JP2009271432A - Fixing roller, fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing roller and a fixing device, which never cause fixing failure by preventing twisting of a metal layer, and can be quickly started and extended in life. <P>SOLUTION: A central elastic layer 1b is laminated on a core metal 1a, and a metal sleeve 1c is provided on the circumference thereof. Sleeve movement preventing members 11 and 11 are inserted from both sides of the central elastic layer 1b and positioned by stop rings 7 from the outside. Each circumferential portion of the sleeve movement preventing members 11 and 11 is adhered to the metal sleeve 1c through an adhesive layer 6. The metal sleeve 1c is regulated in axial movement (shift) by the sleeve movement preventing members 11 and 11. Since the metal sleeve 1c is not adhered to the central elastic layer 1b, release of heat from a heating layer (metal layer) to the elastic layer can be reduced to shorten the start-up time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fixing roller and a fixing device used in an image forming apparatus such as a copying machine, a printer, and a facsimile.

JP 2005-49812 A

  As a fixing device in an image forming apparatus such as a copying machine, a printer, or a facsimile, a recording medium (paper) carrying an unfixed image is sandwiched and conveyed between a fixing roller and a pressure roller, and the unfixed image is placed on the paper by heat and pressure. Thermal fixing devices for fixing to are well known.

Conventional fixing devices are mainly provided with a fixing heater such as a halogen lamp as a heat source, and the fixing roller is heated by the fixing heater.
However, such a heating method using a heater requires a long time until the fixing roller is heated to a necessary temperature, and the loss of the heater itself is large, so that a fixing device with high efficiency and quick rise time is required. Yes.

  In such a situation, the fixing device using the induction heating method can instantaneously heat the fixing roller by eddy current due to electromagnetic induction, so that the start-up time can be shortened dramatically. This halogen lamp method eliminates the need for preheating, eliminates unnecessary electric power, and is superior in heating efficiency, and is therefore attracting attention as an advantageous method for environmental problems.

  FIG. 14 is a cross-sectional view schematically showing an example of a conventional fixing device. As shown in this figure, the pressure roller 102 is in pressure contact with the fixing roller 101. An induction heating device 103 having a core 104 and a coil 105 is disposed on the outer peripheral portion of the fixing roller 101 to heat the fixing roller 101 by eddy current due to electromagnetic induction. A recording medium P such as transfer paper carrying an unfixed toner image passes through a nip formed by pressing the pressure roller 102 against the fixing roller 101, and the unfixed toner image is recorded on the recording medium P by heat and pressure. Fixed on top.

  As shown in FIG. 15A, the fixing roller 101 is formed by laminating an elastic layer 101b on a cored bar 101a, and further providing a metal sleeve 101c as a heat generating layer outside the elastic layer 101b. In such a configuration, if the deviation of the metal sleeve 101c is not restricted by any means, the metal sleeve 101c is shifted in one of the axial directions (either in the left or right direction in the drawing) with the rotation of the roller, and is damaged. There are various factors such as a slight difference in the outer diameter of the sleeve and the elastic layer and a slight difference in the applied pressure on the left and right (on both sides in the axial direction). It is difficult to do.

  As a method of regulating the shift of the metal sleeve, as shown in FIG. 5B, a method of bonding the elastic layer 101b and the metal sleeve 101c, or, for example, as shown in FIG. A method can be considered that uses 107 to suppress the problem by a method other than adhesion.

  The method of bonding the elastic layer 101b and the metal sleeve 101c is advantageous in that the structure is simple and the reliability is relatively high. However, by bonding the elastic layer and the metal sleeve, (1) the amount of heat escaping from the metal layer to the elastic layer is increased, the rise is delayed, and (2) the metal layer is bonded to the elastic layer. There is a demerit that it becomes difficult to deform, a nip is difficult to come out, and a fixing failure is likely to occur.

In addition, the fixing roller having such a configuration has a problem that the roller life is shortened due to the destruction of the metal sleeve or the foaming foam as the elastic layer.
Furthermore, as shown in FIG. 16, even when the adhesive is applied only to both ends of the elastic layer 101b, the sleeve 101c spreads the adhesive when the sleeve 101c is inserted, and the adhesive is applied only to both ends. It was difficult to paint.

  In Patent Document 1, only a thin metal conductive layer (heat generation layer) and an end portion of a foamed rubber layer (elastic layer) are bonded, and the metal conductive layer and the foamed rubber are formed at the center in the longitudinal direction (roller axial direction). Heating rollers have been proposed in which voids are formed between the layers.

  However, in the heating roller described in Patent Document 1, since the end portion and the center portion of the foam rubber layer (elastic layer) are integrally formed, each of the center rubber layer and the end rubber layer is formed. Free deformation is hindered, and there is a risk that a nip will be difficult to come out near the boundary surface between the center and the end (necessary nip width cannot be obtained). Further, as described with reference to FIG. 16, it is impossible to prevent the adhesive from spreading to the center.

  Furthermore, Patent Document 1 exemplifies a configuration in which the elastic layer at the center is relatively small and soft, and the elastic layer at the end is large and hard. Only the elastic layer at the end is in contact with and deformed with the metal layer, and the elastic layer at the center is not in contact with the metal layer and is not deformed. Therefore, a necessary nip cannot be obtained and fixing failure may occur. If the center elastic layer is pressed to the extent that it is in contact with the metal layer in order to obtain the required nip, the deformation amount of the elastic layer at the relatively large and hard end increases, and the life of the end elastic layer is shortened. There is also a fear.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems in the conventional fixing roller and fixing device, and to provide a fixing roller, a fixing device, and an image forming apparatus that have a fast life and do not cause a fixing failure and have a long life.

  According to the present invention, there is provided a fixing roller having an elastic layer at a central portion in the longitudinal direction of the roller, and a metal sleeve provided outside the central elastic layer, in the longitudinal direction of the central elastic layer. A sleeve movement preventing member for restricting movement of the metal sleeve in the roller longitudinal direction is disposed on both sides, the sleeve movement preventing member has an elastic layer, and the elastic layer becomes an inner peripheral layer of the metal sleeve. Is solved.

Further, it is preferable that the outer peripheral portion of the elastic layer of the sleeve movement preventing member is bonded to the metal sleeve.
Further, it is preferable that the hardness of the central elastic layer is larger than the hardness of the elastic layer of the sleeve movement preventing member.

Moreover, it is preferable that the hardness of the elastic layer of the sleeve movement preventing member is 3 to 10 degrees, more preferably 5 to 8 degrees in Asuka C hardness, which is smaller than the hardness of the central elastic layer.
The elastic layer of the sleeve movement preventing member is preferably a solid rubber.

Moreover, it is preferable that the outer diameter of the central elastic layer is smaller than the outer diameter of the elastic layer of the sleeve movement preventing member and smaller than the inner diameter of the metal sleeve.
The length of the metal sleeve in the roller longitudinal direction is smaller than the length of the central elastic layer plus the length of the elastic layer of the sleeve movement preventing member on both sides of the central elastic layer. And preferred.

Further, it is preferable that the elastic layer of the sleeve movement preventing member has a large-diameter portion located outside the end surface of the metal sleeve and having a diameter larger than the outer diameter of the metal sleeve.
Further, the elastic layer of the sleeve movement preventing member has a plurality of convex portions projectingly contacted to the outer peripheral side at a portion located inside the metal sleeve, and the plurality of convex portions are inner peripheral surfaces of the metal sleeve. Is preferably engaged.

  In addition, the elastic layer of the sleeve movement preventing member has a plurality of convex portions protruding in contact with the outer peripheral side at a portion located inside the metal sleeve and arranged in parallel in the circumferential direction, and in the vicinity of the end of the metal sleeve It is preferable to provide a plurality of holes into which the plurality of convex portions are fitted.

  Further, the sleeve movement preventing member includes an outer diameter increasing means for increasing the outer diameter of the elastic layer of the sleeve movement preventing member, and the outer diameter increasing means causes the outer periphery of the elastic layer of the sleeve movement preventing member to be inside the metal sleeve. It is preferable to press the circumference.

Moreover, the said subject is solved by the fixing apparatus provided with the fixing roller of any one of Claims 1-11 by this invention.
In addition, according to the present invention, the above problem is solved by an image forming apparatus including the fixing device according to claim 12.

  According to the fixing roller of the present invention, by disposing the sleeve movement preventing members on both sides of the central elastic layer, the shift of the metal sleeve is restricted, and the damage of the metal sleeve due to the rotation of the roller can be prevented. As a result, the life of the fixing roller can be extended. In addition, since the central elastic layer can be non-adhered to the metal sleeve, and a necessary nip can be obtained, it is possible to prevent the occurrence of fixing failure.

  According to the configuration of the second aspect, the elastic layer outer peripheral portion of the sleeve movement preventing member can be adhered to the metal sleeve to reliably restrict the movement of the sleeve. Further, the adhesive is not spread on the central elastic layer.

  According to the configuration of the third aspect, in the configuration in which the outer peripheral portion of the elastic layer of the sleeve movement preventing member is bonded to the metal sleeve, a nip equivalent to the central portion can be obtained at the roller end portion, and fixing failure can be prevented. it can.

According to the configuration of the fourth aspect, it is possible to effectively prevent the nip reduction at the roller end portion and to prevent the elastic layer from being damaged at the roller end portion.
With the configuration of the fifth aspect, it is possible to more effectively prevent the elastic layer from being damaged at the roller end.

According to the configuration of the sixth aspect, by making the central elastic layer non-contact with the metal sleeve, heat escape from the metal sleeve to the central elastic layer is reduced, and the warm-up time can be shortened.
According to the configuration of the seventh aspect, it is difficult to receive stress concentration of the elastic layer at both ends of the roller, and the life of the metal sleeve can be extended.

  According to the configuration of the eighth aspect, the shift of the metal sleeve can be regulated by the large diameter portion provided in the elastic layer of the sleeve movement preventing member. In addition, the sleeve movement preventing member can be non-adhered to the metal sleeve, reducing heat escape and preventing deformation of the metal layer due to adhesion, and a necessary nip at the roller end. Obtainable.

According to the configuration of the ninth aspect, the plurality of convex portions provided on the elastic layer of the sleeve movement preventing member can be engaged with the inner peripheral surface of the metal sleeve to effectively restrict the movement of the sleeve.
With the configuration of the tenth aspect, the plurality of convex portions provided on the elastic layer of the sleeve movement preventing member are fitted into the holes of the metal sleeve, so that the movement of the sleeve can be more effectively regulated.

According to the configuration of the eleventh aspect, the outer peripheral portion of the elastic layer of the sleeve movement preventing member is pressed against the inner periphery of the metal sleeve by the outer diameter increasing means, so that the movement of the sleeve can be reliably controlled.
According to the fixing device of the twelfth aspect, it is possible to realize a fixing device that rises quickly and does not cause a fixing failure. In addition, a fixing device having a long life can be realized.

  According to the image forming apparatus of the thirteenth aspect, since the fixing device rises quickly and does not cause a fixing failure, a rapid first print can be realized and an image with excellent fixing properties can be obtained. it can.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing a first embodiment of a fixing roller according to the present invention. In the fixing roller 1 shown in this figure, a central elastic layer 1b is laminated at a central portion in the longitudinal direction (axial direction) of a core metal 1a, and a metal sleeve 1c is provided on the outer periphery of the central elastic layer 1b. Sleeve movement preventing members 11 and 11 are disposed on both sides of the central elastic layer 1b, and a retaining ring 7 is disposed on both sides (axially outside).

  The sleeve movement preventing member 11 is formed by laminating an elastic layer 11b on the outer side of a perforated core metal 11a provided with a hole for fitting into the core metal 1a. Directional movement is restricted. The outer peripheral portions of the sleeve movement preventing members 11, 11 are bonded to the metal sleeve 1 c by the adhesive layer 6. The elastic layer 11b of the sleeve movement preventing member 11 is disposed on both sides of the central elastic layer 1b and is located at the end in the roller axial direction. Hereinafter, the elastic layer 11b of the sleeve movement preventing member 11 is referred to as “end elastic”. This is referred to as layer 11b ".

  The core metal 1a and the perforated core metal 11a are preferably made of aluminum, iron, stainless steel (SUS), or the like. As the center elastic layer 1b and the end elastic layer 11b, foamed silicon rubber is suitable. The metal sleeve 1c serving as the heat generating layer is preferably made of stainless steel, nickel (Ni), copper (Cu), iron or the like. Although not shown in the figure, on the outside of the metal sleeve 1c, a rubber layer (silicone rubber or fluororubber is preferable) for improving the image quality, or a release layer (for example, PFA or the like) for preventing toner from sticking. PTFE or the like is preferred).

  In the fixing roller 1 of this example configured as described above, the sleeve movement preventing members 11 and 11 are fitted into the core metal 1a from both sides of the central elastic layer 1b laminated on the core metal 1a, and the sleeve movement preventing member 11 is inserted. , 11 is bonded to the metal sleeve 1c and the sleeve movement preventing members 11 and 11 are restricted from moving in the axial direction by the retaining ring 7, so that the shift of the metal sleeve 1c in the axial direction is restricted, and the rotation of the roller At the same time, the metal sleeve is prevented from being damaged.

  Further, by setting the sheet passing area between the sleeve movement preventing members 11 and 11 on both sides, the elastic layer (end elastic layer 11b) is bonded to the metal sleeve 1c only in the non-sheet passing area at both ends of the roller. Since the metal sleeve 1c and the central elastic layer 1b are not bonded at the central portion in the roller axial direction, which is a sheet passing area, heat escape from the heat generation layer (metal layer) to the elastic layer in the fixing roller is reduced. Thus, it is possible to prevent the metal sleeve 1c from shifting in the axial direction without delaying the rise time.

  Further, since the central elastic layer 1b and the end elastic layer 11b are not bonded and configured as separate bodies, the hardness of the central portion and the end portion in the roller axial direction are different, or the roller outer diameter is different. Can also be realized easily. For example, the hardness can be easily varied by changing the material between the center elastic layer 1b and the end elastic layer 11b or changing the foaming rate.

FIG. 2 is a schematic diagram showing a method for producing the fixing roller 1 of this example.
As shown in this figure, after inserting the metal core 1a having the central elastic layer 1b laminated into the metal sleeve 1c, the adhesive 6 is applied to the outer periphery of the elastic layer (end elastic layer 11b) of the sleeve movement preventing member 11. Then, the sleeve movement preventing member 11 is inserted into the metal sleeve 1c to form the fixing roller 1. According to this production method, the adhesive (adhesive layer 6) applied to the outer periphery of the sleeve movement preventing member 11 does not protrude (spread) into the central elastic layer 1b.

  FIG. 3 is a sectional view showing a second embodiment of the fixing roller according to the present invention. The basic configuration of the fixing roller 10 of the second embodiment is the same as that of the fixing roller 1 of the first embodiment described above, and a description thereof will be made with a focus on different parts, without redundant description. In addition, the corresponding parts will be described with the same reference numerals.

  In the fixing roller 10 of the second embodiment, the hardness of the central elastic layer 1b is larger (harder) than the hardness of the end elastic layer 11b (the elastic layer of the sleeve movement preventing member 11). That is, the hardness is lower at both ends of the roller than at the center. By making the end elastic layers 11b and 11b relatively soft, even if the elastic layer is bonded to the metal sleeve 1c at this portion (both ends of the roller), the metal layer is not separated from the elastic layer (central elastic layer 1b). A nip equivalent to the center of the roller, which is bonded, can be obtained at both ends of the roller.

  In this example, the hardness of the central elastic layer 1b was 28 to 32 degrees in rubber hardness (Asuka C hardness), and the end elastic layer 11b was 23 to 27 degrees in rubber hardness (Asuka C hardness). With this configuration, even if the metal sleeve 1c and the end elastic layers 11b and 11b are bonded to both ends of the roller, the nip is not narrow (the length in the paper passing direction) is not fixed at the end of the roller, and fixing failure occurs. I did not wake up. In the second embodiment, as shown in FIG. 3, the paper passing area can be expanded to the end elastic layers 11b and 11b, and the total length (axial length) of the fixing roller can be shortened. An increase in the size of the apparatus can be suppressed. Of course, as in the first embodiment, the central elastic layer 1b can be set as the paper region.

  The hardness of the central elastic layer 1b and the hardness of the end elastic layer 11b are 3 to 10 degrees, more preferably 5 to 8 degrees in rubber hardness (Asuka C hardness) as the hardness of the end elastic layer 11b. It may be lower than the hardness of 1b. A difference of 2 degrees or less in rubber hardness cannot prevent a decrease in nip due to adhesion of end portions, and if the difference is too large (if the end elastic layer 11b is too soft), a necessary nip is required. There is a possibility that the end elastic layer 11b breaks when the pressure is applied so as to obtain. Therefore, it is not preferable that the rubber hardness differs by 10 degrees or more between the roller center and the end. In addition, it is also preferable that the end elastic layer 11b is made of solid rubber so that no bubble breakage occurs in the end elastic layer 11b.

  FIG. 4 is a sectional view showing a third embodiment of the fixing roller according to the present invention. The basic configuration of the fixing roller 20 of the third embodiment is the same as that of the fixing roller 1 of the first embodiment described above, and overlapping description will be omitted and different parts will be mainly described. In addition, the corresponding parts will be described with the same reference numerals.

  As shown in FIG. 4, in the fixing roller 20 of the third embodiment, the outer diameter (diameter) of the central elastic layer 1b is the outer diameter of the end elastic layer 11b (the elastic layer of the sleeve movement preventing member 11). The diameter of the metal sleeve 1c and the central elastic layer 1b are not in contact with each other, and there is a gap between the metal sleeve 1c and the central elastic layer 1b. As an example, the outer diameter of the central elastic layer 1b is 39.8 mm, the outer diameter of the end elastic layer 11b is 40.2 mm, and the inner diameter of the metal sleeve 1c is 40.0 mm. At this time, since the central elastic layer 1b is not in contact with the metal layer (sleeve 1c) except at the nip portion, the heat escape from the metal sleeve 1c to the central elastic layer 1b is reduced, and the warm-up time is shortened. It becomes possible.

  The outer diameter of the center elastic layer 1b and the outer diameter of the end elastic layer 11b are appropriately 0.2 to 0.7 mm, and more preferably 0.2 to 0.4 mm. If the outer diameter difference of the elastic layer is larger than 0.7 mm, even if the fixing roller is pressed against the pressure roller at the nip portion, a sufficient nip cannot be obtained due to the small diameter of the central portion, resulting in poor fixing. There is a possibility of waking up. Moreover, when the outer diameter difference is less than 0.2 mm, the effect of reducing the outer diameter of the central elastic layer cannot be sufficiently obtained.

  Thus, in the fixing roller 20 of the third embodiment, the outer diameter of the central elastic layer 1b is smaller than the outer diameter of the end elastic layer 11b, so that the central elastic layer 1b is placed outside the nip and the metal sleeve 1c. The heat release from the metal sleeve 1c to the central elastic layer 1b can be suppressed and the rise time can be shortened.

Next, a description will be given of a fourth embodiment of the fixing roller.
When the length of the fixing roller is the same as that of the pressure roller, the hardness of the pressure roller is higher than that of the fixing roller, and the fixing roller mainly deforms in the nip portion, the both ends of the fixing roller in the nip portion are It deforms as shown in FIG. Here, the fixing roller 1 according to the first embodiment will be described. As shown in FIG. 5, the end elastic layer 11b of the fixing roller 1 and the end surface of the elastic layer 2b of the pressure roller 2 swell outward in the axial direction. Is observed. That is, stress concentration occurs near the end faces of the fixing roller and the pressure roller. When the axial length of the metal sleeve 1c is the same as the axial length of the fixing roller elastic layer, the end of the sleeve is damaged or the sponge of the elastic layer breaks due to deformation by the nip and stress concentration at the end face. There is a fear.

  Therefore, in the fixing roller 30 of the fourth embodiment, as shown in FIG. 6, the axial length of the metal sleeve 1c is set in the axial direction of the fixing roller elastic layer (central elastic layer 1b + end elastic layer 11b × 2). It is configured to be smaller than the length. The rest of the configuration is the same as that of the fixing roller 1 of the first embodiment shown in FIG. In addition, the same code | symbol is attached | subjected to each part corresponded to the fixing roller 1 of 1st Example.

  In the fixing roller 30 of the fourth embodiment, since the length of the metal sleeve 1c is shorter than the length of the fixing roller (the length of the fixing roller elastic layer), the stress in the vicinity of the end surface of the elastic layer (end elastic layer 11b) It becomes difficult to receive concentration, and the life of the metal sleeve 1c can be extended. Further, as shown in the figure, in the configuration in which the length of the fixing roller (elastic layer) is smaller than the length of the elastic layer 2b of the pressure roller 2, the elastic layer end of the fixing roller 30 and the elastic layer of the pressure roller 2 are used. Since the positions of the end portions are not the same, the stress in the vicinity of the end surface of the fixing roller (sponge roller) is reduced, and the bubble breakage of the sponge roller (elastic layer) is reduced, so that the life of the fixing roller can be extended. Also in the fixing rollers of the second and third embodiments, the length of the metal sleeve 1c may be shorter than the length of the fixing roller elastic layer.

  In the fixing rollers of the first to fourth embodiments described above, the metal sleeve 1c and the sleeve movement preventing member 11 are bonded. However, a configuration in which the metal sleeve 1c and the sleeve movement preventing member 11 are not bonded is also possible. FIG. 7 is a cross-sectional view showing a fixing roller of a fifth embodiment which is a configuration example in which the metal sleeve and the sleeve movement preventing member are not bonded.

  In the fixing roller 40 of the fifth embodiment shown in FIG. 7, the sleeve movement preventing member 41 is obtained by laminating an elastic layer (end elastic layer) 41b on a perforated cored bar 41a. The end elastic layer 41 b has a small diameter portion 42 on the inner side in the axial direction and a large diameter portion 43 on the outer side. The inner small diameter portion 42 has an outer diameter slightly smaller than the inner diameter of the metal sleeve 1c, and is configured to have a slight gap from the sleeve inner surface. Thus, the sleeve movement preventing member 41 (the small diameter portion 42 thereof) can be easily fitted when fitted into the metal sleeve 1c. Further, the large-diameter portion 43 of the end elastic layer 41b restricts the movement of the sleeve movement preventing members 41, 41 with the retaining rings 7, 7 by inserting the sleeve movement preventing members 41, 41 into the fixing roller core 1a from both sides. By doing so, the large-diameter portion 43 of the end elastic layer can abut against the end surface of the metal sleeve 1c from both sides to press the sleeve, and the side of the metal sleeve 1c can be pressed to a certain range. Since the end elastic layer 41b (large-diameter portion 43) is an elastic member, even if the shift of the metal sleeve 1c cannot be completely eliminated, the movement (shift) is suppressed and the sleeve is suppressed to the extent that there is no hindrance. Can be prevented. In the configuration of this embodiment, the end elastic layer 41b (small diameter portion 42) is not bonded to the metal sleeve 1c, and heat escape from the metal sleeve 1c to the end elastic layer 41b can be reduced. . In addition, the deformation suppressing action of the metal layer due to adhesion does not occur, and it is possible to prevent a fixing failure due to the difficulty of forming a nip.

  FIG. 8 is a cross-sectional view showing a fixing roller of a sixth embodiment which is a configuration example in which the metal sleeve and the sleeve movement preventing member are not bonded. In the fixing roller 50 of the sixth embodiment shown in this figure, the end elastic layer 51b of the sleeve movement preventing member 51 has a small diameter portion 52 on the inner side in the axial direction and a large diameter portion 53 on the outer side in FIG. This is the same as the fixing roller 40. In the fixing roller 50 of this example, a plurality of convex portions 54 are provided on the small diameter portion 52, thereby providing a step on the small diameter portion. The rest is the same as the fixing roller 40 of the fifth embodiment. Since the small diameter portion 52 of the end elastic layer fitted to the inner surface of the metal sleeve 1c has a plurality of steps, the movement of the sleeve can be more effectively suppressed.

  As an example, with respect to the inner diameter of the metal sleeve 1c of 40.0 mm, the outer diameter of the small diameter portion 52 (the portion other than the convex portion 54) is 39.8 mm, and the outer diameter of the convex portion 54 portion is 40.2 mm. Alternatively, the outer diameter of the small diameter portion 52 (portion other than the convex portion 54) may be 40.2 mm, and the outer diameter of the convex portion 54 portion may be 40.5 mm, both of which may be larger than the sleeve inner diameter. In addition, the numerical value of an outer diameter is an example, Comprising: It does not restrict to what was illustrated.

  FIG. 9 is a cross-sectional view (a) and a plan view (b) showing a fixing roller of a seventh embodiment which is a configuration example in which the metal sleeve and the sleeve movement preventing member are not bonded. In the fixing roller 60 of the seventh embodiment shown in this figure, the end elastic layer 61b of the sleeve movement preventing member 61 has a small-diameter portion 62 on the inner side in the axial direction and a large-diameter portion 63 on the outer side. This is the same as the fixing roller 40. In the fixing roller 60 of this example, the small diameter portion 62 is provided with a plurality of convex portions 65 provided in the circumferential direction. Moreover, the hole 1d arranged in parallel with the circumferential direction is formed in the vicinity of the edge part of the metal sleeve 1c so that the convex part 65 may fit. The outer diameter of the convex portion 65 provided in the small diameter portion 62 of the end elastic layer 61b is provided to be substantially the same as the outer diameter of the sleeve so as to be fitted into the hole portion 1d of the metal sleeve 1c.

  In the seventh embodiment, the large diameter portion 63 of the end elastic layer 61b abuts on the end surface of the metal sleeve, and the convex portion 65 provided on the small diameter portion 62 is fitted into the hole 1d of the metal sleeve. Can be more effectively suppressed. The size and shape of the hole 1d and the protrusion 65 fitted to the hole 1d are arbitrary, but the axial length W of the hole 1d opened in the metal sleeve 1c is preferably about 1 to 5 mm. If it is smaller than 1 mm, the effect of suppressing the movement of the sleeve cannot be sufficiently obtained. On the other hand, if it is larger than 5 mm, the non-sheet-passing area is increased correspondingly, which causes an increase in size.

  FIG. 10 is a cross-sectional view showing a fixing roller of an eighth embodiment which is a configuration example in which the metal sleeve and the sleeve movement preventing member are not bonded. In the fixing roller 70 of the eighth embodiment shown in this figure, the sleeve movement preventing member 71 does not have a perforated cored bar, and a plurality of cylinders are formed on the inner peripheral surface of the elastic layer (end elastic layer) 71b. A pressing member 71a having a shape divided into four (in this example, divided into four equal parts) is attached. However, the number of pressing members 71a is not limited to four and is arbitrary. The sleeve movement preventing member 71 is inserted into the fixing roller core 1a and inserted into the end of the roller (in the inner periphery of the metal sleeve 1c) as shown in FIG. The outer diameter of the end elastic layer 71b is slightly smaller than the inner diameter of the metal sleeve 1c. In this state, there is a slight gap between the end elastic layer 71b and the inner surface of the metal sleeve. The movement preventing member 71 can be easily inserted inside the metal sleeve 1c. Then, the cylindrical pressure member 71c is fitted into the cored bar 1a and pushed into the inside of the pressing member 71a.

  The outer diameter of the pressing member 71c is larger than the inner diameter of the pressing member 71a (cylindrical inner diameter formed by the four pressing members 71a), and by pressing the pressing member 71c into the pressing member 71a, (B) As shown in the figure, the pressing member 71c spreads the end elastic layer 71b outward through the pressing member 71a, and presses the outer peripheral surface of the end elastic layer 71b against the inner peripheral surface of the metal sleeve 1c. . The sleeve movement preventing member 71 in a state where the pressing member 71c is pushed into the inside of the pressing member 71a is shown in the sectional view of FIG.

  In the eighth embodiment, when the end elastic layer 71b of the sleeve movement preventing member 71 is pressed against the inner peripheral surface of the metal sleeve 1c, a large braking force (sliding resistance) is generated, and the metal sleeve 1c is displaced. Can be reliably prevented. In addition, the amount of spread of the end elastic layer 71b is about 0.5 to 2 mm, and the movement of the metal sleeve can be sufficiently suppressed.

  Up to here, the fixing roller capable of restricting the shift of the metal layer (metal sleeve) in the axial direction has been described in each of the first to eighth embodiments, but a configuration example of a fixing device using the fixing roller of each of the above embodiments. Will be described.

  FIG. 12 is a sectional view schematically showing an example of a fixing device using the fixing roller according to the present invention. Here, the fixing roller 1 of the first embodiment is used for explanation, but a fixing roller of another embodiment can also be used. A fixing device 300 shown in FIG. 12 includes a fixing roller 1, a pressure roller 2, an induction heating device 3, and the like. The pressure roller 2 is pressed against the fixing roller 1 by a pressure mechanism (not shown), and a fixing nip is formed between the two rollers. An induction heating device 3 having a core 4 and a coil 5 is disposed on the outer periphery of the fixing roller 1 to heat the fixing roller 1 by eddy current due to electromagnetic induction. The recording medium P such as transfer paper carrying an unfixed toner image passes through a nip formed by the pressure roller 2 being pressed against the fixing roller 1, and the unfixed toner image is recorded on the recording medium P by heat and pressure. Fixed on top. By thinning the metal sleeve 1c, which is the heat generation layer of the fixing roller 1, and increasing the heat insulation of the elastic layer as much as possible, the heat capacity of the fixing roller can be reduced and the rise time can be shortened. Since the fixing roller 1 is restricted in the axial direction by the sleeve movement preventing member 11 as described above, it is possible to prevent the metal sleeve from being broken or the foam sponge from being broken as an elastic layer, and the fixing device has a long life. It has become. In addition, by obtaining a necessary nip, it is possible to obtain good fixability without causing fixing failure.

Finally, an application example of the present invention to an image forming apparatus will be described.
The image forming apparatus shown in FIG. 13 is a so-called tandem type intermediate transfer type full-color electrophotographic apparatus, which is configured as a copying apparatus including an image reading unit. The copying apparatus shown in this figure has an apparatus main body 310 mounted on a paper feed table 320, a scanner 330 is disposed at the top of the apparatus main body 310, and an automatic document feeder (ADF) 340 is further provided thereon. It is provided.

  The apparatus main body 310 is provided with an endless intermediate transfer belt 301 as an intermediate transfer member at the center. In the illustrated example, the intermediate transfer belt 301 is wound around three support rollers 302, 303, and 304 so as to be rotatable in the clockwise direction in FIG. Hereinafter, when the rotational movement of the belt is partially viewed, it is simply referred to as movement. An intermediate transfer belt cleaning device 305 for removing residual toner remaining on the intermediate transfer belt 301 after image transfer is provided to the left of the second support roller 303 among the three support rollers.

  Among the three support rollers, yellow (Y) and magenta (M) are arranged on the intermediate transfer belt 301 stretched between the first support roller 302 and the second support roller 303 along the moving direction. ), Cyan (C), and black (K), the four image forming units 311 are arranged side by side to constitute the tandem image forming unit 350. In this embodiment, the third support roller 304 is a drive roller. An exposure device 309 is further provided on the tandem image forming unit 350.

  On the other hand, a secondary transfer device 315 is provided on the opposite side of the intermediate transfer belt 301 from the tandem image forming unit 350. In the illustrated example, the secondary transfer device 315 includes a secondary transfer belt 316 that is an endless belt between two belt support rollers 317 and 318, and a third support roller via an intermediate transfer belt 301. The image on the intermediate transfer belt 301 is transferred to a sheet. Next to the secondary transfer device 315, a fixing device 300 that fixes an unfixed image transferred onto a sheet is disposed. The secondary transfer device 315 also has a paper transport function for transporting the paper after image transfer to the fixing device 300. Of course, a transfer roller or a non-contact charger may be disposed as the secondary transfer device. In such a case, it is necessary to separately provide a transport unit for transporting the sheet from the secondary transfer unit to the fixing device.

  The fixing device 300 is configured by pressing the pressure roller 2 against the fixing roller 1. The fixing device 300 is as described above with reference to FIG. Further, as the fixing roller, the fixing roller of each of the above embodiments can be employed.

  When taking a copy using this electrophotographic apparatus now, the original is set on the original table 341 of the automatic original feeder 340. Alternatively, the automatic document feeder 340 is opened, a document is set on the contact glass 331 of the scanner 330, and the automatic document feeder 340 is closed and pressed by it.

  When a start switch (not shown) is pressed, when a document is set on the automatic document feeder 340, the document is transported and moved onto the contact glass 331. On the other hand, when a document is set on the contact glass 331, the scanner 330 is immediately driven. Next, the first traveling body 332 and the second traveling body 333 travel. Then, the first traveling body 332 emits light from the light source, and the reflected light from the document surface is further reflected toward the second traveling body 333, reflected by the mirror of the second traveling body 333, and passed through the imaging lens 334. The document is placed in the reading sensor 335 and the content of the original is read.

  In parallel with document reading, the support roller 304 is driven to rotate by a drive motor (not shown), the other two support rollers are driven to rotate, and the intermediate transfer belt 301 is driven to rotate. At the same time, in each image forming unit 311, the photosensitive drum 312 is rotated, and each photosensitive drum 312 is exposed and developed using information for each color of yellow, magenta, cyan, and black to form a single color toner image. To do. As the intermediate transfer belt 301 moves, the single color toner images are sequentially transferred to form a composite color image on the intermediate transfer belt 301.

  On the other hand, in parallel with image formation, one of the paper feed rollers 321 of the paper feed table 320 is selectively rotated to feed the paper from one of the paper cassettes 323 provided in multiple stages in the paper bank 322, and the separation roller 324 1 Each sheet is separated and put into the paper feed path 325, transported by the transport roller 326, guided to the paper feed path in the copying machine main body 310, and abutted against the registration roller 328 and stopped. Alternatively, the paper feed roller 329 is rotated to feed out the paper on the manual feed tray 336, separated one by one by the separation roller 337, put into the manual paper feed path 338, and abutted against the registration roller 328 and stopped.

  Then, the registration roller 328 is rotated in synchronization with the composite color image on the intermediate transfer belt 301, the sheet is fed between the intermediate transfer belt 301 and the secondary transfer device 315, and is transferred by the secondary transfer device 315. Record a color image on paper.

  The paper after the image transfer is conveyed by the belt 316 and sent to the fixing device 300. The fixing device 300 applies heat and pressure to fix the transferred image, and then the switching paper is switched by the switching claw 339 and discharged by the discharge roller 342. , And stacked on the paper discharge tray 343. Alternatively, it is switched by the switching claw 339 and put into the sheet reversing unit 308, where it is reversed and guided again to the transfer position, and an image is recorded also on the back surface, and then discharged onto the paper discharge tray 343 by the discharge roller 342.

  On the other hand, the intermediate transfer belt 301 after the image transfer is removed by the intermediate transfer belt cleaning device 305 to remove residual toner remaining on the intermediate transfer belt 301 after the image transfer, and prepares for the image formation by the tandem image forming unit 350 again. In general, the registration roller 328 is often used while being grounded, but it is also possible to apply a bias for removing paper dust from the paper.

  It is possible to make a black and white copy using this electrophotographic apparatus. In that case, the intermediate transfer belt 301 is separated from the photosensitive drums 312Y, 312C, and 312M by means (not shown). These photosensitive drums are temporarily stopped from driving, and only the black photosensitive drum 312K contacts the intermediate transfer belt 301 to form and transfer an image.

  As mentioned above, although this invention was demonstrated by the example of illustration, this invention is not limited to this. For example, the axial length and diameter of the fixing roller can be set as appropriate. Further, the thickness of the metal sleeve as the heat generating layer is also arbitrary. In the fixing device, the pressure roller may be heated by a heat source.

  Further, the configuration of the image forming unit of the image forming apparatus is also arbitrary, and the arrangement order of the color image forming units in the tandem system is arbitrary. In addition to the tandem type, a configuration in which a plurality of developing devices are arranged around a single photosensitive member, or a configuration using a revolver type developing device is also possible. The present invention can also be applied to a full color machine using three color toners, a multicolor machine using two color toners, or a monochrome apparatus. Of course, the image forming apparatus is not limited to a copying machine, but may be a printer, a facsimile machine, or a multifunction machine having a plurality of functions.

1 is a cross-sectional view illustrating a first embodiment of a fixing roller according to the present invention. FIG. 5 is a schematic diagram illustrating a method for creating the fixing roller. FIG. 6 is a cross-sectional view illustrating a second embodiment of the fixing roller. FIG. 6 is a cross-sectional view illustrating a third embodiment of the fixing roller. It is a schematic diagram for demonstrating the stress concentration in a roller edge part. It is sectional drawing which shows the 4th Example of a fixing roller with a pressure roller. FIG. 10 is a cross-sectional view showing a fifth embodiment of the fixing roller. It is sectional drawing which shows the fixing roller of 6th Example. It is sectional drawing (a) and top view (b) which show the fixing roller of 7th Example. It is sectional drawing which shows the fixing roller of 8th Example. FIG. 6 is a cross-sectional view of a sleeve movement preventing member of the fixing roller. 1 is a cross-sectional view schematically showing an example of a fixing device using a fixing roller according to the present invention. 1 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus to which the present invention is applied. FIG. 10 is a cross-sectional view schematically illustrating an example of a conventional fixing device. FIG. 10 is a cross-sectional view illustrating a configuration example of a conventional fixing roller. It is a schematic diagram which shows the subject in the conventional fixing roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixing roller 1a Metal core 1b Center elastic layer 1c Metal sleeve 1d Hole 2 Pressure roller 6 Adhesive layer 7 Retaining ring 10, 20, 30, 40, 50, 60, 70 Fixing roller 11, 41, 51, 61, 71 Sleeve movement preventing member 11a, 41a Perforated core metal 11b, 41b, 51b, 61b, 71b End elastic layer 42 Small diameter portion 43 Large diameter portion 54, 65 Protruding portion 71a Press member 71c Pressure member 300 Fixing device

Claims (13)

In a fixing roller having an elastic layer at the center in the longitudinal direction of the roller and a metal sleeve provided outside the central elastic layer,
While disposing sleeve movement preventing members for restricting movement of the metal sleeve in the roller longitudinal direction on both sides of the central elastic layer in the roller longitudinal direction,
The fixing roller, wherein the sleeve movement preventing member has an elastic layer, and the elastic layer is an inner peripheral layer of the metal sleeve.   The fixing roller according to claim 1, wherein an outer peripheral portion of the elastic layer of the sleeve movement preventing member is bonded to the metal sleeve.   The fixing roller according to claim 1, wherein the hardness of the central elastic layer is greater than the hardness of the elastic layer of the sleeve movement preventing member.   4. The hardness of the elastic layer of the sleeve movement preventing member is 3 to 10 degrees, more preferably 5 to 8 degrees in Asuka C hardness, and is smaller than the hardness of the central elastic layer. The fixing roller described in 1.   The fixing roller according to claim 1, wherein the elastic layer of the sleeve movement preventing member is a solid rubber.   The outer diameter of the central elastic layer is smaller than the outer diameter of the elastic layer of the sleeve movement preventing member and smaller than the inner diameter of the metal sleeve. The fixing roller according to claim 1.   The length of the metal sleeve in the longitudinal direction of the roller is smaller than the length of the central elastic layer plus the length of the elastic layer of the sleeve movement preventing member on both sides of the central elastic layer. The fixing roller according to claim 1, wherein the fixing roller is a feature of the fixing roller.   2. The fixing roller according to claim 1, wherein the elastic layer of the sleeve movement preventing member has a large-diameter portion located outside the end surface of the metal sleeve and having a diameter larger than the outer diameter of the metal sleeve. .   The elastic layer of the sleeve movement preventing member has a plurality of convex portions projectingly contacted to the outer peripheral side at a portion located inside the metal sleeve, and the plurality of convex portions are engaged with the inner peripheral surface of the metal sleeve. The fixing roller according to claim 8, wherein the fixing roller is combined.   The elastic layer of the sleeve movement preventing member has a plurality of convex portions protruding in contact with the outer peripheral side at a portion located inside the metal sleeve and arranged in parallel in the circumferential direction, and near the end portion of the metal sleeve. The fixing roller according to claim 8, further comprising a plurality of holes into which the plurality of convex portions are fitted.   The sleeve movement preventing member includes outer diameter increasing means for increasing the outer diameter of the elastic layer of the sleeve movement preventing member, and the outer diameter increasing means causes the outer periphery of the elastic layer of the sleeve movement preventing member to be the inner periphery of the metal sleeve. The fixing roller according to claim 1, wherein the fixing roller is pressed.   A fixing device comprising the fixing roller according to claim 1.   An image forming apparatus comprising the fixing device according to claim 12.

Images