JP3128668B2 - Fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for an electrophotographic recording apparatus.

In recent years, with the generalization of computers and word processors, many electrophotographic recording apparatuses such as copying machines, laser printers, and facsimile machines have been used. As a fixing device of these recording devices, a fixing device which has a heat fixing roller having a built-in heat roller and a pressure roller which presses against the heat roller, and supplies a recording medium having an unfixed toner image between the two rollers to perform fixing. Is widely used.

[0003]

2. Description of the Related Art FIG. 6 is a side view showing an outline of a conventional fixing device of this type. In FIG.
Is a pressure roller which is in pressure contact with the heat fixing roller 1, 4a and 4b are roller cleaners for removing toner and dust adhering to each roller, 5 is a thermocouple, 6 is always applying uniform oil to the surface of the heat fixing roller. An oil application mechanism 7 is provided for separating the recording medium from the heat-fixing roller 1, and 8 is a guide for guiding the recording medium 100 between the rollers.

Reference numeral 9 denotes a guide for guiding the fixed recording medium to the outside, 10 denotes a heating heat source built in the heat fixing roller 1, 11 denotes a side plate of a fixing device, and 12 denotes an unfixed toner image. The heat fixing roller 1 is made of an aluminum tube 2a.
Is lined with silicone rubber 2b. The operation of the fixing device having such a configuration is as follows.

[0005] The recording medium 100 to which the toner image on the surface of the photosensitive drum (not shown) is transferred is conveyed from the right side in the figure. In the fixing device, the heat fixing roller 1 is heated by a heat source 10 for heating.
, And this is detected by a thermocouple 5 and the surface temperature of the heat fixing roller 1 is kept constant through a controller (not shown). When it is detected that the roller surface has reached a desired temperature, the recording medium 100 having the unfixed toner image 12 is passed between the heat fixing roller 1 and the pressure roller 3.

At this time, the toner on the recording medium 100 is
The toner is melted by heating by the heat fixing roller 1 and pressurized by the pressure roller 3, and is fixed and solidified by a decrease in temperature after passing between the two rollers. However, the surface of the heat fixing roller 1 is lined with silicone rubber 2 b. As a result, the surface of the toner image after passing between the rollers becomes smooth, and an image having a good color reproduction range with good brightness and saturation can be obtained.

In the fixing device described above, since there is a possibility that toner remains on the surface of the heat fixing roller (offset) without being fixed on the recording medium, the surface of the heat fixing roller may be made of silicone oil or the like. It has been practiced to apply an anti-offset agent. The oil application mechanism 6 is provided for this purpose. As shown in FIG. 7, an anti-offset agent is stored in a container 14, and a surface-treated metal roller 13 is immersed in the anti-offset agent and rotated. By doing so, the anti-offset agent is scraped up.

At the same time as the anti-offset agent is scraped up, the anti-offset agent is regulated to a fixed amount determined by the surface shape of the metal roller 13 and the viscosity of the anti-offset agent, and is made uniform on the surface of the metal roller 13. Next, the uniformized anti-offset agent is supplied to an anti-offset agent applying roller 15 which is formed by winding felt or silicone rubber having an anti-offset agent impregnating and retaining characteristic around a shaft to form a roller.
Finally, it is applied to the surface of the heat fixing roller 1.

FIG. 8 shows another conventional oil application mechanism.
In this oil application mechanism, one end of a replenishing member 16 such as felt or artificial leather having an anti-offset agent impregnating property is immersed in a container 17 containing an anti-offset agent, and the offset transmitted through the replenishing member 16 by a capillary phenomenon. The preventive agent is applied by bringing the other end of the replenishing member 16 into contact with the heat fixing roller 1. Reference numeral 18 denotes a scraping member for scraping off the excessively applied offset preventing agent and returning it to the container 17.

FIG. 9 shows another conventional oil application mechanism.
This mechanism is disclosed in Japanese Patent Laid-Open No. 23382/1990, and is provided with an anti-offset agent supply pipe 1 having a hollow inside.
9 is filled with an anti-offset agent, and the anti-offset agent is oozed through a fine hole (not shown) in the wall surface of the anti-offset agent supply pipe 19, and then the anti-offset agent such as felt or artificial leather wound around the shaft surface. The agent application member 20 is impregnated and applied.

However, this alone limits the amount of the incorporated offset preventing agent. Offset prevention agent supply mechanism 2
Numeral 1 is provided to solve this problem, and supplies an offset preventing agent into the offset preventing agent supply pipe 19 from outside.

[0012]

In the conventional anti-offset agent application mechanism shown in FIGS. 7 and 8, the container for storing the anti-offset agent is in an open state, and the apparatus is tilted during transportation or the like. If there is, there is a possibility that the anti-offset agent may leak to the outside, so that care must be taken during maintenance. In addition, the mechanism is complicated and the number of parts is increased, so that the cost is increased. In addition, the space for the offset preventing agent applying mechanism is increased, which hinders downsizing of the apparatus.

The mechanism shown in FIG. 9 can be said to be a solution to these problems in terms of the method of storing the offset preventing agent and the reduction in cost and size. However, in this mechanism, at one end of the anti-offset agent supply pipe 19, the supply amount of the anti-offset agent stored in the supply pipe is regulated by the chicken feed valve mechanism 22 so that the liquid level of the anti-offset agent is constant. Therefore, when the entire device is tilted so that the supply amount regulating portion is lower, a situation occurs in which the offset preventing agent is not supplied at the other end. Further, this situation becomes remarkable in the case of a fixing device having a large sheet width.

The supply of the anti-offset agent from the anti-offset agent storage tank 23 of the anti-offset agent supply mechanism 21 to the anti-offset agent supply pipe 19 is performed by gravity, so that the storage tank 23 is always above the supply pipe 19. It must be arranged, and furthermore, since the arrangement is limited to the end of the supply pipe 19 due to simplification of the configuration, the degree of freedom in design is reduced.

An object of the present invention is to provide a fixing device having a simple structure capable of stably supplying an offset preventing agent to the entire position corresponding to the sheet width.

[0016]

In order to achieve the above object, according to the present invention, a heat fixing roller and a recording medium on which an unfixed toner image is formed and conveyed are pressed against the heat fixing roller to perform fixing. And a pressure roller for performing the fixing operation, wherein the offset preventing agent is accommodated inside, and is pressed against and driven by the heat fixing roller, and the offset preventing agent oozing out from the inside to the outside is applied to the surface of the heat fixing roller. and offset preventing agent applicator roller for applying, the offset preventing agent coating the offset preventing agent to the offset preventing agent coating the roller
It is transported from outside by the operation using the rotational force of the roller as power ,
And configuration, characterized in that the offset preventing agent transport supplying means consisting supply tube pump, an offset preventing agent coating mechanism of closed structure with an integrated provided.

[0017]

[0018]

[0019]

The anti-offset agent is supplied from the outside into the anti-offset application roller by the anti-offset agent transporting means of the anti-offset agent application mechanism, and oozes out from the inside of the application roller. The anti-offset agent applying roller rotates while being pressed against the heat fixing roller, and the anti-offset agent is applied to the surface of the heat fixing roller.

The anti-offset agent applying mechanism having such a configuration and operation has a closed structure, and the anti-offset agent is conveyed into the anti-offset application roller from an external anti-offset storage tank or the like. Since the sheet is conveyed and supplied by the supply means, the offset preventing agent is always stably present in the offset applying agent applying roller. Therefore, it is possible to solve the conventional problems that the offset preventing agent is not supplied or the offset preventing agent leaks outside due to the inclination of the device.

Also, since the arrangement of the tank for storing the offset preventing agent can be made freely, it is possible to reduce the size of the apparatus.

[0022] Also, the transport of the offset preventing agent requires no special driving source for the supply, is simple and compact structure.

[0023] Also, it is possible to avoid the metal powder in question contamination of impurities caused by the friction of the drive unit mechanism portion in offset inhibitor.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

[0025]

FIG. 1 is a front view showing the structure of the main part (around the heat fixing roller) of the fixing device of this embodiment. In the figure, reference numeral 31 denotes a heat fixing roller, and 32 denotes an offset preventing agent applying mechanism (hereinafter abbreviated as an applying mechanism). It is. The application mechanism 32 includes an anti-offset agent application roller (hereinafter abbreviated as an application roller) 33 and an anti-offset agent transport / supply unit (hereinafter abbreviated as a supply unit) 34. Except for the application mechanism 32, the configuration is substantially the same as that of the conventional FIG. These are not shown.

The heat fixing roller 31 is formed by lining silicon rubber on the surface of a raw aluminum tube as in the prior art.
Further, the rubber surface is made of an insulating or dielectric tube (50
μm thick Teflon tube).
A rotating gear 36 made of a heat-resistant resin is fixed to a shaft 35 at one end of the heat fixing roller 31, and a shaft 35 at the other end is fixed to a shaft 35 at the other end.
A sleeve 37 made of a heat-resistant resin is fixed. The rotating gear 36 and the sleeve 37 are supported by a fixing device side plate 39 of the apparatus via a bearing 38, and the heat fixing roller 31 is driven by a driving system (not shown) via the rotating gear 36 to rotate. Reference numeral 40 denotes a heater (heat source) for heating the heat fixing roller 31. The thermocouple for controlling the surface temperature of the heat fixing roller 31 is not shown.

The application roller 33 of the application mechanism 32 has a configuration in which an anti-offset applying member (hereinafter abbreviated as an application member) 42 made of silicon rubber, felt, artificial leather, or the like is concentrically wound around a hollow roller shaft 41. The application member 42 is in pressure contact with the heat fixing roller 31.
For example, when metal is used as the material, the roller shaft 41 has fine holes 41a that allow the anti-offset agent to pass through the entire application width, and the anti-offset agent inside the shaft oozes out to the application member 42 from here. Are supplied.

The supply means 34 of the coating mechanism 32 includes a tube pump 43 attached to the left end of the roller shaft 41.
And an anti-offset transfer tube (hereinafter abbreviated as a transfer tube) 44 formed of an oil-resistant elastic body. As shown in detail in FIG. 2, a rotor (drive unit) 45 of the tube pump 43 has a rotatable roller 4 at its distal end.
6 is provided. The transport tube 44 is fixed at the pump portion so as to draw an arc on the circumference of the rotor 45, and one end is located at the left end of the roller shaft 41, and the other end is located at an offset preventing agent storage tank (hereinafter abbreviated as storage tank). Connected. The right end of the roller shaft 41 is connected to the storage tank via a tube 47 made of the same material as the transport tube 44.

Accordingly, when the heat fixing roller 31 rotates, the rotor 45 rotates together with the rotation of the coating member 42 which is pressed against the heat fixing roller 31 to move the anti-offset agent in the transport tube 44 so as to be squeezed out. Then, the sheet is conveyed and supplied into the roller shaft 41. In the roller shaft 41, as described above, the offset preventing agent oozes out from the fine holes 41a and is supplied to the application member 42, and is supplied to the heat fixing roller 31 to which the application member 42 is pressed.
Most of the remaining anti-offset agent enters the storage tank through the tube 47 and then returns to the supply means 34.
The transfer force of the offset preventing agent can be adjusted by changing the tube diameter of the pump portion and the number of rotors.

As described above, by providing the supply means 34, the anti-offset agent can always be stably present in the roller shaft 41. Since the anti-offset agent is biased due to the inclination of the conventional device, the surface of the surface of the roller is prevented. The problem of no supply to the offset preventing agent applying member is solved.
Further, as described above, one end of the roller shaft 41 is connected to the storage tank via the tube pump 43, and the other end is connected to the storage tank via the tube 47, so that the anti-offset agent has a sealed structure. It is possible to prevent the offset preventing agent from leaking to the outside during tilting, maintenance of the apparatus, and movement of the apparatus. Furthermore, since the storage tank can be arranged freely,
It is possible to reduce the size of the device configuration.

When the above-described tube pump system is used as the supply means, the driving portion is omitted, and it is possible to prevent impurities such as metal powder generated by abrasion of the mechanism from being mixed into the offset preventing agent. it can. Moreover, the mechanism is simplified.

In the case of this embodiment, it is desirable that the arrangement of the storage tank is higher than the coating member 42 in order to use up the offset preventing agent in the storage tank. However, the conveying force of the offset preventing agent, which is determined by the tube diameter, the number of rotors, the viscosity of the offset preventing agent, and the like at the pump portion, is larger than the resistance force due to the viscous resistance passing through the tube, the force caused by the natural fall of the offset preventing agent, and the like. If the container is not transported, the degree of freedom in designing the storage tank is limited.

When silicon oil is used as the offset preventing agent, 100 to 100
A material having a viscosity of about 10,000 cementum Stokes can be used.

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

As described above, according to the present invention, the following various excellent effects can be obtained. (1) Applying an offset preventing agent to the heat fixing roller
Since the operation is performed by one offset prevention agent application roller that is in pressure contact with the heat fixing roller, the size of the offset prevention agent application mechanism can be reduced. (2) The anti-offset agent applying mechanism has a closed structure, and can be used for a long time because the anti-offset agent is supplied to the inside of the anti-offset agent applying roller from the outside by the anti-offset agent conveying / supplying means. Also,
Due to the inclination of the device, neither the anti-offset agent is supplied nor the anti-offset agent leaks to the outside. (3) By using the power of the drive unit as the rotational force of the anti-offset applying roller, a special driving source for conveying and supplying the anti-offset agent can be omitted, and the structure is simple and small. (4) When a rotor or the like as shown in FIG. 2 is used as the driving unit, the driving unit can be prevented from touching the anti-offset agent, and impurities such as metal powder generated by abrasion in the mechanism of the driving unit can be reduced. It is possible to avoid mixing in the anti-offset agent.

[Brief description of the drawings]

1 is a front view showing the main structure of the fixing device of the actual施例of the present invention.

FIG. 2 is an operation explanatory view of a main part of FIG. 1;

FIG. 3 is a side view showing an outline of a conventional fixing device.

FIG. 4 is a detailed view of a main part of FIG . 3;

FIG. 5 is a side view showing another conventional oil application mechanism.
You.

FIG. 6 is a front view showing another conventional oil application mechanism.
You.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 31 Thermal fixing roller 32 Anti-offset agent application mechanism 33 Anti-offset agent application roller 34 Anti-offset agent transport / supply means 44 Offset prevention agent transport tube 45 Rotor (drive unit)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-62572 (JP, A) JP-A-59-186862 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (1)

(57) [Claims] 1. A fixing device comprising: a heat fixing roller; and a pressure roller for pressing a recording medium on which an unfixed toner image is formed and conveyed to the heat fixing roller to perform fixing. An anti-offset applying roller for applying an anti-offset to the surface of the heat-fixing roller, the anti-offset applying roller being press-contacted and driven by the heat-fixing roller while accommodating the anti-offset agent, and the anti-offset-agent applying roller The anti-offset agent is supplied into the rotation of the anti-offset application roller.
The rolling force fed from the outside by the operation that the power supply switch
A fixing device, comprising: an anti-offset agent applying mechanism having a hermetically sealed structure in which an anti-offset agent conveying / supplying means comprising a tube pump is integrated.