a leaning web, the long web 8 is placed on one shaft, that is, the supply shaft 9. Rolled IJ
After the cleaning web is wound onto the other shaft, namely the winding shaft 10, and the entire length of the cleaning web is wound onto the winding shaft 10, these shafts are replaced with new ones. In this way, when the long web 8 is fed between the take-up shaft lO and the supply shaft 9, the feed speed is set to 9.
Although it is possible to feed the web regardless of the diameter of the web, the web feeding mechanism becomes complicated and expensive. It is wound from shaft 9 to shaft 10.

In such a fixing device, cleaning urchin! If the web is completely wound around the shaft 10, after the end of the web leaves the fixing roller, the porous roller 11 will come into direct contact with the surface of the fixing roller 1, which will stain the surface of the roller 11 and cause blood to flow. Unable to withstand continuous use. Therefore, in the past, people had to find a suitable time and replace it early, which resulted in a lot of waste and if they forgot to replace it, they ended up having to replace Pumrolla 11 as well.

The present invention aims to provide a fixing device that eliminates the above-mentioned inconveniences in conventional devices, prevents the waste of having to replace the dem roller, and makes effective use of the cleaning web. It is something.

The invention will be explained below with reference to the drawings. FIG. 2d shows an embodiment of a cleaning web used in the apparatus of the present invention. As shown in the figure, this cleaning tool 8 has a notch 8a detected by the detection means before the end thereof.
When the cleaning web is wound in the opposite direction, a similar notch 8b is formed before the end of the cleaning web.

An embodiment of a means for detecting the end of the cleaning web when winding it, stopping the winding of the web, and indicating the stop is shown in FIGS. 3 and 4. The cleaning web is wound up from the shaft 9 to the shaft lO, and at the end of the winding, the winding direction of the cleaning web is reversed, and then the cleaning web is wound up.

The web is increased again by 9 KIJ, the end of the web is detected, that is, the starting end of the first winding is detected, and the winding of the web is stopped and the stop is displayed.

In FIG. 3, reference numeral 13 indicates a synchronous motor for driving, and 14 indicates an output shaft of the motor 13. A drive gear 15 is fixed on the output shaft 14 of the motor 13, and a swing plate is mounted on the output shaft 14. 16 is mounted so as to be able to swing left and right about the shaft, and an intermediate gear 17 that constantly meshes with the drive gear is supported on the swing plate 16 by a shaft 18. Shafts 9 and 10 on which the cleaning web 8 described above is wound
Driven gears 19 and 20, which can mesh with the intermediate gear 17, are fixedly attached to the intermediate gears 17, respectively.

In order to hold the oscillating plate 16 in a position where the oscillating plate 16 is oscillated to the left or right so that the intermediate gear 17 meshes with the driven gear 19t or 2°, the axis of the intermediate gear 17 is 18
A tension spring 22 is tensioned between the pin 21 and the pin 21 provided below the output shaft 14 of the motor 13. A swing lever 24 that can swing 11 times around a shaft 23 fixed to the fixing device is disposed on one side of the swing plate 16.
4 is always subjected to a clockwise rotational force by a spring 25 connected to one end thereof. A pin 26 is attached to the other end of the lever 24 of the upper Nc, and this pin 26 hits the edge of the cleaning web 8 and holds the lever 24 against the force of the nonone 25. When the notch 8a comes, the lever 24 is caught in the notch 8a, and the lever 24 is rotated clockwise by the force of the spring 25. The swing plate 6 is formed with an oblique slot 27 that engages with the pin 26.

Further, on the other side of the swing plate 16, a microswitch 29 having an actuator 28 positioned so as to fit into the other notch 8b of the web 8 is arranged.

In the above device, as shown in the third panel, the intermediate gear 17
When the motor 13 is driven with the motor 13 engaged with the driven gear 20, the shaft 10 moves the cleaning web rotated in the direction shown by the arrow onto the shaft 10 via the driving gear 15, the intermediate gear 17, and the driven gear 20. Wind it up. When the notch 8a provided near the end of the web 8 comes, the swing lever 24
The pin 26 fixed above falls into this notch 8aK,
The lever 24 rotates clockwise under the action of the spring 250.

At the same time, the pin 26 pushes up the slot 27 of the rocking plate 16, so the rocking plate 16 rotates counterclockwise and pulls the intermediate gear 17 away from the driven gear 20.
Stop transmitting rotation to. When the spring 22 passes through the output shaft 14 of the motor 13, that is, the center of rotation of the rocking plate 16, the spring 22 acts to pull the rocking plate ]6 to the opposite side, and the rocking plate 16 moves to the left. The intermediate gear 17 meshes with the driven gear 19. Therefore, the rotational force is transmitted to the driven gear 19, and the cleaning web 8 is wound around the shaft 9, and the web, on which toner has been fixed to some extent, cleans the surface of the fixing roller. is applied and excess oil is absorbed. After the web makes almost one reciprocation and approaches the end of winding of the cleaning web (starting end of the first winding of M), the notch 8b of the web touches the actuator 28 of the microswitch 29.
When the actuator 28 reaches the position , the actuator 28 enters the notch 8b and stops driving the motor 13 to stop winding the web, and also indicates that the web has stopped. An example of a circuit that performs such a stop and display is shown in FIG. 4. In FIG. 4, 13 is a motor, 29 is a microswitch, 30 is a power source, and 31 is an indicator light for indicating a stop.

As mentioned above, if such a fixing device does not have a means to detect the end of the cleaning web and stop winding, the cleaning web will be completely unwound onto the shaft 1 (NC) and the porous When the rubber opening 6°-ra 11 comes into contact with the surface of the fixing roller 1, the surface of the rubber roller 11 gets dirty and becomes grooved, making the rubber roller unusable. There is a lot of waste because the rubber roller has to be stopped and replaced, and if the opportunity to stop is lost, the cost of replacing the rubber roller is incurred.

However, in the present invention, there is no sea urchin between the rubber roller 11 and the fixing roller l. Since the motor 13 is stopped before the accident occurs, such an accident can be prevented. Looking at the web shown in 2nd page 1, the web starts using the force at part A, moves to part B, then reverses, and stops at part C. To replace the web, pull up the web unit W at position 1 indicated by the two-dot chain line in Figure 81. At this time, press the micro switch 29.
Palm 9-24 remains on the side of the foot holder, so if you set a new web in the set position, toshi, web unit, and to, each will be reset and the motor 13 will be turned on.
The web is wound onto the shaft 10. FIG. 5 shows another embodiment of the invention. This has an extremely simple structure, and by detecting the diameter of the web using a micro switch 32, the end of the web is detected and the winding of the web is stopped. A circuit lights up an indicator light to indicate a stop. Although this embodiment lowers the detection accuracy Fi, it has the advantage of being simple and inexpensive to manufacture.

In the above explanation, an embodiment was mainly described in which the web is sent in one direction and wound up. However, the web may be sent back and forth once, or it may be detected that the web has returned to the starting end side and then the web is rotated in the normal direction again. In addition, in the above embodiment, an example was shown in which the end and start ends of the web were detected using notches, but markings were provided on the web and this could be detected using a photo sensor. Of course, it is also possible to detect by using a conductive part, by applying a conductive part and detecting by using a contact, or by detecting that the rotation of the shaft around which the web is wound has stopped.

According to the above embodiment, since the cleaning web is completely wound around the shaft and separated from the fixing roll, the rubber roller is prevented from becoming contaminated and has to be replaced, and the cleaning web is The cleaning web can be used effectively up to the end, making it possible to use the cleaning web economically. Also, when the cleaning web stops, this is displayed, making it easy to confirm that the web should be replaced. be done.

As mentioned above, the present invention ensures effective use of the cleaning web! It is something that can be achieved.

[Brief explanation of drawings]

FIG. 1 is a side view showing an outline of a roller fixing device, FIG. 2 is a view showing an example of a cleaning web used in the fixing device fitK according to the present invention, and FIG. 3 is a side view showing an embodiment of the present invention. , FIG. 4 is an explanatory diagram of a circuit used in the apparatus shown in FIG. 3, and FIG. 5 is a side view showing another embodiment of the present invention. 1... Fixing roller Pressure roller for 2 3... Guide 4.5... Separation claw 6.7... Discharge roller 8... Cleaning web 9.10... Shaft 11... Rubber roller I2
...Thermistor 13...Motor]4...Output shaft ]5...Drive gear 16...Winging plate
17... Intermediate gear 18... Shaft
19, 20... Driven gear 21... Bin
22...Tension spring 23...Shaft 24
... Swinging lever 25 ... Spring 26 ...
・Bottle 27... Slot 28... Actuator 29... Micro switch 30... Power supply 31... Indicator light previous time 4

Claims (1)

[Claims] In a fixing device in which both ends of the cleaning web that rubs the surface of the fixing roller are wrapped around a shaft, and the cleaning web is wound from one shaft to the other shaft, the cleaning web is unloaded before the end of the cleaning web leaves the fixing roller. Detect the end of the signal and urchin! 7Ilif device characterized by having a means for stopping the winding and indicating the stop.