JP2010139908A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve, at a low cost, a constitution for preventing pressurization by a pressure roller in the state in which a fixing unit is removed from a device body. <P>SOLUTION: This image forming device is equipped with: the fixing unit 14 that has the pressure roller 62 for pressurizing a recording material S and is attachable/detachable from the body 1 of the image forming device; and a pressurization spring unit 40 that applies a force for pressurizing the recording material S to the pressure roller 62 when the fixing unit 14 is mounted to the body 1, and cancels the force for pressurizing the recording material S from the pressure roller 62 when the fixing unit 14 is removed from the body 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement in a heating device of a film heating system / pressure contact member drive type. The present invention also relates to an image forming apparatus provided with the heating device as an image heating unit.

  11 to 13 are views showing an image heating and fixing unit as a conventional film heating method / pressure member driving type heating device. FIG. 11A is a side view of the fixing unit in the pressure contact state, and FIG. 11B is a side view of the fixing unit in the pressure release state. FIG. 12 is a longitudinal front view of the fixing unit in a press-contact state, with the middle portion omitted and partly cut away. FIG. 13 is an enlarged cross-sectional model view of a main part taken along line (10)-(10) in FIG.

  Reference numeral 64 denotes a fixing frame, and 58 denotes an upper plate disposed on the upper side of the side plate 64. The side plate 64 can freely open and close around a fulcrum 65.

  62 is an elastic pressure roller as a pressure contact member, and both end portions of the core metal 62A of the pressure roller are rotatably supported between the front and back side plates of the side plate 64 via bearings 63. It is set up. Reference numeral 140 (FIG. 12) denotes a pressure roller gear fixedly attached to the inner end of the core bar 62A. Reference numeral 141 denotes a drive system idler gear (not shown) meshed with the pressure roller gear 140.

  Reference numeral 50 denotes a film guide unit (heating assembly) disposed in parallel with the pressure roller 62 above the pressure roller 62. The film guide unit 50 has a film guide member 52. A ceramic heater 53 is provided on the lower surface of the film guide member 52 as a heating body fixed and held along the length of the film guide member 52. A cylindrical heat-resistant film (sheet) 54 is loosely fitted on the film guide member 52. Inside the film guide member 52, a U-shaped heater stay 51 having a transverse section downward is inserted. Flange members 55 and 55 for restricting the film ends on the front side and the back side are fitted on the outwardly extending portions 51a and 51a on the front side and the back side of the heater stay 51, respectively. The film guide member 52 holds the ceramic heater 53 and guides the movement of the film 54 from the inside. The heater stay 51 is a rigid member that reinforces the film guide member 52 from the inside, that is, the side opposite to the ceramic heater holding side.

  The film guide unit 50 is disposed between the front side plate and the back side plate of the side plate 64 so as to be movable in the vertical direction. The outward projecting portions 55a and 55a of the flange members 55 and 55 for regulating the film end portions are engaged with the longitudinal guide slit portions 64a and 64a provided on the side plates of the side plate 64, respectively.

  Reference numerals 56 and 57 denote a pressure spring and a pressure member of the film guide unit 50 disposed on the front side and the back side of the upper plate 58, respectively. The pressure member 57 has a vertical axis, a pressure seat provided at the lower end of the vertical axis, and a narrow neck provided at the upper end of the vertical axis. The narrow neck portion is inserted into the hole provided in the upper plate 58 from below, and a retaining head is attached to the upper end portion, so that the upper plate 58 is supported with a degree of freedom of movement in the vertical direction. The pressure spring 56 is contracted between the pressure seat portion of the pressure member 57 and the upper plate 58.

  Reference numeral 60 denotes an upper frame closing spring which is provided between the spring hooks 64b and 58b provided on the side plate 64 side and the upper plate 58 side on the side opposite to the fulcrum 65 side of the upper plate 58.

  In the free state, the upper plate 58 is closed to the side plate 64 around the fulcrum 65 by the pulling force of the spring 60, and as shown in FIG. It is in a state of being accepted by. In this upper frame closed state, the pressure members 57 and 57 of the upper plate 58 are brought into a pressurized state by the compression reaction force of the pressure spring 56 with the pressure seats contacting the upper surfaces of the outwardly projecting portions 55a and 55a. It has become. The upper frame closing spring 60 attracts the upper plate 58 to the closing position with a force stronger than the spring pressure of the pressure springs 56, 56 with the fulcrum 65 as the center of the pivot.

  The film guide unit 50 is pressed against the upper surface of the pressure roller (pressure contact member) 62 with a predetermined pressing force by the compression reaction force of the pressure springs 56, 56, and the ceramic heater 53 and the pressure roller 62 A fixing nip portion N having a predetermined width is formed with the film 54 interposed therebetween.

  The rotational force of the drive system (not shown) is transmitted to the pressure roller 62 via the idler gear 141 and the pressure roller gear 140, and the pressure roller 62 is rotationally driven in the counterclockwise direction indicated by the arrow in FIG. The

  A rotational force acts on the film 54 at the fixing nip N by the rotational driving of the pressure roller 62. Then, the inner surface of the film 54 comes into close contact with the lower surface of the ceramic heater 53 at the fixing nip portion N and slides around the outer periphery of the film guide member 52 in the clockwise direction indicated by the arrow.

  The flange members 55 on the front side and the back side receive the film end on the inner surface side thereof, and restrict the shift in the axial direction accompanying the rotation of the film 54.

  The ceramic heater 53 is a heater having a low heat capacity as a whole based on a ceramic heater substrate such as alumina and an energization heating resistor pattern such as silver palladium (Ag / Pd) formed on the heater substrate surface. From the energizing circuit to the energizing heating resistor pattern, the temperature is quickly raised by energizing the energizing heating resistor pattern, and the heater temperature is adjusted to a predetermined fixing temperature by a temperature control circuit including a heater temperature detecting element such as a thermistor. The power supply is controlled.

  In FIG. 12, reference numeral 67 denotes an electrical connector that is fitted to the front-side outward projecting portion of the film guide member 52. The power supply terminal and the temperature detection terminal on the ceramic heater 53 side are connected to the power supply circuit and the temperature control circuit (not shown). (Lead wire) Electrical communication is made via 67a.

  Thus, the pressure roller 62 is driven to rotate, and the film 54 is driven to rotate accordingly, and power is supplied to the ceramic heater 53 so that the heater temperature rises to a predetermined fixing temperature and is adjusted. The recording material S (FIG. 13) as the heated material on which the unfixed toner image T is formed is conveyed from the image forming unit side to the fixing unit. Then, it is guided by the entrance guide portion 108 and introduced between the film 54 and the pressure roller 62 in the fixing nip portion N, and is nipped and conveyed through the fixing nip portion N. The unfixed toner image T is recorded on the recording material S by the heat applied from the ceramic heater 53 via the film 54 and the pressure applied to the fixing nip N in the process in which the recording material S is nipped and conveyed through the fixing nip N. It is heat-pressure-fixed as a permanently fixed image on the surface S.

  The recording material S exiting the fixing nip N is separated from the surface of the film 54 at the separation point, guided by the lower guide portion 107, and discharged and conveyed.

  In FIG. 11, reference numeral 59 denotes a movable arm for releasing pressure, which is arranged so as to be rotatable about a fulcrum 66 with respect to the side plate 64. When the apparatus is stopped while the recording material S is sandwiched in the fixing nip N for some reason, the upper frame is closed by moving the movable arm 59 around the fulcrum 66 in the counterclockwise direction and the pulling force of the spring 60 Rotating operation against the closing force. Then, as shown in FIG. 11B, the upper plate 58 is opened and rotated from the side plate 64 around the fulcrum 65 by the other arm portion 59a of the movable arm 59. By opening and turning the upper plate 58, the pressurizing member 57 supported on the near side and the far side of the upper plate 58 is lifted. Then, the pressurizing seat portion of the pressurizing member 57 is separated from the upper surfaces of the outwardly projecting portions 55a and 55a of the flange members 55 and 55 that regulate the film end portions on the near side and the far side of the film guide unit 50. As a result, the pressure contact state of the film guide unit 50 with the pressure roller 62 is released. That is, the nip pressure at the fixing nip portion N is released. As a result, the recording material sandwiched in the fixing nip portion N can be pulled out and removed.

  After the recording material is removed, the movable arm 59 is returned and rotated, so that the upper plate 58 is again closed with respect to the side plate 64 as shown in FIG. Then, the pressure seats of the pressure members 57, 57 on the near side and the deep side of the upper plate 58 are brought into contact with the upper surfaces of the outwardly projecting portions 55a, 55a and are brought into a pressurized state by the contraction reaction force of the pressure spring 56. Become. That is, the film guide unit 50 returns to the pressure contact state in which the film guide unit 50 is again pressed against the pressure roller 62 with a predetermined pressing force.

JP 2003-140482 A JP-A-8-129318 JP-A-6-32482

  The fixing unit described above includes a pressure spring for pressing the heating unit against the pressure roller in the fixing unit, and a pressure releasing member for releasing the applied pressure during the jam processing. Therefore, even if the fixing unit is removed, the pressure contact state is continued as it is. For this reason, if the unit is left as it is, the fixing film and the pressing portion of the pressure roller are set in a press-contact shape, and unevenness of the horizontal line may occur due to uneven fixing and rotational unevenness at the start of use. In the shipping form as the fixing unit, there is a case in which a measure is taken to cope with the case by separately adding a packing material so as to maintain the released state. Also, the nip pressure is released by accessing the pressure release member during jam processing, but because it is configured in the fixing unit, the operation part tends to be small, visibility is impaired, or it is difficult to operate It was difficult to improve operability because it could only be placed in As an improvement in operability, there is a configuration in which the nip pressure release mechanism of the fixing unit is interlocked with the opening and closing of the door to access, but the connection with the link member is necessary, and the fixing unit can be arranged without impairing the detachability. Difficult. For this reason, the pressure may be released by operating the release lever directly at the time of jam processing, and the operability may be improved by interlocking with the door only to return from the released state.

  Accordingly, an object of the first invention according to the present application is to provide a mechanism that realizes a configuration that prevents pressure between the heating unit and the pressure roller at a low cost while the fixing unit is detached from the apparatus main body. Is to provide.

  The object of the second invention according to the present application is to provide a link mechanism that links the nip pressure application and release mechanism of the fixing unit with the door during jam access without impairing the detachability of the fixing unit. .

  An object of the third invention according to the present application is to provide a configuration in which the heating device is firmly fixed to the main body device, and at the same time, the attachment / detachment operation can be performed with a weak force at the time of attachment / detachment.

  A typical means in the present invention for solving the above-described problem is an image forming apparatus for forming an image on a recording material, and includes a pressure contact member for applying a pressure contact force to the recording material. A pressure unit detachably attached to the main body of the forming apparatus, and when the pressure unit is attached to the main body, the pressure unit applies a force for applying a pressure contact force to the recording material; When the pressure unit is detached from the main body, pressure applying means for releasing the pressure contact force applied to the recording material by the pressure unit is provided.

  In the present invention, it is possible to realize a configuration in which pressure is not applied between the heating unit and the pressure roller in a state where the fixing unit is removed. A mechanism for applying and releasing the nip pressure of the fixing unit can be provided without impairing the detachability of the fixing unit. Furthermore, the fixing unit can be firmly fixed to the main body.

[First Embodiment]
FIG. 1 is a schematic configuration diagram of an image forming apparatus of the present invention. The image forming apparatus of this embodiment is a laser beam printer using a transfer type electrophotographic process.

  In the main body (main body portion) 1 of the image forming apparatus, the video controller board 4 creates an image signal based on information transmitted from an external information device such as a personal computer or a word processor. Here, various electronic components installed on the video controller board 4 are not shown.

  Then, a laser beam L corresponding to the image signal generated by the video controller board 4 is irradiated onto the photosensitive drum 6A in which the laser scanner 5 rotates clockwise, and electrostatic latent images are sequentially formed on the photosensitive drum 6A. Form. The photosensitive drum 6 </ b> A is disposed in the process unit 6. In addition to the above-described photosensitive drum 6A, the process unit 6 is also provided with a charger, a toner developing device, a cleaning device, and the like that uniformly charge the photosensitive drum 6A to a predetermined polarity and potential. Is omitted.

  The electrostatic latent image formed on the photosensitive drum 6A is successively visualized by toner supplied from a developing device in the process unit 6 and conveyed to a transfer portion between the photosensitive drum 6A and the transfer roller 7. Is done.

  On the other hand, the recording materials S loaded and stored in the feeding cassette 8 are sequentially fed from the uppermost recording material one by one to the feeding path 10 by the half-moon-shaped feeding roller 9 that rotates once counterclockwise. Then, it is conveyed by the conveying roller pair 11 to the registration roller pair 12 whose rotation is stopped.

  The recording material S that has reached the registration roller pair 12 is continuously conveyed until the predetermined loop is formed after the leading end of the recording material S hits the nip of the registration roller pair 12 to correct the skew state. Made.

  The recording material S that has been corrected in the skew state is conveyed to the transfer portion by the registration roller pair 12 that starts rotating at the timing of aligning the position with the toner image on the photosensitive drum 6A. As a result, the toner image on the photosensitive drum 6A is transferred onto the sheet surface.

  The recording material S after the transfer of the toner image passes through the conveyance guide 13 and is conveyed to the fixing unit 14, where the transferred toner image is fixed on the sheet surface.

  The recording material S that has completed the fixing process of the toner image passes through a conveyance path formed by the conveyance surface 16 and the swing guide 24 facing the recording surface 16 when the printing surface is stacked downward. Then, it is discharged onto the face-down discharge tray 17 at the top of the main body 1 by a face-down discharge roller 19 having a drive source (not shown) and a roller 25 that is driven in pressure contact with the roller.

  When the printing surface is stacked upward, a rear cover (cover) 22 provided on the housing 2 and capable of opening and closing is opened as indicated by an arrow A with the rotation center 23 as a fulcrum. Then, the printing surface of the recording material is discharged upward onto the rear cover 22 by the face-up roller 18 provided with a drive source and the roller 15 driven.

  Next, the fixing unit (pressure unit) 14 will be described. A film heating type heating apparatus forms a heating nip portion by sandwiching a heat-resistant film between a heating member such as a ceramic heater and a pressure contact member, and covers the film between the film of the heating nip portion and the pressure contact member. Heating material is introduced and nipped and conveyed with the film. Thus, the heating material is heated at the heating nip portion through the heat of the heating body. By reducing the heat capacity of the heating body and the film, an on-demand type apparatus having features such as quick start performance and power saving can be configured. For example, in an image forming apparatus such as a printer, a facsimile machine, and a copying machine, it can be effectively used as a fixing unit that heats and fixes an unfixed image (unfixed toner image) formed and supported on a recording material.

  An endless film (cylindrical or endless belt) is used as the film, and the pressure contact member is driven to rotate and the film is driven to rotate (pressure contact member drive type). As a result, the tension of the film can be reduced, the moving force in the axial direction of the film during film rotation can be reduced, and the film shifting control means can be simplified. Note that, in the image forming apparatus of the present embodiment, the inside of the main body 1 is covered by the housing 2.

  2 to 4 are explanatory diagrams of the configuration of the heating device portion of the image forming apparatus according to the present embodiment.

  2 is a cross-sectional view of the fixing unit that is mounted in the image forming apparatus and is in a pressure contact state, FIG. 3 is a side view of the fixing unit that is mounted in the image forming apparatus and is in a pressure contact state, and FIG. FIG. 6 is a side view of the fixing unit that is removed from the apparatus and is in a pressure released state.

  A pressing force is generated and transmitted by a pressing spring unit (pressure applying means) 40 comprising a spring fixing holding member 31, a screw 35, a pressing spring 56 and a slide holding member 30. That is, the spring fixing holding member 31 fixed to the main body side plate 32 with the screw 35 fixes and holds the upper end side of the pressure spring 56. The lower end side of the pressure spring 56 is slidably held by the slide holding member 30 that slides up and down the slit portion provided in the main body side plate 32. A spring force is produced in the F1 direction and transmitted to the upper plate (pressure receiving member) 58 via the projection 56A of the slide holding member 30. The flange member 55 is pressed downward by the bent portion 58A. The flange member 55 holds the heater stay 51 from both ends, and the heater stay 51 pressurizes the film guide member 52 holding the ceramic heater (heating means, heater) 53 over the entire area in the longitudinal direction. As a result, the ceramic heater is pressed against the pressure roller 62 via the film (endless film) 54. The pressure roller 62 receives a rotational force from the idler gear 33 to which the pressure roller gear 140 is connected to the drive source on the main body side, and rotates while being pressed against the film, thereby rotating the film. A sheet material to be fixed is conveyed between the rotating film and the pressure roller. By the press contact force, the heat generated from the ceramic heater 53, and the rotation of the pressure roller 62 and the film 54, they are sequentially conveyed and discharged while being fixed.

  With reference to the side views of FIGS. 3 and 4, pressure release when the fixing unit 14 detachable from the main body 1 is removed will be described. FIG. 3 is a view of the same state as that of the cross section of FIG. 2 as viewed from the side. The pressing force F1 of the pressure spring unit 40 attached to the main body is transmitted to the upper plate 58. The heating device is positioned by front and rear insertion portions 41 and 42 and fixed by upper and lower screws 38 and 39. The fixing unit 14 can be pulled out and removed in the direction of the arrow Y4 as shown in FIG. 4 by opening the rear cover 22 in the direction of the arrow A and removing the screws 38 and 39 in the directions of the arrows Y2 and Y3. The heating device in the detached state shown in FIG. 4 does not receive pressure because the pressure spring unit 40 is on the image forming apparatus side. The upper plate 58 is acted on the arrow Y6 from the flange portion of the film guide unit, and the upper plate rotates in the Y7 direction. To prevent the upper plate 58 from opening too much, the rear end portion 58B of the upper plate 58 is prevented from abutting against the end portion 44A of the heating device side plate 44. At the same time that the heating device is removed from the image forming apparatus, the pressure spring unit 40 is attached to the image forming apparatus side, so that no pressure is applied, and the ceramic heater 53 is removed from the film 54 and the pressure roller 62. It will not be in pressure contact. Therefore, in a state where the fixing unit is removed, it is possible to prevent deformation caused by holding the film 54 and the pressure roller 62 at one place while being pressed against the ceramic heater 53. Thereby, it is possible to prevent occurrence of uneven fixing caused by a difference between the deformed portion and the non-deformed portion.

[Second Embodiment]
5 to 8 are block diagrams of an image forming apparatus according to the second embodiment of the present invention. The same parts as those of the image forming apparatus of the first embodiment described above are denoted by the same reference numerals, and redundant description is omitted.

  The image forming apparatus of the present embodiment is obtained by adding a pressure release link mechanism (link mechanism) to the pressure spring unit 40 of the first embodiment described above. 5 to 8 are partial perspective views in a state in which the side plate surface of the image forming apparatus main body is removed so that the pressure release link mechanism can be seen. The upper end of the pressure spring 56 is fixed to the spring fixing holding member 31, and the lower end presses the upper plate 58 of the fixing unit 14 via the slide holding member 30. The pressure release link mechanism is provided with arms at the front and rear. On the front side (right side in the figure), there is an arm 72 that is swingably held around a fulcrum 74 fixed to a side plate (not shown). Further, a slit 72B is provided on the front side of the arm 72, and a link arm 70 having a boss 73 that moves in the slit 72B is held swingably with a fulcrum 71 fixed to a side plate (not shown). .

  Also on the rear side, the arm 76 is held so as to be swingable around a fulcrum 75 fixed to a side plate (not shown). The arm 76 is pressed downward by a tension spring 78 by a hook 77 coming out of the side plate, and a position of the arm 76 is regulated by abutting against the abutting portion 80 of the rear cover 22 with a roller 79 at the tip.

  FIG. 6 is a partial perspective view for illustrating the configuration of the slide holding member 30 and the main body side plate 32. The main body side plate 32 has a slit hole 32B. The upper slit width is wider than the lower slit width, and the slide holding member 30 is lowered after being inserted into the upper slit, so that it is regulated by the retaining portion 30B to the rear side in the figure in the lower slit. It becomes. The slide holding member 30 is held movably up and down in the lower slit. After the slide holding member 30 is mounted, the upper and lower ribs 31B for positioning the spring fixing holding member 31 holding the pressure spring 56 are inserted into the upper slit portion, and the spring fixing holding member is inserted from the back side in the figure with the screw 35. 31 is fixed to the main body side plate 32.

  FIG. 7 is a partial perspective view showing a state of pressure release by the arm operation on the front side (right side in the drawing). When the link arm 70 is lifted upward, it rotates in the B1 direction, and the boss 73 pushes down while sliding the slit groove of the arm 72, and the arm 72 is swung in the B2 direction around the fulcrum 74. As the arm 72 swings in the B2 direction, the distal end portion 72C lifts the slide holding member 30 in the B3 direction. Thereby, the spring force is not applied to the upper plate 58, and the pressure is released.

  By connecting the link arm 70 to the front door, the nip pressure can be released in conjunction with the opening and closing of the front door.

  FIG. 8 is a partial perspective view showing a state where the rear arm 22 in the rear side (left in the figure) is opened and the rear arm is interlocked to perform a pressure releasing operation.

  The rear cover 22 is rotatably held at a fulcrum 22A and swings in the direction of the arrow D1 to open the cover. At that time, the abutting portion 80 attached to the rear cover 22 similarly swings backward. Since the roller 79 attached to the tip of the rear arm 76 is pulled downward by the tension spring 78 shown in FIG. 5, the roller 79 moves while rolling on the rib surface. It swings around D75 in the direction D2. Thereby, the front end 76B of the arm swings in the direction D3, so that the slide holding member 30 is lifted and the pressure is released. By interlocking with the opening operation of the rear cover 22, when a jam occurs at the fixing nip portion, the fixing nip pressure is released by simply opening the rear cover 22, and the jammed paper can be easily removed. In addition, the fixing film, the heater, and the pressure roller can be processed without applying stress due to the applied pressure when removing the paper. As a result, a large strength is not required, so that the fixing film can be reduced in cost, for example, by reducing its film thickness.

[Third Embodiment]
9 and 10 are diagrams for explaining the configuration of a fixing unit according to a third embodiment of the present invention. The same parts as those of the fixing units of the first and second embodiments described above are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 9 is a partial perspective view showing only the vicinity of the fixing unit attachment portion on the image forming apparatus side in order to explain a method of mounting the fixing unit on the image forming apparatus of the present embodiment. Only the front side in the figure will be described, and description of the back side of this unit will be omitted, but it has a substantially symmetrical shape with the front side, and the mounting part and pressurizing mechanism are mounted symmetrically. is there. The side plate 64 of the fixing unit 14 includes a protrusion 86 that determines a vertical position when the fixing unit 14 is attached to the main body 1 and a protrusion (protrusion) 85 that determines a position in the front-rear direction. By inserting the protrusion (protrusion part) 86 of the fixing unit 14 into the hole (insertion hole) 83 in the main body frame 82 of the main body 1 as indicated by an arrow E1, the vertical direction is regulated. By inserting the protruding portion 85 into a hole (insertion hole) 84 in the main body frame 82 as indicated by an arrow E2, the front-rear direction is regulated. Thereafter, the fixing unit is firmly fixed by passing the screw 87 through the hole 88 of the side plate 64 and fixing it to the hole 99 of the main body frame 82 as shown by an arrow E3. Depending on the type of the screw 87, the hole 99 is inserted when the female screw is cut in advance or when the screw 87 is inserted while the screw is cutting the female screw. As shown in FIG. 9, when the fixing unit 14 is taken out from the main body 1, the abutment portion 90 is moved outward (arrow E5) to release the stopper, and the upper plate 58 is moved to the side plate 64. Is opened in the direction of arrow E4 with the notch hole 89 as a fulcrum. As a result, the jammed paper staying inside the fixing unit can be removed. That is, since the pressurizing mechanism is on the main body 1 side and not on the fixing unit 14 side, the fixing unit 14 can easily open and close the upper plate 58 as long as it is removed from the main body 1. For this reason, the jam handling property of the fixing unit and the replacement of the parts inside the fixing unit can be easily performed. Further, when the fixing unit 14 is removed, the roller 79 of the arm 76 moves to the pressure release position in conjunction with the rear cover 22. For this reason, when the fixing unit 14 is removed, the fixing unit 14 is not affected by the applied pressure or can be pulled down to a detachable force, so that the fixing unit can be attached and detached satisfactorily.

  FIG. 10 is a partial cross-sectional view in which the side plate on the main body side is removed so that the state where the fixing unit 14 is mounted on the main body 1 and the pressure roller 62 is driven while receiving the applied pressure can be seen.

  In the fixing unit 14, as described in FIG. 9, the protrusion 83 on the side plate 64 is inserted from the direction of arrow E1, the vertical position in the figure is restricted, and the protrusion 85 is inserted in the direction of arrow E2. The lateral position is restricted.

  The gears rotate in the directions of G6 and G4 due to the rotational force transmitted from the drive source (not shown) via the gears 91 and 92 on the main body side. As a result, the pressure roller gear (first gear) 93 on the fixing unit 14 side rotates in the G5 direction, and the driving force then transmits the drive to the roller on the downstream side of the pressure roller. The gear 37 is rotated. Here, the pressure roller gear 93 receives a force in the G2 direction when driving is transmitted from the gear (second gear) 91 on the main body side. The force in the G2 direction is received at the insertion portion by the projection 85 of the side plate 64 inserted into the main body frame in a direction substantially perpendicular thereto. Further, the arrow G1 indicating the direction of the spring force of the pressurizing spring 56 is also substantially perpendicular to G2, so that a driving force does not act on the applied pressure. Further, since the direction of the arrow E2 indicating the insertion direction of the protruding portion 85 is disposed substantially parallel to the direction of the arrow G1 indicating the pressing force direction, the pressing force exerts an action of preventing the protruding portion 85 from coming off. . For this reason, in this figure, the fixing unit 14 is fixed to the main body frame 82 with screws 87. However, depending on the important balance between the applied pressure and the fixing unit, screw fixing may be unnecessary. Is possible. This makes it possible to eliminate screws when the fixing unit is attached / detached, and is effective in reducing the cost due to the serviceability and jam handling of the fixing unit and the fact that screws are unnecessary.

[Other Embodiments]
1) The ceramic heater 53 may be, for example, an electromagnetic induction heating member.

  2) The image forming apparatus of the present invention is not limited to the image heating and fixing unit as in the embodiment. For example, the present invention can be applied to an image heating apparatus that heats a recording material carrying an image to improve the surface properties such as gloss, and an image heating apparatus that performs a hypothetical process. Further, the present invention can also be applied to a heating device for feeding a material to be heated such as a sheet-like material to perform a drying process, a laminating process, and a wrinkle removing process, a heating apparatus for drying used in an inkjet printer, and the like.

1 is a configuration model diagram of an image forming apparatus according to a first embodiment of the present invention. 1 is a partial cross-sectional view of a vicinity of a heating device of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a side view showing a pressure contact state in which a heating device is mounted in the vicinity of the heating device of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a side view showing a state where the heating device is removed and the press contact is released in the vicinity of the heating device of the image forming apparatus according to the first embodiment of the present invention. FIG. 10 is a partial perspective view of the vicinity of the heating device in which the main body side plate is removed so that the state where the pressurizing unit release mechanism is in pressure contact can be seen in the vicinity of the heating device of the image forming apparatus according to the second embodiment of the present invention. . FIG. 6 is a partial perspective view of the vicinity of the heating device in which the main body side plate is attached to FIG. 5 so that the slide portion of the pressurizing unit release mechanism is visible in the vicinity of the heating device of the image forming apparatus according to the second embodiment of the present invention. is there. FIG. 9 is a partial perspective view of the vicinity of the heating device so that the state in which the first pressure contact of the pressurizing unit release mechanism is released by removing the main body side plate in the vicinity of the heating device of the image forming apparatus according to the second embodiment of the present invention. It is. In the vicinity of the heating device of the image forming apparatus according to the second embodiment of the present invention, the main body side plate is removed and the state where the first and second pressure contacts of the pressurizing unit releasing mechanism are released can be seen. It is a fragmentary perspective view. FIG. 10 is a perspective view illustrating a state where a heating device is mounted on an image forming apparatus in a state where pressure contact is released in the vicinity of the heating device of an image forming apparatus according to a third embodiment of the present invention. FIG. 10 is a side view showing a state when driving is being transmitted to a heating device in a pressure contact state in the vicinity of the heating device of an image forming apparatus according to a third embodiment of the present invention. FIG. 7 is a side view showing a specific example of a fixing unit as a heating device of a film heating method and a pressure member driving type in a conventional example, (A) is a side view of the fixing unit in a pressure contact state, and (B) is a pressure release. It is a side view of the fixing unit in a state. FIG. 8 is a longitudinal front view of a fixing unit in a pressure contact state in a conventional example, with a middle portion omitted and partially cut away. FIG. 13 is an enlarged cross-sectional model view of a main part taken along line (10)-(10) in FIG.

Explanation of symbols

S ... Recording material 1 ... Main body 2 ... Housing
14… Fusing unit
22… Cover
40… Pressure spring unit
53… Ceramic heater
54… Film
58… Upper plate
62… Pressure roller
83, 84… holes
85, 86 ... Projection
91, 92 ... Gear

Claims (7)

An image forming apparatus for forming an image on a recording material,
A pressure unit having a pressure contact member for applying a pressure contact force to the recording material, and detachable from a main body of the image forming apparatus;
When the pressurizing unit is attached to the main body, the pressurizing unit applies a force for applying a pressing force to the recording material, and when the pressurizing unit is detached from the main body. An image forming apparatus comprising: a pressure applying unit that releases a pressure contact force applied to the recording material by the pressing unit. A housing covering the inside of the image forming apparatus;
An openable / closable cover provided on the housing;
The link mechanism according to claim 1, further comprising: a link mechanism that releases the pressure contact force applied to the pressure contact member by the pressure applying means when the cover is opened in conjunction with opening and closing of the cover. Image forming apparatus.   The image forming apparatus according to claim 1, wherein the pressurizing unit further includes a heating unit that applies heat to the recording material. The pressure contact member has a pressure roller,
The image forming apparatus according to claim 3, wherein the heating unit includes a heater that generates heat, and a cylindrical endless film sandwiched between the pressure roller and the heater. The pressure applying means has a pressure spring provided on the main body,
The pressure unit includes a pressure receiving member that receives pressure from the pressure spring when the pressure unit is attached to the main body, and the recording material and the endless film are moved by the pressure received by the pressure receiving member. The image forming apparatus according to claim 4, wherein the image forming apparatus is pressed between the pressure roller and the heater. The pressure unit has a first gear for driving the pressure roller,
The main body has a second gear that meshes with the first gear and transmits a driving force when the pressure unit is mounted on the main body.
The direction of the force by which the second gear pushes the first gear when the first gear and the second gear mesh with each other and the direction of the force applied to the pressure roller by the pressure applying means are substantially perpendicular. The image forming apparatus according to claim 4, wherein the image forming apparatus is an image forming apparatus. The pressure unit has a protrusion for positioning,
The main body has an insertion hole for inserting the protrusion,
The direction in which the protrusion is inserted into the insertion hole is substantially parallel to the direction of the pressure applied to the pressure roller by the pressure applying unit. Image forming apparatus.

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