CN103034105B - The fixation unit of fixing ink powder image - Google Patents

Abstract

The present invention discloses a fixing unit for fixing a toner image, comprising: a heating roller; a pressure roller capable of making pressure contact with the heating roller, and one of the heating roller and the pressure roller can be drawn out along the axial direction of the roller; and an auxiliary A unit connecting portion to which an auxiliary unit for assisting extraction of the roller is detachably attached and the auxiliary unit connecting portion is provided at an end portion in a drawing-out direction of the roller.

Description

Fixing unit that fixes the toner image

This application is an invention patent with the application number 201010002147.6, the application date is January 07, 2010, and the invention name is "fixing unit for fixing toner image, roller replacement auxiliary tool for fixing unit for fixing toner image, and image forming device" Divisional application of the application.

technical field

The present invention relates to an image forming apparatus such as a laser beam printer, and more particularly, to a toner image fixing unit of the image forming apparatus, a roller replacement aid of the toner image fixing unit, and a roller replacement method.

Background technique

A known fixing unit of an image forming apparatus such as a laser beam printer and a copying machine holds a toner image (toner image) on its front surface by heating and pressing and simultaneously transfers a recording medium of the toner image to heat rollers and pressure The recording medium is held between rollers to fix the toner image on the recording medium.

Inside the heating roller, a plurality of lamps are provided as heat sources. In general, a pattern forming apparatus that has a high printing speed and is suitable for storing high-ream weight recording media requires high heat capacity for fixing toner images and thus must maintain a heating roller at a certain temperature or higher, which in turn requires a higher fixing temperature.

When a maintenance technician replaces the heat roller because the heat roller kept at a high temperature reaches the end of its service life, he or she stops the operation of the image forming apparatus, draws out from the fixing unit after cooling the heat roller itself to a certain degree enough to perform the replacement operation heat roller, and replace the heat roller with a new one. However, in this case, it takes time to cool the heating roller and greatly reduces the operating efficiency. Furthermore, this not only leads to a drop in operational efficiency due to the stoppage of the image forming apparatus for a certain period of time, but also results in a huge cost for replacement maintenance operations.

Recently, there is a need for an image forming apparatus suitable for high printing speed, high image quality, and various papers. In addition, the fixing unit has been required to use some type of heating roller such as one having thin PFA resin etc. applied on its front surface for rapidly supplying heat for fixing toner images when a high printing speed is required , a heating roller having silicone rubber etc. coated on its front surface for minimizing bleeding and damage of the toner image at the fixing point when high image quality is required, and when a certain degree of image quality and roller are required For durability, there is a heating roller such as PFA resin coated on the silicone rubber layer.

In order to respond to such demands in the image forming apparatus, it is necessary to change the heating roller accordingly. Although there are some differences according to types, the heating roller basically has a high heat capacity and needs to be cooled for a long time to be replaceable from a high temperature state where the heating roller is kept to provide heat required for optimal toner fixing. Replacement of the heating roller is discussed in, for example, Patent Document 1 (Japanese Patent Application National Laid-Open No. 5-504633).

1 and 2 are partial sectional views of a fixing unit described in Patent Document 1 and perspective views of the fixing unit showing a heating roller being replaced.

FIG. 1 is a partial sectional view of a fixing unit described in Patent Document 1. As shown in FIG. As shown in FIG. 1 , one end of the heating roller 100 is supported by a frame 102 through a support flange 101 . The support flange 101 has a bearing 103 , and the bearing 103 is installed in the open end of the heating roller 100 together with a center member 104 . Although not shown in FIG. 1 , the other end of the heating roller 100 is also supported by a support flange through a bearing.

The support flange 101 is secured to the frame 102 by thumbscrews 106 . The supporting flange 101 is fixed to the clamping claw 108 by the thumb screw 107, and the clamping claw 108 is used to set the position of the heating roller 100 when the heating roller 100 is replaced.

Inside the heat roller 100, a plurality of radiator modules 105 are arranged. The first ends of the plurality of radiator modules 105 are clamped at the center of the supporting flange 101 by the clamping part 109 . Although not shown in FIG. 1 , the other ends of the plurality of radiator modules 105 are also indirectly supported by the support flanges through clamping members.

As shown in FIG. 1 , the connectors 110 provided at the ends of the plurality of radiator modules 105 protrude outwards more than the support flange 101 where the plurality of radiator modules 105 are clamped on the support flange. 101 Central. The supporting flange 101 and the handle 111 are integrally provided for replacing the heating roller 100 . A handle 111 is provided so as to span the connectors 110 of the plurality of heat sink modules 105 protruding from the support flange 101 .

As shown in FIG. 2 , when replacing the heating roller 100 , the operator loosens the thumb screw 106 and draws the heating roller 100 together with the support flange 101 and the like from the frame 102 by holding the handle 111 with one hand.

Generally, the heating roller used in this type of fixing unit is a cylinder having a diameter of about 100 mm and a length of 500 mm or more, which is very heavy. In this case, when the operator draws out the heat roller 100 together with the support flange 101 and the like from the frame 102 by holding the handle 111 with one hand, the drawing operation may not be possible due to the weight and heat of the heat roller 100 and the like. Stablize. Thus, during the replacement of the heating roller 100 , it may be caused that the heating roller 100 comes into contact with other members such as the frame 102 to damage the front surface of the heating roller 100 .

As described above, since the posture of the heating roller 100 becomes unstable and no auxiliary tool is provided for stabilizing the posture of the heating roller 100, in the embodiment disclosed in Patent Document 1, when replacing the heating roller 100, the operator will One hand is placed on the heat roller 100. However, when an operator touches the heat roller 100 at high temperature, he or she is burned or is soiled with toner release agent and lubricating oil adhering to the heat roller 100, which causes a problem in operation.

In addition, since the handle 111 is integrally formed with the support flange 101 clamping the plurality of radiator modules 105 and arranged near the ends of the plurality of radiator modules 105, the handle 111 itself is also at a high temperature. Thus, it is difficult for the operator to hold the handle 111 when replacing the heating roller 100 .

Meanwhile, when the image forming apparatus is in an operating state, the handle 111 is used to rotate and hold the heat roller 100 and is screwed into a connection member (not shown). Thus, the connecting parts and screws are also at high temperature. Therefore, detaching the heating roller 100 from the connecting part is an operation of handling parts including screws at high temperature, which causes problems in workability as well as safety.

Furthermore, a handle 111 is provided in the center of the support flange 101 , which in turn interferes with the replacement of a plurality of radiator modules 105 . Thus, the plurality of radiator modules 105 is limited to be inserted and drawn from another support flange where the handle 111 is not provided, which causes a problem in handling.

In addition, a handle 111 protrudes from the support flange 101 . Thus, space is wasted, which causes a problem in miniaturization of the image forming apparatus.

In addition, when the operator pulls out the heating roller 100 from the frame 102 together with the support flange 101 and the like by gripping the handle 111 with one hand, it may cause the heating roller 100 to come into contact with the frame 102 to damage the front surface of the roller. Thus, the vicinity of the opening of the frame 102 is coated with felt 130 to be protected. However, when the heating roller 100 with the release agent and lubricating oil attached to its front surface slides, stains accumulate on the felt 130 . Thus, the above configuration is ineffective for protecting the front surface of the heating roller 100 .

In addition, it is necessary to attach and detach the felt 130 every time the heating roller 100 is replaced, resulting in complicated replacement operations. In addition, the felt 130 is stained every time the heating roller 100 is replaced, which in turn requires discarding the stained felt 130 and preparing a new felt 130 .

Patent Document 1: Japanese Patent Application National Laid-Open Publication No. 5-504633

Patent Document 2: Japanese Laid-Open Patent Publication No. 6-011984

Contents of the invention

The present invention has been made in view of the above disadvantages and can provide a fixing unit capable of being miniaturized, a roller capable of being replaced, a roller replacement assist tool, a roller replacement method, and an image forming apparatus.

According to a first aspect of the present invention, there is provided a fixing unit including: a heating roller; a pressure roller capable of making pressure contact with the heating roller, one of the heating roller and the pressure roller being able to be drawn out in an axial direction of the roller; and An auxiliary unit connection portion to which an auxiliary unit for assisting extraction of the roller is detachably connected and the auxiliary unit connection portion is provided at an end portion in a drawing out direction of the roller.

According to a second aspect of the present invention, there is provided a fixing unit including: a heating roller; a pressure roller capable of making pressure contact with the heating roller, one of the heating roller and the pressure roller can be inserted and extraction; an opening for replacement formed in the frame opposite to the roller capable of being inserted and extracted; and a support member provided outside the frame and near the opening for replacement to support the roller to be extracted and inserted.

According to a third aspect of the present invention, there is provided an image forming apparatus, comprising: a transfer unit for transferring a toner image on an image carrier to a medium; and the above-mentioned fixing unit; characterized in that the fixing unit has a heating roller and a pressure roller capable of making pressure contact with the heat roller, and causing the medium having the toner image transferred thereon to pass through a gap between the heat roller and the pressure roller to fix the toner image to the medium.

According to a fourth aspect of the present invention, there is provided a roller replacement assist tool for a fixing unit that extracts and replaces one of a heating roller and a pressure roller capable of pressure contact with the heating roller in the axial direction of the roller. The roller replacement auxiliary tool includes a guide shaft detachably attached to the fixing unit to penetrate through an opening formed through the penetration in the axial direction of the roller to be replaced; The auxiliary unit at the end portion of the withdrawing direction of the replaced roller is connected to the part and installed into the end of the guide shaft from the outside to insert and withdraw the roller.

Other objects, features and advantages of the present invention will be more clearly understood from the following detailed description when read in conjunction with the accompanying drawings.

Description of drawings

FIG. 1 is a partial sectional view of a conventional fixing unit;

2 is a perspective view showing a heating roller of a fixing unit being replaced;

3 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention;

4 is a sectional view of the vicinity of a heating roller according to an embodiment of the present invention;

5 is a cross-sectional view at a protruding part attached to a heating roller according to an embodiment of the present invention;

6 is a sectional view at the guide shaft attached to the inside of the heating roller according to the first embodiment of the present invention;

7 is a sectional view at an auxiliary unit inserted into a heat roller according to a first embodiment of the present invention;

Fig. 8 is a cross-sectional view where the protruding part is drawn out from the heating roller;

9A and 9B are cross-sectional views of the auxiliary unit, wherein FIG. 9A is a view showing lever portions of two latches directed outward to each other, and FIG. 9B is a view showing lever portions of two latches directed inwardly to each other;

10 is a partial perspective view of an auxiliary unit according to a first embodiment of the present invention;

11 is a step diagram illustrating a process for replacing a heating roller according to an embodiment of the present invention;

12A and 12B are cross-sectional views showing the relationship between the absorber and the clamping pieces of the clamper taken along the plane X-X in FIG. 7, wherein FIG. 12A is a view where the auxiliary unit is inserted into the heating roller, and Figure 12B is a view where the auxiliary unit is attached to the absorber;

Fig. 13 is a sectional view of a place where an auxiliary unit is attached to a heating roller according to the first embodiment of the present invention;

14 is a sectional view of a heating roller being drawn out according to the first embodiment of the present invention;

15 is a sectional view of a heating roller to be drawn out according to a second embodiment of the present invention;

16 is an enlarged cross-sectional view near a push pin according to a second embodiment of the present invention;

17A and 17B are views showing the relationship between the absorber and the clamping piece of the clamper taken along the plane Y-Y in FIG. 15, wherein FIG. 17A is a view where the auxiliary unit is inserted into the heating roller, and FIG. 17B is the view where the auxiliary unit is attached to the absorber;

18A and 18B are cross-sectional views of an auxiliary unit according to a second embodiment of the present invention, wherein FIG. 18A is a view in which the lever portions of two latches are directed outward to each other, and FIG. 18B is a view in which the lever portions of two latches are directed inward to each other. view;

19 is a partial sectional view for explaining the operation of attaching and detaching the auxiliary unit to and from the heating roller according to the second embodiment of the present invention;

20A to 20F are views showing the backup roller member, wherein FIGS. 20A and 20B are side views and plan views when the backup roller member is in the operating position, and FIGS. 20C and 20D are when the backup roller member is moved from the operating position to the standby position. when, and Figures 20E and 20F are side views and plan views when the backup roller assembly is in the stand-by position;

Fig. 21 is a view showing the arrangement of two auxiliary roller parts with respect to the auxiliary unit;

22 is a step diagram showing a procedure for replacing a heat roller according to a third embodiment of the present invention; and

Fig. 23 is a partial sectional view at a heating roller supported by two supporting roller members according to an embodiment of the present invention.

Detailed ways

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

(The overall configuration of the laser beam printer)

Referring first to FIG. 3, the overall configuration of an electrophotographic laser beam printer to which an embodiment of the present invention is applied will be described.

In FIG. 3 , reference numeral 1 denotes a laser beam printer, and the photosensitive drum 21 rotates in a direction indicated by an arrow in accordance with a printing operation start signal from the controller 22 . The photosensitive drum 21 rotates at a speed equal to the printing speed of the laser beam printer 1 and continues its own rotation until the printing operation stops. When the photosensitive drum 21 starts its own rotation, a high voltage is applied to the scorotron charger 2 . Then, the scorotron charger 2 uniformly charges the front surface of the photosensitive drum 21 with a positive charge, for example.

When power is supplied to the laser beam printer 1, the rotary polygon mirror 3 immediately starts its own rotation. When power is supplied to the laser beam printer 1, the rotary polygon mirror 3 rotates at a constant speed with high accuracy. Light output from a light source 4 such as a semiconductor laser is reflected by a rotary polygon mirror 3 and irradiated onto a photosensitive drum 21 through an f-theta lens 5 in a scanning manner. When text data and graphic data converted into dot images are supplied from the controller 22 to the laser beam printer 1 as an ON/OFF signal of the laser beam, a certain portion of the front surface of the photosensitive drum 21 is irradiated with the laser beam, but the photosensitive drum 21 is not irradiated. Another part of the front surface of the drum 21. At this time, an electrostatic latent image is formed on the front surface of the photosensitive drum 21 .

When the area of the photosensitive drum 21 holding the electrostatic latent image reaches a position on the opposite side of the developing unit 6 , toner is supplied to the electrostatic latent image. For example, positively charged toner is adsorbed to a portion of the photosensitive drum 21 where the charge disappears due to irradiation of a laser beam, which in turn forms a toner image on the photosensitive drum 21 .

The paper transport chain 8 transports the continuous paper (medium to be recorded) 7 accommodated in the paper box (sheet hopper) 11 to a place between the photosensitive drum 21 and the transfer unit 10 in synchronization with the timing at which The toner image formed on the photosensitive drum 21 reaches the transfer position. The toner image formed on the photosensitive drum 21 is attracted to the paper 7 by the operation of the transfer unit 10 , which applies charges having a polarity opposite to that of the toner image to the rear surface of the paper 7 .

Then, the paper 7 is conveyed to the fixing unit 12 by the paper conveying chain 8 , the transfer unit 10 , the paper conveying chain 9 , and the buffer plate 24 . After reaching the fixing unit 12, the paper 7 is preheated by a preheater 13 including a plurality of heaters, and is nipped and conveyed to be heated and pressed by a nip portion having a pair of fixed rollers each Each consists of a heat roller 14 and a pressure roller 15 each including a plurality of lamps 25. In this way, the toner image is melted and fixed to the paper 7 .

The paper 7 fed from the heat roller 14 and the pressure roller 15 is fed to the delivery table 19 by the paper feed roller 16 and simultaneously folded optionally along the perforations by the swing operation of the swing fin 17 . Furthermore, the sheets 7 are stacked on the delivery table 19 so as to be accurately folded by the rotary blade 18 . The area of the photosensitive drum 21 that has passed through the transfer position is cleaned by the cleaning unit 20 and is ready for the next printing operation.

The buffer plate 24 serves to absorb slack or tension caused by the paper 7 when there is a difference in paper conveying speed between the paper conveying chain 9 and the fixing rollers 14 and 15 . Reference numeral 23 is a display screen that displays information based on the status of the laser beam printer 1 during a printing operation. Reference numeral 26 is a web member (web member) capable of contacting and being rolled up from the front surface of the heating roller 14 for coating a toner release agent on the front surface of the heating roller 14 and lubricating oil.

(Structure near the heating roller)

Next, referring to FIG. 4 , the structure in the vicinity of the heating roller 14 of the fixing unit 12 will be described. The heat roller 14 is composed of a metal tube 14a made of, eg, aluminum, and a front surface layer 14b, eg, of polytetrafluoroethylene and silicone rubber, provided on the paper passage area of the peripheral surface of the tube 14a. In regions near openings at both ends of the heat roller 14 , heat transfer preventing members 14 c and 14 d (hereinafter referred to as absorbers) made of, for example, aluminum are fixed one at each end. The absorbers 14 c and 14 d prevent the temperature of the device from rising due to transfer of heat from the plurality of lamps 25 included in the heating roller 14 to the outside of the heating roller 14 .

The ends of the heating roller 14 are supported by the frame 15 of the fixing unit 12 through clamping members 48 and 49 having central members 46 and 47 , respectively.

The clamping member 48 is provided with the central member 46 passing through the bearing 51 , and the central member 46 is inserted into the open end of the heat roller 14 . The bearing 51 can absorb the thermal expansion of the heat roller 14 and the difference between the circumferential support members, wherein a plurality of springs 52 are provided in the axial direction of the bearing 51 and the stopper plate 53 arranged on the end surface inside the clamping member 48 . When assembled with the heated roller 14 , the plurality of springs 52 are slightly compressed to create a gap between the central member 46 and the bearing 51 and brake plate 53 shown in FIG. 4 . Clamping member 48 is secured to frame 50 by a plurality of thumbscrews 54 .

The clamping member 49 is provided with a gear 55 for receiving a driving force from a motor that rotates and drives the heating roller 14, and is rotatably supported by housings 58 and 59 through bearings 56 and 57, respectively. In order to prevent damage and transfer of heat from the heating roller 14 to the central parts 46 and 47 , heat resistant plastic rings 60 are inserted between the corresponding ends of the heating roller 14 and the central parts 46 and 47 . Note that the drive motor is a typical type.

The plurality of lamps 25 as a heat source for the heat roller 14 constitute a lamp box 63 bound by lamp holders 61 and 62 holding corresponding ends of the plurality of lamps 25 . The lamp box 63 is provided at the center inside the heating roller 14 shown in FIG. 4 . In FIG. 4 , reference numeral 31 denotes a stopper 31 , and reference numeral 32 denotes a nail for fixing the stopper 31 . As shown in FIG. 4, the lower end of the stopper 31 faces inwardly of the through hole 59a of the casing 59 in a normal state.

(Removal and attachment of the light box)

Next, with reference to FIG. 5 , detachment and attachment of the lamp box 63 will be described. When a lamp box 63 or heat roller 14 described below is being replaced, a protective member 64 made of, for example, a paper tube is used as shown in FIG. 5 . The outer diameter of the protective member 64 is substantially the same as the inner diameter of the holding member 48 and the inner diameter of the inner cylinder 59 b of the housing 59 . In addition, the inner diameter of the protective member 64 is substantially the same as the outer diameter of the lamp holder 62 . In addition, the length of the protection part 64 is slightly longer than the distance between the left and right frames 50 .

When the lamp box 63 is inserted into the heat roller 14 , the protective member 64 covers one side of the lamp holder 62 , and the right end of the protective member 64 is in contact with the end surface of the other lamp holder 61 . The end portion of the lamp holder 62 has a slope 62 a for facilitating insertion of the protection member 64 .

As shown in FIG. 5 , when the stopper 31 is raised, the stopper 31 is fixed in a higher position by the spike 32 . The lamp box 63 with the attached protective part 64 is inserted from one side of the holding part 48, as indicated by arrow A in FIG. . When a part of the lamp holder 61 comes into contact with the holding member 48, the insertion of the lamp box 63 stops. At this time, the end portion of the protection member 64 in the insertion direction protrudes from the case 59 . Thus, when the rest of the protective member 64 is drawn out in the direction indicated by the arrow A behind the protruding portion of the end portion, the attachment of the lamp box 63 is completed.

When drawing out the lamp housing 63 from the heat roller 14, the protective member 64 is inserted from the side of the through hole 59a of the case 59 as indicated by arrow B in FIG. At this time, the end portion of the protection member 64 in the insertion direction comes into contact with the end surface of the lamp holder 61, and is simultaneously guided by the inner cylinder 59b of the housing 59, the slope 62a of the lamp holder 62, and the holding member 48. . When the protective member 64 is further inserted, the lamp box 63 and the protective member 64 are pushed in the direction shown by arrow B, which in turn makes it possible to extract the lamp box 63 . Therefore, a plurality of lamps 25 can be collectively detached.

As described above, covering the insertion and extraction of the lamp box with the protective member 64 can prevent damage to the plurality of lamps 25 during handling of the lamp box 63 . In addition, insertion and extraction of a plurality of lamps 25 can be performed collectively.

Note that a paper tube as the protective member 64 is preferable because it has thermal insulation properties, predetermined mechanical strength, and is easily available due to its low cost.

(first embodiment)

(Configuration of auxiliary tool for replacing the heating roller)

Next, an auxiliary tool for replacing the heating roller 14 according to the first embodiment of the present invention is described. The auxiliary tool according to this embodiment consists of a guide shaft 30 (see eg FIG. 6 ) and an auxiliary unit 40 (see eg FIG. 7 ).

The guide shaft 30 is made of a rigid metal cylinder. As shown in FIG. 6, the length of the guide shaft 30 is slightly longer than the distance between the left and right frames 50, and the outer diameter of the guide shaft 30 is closely related to the inner diameter of the holding member 48, the inner diameter of the absorber 14d, and the inner circle of the housing 59. The sizes of the inner diameters of the cylinders 59b are substantially the same.

On the side surface of the housing 59 , a plate-shaped stopper 31 for fixing (locking) the guide shaft 30 is slidably held by nails 32 . As shown in FIG. 6, a slit 30a is provided in the circumferential wall of the guide shaft 30 so that the stopper 31 is inserted into the guide shaft 30 when the guide shaft 30 is inserted to a predetermined position.

According to this embodiment, a plate stopper 31 is used, and a slit 30 a is provided in the guide shaft 30 . Alternatively, a spike stopper may be used and a through hole is provided in the guide shaft 30 into which the spike stopper is inserted. In addition, it is also possible to detachably fix the guide shaft 30 to the housing 59 or the like using screws.

Fixing (locking) the guide shaft 30 to a predetermined position as described above makes it possible to smoothly perform the insertion and withdrawal operations of the above-mentioned respective components without causing the guide shaft 30 when inserting and withdrawing the heating roller 14 , the holding member 48 , and the auxiliary unit 40 The position moves.

On the outer circumference of the tip portion of the guide shaft 30 in the insertion direction, an inclined surface 30b for smoothing the insertion of the auxiliary unit 40 and the like is formed. When the guide shaft 30 is fixed to a predetermined position, the tip portion (inclined surface 30 b ) of the guide shaft 30 in the insertion direction protrudes slightly outward from the outer surface of the frame 50 (see FIG. 8 ).

As shown in FIGS. 9A and 9B , the auxiliary unit 40 consists of a unit main body 45 , two latches 41 rotatably attached to the side surfaces of the unit main body 45 , and two latches 41 that transmit the movement of the two latches 41 to a holder 43 . A shaft 42, a clamper 43 having one end connected to the shaft 42 and the other end folded toward the outside, a coil spring 44 absorbing member tolerances to ensure fixation to the heating roller 14, and a handle attached to the outer surface of the unit main body 45 66 (see Figure 10) composition. Note that as shown in FIG. 10, the rotational positions of the lever portions 41c of the two latches 41 are offset from the attachment position of the handle 66 on the unit main body 45, which prevents the handle 66 from interfering with the rotational operation of the lever portion 41c. .

An insertion hole 45 b penetrating in the axial direction is provided at the center of the unit main body 45 . A flange 45 c is formed on one side surface of the unit main body 45 . A ring 65 is provided at a position where the open end of the heating roller 14 contacts when the heating roller 14 is being replaced. The inner diameter of the insertion hole 45 b is substantially the same size as the outer diameter of the guide shaft 30 .

The two latches 41 have the same shape. Each of the two latches 41 has a rotating portion 41a formed at one end and a side surface thereof formed in a semicircular shape, a shaft portion 41b disposed on the side of the rotating portion 41a, and a lever portion 41c. The inside is thus deviated from the center in the thickness direction of the rotating portion 41a, and the lever portion 41c is disposed opposite to the rotating portion 41a. The two latches 41 are attached to the unit main body 45 so that the rotating parts 41a are opposed to each other across the insertion hole 45b.

A first end of the shaft 42 is connected to a corresponding shaft portion 41 b of the latch 41 . In addition, at the other end of the holder 43 opposite to the end connected to the shaft 42 , the holding piece 43 a is folded so as to oppositely face the inner side surface 45 a of the unit main body 45 . As shown in FIGS. 9A and 9B , the coil spring 44 is inserted between the stepped spring receiving portion 45 d and the latch 44 . The shaft 42 is inserted into the spring 44 , and the latch 41 is elastically biased to the outward direction at all times by the elastic force of the spring 44 . However, each latch 41 has a locking unit 41 d whose side surface is U-shaped (see FIG. 10 ).

Fig. 9A shows that the lever portions 41c of the two latches 41 are directed outwardly from each other. At this time, the shaft portion 41 b of the latch 41 is placed close to the unit main body 45 . Thus, the interval between the clamping piece 43a of the clamper 43 and the inner side surface 45a of the unit main body 45 becomes large, as indicated by L1. As shown in FIG. 7, the interval L1 is slightly larger than the thickness of the absorber 14c. Figure 10 also shows that the lever portions 41c of the two latches 41 are directed outwardly towards each other, as is the case in Figure 9A.

As shown in FIG. 9B , when the lever portions 41 c of the two latches 41 are rotated inwardly of each other, the shaft portion 41 b of the latch 41 moves in a direction away from the unit main body 45 . As the latch 41 moves away from the center, the shaft 42 and the holder 43 also move, which in turn reduces the spacing between the clamping piece 43a of the holder 43 and the inner side surface 45a of the unit body 45, as indicated by L2. Show. The interval L2 is slightly smaller than the thickness of the absorber 14c.

(Process of replacing the heat roller)

Next, a procedure for replacing the heating roller 14 is described. The heat roller 14 is replaced when the heat roller 14 reaches the end of its service life or is to be replaced to meet the needs of the image forming apparatus described above.

FIG. 11 is a step diagram showing a procedure for replacing the heating roller 14 . As shown in FIG. 11 , in step 1, the lamp housing 63 is drawn out from the heating roller 14 by using the protection member 64 . Since this operation is described above with reference to FIG. 5 , a repeated description thereof is omitted here. The extracted lamp box 63 is covered by a rigid protective member 64 . Thus, the lamp box 63 is not inadvertently damaged during its replacement operation.

Next, in step 2, as shown in FIG. 6 , the guide shaft 30 is inserted in the direction shown by arrow B from the through hole 59 a of the housing 59 . The inner cylinder 59 b of the housing 59 , the absorber 14 d , and the clamping member 48 guide and clamp the guide shaft 30 . When the guide shaft 30 is inserted to a predetermined position, the stopper 31 is inserted in the slit 30 a of the guide shaft 30 , thereby completing the attachment of the guide shaft 30 .

Then, in step 3, the thumb screw 54 is loosened to withdraw the holding member 48 holding the central member 46, the bearing 51, the spring 52, the stopper plate 53, etc. in the direction indicated by the arrow B. At this time, the tip portion of the guide shaft 30 protrudes slightly outward from the outer side surface of the frame 50 . Thus, along with the guidance of the guide shaft 30 , the clamping member 48 can be smoothly withdrawn without colliding with the open end of the frame 50 . Note that since the center member 46 is separated from the heat roller 14 when the clamp member 48 is drawn out, the center member 46 and the bearing 51 are brought into contact with the stopper plate 53 by the restoring force of the spring 52 .

In FIG. 6 the guide shaft 30 is attached and the clamping member 48 is being withdrawn, while in FIG. 8 the clamping member 48 has been withdrawn.

Next, in Step 4, by gripping the handle 66, the auxiliary unit 40 is inserted from the side of the tip portion of the guide shaft 30 having the inclined surface 30b. At this time, as shown in FIG. 9A , the lever portions 41 of the latch 41 are directed outward from each other. Accordingly, the interval between the inner side surface 45a of the unit main body 45 and the holding piece 43a of the holder 43 becomes larger, as indicated by L1.

12A and 12B are diagrams showing the relationship between the absorber 14c and the holding piece 43a of the holder 43 taken along the plane X-X of FIG. 7 . FIG. 12A is a diagram showing when the auxiliary unit 40 is inserted into the heating roller 14, and FIG. 12B is a diagram showing when the auxiliary unit 40 is attached to the absorber 14c.

As shown in FIG. 12A, in the inner peripheral portion of the absorber 14c, two cutouts 67 capable of being inserted into the holding piece 43a of the holder 43 are formed so that the two cutouts 67 are opposed to each other. As shown in FIG. 7 , when the auxiliary unit 40 is inserted into the heating roller 14 , the clamping piece 43 a of the clamper 43 passes through the cutout 67 and is placed on the left side of the absorber 14 c in FIG. 7 . When the flange 45c of the unit main body 45 comes into contact with the outer side surface of the frame 50, the insertion of the auxiliary unit 40 is stopped.

When the inserted auxiliary unit 40 is rotated in the direction shown by the arrow in FIG. 12A by gripping the handle 66, the clamping piece 43a of the clamper 43 rotates away from the cutout 67 and faces the side of the absorber 14c as shown in FIG. 12B. Other inner circumference parts instead of cutouts 67 . In other words, the other inner peripheral portion of the absorber 14 c is squeezed between the inner side surface 45 a of the unit main body 45 and the holding piece 43 a of the holder 43 .

When the lever portions 41c of the latch 41 are rotated inwardly with each other as shown in FIG. The inner peripheral portion of the absorber 14c is elastically held between the holding piece 43a of the unit body 45 and the inner side surface 45a of the unit main body 45 . Therefore, the auxiliary unit 40 is attached to the heating roller 14 through the absorber 14c.

Then, in Step 5 , the heating roller 14 at high temperature is drawn out from the image forming apparatus by gripping the handle 66 of the auxiliary unit 40 . At this time, the inner cylinder 59 b of the housing 59 securely holds the guide shaft 30 , and the inner peripheral portion of the absorber 14 d slides on the outer peripheral surface of the guide shaft 30 . Thus, there is no need to pinch portions of the heating roller 14 that are at a high temperature from each other, which enables smooth and safe extraction of the heating roller 14 . Even after the extraction of the heating roller 14, the central member 47 and the clamping member 49 maintain themselves as they are. Fig. 14 shows the heating roller 14 being drawn out.

Next, in Step 6 , the auxiliary unit 40 is attached to the new heating roller 14 for replacement, and the heating roller 14 is loaded by using the guide shaft 30 . Note that the new heat roller 14 is not shown in the figure, but its basic configuration is the same.

Then, in step 7 , the auxiliary unit 40 is drawn out from the heat roller 14 . In step S8 , the clamping member 48 is attached by using the guide shaft 30 . In step 9, the brake 31 is released to withdraw the guide shaft 30 . In step 10 , the lamp box 63 covered with the protective member 64 is inserted into the heat roller 14 , and then the pinch member 48 is drawn out from the heat roller 14 , thereby completing the attachment of the lamp box 63 .

Note that since the attachment of the new heating roller 14 in step 6 is the reverse operation of the extraction of the heating roller 14 in step 5, the extraction of the auxiliary unit 40 in step 7 is the attachment of the auxiliary unit 40 in step 4. The opposite operation of the following, the attachment of the clamping part 48 in step 8 is the reverse operation of the extraction of the clamping part 48 in step 3, and the extraction of the guide shaft 30 in step 9 is the guide in step 2 The attachment of the shaft 30 is the opposite operation, and the attachment of the light box 63 in step 10 is the opposite operation of the extraction of the light box 63 in step 1, and their descriptions are omitted here.

(second embodiment)

A second embodiment of the present invention will be described below with reference to the drawings. Also, in this embodiment, the auxiliary tool consists of a guide shaft 30 and an auxiliary unit 40 (see FIG. 15 ).

The guide shaft 30 is made of a rigid metal cylinder. As shown in FIG. 15 , the length of the guide shaft 30 is slightly longer than the distance between the left and right frames 50, and the outer diameter of the guide shaft 30 is closely related to the inner diameter of the clamping member 48 (see FIG. 6 ), the inner diameter of the absorber 14d, and The inner diameters of the inner cylinder 59b of the housing 59 are substantially the same size. Even when the lamp housing 63 (see FIG. 8 ) is fully withdrawn from the frame 50 of the fixing unit 12 , the guide shaft 30 is configured to be installed in the absorbers 14 c and 14 d that prevent heat transfer from the corresponding ends of the heating roller 14 .

A slit 30 a is formed in a part of the cylindrical portion of the guide shaft 30 . The guide shaft 30 is formed such that a stopper 31 provided in the fixing unit 12 can enter the guide shaft 30 from a direction indicated by an arrow in FIG. 15 when the guide shaft 30 is fixed to the fixing unit 12 . In addition, at an end portion of the guide shaft 30 in the insertion direction, an inclined surface 30b for smoothing the attachment of the auxiliary unit 40 is formed.

When attaching the guide shaft 30 to the fixing unit 12 , the guide shaft 30 is inserted from the rear side (left side in FIG. 15 ) of the image forming apparatus through a through hole 59 a provided in the housing 59 . At this time, the guide shaft 30 is inserted into the fixing unit 12 until the inclined surface 30 b of the guide shaft 30 slightly collides with the front frame 50 (right side in FIG. 15 ) of the image forming apparatus. Then, when the stopper 31 is lowered in the direction shown by the arrow and the stopper 31 is inserted into the slit 30a, the guide shaft 30 is locked (fixed) to a predetermined position.

The auxiliary unit 40 has a unit main body 45 , two latches 41 , a shaft 42 , a holder 43 , a coil spring 44 , a handle 66 and at least two push pins 68 . Two latches 41 are attached to the side surface of the unit main body 45 in a manner capable of being rotated in the direction shown by the arrow and enabling/disabling engagement with the end of the heating roller 14 . The shaft 42 transmits the movement of the latch 41 to the holder 43 . The clamper 43 clamps the absorber 14 c at the inner end of the heating roller 14 between the clamper 43 and the heating roller 14 , thereby engaging the heating roller 14 with the auxiliary unit 40 . The coil spring 44 absorbs component tolerances to ensure fixation to the heating roller 14 . A handle 66 is attached on the outer side surface 45 b of the unit main body 45 . Two push pins 68 are arranged near the outer circumferential portion of the unit main body 45 at regular intervals. According to this embodiment, the push pins are the same number as the latches 41 and are arranged so as to have a spacing of 180° from each other.

Note that the rotational position of the lever portion 41c of the two latches 41 and the arrangement position of the push pin 68 on the unit body 45 are offset from the attachment position of the handle 66, which in turn prevents the handle 66 from being attached to the lever portion 41c (see FIG. 10 ). ) interferes with the rotation operation.

This embodiment differs from the first embodiment in having a push pin (separation unit) 68 provided in the auxiliary unit 40 . The push pin 68 is provided to correspond to a case where the auxiliary unit 40 at a high temperature is not easily drawn out from the heat roller 14 due to heat deformation of the heat roller 14 . In this case, the auxiliary unit 40 is forcibly drawn out manually by gripping the heating roller 14 . However, due to its high temperature, handling the heating roller 14 is dangerous, and it takes time to extract the auxiliary unit 40 from the heating roller 14, which in turn reduces the efficiency of the operation itself. In order to prevent this problem, application of force from the auxiliary unit 40 in the axial direction of the heating roller 14 makes it possible to easily and safely withdraw the auxiliary unit 40 from the heating roller 14 .

As shown in FIGS. 15 and 16 , each push pin 68 is composed of a large-diameter portion 69 relative to the end surface of the heating roller 14 and a small-diameter portion 70 relative to the lever portion 41 c of the latch 41 . A stepped portion 72 is formed at the boundary between the large diameter portion 69 and the small diameter portion 70 . In addition, a lock ring 73 is fixed at a portion near the head portion of the small-diameter portion 70 .

As shown in FIG. 16 , the small-diameter portion 70 of the push pin 68 is inserted into a through hole 74 provided at a portion near the outer peripheral portion of the unit main body 45 , and is guided by the through hole 74 so as to be guided by the heating roller 14 . The way the axis direction is moved is supported. On the side of the lever portion 41 c opposite to the through hole 74 , a concave cutout portion 75 having an inner diameter larger than the outer diameter of the lock ring 73 is formed.

The stepped portion 72 of the push pin 68 is configured opposite to the first open end of the through hole 74, and the locking ring 73 is configured opposite to the bottom surface of the concave cutout portion 75, which prevents the push pin from being pushed when the auxiliary unit 40 is handled. 68 drops from the unit body 45.

In addition, the push pin 68 is provided at a position opposite to the end surface of the heating roller 14 as shown by a dotted line small circle 71 in FIGS. 17A and 17B , and at a position opposite to the lever portion 41c of the latch 41 as shown in FIG. Position setting push pin 68.

The length of the push pin 68 is such that the small diameter portion 70 protrudes slightly from the outside surface of the unit body 45 where the latches 41 are directed inwardly of each other as shown in FIG. 18B . On the other hand, the length of the push pin 68 is such that the large diameter portion 69 is pressed by the lever portion 41c of the latch 41 and protrudes from the outer peripheral portion of the unit main body 45a when the latches 41 are directed outward from each other as shown in FIG. 18A .

In Fig. 18A, the lever portions 41c of the two latches 41 are directed outwardly from each other. At this time, the shaft portion 41 b of the latch 41 is placed close to the unit main body 45 . Thus, the interval between the clamping piece 43a of the clamper 43 and the inner side surface 45a of the unit main body 45 becomes large, as indicated by L1. As shown in FIG. 19, the interval L1 is slightly larger than the thickness of the absorber 14c.

At this time, the push pin 68 is pressed by the lever portion 41c of the latch 41, which causes the large-diameter portion 69 to protrude slightly from the outer circumferential portion of the unit main body 45a. Similar to the situation of FIG. 18A , FIG. 19 also shows that the lever portions 41 c of the two latches 41 are directed outwardly from each other.

As shown in FIG. 18B , when the lever portions 41 c of the two latches 41 are rotated inwardly of each other, the shaft portion 41 b of the latch 41 moves in a direction away from the unit main body 45 . As the latch 41 moves away from the center, the shaft 42 and the holder 43 also move, which in turn reduces the spacing between the clamping piece 43a of the holder 43 and the side surface 45a of the unit body 45, as indicated by L2. Show. The interval L2 is slightly smaller than the thickness of the absorber 14c. At this time, the lever portion 41c of the latch 41 is offset from the push pin 68, and the large diameter portion 69 is accommodated in the unit main body 45a. In contrast, the small-diameter portion 70 protrudes from the outer side surface of the unit main body 45 . The large-diameter portion 60 is provided to obtain as large a contact area with the heat roller 14 as possible.

The small spacing L2 enables the auxiliary unit 40 to engage with the absorber 14c. Thus, the heat roller 14 and the auxiliary unit 40 are integrally formed with each other, which in turn makes it possible to insert and withdraw the auxiliary unit 40 into and out of the fixing unit 12 . In addition, as shown in FIG. 18A, the large interval L1 makes the auxiliary unit 40 detach from the absorber 14c and makes the large-diameter portion 69 of the push pin 68 protrude from the outer peripheral portion of the unit main body 45a in the direction shown by the arrow to push the heating roller The end surface of 14 is pushed through ring 65 (see Figure 19). Therefore, the auxiliary unit 40 is automatically separated from the heating roller 14 . Note that the ring 65 is made of synthetic resin having heat resistance, which provides good insulation. Note that the large-diameter portion 69 is provided on the side of the end surface of the heating roller 14 opposite to (facing) the push pin 68 so as to increase the opposing area to the end surface of the heating roller 14 .

(Process of replacing the heat roller)

Next, a procedure for replacing the heating roller 14 is described. Similar to the case of the first embodiment, the heat roller 14 is replaced when the heat roller 14 reaches the end of its service life or is to be replaced to meet the needs of the image forming apparatus described above.

FIG. 11 is a step diagram showing a procedure for replacing the heating roller 14 . As shown in FIG. 11 , in step 1, the lamp housing 63 is drawn out from the heating roller 14 by using the protection member 64 . Since this operation was described above with reference to FIG. 5 , a repeated description thereof is omitted here.

Next, in step 2, as shown in FIG. 6 , the guide shaft 30 is inserted in the direction shown by arrow B from the through hole 59 a of the housing 59 . The inner cylinder 59 b of the housing 59 , the absorber 14 d , and the clamping member 48 guide and clamp the guide shaft 30 . When the insertion of the guide shaft 30 reaches a predetermined position, the stopper 31 is inserted in the slit 30 a of the guide shaft 30 , thereby completing the attachment of the guide shaft 30 .

Then, in step 3, the thumb screw 54 is loosened to withdraw the holding member 48 holding the central member 46, the bearing 51, the spring 52, the stopper plate 53, etc. in the direction indicated by the arrow B. At this time, the tip portion of the guide shaft 30 protrudes slightly outward from the outer side surface of the frame 50 . Thus, along with the guidance of the guide shaft 30 , the clamping member 48 can be smoothly withdrawn without colliding with the open end of the frame 50 .

Figure 6 shows the position where the guide shaft 30 is attached and the clamping part 48 is being extracted, while Figure 8 shows the clamping part 48 being extracted.

Next, in Step 4, by gripping the handle 66, the auxiliary unit 40 is inserted from the side of the tip portion of the guide shaft 30 having the inclined surface 30b. At this time, as shown in FIG. 18A , the lever portions 41 of the latch 41 are directed outward from each other. Accordingly, the interval between the inner side surface 45a of the unit main body 45 and the holding piece 43a of the holder 43 is kept large as indicated by L1. In addition, the large-diameter portion 69 of the push pin 68 protrudes from the outer peripheral portion of the unit main body 45 .

17A and 17B are diagrams showing the relationship between the absorber 14c and the holding piece 43a of the holder 43 taken along the plane Y-Y in FIG. 15 . FIG. 17A is a view when the auxiliary unit 40 is inserted into the heating roller 14, and FIG. 17B is a view when the auxiliary unit 40 is attached to the absorber 14c.

As shown in FIGS. 17A and 17B , in the inner peripheral portion of the absorber 14c, two cutouts 67 capable of being inserted into the holding piece 43a of the holder 43 are formed so that the two cutouts 67 are opposed to each other. As shown in FIG. 19 , when the auxiliary unit 40 is inserted into the heating roller 14 , the gripping piece 43 a of the gripper 43 passes through the cutout 67 and is placed on the left side of the absorber 14 c in FIG. 19 . When the large-diameter portion 69 of the push pin 68 comes into contact with the end surface of the heat roller 14 through the ring 65 , the insertion of the auxiliary unit 40 is stopped.

As shown in FIG. 17A, when the auxiliary unit 40 is rotated in the direction indicated by the arrow by gripping the handle 66, the clamping piece 43a of the clamper 43 is rotated from the cutout 67 and faces the absorber 14c as shown in FIG. 17B. Other inner circumference parts. In other words, the other inner peripheral portion of the absorber 14 c is squeezed between the inner side surface 45 a of the unit main body 45 and the holding piece 43 a of the holder 43 . Even if the assist unit 40 is rotated, as shown in FIG. 17B , the arrangement position 71 of the push pin 68 is opposite to (facing) the end surface of the heating roller 14 .

When the lever parts 41c of the latch 41 are rotated inwardly to each other as shown in FIGS. 45, which in turn elastically clamps the inner peripheral portion of the absorber 14c between the clamping piece 43a of the clamper 43 and the inner side surface 45a of the unit main body 45, and makes the small diameter portion 70 of the push pin 68 The end of the unit protrudes from the outer side surface 45b of the unit main body 45 . Therefore, the auxiliary unit 40 is attached to the heating roller 14 through the absorber 14c.

Then, in Step 5 , the heating roller 14 at high temperature is drawn out from the image forming apparatus by gripping the handle 66 of the auxiliary unit 40 . FIG. 15 shows when the heating roller 14 is to be drawn out in the direction shown by arrow B. As shown in FIG. At this time, the inner cylinder 59 b of the housing 59 securely holds the guide shaft 30 , and the inner peripheral surface of the absorber 14 d slides on the outer peripheral surface of the guide shaft 30 . Thus, there is no need to manually grip the portion of the heating roller 14 that is at a high temperature, which enables smooth and safe extraction of the heating roller 14 . Even after the extraction of the heating roller 14, the central member 47 and the clamping member 49 maintain themselves as they are.

Next, in Step 6 , the auxiliary unit 40 is attached to the new heating roller 14 for replacement, and the heating roller 14 is loaded by using the guide shaft 30 . Note that the new heat roller 14 is not shown in the figure, but its basic configuration is the same.

Then, in step 7 , the auxiliary unit 40 is drawn out from the heat roller 14 . In step S8 , the clamping member 48 is attached by using the guide shaft 30 . In step 9 , the brake 31 is disengaged to withdraw the guide shaft 30 . In step 10 , the lamp box 63 covered with the protective member 64 is inserted into the heat roller 14 , and then the pinch member 48 is drawn out from the heat roller 14 , thereby completing the attachment of the lamp box 63 .

Note that the attachment of the new heating roller 14 in step 6 is the reverse operation of the extraction of the heating roller 14 in step 5, and the extraction of the auxiliary unit 40 in step 7 is the attachment of the auxiliary unit 40 in step 4 the opposite operation. At this time, the lever portion 41c of the latch 41 is rotated outward, which in turn causes the large-diameter portion 69 of the push pin 68 to protrude from the outer peripheral portion of the unit main body 45a to press the end surface of the heating roller 14 through the ring 65 . Thus, the auxiliary unit 40 can be easily and quickly separated from the heat roller 14 . The attachment of the clamping part 48 in step 8 is the reverse operation of the extraction of the clamping part 48 in step 3, and the extraction of the guide shaft 30 in step 9 is the attachment of the guide shaft 30 in step 2 and the attachment of the lamp box 63 in step 10 is the reverse operation of the extraction of the lamp box 63 in step 1.

In addition, the structure in the vicinity of the heat roller 14, the attachment/attachment operation of the lamp box 63, and the like are the same as those of the first embodiment.

According to the first and second embodiments, the guide shaft 30 is inserted in the image forming apparatus from the direction indicated by the arrow B shown in FIG. 6 (the back of the image forming apparatus). However, the guide shaft 30 may be inserted in the image forming apparatus from the direction indicated by arrow A (the front side of the image forming apparatus) to fix the guide shaft.

According to the first and second embodiments, as shown in FIGS. 13 and 15, the heat roller 14 and the auxiliary unit 40 are connected to each other by using the absorber 14c. However, in order to connect the heat roller 14 and the auxiliary unit 40 to each other, connection portions (such as concave portions, convex portions, and holes) to be engaged with the auxiliary unit 40 may be provided in the heat roller 14 .

According to the first and second embodiments, the replacement of the heat roller 14 with a heat source is described. However, the embodiment of the present invention can be applied to the replacement of the pressure roller with the heat source.

According to the first and second embodiments, the heating roller 14 is coated with a toner release agent and lubricating oil. However, the embodiment of the present invention is also applicable to a fixing unit (image forming apparatus) that coats the pressure roller 15 or both the heat roller 14 and the pressure roller 15 with a toner release agent and lubricating oil.

According to the second embodiment, the auxiliary unit 40 is separated from the heating roller 14 using the push pin 68 . However, a separation unit having an additional configuration such as a rotary lever whose action point presses the end surface of the heating roller 14 may be used.

(third embodiment)

Next, a third embodiment as another mode of the present invention is described.

As shown in FIGS. 20A to 20F, the support roller member 170 is mainly composed of a support roller 171, a first shaft 172 that rotatably supports the support roller 171, a roller plate 173 that fixes the first shaft 172 to one free end, and a roller plate 173 that is provided on the roller plate 173. The base end of the second shaft 174, and the holder plate 175 rotatably supporting the second shaft 174.

As described below, when the heating roller 14 is replaced, the heating roller 14 at a high temperature of about 200° C. is passed over the support roller 171 . Thus, the backup roller 171 is excellent in heat resistance and is made of the same or the same type of material as the front surface layer 14b so as not to damage the front surface layer 14b of the heat roller 14 (see FIG. 4 ). According to this embodiment, the front surface layer 14b of the heating roller 14 is made of, for example, PTFE (polytetrafluoroethylene) resin, PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) resin, or FEP (tetrafluoroethylene-hexafluoroethylene) resin. Fluoropropylene copolymer) resin made of fluororesin. The backup roller 171 is made of the same or the same type of material (fluororesin in this embodiment) as these materials.

In addition, in order to prevent the front surface of the heating roller 14 from being damaged by the supporting roller 171 when the heating roller 14 passes over the rotating supporting roller 171, the supporting roller 171 is formed into a drum shape so that the front surface of the heating roller 14 is aligned with the front surface of the supporting roller 171. surface point contact.

One side end of the roller plate 173 is folded to integrally form a hook 176 , and a groove portion 177 is formed in the holder plate 175 to fit (engage) with the hook 176 . The width of the groove portion 177 is approximately the same as the plate thickness of the hook 176 . In addition, in the holder plate 175 is formed an elongated hole 178 extending parallel to the groove portion 177 and in which the second shaft 174 is inserted. The roller plate 173 is supported in a manner capable of being vertically moved as described below.

20A and 20B are diagrams showing the support roller member 170 when the heating roller 14 is drawn out from or inserted into the image forming apparatus. FIG. 20A is a side view of the support roller member 170, and FIG. 20B is an end plan view. As shown in FIG. 20A , when a hook 176 provided in the roller plate 173 is inserted into (locked in) a groove portion 177 formed in the clamper plate 175 , the roller plate 173 remains upright. Accordingly, as shown in FIG. 8 , the support roller 171 faces the opening portion 78 of the frame 50 for replacement purposes.

20C and 20D are diagrams showing when the backup roller member 170 is moved from the above-described operating position to the below-described standby position. FIG. 20C is a side view of the support roller member 170, and FIG. 20D is an end plan view. As shown in FIG. 20C , the roller plate 173 is lifted in the direction shown by arrow E to disengage (unlock) the hook 176 from the groove portion 177 . The roller plate 173 is then rotated 180 degrees around the center of the second shaft 174 in the direction indicated by the arrow F. As shown in FIG.

20E and 20F are diagrams showing when the backup roller member 170 is on standby. FIG. 20E is a side view of the support roller member 170 and FIG. 20F is an end plan view with the roller plate 173 suspended from the second shaft 174 . Accordingly, the support roller 171 is in standby at a lower position away from the opening 78 of the frame 50 (see FIG. 6 ) for replacement purposes.

FIG. 21 is a diagram showing the arrangement of the backup roller member 170 with respect to the auxiliary unit 40 . According to this embodiment, two auxiliary roller members 170a and 170b are used. For example, as shown in FIG. 8, for the purpose of replacement, two auxiliary roller members 170a and 170b are provided on the outer side surface of the frame 50 and near the opening portion 78 of the frame 50, so that the handle of the auxiliary unit 40 that is grasped by hand 66 enables the heating roller 14 to be drawn out smoothly.

In particular, two support roller members 170 a and 170 b are provided below the heating roller 14 . Furthermore, as shown in FIG. 21 , assuming that the position of a vertical line 179 passing through the roll center O of the heating roll 14 is defined as 0°, a center line 180 perpendicular to the roll shafts of the support rolls 171 a and 171 b is set to be within ± An angle in the range of 30° to ±60° spans the vertical line 179, preferably in the range of from ±40° to ±50° (45° in this embodiment). The support roller members 170 a and 170 b are arranged symmetrically about a vertical line 179 . With this arrangement, when the heating roller is drawn out by the auxiliary unit 40, the support roller members 170a and 170b stably support the heating roller 14 without interfering with the operation. Thus, an unstable factor that may occur at the withdrawal of the heating roller 14 can be eliminated.

Reference numeral 181 in FIG. 21 denotes an attachment plate on which support roller members 170a and 170b are symmetrically arranged. The support roller members 170 a and 170 b are fixed outside the frame 50 by an attachment plate 181 .

According to this embodiment, two backup roller members 170 are provided below the heating roller 14 . However, approximately one or two backup roller members 170 may also be provided above the heating roller 14 . In this case, in the same manner as the lower backup roller members 170 a and 170 b , it is necessary to dispose the upper backup roller 170 at a position that does not interfere with the extraction of the heating roller 14 by the auxiliary unit 40 . Note that there needs to be a predetermined amount of clearance between the upper support roller member 170 and the heat roller 14 so as not to increase the restraining force with respect to the heat roller 14 .

(Process of replacing the heat roller)

Next, a procedure for replacing the heating roller 14 is described. The heat roller 14 is replaced when the heat roller 14 reaches the end of its service life or is to be replaced to meet the needs of the image forming apparatus described above.

FIG. 22 is a step diagram showing a procedure for replacing the heating roller 14 . As shown in FIG. 22 , in step 1, the lamp housing 63 is drawn out from the heating roller 14 by using the protection member 64 . Since this operation was described above with reference to FIG. 5 , a repeated description thereof is omitted here. The withdrawn lamp box 63 is covered with a rigid protective member 64 . Thus, the lamp box 63 is not inadvertently damaged during its replacement operation.

Next, in step 2, as shown in FIG. 6 , the guide shaft 30 is inserted in the direction shown by arrow B from the through hole 59 a of the housing 59 . The inner cylinder 59 b of the housing 59 , the absorber 14 d , and the clamping member 48 guide and clamp the guide shaft 30 . When the insertion of the guide shaft 30 reaches a predetermined position, the stopper 31 is inserted in the slit 30 a of the guide shaft 30 , thereby completing the attachment of the guide shaft 30 .

Then, in step 3, the thumb screw 54 is loosened to withdraw the holding member 48 holding the central member 46, the bearing 51, the spring 52, the stopper plate 53, etc. in the direction indicated by the arrow B. At this time, the tip portion of the guide shaft 30 protrudes slightly outward from the outer side surface of the frame 50 . Thus, along with the guidance of the guide shaft 30 , the clamping member 48 can be smoothly withdrawn without colliding with the open end of the frame 50 . Note that since the center member 46 is separated from the heat roller 14 when the clamp member 48 is drawn out, the center member 46 and the bearing 51 are brought into contact with the stopper plate 53 by the restoring force of the spring 52 .

At this time, since the support roller 171 of the support roller member 170 is in a standby state (placed in a lower position) as shown in FIG. 6 , no problem occurs in drawing out the clamping member 48 .

Next, in Step 4, by gripping the handle 66, the auxiliary unit 40 is inserted from the side of the tip portion of the guide shaft 30 having the inclined surface 30b. At this time, as shown in FIG. 9A , the lever portions 41 of the latch 41 are directed outward from each other. Accordingly, the interval between the inner side surface 45a of the unit main body 45 and the holding piece 43a of the holder 43 becomes larger, as indicated by L1.

12A and 12B are diagrams showing the relationship between the absorber 14c and the holding piece 43a of the holder 43 seen from the arrow X-X direction in FIG. 7 . FIG. 12A is a diagram showing when the auxiliary unit 40 is inserted into the heating roller 14, and FIG. 12B is a diagram showing when the auxiliary unit 40 is attached to the absorber 14c.

As shown in FIG. 12A, in the inner peripheral portion of the absorber 14c, two cutouts 67 capable of being inserted into the holding piece 43a of the holder 43 are formed so that the two cutouts 67 are opposed to each other. As shown in FIG. 7 , when the auxiliary unit 40 is inserted into the heat roller 14 , the clamping piece 43 a of the clamper 43 passes through the cutout 67 and is placed on the left side of the absorber 14 c in FIG. 7 . When the flange 45c of the unit main body 45 comes into contact with the outer side surface of the frame 50, the insertion of the auxiliary unit 40 is stopped.

When the auxiliary unit 40 is rotated at a predetermined angle by gripping the handle 66, the clamping piece 43a of the clamper 43 is disengaged from the cutout 67 and faces the other inner circumference portion of the clamper 43 as shown in FIG. 12B. When the lever portions 41c of the latch 41 are rotated inwardly with each other as shown in FIG. The inner peripheral portion of the holder 43 is elastically held between the holding piece 43 a of the unit body 45 and the inner side surface 45 a of the unit main body 45 . Therefore, the auxiliary unit 40 is attached to the heating roller 14 through the absorber 14c.

Then, in step 5, the auxiliary roller 171 is moved to its operative position and locked. To perform this operation, the roller plate 173 shown in FIG. 20E is rotated 180 degrees in the direction relative to the arrow F, and the hook 176 is fitted to the groove portion 177 . By this movement, the support roller 171 faces the opening portion 78 of the frame 50 shown in FIG. 8 for replacement purposes.

Then, in Step 6 , the heating roller 14 at high temperature is drawn out from the image forming apparatus by gripping the handle 66 of the auxiliary unit 40 . At this time, the inner cylinder 59b of the casing 59 securely holds the guide shaft 30, and the inner peripheral portion of the absorber 14d slides on the outer peripheral surface of the guide shaft 30, and the portion of the heating roller 14 protruding from the frame 50 is supported by The rollers 171a and 171b are firmly supported. As the heat roller 14 is drawn out, the backup rollers 171a and 171b rotate. FIG. 23 shows the heating roller 14 in a supported state. As shown in FIG. 23, the heat roller 14 is supported at two contact points P by support rollers 171a and 171b. Thus, there is no need to manually grip the portion of the heating roller 14 that is at a high temperature, which enables smooth and safe withdrawal of the heating roller 14 .

Even after the extraction of the heating roller 14, the central member 47 and the clamping member 49 maintain themselves as they are. Fig. 14 shows the heating roller 14 being drawn out.

Next, in Step 7 , the auxiliary unit 40 is attached to a new heating roller 14 (not shown) for replacement, and the heating roller 14 is loaded by using the guide shaft 30 . At this time, the smooth insertion of the heating roller 14 is made possible using the support rollers 171 a and 171 b.

Then, in step 8, the support rollers 171a and 171b are unlocked and moved to their standby positions. This operation is described above with reference to FIGS. 20A to 20F , and thus a repeated description thereof is omitted here.

Then, in Step 9 , the auxiliary unit 40 is drawn out from the heat roller 14 . In step S10 , the clamping member 48 is attached by using the guide shaft 30 . In step 11 , the brake 31 is disengaged to withdraw the guide shaft 30 . In step 12 , the lamp box 63 covered with the protective member 64 is inserted into the heat roller 14 , and then the pinch member 48 is drawn out from the heat roller 14 , thereby completing the attachment of the lamp box 63 .

Note that since the attachment of the new heating roller 14 in step 7 is the reverse operation of the extraction of the heating roller 14 in step 6, the extraction of the auxiliary unit 40 in step 9 is the extraction of the auxiliary unit 40 in step 4. The opposite operation of attaching, the attachment of the clamping part 48 in step 10 is the reverse operation of the extraction of the clamping part 48 in step 3, the extraction of the guide shaft 30 in step 11 is in step 2 The attachment of the guide shaft 30 is the opposite operation, and the attachment of the light box 63 in Step 12 is the opposite operation of the extraction of the light box 63 in Step 1, so their descriptions are omitted here.

According to the third embodiment, when the heating roller 14 is replaced, the heating roller 14 and the auxiliary unit 40 are connected to each other by using the absorber 14c shown in FIG. 13 . However, in order to connect the heating roller 14 and the auxiliary unit 40 to each other, connecting portions (such as concave portions, convex portions, and holes) to be engaged with the auxiliary unit 40 may be provided in the heating roller 14 .

According to a third embodiment, support rollers are used as support members. However, other support members such as having balls that can rotate in eg one direction and having arcuate protrusions that do not rotate may also be used.

According to the third embodiment, the entire backup roller is made of fluororesin. However, the main body of the support rollers, balls or protrusions may be made of a rigid material such as metal and coated with fluororesin on its front surface layer.

According to the third embodiment, replacement of the heating roller 14 is described. However, the embodiment of the present invention can be applied to the replacement of the pressure roller 15 with or without a heat source.

According to the third embodiment, the heat roller 14 is coated with a toner release agent and lubricating oil. However, the embodiment of the present invention is also applicable to a fixing unit (image forming apparatus) that coats the pressure roller 15 or both the heat roller 14 and the pressure roller 15 with a toner release agent and lubricating oil.

Next, effects of the embodiment of the present invention are described. According to an embodiment of the present invention, an auxiliary unit connection portion to which an auxiliary unit that assists the extraction of the heating roller is detachably connected is provided at an end portion in the drawing-out direction of the roller, and the auxiliary unit for drawing out the heating roller is provided. Can be separated from the fixing unit. Thus, the fixing unit can be downsized compared to the fixing unit described in Patent Document 1. FIG. In addition, the auxiliary unit is separated from the fixing unit during normal printing operation. Thus, the auxiliary unit is not heated to a high temperature due to the heat of the fixing unit, which in turn can improve workability and safety when replacing the roller.

According to an embodiment of the present invention, a heat transfer preventing member integrally connected to the heating roller is used as the auxiliary unit connecting portion. Thus, there is no need to provide a roller with a dedicated auxiliary unit connection portion, which in turn solves the problem of complicating the structure of the fixing unit and increasing its size.

According to an embodiment of the present invention, an inner cylinder holding the guide shaft is provided inside the bearing holding member. Thus, when the roller is replaced, the guide shaft is reliably held by the inner cylinder, which in turn enables safe and smooth replacement of the heating roller.

According to an embodiment of the present invention, a locking unit is provided to prevent positional displacement of the guide shaft. Thus, the function of the guide shaft is reliably performed, which in turn enables safe and smooth replacement of the heating roller.

According to an embodiment of the present invention, the guide shaft is held by the heat transfer preventing member. Thus, the posture of the guide shaft is stabilized, which in turn enables safe and smooth replacement of the heating roller.

According to an embodiment of the present invention, an auxiliary tool for replacing a roller has a guide shaft detachably attached to a fixing unit and an auxiliary unit externally installed into an end of the guide shaft to insert and withdraw a heating roller, and the guide shaft and auxiliary unit can be separated from the fixing unit. Thus, the fixing unit can be downsized compared to the fixing unit described in Patent Document 1. FIG. The guide shaft and auxiliary unit are separated from the fixing unit during normal printing operation. Thus, the guide shaft and the auxiliary unit are not heated to a high temperature due to the heat of the fixing unit, which in turn enables easy and safe replacement of the heating roller.

According to an embodiment of the present invention, even a roll that is at a high temperature due to its heat source can be easily and safely replaced.

According to the embodiments of the present invention, even a roller that is difficult to handle due to its coated toner release agent or lubricating oil can be easily and safely replaced.

According to an embodiment of the present invention, the auxiliary unit has a pinching unit that pinches the auxiliary unit connection portion of the heating roller, and an operation unit that performs a pinching operation of the pinching unit. Thus, the auxiliary unit is reliably connected to the roller.

According to an embodiment of the present invention, the auxiliary unit has a separating unit that presses the end surface of the roller to separate the auxiliary unit from the heating roller. Thus, the auxiliary unit is quickly and reliably detached from the heating roller, which in turn enables a quick replacement operation of the roller.

According to an embodiment of the present invention, a plurality of separation units are arranged at regular intervals on the outer circumferential portion of the auxiliary unit. Thus, the auxiliary unit is separated from the heat roller in an overall well-balanced manner.

According to an embodiment of the present invention, each separation unit has a push pin supported by the auxiliary unit in a manner capable of being moved in the axial direction of the roller. When the end of the push pin protruding from the auxiliary unit is pressed, the push pin presses the end surface of the heating roller to separate the auxiliary unit from the heating roller. Thus, the configuration of the separating unit is simple, and the structure of the auxiliary unit does not become complicated.

According to an embodiment of the present invention, the operation unit that performs the clamping operation of the clamping unit for the auxiliary unit connection portion of the clamping roller presses the push pin. Thus, when the clamping of the auxiliary unit connecting portion by the clamping unit is canceled, the auxiliary unit is also separated from the roller by the push pin. In addition, a guide shaft and an auxiliary unit are used in combination, which in turn makes possible a smooth and safe replacement operation of the heating roller.

According to an embodiment of the invention, a protective member is used. Thus, collective replacement of the lamps is smoothly performed, and damage to the lamps caused during the replacement of the lamps can be avoided. As a result, high security is obtained.

According to an embodiment of the present invention, the protective member is made of a paper tube. Thus, the protection member is easy to obtain, and the cost of the protection member can be reduced.

According to an embodiment of the present invention, the separating unit can quickly and reliably separate the auxiliary unit from the heating roller. Thus, the replacement operation of the rollers can become more efficient.

The present invention is not limited to the particularly disclosed embodiments, and changes and modifications can be made without departing from the scope of the invention.

Claims (9)

1. a fixation unit for fixing ink powder image, comprising:

Warm-up mill;

Pressure roll, can carry out pressure with described warm-up mill and contact, and one in described warm-up mill and described pressure roll can be inserted by the direction of principal axis along roller and extract out;

For the opening replaced, be formed in the framework relative with the roller that can be inserted into and extract out; And

Support component, near the outside being arranged on described framework and the described opening for replacing, to support the roller that will be drawn out of and insert,

Described support component comprise backing roll, rotatably supported roller the first axle, have free end roller plate, be arranged on the second axle of the cardinal extremity of roller plate and rotatably support the clamper plate of the second axle, wherein, described first axle is fixed on the free end of described roller plate.

2. the fixation unit of fixing ink powder image according to claim 1, is characterized in that,

At least front surface portion of the described support component of contact roller is made up of the material with slip attribute.

3. the fixation unit of fixing ink powder image according to claim 2, is characterized in that,

Described roller has the front surface layer be made up of fluororesin, and the part contacting the described support component of roller is made up of fluororesin.

4. the fixation unit of fixing ink powder image according to any one of claim 1 to 3, is characterized in that,

Roller is by supporting with the point cantact of described support component.

5. the fixation unit of fixing ink powder image according to any one of claim 1 to 3, is characterized in that,

Described support component can the operating position of backing roll and away from described operating position spare space between back and forth movement, the fixation unit of described fixing ink powder image also comprises:

Lock cell, remains on described operating position by described support component.

6. the fixation unit of fixing ink powder image according to any one of claim 1 to 3, is characterized in that,

When position on the perpendicular line of the roller central authorities through roller is restricted to 0 °, at least two support components are arranged in the scope of ± 30 ° to ± 60 ° with the low portion of backing roll.

7. the fixation unit of fixing ink powder image according to claim 6, is characterized in that,

Described at least two support components are arranged symmetrically about the central authorities of described perpendicular line.

8. the fixation unit of fixing ink powder image according to claim 6, is characterized in that,

One in described support component is also arranged on the upper part of the roller being inserted into and extracting out, to have gap between the described upper part and described support component of roller.

9. the fixation unit of fixing ink powder image according to claim 7, is characterized in that,

One in described support component is also arranged on the upper part of the roller being inserted into and extracting out, to have gap between the described upper part and described support component of roller.