JP5071410B2 - Fixing device and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a fixing device and an image forming apparatus including the same.

  2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic method or an electrostatic recording method, a fixing device that fixes an unfixed image formed on a recording material such as recording paper by heating and pressing is used. Such a fixing device includes a heating roll having a heating source therein as a fixing rotator, and a pressure roll disposed so as to be in pressure contact with the heating roll, and a recording on which an unfixed image is formed. A configuration in which a medium is inserted between these fixing rotators and this unfixed image is fixed is widely adopted.

  Here, in patent document 1, the front-end | tip of the peeling member provided in the nip exit side of a heating roll and a pressure roll was made into the rounded shape, and the surface roughness Rz was 0.03-1.5 micrometers. A fixing device is disclosed.

JP 2006-313280 A

  An object of the present invention is to provide a fixing device capable of suppressing sticking of a recording material to a peeling member and an image forming apparatus provided with the same.

  The fixing device according to claim 1 is provided on a downstream side of the fixing rotator along a recording material conveyance direction, and a pair of fixing rotators which have a heating source at least one and face each other in pressure contact with each other. And a peeling member that peels off the recording material attached to the surface of the fixing rotating body. The peeling member is formed in a plate shape, and a plate-like base material is formed on a portion facing the recording material. And a resin layer formed on the substrate, the resin layer being formed on the outermost surface of the peeling member, having conductivity, and being grounded It is.

  A fixing device according to a second aspect is characterized in that, in the configuration according to the first aspect, the shape of the portion of the peeling member facing the recording material is uneven.

  According to a third aspect of the present invention, there is provided the fixing device according to the second aspect, wherein the irregularities are formed by forming irregularities on a layer below the resin layer, and coating the resin layer on a portion where the irregularities are formed. It is characterized by being.

  According to a fourth aspect of the present invention, there is provided the fixing device according to the second aspect, wherein the unevenness is formed by providing an uneven layer on a substrate and forming a resin layer thereon. It is characterized by.

  According to a fifth aspect of the present invention, there is provided the fixing device according to any one of the first to fourth aspects, wherein the resin layer is mainly composed of a fluororesin containing a filler. is there.

  A fixing device according to a sixth aspect is characterized in that, in the configuration according to the second aspect, the unevenness is provided with a height difference of 10 to 100 μm.

  According to a seventh aspect of the present invention, there is provided an image forming apparatus according to any one of the first to sixth aspects, a contact portion for grounding a resin layer of the fixing apparatus, and an image forming for forming an image on a recording material. Means.

  According to the first aspect of the present invention, even when the surface of the peeling member is formed of a resin layer, it is possible to prevent electrostatic adhesion accompanying charging during conveyance of the recording material.

  According to the second aspect of the present invention, it is possible to reduce the adhesion force accompanying the frictional force of the recording material to the peeling member.

  According to the third aspect of the present invention, it is possible to suppress the disturbance of the image due to the unevenness as compared with the case where the unevenness is formed on the resin layer itself.

  According to invention of Claim 4, the unevenness | corrugation of the surface can be easily formed by forming an unevenness | corrugation in a base material.

  According to the fifth aspect of the present invention, the releasability of the recording material with respect to the peeling member can be improved.

  According to the sixth aspect of the invention, it is possible to more effectively prevent the recording paper from adhering to the peeling member.

  According to the seventh aspect of the present invention, the resin layer of any one of the fixing devices can be easily grounded and can be suitably applied to an image forming apparatus.

1 is a configuration diagram showing a tandem type digital color copying machine as an example of an image forming apparatus to which the present invention is applicable. 2A and 2B are schematic diagrams for explaining a configuration of a fixing device according to the present embodiment, wherein FIG. 1A is a schematic side view, and FIG. 2B is a schematic diagram illustrating a surface pattern of a peeling baffle viewed from an arrow A direction. It is a figure, (c) is a schematic diagram which shows another pattern of the surface of a peeling baffle. It is an enlarged view of the schematic side surface for demonstrating the structure of the peeling baffle which concerns on this Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a schematic configuration of an image forming apparatus to which the present invention can be applied will be described with reference to FIG. Here, FIG. 1 is a configuration diagram showing a tandem type digital color copying machine as an example of an image forming apparatus to which the present invention is applicable.

  In FIG. 1, reference numeral 1 denotes a main body of a tandem type digital color copying machine as an example of an image forming apparatus to which the present invention can be applied. In a state where originals 2 are separated one by one at the upper part of the main body 1. An automatic document conveying device 3 that automatically conveys and a document reading device 4 that reads an image of the document 2 conveyed by the automatic document conveying device 3 are provided. The document reader 4 illuminates a document 2 placed on a platen glass 5 with a light source 6, and reflects a reflected light image from the document 2 from a full-rate mirror 7, half-rate mirrors 8 and 9, and an imaging lens 10. The image reading element 11 made of a CCD or the like is scanned and exposed through a reduction optical system, and the image material 11 reflects the color material reflected light image of the original 2 by a predetermined dot density (for example, 16 dots / mm). ).

  The color material reflected light image of the document 2 read by the document reading device 4 is subjected to image processing, for example, as document reflectance data of three colors of red (R), green (G), and blue (B) (8 bits each). The image processing apparatus 12 sends images such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color / moving editing, etc. to the reflectance data of the document 2. Processing is performed. In addition, the image processing device 12 performs predetermined image processing on image data sent from a personal computer or the like.

  The image data that has been subjected to the predetermined image processing by the image processing device 12 as described above is processed by the image processing device 12 in the same manner as yellow (Y), magenta (M), cyan (C), and black (K). (8 bits each) is converted into four-color original reproduction color material gradation data, and as described below, image formation of each color of yellow (Y), magenta (M), cyan (C), and black (K) The images are sent to the exposure devices 14 of the units 13Y, 13M, 13C, and 13K, and the exposure device 14 performs image exposure with the laser beam LB in accordance with the original reproduction color material gradation data of each color.

  Inside the tandem digital color copying machine main body 1, four image forming units 13Y, 13M, 13C, and 13K of yellow (Y), magenta (M), cyan (C), and black (K) are horizontally arranged. They are arranged in parallel at regular intervals in the direction.

  These four image forming units 13Y, 13M, 13C, and 13K are all configured in the same manner, and are roughly divided into a photosensitive drum 15 as an image carrier that is rotationally driven at a predetermined speed, and the photosensitive drum. A charging roll 16 for primary charging that uniformly charges the surface of 15, and an exposure device 14 including a scanning optical system that exposes an image corresponding to each color on the surface of the photosensitive drum 15 to form an electrostatic latent image, and The developing unit 17 develops the electrostatic latent image formed on the photosensitive drum 15 with each color toner (developer), and the drum cleaning unit 18 cleans the surface of the photosensitive drum 15.

  The exposure device 14 is configured in common to the four image forming units 13Y, 13M, 13C, and 13K, and modulates four semiconductor lasers (not shown) according to the original reproduction color material gradation data for each color, The laser beams LB-Y, LB-M, LB-C, and LB-K are emitted from the semiconductor laser according to the gradation data. Of course, the exposure apparatus 14 may be individually configured for each of a plurality of image forming units. The laser beams LB-Y, LB-M, LB-C, and LB-K emitted from the semiconductor laser are irradiated to the rotary polygon mirror 19 through an f-θ lens (not shown) and deflected by the rotary polygon mirror 19. Scanned. The laser beams LB-Y, LB-M, LB-C, and LB-K deflected and scanned by the rotary polygon mirror 19 are scanned and exposed from below on the photosensitive drum 15 through a plurality of reflection mirrors (not shown). Is done.

  The exposure apparatus 14 is hermetically sealed by a rectangular parallelepiped frame 20, and four laser beams LB-Y, LB-M, LB-C, and LB-K are placed on the upper portion of the frame 20. In order to perform exposure on the photosensitive drums 15 of the image forming units 13Y, 13M, 13C, and 13K, transparent glass windows 21Y, 21M, 21C, and 21K are provided as shield members. These glass windows 21Y, 21M, 21C, and 21K are members located at the uppermost position on the optical path along the laser beam LB of the exposure apparatus 14.

  From the image processing apparatus 12, an exposure apparatus 14 provided in common for the image forming units 13Y, 13M, 13C, and 13K for each color of yellow (Y), magenta (M), cyan (C), and black (K). In addition, the image data of each color is sequentially output, and the laser beams LB-Y, LB-M, LB-C, and LB-K emitted from the exposure device 14 according to the image data are the surfaces of the corresponding photosensitive drums 15. And an electrostatic latent image is formed. The electrostatic latent images formed on the photosensitive drum 15 are respectively yellow (Y), magenta (M), cyan (C), and black (K) toners by developing devices 17Y, 17M, 17C, and 17K. It is developed as an image (developer image).

  The yellow (Y), magenta (M), cyan (C), and black (K) toner images sequentially formed on the photosensitive drums 15 of the image forming units 13Y, 13M, 13C, and 13K are as follows. On the intermediate transfer belt 25 disposed over the image forming units 13Y, 13M, 13C, and 13K, the images are transferred in multiple by the primary transfer roll 26. The intermediate transfer belt 25 is wound around the drive roll 27 and the backup roll 28 with a constant tension, and is driven by a drive roll 27 that is rotationally driven by a dedicated drive motor with excellent constant speed (not shown). The circuit is circulated at a predetermined speed in the direction of the arrow. As the intermediate transfer belt 25, for example, a flexible synthetic resin film such as PET is formed in a band shape, and both ends of the synthetic resin film formed in a band shape are connected by means such as welding, thereby endless A belt-shaped one is used.

  The yellow (Y), magenta (M), cyan (C), and black (K) toner images transferred onto the intermediate transfer belt 25 in a multiple manner are transferred to the backup roll 28 by a secondary transfer roll 29. The recording paper P, which is secondarily transferred onto the recording paper P by the pressure contact force and electrostatic force, and onto which the toner images of these colors are transferred, is conveyed to the fixing device 30 positioned above. The secondary transfer roll 29 is in pressure contact with the side of the backup roll 28, and secondary-transfers each color toner image onto the recording paper P conveyed from below to above. The recording paper P on which the toner images of the respective colors are transferred is subjected to a fixing process with heat and pressure by the fixing device 30 and then discharged onto a discharge tray 33 provided on the upper portion of the main body 1 by a discharge roll 32. The

  The recording paper P having a predetermined size from the paper feed cassette 34 is once transported to a registration roll 38 via a paper transport path 37 by a paper feed roller 35 and a pair of rollers 36 for paper separation and transport. Stopped. The recording paper P supplied from the paper feed cassette 34 is sent to the secondary transfer position of the intermediate transfer belt 25 by a registration roll 38 that rotates at a predetermined timing.

  In the above-described digital color copying machine, when full-color double-sided copying is performed, the recording paper P with the image fixed on one side is not discharged onto the discharge tray 33 as it is by the discharge roll 32 but is switched not shown. The conveyance direction is switched by the gate, and the sheet is conveyed to the duplex conveyance unit 40 via the sheet conveyance roller pair 39. Then, in the double-sided conveyance unit 40, the recording paper P is conveyed again to the registration roll 38 with the front and back sides of the recording paper P reversed by a pair of conveyance rollers (not shown) provided along the conveyance path 41. Is discharged onto the discharge tray 33 after the image is transferred and fixed on the back surface of the recording paper P.

  The four image forming units 13Y, 13M, 13C, and 13K of yellow, magenta, cyan, and black are all configured in the same manner. In these four image forming units 13Y, 13M, 13C, and 13K, As described above, yellow, magenta, cyan, and black toner images are sequentially formed at predetermined timings. As described above, the image forming units 13Y, 13M, 13C, and 13K for the respective colors include the photosensitive drums 15, and the surfaces of these photosensitive drums 15 are uniformly charged by the charging roll 16 for primary charging. The Thereafter, the surface of the photosensitive drum 15 is scanned and exposed to an image forming laser beam LB emitted from the exposure device 14 according to the image data, and an electrostatic latent image corresponding to each color is formed. The laser beam LB scanned and exposed on the photosensitive drum 15 is set so as to be exposed at a predetermined inclination angle from an obliquely lower side slightly to the right side from directly below the photosensitive drum 15. The electrostatic latent images formed on the photosensitive drum 15 are respectively yellow, magenta, cyan, and black toners by the developing rolls 172 of the developing devices 17 of the image forming units 13Y, 13M, 13C, and 13K. Are developed into visible toner images, and these visible toner images are sequentially transferred onto the intermediate transfer belt 25 in multiple layers by charging of the primary transfer roll 26.

  Residual toner, paper dust, and the like are removed from the surface of the photosensitive drum 15 after the toner image transfer process by the drum cleaning device 18 to prepare for the next image forming process. The drum cleaning device 18 includes a cleaning blade 42 that removes residual toner, paper dust, and the like on the photosensitive drum 15. Further, residual toner, paper dust, and the like are removed from the surface of the intermediate transfer belt 25 after the toner image transfer process is completed by the belt cleaning device 43 to prepare for the next image forming process. The belt cleaning device 43 includes a cleaning brush 43a and a cleaning blade 43b. The cleaning brush 43a and the blade 42 remove residual toner, paper dust, and the like on the intermediate transfer belt 25.

  In the present embodiment, above the intermediate transfer belt 25, yellow (Y), magenta (M), cyan (C), and black (K) developing devices 17 having predetermined colors are provided. Toner cartridges 50Y, 50M, 50C, and 50K for supplying developer (mainly toner or toner containing carrier) are disposed.

  Next, the configuration of the fixing device 30 according to the present embodiment will be described with reference to FIG. Here, FIG. 2 is a schematic diagram showing a schematic configuration of the fixing device according to the present embodiment.

  As shown in FIG. 2, the fixing device 30 according to the present embodiment has a heating source inside, a heating roll 301 connected to a drive source (not shown) and formed to be rotatable, and the heating roll 301. And a pressure roll 303 that is press-contacted to the heating roll 301 at a predetermined pressure and is rotatably formed following the rotation of the heating roll 301, and the heating roll 301 is provided along the conveyance direction of the recording paper P. An inlet chute Gin for guiding the recording paper P on which an unfixed toner image is formed to the fixing device 30 is disposed on the upstream side (lower side in the drawing) of the nip portion N where the pressure roller 303 is in pressure contact with the fixing roller 30. Further, on the downstream side thereof, a separation member 310 that separates and conveys the recording sheet P after fixing from the fixing rotating body, and a conveyance guide of the recording sheet 18 separated by the separation member 310 are guided. Conveying guide member Gout in is arranged.

In the heating roll 301 in the present embodiment, for example, an elastic body layer made of silicone rubber or the like having a rubber hardness (JIS-A) of about 40 ° is coated around a metal core, and a PFA is further formed on the surface thereof. A surface layer made of a fluororesin layer such as a tube is formed, and a heating source 301H composed of, for example, two halogen lamps 301H ₁ and 301H ₂ is provided inside the core, and the surface temperature of the heating roll 301 is a predetermined level. The recording paper P on which an unfixed toner image is formed is heated by heating to a temperature. Further, a temperature sensor S that detects the surface temperature of the heating roll 301 in the sheet passing area of the recording paper P is disposed on one side surface (in this example, the right side surface in the drawing) of the heating roll 301.

  And when heating the heating roll 301, based on the detection result of the temperature sensor S, for example, the surface temperature of the heating roll 301 is turned on and off by turning on / off the power supply to the heating source 301H by an apparatus controller (not shown). Is heated to a predetermined temperature.

  Here, a halogen lamp, an IH induction heating device, or the like can be used as a heating source, but in this embodiment, a halogen lamp 301 is used. In addition, a belt, a film, a roll, or the like can be used as the fixing rotator, but in the present embodiment, a heating roll 301 and a pressure roll 303 are employed, and both are constituted by rolls. Further, when induction heating is employed as a heating source, the fixing rotator itself may be configured to generate heat.

  For example, the pressure roll 303 covers a metal core around an elastic body layer made of silicone rubber or the like having a rubber hardness (JIS-A) of about 40 °, and a fluororesin such as a PFA tube on the surface thereof. A surface layer composed of layers is formed and pressed against the heating roll 301 so that a predetermined pressing force is applied to the pressing area (nip area) N formed between the heating roll 301.

  A peeling baffle was used as the peeling member 310 according to this embodiment. The peeling baffle 310 is disposed on the downstream side of the nip portion N (in this example, disposed above the heating roll 301), and the portion 310t forming the conveyance path is not in contact with the surface of the heating roll 301. It is arranged to become.

  Although the present embodiment shows a case where there is only a peeling baffle as a configuration for peeling, a plurality of means may be used for peeling from the fixing rotating bodies 301 and 303. For example, a strong air flow is applied to the leading edge of the paper between the peeling baffle 310 and the fixing rotating bodies 301 and 303 shown in FIG. The peeling baffle 310 may be used as an auxiliary means for peeling so as to prevent it from being caught.

  Then, the recording paper P on which the unfixed image is formed is guided by the inlet chute Gin and is heated and pressurized while being inserted into the nip portion N to fix the image. Thereafter, the recording paper P that has passed through the nip portion N is It is peeled off from the surfaces of the fixing rotators 301 and 303 by the peeling baffle 310 and transported toward the discharge tray 33 and the like via the transport guide Gout.

  By the way, when the recording paper P is stuck to the peeling baffle 310 when the recording paper P is peeled from the fixing device 30 using the peeling baffle 310, the recording paper P is peeled off from the peeling baffle 310 and the fixing rotating bodies 301 and 303. It becomes a cause of troubles such as jams.

  Therefore, the peeling baffle 310 according to the present embodiment prevents the recording paper P from sticking as follows. Below, the structure of the peeling baffle 310 which concerns on this Embodiment is further demonstrated with reference to FIG. Here, FIG. 3 is a schematic enlarged view for explaining the configuration of the tip portion 310t of the peeling baffle 310 according to the present embodiment.

As schematically shown in FIG. 3, the peeling baffle 310 according to the present embodiment has a laminated structure at the tip portion 310 t. Specifically, the plate on the counter surface 310a ₁ facing the recording paper P of the base 310a of the (blade-like), are formed uneven layer 310b whose surface forms an uneven, further, the unevenness On the layer 310b, a conductive surface layer 310c coated with a resin so as to follow the uneven shape of the surface is laminated. Then, the peeling baffle 310 is neutralized by grounding the conductive surface layer 310c. Here, the plate shape is intended to exclude a peeling finger or the like.

  In the present embodiment, the unevenness of the surface layer 310c formed so as to follow the uneven layer 310b is set such that the height difference is 10 to 100 μm. Further, as shown in FIG. 2A, the shape may be uneven as a whole, or as shown in FIG. 2B, the shape is uneven only in the portion near the nip portion of the peeling member 310. May be formed.

  Here, the substrate 310a is not particularly limited in the present embodiment, but for example, a metal such as nickel, aluminum, iron, copper, or an alloy containing at least one of them (for example, stainless steel). ), Various resin materials such as polyesters such as polyethylene terephthalate, polyimide, polyamide, polymethyl methacrylate, polyacetal, and polyether ether ketone, and other various ceramic materials.

  As the surface layer (resin layer) 310c, a fluororesin (for example, PFA or PTFE) containing a conductive filler can be suitably used.

  As the filler, any conductive material can be used, and for example, carbon or the like can be used.

  As the concavo-convex layer 310b, the surface layer 310c is configured to have irregularities, the substrate 310a is processed by embossing or the like to form irregularities, or a member is attached to a part of the substrate 310a so as to form the projections An unevenness may be formed between the pasted member and the substrate 310a. In this embodiment, a glass cloth, which is a heat-resistant fabric, is inserted between the base material 310a and the surface layer 310c.

  In the peeling baffle 310 configured as described above, the contact area between the recording paper P and the peeling baffle 310 is reduced by the surface layer 310c formed so as to follow the shape of the uneven layer 310b and having a height difference of 10 to 100 μm. As a result, the contact resistance of the recording paper P with respect to the peeling baffle 310 can be reduced, and the mechanical adhesion accompanying the contact can be reduced.

In addition, the concavo-convex layer 310b can be easily formed by laminating (attaching) a woven fabric or the like originally having concavo-convex on the surface (opposite surface) 310a ₁ facing the recording paper P of the substrate 310a. By coating the surface of the concavo-convex layer 310b with a resin, it is possible to easily form the surface layer 310c having a desired roughness having gentle undulations.

  Further, by forming the surface layer 310c with a fluorine-based resin, a non-adhesive coating layer to which the melted toner hardly adheres is formed, and the releasability of the recording paper P with respect to the peeling baffle 310 can be improved.

  Furthermore, by grounding the peeling baffle 310 having the conductive surface layer 310c, the charge of the recording paper P charged due to friction or the like during conveyance is removed, and the recording paper P is electrostatically applied to the peeling baffle 310. It is possible to prevent adhesion.

  The technical scope of the present invention is not limited to the above-described embodiments, and various modifications or improvements can be added without departing from the scope of the present invention described in the claims. is there.

  For example, in the above-described embodiment, the configuration in which the peeling baffle 310 is provided on the heating roll 301 side is illustrated, but a similar peeling baffle 310 is also provided on the pressure roll 303 side to form a pair of peeling baffles 310 and 310. It may be configured. In addition, although a pair of roll-shaped fixing rotators are illustrated as the fixing rotator, one or both may be belt-shaped fixing rotators.

  Further, in the above-described embodiment, the configuration in which the uneven layer 310b formed of a woven fabric or the like is laminated on the surface of the base material 310a is illustrated, but the present invention is not limited to such a configuration, and the recording paper P It is only necessary to form irregularities having a predetermined roughness (a difference in height of 10 to 100 μm) on the surface layer 310c facing the surface. For example, it may be configured such that unevenness is directly formed on the surface of the base material 310a facing the recording paper P, and the surface is covered with a resin containing a filler.

1: Image forming apparatus, 13Y, 13M, 13C, 13K: Image forming unit, 14: Exposure apparatus, 15Y, 15M, 15C, 15K: Photosensitive drum, 16Y, 16M, 16C, 16K: Charging roll, 17Y, 17M, 17C , 17K: Development device, 18Y, 18M, 18C, 18K: Drum cleaning device, 25: Intermediate transfer belt, 26Y, 26M, 26C, 26K: Primary transfer roll, 29: Secondary transfer roll, 30: Fixing device, 34: Paper feeding cassette, 38: Registration roll, 40: Double-sided conveyance unit, 43: Belt cleaning device, 50Y, 50M, 50C, 50K: Toner cartridge, 301: Heating roll, 301H: Heating source, 303: Pressure roll, 310 : peeling baffle, 310a: base, 310a _1: opposing surfaces, 310b: uneven layer, 31 c: surface layer, 310t: tip, Gin: inlet chute, N: nip, P: recording sheet, S: a temperature sensor

Claims (7)

A pair of fixing rotators composed of a heating rotator having a heating source therein, and a pressure rotator driven in pressure contact with the heating rotator;
A peeling member provided on the downstream side of the fixing rotator along the conveyance direction of the recording material, and peeling the recording material stuck to the surface of the fixing rotator;
The peeling member is a peeling baffle disposed on the heating rotator in a non-contact manner on the heating rotator side,
The peeling baffle is formed in a plate shape, and has a plate-like non-conductive base material and a resin layer formed on the base material at a portion facing the recording material, A fixing device, wherein the fixing device is formed on an outermost surface of a peeling baffle and has conductivity , and the conductive resin layer is grounded. The heating rotator is arranged to be biased downward in the gravitational direction from the pressurizing rotator, and the recording material has a surface on which unfixed toner is fixed facing downward in the gravitational direction. The fixing device according to claim 1, wherein the fixing device is conveyed . The portion of the peeling member facing the recording material is provided with irregularities in the conveying direction and a direction orthogonal to the conveying direction, and the resin layer is continuously formed in the irregularities. Item 3. The fixing device according to Item 1 or 2 . The fixing device according to claim 3 , wherein the unevenness is formed by forming unevenness in a layer below the resin layer, and coating the resin layer on a portion where the unevenness is formed. The fixing device according to claim 3 , wherein the unevenness is formed by providing an uneven layer on a substrate and forming a resin layer thereon. 6. The fixing device according to claim 3 , wherein the unevenness is provided with a height difference of 10 to 100 [mu] m.   7. An image comprising: the fixing device according to claim 1; a contact portion for grounding a resin layer of the fixing device; and image forming means for forming an image on a recording material. Forming equipment.

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