JP2015191115A - image heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image heating device that suppresses an increase in size of the device, and has both a function to collect a component vaporized from a mold release wax generated by heating of a toner image and a shutter function to shield a conveyance path of a recording material.SOLUTION: A collection member collecting a wax component can move between a first position to open a conveyance path of a recording material and a second position to shield the conveyance path of a recording material.

Description

  The present invention relates to an image heating apparatus used in an image forming apparatus employing an image forming process such as an electrophotographic system or an electrostatic recording system, such as a copying machine or an LBP. As an image heating device, a fixing device that heats and fixes an unfixed toner image formed on a recording material as a fixed image, or a glossiness increasing device that increases the glossiness of an image by heating the image fixed on the recording material Etc.

  In a general electrophotographic image forming apparatus, an electrostatic latent image is formed on the surface of a photosensitive drum as an image carrier based on image information. Then, the electrostatic development on the photosensitive drum is visualized with a developer such as toner, and the developed image is transferred onto the recording material as an unfixed image by a transfer unit. The recording material on which the image has been transferred is sent to a fixing device, and the unfixed image is fixed by pressure, heat, or the like. As the fixing device, a contact-type fixing device such as a film heating method or a heat roller method is used.

  In these contact-type fixing devices, the phenomenon of offset is unavoidable. That is, a phenomenon in which a toner image is electrostatically transferred to a fixing film or a heat roller when an unfixed toner image is fixed by a fixing device.

  For the offset phenomenon, it is one of the effective measures to improve the releasability of the toner on the surface of the fixing film or the heat roller, and in order to realize this, a release wax made of a hydrocarbon compound or the like Toners have been proposed and put into practical use.

  When using toner containing these release waxes, the release wax is liquefied by heating when the toner is fixed. Further, a part of the liquefied release wax is vaporized and then floats inside the machine in a solidified state and adheres at various points in the machine.

  As a result, if the release wax component adheres to the conveyance guide of the recording material, it becomes resistance to conveyance of the recording material, and if it adheres to the conveyance roller, it lowers the friction coefficient of the roller, thereby reducing the conveyance performance. This may cause problems such as jamming of the recording material.

  In view of this, as one of countermeasures against the problems associated with the adhesion of the release wax component, it has been proposed to provide a collection member for collecting the release wax in the fixing device (Patent Document 1). In this method, by keeping the temperature of the collecting member at a temperature at which the release wax is liquefied, the release wax floating in a solidified state is reliquefied by the collection member and adsorbed.

The collecting member preferably has its own heat source because temperature management is required. However, it is not realistic from the viewpoint of cost and space. For this reason, it is practical to adopt a configuration in which the temperature of itself is raised using the heat of the heating rotator (fixing film or heat roller), and the configuration proposed in Patent Document 1 adopts a similar configuration. Yes.

JP 2010-249874 A

  When using the heat of such a heating rotator to raise the temperature of itself and perform optimal temperature control, the heat capacity of the collecting member determined by the material and volume of the collecting member, and the heating rotator serving as the heat source Distance is important. For this reason, a certain occupied volume is required in the vicinity of the heating rotator.

  By the way, the image forming apparatus needs to open the door so that the user can access the paper transport surface because of the necessity of handling the jamming of the recording material. At this time, it is preferable to be configured so that the vicinity of the fixing unit can be accessed. However, if the user's fingertip can contact the surface of the heating rotator and the pressure roller, the surface of the heating rotator is particularly damaged, This can cause dents.

  In order to prevent such a situation, it is effective to provide a shutter (fixing shutter) as shown in FIG. That is, when accessing the vicinity of the fixing unit by jam processing or the like, the shutter 460 covers the upstream conveyance path of the nip portion (FIG. 11 (a2)). On the other hand, after the work is completed, the shutter 460 is retracted to at least a position that does not hinder the conveyance of the media.

  However, when the collecting member and the shutter 460 are used in combination, it is desirable that both of them are arranged in the immediate vicinity of the fixing unit.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image heating apparatus having a function of collecting vaporized components from a release wax generated by heating of a toner image and a shutter function of shielding a recording material conveyance path while suppressing an increase in size of the apparatus. Is to provide.

  In order to achieve the above object, an image heating apparatus according to the present invention sandwiches and conveys a heating rotator and a recording material carrying a toner image formed using a toner containing wax together with the heating rotator. A counter member that forms a nip portion that heats the toner image, and a collecting member that collects components evaporated from the wax by being heated in the nip portion, and radiant heat from the heating rotator And a collecting member that raises the temperature of the component to a temperature at which the component is in a liquid phase state. In the image heating apparatus, the collecting member opens a conveyance path of the recording material at a first position. And a second position where the recording material conveyance path is shielded.

  According to the present invention, the function of collecting or retaining the vaporized component from the release wax generated by heating the toner image within a limited volume and the shutter function of shielding the recording material conveyance path are well combined. An image heating apparatus can be provided.

(A1), (a2) is sectional drawing which respectively shows the 1st position and the 2nd position of the collection member in the fixing device as an image heating apparatus concerning the 1st Embodiment of this invention. 1 is a schematic cross-sectional view showing an overall configuration of an image forming apparatus equipped with a fixing device as an image heating device according to an embodiment of the present invention. (A) is a perspective view which shows the structure of the fixing device concerning 1st Embodiment, (b) (c) is an enlarged view of the W1 part. (B1) and (b2) are side views of the fixing device according to the first embodiment as seen from the directions indicated by arrows a and b in FIG. 3 (a), respectively. FIG. 9 is a perspective view illustrating a configuration of a fixing device according to a second embodiment. (A1), (a2) is sectional drawing which shows the 1st position and 2nd position of the collection member in the fixing device concerning 2nd Embodiment, respectively. (B1) and (b2) are side views showing a first position and a second position of the collecting member in the fixing device according to the second embodiment, respectively. FIG. 9 is a perspective view illustrating a configuration of a fixing device according to a third embodiment. (A1), (a2) is sectional drawing which shows the 1st position and 2nd position of the collection member in the fixing device concerning 3rd Embodiment, respectively. (B1) and (b2) are side views showing a first position and a second position of the collecting member in the fixing device according to the third embodiment, respectively. (A1), (a2) is the figure which showed the mode of the closing / opening interlocking | linkage of the conventional fixing shutter.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<< First Embodiment >>
(Image forming device)
First, an image forming apparatus equipped with a fixing device as an image heating apparatus according to an embodiment of the present invention will be described along the flow of a sheet S as a recording material with reference to FIG. FIG. 2 is a schematic cross-sectional view of an image forming apparatus (laser beam printer using a transfer type electrophotographic process) equipped with an image heating apparatus according to an embodiment of the present invention. The image forming apparatus 1 forms an image by an electrophotographic method. The sheet S is conveyed to the image forming means 4 by a feeding and conveying unit to transfer a toner image, and the sheet S is conveyed to the fixing device 100. After the toner is fixed, the toner is discharged to a discharge tray 8 which is a discharge portion.

  Reference numeral 41 denotes an electrophotographic photosensitive drum (hereinafter referred to as a drum) as an image carrier in the image forming unit, which is rotationally driven at a predetermined peripheral speed (process speed). P is a process cartridge provided in the housing 4. The charging unit performs charging processing on the surface of the drum 41, the developing unit that visualizes the electrostatic latent image on the drum 41, and the residual toner image on the drum 41. A cleaning means for removing and collecting is integrally provided.

  Reference numeral 5 denotes a laser beam scanner as image exposure means. Corresponding to the time-series electric digital pixel signal of the target image information input from an external device such as an image scanner / computer (not shown), an on / off modulated laser beam is output, and the charged surface of the drum 41 is scanned and exposed. (Irradiate). By this scanning exposure, the charge of the exposed bright portion on the surface of the drum 41 is eliminated, and an electrostatic latent image corresponding to the target image information is formed on the surface of the drum 41.

  Here, the sheet feeding roller 21 is driven based on the sheet feeding start signal, and the sheets S in the sheet feeding cassette are separated and fed one by one. Then, the toner passes through the registration roller 3 and is introduced at a predetermined timing into a transfer portion which is a contact nip portion between the transfer roller 42 and the drum 41. That is, when the leading edge of the toner image on the drum 41 reaches the transfer site, the registration roller 3 controls the conveyance of the sheet S so that the leading edge of the sheet S also reaches the transfer site.

  A transfer voltage (transfer bias) controlled to a predetermined level from a transfer bias application power source (not shown) is applied to the transfer roller 42, and the toner image on the drum 41 is electrostatically transferred onto the surface of the sheet S at the transfer site.

  The sheet S that has received the transfer of the toner image at the transfer site is separated from the drum 41 and conveyed to a fixing device 100 as an image heating device, where the toner image is subjected to heating and pressure fixing processing. The sheet S that has passed through the fixing device 100 is discharged to the outside by the discharge roller pair 7 via the sheet discharge path 6 and is stacked on the discharge tray 8.

(Fixing device as an image heating device)
Next, the fixing device 100 as the image heating device according to the embodiment of the present invention will be described. In FIG. 1, fixing is performed by a heating unit 101 including a fixing film 105 as an endless belt, a ceramic heater as a heating source disposed in contact with the inner surface of the fixing film, and a pressure roller 102 in pressure contact therewith. A nip portion N is formed. The sheet S is nipped and conveyed by the fixing nip portion N, and passes through the fixing nip portion N, whereby the carried unfixed toner image is fixed.

  With respect to the heating unit 101, as shown in FIG. 1A 1, the heater 103 as a heating source, the heater holder 104 that supports the heater 103, and the outer periphery of the heater holder 104 are rotated and brought into direct contact with the sheet S. It has a fixing film 105 that conducts heat. A pair of fixing flanges 106 are provided as support members for the fixing film 105 at both ends in the longitudinal direction of the fixing film 105 as a film-like heating rotating body (first rotating body that is a fixing rotating body). The pair of fixing flanges 106 serves as a guide member for the rotation locus of the fixing film 105 and supports the fixing film 105.

  The fixing flange 106 also supports the heater holder 104, and also has a role of supporting the entire heating unit 101 on a fixing frame 107 as a casing. The fixing frame 107 that supports the fixing flange 106 so as to be movable in the pressurizing direction is in contact with the outer peripheral surface of the fixing film 105, and a pressurizing rotating body (second rotation) as a pressurizing body that backs up the heater holder 104. Body, opposite body) is supported. Here, on the inner side of the fixing film 105, a pressure applying member 110 (iron stay) is provided as a backup member in contact with the inner peripheral surface of the fixing film 105.

  Here, the heating unit 101 and the pressure roller 102 in pressure contact therewith are provided so as to extend in the direction perpendicular to the paper surface (longitudinal direction) in FIG. FIG. 3A is a perspective view illustrating a configuration of the fixing device 100. The positional relationship in the pressing state of the fixing nip portion N during paper conveyance is shown. FIG.3 (b) is an enlarged view of the W1 part in Fig.3 (a). For convenience of explanation, the position at the time of releasing the nip pressure during non-paper conveyance, such as during jam processing, is illustrated.

  1 (a1) to (a2) and FIGS. 4 (b1) to (b2) show the relationship between the fixing film 105 and the collecting member 109 in the fixing device 100 in the directions indicated by arrows a and b in FIG. Sectional drawing and side view are shown. As will be described in detail later, FIG. 1A1 shows a first position for collecting the release wax in the nip pressure state of the heating unit 101, and FIG. 1A2 protects the fixing film 105 in the nip pressure release state. The second position is shown. Note that FIGS. 1A1 and 1A2 show the postures of the collecting member 109 and the tip 109c thereof.

  4 (b1) and 4 (b2) show the posture of the pressure release cam 111 at the same timing as that in FIGS. 1 (a1) and (a2), respectively. In the present embodiment, the heating unit 101 is configured to be pressurized in the direction of arrow F by a pressure spring 108 via a pressure plate 112, as shown in FIG. 4 (b1).

  The heating unit 101 is linked to a movable part outside the fixing device 100 (operating during jam processing such as opening / closing operation of a door (not shown) for taking out the process cartridge (hereinafter referred to as CRG door)). The pressure roller 102 can be released from pressure by rotating the pressure release shaft 113 and the pressure release cam 111 and pushing up the pressure plate 112 by the force received through the movable part.

(Components evaporated from release wax caused by heating of toner image and countermeasures)
The fixing nip N fixes the toner image on the sheet S by heating while nipping and conveying the sheet S carrying the toner image formed using the toner containing the release wax.

(Releasable wax collecting section that also serves as a fixing shutter)
The collection member 109 as the release wax collection unit according to the embodiment of the present invention moves to the following first position and second position. Here, the first position is a position for collecting components vaporized from the release wax generated by heating the toner image in a state where the conveyance path of the recording material is opened. The second position is a position that blocks the conveyance path of the recording material.

  The collecting member 109 which is such a moving member has a shape in which the direction perpendicular to the recording material conveyance direction is the longitudinal direction. Further, it has an arc shape in a cross section orthogonal to the longitudinal direction. The collecting member 109 also serves as a fixing shutter, and can rotate on the outer peripheral side of the heating unit 101 as shown in FIG. In the first position (FIG. 1 (a1)) where the recording material conveyance path is opened, the recording material functions as a collecting unit for collecting the release wax. On the other hand, the front end 109c functions as a fixing shutter at the second position (FIG. 1 (a2)) where the recording material conveyance path is blocked.

1) Material of Release Wax Collection Part Here, the collection member 109 as the release wax collection part is formed of a resin material (high affinity with the release wax component) such as PBT or PET, and is vaporized. The released release wax component is collected.

2) Arrangement of Release Wax Collection Portion As shown in FIG. 4, the collection member 109 is slidable by engaging the arc rib 109 b of the collection member 109 with the arc groove 107 b of the fixing frame 107 ( It can be rotated). Here, the collecting member 109 is arranged on the outer peripheral side with respect to the fixing film 105 so that when the heating unit 101 is heated, its temperature is raised to a temperature at which the release wax component becomes a liquid phase. It has a portion arranged at a position separated by a certain distance t (FIG. 1 (a1)). In the present embodiment, the collection member 109 is disposed at a position where all the portions are separated by a certain distance t on the outer peripheral side.

  And it heats by the radiant heat from the fixing film 105 as a heating rotary body, and it can collect a wax component using wetness because the collection member 109 becomes the temperature which a mold release wax maintains a liquid phase state.

  With respect to the constant distance t, in this embodiment, as shown in FIG. 4B1, the arc center of the arc groove 107b is set to the virtual rotation center of the fixing film 105 (the fixing film 105 is fixed to the pressure roller 102 and the fixing nip portion N). And a state in which the sheet S is conveyed). As a result, the distance between the fixing film 105 and the collecting member 109 is set to be t. That is, the predetermined distance t can be managed relatively easily by determining the positions of related parts with respect to the fixing frame 107 (arc groove 107b).

2) Operation of Release Wax Collection Unit As described above, the collection member 109 as the release wax collection unit according to the present embodiment can rotate on the outer peripheral side of the heating unit 101. And in the 1st position (FIG. 1 (a1)) which collects release wax in the state where the conveyance path of the recording material was opened, it functions as a collection part which collects release wax. On the other hand, when the nip pressure is released, the leading end 109c functions as a fixing shutter in the second position (FIG. 1 (a2)) where the recording material conveyance path is shielded to protect the fixing film.

  Specifically, the collecting member 109 has a groove portion of the cam 114 (FIG. 3C) provided at the longitudinal end portion by the shaft portion 109a (FIGS. 1A1 and 1A2) at the longitudinal end portion. 114a (FIG. 1 (a1), (a2)) is slidably engaged. Further, the collecting member 109 is slidably engaged with the arc groove 107b of the fixing frame 107 by the protrusion 109b (FIG. 3B).

  Here, the cam 114 is fixed to the pressure release shaft 113 to which the pressure release cam 111 (FIG. 3C) is fixed. When the pressure release cam 111 rotates around the pressure release shaft 113 from the state of FIG. 1 (a1) or FIG. 1 (b1), the cam 114 and the collection member 109 (shaft portion 109a) rotate synchronously. The leading end 109c also serving as the fixing shutter also rotates along the arc groove 107b.

  That is, as shown in FIG. 3C, since the pressure release cam 111 and a cam 114 described later are provided with the pressure release shaft 113 as a common shaft, the collection functioning as a fixing shutter at the second position. The member operates in synchronization with the pressure release mechanism used when the heating rotator is separated. In this way, the leading end 109c of the collecting member 109 can move to the second position that shields the immediate upstream of the fixing nip N of the sheet S conveyance path (FIG. 1 (a2)). In order to return to the original position, the reverse procedure described above is followed.

(Effect of this embodiment)
As described above, according to the present embodiment, the collecting member can be relatively easily positioned at the predetermined distance t with respect to the fixing film, which is a heat source for raising the temperature of the recording member during conveyance of the recording material, and fixing. It can also be used as a shutter.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 5A is a perspective view showing a configuration of a fixing device 200 as an image heating device in the present embodiment, and FIGS. 6 and 7 show a relationship between a fixing film and a collecting member / fixing shutter in the fixing device 200. FIG. The difference from the first embodiment is that the collecting member 209 of the configuration of the fixing device 200 has a gear portion 209 a, is fixed to a rotating shaft 113 that is rotatably supported by the fixing frame 207, and interlocks with the gear 214. It is a point that rotates. The parts having the same configuration and function as those of the first embodiment are denoted by the same numbers as those of the first embodiment, and the description thereof is omitted.

  With respect to the fixing device 200 of the present embodiment, as shown in FIG. 5B, the fixing frame 207 to which the collecting member 209 that also serves as a fixing shutter is attached is shown in FIG. 6A2. An arc-shaped arc rib 207b for guiding the moving direction is provided. The collection member 209 is slidably engaged with the arc rib 207b by the arc groove 209b. The arc rib 207b is integrally fixed to the fixing frame 207 by means such as caulking (not shown).

  Here, the arc center of the arc rib 207b is the same as the virtual rotation center of the fixing film 105 (a state in which the fixing film 105 forms the fixing roller nip N with the pressure roller 102 and conveys the sheet S). Accordingly, the fixing film 105 and the collecting member 209 are arranged such that the distance is t. In this way, the position of the related component relative to the fixing frame 207 is determined, and the predetermined distance t can be managed relatively easily.

  Hereinafter, the operation of the collecting member 209 will be described. FIG. 6 (a1) shows a first position for collecting the release wax in the nip pressure state of the heating unit 101, and FIG. 6 (a2) shows a second position for protecting the film in the nip pressure release state. Show. FIGS. 7B1 and 7B2 are side views of the same timing as FIGS. 6A1 and 6A2, respectively.

  Here, when the pressure release cam 111 fixed to the shaft 113 in FIG. 7B1 rotates in the direction of the arrow in FIG. 7B, the gear 214 fixed to the same shaft 113 (FIG. 5B) synchronizes. Rotate in the direction of the arrow in the figure. The gear 214 is engaged with the tooth surface of the collecting member 209. The collecting member 209 rotates along an arc groove 209b that engages with the arc rib 207b. With the rotation, the leading end portion 209c of the collecting member 209 is located in the immediate vicinity of the fixing nip portion N with the upstream side serving as a fixing shutter. Shield. It should be noted that when the upstream fixing shutter is opened in the immediate vicinity of the fixing nip portion N, the above operation is performed in the reverse direction.

<< Third Embodiment >>
Next, a third embodiment of the present invention will be described with reference to FIGS. In the first and second embodiments, the collecting member moves to the first position and the second position. In this embodiment, a retention member that retains the component vaporized from the release wax in the fixing device is also used as the fixing shutter. The staying member retains the vaporized component in the fixing device and suppresses adhesion to the conveying roller or the like. In addition, in this embodiment, about the component which comprises the same structure and function as 1st, 2nd embodiment, the description is omitted by attaching | subjecting the same number as 1st, 2nd embodiment.

  In the present embodiment, the stay member 309 that is a component of the fixing device 300 moves so as to have a linear movement locus instead of an arc shape. That is, with respect to the fixing device 300, as shown in FIG. 8B, the fixing frame 307 to which the staying member 309 serving also as a fixing shutter is attached guides the moving direction of the staying member 309 as shown in FIG. 9A1. It has a linear guide rib 307b. The guide rib 307b is formed integrally with the fixing frame 307 by means such as caulking (not shown).

  Here, when the pressure release cam 111 rotates around the pressure release shaft 113 shown in FIG. 8B, the cam 314, the cam follower 309a, and the groove 309b move along the linear guide rib 307b in synchronization. The tip 309c that also serves as the shutter moves in the same manner. As a result, the front end portion 309c of the stay member 309 shields the upstream side in the immediate vicinity of the fixing nip portion N and functions as a fixing shutter. The cam follower portion 309a (FIG. 9) of the stay member 309 is biased upward in the figure by the spring 320.

  FIG. 9 (a1) shows a first position where a space for retaining the release wax is formed in the nip pressure state of the heating unit 101. FIG. FIG. 9A2 shows a second position where the fixing film is protected by shielding the recording material conveyance path in the nip pressure release state. FIGS. 10B1 and 10B2 show interlocking states at the same timing as those in FIGS. 9A1 and 9A2, respectively.

  As described above, according to the present embodiment, the same effects as those of the first and second embodiments can be obtained, and the fixing device can be downsized because it is not necessary to take a large arrangement area of the staying member. Become.

(Modification)
In the first and second embodiments described above, the configuration in which the collecting member is moved to the recording material inlet side of the nip portion is shown, but a configuration in which the collecting member is moved to the outlet side may be used.

  Although the preferred embodiments of the present invention have been described in the above-described embodiments, the present invention is not limited to these embodiments, and various modifications are possible within the scope of the gist.

102 ..Pressure roller, 105 ..Fixing film, 109, 209 ..Collecting member (also fixing shutter), 309 ..Standing member, N ..Fixing nip, S ..Recording material (sheet material)

Claims (10)

A heating rotor,
A counter body that forms a nip portion that heats the toner image by sandwiching and conveying a recording material carrying a toner image formed using toner containing wax together with the heating rotator;
A collecting member that collects a component vaporized from the wax by being heated at the nip portion, and is heated by radiant heat from the heating rotating body so that the component becomes a liquid phase state. A collecting member for raising the temperature;
In an image heating apparatus having
The image heating apparatus, wherein the collecting member is movable to a first position where the recording material conveyance path is opened and a second position where the recording material conveyance path is shielded.   2. The movement of the collection member from the first position to the second position is synchronized with a pressure release mechanism used when the heating rotator is separated from the opposing body. The image heating apparatus as described.   The said collection member in a said 1st position has a part maintained by the temperature from which the component vaporized from the said wax by the radiant heat from the said heating rotary body will be in a liquid phase state is characterized by the above-mentioned. The image heating apparatus described in 1.   4. The image heating according to claim 1, wherein the collection member at the first position has a portion in which a distance from the heating rotator is kept constant. 5. apparatus.   5. The image heating apparatus according to claim 1, wherein the collecting member has a shape in which a direction orthogonal to a conveyance direction of the recording material is a longitudinal direction. 6.   The image according to any one of claims 1 to 5, wherein a movement locus of the collecting member between the first position and the second position is an arc shape or a straight line shape. Heating device. A support member for supporting the heating rotator;
A housing that supports the support member so as to be movable in the pressurizing direction;
A backup member in contact with the inner peripheral surface of the heating rotator,
The image heating apparatus according to claim 1, comprising:   The image heating apparatus according to claim 7, wherein the collection member is positioned with respect to the casing or the support member.   The image heating apparatus according to claim 1, wherein the heating rotator is an endless belt heated by a heating source.   The image heating apparatus according to claim 1, wherein the opposing body is a pressure roller.