JP6922203B2 - Fixing device and image forming device - Google Patents

Description

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

Conventionally, in an image forming apparatus that employs an electrophotographic method, paper on which an unfixed toner image is transferred is conveyed to a nip portion between a heating roller heated by a heat source and a pressure roller that presses against the heating roller to heat and apply the unfixed toner image. It is widely practiced to melt and fix an unfixed toner image on paper by pressing.

In such a fixing device, the pressure roller may become hot due to the heat transfer from the heating roller. When forming an image on both sides of the paper, if the fixed toner image on the first side comes into contact with a high-temperature pressure roller when the unfixed toner image on the second side is fixed, image noise such as a gloss step appears on the fixed toner image on the first side. There is a problem that it occurs and the image quality deteriorates.

In order to prevent this image noise, various fixing devices having a cooling unit that cools the pressurizing roller by the wind of a fan when the temperature rises above a predetermined temperature have been proposed. For example, Patent Document 1 proposes a fixing device that cools a pressurizing member by the wind of a cooling fan.

On the other hand, it is known that silicon rubber and toner used in heating rollers and fixing belts release UFP (Ultra Fine Particulates) by heat at the time of fixing. Therefore, there is a technique in which the air in the fixing device is sucked by a fan so that the UFP is not discharged to the outside of the device, the UFP is removed by a filter, and then the air is discharged to the outside of the device. For example, Patent Document 2 proposes to control the operation of a recovery fan so that UFP can be recovered under the initial burst condition in which a large amount of UFP is generated.

However, in the method of sucking the air in the fixing device by a fan to recover the UFP, the temperature of the heating roller may decrease due to the air flow generated by the fan. Therefore, in Patent Document 3, in order to prevent the temperature of the heating roller and the pressurizing roller from dropping, it is proposed to generate an air flow for recovering UFP only at the end of the roller where a large amount of UFP is released.

Japanese Unexamined Patent Publication No. 2010-20451 Japanese Unexamined Patent Publication No. 2011-180341 Japanese Unexamined Patent Publication No. 2010-134133

However, it is possible to achieve both cooling the pressure roller to prevent image noise such as a glossy step, generating an air flow to recover the UFP generated from the fixing member, and suppressing the temperature drop of the heating roller. I haven't done enough yet.

The present invention has been made in view of such a conventional problem, and when the temperature of the heating roller is not lowered as much as possible when the pressure roller is cooled and the amount of UFP generated is large such as during warm-up, UFP is generated. An object of the present invention is to provide a fixing device and an image forming device capable of increasing the amount of recovery.

The fixing device according to the present invention that achieves the above object includes a heating member heated by a heating source and a pressurizing member that presses against the heating member, and toner is applied to a nip portion between the heating member and the pressurizing member. A fixing device that passes a recording material on which an image is formed to fix a toner image on the recording material, and is a cooling means for generating a flow of air toward the pressurizing member to cool the pressurizing member, and the heating. A first exhaust passage having a first intake port at a predetermined position facing the longitudinal direction of the member or the pressurizing member, and a second exhaust passage having a second intake port in the vicinity of both ends in the longitudinal direction of the heating member. The exhaust means for discharging the air flowing in from the first intake port and the second intake port to the outside from the main body of the apparatus through the first exhaust passage and the second exhaust passage, and the air generated by the cooling means press the heating member. It is characterized by including a cooling suppressing means for suppressing cooling and a control unit for operating the cooling suppressing means while the cooling means is operating.

In the fixing device having the above configuration, the cooling suppressing means is a first shutter member that can move between a closed position that closes the first intake port and an open position that opens the first intake port, and the control unit is the first while the cooling means is operating. 1 The shutter member may be in the closed position. At this time, the cooling means may be located on the pressurizing member side when viewed from the nip portion, and the first intake port may be located on the heating member side when viewed from the nip portion.

Further, in the fixing device having the above configuration, the cooling suppressing means is a second shutter member that can move to a closed position that prevents the air generated by the cooling means from heading toward the heating member and an acceptable open position. The control unit may be configured such that the second shutter member is in the closed position during the operation of the cooling means. At this time, the second shutter member is a plate-shaped member that is long in the longitudinal direction of the pressurizing member, is located in the vicinity of the pressurizing member, and swings around an axis substantially parallel to the longitudinal direction of the pressurizing member. It moves to prevent or tolerate the air generated by the cooling means toward the heating member, and the cooling means and the first intake port are opposite to the nip portion when viewed from the installation position of the second shutter member. It may be configured to be located on the side of.

Further, in the fixing device having the above configuration, a temperature detecting member for detecting the temperature of the pressurizing member is further provided, and the control unit operates the cooling means when the temperature measured by the temperature detecting member becomes equal to or higher than a predetermined temperature. It may be configured.

Further, in the fixing device having the above configuration, the control unit may have a configuration in which the first shutter member or the second shutter member is in the open position while the cooling means is not operating.

Further, in the fixing device having the above configuration, the control unit may be configured to deactivate the cooling suppressing means at the time of warming up. In addition, in this specification, "warm-up" means raising a temperature of a heating member to a target temperature.

Further, in the fixing device having the above configuration, the control unit may be configured to increase the exhaust amount by the exhaust means at the time of warming up as compared with the normal operation.

Further, according to the present invention, there is provided an image forming apparatus including the fixing apparatus according to any one of the above.

According to the fixing device according to the present invention, when it is necessary to cool the pressurizing member, the pressurizing member can be cooled without lowering the temperature of the heating member as much as possible, and the amount of UFP generated during warm-up or the like. When there are many UFPs, UFP can be recovered efficiently.

It is a schematic block diagram which shows the internal structure of the image forming apparatus of this invention. It is a vertical cross-sectional view which shows the structure of the fixing device in the image forming apparatus of 1st Embodiment of this invention. It is sectional drawing of the fixing apparatus 6a seen from the direction of arrow A of FIG. It is a perspective view which shows the 1st shutter member 71 and its moving mechanism. It is a vertical cross-sectional view of the fixing device 6a at the time of cooling of a pressure roller 62. It is sectional drawing of the fixing apparatus 6a seen from the direction of arrow A of FIG. It is a vertical cross-sectional view of the fixing device 6a at the time of a normal time and a warm-up time. It is sectional drawing of the fixing apparatus 6a seen from the direction of arrow A of FIG. It is a vertical cross-sectional view which shows the structure of the fixing device 6b of the 2nd Embodiment of this invention. 9 is a cross-sectional view of the fixing device 6b seen from the direction of arrow A in FIG. It is a perspective view which shows the 2nd shutter member 76a and the rocking mechanism thereof. It is a vertical cross-sectional view of the fixing device 6b at the time of cooling of a pressure roller 62. It is sectional drawing of the fixing apparatus 6b seen from the direction of arrow A of FIG. It is a vertical cross-sectional view of the fixing device 6b at the time of a normal time and a warm-up time. It is sectional drawing of the fixing apparatus 6b seen from the direction of arrow A of FIG.

Hereinafter, the present invention will be described in more detail with reference to the drawings, but the present invention is not limited to these embodiments.

(First Embodiment)
FIG. 1 is a diagram showing an overall configuration of an image forming apparatus 1 as an embodiment of the image forming apparatus according to the present invention. The vertical direction, the horizontal direction, and the paper surface depth direction in FIG. 1 are the vertical direction, the horizontal direction, and the front-rear direction of the image forming apparatus.

The image forming apparatus 1 is a so-called multifunction device (MFP: Multifunction Peripheral) capable of executing a copy job, a print job, a scan job, a fax job, and a box job. The box job is a job executed by using the data stored in the box (folder) included in the image forming apparatus 1.

The image forming apparatus 1 is mainly composed of an image forming unit 2, an automatic document conveying unit 3, a document reading unit 4, and a paper feeding unit 5, and executes image forming based on print settings. A print setting is a set of setting values corresponding to a plurality of setting items related to image formation.

The automatic document transporting unit 3 automatically transports the document placed on the platen to the reading position of the document reading unit 4.

The document scanning unit 4 reads the image of the document transported by the automatic document transporting unit 3 and generates scanning data.

The paper feed unit 5 includes a plurality of paper feed trays 51a to 51c, and supplies the paper as a recording material housed in the respective paper feed trays 51a to 51c to the image forming unit 2.

The image forming unit 2 forms an image on the paper supplied by the paper feeding unit 5 based on the reading data generated by the document reading unit 4 or the print data acquired by the data IF (Interface) unit described later.

The image forming unit 2 corresponds to each of Y (yellow) color, M (magenta) color, C (cyan) color, and K (black) color (hereinafter, may be indicated as Y color to K color). A photoconductor 81, a charging unit 82, an image exposure unit 83, a developing unit 10, a primary transfer unit 11, and a cleaning unit 12 are provided. Further, the image forming unit 2 includes an intermediate transfer body 13, a resist roller pair 14, a secondary transfer unit 15, and a fixing device 6a, which are common to colors Y to K.

Hereinafter, the photoconductor 81, the charging unit 82, the image exposure unit 83, the developing unit 10, the primary transfer unit 11, and the cleaning unit 12 corresponding to the Y color will be described. The charging unit 82 charges the photoconductor 81. The image exposure unit 83 forms an electrostatic latent image on the charged photoconductor 81 by irradiating it with laser light. The developing unit 10 develops a toner image corresponding to the electrostatic latent image formed on the photoconductor 81 on the photoconductor 81. The primary transfer unit 11 primary transfers the toner image developed on the photoconductor 81 to the intermediate transfer body 13. The cleaning unit 12 removes the toner remaining on the photoconductor 81 without being transferred to the intermediate transfer body 13 from the photoconductor 81.

The timings of the photoconductor 81, the charging unit 82, the image exposure unit 83, the developing unit 10, the primary transfer unit 11, and the cleaning unit 12 corresponding to the M to K colors are also adjusted so that the toner images of the corresponding pixels overlap. At the same time, the same operation as the above-mentioned Y color is performed, and a toner image of Y color to K color is formed on the intermediate transfer body 13.

The resist roller pair 14 corrects the skew of the paper supplied from the paper feeding unit 5, adjusts the timing so that the toner image transferred on the intermediate transfer body 13 comes to a predetermined position on the paper, and sets the paper to 2. It is conveyed to the next transfer unit 15. The secondary transfer unit 15 secondarily transfers the toner image on the intermediate transfer body 13 onto the paper.

The fixing device 6a fixes the toner image transferred on the paper. The fixing device 6a includes a heating roller (heating member) 61 and a pressure roller (pressure member) 62. The heating roller 61 and the pressure roller 62 are pressure-contacted to form a nip portion N, and the toner image is heated and pressurized by passing the paper through the nip portion N to be melt-fixed on the paper P. The configuration of the fixing device 6a for recovering UFP will be described later.

The paper P on which the toner image is fixed on the front surface by the fixing device 6a is discharged as it is during single-sided printing, and is again conveyed to the secondary transfer unit 15 via the reverse transfer path during double-sided printing. After the image is formed on the surface, the paper is discharged.

Further, the image forming apparatus 1 has a control unit 20. The control unit 20 includes a storage unit including a CPU (Central Processing Unit) and a ROM, RAM, and HDD, and the CPU executes a program stored in the storage unit to execute an image forming unit 2 and an automatic document transport unit. 3. Control of the document reading unit 4 and the paper feeding unit 5, on / off control of the cooling fan F1 described later, opening / closing operation of the first shutter member 71 and the second shutter member 76, and on / off control of the exhaust fan F2. can.

(Fixing device)
FIG. 2 shows a vertical cross-sectional view of the fixing device 6a. Further, FIG. 3 shows a cross-sectional view of the fixing device 6a as seen from the direction of arrow A in FIG. The fixing device 6a includes a heating roller 61 that is long in the paper passing width direction (front-back direction in FIG. 3) orthogonal to the conveying direction of the paper P, a pressure roller 62 that extends parallel to the heating roller 61 and faces the heating roller 61, and a heating roller 61. And a housing 60 that covers the pressure roller 62. The heating roller 61 and the pressure roller 62 are pressure-welded with an urging member (not shown) to form a nip portion N.

The heating roller 61 is arranged on the unfixed image forming surface side of the paper P, and is rotated clockwise in FIG. 2 by a drive source such as a motor (not shown). The heating roller 61 has a configuration in which, for example, an elastic layer made of silicone rubber or the like is formed on the outer peripheral surface of a columnar core metal made of iron or the like, and a release layer such as fluororesin is further formed on the outer periphery thereof. However, a halogen heater H as a heat source is built in the central hollow portion of the core metal so as to extend in the width direction of the paper. The heating roller 61 comes into contact with the image forming surface of the paper P on which the toner image is transferred, and heats the paper P at a predetermined fixing temperature. The fixing temperature is a temperature at which the amount of heat required to melt the toner can be supplied when the paper P passes through the nip portion N, and varies depending on the paper type of the paper P on which the image is formed. Further, the heat source for heating the heating roller 61 is not limited to the halogen heater, and a conventionally known heat source such as an IH heater or a resistance heating element can be used.

On the other hand, the pressurizing roller 62 is arranged to face the heating roller 61 and is pressed against the heating roller 61 with a predetermined pressing force. That is, the pressure roller 62, together with the heating roller 61, functions as a pressure unit that sandwiches and pressurizes the paper P. The pressure roller 62 has, for example, a configuration in which an elastic layer made of silicone rubber or the like is formed on the outer peripheral surface of a cylindrical core metal made of iron or the like, and a release layer such as fluororesin is further formed on the outer periphery thereof. Have. Further, by making the surface of the pressure roller 62 relatively hard with respect to the surface of the heating roller 61, the pressure roller 62 is pressed against the heating roller 61 and is applied to the elastic layer on the surface of the heating roller 61. A nip portion N having a shape that bites into the nip portion N is formed. Further, a temperature sensor (temperature detection member) S for detecting the surface temperature of the heating roller 61 is provided in the vicinity of the outer periphery of the pressurizing roller 62. The control unit 20 controls on / off of the cooling fan F1, which will be described later, based on the temperature detected by the temperature sensor S.

The housing 60 has an upper housing 60a that covers the heating roller 61 and a lower housing 60b that covers the pressure roller 62. An inlet portion 601 and an outlet portion 602 extending in the paper passing width direction are formed at a substantially central portion in the height direction of the left and right side surfaces of the housing 60, that is, a boundary portion between the upper housing 60a and the lower housing 60b. The paper P is carried into the fixing device 6a from the inlet portion 601 and carried out from the outlet portion 602.

A first intake port 63 is formed at a position facing the longitudinal direction of the heating roller 61 of the upper housing 60a, more specifically, substantially in the center of the upper surface of the upper housing 60a in the front-rear direction, and the first exhaust passage 64 is connected to the upper housing 60a. The first exhaust passage 64 is provided so as to project outward from the upper surface of the upper housing 60a, and an exhaust fan (exhaust means) F2 is provided in the middle of the first exhaust passage 64.

Further, as shown in FIG. 3, second intake ports 65a and 65b are formed at positions facing both ends in the longitudinal direction of the heating rollers 61 on both front and rear surfaces of the housing 60, and the second exhaust passages 66a and 66b are connected to each other. ing. The second exhaust passages 66a and 66b extend along the front and rear side surfaces and the upper surface of the upper housing 60a and join the first exhaust passage 64 while using the front and rear side surfaces and the upper surface of the upper housing 60a as a part of the exhaust passage. .. When the first exhaust passage 64 and the second exhaust passages 66a and 66b merge, the air in these exhaust passages is discharged to the outside from the apparatus main body by the common exhaust fan F2. The first exhaust passage 64 and the second exhaust passages 66a and 66b may be connected to the exhaust fan F2 without merging with each other.

A first shutter member 71 that closes and opens the first intake port 63 is provided on the upper inner side surface of the upper housing 60a. FIG. 4 shows a perspective view showing the first shutter member 71 and its moving mechanism. Note that FIG. 4 is drawn with the vertical direction reversed so that the moving mechanism and the like can be easily understood. The first shutter member 71 has a thin plate shape extending in the front-rear direction, and has an opening 72 having the same shape as the first intake port 63 or having a shape including the first intake port 63 in the opening region when superposed. Have. One end of the first shutter member 71 is connected to one end of the lever 74 that swings around the support shaft 741. The other end of the lever 74 is connected to the tip of the plunger 732 of the solenoid 73. The plunger 732 is provided so as to be accessible to and from the solenoid main body 731, and a compression coil spring 75 is mounted on the outer periphery of the plunger 732.

When the energization to the solenoid 73 is off, the plunger 732 maintains a state of protruding from the solenoid main body 731 by the urging force of the compression coil spring 75. At this time, the opening 72 of the first shutter member 71 and the first intake port 63 are in an overlapping state, that is, the first intake port 63 is in an open state. On the other hand, when the solenoid 73 is energized, the plunger 732 is pulled into the solenoid 73 main body 731 against the urging force of the compression coil spring 75. As a result, the lever 74 swings around the support shaft 741, and the first shutter member 71 moves to a position where the opening 72 does not overlap with the first intake port 63. That is, the first intake port 63 is closed by the first shutter member 71. The moving mechanism of the first shutter member 71 may use a drive source such as a motor.

Further, as shown in FIG. 3, two cooling fans (cooling means) F1 are provided on the bottom surface of the lower housing 60b at a predetermined distance in the front-rear direction. Air is sent toward the heating roller 61 by these cooling fans F1, and the pressure roller 62 is air-cooled. The number of cooling fans F1 to be attached is not particularly limited and may be one or three or more. Further, the mounting position of the cooling fan F1 is preferably a position where the pressure roller 62 can be effectively cooled and the heating roller 61 is not cooled. Usually, the mounting position of the cooling fan F1 is preferably on the pressure roller 62 side of the nip portion N, and more preferably on the opposite side of the heating roller 61 across the pressure roller 62.

(When the pressure roller 62 is cooled)
The control unit 20 determines that the pressure roller 62 is cooled when the detection temperature of the temperature sensor S exceeds a predetermined temperature. Then, as shown in FIG. 4B, the control unit 20 energizes the solenoid 73 and pulls the plunger 732 into the solenoid 73 main body 731 against the urging force of the compression coil spring 75 to push the first shutter member 71. The first intake port 63 is closed as a closed position. At the same time, as shown in FIGS. 5 and 6, the control unit 20 rotationally drives the cooling fan F1 and blows air onto the pressurizing roller 62 to cool the air. The exhaust fan F2 rotates while the halogen heater H as a heating source is energized and controlled, in other words, the heating roller 61 is temperature controlled (fixing process mode, standby mode, sleep mode, etc.). Driven.

The air sent out from the cooling fan F1 hits the pressurizing roller 62 to air-cool the pressurizing roller 62, and most of them are from the second intake ports 65a and 65b formed at positions facing both ends in the longitudinal direction of the heating roller 61. 2 It is sucked into the exhaust passages 66a and 66b. On the other hand, although some air flows into the upper housing 60a, it stays in the upper housing 60a because the first intake port 63 is blocked, and the subsequent air is less likely to flow into the upper housing 60a. As a result, the heating roller 61 is less susceptible to the cooling action of air from the cooling fan F1. The UFP generated from the heating roller 61 and the pressurizing roller 62 includes the second intake ports 65a and 65b, the second exhaust passages 66a and 66b, and the first exhaust from the inside of the housing 60 together with the air flow generated by the cooling fan F1 and the exhaust fan F2. It passes through the road 64 and is supplemented by a filter (not shown) provided in the middle of the first exhaust passage 64. Then, the air from which the UFP has been removed is discharged to the outside from the main body of the apparatus.

(Normal and warm-up)
The control unit 20 determines that cooling of the pressurizing roller 62 is unnecessary when the detection temperature of the temperature sensor S is normally equal to or lower than a predetermined temperature and when the heating roller 61 is warmed up to a target temperature. As shown in FIG. 4A, the control unit 20 stops energizing the solenoid 73. As a result, the plunger 732 protrudes from the solenoid main body 731 by the urging force of the compression coil spring 75, the first shutter member 71 is in the open position, and the first intake port 63 is in the open state. At the same time, as shown in FIGS. 7 and 8, the control unit 20 stops the rotational drive of the cooling fan F1 to stop blowing air onto the pressurizing roller 62. On the other hand, the control unit 20 continues the rotary drive of the exhaust fan F2. As a result, the pressurizing roller 62 and the heating roller 61 are not air-cooled by the cooling fan F1. Further, the UFP generated from the heating roller 61 and the pressurizing roller 62 is sucked not only from the second intake ports 65a and 65b but also from the first intake port 63 together with the air in the housing 60, and is sucked from the first exhaust passage 64 and the second exhaust. It passes through the passages 66a and 66b and is supplemented by a filter (not shown) provided in the middle of the first exhaust passage 64. Then, the air from which the UFP has been removed is discharged to the outside from the main body of the device. Since the amount of UFP generated increases during warm-up, the control unit 20 may control the amount of exhaust gas generated by the exhaust fan F2 during warm-up to be larger than during normal operation.

(Second Embodiment)
Next, the fixing device 6b according to the second embodiment of the present invention will be described with reference to FIGS. 9 to 11. FIG. 9 shows a vertical cross-sectional view of the fixing device 6b. Further, FIG. 10 shows a side view of the fixing device 6b as seen from the arrow A in FIG. Since the basic configuration of this embodiment is the same as that of the first embodiment described above, the components common to the first embodiment are given the same names and the same reference numerals as before, and the details thereof are given. The explanation may be omitted.

In the fixing device 6b of the second embodiment, as shown in FIG. 9, the first intake port 63 is located at a position facing the longitudinal direction of the pressure roller 62 of the lower housing 60b, more specifically, of the lower housing 60b. It is formed substantially in the center of the right side surface in the front-rear direction, and the first exhaust passage 64 is connected there. The first exhaust passage 64 is provided so as to project outward from the right side surface of the lower housing 60b, and an exhaust fan F2 is provided in the middle of the first exhaust passage 64.

Further, as shown in FIG. 10, second intake ports 65a and 65b are formed at positions facing both ends in the longitudinal direction of the heating rollers 61 on both front and rear surfaces of the housing 60, as in the first embodiment. The second exhaust passages 66a and 66b are connected there. The second exhaust passages 66a and 66b extend the front and rear side surfaces of the lower housing 60b in the lower right direction while using the front and rear side surfaces and the right side surface of the lower housing 60b as a part of the second exhaust passages 66a and 66b, and the right side surface. Extends horizontally from both front and rear sides toward the center in the front-rear direction and joins the first exhaust passage 64. Similar to the first embodiment, when the first exhaust passage 64 and the second exhaust passages 66a and 66b merge, the air in these exhaust passages is discharged to the outside from the apparatus main body by the common exhaust fan F2. The first exhaust passage 64 and the second exhaust passages 66a and 66b may be connected to the exhaust fan F2 without merging with each other.

Further, two cooling fans F1 are provided at a corner on the bottom surface of the lower housing 60b opposite to the first intake port 63 at a predetermined distance in the front-rear direction so as to generate an air flow toward the pressurizing roller 62. ing. Air is sent toward the heating roller 61 by these cooling fans F1, and the pressure roller 62 is air-cooled. The number of cooling fans F1 to be attached is not particularly limited and may be one or three or more. Further, the mounting position of the cooling fan F1 is preferably a position where the pressurizing roller 62 can be effectively cooled and the heating roller 61 is not cooled, but the air flow generated by the cooling fan F1 is sent to the first intake port 63. From the viewpoint of smooth inflow, the mounting position of the cooling fan F1 shown in FIGS. 9 and 10 is preferable.

Second shutter members 76a and 76b are provided at the lower edges of the inlet portion 601 and the outlet portion 602 of the housing 60. The second shutter members 76a and 76b have a plate shape extending in the front-rear direction, and the length in the front-rear direction is slightly shorter than the length in the front-rear direction of the pressure roller 62. As a result, as will be described later, when the second shutter members 76a and 76b are in the closed position, the pressure roller 62 is not blocked by the second shutter members 76a and 76b at both ends in the axial direction and is inside the lower housing 60b. An opening is formed so that the air of the above can flow into the second intake ports 65a and 65b.

The second shutter members 76a and 76b are attached to the lower edges of the inlet portion 601 and the outlet portion 602 of the housing 60 on one end side in the lateral direction, and the open position and pressurization with the other end side in the lateral direction facing downward. It can swing to a closed position facing the direction of the roller 62. FIG. 11 shows a perspective view showing the second shutter members 76a and 76b and their swinging mechanism. The second shutter members 76a and 76b and their swinging mechanism are symmetrically provided around the pressure roller 72, and the swinging mechanism for opening and closing the second shutter members 76a and 76b is the same mechanism. Hereinafter, the swing mechanism of the second shutter member 76a will be described as an example.

The second shutter member 76a has a thin plate shape extending in the front-rear direction, and has a contact piece 762 attached to a swing shaft 761 protruding outward from an end portion in the front-rear direction. A solenoid 73, a lever 77, and a rod-shaped member 78 are attached to a frame 79 provided in the housing 60. One end of the lever 77 is rotatably supported by a support shaft 771 on the frame 79, and the other end of the lever 77 is connected to the upper end of a rod-shaped member 78 arranged in the vertical direction. The tip of the plunger 732 of the solenoid 73 is connected to the middle of the lever 77. The plunger 732 is provided so as to be accessible to and from the solenoid 73 main body 731, and a compression coil spring 75 is mounted on the outer periphery of the plunger 732. An urging member (for example, a torsion spring) (not shown) is attached between the abutting piece 762 of the second shutter member 76a and the frame 79, and the abutting piece 762 is always urged in the direction of the rod-shaped member 78. It is in contact with the lower end of the rod-shaped member 78.

When the energization to the solenoid 73 is off, the plunger 732 projects from the solenoid body 731 by the urging force of the compression coil spring 75 and maintains a state in which the lever 77 is rotated upward. As a result, the rod-shaped member 78 is pulled upward by the lever 77, and the second shutter member 76a rotates until the contact piece 762 abuts on the lower end of the rod-shaped member 78. That is, the second shutter member 76a is in a horizontal state, and is in a closed position that prevents the air generated by the cooling fan F1 from heading toward the heating roller 61.

On the other hand, when the solenoid 73 is energized, the plunger 732 is pulled into the solenoid body 731 against the urging force of the compression coil spring 75. As a result, the lever 77 rotates downward about the support shaft 771, and the rod-shaped member 78 is pushed downward. Then, the contact piece 762 is rotated downward by the rod-shaped member 78, the second shutter member 76a is in a vertical state, and the open position that allows the air generated by the cooling fan F1 to go toward the heating roller 61. It becomes. As in the first embodiment, the moving mechanism of the second shutter member 76a may use a drive source such as a motor.

(When the pressure roller 62 is cooled)
The control unit 20 determines that the pressure roller 62 is cooled when the detection temperature of the temperature sensor S exceeds a predetermined temperature. Then, as shown in FIG. 11A, the control unit 20 turns off the energization of the solenoid 73. As a result, the plunger 732 is in a state of protruding from the solenoid main body 731 by the urging force of the compression coil spring 75, the lever 77 is rotated upward, and the rod-shaped member 78 is in a state of being pulled up upward, and the second shutter member 76a, 76b is in the closed position. At the same time, as shown in FIGS. 12 and 13, the control unit 20 rotationally drives the cooling fan F1 and blows air onto the pressurizing roller 62 to cool the air. As in the first embodiment, the exhaust fan F2 is rotationally driven while the halogen heater H as a heating source is energized and controlled.

The air sent out from the cooling fan F1 hits the pressurizing roller 62 to air-cool the pressurizing roller 62, and the first intake port 63 and the heating roller 61 formed at substantially the center of the right side surface of the lower housing 60b in the front-rear direction. The second intake ports 65a and 65b formed at positions facing both ends are sucked into the first exhaust passage 64 and the second exhaust passages 66a and 66b. On the other hand, since most of the air generated by the cooling fan F1 is prevented from going toward the heating roller 61 by the second shutter members 76a and 76b, the heating roller 61 is less likely to be cooled by the air from the cooling fan F1. Become. The UFP generated from the heating roller 61 and the pressurizing roller 62 includes the first intake port 63, the second intake ports 65a, 65b, and the first exhaust passage 64 from the inside of the housing 60 together with the air flow generated by the cooling fan F1 and the exhaust fan F2. And through the second exhaust passages 66a and 66b, it is supplemented by a filter (not shown) provided in the middle of the first exhaust passage 64. Then, the air from which the UFP has been removed is discharged to the outside from the main body of the apparatus.

(Normal and warm-up)
The control unit 20 determines that cooling of the pressurizing roller 62 is unnecessary when the detection temperature of the temperature sensor S is normally equal to or lower than a predetermined temperature and when the heating roller 61 is warmed up to a target temperature. As shown in FIG. 11B, the control unit 20 energizes the solenoid 73. As a result, the plunger 732 is pulled into the solenoid body 731 against the urging force of the compression coil spring 75, the lever 77 is rotated downward, and the rod-shaped member 78 is pushed downward. 2 The shutter members 76a and 76b are in the open position. At the same time, as shown in FIGS. 14 and 15, the control unit 20 stops the rotational drive of the cooling fan F1 to stop blowing air onto the pressurizing roller 62. On the other hand, the control unit 20 continues the rotary drive of the exhaust fan F2. As a result, the pressurizing roller 62 and the heating roller 61 are not air-cooled by the cooling fan F1. Further, the UFP generated from the heating roller 61 and the pressurizing roller 62 is sucked from the first intake port 63 and the second intake ports 65a and 65b together with the air in the housing 60, and is sucked from the first exhaust passage 64 and the second exhaust passage 66a, Through 66b, it is supplemented by a filter (not shown) provided in the middle of the first exhaust passage 64. Then, the air from which the UFP has been removed is discharged to the outside from the main body of the device. Since the amount of UFP generated increases during warm-up, the control unit may control the exhaust amount by the exhaust fan F2 during warm-up to be larger than that during normal operation, as in the first embodiment. ..

(Other embodiments)
In all of the embodiments described above, the paper is conveyed horizontally to the fixing device, but the fixing device of the present invention can also be applied to a form in which the paper is conveyed vertically. In this case, the horizontal direction and the vertical direction of the drawings showing the respective embodiments may be applied as the vertical direction and the horizontal direction, respectively.

The heating member and the pressurizing member in the present invention are not limited to the roller shape, and may be, for example, a belt shape.

When the pressurizing member needs to be cooled, the fixing device according to the present invention can cool the pressurizing member without lowering the temperature of the heating member as much as possible, and the amount of UFP generated at the time of warming up is increased. In the case of a large amount, UFP can be efficiently recovered, which is useful.

1 Image forming device 6a, 6b Fixing device F1 Cooling fan (cooling means)
F2 exhaust fan (exhaust means)
H halogen heater (heat source)
P Paper S Temperature sensor (Temperature detection member)
20 Control unit 60 Housing 60a Upper housing 60b Lower housing 61 Heating roller (heating member)
62 Pressurized roller (pressurized member)
63 First intake port 64 First exhaust passage 65a, 65b Second intake port 66a, 66b Second exhaust passage 71 First shutter member 76a, 76b Second shutter member

Claims (6)

A recording material having a heating member heated by a heating source and a pressurizing member that presses against the heating member and having a toner image formed in a nip portion between the heating member and the pressurizing member is passed through the toner image. In the fixing device that fixes the
A cooling means that causes the flow of air toward the pressurizing member and cools the pressurizing member.
A first exhaust passage having a first intake port at a predetermined position facing the heating member or the pressurizing member in the longitudinal direction,
A second exhaust passage having a second intake port in the vicinity of both ends in the longitudinal direction of the heating member,
Exhaust means for discharging the air flowing in from the first intake port and the second intake port to the outside from the main body of the apparatus through the first exhaust passage and the second exhaust passage.
A cooling suppressing means for suppressing the air generated by the cooling means from cooling the heating member, and a cooling suppressing means.
A control unit that operates the cooling suppressing means during the operation of the cooling means is provided.
The cooling suppressing means is a first shutter member that can move between a closed position that closes the first intake port and an open position that opens the first intake port.
The control unit sets the first shutter member in the closed position during the operation of the cooling means.
The cooling means is located on the pressure member side when viewed from the nip portion.
A fixing device characterized in that the first intake port is located on the heating member side when viewed from the nip portion. A recording material having a heating member heated by a heating source and a pressurizing member that presses against the heating member and having a toner image formed in a nip portion between the heating member and the pressurizing member is passed through the toner image. In the fixing device that fixes the
A cooling means that causes the flow of air toward the pressurizing member and cools the pressurizing member.
A first exhaust passage having a first intake port at a predetermined position facing the heating member or the pressurizing member in the longitudinal direction,
A second exhaust passage having a second intake port in the vicinity of both ends in the longitudinal direction of the heating member,
Exhaust means for discharging the air flowing in from the first intake port and the second intake port to the outside from the main body of the apparatus through the first exhaust passage and the second exhaust passage.
A cooling suppressing means for suppressing the air generated by the cooling means from cooling the heating member, and a cooling suppressing means.
A control unit that operates the cooling suppressing means during the operation of the cooling means is provided.
The cooling suppressing means is a second shutter member that can move to a closed position that prevents the air generated by the cooling means from heading toward the heating member and an acceptable open position.
The control unit sets the second shutter member in the closed position during the operation of the cooling means.
The second shutter member is a plate-shaped member that is long in the longitudinal direction of the pressurizing member, is located in the vicinity of the pressurizing member, and swings around an axis substantially parallel to the longitudinal direction of the pressurizing member. , Preventing or tolerating the air generated by the cooling means towards the heating member,
A fixing device characterized in that the cooling means and the first intake port are located on the side opposite to the nip portion when viewed from the installation position of the second shutter member. A temperature detecting member for detecting the temperature of the pressure member is further provided.
The fixing device according to claim 1 or 2 , wherein the control unit operates the cooling means when the temperature measured by the temperature detecting member becomes equal to or higher than a predetermined temperature. The fixing device according to any one of claims 1 to 3 , wherein the control unit does not operate the cooling suppressing means at the time of warming up. The fixing device according to any one of claims 1 to 4 , wherein the control unit increases the amount of exhaust gas by the exhaust means at the time of warm-up as compared with the case of normal operation. An image forming apparatus comprising the fixing apparatus according to any one of claims 1 to 5.

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