JP2008164889A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the leakage of a lubricant from the ends part of a pressure belt coming into press contact with a heat roller, to reduce the wearing of a press-rubbing member, and to prevent the lubricant from sticking to a recording paper and to prevent soiling inside a device. <P>SOLUTION: The fixing device includes the pressure belt 41 that is rotated in press contact with at least one of a fixing member and the pressure member, the fixing device also includes: a lubricant application member 46 for applying the lubricant to the inside surface of the pressure belt 41; and at least a pair of first blade members 48 for scraping the lubricant while rubbing the inside surface at both ends of the pressure belt 41 in the width direction orthogonal to the rotating direction of the pressure belt 41. The lubricant scraped by the first blade members 48 is recovered to the lubricant application member 46. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an unfixed toner image formed on a transfer material, mounted on an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having these functions, by a fixing member and a pressure member. The present invention relates to a fixing device that fixes an image by applying pressure and heat, and an image forming apparatus including the fixing device.

  Conventionally, a fixing device used in an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine having these functions has a fixing roller maintained at a predetermined temperature and an elastic layer. A heat roller fixing system that presses and heats a transfer material on which an unfixed toner image is formed is sandwiched and conveyed by a fixing nip formed by a pressure roller that is in pressure contact with the fixing roller. Widely used from monochrome machines to color machines.

  The conventional heat roller fixing type fixing device is disadvantageous in terms of power saving because it is necessary to heat the fixing roller having a large heat capacity when heating the toner on the transfer material. There is a problem that it takes time to warm up, and the time until warming up (warm up time) becomes long.

  In recent years, a fixing belt has been used in the fixing device, the heat capacity has been reduced by the fixing belt, and the heat conduction efficiency has been greatly improved by bringing the temperature-controlled heater into direct pressure contact with the fixing belt, thereby substantially reducing power consumption and warm-up time. A belt-fixing type fixing device and an image forming apparatus which have a quick start that is not necessary have been proposed and recently used.

  In the above fixing device, since the fixing belt is pressed against the heating roller by the pressing member, if the friction between the inner surface of the fixing belt and the pressing member is large, traveling of the fixing belt is hindered, It causes fixing failure and paper wrinkles.

  For this reason, in the fixing device used in the conventional image forming apparatus, the inner surface of the fixing belt is lubricated to reduce the friction generated between the fixing belt and the pressure contact member and to allow the fixing belt to run smoothly. There is a configuration for supplying the agent.

  However, in this configuration, while the fixing process is repeated, the lubricant gradually moves to the end portion of the fixing belt, leaks from the end portion of the fixing belt, adheres to the recording paper, or damages the inside of the apparatus. The problem arises.

  In order to solve the above-described problem, a fixing device proposed in Patent Document 1 is provided on at least one of an outer peripheral surface of a belt guide member that rotatably supports both ends of a fixing belt and an inner peripheral surface of the fixing belt. Lubricant leakage prevention means is provided.

The fixing device proposed in Patent Document 2 is provided with a liquid-repellent processing part that repels a lubricant at both ends of an inner surface of a fixing belt.
JP 2002-357968 A JP 2004-191744 A

  However, in the fixing devices shown in Patent Document 1 and Patent Document 2, the lubricant that moves to the end of the fixing belt is pushed back to prevent lubricant leakage. The problem of enabling smooth running is not fully achieved.

  An object of the present invention is to prevent a lubricant from leaking from the end of a pressure belt and prevent the lubricant from adhering to a recording sheet and from fouling the inside of the apparatus. Another object of the present invention is to return the recovered lubricant to the lubricant application member and return it to the center of the pressure belt so that it can be circulated. It is another object of the present invention to prevent lubricant leakage at both axial ends of the support roller that supports the inner surface of the pressure belt.

  Accordingly, it is an object of the present invention to provide an image forming apparatus including a fixing device that forms a high-quality image while preventing the recording paper and the inside of the apparatus from being soiled.

  The above object can be achieved by the following solutions.

  1. In a fixing device having a pressure belt that rotates while being pressed against at least one of a fixing member and a pressure member, a lubricant application member that applies a lubricant to the inner surface of the pressure belt, and rotation of the pressure belt And at least a pair of first blade members that scrape and contact the inner surfaces of both end portions in the width direction orthogonal to the direction, and apply the lubricant to the lubricant scraped off by the first blade member. A fixing device characterized in that it is collected in a member.

  2. Image forming means for forming an image on an image carrier, paper feeding means for supplying a recording medium to the image forming means, transfer means for transferring the image to the recording medium, and the recording to which the image has been transferred An image forming apparatus comprising: the fixing device according to 1 above, which fixes a medium.

  The fixing device and the image forming apparatus of the present invention can obtain the following effects by the configuration described above.

  1. By scraping off the lubricant at the end of the inner surface of the fixing belt with a blade, leakage of the lubricant from the end of the fixing belt is prevented, and the lubricant is prevented from adhering to the recording paper or fouling the inside of the apparatus. Is done. In addition, the configuration in which the lubricant scraped off by the blade is returned to the lubricant application member enables the lubricant to be returned to the center of the pressure belt for circulation and stable lubricant application for a long period of time. become. Further, the durability of the pressure belt due to wear of the pressure sliding contact member on the inner surface of the pressure belt and the deterioration of the lubricant due to the abrasion powder are prevented.

  2. An image forming apparatus including a fixing device that forms a high-quality image by preventing recording paper and the inside of the apparatus from being damaged is provided.

  Embodiments of the present invention will be described below. The description in this column does not limit the technical scope of the claims or the meaning of terms.

[Image forming apparatus]
FIG. 1 is a configuration diagram of an image forming apparatus according to the present invention.

  The image forming apparatus A is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, a transfer material feeding / conveying unit, and a fixing device 30.

  The document placed on the document table is scanned and exposed by the optical system of the document image scanning exposure device of the image reading device SC, read into the line image sensor, and the analog signal subjected to photoelectric conversion is received by the image processing unit. After analog processing, A / D conversion, shading correction, image compression processing, etc., the data is input to the optical writing means 3Y, 3M, 3C, 3K.

  An image forming unit 10Y that forms a yellow (Y) image includes a charging unit 2Y, an optical writing unit 3Y, a developing device 4Y, and a cleaning unit 5Y disposed around the image carrier 1Y. An image forming unit 10M that forms a magenta (M) color image includes an image carrier 1M, a charging unit 2M, an optical writing unit 3M, a developing device 4M, and a cleaning unit 5M. An image forming unit 10C for forming a cyan (C) color image includes an image carrier 1C, a charging unit 2C, an optical writing unit 3C, a developing device 4C, and a cleaning unit 5C. An image forming unit 10K that forms a black (K) image includes an image carrier 1K, a charging unit 2K, an optical writing unit 3K, a developing device 4K, and a cleaning unit 5K.

  The charging unit 2Y and the optical writing unit 3Y, the charging unit 2M and the optical writing unit 3M, the charging unit 2C and the optical writing unit 3C, and the charging unit 2K and the optical writing unit 3K constitute a latent image forming unit.

  4Y, 4M, 4C, and 4K are developing devices that contain a two-component developer composed of a small particle size toner of yellow (Y), magenta (M), cyan (C), and black (K) and a carrier.

  The intermediate transfer body 6 is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred onto the rotating intermediate transfer body 6 by the primary transfer units 7Y, 7M, 7C, and 7K, and a combined color image is formed. It is formed.

  The recording paper S accommodated in the paper feed cassette 20 is fed by a paper feed unit (first paper feed unit) 21 and conveyed to a secondary transfer unit 7A via a registration roller (second paper feed unit) 22. Then, a color image is transferred onto the recording paper S. The recording paper S to which the color image has been transferred is sandwiched by the fixing device 30, and the toner image on the recording paper S is fixed by applying heat and pressure, and is discharged outside the apparatus.

  On the other hand, after the color image is transferred to the recording paper S by the secondary transfer means 7A, the residual toner is removed by the cleaning means 8 from the intermediate transfer body 6 from which the recording paper S has been separated.

  The operation display unit 11 installed in the upper part of the main body of the image forming apparatus A has a transfer material selection setting unit, and sets various recording sheets S such as plain paper and coated paper. Further, the thickness (basis weight) of the recording sheet S, the size, the number of sheets, and the like of the recording sheet S are set.

  Further, near the upper part of the main body of the image forming apparatus A, there are a main power switch for turning on and off the main power source 12 for executing the image forming process, and a sub power source switch for turning on and off the sub power source 13 for executing the power saving mode. Is arranged. In the main body of the image forming apparatus A, a control unit 14 that controls the fixing device 30 and a storage unit 15 that stores the on / off states of the main power supply 12 and the sub power supply 13 are arranged.

  In the description of the image forming apparatus A, the color image formation has been described. However, the present invention includes a case of forming a monochrome image.

[Fixing device]
FIG. 2 is a cross-sectional view of the fixing device 30 according to the present invention. FIG. 3 is an enlarged cross-sectional view in the vicinity of the pressure belt 41.

  The fixing device 30 according to the present invention includes a heating unit 300 above the sheet passing path and a pressure unit 400 below the sheet passing path. The heating unit 300 includes a heating roller (fixing member) 31 and the like. The pressure unit 400 includes a pressure belt 41 and the like.

  A single color toner image or a multicolor toner image on the recording paper S is fixed by heating and pressing through a fixing nip formed between the heating roller 31 and the pressure belt 41.

  Two heating sources 32 are arranged inside the heating roller 31, and two external heating sources 33 are arranged on the outer peripheral surface of the heating roller 31. On the outer peripheral surface of the heating roller 31, a lubricant supply means 34, a cleaning means 35, a separation claw 36, a temperature sensor (not shown), and the like are arranged. The cleaning means 35 includes a web former winding portion 351, a web winding portion 352, a web pressing roller 353, a cleaning roller 354, a cleaning web 355, and the like.

  The pressure belt 41 is wound around each outer periphery of a support roller (hereinafter referred to as an entrance roller) 42 near the introduction portion of the recording paper S, a separation roller 43 near the exit portion of the recording paper S, and a tension roller 44. Then, it contacts the outer peripheral surface of the heating roller 31.

  The pressing / sliding contact member (pad) 45 presses the inner surface side of the pressure belt 41 stretched between the inlet roller 42 and the separation roller 43 so as to press-contact the outer peripheral surface of the heating roller 31. The surface layer of the inner surface end portion of the pressure belt 41 is covered with a fluororesin layer. By covering the surface layer with a fluororesin layer, the wettability to the lubricant is reduced and the oil film is difficult to be formed. .

  On the inner surface side of the pressure belt 41, a lubricant application member 46, a first blade member 48, and a second blade member 49 are disposed between the pressure sliding contact member 45 and the entrance roller 42. Are formed in an integrated unit. By integrating these members, the lubricant recovery path can be made compact. In addition, maintenance for unit replacement can be performed at the same time.

  The separation claw 51 abuts on the outer peripheral surface of the pressure belt 41 around which the separation roller 43 is wound, and separates the leading end portion of the recording paper S from the pressure belt 41.

  The pressing unit 52 holds the pressing unit 400 having the pressing belt 41 and the like so as to be movable up and down, and presses the pressing belt 41 against the heating roller 31.

  The lubricant application member 46 is formed of a nonwoven fabric such as an aramid fiber. The lubricant application member 46 is formed by bending a piece of nonwoven fabric and joining the end portions thereof, and forming the lower portion in a bag shape. The bent portion abuts against the inner surface of the pressure belt 41.

  A foam material 47 such as felt or a silicone rubber foaming agent is inserted into the bag-like portion at the bottom of the lubricant application member 46. The lubricant application member 46 and the foam material 47 are impregnated with a lubricant in advance.

  Both sides of the intermediate portion of the lubricant application member 46 are supported by support members 48A and 49A such as stainless steel plates.

  The first blade member 48 is bonded to the outside of the support member 48A with an adhesive. The tip of the first blade member 48 is in pressure contact with the vicinity of both ends on the inner surface side of the pressure belt 41 at a position downstream of the tip of the lubricant application member 46 in the rotation direction of the pressure belt 41. The tip of the first blade member 48 presses the inner surface side of the pressure belt 41 in a counter form, and scrapes off the lubricant adhering to the inner surface side of the pressure belt 41.

  The second blade member 49 is bonded to the outside of the support member 49A with an adhesive. The tip of the second blade member 49 is pressed against the shaft end 42A in the vicinity of both ends of the inlet roller 42 in a counter form, and scrapes off the lubricant adhering to the shaft end 42A.

  The surfaces of the first blade member 48, the second blade member 49, and the shaft end portion 42A in the vicinity of both end portions of the entrance roller 42 are covered with a fluororesin layer.

  The lubricant scraped from the vicinity of both ends of the inner surface of the pressure belt 41 by the tip of the first blade member 48 descends along the surface of the first blade member 48 and foams in the lubricant application member 46. It is absorbed by the material 47 and recycled. Further, the lubricant scraped off from the shaft end portions 42A at both ends of the entrance roller 42 by the tip end portion of the second blade member 49 descends along the surface of the second blade member 49, and the lubricant application member It is absorbed by the foam material 47 in 46 and used in circulation.

  FIG. 4 is a schematic diagram of the pressurizing unit 400.

  The inner width of the pair of first blade members 48 that are in sliding contact with both ends on the inner surface of the pressure belt 41 is B1i, and the outer width is B1o. The width of the pressure sliding contact member 45 is P, the length in the axial direction of the support portion of the entrance roller 42 is W, the average diameter of the pressure belt support portion of the entrance roller 42 is R, and the lubricant application width of the lubricant application member 46 is Let L be.

  (1) Set B1i> P. When the width P of the press sliding contact member 45 is larger than the inner distance of the first blade member 48 B1i (B1i> P), the wear of the press sliding contact member 45 becomes intense at the portion where the lubricant is scraped off.

  (2) Set W> B1i + R / 3. The lubricant is pushed and spread at the contact portion of the pressure belt 41 with the entrance roller 42 and pushed out to both ends of the inner surface of the pressure belt 41. In order to prevent this, the length W in the axial direction of the pressure belt support portion of the entrance roller 42 is made larger than B1i + R / 3, and the lubricant moves to the vicinity of both ends of the entrance roller 42 and leaks to the outside. To prevent.

  (3) Set B1o> W + R / 3. Lubricant is spread over the end of the pressure belt 41 supporting portion of the inlet roller 42 and further leaks to the outside. In order to scrape off this lubricant, the outer distance between the two first blade members 48 is set to be larger than W + R / 3 with respect to the axial length W of the entrance roller 42 (B1o> W + R / 3). Greatly prevents lubricant leakage.

  (4) L <W−R / 3 is set. The lubricant application width L of the lubricant application member 46 is shorter than the axial length W of the entrance roller 42. For example, when the average diameter R of the entrance roller 42 is set, L <W−R / 3 is set. When the lubricant application width L by the lubricant application member 46 is equal to or greater than the axial length W of the pressure belt support portion of the inlet roller 42, the lubricant is brought into contact with the pressure belt 41 and the inlet roller 42. Is spread and seeps. Therefore, by making the lubricant application width L smaller than the width W of the entrance roller 42 by R / 3, the seepage of the lubricant can be suppressed.

  (5) The first blade member 48 has a greater leakage prevention effect when the width is wider, but the first blade exceeding about 10 mm at both ends of the pressure belt 41 has a large runaway of the belt surface during rotation. The member cannot follow the movement of the belt surface.

  At least one pair of the first blade member 48 and the second blade member 49 is disposed at both ends in the width direction orthogonal to the rotation direction of the pressure belt 41.

  Both the outer width B1o of the first blade member 48 and the outer width B2 of the second blade member 49 were set to be smaller than the width B3 of the pressure belt 41. As a result, the lubricant that has been scraped off by the outer side of the first blade member 48 and the second blade member 49 and leaked to the outside flows from the end of the pressure belt 41 toward the outer peripheral surface and adheres to the recording paper S. And the inside of the device is prevented from being soiled.

  The pressure belt 41 travels with slight deformation at both ends in the width direction where it does not contact the entrance roller 42. By providing the first blade member 48 with a cut and dividing it into a plurality of tongue-like shapes, the front end portion of the first blade member 48 is in uniform contact with the inner peripheral surface of the pressure belt 41 and the lubricant. Prevent leakage.

  FIG. 5 is a view showing the shape of the tip of the first blade member 48.

  The shape of the tip part of the pair of first blade members 48 forms an inclined surface having an inner side with an inclination angle θ shorter than the outer side with respect to the direction orthogonal to the rotation direction of the pressure belt 41. . The inclination angle θ is set to 4 ° or more and less than 16 °. The leading edge of the outer portion of the first blade member 48 is in sliding contact with the inner surface in the vicinity of both end portions in the width direction of the pressure belt 41.

  By setting the inclined surface θ to an inclined surface having an angle of 4 ° or more, an effect of attracting the lubricant to the center is generated, and leakage of the lubricant can be prevented. When the inclined surface has an inclined angle θ of 16 ° or more, it is difficult to bring the first blade member 48 into close contact with the entire pressure belt 41, and the effect of preventing lubricant leakage is reduced.

  Note that the pressure unit 400 of the present invention can also be applied to a fixing device having a configuration in which a fixing belt having a heating source is disposed in place of the heating roller 31.

1 is a configuration diagram of an image forming apparatus according to the present invention. 1 is a cross-sectional view of a fixing device according to the present invention. FIG. 3 is an enlarged sectional view in the vicinity of a pressure belt. The schematic diagram of a pressurizing means. The figure which shows the front-end | tip part shape of a 1st blade member.

Explanation of symbols

30 Fixing device 300 Heating means 31 Heating roller (fixing member)
400 Pressure means 41 Pressure belt (pressure member)
42 Support roller (entrance roller)
42A Shaft end 45 Press sliding contact member (pad)
46 Lubricant application member 47 Foam material 48 First blade member 48A, 49A Support member 49 Second blade member

Claims (11)

In a fixing device having a pressure belt that rotates while being pressed against at least one of a fixing member or a pressure member,
A lubricant application member for applying a lubricant to the inner surface of the pressure belt;
And at least a pair of first blade members that slidably contact the inner surfaces of both ends in the width direction perpendicular to the rotation direction of the pressure belt and scrape the lubricant.
A fixing device, wherein the lubricant scraped off by the first blade member is collected in the lubricant application member. At least scraping off the lubricant adhering to the support roller in contact with an end portion orthogonal to the rotation direction of a support roller that is disposed in the vicinity of the first blade member and rotatably supports the pressure belt. A pair of second blade members;
The fixing device according to claim 1, wherein the lubricant scraped off by the second blade member is collected in the lubricant application member. The inner width B1i of the first blade member, the outer width B1o of the first blade member, the width P of the pressing sliding contact member, the axial length W of the pressure belt support portion of the support roller, and the addition of the support roller The fixing device according to claim 1, wherein an average diameter R of the pressure belt support portion and a lubricant application width L of the lubricant application member are set so as to satisfy the following formula.
B1i> P
W> B1i + R / 3
B1o> W + R / 3
L <W−R / 3 The fixing device according to claim 1, wherein an outer width of the first blade member and an outer width of the second blade member are both smaller than a width of the pressure belt. 2. The fixing device according to claim 1, wherein at least one pair of the first blade member and the second blade member is disposed at both ends in a width direction orthogonal to a rotation direction of the pressure belt. . The said 1st blade member, the said lubricant application member, and the said 2nd blade member were formed in the integral cleaning unit, and it was made to replace | exchange, The any one of Claim 1 thru | or 5 characterized by the above-mentioned. Fixing device. 6. The fixing device according to claim 1, wherein a front end portion of the first blade member is in sliding contact with an inner surface of the pressure belt in a counter form. 8. The fixing device according to claim 1, wherein a tip end portion of the second blade member is in sliding contact with both ends of the support roller in a counter form. 9. The shape of the tip part of the pair of first blade members has an inclined surface of 4 ° or more and less than 16 ° whose inner part in the direction orthogonal to the rotation direction of the pressure belt is shorter than the outer part,
The fixing device according to claim 1, wherein a leading edge of the outer portion is in sliding contact with inner surfaces in the vicinity of both end portions in the width direction of the pressure belt. At least one surface layer of the tip portion of the first blade member, the tip portion of the second blade member, the inner surface end portion of the pressure belt, and the axial end portion of the support roller is covered with a fluororesin layer. The fixing device according to claim 1, wherein the fixing device is a fixing device. Image forming means for forming an image on an image carrier, paper feeding means for supplying a recording medium to the image forming means, transfer means for transferring the image to the recording medium, and the recording to which the image has been transferred An image forming apparatus comprising: the fixing device according to claim 1 for fixing a medium.

Images