JP2005266079A - Image forming apparatus, wax removal device and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which permits the enhancement of the gloss (brilliance) by making continuous removal of wax possible even when the wax is included in a toner image after fixing, to provide a wax removal device and to provide an image forming method. <P>SOLUTION: The toner image formed with toner material is thermally fixed on the surface 71 of a recording medium 70 by a fixing device 29. A wax removal part 60 allows a blade 61 to contact with the surface 71 of the recording medium 70 at a temperature not lower than the melting point of the wax included in the toner image which is thermally fixed by the fixing device 29 and lower than the melting point of the toner material and, thereby, removes the wax on the surface 71 of the recording medium 70. A distance between the fixing device 29 and the blade 61 is determined so that the recording medium 70 causes temperature drop in accordance with the conveyance and the temperature of the surface 71 falls into the temperature range. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus using, for example, an electrophotographic system, and more particularly to an image processing apparatus that heats and melts a toner image formed on a recording medium and fixes the toner image on the recording medium.

  In an image forming apparatus such as a printer or a copier using an electrophotographic method, an electrostatic latent image is formed on the surface of an image carrier made of a drum or belt-shaped organic photoconductor by a known electrophotographic process, The electrostatic latent image is developed with toner to form a toner image, and then the toner image is electrostatically transferred to a recording medium (such as paper) directly or via an intermediate transfer member, and then, for example, by a heat fixing mechanism. Image formation is performed by fixing a toner image on a recording medium. As the heat fixing mechanism, a radiant method, a flash method, a two-roller method using a heating roller and a pressure roller, a free belt nip method using a heating roller and a backup free belt, and the like are used. Taking a two-roller system as an example, a fixing unit is provided with a roller pair composed of, for example, a heating roller heated by a heater and a pressure roller covered with an elastic body. The unfixed toner image is fixed on the recording medium by passing between the pair of rollers. In an image forming apparatus capable of forming a full-color image, for example, toner images of four colors Y (yellow) M (magenta) C (cyan) K (black) are transferred to a recording medium, and the recording having the toner images of these four colors is performed. The medium is fixed by passing through the roller pair to form a full-color image.

  The toner used for fixing such a full-color image is required to have high meltability and color mixing properties when heat is applied, and preferably has a high so-called sharp melt property. On the other hand, the releasability from the toner such as the heating roller is not sufficient, and particularly toner having a high sharp melt property tends to be offset to the heating roller or the like at the time of fixing. Therefore, conventionally, silicon oil or the like is applied to the heating roller or the like to improve the toner releasability and prevent the offset to the heating roller or the like. However, in order to apply oil such as silicon oil to the heating roller, it is necessary to separately provide a device for supplying oil, which causes a problem that the device becomes complicated. Another problem is that the stickiness of oil on the output recording medium cannot be avoided. Therefore, an apparatus for forming an image using an oilless toner that does not require external oil supply instead of applying silicon oil has been developed. In this oilless toner, a release agent such as polyethylene wax, paraffin wax, silicon wax, or the like is added to the toner, so that the toner containing the colorant is given release properties.

  Here, when the oilless toner as described above is used, the glossiness is generally impaired due to the presence of the wax. However, in recent years, even when such a wax is used, the color reproducibility is wide and the glossiness is as high as printing. Is issued as a request for image quality. Therefore, in order to realize a high gloss (high gloss) image quality, a technique for encapsulating a wax made of a material having a high melting property in a toner has been studied.

  As described above, the toner containing wax is mainly used to prevent the image remaining on the heat fixing device. However, in the toner containing wax, a wax component is deposited on the surface of the image quality of the recording medium. Occurs, leading to a decrease in gloss and color of the image.

  As a conventional technique described in the publication, for example, there is a technique for cleaning an unnecessary material including a wax component on the surface of a recording medium after fixing (see, for example, Patent Document 1).

JP 2002-91205 A (page 4-5, FIG. 1)

However, since the wax removal method according to the above prior art depends on the adsorptivity of the cloth or the porous body, the removal performance may be greatly influenced by the material characteristics. For example, it is necessary to use an adsorbent material such as “Wosep” (manufactured by Toray Industries, Inc.), “Power Soap” (manufactured by Sumitomo 3M Ltd.), and substitution with other general materials may be difficult.
In addition, when used repeatedly for wax removal, the adsorptivity decreases in function, so that the wax removal performance gradually decreases from the start of use, and there remains a problem that image quality varies for each sheet.
Furthermore, since the removal of the wax removal material becomes saturated, it cannot be removed at all. Therefore, it is necessary to replace the wax removal material for long-term use or continuous use, and there is a concern that the running cost may be expensive. Yes.

  The present invention has been made to solve the technical problems as described above, and an object of the present invention is to provide a continuous wax even when the toner image after fixing contains a wax. It is intended to improve the gloss (glossiness) by enabling removal.

For this purpose, the image processing apparatus to which the present invention is applied employs a direct removal method by contact, focusing on the melting point difference between the wax component and the toner material component in the toner image. That is, a fixing unit that heat-fixes a toner image formed with a toner material on a recording medium, and a temperature that is equal to or higher than the melting point of the wax contained in the toner image heat-fixed by the fixing unit and lower than the melting point of the toner material. And a wax removing means for removing the wax on the surface of the recording medium by bringing the wax non-adsorbing member into contact with the surface of the recording medium. The non-wax-absorbing member here means a material other than a cloth or the like that can adsorb wax, and is made of a rubber material or a film material that does not melt at the melting point of the toner material. Examples include a blade that scrapes off wax by bringing a relatively hard end into contact with the surface. The wax used here may be a release agent wax having a melting point lower than that of the toner material.
Here, the portion of the wax removing unit that contacts the surface of the recording medium of the wax non-adsorbing member has at least the same length as the length of the recording medium in the direction orthogonal to the conveyance direction of the recording medium. it can.
Further, the wax removing means may include an opposing roll disposed on the back side of the recording medium, and the wax removal may be performed by sandwiching the recording medium between the opposing roll and the non-wax-adsorbing member.

Here, the position of the wax removing unit from the fixing unit can be characterized in that it is determined based on a temperature drop accompanying the conveyance of the surface of the recording medium on which the toner image is heated and fixed. In addition, the wax removing means includes a temperature setting unit that sets the temperature of the surface of the recording medium in contact with the wax non-adsorbing member to a temperature that is equal to or higher than the melting point of the wax included in the toner image and lower than the melting point of the toner material. Can be a feature.
The wax removing unit may include a moving unit that moves the wax non-adsorbing member so as to be movable toward and away from the recording medium. Further, the wax removing means may be provided with a wax accommodating portion for accommodating the wax removed from the surface of the recording medium.

  Further, from another point of view of the present invention, the wax removing apparatus to which the present invention is applied is installed in an image forming apparatus, and is a recording in which a toner image formed with a toner material is heated and fixed. A receiving means for receiving the medium, and a wax that removes the wax on the entire surface of the recording medium by bringing the wax non-adsorbing member into contact with the surface of the recording medium at a temperature equal to or higher than the melting point of the wax contained in the toner image and lower than the melting point of the toner material Removing means.

  On the other hand, an image forming method to which the present invention is applied includes a recording medium on which a toner image image-formed with a toner material in an image forming apparatus is heated and fixed. The wax deposited on the surface of the recording medium is scraped by bringing the end of the wax non-adsorbing member into contact with the surface of the recording medium. Here, it may be further included that the wax non-adsorbing member is in contact with the surface of the recording medium in the high gloss mode and is not in contact in the low gloss mode.

  According to the present invention, it is possible to improve the gloss (glossiness) by continuously removing the wax even if the toner image after fixing contains wax.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a diagram showing the overall configuration of an image forming apparatus according to the present embodiment, and shows a so-called tandem type digital color printer. An image forming apparatus shown in FIG. 1 includes an image processing system 10 that forms an image corresponding to gradation data of each color, a sheet conveyance system 40 that conveys a recording medium (a sheet member such as paper), for example, a personal computer. An IPS (Image Processing System) 50, which is an image processing system connected to a computer, an image reading device, or the like, and performs predetermined image processing on received image data. A wax removing unit 60 is provided for removing the wax contained in the toner image.

  The image processing system 10 includes four image forming units 11Y, 11M, yellow (Y), magenta (M), cyan (C), and black (K) arranged in parallel at a certain interval in the horizontal direction. 11C, 11K. Further, the transfer unit 20 that multiplex-transfers the toner images of the respective colors formed on the photosensitive drums 12 of the image forming units 11Y, 11M, 11C, and 11K onto the intermediate transfer belt 21, and the image forming units 11Y, 11M, 11C, and 11K. Is provided with a ROS (Raster Output Scanner) 30 which is an optical system unit for irradiating a laser beam. Further, the image (toner image) on the recording medium secondarily transferred by the transfer unit 20 is fixed to the main body 1 on the recording medium using heat and pressure roller 29a and pressure roller 29b, for example. A fixing device 29 is provided. Further, toner cartridges 19Y, 19M, 19C, and 19K are provided for supplying toner of each color to the image forming units 11Y, 11M, 11C, and 11K.

  Each color toner supplied to the toner cartridges 19Y, 19M, 19C, and 19K is melted, kneaded, pulverized, classified, and polymerized with polyester resin, colorant (dye, sublimation dye), charge control material, and the like. It is manufactured by. In order to transfer the toner image formed on the image bearing member onto the intermediate transfer member or the recording medium, an external additive having releasability can be added. In consideration of offset resistance, fixing properties, and sharp melt properties, color toners using a polyester resin as a binder resin are particularly preferable. Further, the toner used in the present embodiment contains, for example, 0.1 wt% to 40 wt% wax. By including the wax in the toner, the wax acts as a release agent, and a wider fixing latitude can be obtained even when the release oil is not used on the surface of the heat fixing roller 29 a provided in the fixing device 29. The fixing latitude means that the toner image is separated from the heat fixing roller 29a from the low temperature side (minimum fixing temperature) at which the unfixed toner image can be fixed on the recording medium when the temperature of the heat fixing roller 29a is changed. This refers to the temperature range up to the temperature on the high temperature side where the mold cannot be formed (offset generation temperature).

  By setting the wax content in the toner to about 0.1% by weight, the offset generation temperature rapidly increases, and when the wax content is further increased, the offset generation temperature gradually increases. On the other hand, the minimum fixing temperature gradually increases as the wax content increases. When the wax content exceeds 40% by weight, the minimum fixing temperature becomes extremely high. Therefore, by setting the wax content to 0.1 to 40% by weight, preferably about 1 to 10% by weight, a low fixing latitude and a low fixing temperature can be realized.

  The melting point of the wax is, for example, 110 ° C. or less, for example, the melting point is 80 ° C. to 100 ° C. By making the melting point of the wax somewhat lower than the melting point of the binder resin in the toner, the wax is effectively dissolved out of the toner before the binder resin. As a result, the wax is interposed at the interface between the toner and the heat-fixing roller 29a when the heat-fixing roller 29a and the pressure roller 29b are separated at the exit of the nip portion, thereby effectively improving the release performance. Can do.

  The wax used in the toner to which the exemplary embodiment is applied is not particularly limited as long as it has releasability, and specific examples include the following materials. Waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, and rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, and petrolatum. And petroleum wax. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, and chlorinated hydrocarbons, esters Synthetic waxes such as ketones and ethers can also be used. Further, as a low molecular weight crystalline polymer resin, a polyacrylate homopolymer or copolymer such as poly n-stearyl methacrylate and poly n-lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate) Examples thereof include crystalline polymers having a long acrylic group in the side chain. Among these, more preferable are petroleum waxes such as paraffin wax and microcrystalline wax, or synthetic waxes.

  Further, the binder resin in the toner suitable for the present embodiment is not particularly limited, and a resin (polymer) generally used as a binder resin for toner can be used. More specifically, polyester resin, styrene resin, acrylic resin, styrene / acrylic resin, silicone resin, epoxy resin, diene resin, phenol resin, ethylene / vinyl acetate resin, etc. are particularly preferable. A polyester resin is mentioned as follows. When a polyester resin is used as a binder resin, an image having high surface smoothness and excellent transparency can be formed even when the molecular weight is large.

  On the other hand, the transfer unit 20 includes a drive roller 22 that drives an intermediate transfer belt 21 that is an intermediate transfer member, a tension roller 23 that applies a certain tension to the intermediate transfer belt 21, and a toner image of each superimposed color on a recording medium. A backup roller 24 for the next transfer and a cleaning device 25 for removing residual toner and the like existing on the intermediate transfer belt 21 are provided. The intermediate transfer belt 21 is wound around the drive roller 22, the tension roller 23, and the backup roller 24 with a constant tension, and is driven to rotate by a dedicated drive motor (not shown) excellent in constant speed. The drive roller 22 is driven to circulate at a predetermined speed in the direction of the arrow. As the intermediate transfer belt 21, for example, a belt whose resistance is adjusted with a belt material (rubber or resin) that does not cause charge-up is used. The cleaning device 25 includes a cleaning brush 25a and a cleaning blade 25b, and removes residual toner, paper dust, and the like from the surface of the intermediate transfer belt 21 after the toner image transfer process is completed, and performs the next image forming process. It is comprised so that it may prepare for.

  In addition to a semiconductor laser and a modulator (not shown), the ROS 30 includes a polygon mirror 31 that deflects and scans laser light (LB-Y, LB-M, LB-C, and LB-K) emitted from the semiconductor laser. In the example shown in FIG. 1, since the ROS 30 is provided below the image forming units 11Y, 11M, 11C, and 11K, there is a risk of contamination due to dropping of toner or the like. Therefore, the ROS 30 is provided with a rectangular parallelepiped frame 32 for sealing each constituent member, and a glass window 33 through which laser light (LB-Y, LB-M, LB-C, LB-K) passes. Is provided above the frame 32 to enhance the shielding effect together with the scanning exposure.

  The sheet conveying system 40 includes a sheet feeding device 41 that stacks and supplies a recording medium (sheet) on which an image is recorded, a nudger roller 42 that picks up and supplies the recording medium from the sheet feeding device 41, and a recording medium that is supplied from the nudger roller 42. Are provided with a feed roller 43 that separates and conveys the recording medium one by one, and a conveyance path 44 that conveys the recording medium separated one by one by the feed roller 43 toward the image transfer unit. Further, a registration roller 45 that conveys the recording medium conveyed through the conveyance path 44 in time toward the secondary transfer position, and a backup roller 24 that is provided at the secondary transfer position and is in pressure contact with the recording medium. And a secondary transfer roller 46 for secondary transfer of the image. Further, a discharge tray 48 on which a recording medium on which the toner image is fixed by the fixing device 29 and discharged via the wax removing unit 60 is stacked is provided.

  Next, the operation of the image forming apparatus shown in FIG. 1 will be described. A color material reflected light image of a document read by a document reading device (not shown) and color material image data formed by a personal computer (not shown) are, for example, R (red), G (green), and B (blue). Each 8-bit reflectance data is input to the IPS 50. In IPS 50, the input reflectance data is subjected to predetermined image processing such as various image editing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, and moving editing. Is done. The image data that has been subjected to image processing is converted into color material gradation data of four colors of yellow (Y), magenta (M), cyan (C), and black (K), and is output to the ROS 30.

  In the ROS 30, laser light (LB-Y, LB-M, LB-C, LB-K) emitted from a semiconductor laser (not shown) is converted into f-θ in accordance with input color material gradation data. The light is emitted to the polygon mirror 31 through a lens (not shown). In the polygon mirror 31, the incident laser light is modulated in accordance with gradation data of each color, deflected and scanned, and image forming units 11Y, 11M, 11C, and 11K through an imaging lens and a plurality of mirrors (not shown). The photosensitive drum 12 is irradiated. On the photosensitive drums 12 of the image forming units 11Y, 11M, 11C, and 11K, the charged surface is subjected to scanning exposure to form an electrostatic latent image. The formed electrostatic latent image is developed as a toner image of each color of yellow (Y), magenta (M), cyan (C), and black (K) in each of the image forming units 11Y, 11M, 11C, and 11K. Is done.

  The toner images formed on the photosensitive drums 12 of the image forming units 11Y, 11M, 11C, and 11K are multiplex-transferred onto an intermediate transfer belt 21 that is an intermediate transfer member. At this time, the black image forming unit 11 </ b> K that forms a black toner image is provided on the most downstream side in the moving direction of the intermediate transfer belt 21, and the black toner image is finally transferred to the intermediate transfer belt 21. Is done.

  On the other hand, in the sheet conveying system 40, the nudger roller 42 rotates in synchronization with the image formation timing, and a recording medium of a predetermined size is supplied from the paper feeding device 41. The recording medium separated one by one by the feed roller 43 is conveyed to the registration roller 45 through the conveyance path 44 and is temporarily stopped. Thereafter, the registration roller 45 rotates in accordance with the movement timing of the intermediate transfer belt 21 on which the toner image is formed, and the recording medium is conveyed to the secondary transfer position formed by the backup roller 24 and the secondary transfer roller 46. . On the recording medium conveyed from the lower side to the upper side at the secondary transfer position, the toner images in which the four colors are multiplexed are sequentially transferred in the sub-scanning direction using a pressing force and a predetermined electric field. The recording medium on which the toner image of each color is transferred undergoes a fixing process with heat and pressure by the fixing device 29 and is then conveyed to the wax removing unit 60. The wax removing unit 60 is disposed at a position downstream of the fixing device 29 and before the recording medium is discharged outside the apparatus. In the wax removing unit 60, a wax removing process is performed according to a configuration described later, and the wax is discharged to a discharge tray 48 provided on the upper portion of the main body 1.

  Next, the wax removal process that is a characteristic configuration of the present embodiment will be described. The present embodiment pays attention to the melting point difference between the wax component and the toner material component in the toner image, adopts a direct removal method by contact, and thereby enables continuous removal of the wax.

  FIG. 2 is a configuration diagram showing the configuration of the wax removing unit 60. The wax removing unit 60 is in contact with the surface 71 of the recording medium 70 that has been subjected to the fixing process by heat and pressure by the fixing unit 29 and removes wax contained in the heat-fixed toner image (wax non-adsorbing). Member) 61, a facing roll 62 disposed so as to be in contact with the blade 61 so as to contact the back surface 72 of the recording medium 70, and a waste wax for accommodating the wax removed from the surface 71 of the recording medium 70 by the blade 61. And an accommodating portion 63.

  FIG. 3 is a perspective view showing the positional relationship among the facing roll 62, the blade 61, and the recording medium 70. As shown in the figure, the blade 61 has the same length as the horizontal dimension in the conveyance direction of the recording medium 70.

FIG. 4 is a graph showing the relationship between the weight average molecular weight and the melting point, where the vertical axis is the melting point (° C.) and the horizontal axis is the weight average molecular weight. A general toner material has a molecular weight of 10 ⁴ to 10 ⁵ , and a polyester or styrene butadiene mixed polymer is generally used as the toner material. The melting point of these materials is approximately 130 ° C. The fixing latitude with a molecular weight of 10 ⁴ is about 130 to 160 ° C., and the fixing latitude with a molecular weight of 10 ⁵ is about 140 to 200 ° C.

  In addition, the melting point of n-paraffin, which is common as a wax, is approximately 30 to 100 ° C. as is apparent from the table below, and is generally less than 100 ° C.

  Therefore, by setting the temperature during the wax removal process between the melting point of the wax and the melting point of the toner material, that is, about 100 to 130 ° C., only the wax is removed from the image using the toner material and the wax. be able to.

  FIG. 5 is a graph showing the relationship between the main material and the melting point of the blade 61, with the vertical axis indicating the melting point (° C.) and the horizontal axis indicating the main material. As is clear from the figure, thermosetting elastomers (ethylene-propylene polymer, etc.) have no melting point, and general film seal polyurethane has a melting point of about 160-60 ° C. Polyethilene Terephthalate) is approximately 220-260 ° C. As described above, the material of the blade 61 can be used as long as it does not melt at about 100 to 130 ° C., and a general rubber material (for example, urethane rubber such as a thermosetting elastomer) or a film material (for example, polyurethane). , PET) or the like. If the polyurethane has a melting point of 100 ° C. or lower, as shown in Table 1, for example, Nonadekane has a melting point of 32 ° C. Therefore, if the type of wax to be used is appropriately selected, the polyurethane is replaced with the blade 61. Material. That is, in this embodiment, a temperature that is equal to or higher than the melting point of the wax and lower than the melting point of the toner material is set as the temperature in the wax removal process, and the blade 61 is formed of a material having a higher melting point than the temperature in the wax removal process. With such a configuration, only the wax component contained in the toner image is directly removed by contact to enable continuous removal of the wax.

  FIG. 6 is a graph showing the relationship between the surface temperature of the recording medium 70 on which the toner image is heat-fixed by the fixing device 29 and the distance from the fixing device 29. The vertical axis is temperature (° C.) and the horizontal axis is fixing. The distance (mm) from the container 29. As is apparent from the figure, the temperature is about 160 ° C. immediately after being transported from the fixing device 29, but naturally cools down along with the transport and the temperature drops. At the position of 30 mm from the fixing device 29, the temperature is 153 ° C., the position at 60 mm is about 132 ° C., the position at 80 mm is about 95 ° C., and the position at 100 mm is about 70 ° C. Accordingly, if the position of the blade 61 is within the range of 60 to 80 mm downstream of the fixing device 29, the temperature will be appropriate for the wax removal process. As described above, in the present embodiment, the temperature setting in the wax removal processing is performed by changing the position of the blade 61 from the fixing device 29 based on the temperature drop of the surface 71 accompanying the conveyance of the recording medium 70 on which the toner image is heated and fixed. It is done by setting.

  Here, by setting the toner material to have a higher melting point and the wax having a lower melting point, it is possible to widen the appropriate temperature range for the wax removal treatment.

Since the present embodiment is configured as described above, it operates as follows. Since the recording medium 70 on which the toner image is heat-fixed by the fixing device 29 is sandwiched between the blade 61 and the opposing roll 62, the surface temperature is higher than the melting point of the wax component and lower than the melting point of the toner material. The upper end of the tape contacts the surface of the recording medium 70 and scrapes off (scraps off) the wax. That is, since the wax included in the toner image is directly removed by the upper end of the blade 61 coming into contact with the surface 71 of the recording medium 70, it is not necessary to use a high-cost adsorbing material as in the conventional adsorbing type. Adsorption performance does not deteriorate with use, and periodic replacement of the adsorbent material becomes unnecessary. For this reason, the wax removal performance does not deteriorate even if the replacement work is not performed regularly, and continuous wax removal can be performed. Note that the scraped wax is collected in the waste wax container 63 through the blade 61.
In addition, the length of the portion where the blade 61 contacts the surface 71 of the recording medium 70 has the same length as the horizontal dimension in the conveyance direction of the recording medium 70, so the recording medium 70 can be obtained with one blade 61. The wax can be removed over the entire surface, and the configuration of the apparatus can be simplified.
In addition, since the recording medium 70 is sandwiched between the opposing roll 62 and the blade 61 to remove the wax, a stable contact state between the blade 61 and the recording medium 70 can be secured, and more reliable wax removal can be performed. it can.
Further, the position of the blade 61 from the fixing device 29 is set to an appropriate temperature in the wax removal process due to the temperature drop of the surface 71 accompanying the conveyance of the recording medium 70 on which the toner image is heated and fixed. Therefore, the increase in the number of components due to the wax removal process can be suppressed as much as possible, and the enlargement of the image forming apparatus can be prevented.

Here, a configuration in the case where the position of the blade 61 from the fixing device 29 cannot be a place where the wax removal process is at an appropriate temperature will be described with reference to FIG. FIG. 7 is a configuration diagram illustrating the configuration of the wax removing unit 60 according to a modification. As shown in the figure, a temperature setting unit 64 is provided between the fixing device 29 and the blade 61. The temperature setting unit 64 is a heating unit or a cooling unit. That is, when the surface temperature of the recording medium 70 at the position of the blade 61 is lower than the appropriate temperature for the wax removal process, a heating unit (a heat source or the like) is provided as the temperature setting unit 64, while when it is higher than the appropriate temperature, the temperature setting unit 64. By providing a cooling part (fan or the like), it is possible to achieve an appropriate temperature for the wax removal process. By adding the temperature setting unit 64 in this manner, the positional relationship between the fixing device 29 and the blade 61 becomes arbitrary, and the degree of freedom in the apparatus layout can be increased.
The temperature setting unit 64 is provided with a temperature sensor (not shown) for detecting the surface temperature of the recording medium 70, and based on the detection result of the temperature sensor, the surface 71 of the recording medium 70 is set to an appropriate temperature for the wax removal process. It can also be configured such that it can be heated or cooled. With this configuration, it is possible to cope with a case where the temperature gradient due to natural air cooling varies depending on the temperature outside the apparatus.

  Furthermore, the present embodiment can be expanded to include a moving mechanism (moving unit) that moves the blade 61 so as to be able to contact and separate from the recording medium 70. An example thereof will be described with reference to FIG. FIG. 8 is a configuration diagram illustrating a configuration of the wax removing unit 60 according to a modification. As shown in the figure, the blade 61 is rotatably held at its intermediate portion by a fulcrum 65, and the lower end portion is biased by a tension spring 66 so that the upper end portion is pressed in the direction of the opposing roll 62. Yes. A solenoid switch 67 is attached to the upper end side. A controller 68 is electrically connected to the solenoid switch 67, and the solenoid switch 67 is on / off controlled by a signal from the controller 68. As described above, it is possible to switch whether the blade 61 is in contact with the surface 71 of the recording medium 70 or not in contact with the signal of the controller 68. Therefore, switching between contact and non-contact can be performed as necessary. For example, it is conceivable that the blade 61 is in contact with the surface 71 of the recording medium 70 in the high gloss mode and is not in contact in the low gloss mode. FIG. 8 shows an example of the moving mechanism, and the moving mechanism can be configured by using other well-known and conventional techniques.

  In this embodiment, the wax removing unit is installed in the main body 1 of the image forming apparatus. However, it may be configured as a wax removing apparatus. That is, the wax removing device can be installed in the main body 1 of the image forming apparatus. The wax removing device has a receiving portion that receives a recording medium 70 on which a toner image formed with a toner material is heat-fixed in the main body 1 of the image forming apparatus, and is conveyed from the receiving portion to the wax removing portion. The The wax removal process in the wax removal unit is performed with the same content as described above. The wax removal apparatus can be configured to discharge the recording medium subjected to the wax removal process to the discharge tray 48. In the case of double-sided printing, the recording medium that has been subjected to the wax removal process can be discharged again to the main body 1 of the image forming apparatus.

  As described above in detail, according to the present embodiment, it is possible to continuously remove the wax contained in the toner image to improve the gloss of image quality and prevent uneven gloss.

  Examples of utilization of the present invention include utilization in image forming apparatuses such as printers and copiers that perform image formation using toner containing wax, and image forming methods using toner containing wax.

1 is a diagram illustrating an overall configuration of an image forming apparatus according to an exemplary embodiment. It is the figure which showed the structure of the wax removal part. It is the perspective view which showed the structure of the wax removal part. It is the graph which showed the relationship between a weight average molecular weight and melting | fusing point, a vertical axis | shaft is melting | fusing point (degreeC) and a horizontal axis is a weight average molecular weight. It is the graph which showed the relationship between the main material of a braid | blade, and melting | fusing point, and a vertical axis | shaft is melting | fusing point (degreeC). 4 is a graph showing the relationship between the distance from the fixing device and the surface temperature of the recording medium, with the vertical axis representing temperature and the horizontal axis representing distance. It is the block diagram which showed the structure of the wax removal part by the modification of this Embodiment. It is the block diagram which showed the structure of the wax removal part by the modification of this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 29 ... Fixing device, 60 ... Wax removal part, 61 ... Blade, 62 ... Opposite roll, 63 ... Waste wax accommodating part, 64 ... Temperature setting part, 65 ... Supporting point, 66 ... Extension spring, 67 ... Solenoid switch, 68 ... Controller, 70 ... recording medium, 71 ... front surface, 72 ... back surface

Claims (12)

Fixing means for heating and fixing a toner image formed with a toner material on a recording medium;
A wax non-adsorbing member is brought into contact with the surface of the recording medium at a temperature equal to or higher than the melting point of the wax contained in the toner image heat-fixed by the fixing unit and lower than the melting point of the toner material to remove the wax on the surface of the recording medium. An image forming apparatus comprising: a wax removing unit.   The portion of the wax removing unit that contacts the surface of the recording medium of the wax non-adsorbing member has at least the same length as the length of the recording medium in a direction orthogonal to the conveyance direction of the recording medium. Item 2. The image forming apparatus according to Item 1. The wax removing means comprises an opposing roll disposed on the back side of the recording medium;
The image forming apparatus according to claim 1, wherein a wax is removed by sandwiching a recording medium between the facing roll and the non-wax-adsorbing member.   The image forming apparatus according to claim 1, wherein the position of the wax removing unit from the fixing unit is determined based on a temperature drop accompanying conveyance of the surface of the recording medium on which the toner image is heat-fixed. apparatus.   The wax removing unit includes a temperature setting unit that sets the temperature of the surface of the recording medium in contact with the wax non-adsorbing member to a temperature that is equal to or higher than the melting point of the wax included in the toner image and lower than the melting point of the toner material. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 1, wherein the wax removing unit includes a moving unit configured to move the wax non-adsorbing member so as to come into contact with and separate from the recording medium.   The image forming apparatus according to claim 1, wherein the wax removing unit includes a wax accommodating portion for accommodating the wax removed from the surface of the recording medium. A wax removing device installed in an image forming apparatus,
Receiving means for receiving a recording medium on which a toner image formed with a toner material is heat-fixed;
Wax removing means for removing the wax on the entire surface of the recording medium by bringing a wax non-adsorbing member into contact with the surface of the recording medium at a temperature equal to or higher than the melting point of the wax contained in the toner image and lower than the melting point of the toner material. Including wax removal equipment.   9. The wax removing apparatus according to claim 8, wherein the wax removing unit includes a moving unit that moves the wax non-adsorbing member so as to come into contact with and separate from the recording medium.   9. The wax removing apparatus according to claim 8, wherein the wax removing means includes a wax containing portion for containing the wax removed from the surface of the recording medium. The recording medium on which the toner image formed with the toner material in the image forming apparatus is heated and fixed is set to a temperature that is equal to or higher than the melting point of the wax included in the toner image and lower than the melting point of the toner material.
An image forming method, wherein the wax deposited on the surface of the recording medium is scraped off by bringing an end of a wax non-adsorbing member into contact with the surface of the recording medium.   The image forming method according to claim 11, further comprising: contacting the surface of the recording medium with the wax non-adsorbing member in a high gloss mode, and non-contact in a low gloss mode.

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