JPH063984A - Fixing unit - Google Patents

Abstract

(57) [Summary] [Object] To provide a fixing device which can obtain a shutter function without requiring a shutter as a separate member. [Structure] The fixing device is provided in a housing 44.
Book far-infrared halogen lamps 47 and 48, and cover these halogen lamps 47 and 48, and when not fixing, rotate and move around the axis of the halogen lamps 47 and 48, and between the lamps 47 and 48 and the recording paper. The movable reflectors 53 and 54 which are positioned are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device incorporated in a copying machine, a facsimile, an electrophotographic printer or the like.

[0002]

2. Description of the Related Art Electrophotographic methods are generally used in copying machines, facsimiles, printing machines and the like. In this electrophotographic method, a photoconductive phenomenon is used to form an electrostatic latent image on a photosensitive medium, and the electrostatic latent image is toner-developed into a toner image (visible image), and then the toner image is recorded. It is designed to be transferred and fixed on paper. To fix the toner image,
Several fusers are known that utilize heat, pressure, light, etc.

The most common fixing device in a copying machine, a printing machine or the like uses a heat roll as a heat source for fixing, as disclosed in Japanese Patent Publication No. 3-61942, It is known that a pressure roll is used instead. However, although the heat roll type fixing device is excellent in terms of thermal efficiency, it has a defect that it takes several tens of seconds for the initial heating (rise) of the heat roll, while the pressure roller type fixing device has a problem. Has the advantage of not requiring heat energy,
There is a problem that stable fixing becomes difficult.

Further, in the case of a heat roll or a pressure roll, the toner image is fixed by coming into contact with the recording paper, so that the toner image is crushed and the printing quality is impaired. Therefore, in order to solve the above-mentioned problems, it is conceivable to provide a lamp such as a far infrared ray lamp in the housing of the fixing device and use this lamp as a heating source. Contact can be made to fix the toner image.

[0005]

However, when the recording paper is continuous recording paper such as roll paper or fan hold paper,
This continuous recording paper is always directly heated by the lamp of the fixing device even during non-fixing.Therefore, as a safety measure, a shutter is provided between the lamp and the recording paper during non-fixing. It is necessary to prevent heating of the recording paper.

Various types of shutters of this type are known, but each of them has a single function that is used only during non-fixing, complicates the structure of the entire fixing device, and increases the number of parts. Has become a cause of increase. The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to provide a fixing device that can obtain a shutter function with a simple structure without providing a shutter as a separate member. .

[0007]

The fixing device of the present invention includes a lamp as a heating source, a heat ray from the lamp which is reflected toward the recording paper during fixing, and is rotated when not fixing. A movable reflection plate is provided between the lamp and the recording paper, and blocks the irradiation of heat rays from the lamp to the recording paper.

[0008] Preferably, the center of rotation of the movable reflector is set on the axis of the lamp.

[0009]

During fixing, the movable reflecting plate is arranged at a position sandwiching the lamp with the recording paper, and the heat ray from the lamp is reflected directly or by the movable reflecting plate toward the toner image on the recording paper. It is irradiated and fixed. On the other hand, at the time of non-fixing, the movable reflecting plate rotates and is positioned between the lamp and the recording paper to serve as a shutter, which blocks the heat rays emitted from the lamp toward the recording paper.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, an overall electrophotographic printing machine is shown schematically. This electrophotographic printing machine is roughly divided into a paper feeding device 1 and a printer device 2 arranged on the paper feeding device 1, and on the front surface of the paper feeding device 1,
The paper feed trays 3 and 4 are mounted in a two-tier structure so that they can be pulled out. In each of these paper feed trays 3 and 4,
A predetermined number of cut sheets of different sizes can be accommodated, and the cut sheets are taken out one by one from the paper feed tray and supplied to the printer device 2.

The electrophotographic printing machine can use not only cut paper but also continuous recording paper. This continuous recording paper is fed from the slit-shaped paper feed port 5 on the front surface of the printer device 2 to the inside thereof. It is supposed to be guided. A discharge tray 6 is formed on the upper surface of the printer device 2, and the cut sheet after printing is discharged onto the discharge tray 6 from a slit-shaped discharge port 7.

The printer device 2 has a housing shell, so-called clam shell, whose internal structure is schematically shown in FIGS. 2 and 3. The housing shell is composed of a fixed shell 8 fixed on the paper feeding device 1 and a movable shell 10 attached to a lower rear portion of the fixed shell 8 via a pivot 9. The side shell 10 is centered on the pivot 9 as shown in FIG.
It can be opened upward to a certain angle as shown in FIG. The paper discharge tray 6 and the paper discharge port 7 described above are formed on the movable shell 10.

A tractor feeder 11 for continuous recording paper is arranged in the front part of the fixed shell 8 and the tractor feeder 11 allows the continuous recording paper to move to a continuous arrow A1 in FIG.
It is fed into the printer device 2 from the direction. A pair of feed rollers 12 is disposed immediately downstream of the tractor feeder 11 when viewed in the direction of feeding continuous recording paper, that is, in the direction of arrow A1, and from this feed roller 12, the paper feed tray 3 is provided. 2, the cut sheets sent from 4 are shown in FIG.
It is fed into the printer device 2 from the direction of the middle arrow A2. In the figure, reference numeral 13 indicates a sheet from the sheet feeding device 1 to the feed roller 12
It shows a guide for guiding the cut sheet toward.

The continuous or cut recording paper fed by the tractor feeder 11 or the feed roller 12 is guided toward the printer kit 14. The printer kit 14 includes a kit casing 15 shown by a two-dot chain line in FIG. 2, and the kit casing 15 has upper and lower surfaces opened. The developing unit 16 and the drum unit 17 are detachably housed in the kit casing 15. Also, the kit casing 15
The lower surface of the guide plate 1 that cooperates with the guide plate 18 on the fixed shell 8 side to define the guide path for the recording paper.
9 is attached to the developing device 16, and the pinch roller 2 that cooperates with the guide roller 20 on the fixed shell 8 side is attached to the developing device 16.
1 is attached.

Immediately above the developing device 16 and the drum unit 17, an exposing device 22 using an LED (light emitting diode) as a light source is arranged so as to enter the kit casing 15. 22 is fixedly attached to the movable shell 10 instead of the kit casing 15 side. Further, a transfer unit 24 which cooperates with the photosensitive drum 23 in the drum unit 17 is arranged on the lower surface side of the kit casing 15 so as to enter the kit casing 15, and the transfer unit 24 is fixed shell 8.
It is fixedly attached to the side.

In the kit casing 15 described above, the lower portion on the rear side of the rotary shaft 2 is seen in the front-back direction of the printer device 2.
It is supported by the movable side shell 10 via 5. Therefore, as shown in FIG. 3, when the movable shell 10 is in an upwardly opened state, the kit casing 15
Can rotate downward about the rotation shaft 25 by a predetermined angle, whereby the upper surface opening of the kit casing 15 can be exposed to the outside. At this time, although not shown, the pressing between the movable shell 10 side and the developing device 16 and the drum unit 17 are also released at the same time. The space required for accommodating the kit casing 15 on the movable shell 10 side is indicated by a broken line in FIG.

When the kit casing 15 is in the position shown in FIG. 3, not only the toner cartridge 26 of the developing device 16 but also the drum unit 17 and the developing device 16 itself can be replaced. Here, it should be noted that these replacement operations are all performed from the front side of the printing machine through the top opening of the kit casing 15. That is, in the case of the printing machine of this embodiment, the developing device 1
The 6 and the drum unit 17 are not detachably attached to the kit casing 15 from the side thereof, but can be inserted and removed through the upper opening of the kit casing 15. Further, in the case of this embodiment, the toner cartridge 26 is filled with two-component toner.

As shown in FIGS. 4 and 5, the drum unit 17 rotatably supports and accommodates the above-described photosensitive drum 23 in a unit casing 27,
A part of the photosensitive surface of the photosensitive drum 23 is exposed to the outside, and in the state of FIG. Further, the unit casing 27 has a structure in which, in addition to the photosensitive drum 23, a main charger 28, a brush roll 29, and an agitating roll 30 are accommodated. Further, in the unit casing 27, the discharged toner is discharged to the outside. A recovery chamber 31 is formed integrally to store the gas without discharging it. Therefore, when the residual toner on the photosensitive drum 23 is removed by the brush roll 29, the residual toner is
Transferred from the brush roll 29 to the stirring roll 30,
Then, it is discharged from the stirring roll 30 to the recovery chamber 31.
The recovery chamber 31 has a capacity capable of storing the discharged toner until the life of the photosensitive drum 23 is reached.

A pair of handles 32 are integrally formed on the unit casing 27 to facilitate the attachment / detachment of the drum unit 17, and a drive gear 33 is attached to the drum shaft of the photosensitive drum 23. ing. Although not shown, the drive gear 33 meshes with a gear on the drive source side to drive the photosensitive drum 23 to rotate in one direction.

The printer kit 14 and the exposure device 22 described above.
The print system including the transfer unit 24 and the transfer unit 24 forms a toner image on a recording sheet as follows. Photosensitive drum 2
With rotation of 3, first, the photosensitive surface of the photosensitive drum 23 is uniformly charged by the main charger 28, and thereafter, the light beam from the exposure device 22 is applied to the photosensitive surface.
An electrostatic latent image is formed on this photosensitive surface. After that, the electrostatic latent image on the photosensitive surface is subjected to toner development by the developing device 16, and the visualized toner image is obtained on the photosensitive surface. The toner image on the photosensitive surface is transferred onto the recording paper when the recording paper passes between the photosensitive drum 23 and the transfer device 24.

After that, when the recording paper is conveyed toward the rear side of the printing device 2 by the conveyor 34, the recording paper passes directly below the fixing device 35, and at this time, the toner image on the recording paper is conveyed. Will be fixed. The conveyer belt of the conveyer conveyor 34 is a suction belt in which holes are distributed over the entire surface thereof, so that the conveyer conveyor 34 can convey the recording paper while adsorbing the recording paper. .

A fan unit 36 for generating an air flow is arranged immediately below the transfer conveyor 34.
The transfer conveyor 34 and the fan unit 36 are respectively arranged on the fixed shell 8 side except for a part of the transfer conveyor 34. That is, as is clear from FIG.
Pinch roller 34a located at the rear end of the conveyor 34
Are rotatably supported on the movable shell 10 side.

After the fixing process, if the recording sheet is a cut sheet, it is ejected from the above-mentioned sheet ejection port 7 in the direction of arrow B2 in FIG. On the other hand, if the recording paper is continuous recording paper,
2 through the paper output port (not shown) on the rear surface of the printer device 2.
It will be discharged in the middle B1 direction. Discharge guide mechanism 3
Reference numeral 7 denotes a pair of lower paper discharge rollers 38 arranged near the rear end of the conveyer 34, a pair of upper paper discharge rollers 39 arranged near the paper discharge port 7, and these paper discharge rollers. Three
A guide plate 40 that curves and extends so as to connect between 8 and 39, and guide plates 41, 42 and 4 that cooperate with the guide plate 40 to define a guide path for cut sheets.
It consists of three.

The discharge guide mechanism 37 is arranged in the movable shell 10 except for a part thereof.
The drive side roller of the lower paper discharge roller 38 and the guide plate 41 are arranged in the fixed side shell 8. If the recording paper is continuous recording paper, the guide plate 41
2 is rotated as shown by a broken line in FIG. 2, whereby the guide plate 41 also serves as a guide for continuous recording paper.

The above-mentioned fixing device 35 is the movable side shell 10
It is fixedly arranged inside, the inside of which is shown in FIG. The fixing device 35 includes a box-shaped housing 44 whose lower surface is opened.
As is clear from the above, it has a double wall structure. A predetermined space is defined between the outer wall 45 and the inner wall 46 of the housing 44, and this space is filled with a heat insulating material although not shown.

Inside the housing 44, that is, its inner wall 4
In the internal space divided by 6, as its heating source,
A pair of far-infrared halogen lamps 47 and 48 are housed. These halogen lamps 47 and 48 are indicated by 1 in FIG.
Seen in the conveyance line of the recording paper indicated by the dotted line, the housing 44 along the conveyance line has a predetermined interval and extends in parallel with each other, and its effective length is the same as that of the recording paper. It is sufficiently longer than the width dimension. Therefore, the housing 44 itself also extends in the direction orthogonal to the transport line, and its entire length is sufficiently longer than the width dimension of the recording paper. Although not shown in detail in the figure, both ends of the far infrared halogen lamps 47 and 48 are
The inner wall 46 is supported via a support tool.

The far-infrared halogen lamps 47 and 48 are obtained by coating a quartz tube of an ordinary halogen lamp with an alumina-based ceramic obtained by adding a predetermined heat-resistant black pigment, and emit far-infrared rays efficiently. And its characteristics are shown in the graph of FIG. Figure 7
In the figure, the solid line indicates the far infrared halogen lamp 4 of the embodiment.
7 and 48 show the spectral distribution characteristics, and the alternate long and short dash line and the broken line respectively show the spectral distribution characteristics of a so-called normal white-coated halogen lamp and an uncoated halogen lamp. As is clear from FIG. 7, the far-infrared halogen lamps 47 and 48 have almost 100% of visible light (0.3 to 0.7 μm) output and 70 to 80 of near infrared (0.7 to 3.0 μm) output. % Can be converted into far infrared rays (3.0 to 100.0 μm) and output, the relative radiant intensity of far infrared rays is 2 to 3 times that of ordinary halogen lamps, and the output peak is 3 to 5 μm. Existing.

As shown in FIG. 6, the far infrared halogen lamps 47 and 48 are provided with a reflector 49 from above.
Is covered by. The reflector 49 includes a central reflector 50 positioned at the center of the far infrared halogen lamps 47, 48. The central reflector 50 is made of an aluminum plate having a V-shaped cross section. The surface facing 48 is the reflecting surface 50a,
Formed as 50b. The pair of upper edges of the central reflector 50 are formed as stopper surfaces 51 that are horizontally bent toward the corresponding halogen lamps 47 and 48. Each stopper surface 51 has a buffer tape made of a heat-resistant material. 52 is attached.

As shown in FIG. 6, on both sides of the central reflector 50,
Movable reflectors 53 and 54 are arranged, respectively. These movable reflecting plates 53, 54 are made of V-shaped aluminum plates whose cross section is expanded by the central reflecting plate 50. The horizontal portion of the horizontal portion has one side edge on the stopper 51 of the central reflector 50 and the buffer tape 52.
It is in a state of overlapping from above via. On the other hand, the inclined portion extends downward from the other side edge of the horizontal portion and is inclined in the opposite direction to the facing reflecting surface on the side of the central reflector 50. The surfaces of the movable reflecting plates 53, 54 on the halogen lamp side are also formed as reflecting surfaces 50c, whereby the reflecting surfaces of the reflector 49 covering the far-infrared halogen lamps 47, 48 as a whole have their bottom sides. Has an open trapezoidal shape.

Further, on the inner wall 46 of the housing 44, a pair of fixed reflecting plates 55 and 56 are attached at the lower surface opening side. These fixed reflectors 55 and 56 are
Inner wall 4 made of aluminum plate bent in a triangular shape
It projects from 6 toward the inclined part of the movable reflection plate. Therefore, the fixed reflectors 55, 56 are arranged so that
When 4 is in the posture shown in FIG. 6, an extended portion which is continuous with the inclined portion of the corresponding movable reflection plate and whose inner surface is formed as a reflection surface 50d, and a stopper which extends from this extended portion toward the inner wall 46. It consists of parts. A buffer tape 57 made of a heat-resistant material is attached to each of the fixed reflection plates 55 and 56 from the extension to the stopper.

The above-mentioned reflector, that is, the central reflector 5
0, movable reflectors 53, 54 and fixed reflectors 55, 56
8 extends over the entire length of the far-infrared halogen lamps 47, 48 so that it becomes clearer with reference to FIG. 8, so that in the state of FIG. A ventilation chamber 58 for cooling air is defined by the portion and the reflector 49. The buffer tapes 52 and 57 described above also extend over substantially the entire length of the reflector 49, and these tapes also function as seals.

On the other hand, drive units 60 and 61 are attached to both ends of the housing 44 as shown in FIG. 8, and both end wall portions of the inner wall 46 correspond to the ventilation chambers 58. Opening 5 that communicates with the inside of the drive unit
9 are formed respectively. Only one of these openings 59 is shown in FIG. Each drive unit 60, 6
As shown by the broken line in FIG.
2 and an exhaust fan 63 are housed respectively, and by driving the intake and exhaust fans 62 and 63, outside air is introduced into the ventilation chamber 58 from the direction of arrow C1 in the figure, while the inside of the ventilation chamber 58 is Air is discharged in the direction of arrow C2 in the figure. Although not shown, the drive unit 6
Needless to say, the intake port and the exhaust port are formed at 0 and 61, respectively, and these intake port and the exhaust port are opened to the outer surface of the printer device, that is, the movable side shell 10.

Of the reflector 49 described above, the central reflector 50 and the fixed reflectors 55, 56 have both ends attached to both end wall portions of the inner wall 46 via a predetermined fixture, but the movable reflector plate. 53 and 54 have inner walls 46 at both ends.
Is rotatably supported on the end wall of the. Movable reflector 5
3, 54, the support structure at both ends is the same,
Therefore, FIG. 9 shows only the support structure on one side of the movable reflector 54. As is clear from FIG. 9, the inner wall 46
A rotary shaft 65 is attached to the end wall portion 46a of the rotary shaft 65 via a bearing 64. One end of the rotary shaft 65 projects toward the corresponding far-infrared halogen lamp, and the projecting end and the movable reflecting plate 54 are connected to each other. The spaces are interconnected by a connection plate 66.

Here, the rotary shaft 65 and the lamp shaft of the halogen lamp are positioned coaxially with each other.
Each of the movable reflection plates 53 and 54 is rotatable about the axis of the corresponding halogen lamp, that is, the lamp axis. Further, the rotating shaft 65 on the side of the drive unit 60 described above has the other end protruding into the drive unit 60, and the other end is provided with a drive gear 66 as shown in FIG. There is. That is, as shown in FIG. 8, each of the movable reflection plates 53 and 54 is provided with the drive gear 66. These drive gears 66
Is connected to the rotary solenoids 67 and 68 via a speed increasing mechanism, and an example of this speed increasing mechanism is shown in FIG.

As is apparent from FIG. 10, the rotary solenoid is arranged such that its output shaft 69 is largely eccentric from the axis of the corresponding drive gear 65.
A speed increasing disk 70 is attached. On the outer peripheral portion of the speed increasing disk 70, a sector gear 71 having internal teeth, which protrudes from the outer periphery of the rotary solenoid, is integrally formed. The sector gear 71 is meshed with the drive gear 65 from the outside. Therefore, if the drive gear 66 and the corresponding rotary solenoid are connected via the speed increasing disk 70, the rotation of the rotary solenoid is increased.
0, that is, it becomes possible to increase the speed by the sector gear 71 and transmit it to the drive gear 65.
A large rotation angle of 54 can be secured.

Referring again to FIG. 6, the housing 44
The lower opening of the is covered with a protective net 72,
Details of the protective net 72 are shown in FIGS. 11 and 12. The protective net 72 includes a rectangular frame member 73, and locking claws 74 as shown in FIG. 12 are provided at predetermined intervals in the longitudinal direction from both inner edges of the frame member 73.
Are projected integrally. The frame member 73 and the locking claw 74 can be formed simultaneously by punching an aluminum plate, for example, by pressing, and the locking claw 74 on one inner edge and the locking claw 74 on the other inner edge can be formed. , Their formation pitches are offset by half a pitch from each other.

The locking claws 74 on both inner edges of the frame member 73 are
A metal wire made of a tungsten wire and a wire material 75 made of a heat-resistant synthetic resin such as polyamide-imide are alternately wound around each other, whereby a net surface is formed by the wire material 75. Here, it should be noted that the wire material that defines the net surface is slightly inclined in the recording paper conveyance direction, as indicated by the dashed-dotted line in FIG.

According to the above-mentioned fixing device 35, when the recording paper passes on the conveying line immediately below the fixing device 35, the toner image on the recording paper and the recording paper are paired with the pair of far-infrared halogen lamps 4.
It is rapidly heated by the radiant heat from 7, 48, whereby the toner image is fixed. Here, the far infrared rays emitted from the halogen lamps 47 and 48 are efficiently absorbed regardless of the color of the toner, so that the toner is reliably melted. Further, at this time, the recording paper itself is also heated by the far infrared rays at the same time, so that the melted toner and the recording paper become well compatible with each other, and high-quality fixing can be obtained.

Further, far infrared halogen lamps 47, 48
Since the operating temperature reaches the operating temperature in a short time, not only the warming-up time can be significantly shortened, but also the heat generation amount can follow the change of the input voltage, and the temperature can be easily adjusted. During the fixing process, the suction fan 62 and the exhaust fan 63 are driven, so that the outside air is constantly flowing through the ventilation chamber 58. The airflow flowing in the ventilation chamber 58 takes heat from not only the inner wall 46 but also the reflector 49, that is, the fixed reflection plate 50, the movable reflection plates 53 and 54, and the fixed reflection plates 55 and 56, and this heat is generated by the air. Along with this, it is discharged to the outside of the printer device 2. Therefore, the inner wall 46 and the reflector 49
Is not overheated, and the temperature rise in the printer device due to the heat from the inner wall 46 and the reflector 49 can be reduced.

Further, during fixing, the chamber on the halogen lamp side and the ventilation chamber 58 are partitioned by the reflector 49, so that the halogen lamps 47 and 48 are not cooled by the air flow in the ventilation chamber 58, and Far-infrared lamp 47,
It does not reduce the thermal efficiency of 48. On the other hand, during non-fixing such as when the printing machine is on standby or when it is stopped, the rotary solenoids 67 and 68 are driven to move the pair of movable reflection plates 5 to each other.
The movable reflectors 53 and 54 are rotated in the opposite directions to each other, so that the movable reflectors 53 and 54 are, as shown by the solid line in FIG.
It can be located between the corresponding halogen lamp and the protective net 72. That is, as shown in FIG. 13, one movable reflecting plate 53 is rotated clockwise until one side edge thereof comes into contact with the stopper portion of the fixed reflecting plate 55 via the buffer tape 57, and the other movable reflecting plate 54 is rotated. , And is rotated counterclockwise until its one side edge comes into contact with the stopper portion of the fixed reflection plate 56 via the buffer tape 57.

When the movable reflectors 53 and 54 are in the rotating position shown in FIG. 13, the far infrared halogen lamps 47 and 48 are included in the ventilation chamber 58 described above, and these halogen lamps 47 and 48 are ventilated. It is cooled directly by the air flow in the chamber 58. Therefore, at the time of non-fixing, the far infrared halogen lamps 47 and 48 can be quickly cooled.

When the recording paper, that is, the continuous recording paper is present immediately below the fixing device 35, the movable reflecting plates 53 and 54 located at the rotating position in FIG.
The radiant heat radiated from 8 toward the continuous recording paper is shielded, and as a result, the movable reflecting plates 53 and 54 also function as shutters. Therefore, even when the printing machine is not in a stand-by state or when it is not fixed, for example, the far infrared halogen lamps 47, 4
Even if 8 is turned on, these halogen lamps 47, 4
The continuous recording paper is not directly exposed to the radiant heat from 8, and the continuous recording paper is reliably prevented from overheating, which is an excellent safety measure.

On the other hand, when printing is restarted or started while the printing machine is on standby or stopped, the movable reflecting plates 53, 5 are used even if continuous recording paper exists immediately below the fixing device 35.
Since the continuous recording paper is protected by the shutter function of 4, the far infrared halogen lamps 47 and 48 can be rapidly raised to the operating temperature. Furthermore, since the center of rotation of the movable reflectors 53 and 54 is on the corresponding lamp axis of the halogen lamp as described above, the movable reflectors 53 and 54 rotate from the rotational position of FIG. 6 to the rotational position of FIG. In this case, it also has an advantage that the moving distance of the movable reflecting plates 53 and 54 is minimized.

Moreover, in the case of this embodiment, since the rotation of the rotary solenoids 67, 68 is transmitted to the drive gear 66, that is, the corresponding movable reflecting plate via the sector gear 71 of the speed increasing disk 70, the rotary solenoid is used. Even if the maximum allowable rotation angles of the solenoids 67 and 68 are small, the rotation angles of the movable reflecting plates 53 and 54 can be sufficiently secured. Further, since the lower surface opening of the fixing device 35 is covered with the protective net 72, the far infrared halogen lamp 4 whose recording paper is a heat source is used.
There is also no possibility of undesirably approaching the recording mediums 7 and 48 and causing overheating of the recording paper. Explaining this point in detail, when the recording paper is a cut paper, the front edge of the cut paper does not enter the fixing device 35 when viewed in the conveying direction, and the cut paper and the halogen lamps 47 and 48 are brought into contact with each other. It can be surely prevented, and the safety measures will be even better.

The wire 75 of the protective net 72 is shown in FIG.
As is clear from FIG. 1, since the recording paper is obliquely inclined with respect to the conveying direction, the entire surface of the recording paper can receive the radiant heat from the far infrared halogen lamps 47 and 48 uniformly. In other words, when the recording paper passes directly below the fixing device 35, there is no portion on the recording paper that is always shaded by the wire rod 75 of the protective net 72, which also improves the quality of fixing. Moreover, even if the recording paper is a cut paper, the front edge of the recording paper is not caught by the wire rod 75 of the protective net 72 when viewed in the carrying direction thereof, which does not hinder the transportation.

Further, when the recording paper is continuous recording paper, when it is not fixed, the continuous recording paper is doubly protected by the protective net 72 in addition to the movable reflecting plates 54, 54 functioning as shutters. Therefore, it is even better in terms of safety measures. The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, although the fixing device applied to the electrophotographic printing machine has been described in the embodiment, the present invention is also applicable to the fixing device of a copying machine or a facsimile.

The movable reflectors 53 and 54 may be formed integrally with each side of the central reflector 50, and the shape thereof is not limited. Further, in one embodiment, the fixing device uses two far-infrared halogen lamps, but the number of lamps is not limited to that of the embodiment, and may be one. Further, it may be three or more.

[0048]

As described above, the fixing device of the present invention has a simple structure in which the reflector of the lamp as the heating source can be rotated, and the movable reflector is rotated when the fixing is not performed. The movable reflector can be used as a shutter by positioning it between the lamp and the recording paper. Therefore, since the shutter is not required as a separate member, the number of parts is not increased, and the structure is simplified, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a printing machine.

FIG. 2 is a schematic diagram showing an internal structure of a printer device of the printing machine of FIG.

FIG. 3 is a schematic view showing a state where a movable side shell of the printer device of FIG. 2 is opened.

FIG. 4 is a front view of a drum unit of the printer device of FIG.

5 is a cross-sectional view of the drum unit taken along line VV in FIG.

FIG. 6 is a sectional view of the fixing device of FIG.

FIG. 7 is a graph showing a comparison of spectral distributions of a far-infrared halogen lamp and a normal halogen lamp.

FIG. 8 is a bottom view of the fixing device of FIG.

FIG. 9 is a cross-sectional view showing a support structure on one end side of a movable reflecting plate.

FIG. 10 is a cross-sectional view showing a speed increasing disk that connects a drive gear on the side of a movable reflector and a rotary solenoid.

FIG. 11 is a plan view showing a protective net of the fixing device of FIG.

12 is an enlarged view of a portion XII in FIG.

FIG. 13 is a cross-sectional view of the fixing device showing a rotational position when the movable reflecting plate functions as a shutter.

[Explanation of symbols]

 35 Fixing device 44 Housing 47,48 Far infrared ray halogen lamp 50 Central reflector 53,54 Movable reflector 55,56 Fixed reflector 72 Protective net

Claims (2)

[Claims] 1. A fixing device for heating and fixing a toner image on a recording paper, wherein a lamp as a heating source and, during fixing, heat rays from the lamp are reflected toward the recording paper to fix the toner image. A fixing device comprising: a movable reflection plate which is sometimes rotated and positioned between the lamp and the recording paper to block irradiation of heat rays from the lamp to the recording paper. 2. The fixing device according to claim 1, wherein the rotation center of the movable reflecting plate is on the axis of the lamp.