JPS614089A - Roller for fixing device - Google Patents

Abstract

PURPOSE:To replace only a surface coating layer in a deterioration state and allow easy repair by providing a roller body and an elastic surface layer which is attachable to and detachable from the roller body axially. CONSTITUTION:A pressure roller 2 which clamps and convey normal paper where a toner image is formed together with a fixing roller 1 and performs fixation processing is pivotally supported on the fixing device rotatably, and the pressure roller is energized by a pressure applying means so that the pressure roller is pressed against the fixing roll durijg fixation. The pressure roller 2 is constituted by adhering the thick elastic material layer 22 to the outer peripheral surface of a metallic roller core 2 and forming the roll body. Then, a heat-resisting separation type coating 23 made of a thin tube type elastic body with heat resistance is mounted attachably to and detachably from the roller body.

Description

[Detailed description of the invention] The present invention relates to a roller for a fixing device of an image forming apparatus.

In particular, the present invention also relates to an elastic roller that is effective as a fixing roller that is often used in image forming apparatuses.

In general, the elastic layer and properties of rollers for fixing devices are limited depending on the application, so the selection range of materials that can be used is extremely small, resulting in many problems in manufacturing and use.

This roller for a fixing device is often used as a presser roller or a fixing roller in an image forming apparatus (for example, a printing machine, a copying machine, a facsimile machine, etc.).

In a fixing device of an image forming apparatus, an unfixed image formed on a recording material using a powder or liquid developer is heated, pressurized, or heated and pressurized, and therefore the material for the fixing roller is subject to significant limitations.

Furthermore, the surface of the fixing roller needs to have releasability so that objects to be fixed such as developer forming an unfixed image do not adhere thereto. However, since adhesion of the fixing object cannot be completely prevented, a cleaning member that cleans the surface of the fixing roller, a separation claw that separates the recording material, and the like are brought into contact with the surface. These contact members are used to rub the surface of the fixing roller.

This has caused problems such as scratches on the roller surface, performance deterioration, and staining of the recording material during fixing. Furthermore, in the case of a roller whose temperature is controlled such as a heat fixing roller, a contact type temperature sensing element is used.

Not only does this problem become more serious, but it also causes various problems due to poor fixing or abnormal temperature rise, or a decrease in the durability of the sensing element itself.

A fixing roller that has deteriorated in this way is replaced with a new fixing roller because if it is used any longer, it will cause problems in image formation.

Generally, the fixing roller has a large diameter in order to form a predetermined pressure contact area for fixing, and is expensive because it is formed using many processes and many materials. In addition, replacement is often required several times or even dozens of times during the life of the image forming apparatus main body, placing a heavy burden on the user.However, when a deteriorated fixing roller Although only a portion of the surface of the roller has deteriorated, the roller itself is a fixed and integral type, so the entire roller must be replaced.

Therefore, not only is the cost of materials required for replacement extremely high, but it is also a waste of resources.

In order to solve this problem, the surface of the fixing roller was
t-rl! if:□Oh, 0-Yes6ゎ,,3,. - Fluctuations occur in the radius, resulting in changes in fixing properties, making it unsuitable for practical use.

The present invention has been made in view of the above-mentioned conventional drawbacks, and it is an object of the present invention to save materials, costs, etc. in replacing the fixing device roller, and to stably maintain the conditions required for the fixing device roller. Furthermore, it is an object of the present invention to widen the selection range of materials that satisfy the physical properties required for a roller for a fixing device, and to improve the performance of the roller for a fixing device.

In order to achieve the above object, the present invention provides a roller for a fixing device, which has a roller body and an elastic surface layer that can be attached to and detached from the roller body in the axial direction of the body.

Embodiments of the present invention will be described below with reference to the drawings. An example in which the present invention is applied to a pressure roller provided in a fixing device of an electrophotographic copying machine will be explained with reference to FIGS. 1 and 2. FIG.

FIG. 1 illustrates a cross section of the fixing device in the direction of roller rotation. / is a fixing roller, which has a heating heater 13 such as a halogen heater inside. The fixing roller L is a hollow roller core made of metal such as aluminum, stainless steel, or copper, and a heat-resistant release resin layer such as tetrafluoroethylene resin is coated on the outer peripheral surface of the roller core.
It is provided with a thickness of 100μ.

- is a pressure roller which, together with the fixing roller l, pinches and conveys the plain paper supporting the toner image to perform the fixing process. The fixing roller l and the pressure roller are rotatably supported by the fixing device, and the pressure roller is urged by a known pressure means so as to come into pressure contact with the fixing roller l at least during fixing.

The configuration of the pressure roller is explained in detail in Figure 1, and it consists of a roller body with a relatively thick elastic layer bonded to the outer circumferential surface of a metal roller core U, and a roller body with comparatively high heat resistance and mold release properties. It consists of a heat-resistant releasable coating 23, which is a thin tube-shaped stretchable elastic body that is removably attached to the roller body.

Rubber materials such as silicone rubber, fluororubber, fluorosilicone rubber, urethane rubber, ethylene propylene rubber, and nitrile rubber are suitable for this elastic layer 24. The main requirement for these rubber materials is rubber strength.
What is the thickness of the elastic layer here (lI)? R-10IIHII is good. In addition, the heat-resistant mold-releasing coating 23 is made of a material exhibiting mold-releasing properties such as a silicone rubber tube, and the thickness is O9θ/III~, 711.
Around 11 is good.

The configuration of the pressure roller is such that a relatively thick elastic layer of the roller core material mainly secures a pressure contact area with the fixing roller, and a relatively thin heat-resistant and releasable coating 23 provides surface heat resistance and surface releasability. It is held by a pressure roller.

A temperature sensing element such as a thermistor or thermocouple is arranged in contact with the outer peripheral surface of the fixing roller l, and its detection signal is guided to a known control means (not shown) to control the temperature of the outer peripheral surface of the fixing roller l (heater). The toner image melting temperature is maintained by controlling the output of 13 or its applied voltage, etc.).

The separating means 3 that comes into contact with the circumferential surface of each roller has a plurality of separating claws si and is for reliably separating the recording material after fixing from the roller.

Reference numeral 6 denotes a cleaning member for removing foreign matter such as offset toner and paper powder adhering to the heating roller surface from the roller surface, and a cleaning web 61 made of a heat-resistant nonwoven fabric such as Nomex or Himeron is used.

The cleaning web 61 is moved by a fixing roller l by a pressing roller t3 having elasticity such as silicone rubber, fluoro rubber, fluorosilicone rubber, or silicone rubber sponge.
Also, this web 6/ in contact with the cleaning web 61 is moved by a driven take-up roller 6S from the supply roller 6:1 so as to change its contact position little by little, so that a new surface of the cleaning web 61 is always created. It comes into contact with the heating roller.

Next, referring to FIG. 2, a detailed explanation of the pressure roller will be given.

A roller core material shown in Figure 1 is manufactured as a roller body.

This is unvulcanized silicone rubber (KE-RIILλ mite 1
□A, -), 1-4, 6. . -18, Cradle, unvulcanized rubber sheet left at room temperature for 3 days, and outer diameter S
With a flange with an axial length of 3λθ at O ■ After blasting the stainless steel core metal, apply adhesive to the surface and leave it in an environment of 1.23℃ for an hour, and then heat it for 120 minutes.
Manufactured with a core metal that has been baked at ℃ for 20 minutes.

The core metal is covered with the unvulcanized rubber sheet, and the pressure / j
(Second vulcanization was performed at 7'f/am2, temperature/70°C for 30 minutes (using a press vulcanizer).Furthermore, after secondary vulcanization at -00°C for an incubation time, the outer diameter A roller core material consisting of a metal core and a (high temperature vulcanization type) HTV silicone rubber layer was manufactured by grinding to s9■.

Subsequently, a tube shown in FIG. 1 is manufactured as a heat-resistant releasable coating 23.

The tube as layer 3 is filled with silicone oil about 27
A thin heat-resistant releasable coating made by injection molding of room temperature vulcanizable (RTV) silicone rubber (Shin-Etsu Chemical, KFi-/R) containing 7 wt%.

~lθOμ) Attach a rubber surface coating. A heat-resistant releasable coating is formed by winding a thin tube into a donut shape with a ring ring 37 having a relatively thick circular cross section at both ends, and the ring ring 31 whose inner diameter is smaller than the outer diameter (g) of the elastic layer two is used as an elastic layer. - It is attached to the surface of the elastic layer of the core material while being unwound in the direction of arrow S.

By attaching it in this way, it is not only easier to attach it, but also allows the surface of the elastic layer 1 of the core material and the inner surface of the heat-resistant mold release coating 3 to be in close contact with each other without introducing air bubbles. , it was possible to prevent the surface coating layer from shifting and wrinkling during fixing.

In particular, if the thickness of the heat-resistant mold release coating 3 is less than ioμ, it may not have sufficient elastic force and may shift.
If the roller length is 32011111, the thickness of the heat-resistant releasable coating 23 is θθμ, and the thickness of the end ring λ3/ is also added to the cross-sectional diameter of the donut. However, the size is 2j-1111 or more, which not only requires a large force when installing, but also has a large difference in elongation between the front end and the rear end during storage, making it impossible to install with uniform tightening pressure.

In the above-mentioned pressure roll roller, as mentioned above, the heat-resistant release coating 23 can be detached and functionally separated from the roller body.
In particular, the material can be selected with emphasis on the functions required for the surface layer, such as mold releasability and heat resistance. In addition, the physical strength required for the core material (compression set, rubber elasticity, etc.)
We were able to select materials by taking these factors into consideration. Therefore, a pressure roller with good functionality could be manufactured without any major limitations. In the fixing device shown in Fig. 1, the fixing roller/
A roller with an outer diameter of 6θ and a 30μ thick PTA coating layer on an aluminum core metal with a wall thickness of ■ is pressed against the above pressure roller at a total pressure of AOKg, and the fixing roller surface temperature/gθ
±o,; Under the conditions of 'c, 3 sheets of A3 size paper/minute (
The toner image was fixed on the recording material at a roller circumferential speed of approximately 270 m+/5ea). As a result, it was confirmed that the heat-resistant releasable coating 3 was in close contact with the elastic layer 1, so the pressure roller could be used without any problem, and since mold releasability could be prioritized, there was little staining.

Normally, the pressure roller is a separation claw that comes into contact with the surface! The surface layer is slightly abraded due to R-coating, recording materials, etc., and there is a slight deterioration in mold releasability over time, but since only the heat-resistant mold release coating 23 can be replaced with a new one, the initial characteristics will be restored again. I was able to use it without any problems.

On the other hand, in conventional pressure rollers in which rubber properties are emphasized and the roller core material is made of a single layer of HTV silicone rubber as the surface layer, the surface becomes conspicuously dirty and the time for replacement is premature. As a countermeasure to this problem, even if a rubber layer after vulcanization was immersed in a release agent such as silicone oil to swell the rubber layer, the roller was still easily stained. Also, the RT used for the pressure roller and the heat-resistant mold release coating 3
When the pressure roller was constructed of only V-silicone rubber and metal core metal, there was little dirt, but physical strength was not obtained, and the roller surface was permanently deformed when left under pressure, and the dents caused abnormal sounds when driven. Also, for this purpose, a pressure release mechanism is installed.
In addition, with the above configuration of the pressure roller, 22. and 3 are stuck to each other and cannot be detached. ), if a thick HTV silicone rubber layer and a thin RTV silicone rubber layer are integrally bonded and molded to each other on a metal core in that order, manufacturing the roller is complicated and requires many man-hours, making it expensive. Moreover, even if only the surface layer of the RTV silicone rubber deteriorates, the entire pressure roller must be replaced with a new one, which is uneconomical.

Next, as a fourth embodiment of the present invention, an example in which the fixing member of the present invention is applied to a fixing roller will be described with reference to FIGS. 3 to 11.

First, the features of this embodiment will be explained using FIG. 3 and FIG. q. In a fixing device that performs pressure and heat treatment by sandwiching and conveying an object to be fixed between at least a pair of opposing rollers, both the fixing roller on the side that contacts the toner image and the pressure roller that opposes it have an elastic material on their surfaces. If the coating is applied, good fixing performance can be obtained. This is due to the following reasons. FIG. 3 shows a fixing device having the configuration shown in FIG. 1, in which a heat-resistant release resin layer such as PFA resin is coated on the outer peripheral surface of a metal hollow roller core as a fixing roller l.
A highly rigid roller set at 0μ pressure was used, and a highly elastic roller with a relatively thick (approximately 5 to iowx) layer of elastic material such as silicone rubber on the outer peripheral surface of a metal roller core was used as the pressure roller. FIG. 2 is an enlarged schematic diagram of a nip portion when a recording material carrying a toner image is fixed in the system. When the recording material P carrying the toner image T enters between the pair of rollers, the upper layer of the toner image T in contact with the fixing roller I is immediately softened and melted by receiving heat from the fixing roller I having the halogen heater 13, and the toner particles Increases cohesion.

However, in order for the toner in the lower layer, which is closer to the side of the recording material P, to receive sufficient heat to soften and melt, it usually takes a longer time (approximately 1//θo-s/100 seconds) than the toner in the upper layer. When the toner enters the image, the toner at the periphery of the image is dislodged or thrown out due to the supply of heat and the pressure between the pair of rollers that are in contact with each other. In this case, the toner in the lower layer of the toner image T softens and melts more slowly than the toner in the upper layer, and thus has a weak cohesive force and is particularly susceptible to its influence. At the same time, a gap as shown in FIG. 3 occurs between the fixing roller, the recording material P, and the toner image T.

Toner separated from the toner image T as described above scatters in this gap S, and if it adheres to the recording material P, it will cause image disturbance (stirring), or if it adheres to the fixing roller L, it will cause an offset. Further, in FIG. 3, the broken line indicates the bulge of the toner image T caused by the pressure after fixing.

As shown above, when the surface of the fixing roller has high rigidity, the gap S is large, resulting in poor heat transfer efficiency to the toner image, that is, poor fixing performance.

In addition, the unmelted toner pushed out into the gap scatters onto the recording material P and the fixing roller L, resulting in a large deterioration in image quality and a large amount of offset.

Next, FIG. 7 shows the toner image T in a system using a relatively thin heat-resistant release elastic roller such as RTV silicone rubber as the fixing roller door and a relatively thick elastic roller such as HTV silicone rubber as the pressure roller. Recording material P carrying
FIG. 3 is an enlarged schematic diagram of the nip portion when the image is fixed.

In this case, since the fixing roller 11 is an elastic body, the fixing roller 11 also follows the convex portion of the toner on the recording material P, and the gap S
1 is very small, the heat transfer efficiency to the toner is good, and the fixing property is very good. at the same time,
The bulge D' of the image is also small, and since the gap day 1 is very small, offset and blurring are also reduced. Further, since the offset is very small, the cleaning device shown in FIG. 1i is not necessarily required.

However, compared to the heat-resistant mold-releasing resin described above, the heat-resistant mold-releasing elastic body described above has lower physical strength, so the separation claw 3
1 and temperature-sensitive elements, etc., and is also susceptible to performance deterioration such as damage to the surface layer and deterioration over time. In that case, the entire fuser roll needs to be replaced, which increases costs, etc. This may cause such inconvenience. The above inconvenience has been revised 1.
In order to improve the quality of the product, attempts have been made to improve the physical strength by sacrificing some of the mold releasability, but this not only increases the likelihood of paper jamming and other problems, but also reduces reliability.
In the event of a jam, the rollers would be subject to excessive pressure due to the jammed paper, which could result in damage to the receiver.

Therefore, in this example, in a fixing roll provided with a heat-resistant release elastic layer on the surface, which has good fixing performance although its durability is slightly inferior, the heat-resistant release elastic layer surface coating and the roll core material are simplified. By configuring the fixing roll to be detachable from the fixing roll, a fixing roll having good fixing performance is provided.

FIG. 3 shows a fixing device to which the fixing roll of the present invention can be applied.
This is an example. Components and functions similar to those in FIG. 1 are designated by the same numbers, and descriptions thereof will be omitted.

In this embodiment, since the offset is very small, the cleaning member t shown in FIG. 1 can be removed. In this case, the extremely small amount of offset toner is such that it does not cause a deterioration in image quality, and it is sufficient to deposit it on the image area of the recording material P each time. That is, it is possible to cause the recording material P to function as a cleaning member. Alternatively, when there is no recording material P between the rollers, a small amount of offset toner to the fixing roller door is transferred to the pressure roller side, that is, the pressure roller acts as a cleaning roller for the fixing roller /', and the small amount of toner adhering to the pressure roller is removed. The toner may be cleaned by a cleaning member S provided in contact with the pressure roller (FIG. 3 shows the latter configuration). The cleaning member t may be a simple member such as felt. With such a configuration in which the cleaning member is not brought into contact with the fixing roller door, wear on the surface of the fixing roller 11 can be reduced, and the life of one surface coating layer can be extended. In Figure S, the pressure roller has a total length of J 30 II.
Im, an elastic layer such as HTV silicone rubber, 24 (glue) on the outer peripheral surface of the metal roller core with flanges on both ends
It has an outer diameter of 60 mm and is set at a pressure.

The fixing roller 11 of the present invention is manufactured by the following manufacturing method.

To create the roller core material, unvulcanized heat-curable silicone rubber (manufactured by Toshiba Silicone: Tel!+-10-jU) is sufficiently kneaded with a vulcanizing agent to form an unvulcanized rubber sheet. /4I left at room temperature for 3 days was prepared. Next, the outer diameter is 39.0■wall thickness■, and the total pipe length is 330w.
5. Aluminum hollow core bar with flanges on both ends (Ato, t
After blasting and cleaning the roller core 12 in a), apply adhesive and leave it in a controlled environment for 3 hours, then 12
Baking was performed at 0°C for 20 minutes. Thereafter, the roller core/2 is coated with the unvulcanized rubber sheet llI,
Pressure 13θKf/m2. After secondary vulcanization at 0°C for 20 minutes and further secondary vulcanization at 200°C for 3 hours, the shape was as shown in Figure 6 with an outer diameter of 59. After a rough search, the material was used as the core material. The rubber sheet III was also applied to the stepped end face of the roller core I to cover a length of 41 m. In addition, three screw holes were provided at equal pitches on the same circumference on the stepped end face of the roller core l.

Next, a procedure for creating the heat-resistant and releasable elastic coating lj will be described.

Unvulcanized room temperature vulcanizable silicone rubber (manufactured by Toshiba Silicone Rubber: TsF!3ho3) was injected into a mold after adding a vulcanizing agent, left for 3 days, removed from the mold, and heated at 1000°C for 3 days.
θ minutes, 1 hour at /lOc, λ hours at tgo”c, 200
The second vulcanization was carried out at ℃ for 3 hours, and the inner diameter kf, 4tw, and outer diameter were obtained as shown in Fig. 7! r! r, owa, full length 3SOI
Finished in an IOI+ (larger than the total length of the pipe) shape.

A heat-resistant, releasable elastic coating/j was applied to the fixing roller core 7.2 individually prepared as described above, as shown in FIG. g. At the time of installation, both ends of the heat-resistant, releasable elastic coating 15 were also applied to the stepped ends of the rubber sheet llI.

The fixing ring is an annular fixing ring with round holes for screws lθ equally spaced on the same circumference and a flat outer surface and a rounded convex large diameter portion on the inner surface. The heat-resistant and releasable elastic coating on the end face is attached so as to press the
A screw 10 is inserted into the round hole of the fixing ring 7, and the roller core 1
It is screwed into the screw hole 9 of No.2.

Outer surface of 14t rubber sheet and heat-resistant mold release elastic wave -〇'”
(7) I'9M1i″Bltc!=tij&!J°″”
Since the 70 coefficient is high, misalignment between the roller core 1, the rubber sheet 1, and the heat-resistant and releasable elastic coating 13 is less likely to occur. In addition, since the stepped end surface of the fixing roller 11 is fixed with a fixing ring, the heat-resistant and releasable elastic coating 13 may be inadvertently moved in the circumferential direction or the roller core 12.
Axial displacement is prevented.

When the fixing process was performed at the same speed as in the first embodiment using the fixing device shown in FIG. 3 using the fixing roller of the present invention,
Very good results were obtained.

Also, if you replace the surface coating layer once for each SaOθθ sheet, 1.
Even after running yoaoooo sheets, the results were exactly the same as the initial results.

Of course, it is also possible to have a configuration in which both the fixing roller/1 and the pressure roller of the present invention described above are combined.

Still another embodiment is shown in the perspective view of FIG. Fixing roller/
1 or when attaching a heat-resistant releasable elastic coating to the core material of the pressure roller, the inner diameter of which is smaller than the outer diameter of the core material, a ring/A whose inner diameter is larger than the outer diameter of the core material (operability Taking into consideration the width of the tube (width is about 10 to -0 cm), cover the tube with the tip of a tube for heat-resistant, releasable elastic coating (lde), enlarge the diameter of the tip of the tube, and then A lubricant such as non-heat resistant molybdenum disulfide is applied to the tube 17, and the tube 17 is attached to the core material by pulling the portion where the tube 17 covers the ring. After installation, the ring 16 is removed and the end portion is cut off.

When this roller is used in the fixing roller door or pressure roller of the fixing device, the lubricant is squeezed out by the pressure of the opposing roller during fusing, and the remaining lubricant does not lose its slipperiness due to thermal deterioration. To make it difficult for the tube 17 to shift.

In particular, when using a pressure roller that rotates following pressure contact with an opposing roller, in addition to the non-heat resistant lubricant mentioned above, a heat resistant lubricant such as silicone grease or silicone oil is used as the lubricant. The core material and the core material may slip.

Another embodiment is shown in longitudinal cross-sectional views in FIGS. 1θ, 1I, and 1C, showing the end stop means of the heat-resistant and releasable elastic coating. A roller core material in which an elastic layer 19 is provided on a metal core metal/g is provided with grooves 2o at both ends (θ). A tube 1 as a heat-resistant, releasable elastic coating shown in Fig. 1 is attached to the core material, and a ring 1 shown in Fig. 1 is attached.
6' into the groove J (located opposite to 7).

Ring/A' is a copper-based or Ni-Ti-based shape memory alloy, and has transformation points at ioθ°C and 3θ°C.

Therefore, during fixing, the silicone rubber tube 17 can be fixed to the core material because a phase transition occurs and the diameter becomes smaller. Furthermore, since the temperature is room temperature (33° C. or lower) when the core material is attached, the inner diameter is larger than the outer diameter of the core material, making it easy to attach and detach. A tube in which a shape memory alloy is integrally molded in a mesh or spiral shape may also be used.

In this embodiment, an example in which the present invention is applied to a pressure roller and a fixing roller of a heat fixing device is described, but it is of course applicable to a cleaning roller of a fixing device and a pressure fixing device having an elastic coating layer. .

As described above, in the above embodiments, one surface coating layer and a core material are configured to be easily attachable and detachable in fixed layer members such as a fixing roller and a fixing belt that have a surface coating layer, so that only one surface coating layer can be used. In the case of deterioration, it is possible to replace only the surface coating layer, which enables low-cost maintenance, and allows the functions of the core material and surface coating layer to be separated and designed, so that the core material and the surface coating layer can be designed separately. It has also become possible to greatly improve the functionality of the device.

Therefore, it was possible to provide a fixing device that performs good fixing over a long period of time. The present invention is a roller for a mud layer device having an innovative configuration.

Costs and materials can be reduced, and characteristics can be further improved depending on the purpose.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a fixing device to which the present invention can be applied, and FIG.
The figure is a longitudinal cross-sectional view of an embodiment of the present invention, FIGS. 3 and 4 are schematic diagrams illustrating the fixing properties of a fixing device to which the present invention is effectively applied, and FIG. FIG. 6, FIG. 7, and FIG. 5 are vertical cross-sectional views showing other embodiments of the present invention, and FIG. 9 is a perspective view showing still another embodiment. , Fig. 10, @// Fig. 1, and Fig. 1 are longitudinal sectional views of other embodiments. /'... Fixing roller -... Pressure roller g...
Cleaning member /2...Roller core llI...
Rubber sheet ls...Heat-resistant releasable elastic coating /A. /A' 3/...Ring /7...Tube 7
g...Core metal 79...Elastic body #, 2o...Groove...Roller core Here, here...Elastic body Ft! t, 1
3...Suffering from secondary heat mold release.

Claims (1)

[Claims] 1. A fixing roller having a structure in which a roller body and a surface elastic layer can be attached and detached in an axial direction of the roller in an end region of the roller, the fixing device having an engaging portion between the roller body and the surface elastic layer. roller.