JP4715416B2 - Fixing device - Google Patents

Description

  The present invention relates to a heat fixing type fixing device used for an image forming apparatus such as a printer, a copying machine, or a multi-function machine that forms an image made of toner on a sheet-like material such as paper using an electrophotographic method or the like. In particular, the present invention relates to an improvement of a fixing device in which measures are taken to suppress the heat generated by a heating rotator or the like from being released to the outside of the device.

  In recent years, in the image forming apparatus as described above, there is an increasing demand for an increase in image forming speed, miniaturization of the apparatus, and energy saving (energy saving).

  For this reason, a thermal fixing type fixing device for fixing an unfixed toner image formed by an image forming device to a sheet-like material such as paper is most likely to require high-temperature heating during the image forming process. In order to consume electric power energy, it is said that energy saving (low power consumption) technology that leads to a reduction in environmental load is particularly necessary.

  Further, in such a fixing device, since the fixing process is performed, not only when fixing is performed but also in a standby state, a predetermined heating state is maintained. In order to reduce the size of the fixing device, a cleaning device, a toner cartridge, and the like are arranged in the vicinity of the fixing device. There may be a problem that the toner and the like are adversely affected by heat (such as a phenomenon of fusing and aggregation).

  Conventionally, in order to solve such problems, as shown below, a heat reflecting plate, a heat insulating material, etc. are arranged around a heating rotary body such as a heating roll to suppress heat dissipation from the heating source and consume. A fixing device that makes it possible to save energy has been proposed.

  For example, there is a fixing device in which heat reflecting means for reflecting heat radiated from a heating roller toward the roller surface is disposed in a non-contact state at a position surrounding the outer peripheral surface of the roller (Patent Document 1). Specific examples of the heat reflecting means include a reflector made of metal shaped so as to surround the outer peripheral surface of the heating roller, or a curved surface portion along the outer peripheral surface of the roller surrounding the heating roller. The thing which gave metal plating is illustrated.

  In addition, a shielding plate surrounding the heating roller, a heat insulating material to be attached to the shielding plate, a cap for closing the side surface of the heating roller, and a frame provided with a heat insulating material for housing the heating roller and the shielding plate are provided. There is a fixing device (Patent Document 2).

  However, since all of the fixing devices according to the conventional proposals are in an open state between the heat reflecting plate or the shielding plate and the frame, heat enters the gap between the heat reflecting plate and the frame and removes the frame. There is a risk that heat will be generated and heat dissipation from the frame will occur. For this reason, it can be said that there is still room for improvement from the viewpoint of achieving the object of suppressing heat dissipation from the heat source.

  Therefore, conventionally, for the purpose of suppressing heat release from the casing (exterior cover), the recording paper conveyed in a substantially vertical direction from the bottom to the top in the casing passes between the heating roller and the pressure roller. The fixing device is provided with an opening / closing plate that opens when the recording paper passes through the upper opening and closes when the recording paper does not pass through the fixing device that is discharged through the upper opening of the casing after fixing. It has been proposed (Patent Document 3).

  In addition, there is a fixing device that has a structure in which the fixing rotation member is covered with a heat insulating material, the heat insulating material is further covered with a fixing device cover, and the cover can be opened to a position where a paper jam (jam) processing is performed. It has been proposed (Patent Document 4). In this fixing device, an air gap is formed between the fixing device cover and the heat insulating material when the cover is closed.

JP-A-9-101700 Japanese Patent Laid-Open No. 6-59596 JP 2003-241551 A JP-A-5-173440

  However, the fixing device proposed in Patent Documents 3 and 4 has the following problems.

  That is, in the fixing device proposed in Patent Document 3, heat release from the casing upper opening during non-sheet passing can be prevented by the opening / closing plate, but around the heating roller or the like arranged in the casing. Since heat reflection or heat shielding is not performed, the casing itself is heated, and there is a possibility that heat radiation from the heated casing occurs. In addition to this, when an opening / closing plate that only closes the upper opening of the casing is provided, it is difficult to perform jam processing work because the upper opening is narrow, and the jammed paper may not be removed. is there.

  Further, the fixing device proposed in Patent Document 4 has a problem that heat is likely to leak from a gap existing in a hinge portion or the like for forming a fixing device cover opening / closing structure. In addition, since there is a gap between the fixing device cover and the heat insulating material when the fuser cover is closed, heat enters the gap and heats the cover, which may cause heat dissipation from the cover.

  The present invention has been made in view of the above-described problems, and can reduce power consumption by accurately suppressing heat dissipation from a heating source such as a rotating body for heating and thus heat dissipation from an exterior cover. At the same time, it is an object of the present invention to provide a fixing device capable of ensuring good operability of the jam handling operation.

  The fixing device according to the present invention includes a heating rotator and a pressing rotator that are pressed against each other so as to form a fixing nip portion through which a sheet-like material carrying an unfixed toner image passes, and the heating rotator and pressurizing member. A state of surrounding each outer surface of the rotating body so as to be closely enclosed within a range excluding the passage part of the sheet-like material, and a state surrounding the outer side of the heat reflecting plate with a space therebetween And an outer cover made of a synthetic resin arranged in the above, and the end of the outer cover facing the passage part of the sheet-like material is in contact with the heat reflecting plate except that it is replaced with another component. And is formed as an open / close cover that opens and closes so that a part of the passage of the sheet-like material is widened, and when the open / close cover is closed. Its tip is the heat reflection And it is characterized in that it is formed in the form in contact with.

  Here, the end of the exterior cover is formed so as to be in contact with the heat reflecting plate. For example, the end of the outer cover is bent toward the side where the heat reflecting plate is present so as to be in contact with the heat reflecting plate. Is to form a special part. However, existing components (for example, a peeling plate for peeling paper) are arranged in a positional relationship so as to be able to come into contact with both the end portion of the exterior cover and the heat reflecting plate at a part facing the passage part of the sheet-like material If there is a guide plate or the like for guiding the paper, a part of the components may be used instead of the exterior cover.

  A part of the exterior cover formed as the open / close cover may be formed so that the tip of the external cover comes into contact with the heat reflecting plate when the open / close cover is closed. The shape and the like can be arbitrarily set.

  The heat reflecting plate is not particularly limited as long as it can reflect high heat (radiant heat) generated from a heating source such as a heating rotator to the rotator side. Consists of composite materials with other materials. In addition, the synthetic resin constituting the exterior cover is preferably heat-resistant or imparted, and more preferably exhibits low thermal conductivity. Further, the sheet-like material may be any material that can carry out normal fixing processing by carrying a toner image and passing through the fixing nip portion.

  The fixing device may be formed such that when the opening / closing cover is closed, the opening / closing cover and the other exterior cover portion overlap each other.

  When configured in this way, it is possible to reduce heat radiation through the gaps such as the opening / closing portion of the opening / closing cover and the opening / closing mechanism portion thereof.

  In each of the fixing devices, an elastic member that fills the gap may be attached to a gap that exists between the opening / closing cover and the other exterior cover portion when the opening / closing cover is closed. As the elastic member, one that does not hinder the opening / closing operation of the opening / closing cover and is easy to maintain airtightness when the cover is closed is preferable. For example, an elastic foam such as a heat-resistant sponge, other cushioning materials, etc. Is used.

  When configured in this way, it is possible to reduce heat radiation through the gaps such as the opening / closing portion of the opening / closing cover and the opening / closing mechanism portion thereof. In particular, when combined with the formation of the above-described overlapping state, the heat radiation can be reduced more reliably.

  In each of the fixing devices, a low thermal conductivity member may be attached to the outer surface of the heat reflecting plate. As the low thermal conductive member, any member can be used as long as it can effectively suppress heat generated when the heat reflecting plate is heated to be conducted to the outside and dissipated. For example, a heat resistant resin layer, heat resistant And flocking members.

  When comprised in this way, it will become suppressed that the heat | fever emitted when a heat | fever reflecting plate is heated is conducted to the outer side, and is thermally radiated. As a result, it is possible to suppress heating of the exterior cover by the heat dissipation. Further, even when the heat reflection plate is present in the opened portion of the opening / closing cover and the heat reflection plate is accidentally touched, safety is ensured.

  Further, in each of the fixing devices, it is preferable that a part of the heat reflecting plate is formed as an opening / closing plate that opens and closes so that the space of the passage portion of the sheet-like material is expanded.

  In such a configuration, by opening the opening / closing plate, the space of the sheet-like material passage portion, particularly the space near the fixing nip portion, can be expanded, so that the removal operation of the jammed sheet-like material is more It becomes easier to do. Further, if the opening / closing plate is closed, the effect of heat reflection is obtained, and the effect of reducing heat dissipation is obtained.

  Further, in each of the fixing devices, when the sheet-like material passes through the passage cover through the exterior cover or the opening / closing cover facing the passage portion of the sheet-like material and the sheet-like material does not pass therethrough. A shutter member that closes so as to close the opening of the passage portion may be provided. In particular, in the fixing device in which the sheet-like material discharged from the fixing nip portion is discharged upward, the shutter member is attached to at least the exterior cover or the opening / closing cover on the discharge side passage portion side. It is preferable to provide it.

  When comprised in this way, the heat radiation from the opening part of the passage part of a sheet-like material, especially the heat radiation at the time of the non-passage of a sheet-like material can be prevented effectively.

  According to the fixing device of the present invention, the end portion of the exterior cover that faces the passage portion of the sheet-like material is formed in a form that comes into contact with the heat reflecting plate except that it is replaced with other components. There is no possibility of heat entering through the gap between the heat reflecting plate and the exterior cover existing in the part and the like to heat the exterior cover. In addition, since a highly airtight space layer (a space where there is almost no air inflow or outflow) exists between the heat reflecting plate and the exterior cover, it functions as an air heat insulating layer. The heat generated by heating becomes difficult to be transmitted to the exterior cover, and it becomes difficult to heat the exterior cover. As a result, when the exterior cover is heated, heat radiation from the exterior cover is accurately suppressed. From the standpoint of energy saving, this heat dissipation suppression effect is particularly useful during standby time, which is not only effective during the fixing operation of the fixing device but also occupies much more time than the fixing operation time. It is.

  In addition, the exterior cover is formed as an open / close cover that opens and closes so that the space of the sheet passing portion is widened, and when the open / close cover is closed, its tip is a heat reflecting plate. In addition to obtaining the above-mentioned effect of suppressing heat dissipation, even if the sheet-like material is clogged when passing through the fixing device, the sheet-like material can be passed by opening the opening / closing cover. Since the space of the part is expanded, it is possible to easily remove the jammed sheet-like material. In addition, when the opening / closing cover is closed, the tip portion thereof contacts the heat reflecting plate, so that the above-described effect of suppressing heat dissipation is maintained.

  Therefore, with this fixing device, heat dissipation from the heating source such as a rotating body for heating, and hence heat dissipation from the exterior cover, can be accurately suppressed to reduce power consumption, and good operability of the jam handling work can be ensured. You can also Further, even when a heat-sensitive component is disposed in the vicinity of the fixing device, it is possible to avoid inadvertently heating it.

[Embodiment 1]
1 and 2 show the main part of the fixing device according to Embodiment 1 of the present invention. FIG. 1 is a longitudinal sectional view of the fixing device, and FIG. 2 is a schematic explanatory view when viewed from above. is there.

  The fixing device 1A is installed so as to form a heating roll 2 installed so as to be rotationally driven, and a fixing nip portion N that is pressed against the heating roll 2 and allows the paper P carrying the unfixed toner image T to pass therethrough. The pressure belt 3 and the peripheral surfaces of the heating roll 2 and the pressure belt 3 are surrounded by a predetermined interval (L) while excluding the passage portion (E) of the paper P. The heat reflecting plate 4 arranged, the outer cover 5 arranged so as to surround the outside of the heat reflecting plate 4 with a predetermined interval, the heating roll 2 and the pressure belt 3 are supported and the outer cover. 4 is provided with a pair of side support frames 6A and 6B to which 4 is connected, and a peeling plate 7 for peeling the paper P after fixing from the heating roll 2. Reference numeral 8 in FIG. 1 and the like is a space layer as an air elastic layer formed between the heat reflecting plate 4 and the exterior cover 5.

  The heating roll 2 is made of a core metal formed in a relatively thin cylindrical shape with a metal such as aluminum or stainless steel, and a releasable material such as tetrafluoroethylene or PFA formed on the outer peripheral surface of the core metal. It consists of a release layer. A plurality of halogen heaters 23 as heating sources are installed inside the heating roll 2 (core metal). The heating roll 2 is heated to a predetermined temperature (fixing temperature, standby temperature, etc.) by controlling the energization state to the halogen heater 23 based on detection information from a temperature sensor (not shown) that measures the roll surface temperature. It is comprised so that it may be kept in the state kept. Further, the heating roll 2 receives rotational power from a rotational drive device (not shown) by a driven gear 25 and is rotationally driven in a direction indicated by an arrow at a predetermined speed.

  The pressure belt 3 includes an endless belt 31 having a structure in which a release layer such as PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) is laminated on a belt base material of a heat-resistant film made of polyimide or the like, A pressure support pad structure 32 that is disposed on the inner peripheral surface side of the endless belt 31 and supports the belt 31 so as to be in pressure contact with the surface of the heating roll 2 and to be driven to rotate as the heating roll 2 rotates. It is configured. The pressure support pad structure 32 is in contact with the inner peripheral surface of the endless belt 31 and contributes to the formation of the fixing nip N. A holder portion with a pressurizing mechanism for pressing, a belt guide portion for guiding the both ends of the holder portion while regulating the position of the end portion of the belt 31, and the like.

  In this example, as the heating roll 2, a 1.6 mm thick elastic layer made of silicone rubber or the like is formed on a core metal having an outer diameter of 26 mmφ and a wall thickness of 1.6 mm, and a thickness made of PFA is further formed on the elastic layer. What formed the 30 micrometer release layer is used. The heating roll 2 is heated by a 1.1 kW halogen heater 23 so that the roll surface temperature during fixing is maintained at 160 ° C. Further, as the pressure belt 3, an endless belt 31 formed by laminating a release layer of PFA having a thickness of 30 μm on the surface of a polyimide film belt having a belt diameter of 30 mm, an axial width of 344 mm, and a thickness of 75 μm was used.

  In the fixing device 1, the heating roll 2 and the pressure belt 3 are installed in a horizontal state (horizontal placement), and the fixing nip N is formed by pressing in this state. For this reason, the conveyance path of the paper P at the time of fixing is conveyed so as to rise from the lower side of the fixing device 1 toward the fixing nip N, and is also conveyed upward after passing through the fixing nip N. This is a route that travels in a substantially vertical direction.

  The heat reflecting plate 4 is a plate member made of metal such as stainless steel, and a rectangular flat plate having a length substantially corresponding to the axial length of the heating roll 2 and the pressure belt 3 is added to the heating roll 2 and the heating plate 2. The pressure belt 3 is used in a form (curved shape) bent into a curved surface shape (a U-shaped cross section) substantially along each outer peripheral surface (cylindrical side surface) of the pressure belt 3.

  The heat reflecting plate 4A arranged on the heating roll 2 side was arranged in a state surrounding the roll peripheral surface (for the right half circumference in FIG. 1) with an interval La. Further, the heat reflecting plate 4B arranged on the pressure belt 3 side is arranged in a state of surrounding the belt outer peripheral surface (the left half circumference in FIG. 1) with an interval Lb. Then, a passage area Ein on the entrance side that passes when the sheet P before fixing is introduced into the fixing nip N, and a passage area Eout on the exit side that passes when the sheet P after fixing is discharged from the fixing nip N. , A space through which the paper P can pass is secured without the heat reflecting plate 4 being disposed.

  In this example, a heat reflecting plate 4 (A, B) made of a galvanized steel plate having a thickness of 0.5 mm and an axial length of 320 mm was used. In addition, the distance La from the heating roll 2 of the heat reflecting plate 4A is set to about 2 mm, and the distance Lb from the pressure belt of the heat reflecting plate 4B is also set to about 2 mm.

  The exterior cover 5 is molded by using, for example, a heat-resistant synthetic resin, and has a shape that can surround the outside of the heat reflecting plate 4 with a predetermined interval. In this example, a set of exterior covers 5A and 5B each having a substantially box shape disposed on the heating roll 2 side and the pressure belt 3 side, respectively. In this example, the exterior cover 5 (A, B) is formed of heat resistant PET (polyethylene terephthalate). The length of the exterior cover 5 (A, B) in the axial direction was 380 mm.

  The pair of side support frames 6A and 6B are arranged facing each other at both ends of the heating roll 2 and the pressure belt 3, and support the heating roller 2 so as to be rotatable and The pressure support pad structure 32 is supported. Further, the exterior cover 5 (A, B) is fixedly attached to the side support frames 6A, 6B so as to connect both the frames 6 (A, B) along the rotation axis direction of the heating roll 2. Yes. In addition, although it is preferable to attach the heat | fever reflecting plate 4 to the exterior cover 5, you may make it attach to these support frames 6A and 6B. In this example, the support frames 6A and 6B are formed of a galvanized steel plate.

  In the fixing device 1A, the end of the exterior cover 5 (A, B) facing the paper passage area (Ein, Eout) is basically in contact with the heat reflecting plate 4 (A, B). It is formed to become.

  In this example, as shown in FIG. 1 and the like, an end portion (hereinafter also referred to as an “axial end portion”) 51 along the axial direction of the heating roll 2 and the pressure belt 3 of the exterior cover 5 (A, B). , 52 are in contact with end portions (hereinafter also referred to as “axial end portions”) 41, 42 of the heat reflecting plate 4 (A, B) along the axial direction of the heating roll 2 and the pressure belt 3. It is formed as bent end portions 51a and 52a having such a shape that it is bent into two.

  In this example, the axial end 51 on the paper exit side passage region Eout side of the exterior cover 5A disposed on the heating roll 2 side is between the end 51 and the axial end 41 of the heat reflecting plate 4A. Since the peeling plate 7 is present in a state of closing, the peeling plate 7 is used as a substitute for the bent end 51a of the exterior cover. Further, in the axial end 51 on the paper exit side passage area Eout side of the exterior cover 5B arranged on the pressure belt 3 side, the front end of the opening / closing cover described later functions as a bent end 51a of the exterior cover. Become.

  Further, in the fixing device 1A, as shown in FIG. 1 and the like, an upper part of the exterior cover 5B is formed as an opening / closing cover 55 that opens and closes so that the space of the paper exit side passage area Eout is widened. ing.

  In this example, the open / close cover 55 has an L-shaped cross section in which the front end portion 55a is bent in a direction in contact with the axial end portion 41 of the heat reflecting plate 4B, and the rear end side thereof is a normal one. The exterior cover 5B is connected to the opening / closing hinge mechanism 56 so as to be opened and closed.

  In addition, in the fixing device 1a, as shown in FIG. 1 and the like, a low thermal conductive resin layer 9 is formed on the outer surface of the heat reflecting plate 4 (A, B). In this example, a low heat conductive resin layer 9 coated with ETFE (ethylene-tetrafluoroethylene) which is a heat resistant resin (thermal conductivity: 0.24 W / mK) was applied.

  Next, the operation of the fixing device 1A will be described.

  At the time of fixing, the heating roll 2 is heated to a predetermined surface temperature (fixing temperature) by the halogen heater 23 and is rotated in the direction of the arrow. At this time, the pressure belt 3 is driven to rotate while forming the fixing nip portion N with the heating roll 2.

  The sheet P on which the unfixed toner image T formed in the image forming unit (not shown) is transferred to the fixing device 1 in such a fixable state as shown in FIG. , And is conveyed so as to be introduced into the fixing nip N. The unfixed toner image T is melted and fixed on the paper P by being heated and pressurized through the fixing nip N. The sheet P after the fixing process passes through the exit area Eout and is discharged out of the fixing device.

  Further, the fixing device 1 stands by in a state where the heating roll 2 is heated to a predetermined standby temperature until the next fixing operation is started even when the paper P to be fixed is not introduced and passed.

  Also in the fixing device 1, heat is mainly released from the heating roll 2 during fixing or standby, but the heat is reflected by the heat reflecting plates 4 (A, B) arranged around the heat roller 2. It is difficult to escape to the outside and the loss of heat energy is reduced.

  Further, the outer cover 5 (A, B) has bent end portions 51a, 52a (including the substitute peeling plate 7) which are axial end portions thereof, and the axial end portions 41, 41 of the heat reflecting plate (A, B). 42 in contact with the support frame 6A, 6B, etc. The end portions of the outer cover 5 (A, B) and the heat reflecting plate (A, B) in the circumferential direction of the heating roll 2 and the like are also in contact with the support frames 6A, 6B. It is in a state (FIGS. 1 and 2). For this reason, the air layers 8A and 8B between the heat reflecting plates (A and B) and the exterior cover 5 (A and B) are almost sealed, and air (including heat) flows in and out. There is almost no function and functions as an excellent air insulation layer. For this reason, the heat of the heated heat reflecting plates (A, B) is hardly transmitted to the exterior cover 5 (A, B) or the like, and as a result, the exterior cover 5 (A, B) is not easily heated.

  Moreover, since the low thermal conductive resin layer 9 is formed on the outer surface of the heat reflecting plate 4 (A, B), the heat of the heat reflecting plate (A, B) heated by this is also applied to the exterior cover 5 (A , B).

  For this reason, heat dissipation from the outer cover 5 (A, B) is prevented. As a result, the heat energy loss of the heating roll 2 (the halogen heater 23) can be greatly suppressed, so that power consumption is reduced.

  Further, in the fixing device 1A, when the paper P is jammed in the fixing device during the fixing operation, the opening / closing cover portion 55 at the top of the exterior cover 5B can be opened as shown in FIG. As a result, the space on the exit side passage area Eout of the paper near the upper part of the exterior cover 5B is expanded, and it is easy to remove the paper P jammed in the passage area Eout.

  When the open / close cover portion 55 is closed, the tip end portion 55a is in contact with the axial end portion 41 of the heat reflecting plate (A, B), so that the air layer 8B is also sealed. Kept. Further, when the opening / closing cover part 55 is opened, even if the heat reflecting plate 4B exposed below is accidentally touched, the low thermal conductive resin layer 9 is formed on the outer surface of the heat reflecting plate 4B. Therefore, safety is ensured.

[Embodiment 2]
FIG. 4 shows (part of) a main part of the fixing device according to Embodiment 2 of the present invention.

  The fixing device 1B has the same configuration as the fixing device 1A according to the first embodiment except that the periphery of the hinge mechanism portion of the opening / closing cover 55 is modified and changed. For this reason, in FIG. 4 and the like, the same reference numerals are given to the portions common to the fixing device 1A according to the first embodiment, and the description of the common components is omitted below. (The same applies to the following embodiments).

  That is, in this example, as shown in FIGS. 4 and 5, when the opening / closing cover 55 is closed, the opening / closing cover 55 (portion on the hinge mechanism portion 56 side) and the other fixed-side exterior cover portion 53 are predetermined. It is formed so that it will be in the state which overlaps only the area W of. In addition, a gap (including a gap existing on the hinge mechanism 56 side) existing between the opening / closing cover 55 and the other fixed-side exterior cover portion 53 in the overlapped state is filled in to fill the gap. The sponge-like urethane 10 is attached to the outer surface side of the fixed-side exterior cover portion 53.

  In such a fixing device 1B, as in the case of the fixing device 1A according to the first embodiment, the heat radiation from the exterior cover 5 or the like as described above can be reduced, and the jammed paper can be satisfactorily removed. In addition to the effect of ensuring the operability, the following effects are further obtained.

  This is because when the opening / closing cover 55 is closed by forming a state where the predetermined section W is overlapped as described above, heat is generated in a gap existing in the opening / closing portion of the opening / closing cover 55, the hinge mechanism portion 56, and the like. Is difficult to reach directly, and heat dissipation through the gap is reduced. In addition, since the sponge-like urethane 10 is attached, the gap existing near the hinge mechanism portion 56 of the opening / closing cover 55 can be reliably closed by the urethane 10, and this also makes the heat radiation through the gap even more reliable. Reduced to

  Therefore, according to the fixing device 1B, compared to the fixing device 1A according to the first embodiment, the heat energy loss of the heating roll 2 (the halogen heater 23) can be more accurately suppressed, and the power consumption is also large. Reduced.

[Embodiment 3]
FIG. 6 shows (part of) a main part of the fixing device according to the third embodiment of the present invention.

  This fixing device 1C has the same configuration as that of the fixing device 1B according to the second embodiment except that an opening / closing plate is formed on a part of the heat reflecting plate 4 and an opening / closing shutter is additionally provided. .

  That is, as shown in FIG. 6 or the like, as an opening / closing plate 45 that opens and closes so that the space of the exit side passage area Eout of the sheet is widened at the upper part of the heat reflecting plate 4B arranged on the pressure belt 3 side. Forming. In this example, the opening / closing plate 45 cuts and separates a predetermined region of the axial end portion 41 of the heat reflecting plate 4B, and connects it to the other fixed side heat reflecting plate 4B portion by an opening / closing hinge mechanism 46 to open and close the opening / closing plate 45. It is formed so that it can operate.

  Also, as shown in FIGS. 6 to 8, it opens to the upper axial end 51 of the exterior cover 5B facing the outlet side passage area Eout of the paper P when the paper P passes through the outlet side passage area Eout. A shutter member 12 is provided that closes to close the opening of the exit side passage area Eout when the paper P does not pass.

  In this example, a film shutter having a thickness of 0.5 mm made of heat-resistant PET is provided on the front end side of the opening / closing cover 55 corresponding to the upper axial end 51 of the exterior cover 5B as the shutter member 12 via the opening / closing hinge mechanism 13. It can be opened and closed. When there is a sheet P that is discharged from the fixing nip N and passes through the exit-side passage area Eout, the shutter member 12 causes the opening / closing hinge mechanism 13 to move depending on the strength of the waist (rigidity) of the sheet P. It swings as a fulcrum and automatically opens (FIG. 7). In other cases, its tip is in contact with the peeling plate 7 and the like (FIG. 6). In addition, you may comprise this sitter member 12 so that it may open and close using the motive power by drive devices, such as a solenoid.

  In such a fixing device 1C, in the same manner as in the case of the fixing device 1B according to the second embodiment (including the fixing device 1A), the exterior is added in addition to the presence of the overlap portion and the presence of the urethane material as described above. In addition to the effect of accurately reducing the heat radiation from the cover 5 and the like, the effect of ensuring the good operability of removing the jammed paper is obtained, and the following effects are further obtained.

  First, by providing the sitter member 12 as described above, when the paper P does not pass, the opening portion of the paper exit side passage area Eout is blocked by the sitter member 12, so that the paper P does not particularly pass. In some cases, it is possible to effectively prevent heat radiation from the opening portion of the paper exit side passage area Eout.

  When the paper P is jammed, as shown in FIG. 8, in addition to opening the opening / closing cover 55 on the exterior cover side, the opening / closing plate 45 on the heat reflecting plate side can be opened. As a result, the space of the paper exit side passage area Eout opens the opening / closing plate 45 as compared with the case where only the opening / closing cover 55 is provided as in the first and second embodiments. As a result, the paper P is more widely opened, and the operation of removing the paper P jammed in the passage area Eout is further facilitated.

<Performance test>
Hereinafter, performance test results regarding the power consumption reduction effect of the fixing devices 1A, 1B, and 1C according to the first to third embodiments will be described.

  In the test, the power consumption per hour during standby of each fixing device 1A, 1B, 1C was measured. The test condition is that the consumption when the standby heating for maintaining the power heating roll 2 at a temperature of 160 ° C. for 1 hour is performed after 1 hour has passed since the power of the fixing device is turned on (the start of energization to the halogen heater 23). The power was measured with a power meter.

  For comparison, a comparative fixing device as shown in FIG. 10 was prepared and the same test was performed (comparative example). The comparative fixing device is different only in that the fixing device 1A (FIG. 1) according to the first embodiment is omitted by removing the heat reflecting plates 4A and 4B (including the low thermal conductive resin layer 9). Other than that, it has the same configuration.

  The above test results are also shown in FIG.

  As is clear from the result of FIG. 9, when compared with the result of the power consumption of the comparative example, the fixing device 1A according to the first embodiment can obtain the effect of reducing the power consumption, and the fixing device 1A has the overlap structure described above. In the case of the fixing device 1B according to the second embodiment in which the elastic member (urethane material) is added, the power consumption reduction effect is further improved. Then, it can be seen that when the sitter member is provided as in the fixing device 1C according to the third embodiment, the effect of reducing the power consumption when the sheet does not pass is greatly improved.

[Other embodiments]
In the second embodiment, the case where both the overlap structure and the installation of the urethane member are employed has been exemplified, but only one of them may be employed. Even in such a case, substantially the same effect (an effect of suppressing heat dissipation and an effect of reducing power consumption thereby) can be obtained.

  Further, the shutter member 12 can be configured to be provided on the fixed exterior cover 5 instead of being provided on the opening / closing cover 55. An elastic member such as glass wool can be installed in the space layer 8 as necessary.

  In addition, with respect to the fixing device, the heating roll 2 and the pressure belt 3 may be arranged vertically instead of being horizontally arranged as illustrated in the first to third embodiments. it can. Further, for example, a pressure roll can be applied instead of the pressure belt 3.

FIG. 2 is a schematic cross-sectional view illustrating a main part of the fixing device according to the first embodiment. FIG. 2 is a schematic explanatory diagram illustrating a state when the fixing device of FIG. 1 is viewed from above. FIG. 2 is a schematic cross-sectional view showing a state when an opening / closing cover in the fixing device of FIG. 1 is opened. FIG. 4 is a schematic cross-sectional view illustrating a main part of a fixing device according to a second embodiment. FIG. 5 is a schematic cross-sectional view showing a state when an opening / closing cover in the fixing device of FIG. 4 is opened. 5 is a schematic cross-sectional view showing a main part of a fixing device according to Embodiment 3. FIG. FIG. 7 is a schematic cross-sectional view showing a state when a sheet passes in the fixing device of FIG. 6. FIG. 7 is a schematic cross-sectional view showing a state when an opening / closing cover and an opening / closing plate in the fixing device of FIG. 6 are opened. It is a graph which shows the result of a performance test. FIG. 3 is a schematic cross-sectional view showing a main part of a comparative fixing device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1A, 1B, 1C ... Fixing device, 2 ... Heating roll (rotating body for heating), 3 ... Pressure belt (rotating body for pressing), 4 ... Heat reflecting plate, 5 ... Exterior cover, 7 ... Release plate (Other Component parts), 9 ... Sponge urethane (low thermal conductivity member), 12 ... Shutter member, 45 ... Opening / closing plate, 51, 52 ... End in the axial direction (end on the side along the axial direction), 51a, 52a ... Bending End portion 55... Open / close cover, 55a... Tip portion, T... Unfixed toner image, P... Paper (sheet-like material), N. Fixing nip portion, L1, L2.

Claims (6)

A heating rotator and a pressurizing rotator that are press-contacted so as to form a fixing nip portion through which a sheet-like material carrying an unfixed toner image passes, and each peripheral surface of the heating rotator and pressurizing rotator Made of a synthetic resin arranged in a state of surrounding the outside of the heat reflecting plate with an interval between them, and a heat reflecting plate arranged so as to be closely enclosed in a range excluding the passage part of the sheet-like material With an exterior cover,
The end of the exterior cover facing the passage part of the sheet-like material is formed in a form that comes into contact with the heat reflecting plate except for substituting with other components
In addition, a part of the exterior cover is formed as an opening / closing cover that opens and closes so that a space of the passage portion of the sheet-like material is widened, and the front end portion of the exterior cover when the opening / closing cover is closed A fixing device, wherein the fixing device is formed in contact with a heat reflecting plate.   The fixing device according to claim 1, wherein when the opening / closing cover is closed, the opening / closing cover and the other exterior cover portion are overlapped with each other.   The fixing device according to claim 1, wherein an elastic member that fills the gap is attached to a gap that exists between the open / close cover and the other exterior cover portion when the open / close cover is closed.   The fixing device according to claim 1, wherein a low heat conductive member is attached to an outer surface of the heat reflecting plate.   The fixing device according to claim 1, wherein a part of the heat reflecting plate is formed as an opening / closing plate that opens and closes so that a space of a passage portion of the sheet-like material is widened.   Open to the exterior cover or the opening / closing cover facing the passage portion of the sheet-like material when the sheet-like material passes through the passage portion and close the opening of the passage portion when the sheet-like material does not pass. The fixing device according to claim 1, further comprising a closing shutter member.

Images