JP2018097049A - Fixation device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixation device which can increase the UFP recovery amount when the UFP generation amount is large at the time of warm-up or the like without reducing the temperature of a heat roller as much as possible at the time of cooling a pressure roller.SOLUTION: A fixation device includes: a cooling fan F1 which cools a pressure roller 62; a first exhaust path 64 which has a first suction port 63 at a prescribed position facing the longitudinal direction of a heat roller 61 or pressure roller 62; second exhaust paths 66a, 66b which have second suction ports 65a, 65b in the vicinity of both ends in the longitudinal direction of the heat roller 61; an exhaust fan F2 which discharges the air flown in from the first suction port 63 and second suction ports 65a, 65b to the outside from the device body through the first exhaust path 64 and second exhaust paths 66a, 66b; a first shutter member 71 which is movable to the close position of closing the first suction port 63 and the open position of opening the first suction port; and a control unit which makes the first shutter member 71 located at the close position during the operation of the cooling fan F1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a fixing device and an image forming apparatus having the same.

  Conventionally, in an image forming apparatus adopting an electrophotographic method, a sheet 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 pressed against the heating roller. It is widely performed to melt and fix an unfixed toner image on a sheet by pressing.

  In the fixing device of this type, the pressure roller may become high temperature due to the heating movement from the heating roller. When image formation on both sides of a sheet is performed, if the fixed toner image on the first surface comes into contact with a high-temperature pressure roller when the unfixed toner image on the second surface is fixed, image noise such as a gloss level difference occurs on the fixed toner image on the first surface. There is a problem that image quality is deteriorated.

  In order to prevent this image noise, various fixing devices including a cooling unit that cools with a wind of a fan when a pressure roller reaches a predetermined temperature or more have been proposed. For example, Patent Document 1 proposes a fixing device that cools a pressure member with wind of a cooling fan.

  On the other hand, it is known that silicon rubber and toner used in a heating roller and a fixing belt emit UFP (Ultra Fine Particles) by heat during fixing. Therefore, there is a technique in which air in the fixing device is sucked with a fan so that UFP is not released outside the device, and after the UFP is removed by a filter, the air is discharged outside the device. For example, Patent Document 2 proposes to control the operation of a recovery fan so that UFP can be recovered in an initial burst condition where a large amount of UFP is generated.

  However, in the method in which the air in the fixing device is sucked by the fan in order to collect the UFP, the temperature of the heating roller may be lowered by the air flow generated by the fan. Therefore, in Patent Document 3, in order to prevent the temperature of the heating roller and the pressure roller from decreasing, it has been proposed to generate a UFP recovery air flow only at the end of the roller where a large amount of UFP is released.

JP 2010-204551 A JP 2011-180341 A JP 2010-134133 A

  However, coexistence of cooling the pressure roller in order to prevent image noise such as a gloss level difference, generating an air flow to recover UFP generated from the fixing member, and suppressing a decrease in temperature of the heating roller. I haven't done enough yet.

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

  The fixing device according to the present invention that achieves the above object includes a heating member that is heated by a heating source, and a pressure member that is in pressure contact with the heating member, and a toner in a nip portion between the heating member and the pressure member. A fixing device for passing a recording material on which an image is formed and fixing a toner image on the recording material, wherein a cooling means for cooling the pressure member by causing an air flow toward the pressure 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 pressure member, and a second exhaust passage having a second intake port in the vicinity of both longitudinal ends of the heating member; Exhaust means for exhausting air flowing in from the first intake port and the second intake port from the apparatus main body through the first exhaust passage and the second exhaust passage, and air generated by the cooling means causes the heating member to Cooling suppression means for suppressing cooling and Wherein during operation of the cooling means, characterized in that it comprises a control unit for operating the cooling suppression means.

  In the fixing device having the above-described configuration, the cooling suppression unit is a first shutter member that can be moved between a closed position for blocking the first intake port and an open position for opening the first intake port. It is good also as a structure which makes 1 shutter member a closed position. At this time, the cooling means may be positioned on the pressure member side when viewed from the nip portion, and the first intake port may be positioned on the heating member side when viewed from the nip portion.

  Further, in the fixing device having the above-described configuration, the cooling suppression unit is a second shutter member that is movable between a closed position that prevents the air generated by the cooling unit from moving toward the heating member and an open position that is acceptable. The said control part is good also as a structure which makes a 2nd shutter member a closed position during the action | operation of the said cooling means. At this time, the second shutter member is a plate-like member that is long in the longitudinal direction of the pressure member and is located in the vicinity of the pressure member, and swings about an axis that is substantially parallel to the longitudinal direction of the pressure member. The cooling means and the air generated by the cooling means are blocked or allowed to go to the heating member, and the cooling means and the first air inlet are opposite to the nip portion when viewed from the installation position of the second shutter member. It is good also as a structure located in the side.

  Further, in the fixing device having the above-described configuration, a temperature detection member that detects the temperature of the pressure member is further provided, and the control unit activates the cooling unit when the temperature measured by the temperature detection member is equal to or higher than a predetermined temperature. It is good also as a structure.

  Further, in the fixing device having the above-described configuration, the control unit may be configured to open the first shutter member or the second shutter member while the cooling unit is not operating.

  In the fixing device having the above-described configuration, the control unit may be configured to deactivate the cooling suppression unit during warm-up. In this specification, “warm-up” refers to raising the temperature of the heating member to a target temperature.

  Further, in the fixing device having the above-described configuration, the control unit may increase the amount of exhaust by the exhaust unit during warm-up than during normal operation.

  According to the present invention, there is provided an image forming apparatus comprising the fixing device as described above.

  According to the fixing device of the present invention, when the pressure member needs to be cooled, the pressure member can be cooled without reducing the temperature of the heating member as much as possible. When there is a large amount, UFP can be recovered efficiently.

1 is a schematic configuration diagram showing an internal configuration of an image forming apparatus of the present invention. FIG. 2 is a vertical sectional view illustrating a configuration of a fixing device in the image forming apparatus according to the first exemplary embodiment of the present invention. FIG. 3 is a cross-sectional view of the fixing device 6a viewed from the direction of an arrow A in FIG. It is a perspective view which shows the 1st shutter member 71 and its moving mechanism. FIG. 6 is a vertical sectional view of the fixing device 6a when the pressure roller 62 is cooled. FIG. 6 is a cross-sectional view of the fixing device 6a as viewed from the direction of arrow A in FIG. 5. FIG. 6 is a vertical sectional view of the fixing device 6a during normal time and during warm-up. It is sectional drawing of the fixing device 6a seen from the direction of the arrow A of FIG. FIG. 6 is a vertical sectional view showing a configuration of a fixing device 6b according to a second embodiment of the present invention. FIG. 10 is a cross-sectional view of the fixing device 6b as seen from the direction of arrow A in FIG. 9. It is a perspective view which shows the 2nd shutter member 76a and its rocking | fluctuation mechanism. FIG. 6 is a vertical sectional view of the fixing device 6b when the pressure roller 62 is cooled. It is sectional drawing of the fixing device 6b seen from the direction of the arrow A of FIG. FIG. 6 is a vertical sectional view of the fixing device 6b during normal time and during warm-up. It is sectional drawing of the fixing device 6b seen from the direction of the arrow A of FIG.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. However, 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 an image forming apparatus according to the present invention. Note that the vertical direction, the horizontal direction, and the paper depth direction in FIG. 1 are the vertical direction, the horizontal direction, and the front-back direction of the image forming apparatus.

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

  The image forming apparatus 1 mainly includes 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 formation based on print settings. The print setting refers to a collection of setting values corresponding to a plurality of setting items related to image formation.

  The automatic document conveying unit 3 automatically conveys the document placed on the document table to the reading position of the document reading unit 4.

  The document reading unit 4 reads an image of the document conveyed by the automatic document conveyance unit 3 and generates read data.

  The sheet feeding unit 5 includes a plurality of sheet feeding trays 51 a to 51 c and supplies sheets as recording materials stored in the sheet feeding trays 51 a to 51 c to the image forming unit 2.

  The image forming unit 2 forms an image on a sheet supplied by the sheet feeding unit 5 based on read data generated by the document reading unit 4 or print data acquired by a 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 sometimes referred to as Y color to K color). A photosensitive member 81, a charging unit 82, an image exposure unit 83, a developing unit 10, a primary transfer unit 11, and a cleaning unit 12. The image forming unit 2 includes an intermediate transfer body 13, a registration roller pair 14, a secondary transfer unit 15, and a fixing device 6a, which are common to Y to K colors.

  Hereinafter, the photoreceptor 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 photoreceptor 81 by irradiating 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 primarily transfers the toner image developed on the photoreceptor 81 to the intermediate transfer member 13. The cleaning unit 12 removes toner remaining on the photoconductor 81 without being transferred to the intermediate transfer body 13 from the photoconductor 81.

  For the M-color to K-color photoconductor 81, charging unit 82, image exposure unit 83, developing unit 10, primary transfer unit 11, and cleaning unit 12, the timing is also set so that the toner images of the corresponding pixels overlap. In addition, the same operation as that of the above-described Y color is performed, and Y to K toner images are formed on the intermediate transfer member 13.

  The registration roller pair 14 corrects the skew of the paper supplied from the paper supply unit 5 and adjusts the timing so that the toner image transferred onto the intermediate transfer member 13 is positioned at a predetermined position on the paper. 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 onto the paper. The fixing device 6 a includes a heating roller (heating member) 61 and a pressure roller (pressure member) 62. The heating roller 61 and the pressure roller 62 are pressed against each other to form a nip portion N. By passing the paper through the nip portion N, the toner image is heated and pressurized and melted and fixed on the paper P. The configuration of the fixing device 6a for collecting UFP will be described later.

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

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

(Fixing device)
FIG. 2 shows a vertical sectional view of the fixing device 6a. FIG. 3 is a cross-sectional view of the fixing device 6a viewed from the direction of the arrow A in FIG. The fixing device 6a includes a heating roller 61 that is long in the sheet passing width direction (the front-rear direction in FIG. 3) orthogonal to the conveyance direction of the sheet P, a pressure roller 62 that extends parallel to 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 pressed against each other by a biasing member (not shown) to form a nip portion N.

  The heating roller 61 is disposed on the unfixed image forming surface side of the paper P and is rotated clockwise in FIG. 2 by a driving 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 cylindrical metal core made of iron or the like, and a release layer such as a fluororesin is formed on the outer periphery thereof. In addition, a halogen heater H as a heat source is incorporated in the central hollow portion of the cored bar so as to extend in the sheet passing width direction. The heating roller 61 comes into contact with the image forming surface of the paper P to which the toner image has been 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 when the paper P passes through the nip portion N, and varies depending on the paper type of the paper P on which an image is formed. The heat source for heating the heating roller 61 is not limited to a 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 pressure roller 62 is disposed 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 functions as a pressure unit that sandwiches and presses the paper P together with the heating roller 61. The pressure roller 62 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 cylindrical metal core made of iron or the like, and a release layer such as a fluororesin is formed on the outer periphery thereof. Have. Further, since the surface of the pressure roller 62 is made relatively hard with respect to the surface of the heating roller 61, the pressure roller 62 is pressed against the heating roller 61 in an elastic layer on the surface of the heating roller 61. A nip portion N having a biting shape is formed. Further, in the vicinity of the outer periphery of the pressure roller 62, a temperature sensor (temperature detection member) S for detecting the surface temperature of the heating roller 61 is provided. Based on the temperature detected by the temperature sensor S, the control unit 20 performs on / off control of a cooling fan F1 described later.

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

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

  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 roller 61 on both front and rear sides of the housing 60, and second exhaust passages 66a and 66b are connected. 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 while joining 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 path 64 and the second exhaust paths 66a and 66b merge, the air in these exhaust paths is exhausted from the apparatus main body by the common exhaust fan F2. The first exhaust path 64 and the second exhaust paths 66a and 66b may be connected to the exhaust fan F2 without joining.

  A first shutter member 71 that seals and opens the first air inlet 63 is provided on the upper inner surface of the upper housing 60a. FIG. 4 is a perspective view showing the first shutter member 71 and its moving mechanism. FIG. 4 is drawn upside down 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 a shape including the first intake port 63 in the opening region when overlapped. Have. One end of the first shutter member 71 is connected to one end of a lever 74 that swings about a 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 able to enter and exit the solenoid body 731, and a compression coil spring 75 is attached to 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 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 overlap each other, that is, the first intake port 63 is open. On the other hand, when the solenoid 73 is energized, the plunger 732 is drawn into the solenoid 73 main body 731 against the urging force of the compression coil spring 75. As a result, the lever 74 swings about the support shaft 741 and the first shutter member 71 moves to a position where the opening 72 does not overlap the first intake port 63. That is, the first intake port 63 is sealed by the first shutter member 71. The moving mechanism of the first shutter member 71 may use a driving source such as a motor.

  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. 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 with respect to 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 temperature detected by the temperature sensor S exceeds a predetermined temperature. 4B, the control unit 20 energizes the solenoid 73 to pull the plunger 732 into the solenoid 73 main body 731 against the urging force of the compression coil spring 75, and the first shutter member 71 is moved. The first intake port 63 is closed as the closed position. At the same time, as shown in FIGS. 5 and 6, the control unit 20 drives the cooling fan F <b> 1 to rotate and blows air to the pressure roller 62 to cool the air. Note that the exhaust fan F2 rotates while the halogen heater H as a heating source is energized, in other words, when the heating roller 61 is temperature controlled (fixing processing mode, standby mode, sleep mode, etc.). Driven.

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

(Normal and warm-up)
The control unit 20 determines that the pressure roller 62 does not need to be cooled when the temperature detected by the temperature sensor S is normal below a predetermined temperature and when the temperature of the heating roller 61 is raised to the target temperature. As illustrated in FIG. 4A, the control unit 20 stops energization of the solenoid 73. As a result, the plunger 732 protrudes from the solenoid 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 rotation of the cooling fan F <b> 1 and stops blowing air to the pressure roller 62. On the other hand, the control unit 20 continues to drive the exhaust fan F2. Thereby, the pressure roller 62 and the heating roller 61 are not air-cooled by the cooling fan F1. Further, UFP generated from the heating roller 61 and the pressure roller 62 is sucked not only from the second intake ports 65 a and 65 b but also from the first intake port 63 together with the air in the housing 60, and the first exhaust path 64 and the second exhaust path. The passage is supplemented by a filter (not shown) provided in the middle of the first exhaust passage 64 through the passages 66a and 66b. The air from which the UFP has been removed is discharged outside from the apparatus main body. Since the amount of UFP generated increases during warm-up, the control unit 20 may control the exhaust amount by the exhaust fan F2 to increase more than during normal operation during warm-up.

(Second Embodiment)
Next, a fixing device 6b according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 9 shows a vertical sectional view of the fixing device 6b. FIG. 10 is a side view of the fixing device 6b as viewed 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 same components as those in the first embodiment are assigned the same names and the same reference numerals as before, and the details thereof are the same. The description may be omitted.

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

  Also, 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 roller 61 on both front and rear sides 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 use 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, while extending the front and rear side surfaces of the lower housing 60b in the lower right direction. Extends horizontally from the front and rear sides toward the center in the front-rear direction and merges with the first exhaust path 64. Similar to the first embodiment, when the first exhaust path 64 and the second exhaust paths 66a and 66b merge, the air in these exhaust paths is exhausted from the apparatus main body by the common exhaust fan F2. The first exhaust path 64 and the second exhaust paths 66a and 66b may be connected to the exhaust fan F2 without joining.

  In addition, two cooling fans F1 are provided at a predetermined distance in the front-rear direction so that an air flow toward the pressure roller 62 is generated at a corner of the bottom surface of the lower housing 60b opposite to the first intake port 63. 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. 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. However, the air flow generated by the cooling fan F1 flows into the first intake port 63. From the viewpoint of smoothly flowing in, the mounting position of the cooling fan F1 shown in FIGS. 9 and 10 is preferable.

  Second shutter members 76 a and 76 b are provided at the lower edge portions of the inlet portion 601 and the outlet portion 602 of the housing 60. The second shutter members 76 a and 76 b 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, they are not sealed by the second shutter members 76a and 76b at the both ends in the axial direction of the pressure roller 62, and the inside of the lower housing 60b. Are formed so that the air can flow into the second intake ports 65a and 65b.

  The second shutter members 76a and 76b are attached to the lower edge portions of the inlet portion 601 and the outlet portion 602 of the housing 60 at one end in the short direction, and are open and pressed with the other end in the short direction facing downward. It can swing to a closed position facing the direction of the roller 62. FIG. 11 is a perspective view showing the second shutter members 76a and 76b and the swing mechanism thereof. The second shutter members 76a and 76b and the swing mechanism thereof are provided symmetrically around the pressure roller 72, and the swing mechanism that opens and closes 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 the front-rear direction end. A solenoid 73, a lever 77, and a rod-shaped member 78 are attached to the frame 79 provided in the housing 60. One end of the lever 77 is rotatably supported on the frame 79 by a support shaft 771, and the other end of the lever 77 is connected to the upper end of a bar-like 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 able to enter and exit the solenoid 73 main body 731, and a compression coil spring 75 is attached to the outer periphery of the plunger 732. A biasing member (not shown) (for example, a torsion spring) is attached between the contact piece 762 of the second shutter member 76a and the frame 79, and the contact piece 762 is always biased 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 of the solenoid 73 is off, the plunger 732 protrudes from the solenoid body 731 by the urging force of the compression coil spring 75 and maintains the state where 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 contacts 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 moving toward the heating roller 61.

  On the other hand, when the solenoid 73 is energized, the plunger 732 is drawn 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 an open position that allows the air generated by the cooling fan F1 to travel toward the heating roller 61 is accepted. It becomes. Note that, similarly to the first embodiment, the moving mechanism of the second shutter member 76a may use a driving 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 temperature detected by the temperature sensor S exceeds a predetermined temperature. And as shown to Fig.11 (a), the control part 20 turns off the electricity supply to the solenoid 73. FIG. As a result, the plunger 732 protrudes from the solenoid body 731 by the urging force of the compression coil spring 75, the lever 77 rotates upward, and the rod-shaped member 78 is pulled upward, so that the second shutter member 76a, 76b is a closed position. At the same time, as shown in FIGS. 12 and 13, the control unit 20 drives the cooling fan F <b> 1 to rotate and blows air to the pressure roller 62 for air cooling. As in the first embodiment, the exhaust fan F2 is rotationally driven while the halogen heater H as a heating source is energized.

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

(Normal and warm-up)
The control unit 20 determines that the pressure roller 62 does not need to be cooled when the temperature detected by the temperature sensor S is normal below a predetermined temperature and when the temperature of the heating roller 61 is raised to the 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 pressed downward. The two 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 rotation drive of the cooling fan F <b> 1 and stops blowing air to the pressure roller 62. On the other hand, the control unit 20 continues to drive the exhaust fan F2. Thereby, the pressure roller 62 and the heating roller 61 are not air-cooled by the cooling fan F1. The UFP generated from the heating roller 61 and the pressure roller 62 is sucked together with the air in the housing 60 from the first intake port 63 and the second intake ports 65a and 65b, and the first exhaust path 64 and the second exhaust path 66a, 66b is supplemented by a filter (not shown) provided in the middle of the first exhaust path 64. The air from which the UFP has been removed is discharged outside from the apparatus main body. Since the amount of UFP generated increases during warm-up, the control unit may control to increase the exhaust amount by the exhaust fan F2 during normal warm-up as in the first embodiment. .

(Other embodiments)
In any of the embodiments described above, the sheet is conveyed in the horizontal direction with respect to the fixing device. However, the fixing apparatus of the present invention can also be applied to a form in which the sheet is conveyed in the vertical direction. In this case, the horizontal direction and the vertical direction in the drawings showing the embodiments may be applied as the vertical direction and the horizontal direction, respectively.

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

  When the pressure member needs to be cooled, the fixing device according to the present invention can cool the pressure member without reducing the temperature of the heating member as much as possible, and the amount of UFP generated during warm-up is reduced. In many cases, UFP can be efficiently recovered, which is useful.

1 Image forming apparatus 6a, 6b Fixing apparatus F1 Cooling fan (cooling means)
F2 Exhaust fan (exhaust means)
H Halogen heater (heating source)
P Paper S Temperature sensor (temperature detection member)
20 Control part 60 Housing 60a Upper housing 60b Lower housing 61 Heating roller (heating member)
62 Pressure roller (Pressure member)
63 1st inlet port 64 1st exhaust path 65a, 65b 2nd inlet port 66a, 66b 2nd exhaust path 71 1st shutter member 76a, 76b 2nd shutter member

Claims (10)

A heating member that is heated by a heating source; and a pressure member that is in pressure contact with the heating member, and a recording material on which a toner image is formed is passed through a nip portion between the heating member and the pressure member. In a fixing device for fixing a recording material to a recording material,
Cooling means for causing air flow toward the pressure member to cool the pressure member;
A first exhaust passage having a first air inlet at a predetermined position facing the longitudinal direction of the heating member or the pressure member;
A second exhaust passage having a second intake port in the vicinity of both longitudinal ends of the heating member;
Exhaust means for exhausting air flowing in from the first intake port and the second intake port from the apparatus main body through the first exhaust passage and the second exhaust passage;
Cooling suppression means for suppressing air generated by the cooling means from cooling the heating member;
And a controller that operates the cooling suppression unit during the operation of the cooling unit. The cooling suppression means is a first shutter member movable between a closed position for blocking the first air inlet and an open position for opening;
The fixing device according to claim 1, wherein the control unit sets the first shutter member to a closed position during operation of the cooling unit. The cooling means is located on the pressure member side when viewed from the nip portion;
The fixing device according to claim 2, wherein the first air inlet is positioned on the heating member side when viewed from the nip portion. The cooling suppression means is a second shutter member that is movable between a closed position that prevents air generated by the cooling means from moving toward the heating member and an open position that is acceptable;
The fixing device according to claim 1, wherein the control unit sets the second shutter member to a closed position during operation of the cooling unit. The second shutter member is a plate-like member that is long in the longitudinal direction of the pressure member and is positioned in the vicinity of the pressure member, and swings about an axis substantially parallel to the longitudinal direction of the pressure member. Preventing or allowing the air generated by the cooling means to travel toward the heating member;
The fixing device according to claim 4, wherein the cooling unit and the first air inlet are located on a side opposite to the nip portion when viewed from a position where the second shutter member is installed. A temperature detection member for detecting the temperature of the pressure member;
The fixing device according to claim 1, wherein the control unit activates the cooling unit when a temperature measured by the temperature detection member is equal to or higher than a predetermined temperature.   The fixing device according to claim 1, wherein the control unit opens the first shutter member or the second shutter member while the cooling unit is not in operation.   The fixing device according to claim 1, wherein the control unit deactivates the cooling suppression unit during warm-up.   The fixing device according to claim 1, wherein the control unit increases the amount of exhaust by the exhaust unit during warm-up than during normal operation.   An image forming apparatus comprising the fixing device according to claim 1.