Source: https://patents.google.com/patent/JP2006154560A/en
Timestamp: 2020-01-29 09:19:21
Document Index: 155519683

Matched Legal Cases: ['art 101', 'art 102', 'art 101', 'art 101', 'art 101', 'art 102', 'art 101', 'art 105', 'art 102', 'art 102', 'art 102', 'art 102', 'art 105']

JP2006154560A - Fixing device and image forming apparatus - Google Patents
JP2006154560A
JP2006154560A JP2004347677A JP2004347677A JP2006154560A JP 2006154560 A JP2006154560 A JP 2006154560A JP 2004347677 A JP2004347677 A JP 2004347677A JP 2004347677 A JP2004347677 A JP 2004347677A JP 2006154560 A JP2006154560 A JP 2006154560A
JP2004347677A
JP4264410B2 (en
2004-11-30 Application filed by Ricoh Co Ltd, 株式会社リコー filed Critical Ricoh Co Ltd
2004-11-30 Priority to JP2004347677A priority Critical patent/JP4264410B2/en
2006-06-15 Publication of JP2006154560A publication Critical patent/JP2006154560A/en
2009-05-20 Publication of JP4264410B2 publication Critical patent/JP4264410B2/en
<P>PROBLEM TO BE SOLVED: To provide a fixing device speedily increasing the temperature of the leading edge of a separating plate on the surface moving body side to the temperatures at which condensation does not occur, and to provide an image forming apparatus. <P>SOLUTION: The separating plate is designed so that its leading edge increases in temperature in preference to its other parts. Accordingly, the leading edge of the separating plate increases in temperature in preference to its other parts by a transfer material heated to a high temperature. Thus, the transfer material heated to such a high temperature speedily increases the temperature of the leading edge to the temperatures at which condensation does not occur. This prevents paper jamming. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI
The present invention relates to a fixing device and an image forming apparatus including the fixing device.
Conventionally, in an image forming apparatus, a latent image on an image carrier is developed with toner supplied from a developing device, and a toner image as a visible image is formed on the image carrier. The toner image on the image carrier is transferred to a transfer material by a transfer device, and fixed on the transfer material by a fixing device. As the fixing device, for example, a heater as a heat source is incorporated therein, and the fixing roller as one surface moving body configured to be rotatable, and the surface of the fixing roller can be rotated by contacting with a predetermined pressure. And a pressure roller as the other surface moving body. The toner image on the transfer material is fixed to the transfer material by heat and pressure at the nip formed by the fixing roller and the pressure roller. The transfer material on which the toner image is fixed at the nip portion is discharged through a paper discharge path. On the other hand, a transfer material that cannot be separated from the fixing roller or pressure roller after passing through the nip due to paper stiffness or the curvature of the fixing roller or pressure roller is forced by a separation plate provided with a tip near the nip. Thus, it is separated from the fixing roller or the pressure roller and discharged.
In general, the transfer material contains not a little moisture, and the transfer material is heated at the nip portion, so that the moisture contained in the transfer material is discharged from the transfer material as water vapor. The water vapor released from the transfer material is condensed when it comes into contact with the separation plate having a low temperature. Since the tip of the separation plate is disposed in the vicinity of the nip portion, the probability of contacting the transfer material is higher than that of other portions of the separation plate. For this reason, when condensation occurs at the leading end, there is a problem that there is a high probability that the transfer material will adhere to the leading end and a paper jam will occur.
Various proposals have been made to solve the problems caused by such condensation.
Patent Document 1 proposes a fixing device in which a notch for releasing water vapor generated from a transfer material is provided at the front end of a separation plate or the like. Thus, if the notch for releasing water vapor | steam is provided, it can suppress that dew condensation adheres to the front-end | tip part of a separation plate. However, the fixing device described in Patent Document 1 has a problem in that dew condensation occurs at the tip when the water vapor that has not been discharged from the notch for allowing the water vapor to escape adheres to the tip.
Therefore, in Patent Document 2, the separation plate is made of a thin metal or a material having high thermal conductivity with a small specific heat, and the separation plate is heated by contact with a transfer material heated to a high temperature, thereby causing condensation on the separation plate. There has been proposed a fixing device that raises the temperature to a temperature that is not. Heating the separation plate can prevent condensation from adhering to the tip of the separation plate.
JP 2003-202767 A JP-A-6-43772
However, in the fixing device described in Patent Document 2, it takes time until the leading end of the separation plate rises to a temperature at which no condensation occurs, and the tip reaches the leading end before the tip rises to a temperature at which no condensation occurs. There was a problem of condensation. In particular, when the device is left standing for a long time and the inside of the device is cooled, the temperature of the separation plate is low. Without increasing to a temperature at which it does not occur, there is a high probability that condensation will adhere to the tip.
As a result of intensive studies, the inventors of the fixing device described in Patent Document 2 cause the temperature of the entire separation plate to rise uniformly due to the heat of the transfer material. It has been found that it takes time to rise to a temperature where it does not occur.
The present invention has been made in view of the above problems, and its object is to fix the temperature of the front end portion of the separation plate on the surface moving body side quickly to a temperature at which no condensation occurs, and An image forming apparatus is provided.
In order to achieve the above-mentioned object, the invention of claim 1 is characterized in that two surface moving bodies driven at least one of them to move in the same direction in the nip while abutting each other to form a nip are provided. A heat source for heating at least one of the surface moving bodies is provided, and a transfer material having an unfixed toner image formed on the surface is sandwiched between the nips to heat and fix the toner image to the transfer material. The fixing device includes a separation plate that separates the transfer material, which has not been separated from the surface moving body after passing through the nip, from the surface moving body. It is characterized in that it is constructed so that the temperature rises preferentially as compared with the above part.
According to a second aspect of the present invention, in the fixing device of the first aspect, the separation plate is configured such that the heat capacity of the front end portion on the surface moving body side is lower than the other portions of the separation plate. To do.
The invention according to claim 3 is the fixing device according to claim 1 or 2, wherein the separation plate restricts the conduction of heat at the front end portion on the surface moving body side to the other portion of the separation plate. It is characterized by having a regulating means.
According to a fourth aspect of the present invention, in the fixing device according to any one of the first to third aspects, the separation plate includes a reinforcing portion that reinforces the front end portion on the surface moving body, and faces the front end portion on the surface moving body. The reinforcing portion is provided so as to face a portion of the surface moving body having a temperature higher than the surface average temperature in the axial direction of the surface moving body.
According to a fifth aspect of the present invention, in the fixing device according to the fourth aspect, the temperature of the portion of the surface moving body facing the reinforcing portion is higher than the surface average temperature in the axial direction of the surface moving body. The heat generation amount of the heat source is different in the axial direction.
According to a sixth aspect of the present invention, in the fixing device according to any one of the first to fifth aspects, the reinforcing portion is provided at a position facing an end portion of the transferred transfer material. is there.
According to a seventh aspect of the present invention, in the fixing device according to any one of the first to sixth aspects, the separation plate includes a water vapor receiving portion that receives water vapor generated from the transfer material, and water condensed in the water vapor receiving portion is The water vapor receiving portion is arranged at a position where it does not drop on the front end portion on the surface moving body side.
The invention according to claim 8 is the fixing device according to claim 7, wherein the water vapor receiving portion is provided at a position retracted from the front end portion on the surface moving body side with respect to the transfer surface of the transfer material. It is a feature.
According to a ninth aspect of the invention, in the fixing device of the seventh aspect, the water vapor receiving portion is formed of a member having low thermal conductivity.
According to a tenth aspect of the present invention, there is provided an image forming apparatus comprising: a toner image forming unit that forms a toner image on a transfer material; and a fixing unit that fixes the toner image on the transfer material. The fixing device according to any one of 9 to 9 is used.
According to the first to tenth aspects of the present invention, the front end portion of the separation plate on the surface moving body side is configured to preferentially rise in temperature compared to other portions of the separation plate, so that the transfer material heated to a high temperature. Due to this heat, the temperature of the front end portion of the surface moving body preferentially rises compared to other portions of the separation plate. For this reason, the temperature of the front end portion on the surface moving body side can be quickly increased to a temperature at which dew condensation does not occur, as compared with a conventional separating plate that uniformly increases in temperature, by a transfer material heated to a high temperature. As a result, even when the apparatus is left standing for a long time and the separation plate is cooled, the temperature of the front end portion of the surface moving body can be quickly raised to a temperature at which no condensation occurs, and the occurrence of paper jams can be suppressed. There is an effect that can be.
Hereinafter, an embodiment in which the present invention is applied to a color laser printer (hereinafter simply referred to as “printer”) as an image forming apparatus will be described. FIG. 1 is a schematic configuration diagram of the printer of this embodiment. In this printer, four image forming units of yellow, cyan, magenta, and black are arranged side by side to constitute a tandem image forming unit. In the tandem image forming unit, image forming units 101Y, 101C, 101M, and 101K, which are individual toner image forming units, are arranged in order from the left in the figure. Here, the suffixes Y, C, M, and K of the respective symbols indicate members for yellow, magenta, cyan, and black, respectively. In the tandem image forming unit, the individual image forming units 101Y, 101C, 101M, and 101K are arranged around the drum-shaped photoconductors 21Y, 21C, 21M, and 21K as latent image carriers, and the charging device and the developing device 10Y. , C, M, K, photoconductor cleaning device and the like. At the top of the printer, toner bottles 2Y, 2C, 2M, and 2K filled with yellow, cyan, magenta, and black toners are arranged. Then, each color developing device 10Y, 10C, M, and K is replenished by a predetermined replenishment amount from the toner bottles 2Y, 2C, 2M, and 2K through a conveyance path (not shown).
Further, an optical writing unit 9 as a latent image forming unit is provided below the tandem image forming unit. The optical writing unit 9 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and is configured to irradiate the surface of each photoconductor 1 while scanning with laser light based on image data. .
Further, an intermediate transfer belt 1 in the form of an endless belt is provided as an intermediate transfer member immediately above the tandem image forming unit. The intermediate transfer belt 1 is wound around support rollers 1a and 1b, and a drive motor (not shown) serving as a drive source is connected to a rotation shaft of the drive roller 1a among the support rollers. When this drive motor is driven, the intermediate transfer belt 1 rotates counterclockwise in the figure and the followable support roller 1b rotates. Inside the intermediate transfer belt 10, primary transfer devices 11Y, 11C, 11M, and 11K for transferring toner images formed on the photoreceptors 21Y, 21C, 21M, and 21K onto the intermediate transfer belt 1 are provided.
Further, a secondary transfer roller 5 as a secondary transfer device is provided downstream of the primary transfer devices 11Y, 11C, 11M, and 11K in the driving direction of the intermediate transfer belt 1. A support roller 1b is disposed on the opposite side of the secondary transfer roller 5 and the intermediate transfer belt 1, and functions as a pressing member. Further, a paper feed cassette 8, a paper feed roller 7, a registration roller 6 and the like are provided. Further, a fixing device 4 for fixing an image on the transfer material S and a paper discharge roller 3 are provided downstream of the secondary transfer roller 5 with respect to the traveling direction of the transfer material S on which the toner image is transferred by the secondary transfer roller 5. I have.
Next, the operation of the printer will be described. The photoreceptors 21Y, 21C, 21M, and 21K are rotated by the individual image forming means, and the photoreceptors 21Y, 21C, 21M, and 21K are first rotated by the charging devices 17Y, 17C, 21M, and 21K, respectively. The surfaces of M and K are charged uniformly. Next, the image data is irradiated with writing light by a laser from the optical writing unit 9 to form an electrostatic latent image on the photoreceptors 21Y, 21C, 21M, 21B. Thereafter, toner is attached by the developing devices 10Y, 10C, 10M, and 10K, and the electrostatic latent images are visualized to form yellow, cyan, magenta, and black on the photoreceptors 21Y, 21C, 21M, and 21K, respectively. The monochrome image is formed. Further, the driving roller 1a is rotationally driven by a driving motor (not shown), the other driven roller 1b and the secondary transfer roller 5 are driven to rotate, the intermediate transfer belt 1 is rotated and conveyed, and the visible image is transferred to the primary transfer device. 11Y, C, M, and K are sequentially transferred onto the intermediate transfer belt 1. As a result, a composite color image is formed on the intermediate transfer belt 1. The surface of the photoconductors 21Y, 21C, 21M, and 21K after image transfer is cleaned by removing residual toner with a photoconductor cleaning device to prepare for image formation again.
In accordance with the timing of image formation, the leading edge of the transfer material S is fed from the paper feed cassette 8 by the paper feed roller 7 and conveyed to the registration roller 6 and temporarily stops. Then, the sheet is conveyed between the secondary transfer roller 5 and the intermediate transfer belt 1 while taking timing with the image forming operation. Here, the intermediate transfer belt 1 and the secondary transfer counter roller 5 form a so-called secondary transfer nip with the transfer material S interposed therebetween, and the secondary transfer roller 5 transfers the toner image on the intermediate transfer belt 10 to the transfer material S. Secondary transfer on top.
After the image transfer, the transfer material S is sent to the fixing device 4, where the fixing device 4 applies heat and pressure to fix the transferred image, and is discharged outside the apparatus. On the other hand, the intermediate transfer belt 1 after the image transfer is removed by the intermediate transfer body cleaning device 12 to remove residual toner remaining on the intermediate transfer belt 1 after the image transfer, so that the tandem image forming unit prepares for another image formation.
The toner image forming portions 101Y, 101C, 101M, and 101K for each color are integrally formed to be a detachable process cartridge that can be attached to and detached from the main body. These integral process cartridges can be pulled out toward the front side of the printer body along guide rails (not shown) fixed to the printer body. Further, the toner image forming unit can be loaded at a predetermined position by pushing the process cartridge into the back side of the printer main body.
Here, the process cartridges of the respective toner image forming units 101Y, 101C, M, and K perform the same configuration and operation. Therefore, the subscripts Y, C, M, and K are omitted below, and the process cartridge of the toner image forming unit will be described in detail. FIG. 2 shows an enlarged schematic configuration of the process cartridge of the toner image forming unit 1010. In FIG. 2, a charging roller 17 as a charging device, a developing device 10, a fur brush 36 as a photosensitive member cleaning device, a cleaning blade 33, and the like are sequentially arranged around a photosensitive member 21 that rotates clockwise in the drawing. . As described above, in the printer of this embodiment, the charging roller 17 is disposed vertically below the photoreceptor 21. Further, below the charging roller 17, there is provided a cleaner roller 18 as a charging cleaning roller for cleaning by contacting the surface of the charging roller 17 so as to rotate around. The photoreceptor cleaning device also includes a fur brush 36, a cleaning blade 33, and a waste toner transport coil 34 that discharges waste toner scraped off from the photoreceptor 21 to the outside of the process cartridge.
FIG. 3 is a schematic configuration diagram of the fixing device 4. As shown in FIG. 3, in the fixing device 4, an endless fixing belt 43 as a surface moving body is wound around a heating roller 42 and a fixing roller 41.
Since the fixing belt 43 is heated from the back surface and heated to about 140 to 180 [° C.], it is desirable to use a belt having excellent heat resistance and durability. The fixing belt 43 has a multilayer structure in which an elastic layer is formed on a cylindrical film base made of a heat resistant resin such as polyimide, and a release layer is formed on the elastic layer. The substrate may be a material having heat resistance and mechanical strength, and may be a metal such as Ni or SUS in addition to a heat resistant resin such as polyimide. The elastic layer of the fixing belt 43 may be any material that uniformly applies heat and pressure to the toner and the transfer material in order to obtain stable fixing performance. Examples of the material include silicone rubber and fluororubber. The release layer of the fixing belt 43 is provided in order to suppress a partial offset of the toner image formed on the transfer material, and it is desirable to use a material having excellent toner release properties. Examples of the release layer of the fixing belt 43 include polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene / hexafluoropropylene copolymer (FEP). A fluororesin or a blended material thereof can be used. The release layer made of the material as described above can be obtained by applying and baking the elastic layer via a primer.
In the fixing belt 43 of this embodiment, the thickness of the base is about 50 to 90 [μm], the thickness of the elastic layer is about 100 to 300 [μm], and the thickness of the release layer is about 20 to 50 [μm]. It is said.
The heating roller 42 incorporates a heat source 44 such as a halogen lamp in a metal core such as aluminum or iron, and heats the fixing belt 43 from the inside by this radiant heat. The thinner the core of the heating roller 42, the better. However, in order to receive the tension of the fixing belt, the thickness of aluminum is 0.4 [mm] or more, and the thickness of iron is 0.2 [mm] or more. In addition, a color that easily absorbs heat, such as black, is painted on the inside of the cored bar so that the heat of the heat source 44 can be easily absorbed.
A thermistor 48, which is a temperature sensor element, is disposed on the heating roller 42, and the heating means 44 is controlled so as to reach the set temperature based on the temperature detection of the thermistor 48.
The fixing roller 41 has a structure in which an elastic layer such as silicone rubber is formed on a highly rigid core metal such as a metal such as iron or aluminum or a high-strength resin. The elastic layer is most preferably sponge rubber. By using sponge rubber, the elastic layer can be made to have a low hardness of 50 HS or less (Asker C), and the addition of the fixing belt can be reduced. In addition, since the heat conduction is lower than that of ordinary rubber, it is possible to make it difficult for the heat of the fixing belt to escape.
A tension roller 47 that contacts the fixing belt 43 is provided at an intermediate point between the fixing roller 41 and the heating roller 42. The tension roller 47 pressurizes the belt inward by a spring 47 a, whereby tension is applied to the fixing belt 43. The tension roller 47 covers a metal core having high rigidity such as metal with a material having a certain degree of elasticity such as heat-resistant felt or silicone rubber. By covering the mandrel with silicone rubber, heat-resistant felt or the like, it is possible to prevent the belt from being damaged when the fixing belt 43 is pressed, and to ensure a uniform pressing force. Further, the heat conduction of the tension roller 47 can be made relatively slow as compared with the tension roller using only the core metal, and the heat of the fixing belt 43 can be suppressed from being radiated from the tension roller 47. In this embodiment, the tension roller 47 is in contact with the outer peripheral surface of the fixing belt 43 and presses the fixing belt 43 inward to apply tension to the fixing belt 43. However, the tension roller 47 is not limited thereto. Absent. Tension may be applied to the fixing belt by bringing the tension roller 47 into contact with the inner peripheral surface of the fixing belt and pressing the fixing belt outward. Further, the fixing roller 41 and the heating roller 42 may function as a tension roller. In this case, the fixing roller 41 or the heating roller 42 can be moved, and the fixing belt 43 is pressed outward by the movable fixing roller 41 or the heating roller 42 to apply tension to the fixing belt 43.
Further, a pressure roller 45 is provided as another surface moving member that presses the fixing roller 41 with a biasing means (not shown) such as a spring through the fixing belt 43 to form a fixing nip. The pressure roller 45 has a configuration in which an elastic layer of silicone rubber is formed on a metal core having rigidity such as metal. Further, the elastic layer may be covered with a member having good releasability such as a PFA tube. In addition, the pressure roller 45 increases the hardness of the rubber or the thickness of the elastic layer so that the pressure roller 45 has a higher hardness than the fixing roller 41. When the hardness of the pressure roller 45 is higher than the hardness of the fixing roller 41, the fixing roller 41 is recessed and the fixing nip is curved along the shape of the pressure roller 45. The fixing device 4 of the present embodiment is configured to fix the image on the surface of the transfer material on the side of the fixing belt, and the toner heated and melted in the fixing nip adheres to the fixing belt 43 to fix the transfer material. It tends to adhere to the belt 43. However, since the fixing nip is curved along the shape of the pressure roller 45, the transfer material conveyed to the fixing nip is curved along the shape of the pressure roller 45. For this reason, since the transfer material moves along the pressure roller 45 at the fixing nip exit, the transfer material is easily released from the fixing belt 43 together with the toner. In particular, since a color image has a larger amount of toner on a transfer material than a monochrome image, it easily adheres to a fixing belt. However, by making the hardness of the pressure roller 45 higher than the hardness of the fixing roller 41 as described above, the transfer material can be made difficult to adhere to the fixing belt 43 even for a color image.
Further, the pressure roller 45 is rotated by a driving means (not shown) so that the fixing roller 41 is driven to rotate. In this embodiment, the driving unit is provided on the pressure roller 45, but the driving unit may be provided on the fixing roller 41 and the pressure roller 45 may be driven to rotate.
Further, a release agent application roller 49 is provided in the fixing device 4 so that the melted toner does not adhere to the fixing belt 43. The release agent application roller 49 is in pressure contact with the fixing belt 43 and rotates with the fixing belt 43 to supply the release agent to the fixing belt 43. The release agent application roller 49 is formed of a permeable member such as a sponge, and stores therein, for example, silicone oil as a release agent. In addition, a cleaning roller 50 is provided for removing paper dust and the like adhering to the release agent application roller 49 while being in pressure contact with the release agent application roller 49. The cleaning roller 50 has, for example, a brush-like surface and rotates around the release agent application roller 49. Further, the brush may be made of a conductive member, and paper dust and the like adhering to the release agent application roller 110 may be removed electrostatically.
Further, a separation plate 100 having a leading end portion 101 is provided on the downstream side of the fixing nip in the sheet conveyance direction so that the sheet is not wound around the fixing belt 43. The detailed structure of the separation plate 100 will be described later. The separation plate 100 is disposed so that the tip of the tip 101 and the fixing belt 43 are not in contact with each other and a gap of 1 [mm] or less is formed. When the tip of the tip 101 is arranged so that the tip of the tip 101 contacts the fixing belt 43, the fixing belt 43 may be damaged by the tip of the tip 101, which is not preferable. When the gap between the tip of the tip 101 and the fixing belt 43 exceeds 1 [mm], the transfer material discharged from the fixing nip is caught between the tip of the tip 101 and the fixing belt 43, causing a paper jam. There is a case. Also, the longer the time that the transfer material adheres to the fixing belt 43, the more easily the image becomes uneven. Therefore, the transfer material is separated from the fixing belt 43 at the tip of the tip 101 as soon as possible after leaving the fixing nip. Thus, it is preferable to shorten the time during which the transfer material adheres to the fixing belt 43. For this reason, it is preferable that the tip of the tip 101 is closer to the fixing nip.
Next, a transfer material conveyance path before and after the fixing device will be described. FIG. 4 is a diagram illustrating a transfer material conveyance path before and after the fixing device. As shown in FIG. 4, the transfer material onto which the unfixed toner image on the intermediate transfer belt 10 has been transferred by the secondary transfer roller 5 enters the fixing nip along the entrance guide plate 51. The unfixed toner image on the transfer material that has entered the fixing nip is fixed to the transfer material by pressure and heat. The transfer material that has exited the fixing nip is separated from the fixing belt 43 by the front end portion 101. The separated transfer material is conveyed along the separation plate 100 to the conveyance roller 3 and discharged to a paper discharge tray (not shown).
Next, the separation plate 100 will be described with reference to FIGS. FIG. 5 is a cross-sectional view of the separation plate 100. FIG. 6 is a perspective view showing the peripheral structure of the separation plate 100. As shown in FIG. 5, the separation plate 100 is composed of a tip portion 101 and a guide portion 102.
As shown in FIG. 5, the tip 101 has a tip thickness of 0.2 [mm] or less. In the present embodiment, the thickness of only the tip of the tip is reduced. However, the thickness of the entire tip may be reduced. By reducing the thickness of the tip of the tip part to 0.2 [mm] or less, the tip of the tip part 101 can be disposed closer to the fixing nip. Further, by setting the thickness of the tip portion 101 to 0.2 [mm] or less, it is easy to achieve a temperature (40 ° C. or more) at which the tip portion 101 does not adhere to water vapor due to the heat of the transfer material or the radiant heat from the transfer belt. Can rise to. The tip portion 101 may be formed by crushing the tip of the separation plate 100 to 0.2 [mm] or less with a press or the like, or may be configured by attaching another plate of 0.2 [mm] or less. May be.
The guide unit 102 has a function of guiding the transfer material that has exited the fixing nip to the conveyance roller 3. Further, a case attaching portion 103 is provided on both side surfaces of the guide portion 102, and this case attaching portion is attached to the case of the fixing device. Further, at both ends of the guide portion 102, positioning portions 106 are provided for accurately maintaining a gap between the fixing belt 43 and the tip of the tip portion 101. The positioning portion 106 is provided in the guide portion 102 so as to abut against the transfer material non-contact area of the fixing belt 43. The positioning portion 106 abuts against the transfer material non-contact region of the fixing belt 43, so that the gap between the fixing belt 43 and the tip of the tip portion 101 can be accurately maintained.
The guide part 102 is provided with a heat conduction restricting means. The heat conduction regulating means regulates the conduction of the heat of the tip portion 101 to the guide portion 103 so that the tip portion 101 can easily rise in temperature. Specifically, as shown in FIG. 6, a plurality of rectangular cutout portions 102 a provided in the guide portion 102 and having a large opening function as heat conduction regulating means. In other words, the heat conduction from the tip portion to the guide portion is regulated by providing a large gap between the guide portion and the tip portion by these notches 102a.
The heat conduction regulating means is not limited to the notch. For example, the guide portion and the tip portion may be configured as separate members, and the guide portion and the tip portion may be integrated via a heat insulating material as a heat conduction restricting means. In this way, the heat at the tip portion is not conducted to the guide portion by the heat insulating material, and the temperature at the tip portion can quickly rise to a temperature at which dew condensation does not occur.
In addition, a plurality of reinforcing portions 102 b that reinforce the tip portion 101 are provided between the cutout portions 102 a of the guide portion 102. These reinforcing portions 102b have a function of reinforcing the thin plate-like tip portion 101 so as not to be deformed. The reinforcing portions 102b are preferably provided so as to face both ends of the size of a transfer material that can be used by the printer. In the printer of this embodiment, as shown in FIG. 7, the positions facing the opposite ends of the transfer material of the minimum size that can be used by the printer, and the ends of the transfer material of the maximum size that can be used by the printer. A total of four reinforcing portions 102b are provided at each position. In the printer according to the present embodiment, since the center of the transfer material passes through the center of the fixing belt 43, the reinforcing portions 102b are symmetrical with respect to the center of the fixing belt 43 as shown in FIG. Is provided.
When the transfer material tip is discharged from the transfer nip, it may be unstable such as curling, and the transfer material tip is not necessarily in contact with the tip part 101, but is higher than the tip part 101. May abut against the guide portion. However, even when the transfer material comes into contact with the guide portion, the leading edge of the transfer material comes into contact with the reinforcing portions 102b provided at positions opposite to both ends of the minimum size transfer material that can be used, so that the transfer material can be reliably transferred from the fixing belt. The material can be separated, and the transferability of the transfer material can be maintained.
The width in the axial direction of the reinforcing portion 102b is preferably set corresponding to the positional deviation of the transferred transfer material. In the case of the printer according to the present embodiment, the axial width of the reinforcing portion 102b is set so that the positional deviation of the transfer material by about ± 3 [mm] can be followed from the shape and positional accuracy of the conveyance roller and the like. For this reason, in the case of the printer of this embodiment, the axial width of the reinforcing portion 102b is set to 6 [mm] or more.
Further, since heat is conducted to the reinforcing portion 102b around the reinforcing portion 102b of the tip portion 101, the temperature does not easily rise as compared with other portions, but the reinforcing portion 102b faces the end portion of the transfer material as described above. By providing in the position, the temperature rise around the reinforcement part of the front-end | tip part 101 can be accelerated | stimulated. The reason for this will be described below.
As described above, the temperature of the tip portion 101 rises due to the heat of the transfer material and the radiant heat of the fixing belt 43. The portion of the tip 101 that contacts the transfer material is more likely to rise in temperature due to the heat of the transfer material than the portion that does not contact the transfer material. On the other hand, the temperature of the portion that does not face the transfer material is more likely to rise due to the radiant heat of the fixing belt 43 than the portion that faces the transfer material at the tip 101. This is because the portion of the fixing belt 43 that does not come into contact with the transfer material has a higher temperature than the portion that does not come into contact with the transfer material because heat is not taken away by the transfer material. For this reason, the temperature is likely to rise due to the radiant heat of the fixing belt 43 as compared with the portion of the tip portion 101 facing the transfer material.
The portion of the front end portion 101 facing the end portion of the transfer material is affected by the temperature rise due to the radiant heat having the higher temperature of the fixing belt 43 and the temperature rise due to the contact with the transfer material. The temperature rises more easily than this part. If the reinforcing portion 102b is provided at a position facing the end portion of the transfer material of the tip portion 101 where the temperature tends to rise, the temperature around the reinforcing portion of the tip portion 101 is unlikely to increase due to heat being taken away by the reinforcing portion 102b. It can be suppressed.
Further, as shown in FIG. 8, a heat source 45a is provided inside the pressure roller 45, and the heat source 45a generates heat so that the temperature of the portion facing the reinforcing portion 102b of the heating roller 45 is higher than the temperature of other portions. The amount may be varied in the axial direction. For example, as shown in FIG. 8A, the winding interval of the nichrome wire at the position facing the reinforcing portion 102b of the pressure roller 45 is made narrower than the others. Further, as shown in FIG. 8B, two heat sources 45a are provided, one heat source 45a-1 uniformly heats the entire pressure roller 45, and the other heat source 45a-2 is pressurized. Only the part facing the reinforcement part 102b of the roller 45 is configured to be heated. Thereby, the temperature of the portion of the pressure roller 45 facing the reinforcing portion 102b is higher than that of the other portions. As a result, the temperature around the reinforcing portion of the tip portion 101 is likely to rise due to the radiant heat of the pressure roller 45 compared to other portions. For this reason, even if the heat of the front-end | tip part 101 of a reinforcement part periphery is absorbed by the reinforcement part, the absorbed heat can be supplemented with the radiant heat of the pressure roller 45 whose temperature is higher than another part. As a result, it is possible to suppress the temperature rise around the connecting portion of the tip 101 from becoming difficult compared to others. In FIG. 8, the amount of heat generated by the heat source in the pressure roller is varied in the axial direction in order to increase the temperature of the portion of the pressure roller 45 that faces the reinforcing portion 102 b, but this is not limitative. For example, the amount of heat generated from the heat source 44 in the heating roller 42 may be varied in the axial direction so that the temperature of the portion of the fixing belt 43 facing the reinforcing portion 102b is higher than that of the other portions.
As shown in FIG. 5, the guide portion 102 of the separation plate 100 is provided with a water vapor receiving portion 105 that is inclined toward the fixing roller 46 with respect to a virtual line connecting the guide portion 102 and the tip portion 101. . By inclining the water vapor receiving portion 105 toward the fixing roller, the water vapor receiving portion 105 can be provided at a portion away from the transfer material guide surface of the separating plate 101 by a certain distance. Thereby, the water vapor adhering to the water vapor receiving portion does not adhere to the transfer material. Further, by providing the water vapor receiving portion 105, it is possible to suppress the water vapor generated from the transfer material from adhering to the photoconductor in the apparatus, the lens of the exposure apparatus, and the like and adversely affecting the image.
Further, by inclining toward the fixing roller, the front end portion of the water vapor receiving portion 105 is disposed behind the front end portion 101 with respect to the transfer material guide surface. Thereby, it is possible to suppress the water vapor condensed at the water vapor receiving portion 105 from being dropped onto the tip portion 101 as water droplets. Even if the water vapor of the transfer material adheres to the reinforcing portion, the water vapor of the transfer material does not accumulate so as to condense on the area of the reinforcing portion.
Although the water vapor receiving part 105 shown in FIG. 5 is integrally formed of the same metal as the guide part 102, it may be separated from the guide part 102 as shown in FIG. Further, the water vapor receiving portion 105 shown in FIG. 9 is made of resin, and is made of a member having a lower thermal conductivity than the tip portion 101. As a result, the temperature of the water vapor receiver 105 is unlikely to rise due to the heat in the fixing device, and the water vapor from the transfer material can be easily condensed on the water vapor receiver 105. Thereby, compared with what comprises the same metal as the guide part 102, the water vapor | steam from a transfer material can be collected more.
Furthermore, as shown in FIG. 10, the water vapor receiving portion 105 may be formed by drawing. In this case, the tip of the tip is made thinner and the heat capacity is lowered, so that the temperature of the tip of the separator plate is more likely to rise than other parts. In addition to this, the tip and the guide are separated from each other, and the tip is attached to the guide via a heat insulating material or the like, so that the heat of the tip is conducted to the drawn water vapor receiving part. May be prevented so that the temperature of the tip can be increased satisfactorily.
As described above, according to the fixing device of the present embodiment, the tip portion of the separation plate as the tip portion on the surface moving body side is configured to preferentially rise in temperature compared to other portions of the separation plate. Due to the heated transfer material, the temperature of the tip portion is preferentially increased as compared with other portions of the separation plate. For this reason, the temperature of the tip portion can be quickly raised to a temperature at which no dew condensation occurs due to a transfer material or the like heated to a high temperature, and paper jams can be suppressed.
Further, according to the fixing device of the present embodiment, the heat capacity of the tip is configured to be lower than the other part of the separation plate, and the heat of the tip is conducted to the other part of the separation plate. Heat conduction regulating means for regulating As described above, since the heat capacity of the tip portion is configured to be lower than that of other portions of the separation plate, the temperature of the tip portion can be increased faster than other portions of the separation plate.
Also, if the heat capacity of the tip is lowered to raise the temperature of the tip faster than other parts of the separation plate, and the temperature of the tip becomes higher than the other parts of the separation plate, the heat of the tip is Thermal conduction occurs that travels to other parts of the separator plate. As a result, the speed at which the tip rises to a temperature at which condensation does not occur is slowed down. However, according to the fixing device of the present embodiment, the heat conduction restricting means is provided to restrict the heat at the tip from being conducted to the other part of the separation plate. As a result, even if the temperature at the tip is higher than the other part of the separation plate, the heat at the tip does not conduct to the other part of the separation plate, so the tip quickly rises to a temperature at which condensation does not occur. be able to.
Further, according to the fixing device of the present embodiment, the reinforcing portion is provided so as to face the portion of the surface moving body having a temperature higher than the surface average temperature in the axial direction of the surface moving body at the position facing the tip portion. ing. As for the part where the reinforcement part of the tip part is provided, the heat of the tip part moves to this reinforcement part, so the speed of the rise that rises to a temperature that does not cause condensation compared to the part where the reinforcement part is not provided Becomes slower. As a result, there is a risk that condensation will occur in the portion where the reinforcing portion of the tip portion is provided. However, by having the configuration as described above, it is possible to increase the amount of radiant heat received from the surface moving body of the portion where the reinforcing portion is provided, compared to the portion where the reinforcing portion of the tip portion is not provided. . As a result, the portion provided with the reinforcing portion at the tip can supplement the heat taken away by the reinforcing portion with the radiant heat from the surface moving body. Therefore, it can suppress that the speed which the temperature of the part in which the reinforcement part of the front-end | tip part is provided rises to the temperature which does not produce dew condensation becomes late compared with the part in which the reinforcement part is not provided. Thereby, it can suppress that dew condensation generate | occur | produces in the part in which the reinforcement part of the front-end | tip part is provided.
Further, according to the fixing device of the present embodiment, the heat generation amount of the heat source is adjusted so that the temperature of the portion of the surface moving body facing the reinforcing portion is higher than the surface average temperature in the axial direction of the surface moving body. Different in direction. Thereby, the temperature of the part facing the said reinforcement part of a surface moving body can be made higher than the surface average temperature of the axial direction of a surface moving body.
Further, according to the fixing device of the present embodiment, the reinforcing portion is provided at a position facing the end portion of the conveyed transfer material. The temperature of the portion in contact with the transfer material at the leading end is likely to increase due to the heat of the transfer material, compared to the portion not in contact with the transfer material. On the other hand, the temperature of the portion that does not face the transfer material is more likely to rise due to the radiant heat of the surface moving body than the portion that faces the transfer material at the tip. This is because the portion of the surface moving body that does not come into contact with the transfer material has a higher temperature than the portion that does not come into contact with the transfer material because heat is not taken away by the transfer material. For this reason, the temperature of the portion that does not face the transfer material at the front end is more likely to rise due to the radiant heat of the surface moving body than the portion that faces the transfer material at the front end. For this reason, the portion of the front end facing the end of the transfer material is affected by the radiant heat with the higher temperature of the surface moving body and by the contact of the transfer material. For this reason, as described above, by providing the reinforcing portion at a position facing the end portion of the transfer material being conveyed, the heat deprived by the reinforcing portion is radiated by the higher temperature of the surface moving body and the transfer material. Can be supplemented with heat. Therefore, it can suppress that the speed which the temperature of the part in which the reinforcement part of the front-end | tip part is provided rises to the temperature which does not produce dew condensation becomes late compared with the part in which the reinforcement part is not provided.
Further, according to the fixing device of this embodiment, the separation plate is provided with the water vapor receiving portion, and the water vapor receiving portion is provided at a position where the water condensed at the water vapor receiving portion does not drip onto the tip portion. In this way, the separator plate is provided with a water vapor receiving portion, and the water vapor generated from the transfer material is condensed at the receiving portion, so that the water vapor generated from the transfer material can be obtained by a guide member or a photoconductor provided in the discharge path. It is possible to suppress the occurrence of defects due to condensation. Further, by providing the water vapor receiving portion at a position where the water condensed at the water vapor receiving portion does not drip onto the tip end portion, the water condensed at the water vapor receiving portion at the tip end portion does not drip onto the tip end portion. Therefore, it is possible to prevent the transfer material from adhering to the front end portion due to water adhering to the front end portion and causing a paper jam.
Further, according to the fixing device of the present embodiment, the water vapor receiving portion is provided at a position retracted from the separating portion with respect to the transfer surface of the transfer material. As a result, the transfer material can be prevented from coming into contact with the water vapor receiving part, and the transfer material can be soiled by condensation that has adhered to the water vapor receiving part, or the transfer material can adhere to the water vapor receiving part and cause a paper jam. Can be suppressed.
Further, according to the fixing device of the present embodiment, by forming the water vapor receiving portion with a member having low thermal conductivity, it is difficult for the water vapor receiving portion to rise in temperature, and the temperature at which water vapor generated from the transfer material is condensed. In addition, the temperature of the water vapor receiver can be maintained over time. As a result, it is possible to suppress the problem that water vapor generated from the transfer material is condensed on the photoconductor over time.
Further, according to the image forming apparatus of the present embodiment, since the fixing device having any one of the features (1) to (9) is provided, paper jam can be suppressed.
1 is a schematic configuration diagram illustrating a printer according to an embodiment. FIG. 2 is a schematic configuration diagram of a process cartridge constituting a toner image forming unit of the printer. 1 is a schematic configuration diagram of a fixing device. FIG. 6 is a diagram illustrating a transfer material conveyance path before and after the fixing device. The figure which shows the cross section of a separating plate. The perspective view which showed the periphery structure of the separation plate. The figure which shows the relationship between the size of a transfer material, and arrangement | positioning of a reinforcement part. (A) is a figure which shows an example which changes the amount of heat emitted from the heating means in a pressure roller to an axial direction, (b) is another figure which changes the amount of heat emitted from the heating means in a pressure roller to an axial direction. It is a figure which shows the example of. (A) It is sectional drawing of the separation plate which comprised the water vapor receiving part with another member, (b) is the perspective view which showed the peripheral structure of the separation plate which comprised the water vapor receiving part with another member. The figure which shows the example which formed the water-vapor receiving part by drawing.
DESCRIPTION OF SYMBOLS 1 Printer 4 Fixing device 42 Heating roller 43 Fixing belt 46 Fixing roller 45 Pressure roller 100 Separating plate 101 Tip part 102 Guide part 105 Water vapor receiving part
In order to heat at least one of the surface moving bodies, including two surface moving bodies that are driven to move in the same direction at the nip while abutting each other to form a nip, respectively. A fixing device that heats and fixes the toner image to the transfer material by sandwiching the transfer material on which the unfixed toner image is formed on the surface of the nip.
A separation plate that separates the transfer material that could not be separated from the surface moving body after passing through the nip from the surface moving body; The fixing device is configured to increase the temperature preferentially.
The fixing device, wherein the separation plate is configured such that a heat capacity of the front end portion on the surface moving body side is lower than other portions of the separation plate.
The fixing device according to claim 1 or 2,
The fixing device is characterized in that the separation plate includes a heat conduction restricting means for restricting the heat of the front end portion on the surface moving body side from being conducted to other portions of the separation plate.
The fixing device according to any one of claims 1 to 3,
The separation plate includes a reinforcing portion that reinforces the surface moving body-side tip portion, and has a temperature higher than the surface average temperature in the axial direction of the surface moving body at a position facing the surface moving body-side tip portion. A fixing device comprising the reinforcing portion so as to face the portion.
Fixing characterized in that the amount of heat generated by the heat source is varied in the axial direction so that the temperature of the portion of the surface moving body facing the reinforcing portion is higher than the surface average temperature in the axial direction of the surface moving body. apparatus.
The fixing device according to any one of claims 1 to 5,
The fixing device, wherein the reinforcing portion is provided at a position facing an end portion of a transfer material to be conveyed.
The separation plate includes a water vapor receiving portion that receives water vapor generated from the transfer material, and the water vapor receiving portion is disposed at a position where water condensed at the water vapor receiving portion does not drip onto the front end portion on the surface moving body side. Fixing device to do.
The fixing device, wherein the water vapor receiving portion is provided at a position retracted from the front end portion on the surface moving body side with respect to the transfer surface of the transfer material.
The water vapor receiving portion is formed of a member having low thermal conductivity.
In an image forming apparatus comprising: a toner image forming unit that forms a toner image on a transfer material; and a fixing unit that fixes the toner image on the transfer material.
An image forming apparatus using the fixing device according to claim 1 as the fixing unit.
JP2004347677A 2004-11-30 2004-11-30 Fixing apparatus and image forming apparatus Active JP4264410B2 (en)
JP2004347677A JP4264410B2 (en) 2004-11-30 2004-11-30 Fixing apparatus and image forming apparatus
KR1020067015377A KR100801523B1 (en) 2004-11-30 2005-11-17 Fixing device and image forming apparatus using the same
US10/586,399 US7466949B2 (en) 2004-11-30 2005-11-17 Fixing device having a separation plate
EP20050809324 EP1817641B1 (en) 2004-11-30 2005-11-17 Fixing device and image forming apparatus using the same
DE200560023045 DE602005023045D1 (en) 2004-11-30 2005-11-17 Fixing device and image generating device therewith
CN 200580003449 CN100541350C (en) 2004-11-30 2005-11-17 Fixing device and image forming apparatus using the same
AU2005310749A AU2005310749B2 (en) 2004-11-30 2005-11-17 Fixing device and image forming apparatus using the same
JP2006154560A true JP2006154560A (en) 2006-06-15
JP4264410B2 JP4264410B2 (en) 2009-05-20
JP2004347677A Active JP4264410B2 (en) 2004-11-30 2004-11-30 Fixing apparatus and image forming apparatus
AU (1) AU2005310749B2 (en)
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2004-11-30 JP JP2004347677A patent/JP4264410B2/en active Active
2005-11-17 EP EP20050809324 patent/EP1817641B1/en active Active
2005-11-17 KR KR1020067015377A patent/KR100801523B1/en active IP Right Grant
2005-11-17 US US10/586,399 patent/US7466949B2/en active Active
2005-11-17 CN CN 200580003449 patent/CN100541350C/en active IP Right Grant
2005-11-17 WO PCT/JP2005/021494 patent/WO2006059518A1/en active Application Filing
2005-11-17 AU AU2005310749A patent/AU2005310749B2/en active Active
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AU2005310749A1 (en) 2006-06-08
JP4264410B2 (en) 2009-05-20
DE602005023045D1 (en) 2010-09-30
WO2006059518A1 (en) 2006-06-08
CN100541350C (en) 2009-09-16
EP1817641A4 (en) 2009-07-01
EP1817641A1 (en) 2007-08-15
KR100801523B1 (en) 2008-02-12
EP1817641B1 (en) 2010-08-18
KR20070046781A (en) 2007-05-03
AU2005310749B2 (en) 2009-01-29
US7466949B2 (en) 2008-12-16
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