JPS58200266A - Oil applying device of fixing device of copying machine - Google Patents

Abstract

PURPOSE:To supply and stop an oil surely, by arranging a bimetal, which opens and closes the supply position in accordance with the variance of temperature, in the position through which the oil is supplied from an oil tank to a fixing roll. CONSTITUTION:A hollow projecting part 41 which has the lower end opened is formed in the bottom part of an oil tank 4 to cover the overall length of a fixing roll 1, and the free end of a bimetal material 8 whose one end is fixed to the bottom part of the tank 4 is attached to an opening part of the upper end of the projecting part 41 so as to cover the opening part throughout, and a heater 9 for heating the bimetal 8 and the oil in the tank 4 is arranged near this free end. When the heater 9 is conducted electricity at a proper timing in consideration of characteristics of the bimetal 8, the heating function of the heater 9, etc. after the paper feed start of a copying machine, the oil in the tank 4 is heated, and the bimetal 8 is defomed as shown by a broken line, and the opening of the upper end of the hollow projecting part 41 is opened, and the oil is flowed down and is applied to the surface of the fixing roll 1 through an applying member 7. When the conduction of electricity to the heater 9 is interrupted, the bimetal 8 is returned to the initial position again as shown by a solid line to stop the flow- out of the oil in the tank 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixing device for a copying machine, and particularly to an oil application device thereof. - In order to prevent the so-called offset phenomenon in which a part of the toner adheres to the roller surface when the copy paper carrying the toner image passes between a pair of rollers that are in pressure contact with each other and is fixed, It has been widely practiced to apply an appropriate amount of anti-offset agent such as silicone oil to the surface of the roller that comes into contact with the roller.

A typical example of this divine oil application means is known, for example, as shown in FIG. 1A. That is, it is equipped with a fixing roller 1 and a pressure roller 2 that is in pressure contact with the fixing roller 1, and the copy paper P carrying the toner image is passed between these rollers to perform fixing. Then, the applicator roller 3 is brought into contact with the fixing roller 1, and the silicone oil is stored in a container 4 placed at an appropriate location in the first copying machine.
The felt 5, which is partially immersed in the oil, is brought into contact with the application roller 3 with a substantially constant force, and using capillary breakage,
The oil in the container is configured to be supplied to the fixing roller 1 via the felt 4 and the application roller 5.

In such a coating means, when the oil on the surface of the fixing roller 21 becomes insufficient and the frictional force between the roller 1 and the roller 6 increases, the coating roller 3 rotates and the oil is applied to the fixing roller 1.
If the amount of oil on the surface of the fixing roller 1 becomes too large, the applicator roller 3 will not follow the fixing roller 1, and the oil supply will be stopped.In this way, a small amount of oil will always be supplied to the fixing roller 1. It is supposed to be done. This type of device uses the frictional force between the fixing roller and the applicator roller, and the change in the frictional force between the applicator roller and the felt. Even though the oil in the portion of the roller corresponding to the copy paper in the middle is consumed, there is no change in the relationship between the two frictional forces described above, and as a result, the applicator roller 6 rotates at its fullest, so the fixing roller 1 The disadvantage of deteriorating the image quality of copies due to insufficient oil supply to the printer was avoided.

In order to eliminate these shortcomings, efforts were already made in JP-A-53-
Oil application means as shown in Japanese Patent Application Laid-open No. 119053 and Japanese Patent Laid-Open No. 53-68240 have been proposed. FIG. 1B discloses the one disclosed in the former publication, in which a bow 31, reference numeral 3, is attached to two shafts relative to the fixing roller 1.
Two application rollers as shown in 2.36 are provided, and each shaft can rotate independently. Therefore, for example, if a fixing process is performed on copy paper with a width equivalent to that of the applicator roller 31, only the applicator roller 31 will supply oil a full number of times as the oil is consumed. 1) As mentioned in 1■, inconveniences are likely to occur. Figure 1C discloses an oil application device listed in the Ministry's gazette after +iif, which includes a fixing roller 1, an application roller 6,
Container 4 for storing oil, felt 5 for guiding oil
etc. are basically different from those shown in FIG. - 1 to 2 are divided into a plurality of parts (1" is divided into 2 parts), at least one of which is connected to the plunger 6, and a felt is connected to this by controlling the plunger 6. - Apply IXlf so that it can be pulled off the IJ roller, and then connect the oil supply 1111.
The x-circle is constructed to fit inside copy paper.

However, in the case of the well-known oil applicator described above, in which oil is constantly supplied to the fixing roller side basically by utilizing capillary phenomenon, the oil is caused by the surface condition of the valley roller and the temperature and humidity. Due to changes in the properties of oil, it has been extremely difficult to constantly apply pre-optimized oil to predetermined locations. Furthermore, if the fixing device is left in a stopped state for a long period of time, there is a risk that the applied oil will flow down from the applying roller to the fixing roller and stain the copy at the beginning of the next operation. This method has a complicated structure and requires extra space within the copying machine, which poses problems in terms of cost and maintenance.

This invention has been made in view of the shortcomings of the known oil applicators as outlined above, and includes a bimetallic box or oil control member disposed in or near the oil tank to heat it. The system is configured so that the oil in the tank is constantly supplied to the fixing roller with a cold illumination, and the supply of oil to the roller is cut off in case of anxiety. (11) The oil supply opening means 1 is extremely compact as a whole, and the limited space inside the copying machine is not particularly required for the control means 11. It provides:

Preferred embodiments of the present invention will be described below with reference to drawings of removed material.

FIG. 2 is a side view showing one embodiment of the present invention, in which a fixing roller 1
and application roller 2 rotate in pressure contact with each other, and l
・The copy paper P carrying the Na image is running! It is assumed that the toner image is fixed to the copy paper during the printing process. The toner image is on the side of the fusing roller 1 on the surface of the copying paper, and an oil tank 4 containing an anti-offset agent such as silicone oil is attached to the copying machine at a suitable location above the fusing roller.
is arranged.

A hollow protrusion 41 is formed at the bottom of the oil tank 4, extending over almost the entire length of the fixing roller, and having an open lower end. be. The tip of the oil application member 7 is pressed against the surface of the foot checking roller 1, and the oil in the tank 4 is supplied to the surface of the first fixing roller by capillary action and/or N force.

A free end of a bimetallic material 8, one end of which is fixed to the bottom of the tank, is attached to the upper end opening of the hollow protrusion 41 holding the application member 7 so as to cover the entire length of the opening. Furthermore, a heater 9 for heating the bimetal and the oil in the tank is arranged near the free end of the bimetal. It is assumed that the bimetal 8 normally has its upper opening closed, as shown by the solid line in FIG. 2, to prevent the oil in the tank from flowing down and escaping within the hollow protrusion. 1 (After the copying machine starts feeding paper, the heater is energized at an appropriate timing, taking into consideration the characteristics of the bimetal, the heating conditions of the heater, etc., and this causes the bimetal 8 and the oil in the tank to
In particular, the bimetal 8 is heated by the heater, which is located near the bimetal.

Indicated by the broken line in Figure 2-4-, 1: Hollow protrusion 41 deformed into a sea urchin
The two open ends 11 of the fixing roller 1 are opened, and the oil flows down and is applied to the surface of the fixing roller 1 by blowing the application section AA7. Since the oil is also heated like this lip, l'lfl'), the oil near the bimetal has a ηL mobility of 1, so even a slight deformation of the bimetal can easily remove it from the tank. This is convenient because it tends to flow out.

When the communication line 11L to the heater 9 is stopped, the bimetal is again placed at the 111th position as shown by the solid line in FIG. 2 to prevent oil from flowing out of the tank.

It is obvious that the flow of oil flowing out can be controlled by appropriately controlling the energization time and current.

The oil application device of the 1ν copying fixing device a according to the present invention is as follows:
Since the oil tank supplies oil from the oil tank to the fixing roller, it is equipped with a bimetal that opens and closes the aging section according to temperature changes, so oil may be unnecessarily supplied to the fixing roller when the fixing device is not in use. Since the oil is reliably blocked without any oil leakage, the above-mentioned drawbacks of the known coating devices can be solved.

FIG. 3 shows another embodiment of the present invention. In this embodiment, an oil tank 4 is disposed above the foot care roller, and the oil in the tank is applied via an applicator 7. The configuration for supplying the fixing roller to the fixing roller is the same as that shown in FIG. It is separated into .82, and the valley bimetal part 81.8
The heater 9 for opening and closing the heater 2 is also separated into heater parts 91 and 92, and each heater part can be energized or deenergized separately. Therefore, the bimetal part 81
．． 82 also operates separately to supply oil to the multilayer rollers. In addition, when the bimetal part is formed separately in this way, the inside of the hollow protrusion and the application member are also made of bimetal 'f.
It is best to divide the fixing roller according to the dimensions of A81.82 and configure it so that oil is not supplied to the surface of the fixing roller corresponding to the unused bimetal part.

By separating the bimetal parts into a plurality of parts (two in the case of the embodiment shown in FIG. 3) and configuring each part to be able to operate independently, it is possible to make copies of several copies of different sheets of paper. Accordingly, oil can be effectively supplied only to a desired surface portion of the fixing roller.

FIG. 4 shows an embodiment in which a flexible planar heating element 93 is adhered to the bimetal 8 that acts as a valve in the embodiment shown in FIG. This can be done quickly, and the responsiveness of the valve action of the bimetal to the energization of the heat generating member can be improved.

FIG. 5 shows still another embodiment of the present invention.

The bimetal 8 is attached to a portion of the hollow protrusion 41 that guides oil from the oil tank 4 to the fixing roller 1 where the applicator 7 is not present. In this case, the bimetal 8 has one end edge attached to one of the inner walls of the hollow protrusion 41, and the other end edge -10- is in pressure contact with the opposing inner wall surface, so that the oil in the tank 4 tends to flow out at all times. It's like that. An appropriate heat source such as a heater 9 or a planar heating element is arranged near the bimetal, and when it is energized, the free end wire of the bimetal 80 rotates clockwise in the figure, opening the oil flow passage, and the energization is stopped. Then the bimetal returns to the position shown and the oil is shut off.

With this configuration, as mentioned in the case of the previous embodiment, when the heater etc. is energized, the oil itself is heated, increasing its fluidity and substantially increasing the sensitivity of the bimetallic valve. However, in the case of this embodiment, the amount of oil present in the area where the heater etc. is present is effectively small, so the temperature rises rapidly and the rate of increase in fluidity becomes large. 2 can be achieved by substantially further improving the valve function.

FIG. 6 shows a further embodiment of the present invention, in which the applicator member 7 does not have a hollow protrusion protruding from the tank 4 as shown in the previous embodiment.
is arranged to extend from the top of the tank to near the fixing roller 1. An appropriate heating source such as a heater 9 or a planar heating element 93 indicated by the neck line 1 is provided near the bimetal 8 on which the coating member 7 is placed.

The applicator member 7 is normally separated from the surface of the fixing roller 1 as shown in the figure, and when the heating source is energized, the bimetal 8 and therefore the applicator member 7 in contact with it rotate in the direction of arrow A to perform fixing. Oil can be supplied to the rollers.

With this configuration, the oil in the tank is guided in the +1♂1 direction without being guided downwards in the tank as in the above-mentioned implementation 1911, so the height of the fixing device as a whole can be reduced. Therefore, depending on the space within the copying machine, this can be used more effectively.

As explained above, in the present invention, when supplying oil to the fixing roller from an oil tank containing oil for preventing offset phenomenon, a bimetal is placed in the middle between the two, and the oil is not always supplied to the fixing roller. The bimetal is completely disconnected, and when necessary, the bimetal is heated and deformed to operatively connect the inside of the tank and the fixing roller to supply oil to the roller, which reduces the flow of oil itself that occurs as the bimetal heats up. Coupled with the increased performance, it is possible to supply just enough oil to the fixing roller.
Even if the fixing device is stopped for a long time, excess oil will not leak out and contaminate the copying machine and copies.

By dividing the bimetal extending in the axial direction of the fixing roller into several bales and configuring them to operate separately, the necessary portions of the fixing roller surface can be applied to multiple types of copy paper with different paper contents. Oil can only be effectively supplied to

Furthermore, the oil applicator according to the present invention is extremely compact as a whole, since its main components such as bimetals and heating sources such as heaters can be placed in or near the oil tank, and no additional equipment is required. Since the cost is low, the limited space inside the copying machine can be used effectively.

-16-

[Brief explanation of the drawing]

FIG. 1 A11 (and C are side views, plan views, and oblique views showing an oil coating device of a known copying machine fixing device, FIG. 2 is a cross-sectional view showing an embodiment of the present invention, and FIG. 6 is a A perspective view showing an embodiment of 411! of the present invention, FIG. 4, FIG. 5, and FIG. 6 each show still other embodiments of the present invention.
ll! I is a sectional view. DESCRIPTION OF SYMBOLS 1... Fixing roller, 2... Pressure roller, 3... Application roller, 4... Oil tank, 5.7... Application member, 8... Bimetal, 9... Heater, 96...
Planar heating element-14-

Claims (1)

[Scope of Claims] A fixing roller and a pressure roller that is in pressure contact with the fixing roller are provided, and a copy sheet bearing a toner image is passed between these rollers and fixed, and a separate offset roller is installed on the surface of the fixing roller. In an oil applicator that sequentially supplies oil from an oil tank containing oil for preventing phenomena, a heat source is disposed between the oil tank and the fixing roller to heat and deform the valve that opens and closes depending on the temperature. The fixing device of a copying machine is configured such that the valve always shuts off between the oil tank and the fixing roller, and by operating a heating source, the two are communicated with each other to supply the oil in the tank to the fixing roller. Oil applicator.