JPH07160141A - Fixing device - Google Patents

Abstract

(57) [Abstract] [Purpose] Even if an unexpected situation such as tilting or tipping occurs when the fixing unit is installed in or removed from the main body, the leakage of oil from the fixing unit is prevented. [Structure] The oil stored in an oil tank 18 is supplied to an oil collecting plate 14 by an oil pump 16 and applied to a fixing roller 1 via an oil applying roller 12. The recording material is conveyed between the fixing roller 1 and the pressure roller 2 in the arrow direction and fixed. The oil attached to the pressure roller 2 is cleaned by the cleaning blade 5 together with the paper powder and the toner.
Scraped off by the oil absorber 10 in the oil pan 6
Is absorbed by. At least the oil pan 6 of the waste oil recovery container and the oil tank 18 of the oil container can be simultaneously replaced.

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 color or monochrome of an electrophotographic apparatus.

[0002]

2. Description of the Related Art Conventionally, electrophotographic color copying machines have been actively commercialized, and in recent years, they have also been applied to color printers and the like.

In a fixing device of a color copying machine, it is necessary to uniformly and stably heat both the toner and the recording material to sufficiently dissolve and mix thick toner images of multi-color superposition, and the fixing roller. It was necessary to provide a heater inside both the pressure roller and the pressure roller and use a roller having a large heat capacity. In addition, a thick rubber layer is required to have a multi-layered toner unevenness wrapping effect.
Further, it has been performed that a roller is provided in a multi-layer in order to have a release agent and prevent oil swelling.

Not only the color copying machine as described above, but also the electrophotographic copying machine, printer, etc.,
Conventionally, a heat fixing method in which a recording material having an unfixed toner image is passed between a pair of heated and pressurized rollers to fix the toner is widely used, but one of the problems of the heat fixing method The occurrence of an offset phenomenon, in which the molten toner on the recording material adheres to the roller, can be mentioned. conventionally,
As a countermeasure against this, a heat-resistant releasing layer such as silicone rubber or fluororesin is provided on the surface of the roller, and a releasing agent such as silicone oil is applied. However,
Nevertheless, offset toner was gradually accumulated on the surface layer of the roller, resulting in deterioration of the roller and shortened life.

Therefore, a method has been proposed in which a cleaning member such as a fibrous web pad is brought into sliding contact with the roller surface and cleaning is performed by forced friction to remove the toner from the roller surface. The rollers, silicone oil, cleaning members, etc. are usually replaced or maintained once or several times as consumable members by a service person or user during the life of the main body machine of the image forming apparatus.

Further, in the above-mentioned conventional apparatus having a cleaning member for the web and the pad, the oil applying mechanism,
These have hindered the miniaturization of the device because a cleaning mechanism is required. Furthermore, the replacement of rollers, oil, cleaning materials, and maintenance are not preferable from the viewpoint of safety and hygiene for the user side, and there is also the problem that maintenance costs will increase if the manufacturer side performs service. . In the monochrome / two-color type fixing device, the above problem is currently being solved to some extent, but in the color fixing device, it still remains as an essential problem. One of the reasons is that a color image needs to be fixed with a thick toner layer of multiple colors such as yellow, cyan, magenta, and black.
Output that is close to a solid image is almost always required, and the endurance load is remarkably large compared to monochromatic and two-color images. Further, since the color developing property and the color mixing property cannot be enhanced unless they are completely melted and mixed, a toner resin used is a material having a small viscoelasticity that melts sharply at a relatively low temperature. This resin has a much worse release agent for the roller than for monochrome.

Therefore, in order to maintain the releasability even in a roller having a silicone rubber / fluorine resin surface, the surface is always covered with a silicone oil having a relatively low viscosity (about several hundreds cs), and the releasing effect is obtained. Therefore, it is necessary to prevent the offset phenomenon and the deterioration of the roller. that time,
There is a demand that the amount of oil used should be kept as small as possible, the time and labor required for replacement should be reduced, the large-capacity oil tank should be downsized, and the coating mechanism should be simple.

[0008]

However, in the above-mentioned conventional example, since oil application is essential, various problems arise. For example, since the life of the fixing roller for color is currently ⅔ to half or less of the life of the main body, it is necessary to replace the roller once or several times during the life of the main body.
It is not desirable in terms of hygiene and safety to let the user directly handle the roller to which oil is attached, and it is beyond the scope of user maintenance.
On the other hand, desktop type color leather printers, which are expected to appear in the market at present, are difficult to meet with service personnel in terms of quantity, running cost and system.
Handling should be user-friendly.

Therefore, the present inventors decided to use a simple and lightweight fixing device as a printer so as to match the roller life with the fixing device life and replace the unit as a unit.

The next problem was the relationship between the oil application section for applying oil to the fixing roller, the lower oil pan for receiving oil drip, and the fixing unit. If the former two units are provided on the main body side and can be separated from the fixing unit, it is good for downsizing and weight saving of the unit itself, but it is preferable that the coating unit itself be stuffy at the fitting part at the time of separation. Instead, oil spills can cause oil pollution inside and outside the aircraft. Therefore, the inventors of the present invention have a configuration in which the former two are incorporated and integrated in the fixing unit. At least the main body itself does not have any mechanism related to oil, and the policy is to handle the oil inside the fixing unit. However, because of this, when the fixing unit is detached or replaced by the user, there is a possibility of oil leaking out due to tilting or tipping over of the unit. It was decided.

[0011]

Therefore, in the present invention, the oil replenishment portion is a closed system except for exposing only the oil thin layer coating portion, which is the minimum required for oil coating, inside the unit, and is required for the oil coating portion. Only a small amount was replenished. Furthermore, the waste oil that drips to the bottom is forcibly scraped by a blade and immediately absorbed by an oil absorber such as a fiber material to be treated, thereby preventing the risk of oil leakage due to the inclination and tipping of the unit described above. It is a thing.

[0012]

Embodiment 1 Embodiment 1 of the present invention will be described with reference to the drawings.

First, a first embodiment of the present invention will be described with reference to FIG. In FIG. 1, reference numeral 1 is a fixing roller, and a pressure roller 2 is pressed against the fixing roller 1 to form a nip portion between the fixing roller 1 and the fixing roller 1, so that the fixing roller 1 is driven to rotate. The fixing roller 1 is in the form of a hollow cylinder, and a halogen heater 3 is built in the hollow space to supply heat required for fixing. The pressure roller 2 is heated by the halogen heater 3 '. To control the temperature of the roller, the thermistor 4 as a temperature detecting element or the thermistor 4'as the pressure roller 2 is placed in contact with the paper non-passage area of the fixing roller 1 and the surface temperature of the roller is changed by the resistance value change according to the detected temperature. Is detected and the current control of the halogen heaters 3 and 3'is performed by the control device (not shown) so that the roller surface temperature becomes a predetermined value.

An oil applying roller 12 is disposed in contact with the surface of the fixing roller 1, and oil is applied by the contact applying rotation of the oil applying roller 12. At the time of fixing, the contact is made to apply and at the time of non-fixing, the contact is made to prevent oil dripping.

In the apparatus of this embodiment as described above, the unfixed recording material is guided by the guide 8 and enters the nip portion from the right side, and is pressed and heated by the surface of the fixing roller 1 on which the uniform oil layer is formed. After receiving and fixing, guide 8 '
Will be guided to and ejected. The surface of the fixing roller 1 that has been fixed is rubbed against the cleaning web 7 again during rotation, and the offset toner is removed and oil is applied at the same time. Reference numeral 9 is a separation claw for fixing the recording material and the pressure roller 2.

The fixing roller 1 has a structure in which an elastic layer of several tens of μm or more is provided on the core shaft of aluminum or the like in order to follow the thickness (several to several tens of μm) of the multicolor toner of a color image of four to four colors. is necessary. If the elasticity is low, unfixed portions of the toner may not be fixed or the toner may be crushed, resulting in a decrease in resolution. The material of the elastic layer is preferably a phenyl- or dimethyl-based liquid silicone rubber RTV or LTV type because it has elasticity. In particular, RTV has a high affinity with silicone oil and is easy to apply oil. good. The above-mentioned RTV or LTV may be used as the surface layer, and a heat-resistant HTV layer may be provided below the surface layer to form a multilayer structure in which heat deterioration and peeling of the back surface of the surface layer are prevented.

Since the pressure roller 2 may have a smaller elasticity than the fixing roller 1, the pressure roller 2 can be simplified, and a layer of HTV, fluororubber or the like may be provided on the aluminum core shaft, and PFA or PTFE may be provided on the surface. It may be coated to prevent oil swelling. RTV may be used.

Regarding the material of the oil, silicone oil is generally used at present, but dimethyl type is particularly used among them, for example, manufactured by Shin-Etsu Chemical Co., Ltd. KF-96 and the like are well known. Regarding the viscosity, those having a viscosity of tens of thousands cs or less can be used, but those having a viscosity of several thousand cs or less are preferable. Those having several tens of cs or less have high volatility, easily contaminate the charging wire in the machine, have a low flash point, and have a safety problem.

In the experiment based on this embodiment, the fixing roller surface layer is made of silicone rubber such as RTV, LTV, HTV, and the pressure roller surface material is made of RTV, HTV, LTV and other fluororubber, PFA, PTFE coated products. And The toner used is a sharp melt toner used in a color copying machine CLC-200 manufactured by Canon Sales Co., Ltd. The fixing temperature is 120 to 180 ° C. and the ripple is within ± 3 °, and the roller peripheral speed is 10 to 90 mm / s.
The range was ec. The oil used was KF-96 (described above) having a viscosity of 100 cs to 10000 cs.

As for the oil supply unit, an oil tank 18 which is a replaceable oil container is connected to the oil pump 16 via joints 17 and 17 'by a tube of silicone resin or the like. The structure of the oil tank 18 has oil contained in an aluminum pack in a rigid case. The structure of the joints 17 and 17 'is composed of a combination of rubber seals, springs, etc.
When 8 is detached, oil seals from both sides are made. The oil pump 16 has an oil replenishment nozzle 1 for applying oil.
Serves to send to 3. On the other hand, the type of pump in which the oil remaining in the application section is once collected in the oil tank 18 from the oil case 15 and reused is preferably a system in which the amount of oil is controlled by a pulse signal using an electromagnetic pump. In addition, it is inexpensive and good to use a gear pump. The pump should be equipped with a check valve. Since the oil supply unit is a completely closed system and there is no risk of leakage, it can be provided on the apparatus main body side or the fixing unit side.

As for the oil application section, the oil sent from the oil replenishing nozzle 13 is a plate for holding a minute amount of the replenished oil which is in close proximity or in close proximity to the oil application roller 12 having silicone rubber as the surface layer. 1
4, the oil is held between the oil applying roller 12 and the oil applying roller 12 only for a short period of time, and the oil applying blade 11 regulates the amount of oil as the oil applying roller 12 rotates. A homogeneous thin layer coating is made on top. The surplus oil drops from the plate 14 because of the oil, travels along the bottom surface of the oil case 15 and is recovered again by the oil pump 16. Therefore, only a very small amount of oil is always present in the oil case 15. Even when the unit itself tilts or falls when separated from the main body, oil leakage to the outside is almost prevented. Of course, the inclination caused by the movement of the main body when the main body is attached is not a problem.

The oil applied to the fixing roller 1 by the oil applying roller 12 is absorbed or adhered to the paper as the paper is passed and goes out of the machine.・ The oil applied during the subsequent rotation is
The cleaning blade 5 scrapes off the pressure roller 2 together with the paper dust and toner from the pressure roller 2 by transferring and adhering to the pressure roller 2, and drops below the cleaning blade 5 to form an oil pan 6 as a waste oil recovery container. Since the oil absorber 10 in the inside absorbs the oil promptly, there is no risk of oil leakage when the unit is tilted or overturned.

The material of the cleaning blade 5 is preferably made of fluororubber or the like, which has excellent releasability and close contact slidability. The material of the oil absorber 10 is preferably one that absorbs oil mainly by a capillary phenomenon of a natural or natural fiber body or a porous body. For example, it is preferable that fibers having a diameter of several to ten and several μm, such as polyester, polypropylene, and polyethylene, are laminated to have a thickness of several cm or less and processed into a non-woven fabric.
The surface may be subjected to a treatment for increasing lipophilicity. Among commercially available products, there are relatively inexpensive oil-dedicated absorbers such as "Wosep" (Toray) and "Powersorb" (3M). Another possible method is to solidify the oil by chemical change. Oil pan 6 with built-in oil absorber 10
Can be detached and replaced from the fixing unit.

In the experiment, the supply amount of the electromagnetic pump at the time of driving the fixing unit is set to a value of about 30 mg / sec, and the amount of application is always slightly larger than the actually required application amount so that oil breakage on the application roller does not occur. I did it. The actual amount of oil applied was about 15 mg in weight per area of A4 paper. The oil consumption of the oil tank is about 450c in capacity when 10,000 sheets of paper are passed.
c, the waste oil to the oil absorber is about 150cc,
The oil absorber could be a laminated non-woven fabric having a thickness of 10 mm. Therefore, the oil tank (500
cc capacity) and the oil pan (about 200 cc capacity) can be replaced at the same time to achieve good fixing over the unit life (about 50,000 to 100,000 sheets). The oil replacement timing is detected by the remaining amount detection sensor 19. The detection method may be a method that uses a floater (float), or a method that optically detects the presence or absence of oil in an oil path (path) by optical refraction. It is also possible to give a certain allowance to the capacity of the oil path and give advance notice of replacement. It is preferable to provide a backflow prevention valve 20 in a path for collecting waste oil and removing air so as to prevent oil leakage due to falling. A pump may be provided instead of the check valve.

As described above, "capacity of waste oil recovery container"
Is set in advance to a value that is less than the "oil container capacity" minus the "amount of oil that is absorbed by the paper up to the time of replacement and lost to the outside," so that the remaining amount of oil in the oil container is detected It is possible to replace the oil container and the waste oil recovery container at the same time because it notifies the replacement time and at the same time detects the fullness of the waste oil recovery container that contains the oil absorber or filter. Maintenance becomes simple. In addition, it is low cost because it is not necessary to fill the waste oil.

The structure of the second embodiment is shown in FIG. Figure 1 is an overview
The cleaning blade 5 and the oil pan 6 are integrated to perform the waste oil treatment and the blade replacement at the same time. In the current color fixing device, the cleaning performance of the blade is deteriorated when the durability is 10,000 sheets or more due to adhesion and accumulation of paper powder and toner and edge abrasion. There is an advantage that the blade replacement does not have to be performed separately from the waste oil replacement, and can be done only once.

The structure of the third embodiment is shown in FIG. The oil pan 6 has an oil absorber 10 made of a fibrous material or a sponge material that functions as a filter, and the filtered oil is subjected to a negative pressure by an oil pump 16 'to be collected in an oil tank 18 and then reused. Since the oil is viscous, it is necessary to apply a negative pressure to suck out the oil. With this configuration, the capacity of the oil pan 6 can be reduced, and the oil can be saved.

Example 4 is shown in FIG. The oil pan 6 and the oil tank 18 are integrated so that the user does not forget to replace the oil pan 6 only by replacing the oil tank 18.

In addition, in order to prevent the oil from overflowing from the oil pan 6 when the coating amount increases for some reason and exceeds the oil holding capacity of the oil absorber, FIG. It is advisable to provide a path through which oil is once drawn from the oil pan 6 by the oil pump 16 ′ and then returned to the check valve 20.

The structure in which an oil tank is provided under the recovery container or the oil absorber as in Examples 3, 4, and 5 is integrated and is compact, and excess oil in the circulation system or the recovery system is gravitated. The advantage is that the oil can be stably collected and held in the oil tank. In addition, if negative pressure is applied by an oil pump as a means for generating a vertical or horizontal oil flow for collecting excess oil from the oil absorber or filter in the collection container into the oil tank, oil permeation The oil can be collected more efficiently than by relying on the nature and natural fall. This is because the oil has viscosity and the oil absorber has a fluid impedance.

[0031]

As described above, the present invention is provided with an oil supply system that is a closed system from the oil tank to the oil application section, and a waste oil treatment system that immediately absorbs waste oil in the absorber. Therefore, even if an unexpected situation such as tilting or falling occurs when the fixing unit is installed in or removed from the main body, oil leakage from the fixing unit is prevented and oil contamination to the outside does not occur. Further, both the oil tank and the waste oil can be easily replaced without getting the user's hands dirty.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a second embodiment of the present invention.

FIG. 3 is a vertical sectional view of a third embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of Embodiment 4 of the present invention.

FIG. 5 is a vertical sectional view of a fifth embodiment of the present invention.

[Explanation of symbols]

1 ... Fixing roller 2 ... Pressure roller 3,3 '... Halogen heater 4,4' ... Thermistor 5 ... Cleaning blade 6 ... Oil pan 7 ... Cleaning web 8,8 '... Guide 9 ... Separating claw 10 ... Oil absorber 11 ... Oil application blade 12 ... Oil application roller 13 ... Oil supply nozzle 14 ... Oil plate 15 ... Oil case 16, 16 '...
Oil pump 17, 17 '... Joint 18 ... Oil tank 19 ... Remaining amount detection sensor 20 ... Backflow prevention valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Miyashiro 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Nobuaki Kaburaya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Takehiko Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. A fixing roller including a heat source, a pressure roller arranged so as to be in pressure contact with the fixing roller, and a temperature detection arranged so as to contact the surface of the fixing roller or the surface of the pressure roller. An element, temperature control means for maintaining the surface temperature of the fixing roller or the pressure roller at a predetermined temperature based on the temperature detected by the temperature detecting element, and a mold release member provided on the surface so as to contact the surface of the fixing roller. An oil applying means for applying oil as an agent is provided, and the unfixed state is obtained by sandwiching and conveying the recording material carrying a multicolor multi-layered or single color unfixed developer image at the pressure contact portion of the fixing roller and the pressure roller. In a fixing device for fixing a developer image on a recording material, an oil container, an oil supply means from the oil container to the oil applying means, the fixing roller and the pressure roller are provided. These oil removing means and waste oil processing means are provided, and an oil absorber or a filter as the waste oil processing means is built in the waste oil recovery container, and at least the waste oil recovery container and the oil container can be simultaneously replaced. Fixing, characterized in that the capacity of the waste oil recovery container is preset to be equal to or more than the capacity of the oil container minus the amount of oil absorbed by the paper up to the time of replacement and lost to the outside apparatus. 2. The fixing device according to claim 1, wherein the simultaneous replacement timing of the oil container and the waste oil recovery container is determined by detecting the remaining amount of oil in the oil container. 3. The fixing device according to claim 1, wherein the oil container is arranged below the waste oil recovery container, and both are integrated. 4. A fixing roller containing a heat source, a pressure roller arranged so as to be in pressure contact with the fixing roller, and a temperature detection arranged so as to contact the surface of the fixing roller or the surface of the pressure roller. An element, temperature control means for maintaining the surface temperature of the fixing roller or the pressure roller at a predetermined temperature based on the temperature detected by the temperature detecting element, and a mold release member provided on the surface so as to contact the surface of the fixing roller. An oil applying means for applying oil as an agent is provided, and the recording agent carrying a multicolor multi-layered or single color unfixed developer image is sandwiched and conveyed at the pressure contact portion between the fixing roller and the pressure roller, thereby undecided. In a fixing device for fixing a developer image on a recording material, an oil container, an oil supply means from the oil container to the oil applying means, the fixing roller and the pressure roller are provided. These oil removing means and waste oil processing means are provided, and an oil absorber or a filter as the waste oil processing means is built in the waste oil collecting container, and the waste oil collecting container or the oil container is freely detachable from the fixing device. A fixing device, which is replaceable, wherein excess oil in the waste oil recovery container is recovered again in the oil container through an oil absorber or a filter by negative pressure applying means.