This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2011-151091 filed Jul. 7, 2011.
(i) Technical Field
The present invention relates to an applying device, a fixing device, and an image forming apparatus.
According to an aspect of the invention, there is provided an applying device including an applying member that applies an applying material to an outer peripheral surface of a fixing member that rotates, while a peripheral velocity difference is caused to exist between a peripheral velocity of the fixing member and a peripheral velocity of the applying member. The applying material contains a fluorocarbon resin material.
Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein:
An exemplary applying device, an exemplary fixing device, and an exemplary image forming apparatus according to a first exemplary embodiment of the present invention will be described.
The sheet holding section 12 includes a first holding section 22, a second holding section 24, and a third holding section 26, which hold pieces of recording paper P having different sizes. Delivery rollers 32 that deliver the held pieces of recording paper P into a transport path 28 provided in the image forming apparatus 10 are provided at the first holding section 22, the second holding section 24, and the third holding section 26. Pairs of transport rollers 34 and pairs of transport rollers 36 that transport the pieces of recording paper P one at a time are provided downstream from the delivery rollers 32 in the transport path 28. Aligning rollers 38 that temporarily stop the pieces of recording paper P and that deliver the pieces of recording paper P to a second transfer position QB (described later; see
As viewed from the front of the image forming apparatus 10, an upstream-side portion (that is, a portion where the transport rollers 36 are provided) of the transport path 28 is linearly provided from the left side of the sheet holding section 12 to a lower portion of the left side of the image forming section 14 in the direction of arrow V. A downstream-side portion of the transport path 28 is provided from the lower portion of the left side of the image forming section 14 up to a sheet-discharge section 15 provided on the right side of the image forming section 14. A two-side transport path 29 that transports and reverses a piece of recording paper P for forming images on both sides of the piece of recording paper P is connected to the transport path 28.
As seen from the front of the image forming apparatus 10, the two-side transport path 29 is provided with a first switching member 31, a reversing section 33, a transport section 37, and a second switching member 35. The first switching member 31 switches between the transport path 28 and the two-side transport path 29. The reversing section 33 is linearly provided from a lower portion of the right side of the image forming section 14 to the right side of the sheet holding section 12 in the direction of arrow V (a downward direction is indicated by −V and an upward direction is indicated by +V in the
The first switching member 31 is a triangular columnar member. When an end portion of the first switching member 31 is moved to either one of the transport path 28 and the two-side transport path 29 by a driving unit (not shown), the first switching member 31 switches the direction of transport of the recording paper P. The second switching member 35 is similarly a triangular columnar member when viewed from the front side. When an end portion of the second switching member 35 is moved to either one of the reversing section 33 and the transport section 37 by a driving unit (not shown), the second switching member 35 switches the direction of transport of the recording paper P. A downstream-side end portion of the transport section 37 is connected to a near side of the transport rollers 36, disposed at the upstream-side portion of the transport path 28, by a guide member (now shown). A folding manual paper feed section 46 is provided at a left surface of the image forming section 14. A transport path of a piece of recording paper P that is transported from the manual paper feed section 46 is connected to a near side (upstream side) of the aligning rollers 38 at the transport path 28.
The document reading section 16 includes a document transport device 52, a platen glass 54, and a document reading device 56. The document transport device 52 automatically transports reading documents G one at a time. The platen glass 54 is disposed at a lower side of the document transport device 52. One reading document G is placed on the platen glass 54. The document reading device 56 reads a reading document G transported by the document transport device 52, or a reading document G placed on the platen glass 54.
The document transport device 52 includes an automatic transport path 55 in which pairs of transport rollers 53 are disposed. A portion of the automatic transport path 55 is disposed so that a piece of recording paper P passes above the platen glass 54. The document reading device 56 reads a reading document G transported by the document transport device 52 while being stationary at a left end portion of the platen glass 54, and reads a reading document G placed on the platen glass 54 while moving in the direction of arrow H.
The image forming section 14 includes an image forming unit 50 serving as an exemplary developer image forming unit that forms a toner image (developer image) on a piece of recording paper P. The image forming unit 50 includes a photoconductor member 62, a charging member 64, an exposure device 66, a developing device 70, an intermediate transfer belt 68, and a cleaning device 73, which are described below.
The cylindrical photoconductor member 62 serving as a latent image holding member is provided at the center of the apparatus body 10A in the image forming section 14. The photoconductor member 62 is rotated in the direction of arrow +R (counterclockwise in
The exposure device 66 is provided at a location that is situated downstream from the charging member 64 in a direction of rotation of the photoconductor member 62 and that opposes the outer peripheral surface of the photoconductor member 62. The exposure device 66 includes a semiconductor laser, a f-θ lens, a polygonal mirror, an imaging lens, and mirrors (none of which are shown). On the basis of an image signal, laser light emitted from the semiconductor laser is used to perform scanning by being deflected by the polygonal mirror, and illuminates (exposes) the outer peripheral surface of the photoconductor member 62 charged by the charging member 64, to form an electrostatic latent image. The exposure device 66 may be a light emitting diode (LED) type instead of a type in which laser light is used to perform scanning by being deflected by the polygonal mirror.
The developing device 70 of a rotation switching type is provided at a location opposing a portion that is situated downstream from a portion of the photoconductor member 62 that is irradiated with exposure light from the exposure device 66 in the direction of rotation of the photoconductor member 62. The developing device 70 develops the electrostatic latent image formed on the outer peripheral surface of the photoconductor member 62 with toner of a set color to make the electrostatic latent image visible.
As shown in
Since the developing units 72Y, 72M, 72C, and 72K, have the same structure, the developing unit 72Y will be described here, and the other developing units 72M, 72C, and 72K will not be described.
The developing unit 72Y includes a case member 76 serving as a body. The interior of the case member 76 is filled with a developer (not shown) containing toner and carriers supplied from a toner cartridge 78Y (see
The development roller 74 includes a rotatable cylindrical development sleeve 74A and a magnetic member 74B including magnetic poles and secured to the inner side of the development sleeve 74A. By rotating the development sleeve 74A, a magnetic brush of a developer (carrier) is formed. In addition, by regulating the thickness of the layer of the developer by the regulating member 79, the developer layer is formed on an outer peripheral surface of the development sleeve 74A. The developer layer on the outer peripheral surface of the development sleeve 74A is transported to a location opposing the photoconductor member 62 by rotating the development sleeve 74A, so that toner corresponding to the latent image (electrostatic latent image) formed on the outer peripheral surface of the photoconductor member 62 is caused to adhere to the latent image, thereby developing the latent image.
Two rotatable spiral transport rollers 77 are disposed side by side in the case member 76. By rotating the two transport rollers 77, the developer with which the interior of the case member 76 is filled is circulated and transported in an axial direction of the development roller 74 (that is, in a longitudinal direction of the developing unit 72Y). Four development rollers 74 provided at the corresponding developing units 72Y, 72M, 72C, and 72K are disposed in the peripheral direction so that development rollers 74 that are adjacent to each other are spaced apart by a central angle of 90 degrees. By switching a certain developing unit 72, a next development roller 74 is caused to oppose the outer peripheral surface of the photoconductor member 62.
As shown in
A first transfer roller 67 that first-transfers a toner image formed on the outer peripheral surface of the photoconductor member 62 to the intermediate transfer belt 68 is provided opposite the photoconductor member 62 with the intermediate transfer belt 68 being interposed therebetween. The first transfer roller 67 contacts the inner surface of the intermediate transfer belt 68 at a location that is spaced apart and downstream in the direction of movement of the intermediate transfer belt 68 from a position where the photoconductor member 62 and the intermediate transfer belt 68 contact each other (this position is called a first transfer position QA (see
A second transfer roller 71 serving as an exemplary transfer unit that second-transfers the toner image first-transferred to the intermediate transfer belt 68 to a piece of recording paper P is provided opposite the auxiliary roller 69 with the intermediate transfer belt 68 being interposed therebetween. A position between the second transfer roller 71 and the auxiliary roller 69 is the second transfer position QB where the toner image is transferred to the piece of recording paper P. The second transfer roller 71 is connected to ground and contacts an outer surface of the intermediate transfer belt 68. Due to a potential difference between the second transfer roller 71 and the auxiliary roller 69 to which current is applied from a power supply (not shown), the second transfer roller 71 causes the toner image on the intermediate transfer belt 68 to be second-transferred to the piece of recording paper P. The second transfer position QB is set in the transport path 28 (see
A cleaning blade 59 that collects residual toner remaining after the second transfer on the intermediate transfer belt 68 is provided opposite the driving roller 61 with the intermediate transfer belt 68 being interposed therebetween. The cleaning blade 59 is mounted to a housing (not shown) having an opening. The toner scraped off by an end portion of the cleaning blade 59 is collected in the housing.
A position detecting sensor 83 is provided at a position opposing one of the transport rollers 63 in the vicinity of the intermediate transfer belt 68. The position detecting sensor 83 detects a mark (not shown) on the surface of the intermediate transfer belt 68 to detect a predetermined reference position on the intermediate transfer belt 68, and outputs a position detection signal serving as a reference of a timing of starting an image forming operation. The position detecting sensor 83 illuminates the intermediate transfer belt 68 with light, and receives the light reflected from the surface of the mark, to detect the position of movement of the intermediate transfer belt 68.
A cleaning device 73 that cleans off, for example, residual toner remaining on the surface of the photoconductor member 62 without being first-transferred to the intermediate transfer belt 68 is provided downstream from the first transfer roller 67 in the direction of rotation of the photoconductor member 62. The cleaning device 73 is formed so that, for example, residual toner is collected by a cleaning blade 73A and a brush roller 73B that contact the surface of the photoconductor member 62.
A corotron 81 that removes electricity from the toner remaining after the first transfer on the outer peripheral surface of the photoconductor member 62 is provided upstream from the cleaning device 73 (that is, downstream from the first transfer roller 67) in the direction of rotation of the photoconductor member 62. Further, an electricity removing device 75 that removes electricity by irradiating the outer peripheral surface of the photoconductor member 62 with light after the cleaning is provided downstream from the cleaning device 73 (that is, upstream from the charging member 64) in the direction of rotation of the photoconductor member 62.
As shown in
The toner cartridge 78Y and toner cartridges 78M, 78C, and 78K that contain toners of corresponding colors, yellow (Y), magenta (M), cyan (C), and black (K), are replaceably provided side by side in the direction of arrow H and above the developing device 70 that is situated below the document reading device 56.
Next, the fixing device 100 will be described.
As shown in
An external heating roller 108, a retracting mechanical section 140 (see
The fixing roller 102 is disposed at a toner image surface side (upper side) of the recording paper P at the transport path. In an example of the fixing roller 102, as shown in
As shown in
The external heating roller 108, the cleaning roller 120, an applying roller 112 serving as an exemplary applying member, and a first temperature sensor 132 are provided at positions opposing the outer peripheral surface of the fixing roller 102 in that order from an upstream side towards a downstream side in the direction of rotation of the fixing roller 102. The applying roller 112 applies the applying material 112B (see
For example, the external heating roller 108 is an aluminum cylindrical roller, and includes a cylindrical shaft section 108A at each end portion in a longitudinal direction thereof. A halogen heater 118 is provided at an inner side of the external heating roller 108. The halogen heater 118 serves as a heat source that is out of contact with an inner peripheral surface of the external heating roller 108. The halogen heater 118 generates heat by application of current of a power supply (not shown), and, for example, heats the external heating roller 108 to a temperature that is higher than the temperature of the fixing roller 102 by approximately 50° C. to 70° C.
The external heating roller 108 is provided so as oppose the outer peripheral surface of the fixing roller 102. The external heating roller 108 is moved by an operation of the retracting mechanical section 140 (described later; see
As shown in
The eccentric cam 142 has a rotary shaft 142A whose axial direction is the same as the axial direction of the external heating roller 108. The eccentric cam 142 is rotationally driven in the direction of arrow +R or in the direction of arrow −R by a motor (not shown) that is driven by the controller 20 (see
The bracket 144 has a recessed portion 144A at a center thereof as viewed in the axial direction of the external heating roller 108. A flat portion 144B is formed outwardly from a peripheral edge of the recessed portion 144A (that is, outwardly in a direction crossing the direction of arrow X). The upper bracket 144 is disposed in the −X direction from the eccentric cam 142. An open side of the recessed portion 144A is disposed so as to oppose the eccentric cam 142. An upper follower 143 is provided at the upper bracket 144. The upper follower 143 is rotatably provided at the recessed portion 144A and rotates by contacting an outer peripheral surface of the eccentric cam 142.
The lower bracket 146 has a recessed portion 146A at a center thereof as viewed in the axial direction of the external heating roller 108. A flat portion 146B is formed outwardly from a peripheral edge of the recessed portion 146A (that is, outwardly in a direction crossing the direction of arrow X). The lower bracket 146 is disposed in the +X direction from the eccentric cam 142. An open side of the recessed portion 146A is disposed so as to oppose the eccentric cam 142. A lower follower 145 is provided at the lower bracket 146. The lower follower 145 is rotatably provided at the recessed portion 146A and rotates by contacting the outer peripheral surface of the eccentric cam 142.
Here, the upper bracket 144 and the lower bracket 146 are fastened to each other with bolts and nuts (not shown) with the flat portion 144B and the flat portion 146B being in contact with each other so that the recessed portion 144A and the recessed portion 146A are disposed on both sides of the eccentric cam 142. A center of rotation of the eccentric cam 142, a center of rotation of the upper follower 143, and a center of rotation of the lower follower 145 are disposed on a same line in the direction of arrow X. The directions of movements of the upper bracket 144 and the lower bracket 146 are restricted to only the +X direction and the −X direction by a guide member (not shown).
A bearing (not shown) is mounted to the supporting bracket 150. The bearing rotatably supports the external heating roller 108. Although a pair of supporting brackets 150 are provided, one at each end of the external heating roller 108, only one of the supporting brackets 150 will be shown here. The movement of the supporting bracket 150 is restricted to only the +X direction and the −X direction by a guide member (not shown).
Further, the flange 148 of the bracket 150 protrudes from the supporting bracket 150 in the axial direction of the external heating roller 108. The flange 148 is disposed so that its open side faces the lower bracket 146. With the directions of arrow X being defined as the directions of expansion and contraction of the springs 152, one end of each spring 152 is secured to the flat portion 146B of the lower bracket 146, and the other end of each spring 152 is secured to the flat portion 148A of the flange 148.
Here, in the retracting mechanical section 140, when the eccentric cam 142 and the lower follower 145 contact each other, and the upper bracket 144 and the lower bracket 146 move in the +X direction, the springs 152 bias the flange 148 in the +X direction. This causes the supporting bracket 150 to move in the +X direction, so that the external heating roller 108 contacts the outer peripheral surface of the fixing roller 102 (hereunder referred to as a contacting operation of the retracting mechanical section 140).
In contrast, when the eccentric cam 142 and the upper follower 143 contact each other, and the upper bracket 144 and the lower bracket 146 move in the −X direction, a force acts in a direction in which each spring 152 contracts, so that the flange 148 is pulled in the −X direction. This causes the supporting bracket 150 to move in the −X direction, so that the external heating roller 108 separates from the outer peripheral surface of the fixing roller 102 (hereunder referred to as a retracting operation of the retracting mechanical section 140). In this way, the retracting mechanical section 140 switches between a state in which the external heating roller 108 contacts the fixing roller 102 and a state in which the external heating roller 108 does not contact the fixing roller 102.
As shown in
As shown in
The pressure roller 104 is disposed below the fixing roller 102 at the transport path of the recording paper P. In an example of the pressure roller 104, an outer periphery of an aluminum cylindrical core bar 104B is covered by silicone rubber 104A, and a surface layer having separability allowing recording paper to separate therefrom (not shown) formed of fluorocarbon resin is formed along an outer peripheral surface of the silicone rubber 104A. A halogen heater 116 is provided inwardly from the core bar 104B. The halogen heater 116 serves as a heat source that is out of contact with an inner peripheral surface of the core bar 104B. The halogen heater 116 generates heat by application of current from a power supply (not shown), and heats the core bar 104B, so that the entire pressure roller 104 is heated.
At a side close to the opening 106A, a third temperature sensor 128 that detects the temperature of the pressure roller 104 is provided so as to oppose the outer peripheral surface of the pressure roller 104, and so as to be out of contact with the pressure roller 104. The third temperature sensor 128 has the same structure as the first temperature sensor 132. Here, the first temperature sensor 132, the second temperature sensor 126, and the third temperature sensor 128 are connected to the controller 20 (see
Further, bearings (not shown) are provided at corresponding end portions of the pressure roller 104. The bearings are mounted to a central portion of a V-shaped bracket 124. The bracket 124 is provided so as to be rotatable in the direction of arrow +R or the direction of arrow −R around a shaft section 122, mounted to the housing 106, by an operation of an eccentric cam (not shown). By this, when the bracket 124 moves in the direction of arrow +R, the pressure roller 104 contacts the fixing roller 102, to form a contact portion N (nip), whereas, when the bracket 124 moves in the direction of arrow −R, the pressure roller 104 separates from the fixing roller 102.
Next, the applying unit 110 will be described.
As shown in
In a structure in which the applying roller 112 is not required to retract from the fixing roller 102, the applying unit 110 does not require the retracting mechanical section 160. In a structure in which the applying roller 112 is driven and rotated with respect to the fixing roller 102, it is not necessary to provide the driving section 113. In an exemplary structure in the applying roller 112 is driven and rotated, the applying roller 112 is rotatably supported and is brought into contact with the fixing roller 112 to apply a load to an end portion of a rotary shaft of the applying roller 112. This causes a difference to occur between the peripheral velocity of the fixing roller 102 and the peripheral velocity of the applying roller 112.
As shown in
In an exemplary method of producing the applying roller 112, resin powder containing polytetrafluoroethylene is electrostatically coated (that is, is coated while applying voltage) on the outer peripheral surface of the core bar 112A to which an adhesive layer (primer layer) is applied. Then, the core bar 112A on which the resin powder is coated is heated to a temperature that is higher than the crystalline melting point of the resin powder. In an environment without oxygen, polytetrafluoroethylene that is not cross-linked is irradiated with ionizing radiation (such as γ rays, electron rays, X rays, neutron rays, or high-energy ions) whose quantity of radiation is in the range of from at least 1 KGy to 10 MGy at most. This causes cross-linking to be performed to obtain cross-linked polytetrafluoroethylene that covers the outer peripheral surface of the core bar 112A.
As shown in
As shown in
Each supporting lever 162 is formed of a steel plate, and includes a first lever section 162A, a second lever section 162B, and a third lever section 162C, which form an integrated structure. The first lever section 162A extends obliquely in an upper right direction in
A bearing 163 is mounted to an illustrated lower end of the first lever section 162A. A rotary shaft 165 secured to the housing 106 (see
A bracket (not shown) is provided at the center of the first lever section 162A so as to be slidable towards the fixing roller 102. A bearing 167 is mounted to the bracket. The bearing 167 rotatably supports both ends of the applying roller 112. Here, a spring (not shown) biases the bracket towards the fixing roller 102. Even if the diameter of the applying roller 112 becomes smaller than its diameter in an initial state as the applying material 112B is consumed, the applying roller 112 contacts the outer peripheral surface of the fixing roller 102. The driving section 113 is formed so that, even if the applying roller 112 is moved, driving force is transmitted from the driving section 113 to the applying roller 112.
A bearing 168 is mounted to the bent portion between the first lever section 162A and the second lever section 162B. The bearing 168 rotatably supports both end portions of the cleaning roller 120. A follower 169 forming a portion of each supporting lever 162 is rotatably mounted to the bent portion between the second lever section 162B and the third lever section 162C.
An upper end portion of the third lever section 162C is provided with a catching section 171 formed by cutting and bending a portion of the third lever section 1620. A securing section 173 for securing an end of a spring 172 is provided in the housing 106 (see
A pressing force that causes the applying roller 112 to press the fixing roller 102 when the spring 172 biases each supporting lever 162 is set, for example, at approximately ⅓ of a pressing force that causes the external heating roller 108 to press the fixing roller 102 when the springs 152 of the retracting mechanical section 140 shown in
As shown in
Here, by rotating the cam 164 in the direction of arrow +R, each supporting lever 162 reciprocates in the direction of arrow +D or in the direction of arrow −D around the rotary shaft 165. As shown in
In contrast, as shown in
As shown in
Next, the operation according to the first exemplary embodiment will be described.
In the fixing device 100 shown in
In contrast, when a fixing operation is not performed by the fixing device 100 (for example, when the fixing device 100 is in a standby state after the fixing operation has ended), a retracting operation of the retracting mechanical section 140 (see
Next, as shown in
By elastic force that causes the elastic member 120B, provided at the outer peripheral surface of the cleaning roller 120, to be restored to its original shape, the cleaning roller 120 scrapes off the extraneous matter E from the outer peripheral surface of the fixing roller 102. This causes the hard extraneous matter E to be removed even if the hard extraneous matter E adheres to the outer peripheral surface of the fixing roller 102. Since the cleaning roller 120 is rotated and driven with respect to the rotation of the fixing roller 102, application of excess load to the rotation of the fixing roller 102 is suppressed.
The elastic member 120B of the cleaning roller 120 is formed of silicone rubber. The outer peripheral surface of the cleaning roller 120 is not provided with a surface layer having separability allowing recording paper to separate therefrom formed of fluorocarbon resin. Attraction force between the extraneous matter E and the cleaning roller 120 that does not include a surface layer having separability allowing recording paper to separate therefrom is greater than attraction force between the extraneous matter E and the fixing roller 102 including the surface layer having separability allowing recording paper to separate therefrom 102C (see
Here, in the image forming apparatus 10 shown in
However, in the fixing device 100 according to the exemplary embodiment, as shown in
Therefore, as shown in
Further, in the fixing device 100, the toner T existing on a piece of A3-size recording paper P in the range of the width W2 is fused by being heated and pressed at the smooth surface 102E. Therefore, the surface during the hardening of the toner T is smoother than the rough surface 102D. Consequently, a reduction in image quality caused by the outer peripheral surface of the fixing roller 102 that is rough is suppressed.
In addition, in the fixing device 100, the applying material 112B contains cross-linked polytetrafluoroethylene of high molecular weight. Therefore, attraction force with respect to PFA of the surface layer having separability allowing recording paper to separate therefrom 102C of the fixing roller 102 is greater for the applying material 112B according to the exemplary embodiment containing cross-linked polytetrafluoroethylene than for a structure containing polytetrafluoroethylene that is not cross-linked. Consequently, when the applying material 112B is applied to the outer peripheral surface of the fixing roller 102 using the applying roller 112, the applying material 112B adheres to the outer peripheral surface of the fixing roller 102, so that it is not easily separated therefrom.
Here, a surface roughness Ra of a fixing roller 102 (to which the applying material 112B is not applied) according to a comparative example is measured at a portion where streaks are formed. The fixing roller 102 causes streaks to be formed in fixed toner images in accordance with the end-portion position PB. This measurement is performed using an ultradeep shape measurement microscope (product of Keyence Corporation: VK8510). The surface roughness Ra is from 0.17 μm to 0.33 μm, with an average value being approximately 0.23 μm.
A surface roughness Ra of the fixing roller 102 to which the applying material 112B is applied according to the exemplary embodiment is measured at the end-portion position PB using the same ultradeep shape measurement microscope (product of Keyence Corporation: VK8510). The surface roughness Ra is from 0.10 μm to 0.19 μm, with an average value being approximately 0.16 μm. This shows that the roughness of the outer peripheral surface of the fixing roller 102 (to which the applying material 112B is applied) according the exemplary embodiment is less than the roughness of an outer peripheral surface of the fixing roller 102 according to the comparative example.
Next, an exemplary applying device, an exemplary fixing device, and an exemplary image forming apparatus according to a second exemplary embodiment of the present invention will be described. Components according to the second exemplary embodiment that are basically the same as those according to the first exemplary embodiment will be given the same reference numerals as those in the first exemplary embodiment, and will not be described below.
The applying unit 190 includes an applying material 192, a holding member 195, an applying roller 194, a driving section 113, and a retracting mechanical section 160 (see
The applying roller 194 is a columnar roller formed of stainless steel (SUS). Its axial length is the same as that of the applying roller 112 (see
In a structure in which the applying roller 194 need not be retracted from the fixing roller 102, the applying unit 190 need not be provided with the retracting mechanical section 160. In a structure in which the applying roller 194 is to be driven and rotated with respect to the fixing roller 102, the driving section 113 need not be provided.
The holding member 195 includes holding portions (not shown) at corresponding end portions thereof in a longitudinal direction of the holding member 195 for holding corresponding end portions of the applying material 192. The holding member 195 is replaceably mounted to each supporting lever 162 (see
Here, in the applying unit 190, when the holding member 195 is mounted to each supporting lever 162 in the housing 106 (see
Next, an operation according to the second exemplary embodiment will be described.
In the fixing device 180 shown in
In contrast, when a fixing-operation is not performed by the fixing device 180 (for example, when the fixing device 180 is in a standby state after the fixing operation has ended), a retracting operation of the retracting mechanical section 140 (see
Subsequently, as shown in
Next, as shown in
Since, at the application position PA, a peripheral velocity difference (V2−V1) occurs between the peripheral velocity of the applying roller 194 and the peripheral velocity of the fixing roller 102, the applying material 192 at the outer periphery of the applying roller 194 is transferred to the outer peripheral surface of the fixing roller 102 by friction force. In addition, the applying material 192 is held by the outer peripheral surface of the fixing roller 102 after passing the application position PA. Therefore, as shown in
Further, in the fixing device 180, toner T existing on a piece of recording paper P is fused by being heated and pressed at the smooth surface 102E. Therefore, the surface during the hardening of the toner T becomes smooth. Consequently, a reduction in image quality caused by the roughness of the outer peripheral surface of the fixing roller 102 is suppressed.
In addition, in the fixing device 180, the applying material 192 contains cross-linked polytetrafluoroethylene of high molecular weight. Therefore, attraction force with respect to PFA of the surface layer having separability allowing recording paper to separate therefrom 102C (see
In addition, in the fixing device 180, the applying material 192 is independently provided of the applying roller 194. When the applying material 192 is replaced, the applying roller 194 need not be replaced. Therefore, compared to a structure in which the applying material 192 directly contacts the fixing roller 102, the applying material 192 is easily replaced. Further, since it is not necessary to perform cross-linking after resin powder prior to cross-linking is electrostatically applied to the roller, the applying unit 190 is easily manufactured.
The present invention is not limited to the above-described exemplary embodiments.
As shown in
As shown in
In a second modification, as shown in
In a third modification, as shown in
In addition, instead of using the fixing roller 102, fixing belt that is heated by electromagnetic induction may be used. The types of recording paper P are not limited to A4-size recording paper or A3-size recording paper. They may include recording paper P of other sizes. The applying material 192 is not limited to a plate material. It may be a sheet material, a block material, or a chip material. The application of the applying material is not limited to application by a roller member. The applying material may be applied to the outer peripheral surface of the fixing roller 102 using an endless belt member. Alternatively, the applying material may be applied by directly pressing a plate member against the fixing roller 102.
Other examples of fluorocarbon resin materials that may be used are tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene tetrafluoroethylene copolymer (ETFE), polyvinylidene difluoride (PVDF), and polychloro-trifluoroethylene.
Further, the applying roller 112 and the applying roller 194 are not limited to those that are independently driven by the driving section 113 as mentioned above. They may be driven and rotated with respect to the fixing roller 102 to form a layer of the applying material 112B (or the applying material 192). When the cleaning is performed using the external heating roller 108, the cleaning roller 120 need not be used. In addition, it is possible to cause the applying material 192 to contact the outer peripheral surface of the pressure roller 104, and use the pressure roller 104 as the applying member of the applying material 192.
The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
Number | Date | Country | Kind |
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2011-151091 | Jul 2011 | JP | national |