JPH0716946U - Heat roller type fixing device - Google Patents

Abstract

(57) [Abstract] [Purpose] When the heat roller is maintained at a predetermined set temperature via the thermostat, the thermostat is arranged separately from the heat roller, and the space distance between the thermostat and the heat roller is different for each device. It is an object of the present invention to provide a heat roller type fixing device capable of reliably suppressing the variation in the set temperature of the heat roller even when the temperature changes to. A heat roller, a press roller which is arranged so as to be in rolling contact with the heat roller, and which holds an object to be fixed between the heat roller, and a heat roller, which are arranged apart from the heat roller and operate at a predetermined temperature. The present invention is characterized by including a thermostat and a heat transfer member that connects the thermostat and the heat roller to each other so as to transfer heat.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to, for example, a heat roller type fixing device used in an electrophotographic apparatus having an image forming unit utilizing an electrophotographic method.

[0002]

[Prior art]

 BACKGROUND OF THE INVENTION Conventionally, an electrophotographic apparatus having an image forming means using an electrophotographic method includes a photosensitive drum, a transfer charger that transfers a toner image formed on the outer peripheral surface of the photosensitive drum to the surface of paper, and the transfer charger. And a fixing device for fixing the toner image transferred on the surface of the sheet by heat. As the fixing device, recently, a pair of fixing rollers rollingly contacting each other, specifically, a heat roller type including a heat roller and a press roller (backup roller) rollingly contacting the heat roller at a predetermined pressure is used. The structure is adopted, and the fixing operation is performed with the rotation of both fixing rollers, and the sheet is conveyed toward the discharge port.

Here, in the conventional fixing device, the heat roller has a predetermined constant temperature (for example, the fixing temperature is set during the fixing operation, and the standby temperature is set lower than the fixing temperature in the standby state). For example, a thermostat is used in a state of being in contact with the outer peripheral surface of the heat roller in order to heat it using a built-in halogen lamp or the like. Conventionally, this thermostat is arranged so as to face the position of the heat roller after cleaning so that the toner adhering to the heat roller is less likely to adhere to the thermostat.

[0004]

[Problems to be solved by the device]

 Here, in order to suppress the adhesion of the toner to the thermostat as much as possible, a so-called non-contact type in which the thermostat is arranged away from the surface of the heat roller, which is separated from the surface of the heat roller, is preferable. However, if the thermostat is separated from the surface of the heat roller in this way, a certain spatial distance will always exist between them. The air existing in this space distance functions as a kind of heat insulating material, so even if this space distance changes even a little, the amount of heat influence from the heat roller (transfer amount) changes and the thermostat is activated. There was a risk that the temperature of the heat roller would fluctuate, and there was a demand for a solution.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to keep the heat roller from the heat roller when the heat roller is kept at a predetermined set temperature via the thermostat. It is an object of the present invention to provide a heat roller type fixing device which is arranged separately and can reliably suppress the variation in the set temperature of the heat roller even if the spatial distance between the thermostat and the heat roller changes from device to device.

[0006]

[Means for solving the problem]

 In order to solve the above-mentioned problems and to achieve the object, a heat roller type fixing device according to the present invention is, according to the first aspect of the invention, provided with a heat roller and a heat roller so as to be in rolling contact with the heat roller. A press roller that holds an object to be fixed between the heat roller, a thermostat that is arranged apart from the heat roller and that operates at a predetermined temperature, and a heat transfer member that connects the thermostat and the heat roller to each other so that heat can be transferred. It is characterized by having and.

[0007]

【Example】

 The structure of an embodiment of the heat roller type fixing device according to the present invention will be described in detail below with reference to the accompanying drawings when the structure is applied to an electronic facsimile device.

As shown in FIG. 1, the electronic facsimile apparatus 10 of this embodiment automatically reads the image information of the transmission originals, which are set on a plurality of sheets at a time, one by one, and calls the read image information by telephone. The image information sent from the facsimile machine on the receiving side of the other party using a line and the image information transmitted from the facsimile machine on the other side of the receiving party is sent through the electrophotographic method using the laser scanning method. In the embodiment, it is configured so that it can be transferred (image formation) to cut plain paper. On the other hand, the electronic facsimile apparatus 10 is configured to have a so-called electronic copying function capable of copying (forming an image) the image information read from a document on a built-in paper. Further, the electronic facsimile apparatus 10 has a so-called printer function capable of transferring (image forming) the image information transmitted from, for example, the information processing apparatus to a sheet having a built-in via a connection line other than a telephone line. Is also configured.

This electronic facsimile machine 10 is mounted on the upper surface of the main plate 12 and the main plate 12 arranged substantially parallel to the mounting surface thereof, and has the above-mentioned image forming function. The print mechanism 14 to be carried and a swing frame (not shown) rotatably supported by the rear end of the main plate 12 and swingably attached to the main plate 12 are arranged as described above. An image reading mechanism 16 having an image reading function, a control panel 18 having a rear end rotatably supported by an intermediate portion of the swing frame and swingable with respect to the swing frame, and the main unit described above. A laser scanning unit 20, which is attached to the lower surface of the plate 12 and has a function of forming a latent image on the outer peripheral surface of a photosensitive drum (described later) in the print mechanism 14, is schematically illustrated. I have it.

Here, in the center of the rear part of the upper housing 22, which constitutes the upper part of the housing of the electronic facsimile apparatus 10, a paper feed cassette 24 is inserted, and a paper feed cassette mounting opening 22a also serving as a transfer paper take-in port is formed. Further, document intake ports 22b for receiving the transmission documents are formed in front of the attachment ports 22a, respectively. Although not described, the paper feed cassette 24 is configured so that a large number of paper sheets of a predetermined size can be accommodated together in a batch. Further, the printer housing 26, which constitutes an intermediate portion of the housing of the electronic facsimile apparatus 10, is provided with a paper ejection port 26a for ejecting the paper on which the image information is transferred on the lower surface in a state of being positioned downward. A document discharge port 26b is formed above the paper discharge port 26a for discharging the transmitted document after the reading operation. On the other hand, a document tray 28 on which a document to be transmitted is placed is detachably attached to the above-mentioned document intake port 22b.

Although not shown, various operation buttons a are provided on the upper surface of the control panel 18 described above, and a display window provided with a liquid crystal display device for displaying predetermined information to an operator. Is provided. Here, although not shown, an upper housing release button is provided on the right side of the front surface of the control panel 18. By rotating the upper housing release button so as to push it up, the lock of the rocking frame on the main plate 12 is unlocked, and the rocking frame and the upper housing 22 attached thereto are both rotated upward. You will be able to move. As a result, the upper opening of the printer housing 26, that is, the upper surface of the print mechanism 14 is opened over almost the entire surface, and the operation of removing the paper jammed during the conveyance and the maintenance of each mechanism portion constituting the print mechanism 14 are performed. It will be easy to do.

On the other hand, on the immediate left of the upper housing release button, a control panel release button (not shown) is arranged adjacent to the upper housing release button. This control panel release button is rotatably attached to the control panel 18, and by rotating it so as to push it down, the lock of the control panel 18 in the closed state to the swing frame is released. The control panel 18 can be rotated upward from the upper housing 22. As a result, the front opening of the upper housing 22, that is, the upper surface of the image reading mechanism 16 is opened over substantially the entire surface, and an operation of removing a document jammed during conveyance and each mechanism portion constituting the image reading mechanism 16 are opened. It will be possible to easily carry out maintenance and the like.

Next, the configuration of the image reading mechanism 16 described above will be schematically described. The image reading mechanism 16 is provided with a document transport path 30 for transporting a document (at least one document) placed on a document tray 28 to the document discharge port 26b described above. Further, the image reading mechanism 16 separates the originals placed on the original tray 28 into one sheet by the original document separation unit 32 and the original document take-out roller 34, and takes out the separated one original sheet. As the roller 34 rotates, it is taken out forward, conveyed between the image reader 36 and the white roller 38, and the image reader 36 reads the image of the original document to be transmitted (or copied), and the original document is conveyed. It is configured so as to pass through the feeding path 30 and be further forwarded by a pair of document discharge rollers 40a and 40b arranged at the outlet, and to be discharged to the outside of the housing through the above-described document discharge port 26b. There is.

By depressing the control panel release button described above, the control panel 18 is rotated upward from the upper housing 22 as described above, and along with this rotation, the control panel 18 and the image reader are rotated. Due to the action of the upper coil spring 42a interposed between the image reader 36 and the upper housing 22, the lower coil spring 42b interposed between the image reader 36 and the upper housing 22 causes the image reader 36 to move to the white roller 38. Will be separated from above.

The configuration of the print mechanism 14 described above will be schematically described below. First, the print mechanism 14 transmits image information read from an original document via the image reading mechanism 16 or a communication line, specifically, a telephone line in this embodiment. Based on the received image information, the image formation, that is, the image is printed on the paper P taken out from the paper feed cassette 24. Therefore, the print mechanism 14 receives the paper P taken out from the paper feed cassette 24 according to the rotation of the paper feed roller 44 from the paper take-in port 22 a formed in the rear portion of the upper surface of the upper housing 22 to the printer housing 26. A paper transport path 46 for transporting to the paper discharge port 26a formed on the front surface is provided.

In addition, the print mechanism 14 is a pair of upper and lower parts for defining the transport timing of the paper P from the upstream side toward the downstream side in the transport direction of the paper P 1 along the paper transport path 46. The registration rollers 48a and 48b, the photosensitive layer 50 attached to the outer peripheral surface, and the photosensitive drum 50 on which the electrostatic latent image corresponding to the image is formed by the image exposure by the laser scanning unit 20 described above, and the lower surface of the paper P. A fixing device 52 for fixing the transferred toner image is sequentially provided.

Here, the photosensitive drum 50 and the fixing device 52 are driven via a printer driving mechanism (not shown), and the photosensitive drum 50 is rotationally driven in the clockwise direction in the figure. Further, on the outer periphery of the photosensitive drum 50, a charging charger 54 for uniformly charging the outer peripheral surface of the photosensitive drum 50, which is positioned immediately below the photosensitive drum 50, is provided. Further, an image exposure portion IE by the laser scanning unit 20 described above is defined at a position along the rotation direction of the photosensitive drum 50 from the charger 54, and the rotation direction of the photosensitive drum 50 is defined from the image exposure portion IE. A developing device 56 for developing the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 50 by image exposure with toner is disposed at the above position.

Further, at a position along the rotation direction of the photosensitive drum 50 from the developing device 56 and immediately above the outer periphery of the photosensitive drum 50, the toner image visualized by the toner is printed on the paper. A transfer charger 58 for transferring to the lower surface is provided. Further, in a position along the rotation direction of the photosensitive drum 50 from the transfer charger 58 and on the front side of the above-mentioned charging charger 54, the residual toner after the transfer is collected to collect the residual toner on the photosensitive drum 50. A cleaning blade 60 for cleaning the outer peripheral surface is provided.

It should be noted that a sheet of paper that has undergone a transfer operation (that is, toner has been transferred) has passed through a transfer portion defined between the photosensitive drum 50 and the transfer charger 58, and the leading end of the paper is the fixing device 52. A guide member 62 for guiding the upper surface of the paper P is provided between the transfer portion and the fixing device 52.

Next, with reference to FIG. 2, the fixing device 52, which is a feature of the present invention, will be described.

As shown in FIG. 2, the fixing device 52 includes a fixing housing 64 fixed on the main plate 12 described above, and a pair of upper and lower fixing rollers 66 and 68 arranged in the fixing housing 64. Is equipped with. Here, the paper transport path 46 positioned in the fixing device 52 is set to extend in a state in which the height is gradually lowered along the paper transport direction. ing. That is, the opening 70 that defines the inlet of the paper transport path 46 in the fixing device 52 is formed on the upper surface of the fixing housing 64 and on the upstream side in the paper transport direction, and the outlet of the paper transport path 46 is formed. An opening 72 defining a portion is formed in the lower portion of the front surface of the fixing housing 64. The sheet conveying path 46 is set to have a substantially straight line shape inside the fixing housing 64, specifically, a substantially straight line shape inclined at a predetermined angle with respect to the extending surface of the main plate 12. There is.

The above-described lower fixing roller 68 is a heat roller below the sheet conveying path 46 in the fixing housing 64, and is fixed in its disposition position (that is, the rotation axis) as a heat roller. Is pivotally supported in the state of being rotated clockwise in the figure. That is, the lower fixing roller 68 is provided with a hollow sleeve 68a coaxially arranged on the outer periphery of a shaft portion which is rotationally driven by a rotation driving mechanism (not shown), and inside the hollow sleeve 68a. And a heating lamp (for example, a halogen lamp) 68b for heating from one side.

On the other hand, the above-described upper fixing roller 66 is defined as a press roller that rolls against a lower fixing roller (heat roller) 68 at a predetermined pressure, and both ends of the shaft portion are rotatably supported by the fixing housing 64. 66a, and an elastic roller portion 66b coaxially fixed to the outer circumference of the shaft portion 66a.

Here, a line segment L connecting the rotation centers of the upper fixing roller 66 and the lower fixing roller 68 is set so as to extend in a state of being substantially orthogonal to the paper transport path 46. . In other words, the rotation center of the upper fixing roller 66 is set so as to pass through the rotation center of the lower fixing roller 68 and be positioned on the line segment L orthogonal to the paper transport path 46. The upper fixing roller 66 is urged by a coil spring 74 interposed between the shaft portion 66a and the fixing housing 64 so as to be pressed against the lower fixing roller 68. As a result, the paper P after transfer, which has been carried into the fixing device 52 through the above-described entrance opening 70, contacts the lower fixing roller 68 at the lower surface on which the toner image is transferred, and also performs the upper fixing. While the roller 66 is pressed against the lower fixing roller 68, the rolling contact portions of the upper and lower fixing rollers 66 and 68 pass with each other as the lower fixing roller 68 rotates. The toner image is fixed on the lower surface of the paper P by the heat from 68. In this way, the fixing operation is completed, and the toner is discharged to the outside of the fixing housing 64 through the outlet opening 72.

Here, in this embodiment, the lower surface of the paper P on which the toner image is transferred is heated via the lower fixing roller 68 to fix the toner image on the lower surface. Therefore, the lower surface of the paper P heated by the lower fixing roller 68 is in a state of being dried as compared with the upper surface by heating. As a result, the paper P after fixing tends to curl in a convex state. In consideration of such a curled state of the paper P, in this embodiment, the lower surface of the paper conveyance path 46 is defined on the outer peripheral surface of the lower fixing roller 68 while supporting the lower surface of the paper P after the fixing operation. The paper ejection guide 76 is disposed so that its tip is in contact with the paper ejection guide 76. By disposing the sheet discharge guide 76 in this manner, even if the sheet P is curled by heating, it is surely discharged from the fixing housing 64 through the outlet opening 72.

As shown in FIG. 2, the lower fixing roller 68 described above functions as a heat generating roller, and is configured to directly contact the lower surface of the paper P to fix the toner image. ing. Therefore, by repeating the fixing operation, the toner powder forming the toner image gradually adheres to the outer peripheral surface of the lower fixing roller 68, and the outer peripheral surface is soiled by the adhered toner powder. In order to prevent such contamination by toner powder, an oil felt 78 as a cleaning member is pressed against the outer peripheral surface of the lower fixing roller 68. That is, the oil felt 78 is made of a felt material, and is formed by impregnating the felt material with a predetermined lubricating oil.

By thus bringing the oil felt 78 into pressure contact with the outer peripheral surface of the lower fixing roller 68, the toner powder adhering to the outer peripheral surface of the lower fixing roller 68 is wiped off by the oil felt 78. The outer peripheral surface of the lower fixing roller 68 is always maintained in a clean state free of toner powder, and the paper P is effectively prevented from being contaminated by the toner powder.

Here, as is clear from the above description, the oil felt 78 has a role of contaminating the outer peripheral surface of the lower fixing roller 68 by being polluted by toner powder. As a result, the oil felt 78 needs to be frequently replaced or cleaned. For this reason, the oil felt 78 is attached to the lower end of the insertion member 80 that is easily removable from the fixing housing 64. The insertion member 80 is set so as to be taken into the fixing housing 64 from the above-described inlet opening 70 while traversing the above-described sheet conveying path 46 from above. An opening 80a for allowing the passage of the paper P is formed in a portion of the paper sheet 80 facing the paper transport path 46 in the width direction of the paper transport path 46.

In order to surely guide the paper P having the toner image transferred thereto into the fixing device 52, the paper P is conveyed from immediately above the opening 80 a of the insertion member 80 along the paper conveyance path 46 in the paper conveyance direction. A guide member 82 extending toward the upstream side is integrally connected.

As described above, the guide member 82 is integrally attached to the insertion member 80, so that the sheet P after transfer, which has been taken out from the above-mentioned transfer portion, has its leading end abutted on the guide member 82. After that, the sheet is conveyed along the guide member 82, and the conveying direction is corrected so as to be directed to the fixing device 52. As a result, the sheet of paper P after transfer, which is taken into the fixing device 52 through the inlet opening 70, is securely in the rolling contact portion between the pair of upper and lower fixing rollers 66 and 68 in the state along the sheet conveying path 46. Will be transported to.

Here, as shown in FIG. 2, in the fixing housing 64, a heating lamp such as a built-in halogen lamp is installed so that the temperature of the outer peripheral surface of the lower fixing roller (heat roller) 68 becomes a predetermined temperature. A thermostat for controlling heating using 68b is provided. Specifically, as shown in FIG. 3, the first thermostat 84 that is turned on and off so that the temperature of the outer peripheral surface of the lower fixing roller 68 on the left side in the figure becomes a fixable temperature during the fixing operation. And the second thermostat 86 that is turned on and off so that the temperature of the outer peripheral surface of the lower fixing roller 68 on the right side in the figure becomes a fixing enable temperature during the fixing operation. It is attached to the fixing housing 64 in a state of being separated from. Although not shown, the first and second thermostats 84 and 86 are connected in parallel to a control terminal of a power source (not shown) for energizing the heating lamp 68b.

Further, the first and second thermostats 84 and 86 are both located on the upstream side in the rotation direction of the lower fixing roller 68 with respect to the position where the oil felt 78 as the above-mentioned cleaning member is arranged. Are arranged.

In this embodiment, as shown in FIG. 3, the first heat transfer member is provided between the first thermostat 84 and the outer peripheral surface of the lower fixing roller 68 at the left end in the figure. The first metal plates 88 are connected to each other so as to be able to transfer heat. That is, one end of the first metal plate 88 is in direct contact with the outer peripheral surface of the lower fixing roller 68 at the left end in the figure, and the other end thereof is in direct contact with the first thermostat 84. Touching. A second metal plate 90 serving as a second heat transfer member is connected between the second thermostat 86 and the outer peripheral surface of the right side end portion of the lower fixing roller 68 so as to be able to transfer heat to each other. ing. That is, one end of the second metal plate 90 is in direct contact with the outer peripheral surface of the lower fixing roller 68 at the right end in the figure, and the other end thereof is in direct contact with the first thermostat 84. Touching. Thus, in this embodiment, the first and second metal plates 88, 90 are configured separately (independently) from each other.

As described above, in this embodiment, the thermostats 84 and 86 are arranged so as to be separated from the outer peripheral surface of the lower fixing roller (heat roller) 68 which is a heating control target (that is, a temperature detection target). Therefore, it is possible to surely prevent the thermostats 84 and 86 from being contaminated by the toner attached to the lower fixing roller 68.

Further, conventionally, in order to suppress the adhesion of the toner to the thermostat, it has been necessary to dispose the position of the thermostat downstream of the cleaning position in the rotation direction of the heat roller. In this embodiment, as described above, since the thermostats 84 and 86 are arranged apart from the outer peripheral surface of the lower fixing roller (heat roller) 68 which is the heating control target (that is, the temperature detection target), The arrangement position is not restricted by the relationship with the cleaning position on the lower fixing roller 68, and the degree of freedom in design is greatly increased.

Further, in this embodiment, for example, the spatial distance between each of the first and second thermostats 84 and 86 and the outer peripheral surface of the lower fixing roller 68 varies depending on the manufactured plurality of fixing devices. Even so, the heat transfer from the lower fixing roller 68 to the first and second thermostats 84, 86 is substantially transferred via the corresponding first and second metal plates 88, 90, respectively. Since it is governed by heat, the first and second thermostats 84, 86 in each manufactured fixing device must operate correctly when the outer peripheral temperature of the lower fixing roller 68 always reaches a predetermined temperature. Therefore, the reliability of operation is improved. In other words, when the lower fixing roller 68 is kept constant at each set temperature via the first and second thermostats 84 and 86, the first and second thermostats 84 and 86 and the lower fixing roller 68 are held. Even if the spatial distance between the lower fixing roller 68 and the apparatus changes, it is possible to reliably suppress the variation in the set temperature of the lower fixing roller 68.

There is no problem when performing a fixing operation on a sheet having a width extending along the axial direction of the lower fixing roller 68. For example, the length of the lower fixing roller 68 along the axial direction of the left half in the figure is not limited. When a fixing operation is performed on a sheet having a width extending over a range (that is, a small sheet), the heat is absorbed by the sheet, and the temperature of only the left half of the lower fixing roller 68 in the figure decreases. However, in the above-described embodiment, the first and second thermostats 84 and 86 as the thermostats are configured to operate at the temperatures of the left and right outer peripheral surfaces of the lower fixing roller 68, and the first and second thermostats are used. Since the thermostats 84 and 86 are connected in parallel to the power source of the heating lamp 68b, the first thermostat 84 corresponding to the left half of the lower fixing roller 68 whose temperature has decreased is turned on. Then, since the heating lamp 68b is heated, the partial temperature decrease of the lower fixing roller 68 due to the heat absorption to the small-sized paper due to the fixing operation is effectively suppressed, and the small-sized paper is supplied. Even if this happens, it is possible to securely fix the heat.

Needless to say, the present invention is not limited to the configuration of the above-described embodiment and can be variously modified without departing from the scope of the present invention.

For example, in the above-described embodiment, the case where the fixing device 52 is applied to an electronic facsimile device has been described. However, the present invention is not limited to such a configuration, and for example, electronic copying is possible. It goes without saying that any device such as an electronic printer device can be applied as long as it can thermally fix an unfixed image transferred on a sheet.

Further, in the above-described embodiment, the lower fixing roller 68 is described as a heat roller, but the present invention is not limited to such a structure, and for example, the upper fixing roller 66 is used. It goes without saying that it can also be applied to the case of configuring as a heat roller.

Further, in the above-described embodiment, both the first and second thermostats 84 and 86 rotate the lower fixing roller 68 more than the arrangement position of the oil felt 78 as the cleaning member described above. Although it has been described that the first and second thermostats 84 and 86 are disposed at the upstream side in the direction, the present invention is not limited to such a configuration. It goes without saying that the oil felt 78 as a member may be arranged downstream of the lower fixing roller 68 in the rotational direction.

Further, in the above-described embodiment, the first and second thermostats 84 and 86 are provided on the lower fixing roller 68 through the corresponding first and second metal plates 88 and 90, respectively. Although it has been described that the outer peripheral surfaces on the left and right sides are respectively connected to each other so as to be able to transfer heat, the present invention is not limited to such a configuration, and, for example, the first thermostat 84 is provided on the lower fixing roller 68. The second thermostat 86 is arranged so as to face the outer peripheral surface of the central portion, and the second thermostat 86 faces the outer peripheral surface of the left end portion (or right end portion in the drawing) of the lower fixing roller 68. It goes without saying that it may be configured to be installed.

Further, in the above-described embodiment, the description has been made such that the first and second thermostats 84 and 86 are provided as thermostats, but the present invention is not limited to such a configuration, and a single thermostat is provided. It goes without saying that the thermostat may be composed of one thermostat or may be composed of an arbitrary number of thermostats of three or more. That is, in the present invention, any number of thermostats may be provided.

[0044]

[Effect of device]

 As described in detail above, by constructing the present invention, when the heat roller is kept constant at a predetermined set temperature via the thermostat, the thermostat is separated from the heat roller, and the thermostat and the heat roller are separated from each other. It is possible to provide a heat roller type fixing device capable of reliably suppressing the variation in the set temperature of the heat roller even if the spatial distance changes from device to device.

[Submission date] August 19, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

There is no problem in the case of fixing the paper having a width extending along the axial direction of the lower fixing roller 68. For example, the length of the lower fixing roller 68 along the left half of the drawing in the axial direction is not a problem. When a sheet having a width across a range (that is, a small sheet) is fixed, heat is absorbed by the sheet, and the temperature of only the left half of the lower fixing roller 68 in the figure decreases. . However, in the above-described embodiment, the first and second thermostats 84 and 86 serving as thermostats are configured to operate at the temperatures of the left and right outer peripheral surfaces of the lower fixing roller 68, and the first and second thermostats are configured to operate. Since the second thermostats 84 and 86 are configured to be connected in parallel to the power source of the heating lamp 68b 2, the first thermostat 84 corresponding to the left half of the lower fixing roller 68 whose temperature has dropped is turned on. In operation, the heating lamp 68b is heated. That is, even if the temperature of the lower fixing roller 68 is partially lowered due to the heat absorption to the small sheet due to the fixing operation, the lower fixing roller 68 is heated accordingly, and the small sheet is Even when supplied, it can be reliably fixed.

[Brief description of drawings]

FIG. 1 is a front sectional view schematically showing an internal configuration of an electronic facsimile apparatus to which a configuration of an embodiment of a heat roller type fixing device according to the present invention is applied.

FIG. 2 is a front sectional view showing a structure of a heat roller type fixing device mounted on the electronic facsimile apparatus shown in FIG.

FIG. 3 is a side sectional view showing a mounting manner of a thermostat in the heat roller type fixing device shown in FIG.

[Explanation of symbols]

IE image exposure part 10 electronic facsimile device 12 main plate 14 printing mechanism 16 image reading mechanism 18 control panel 20 laser scanning unit 22 upper housing 22a paper feed cassette mounting opening 22a also serving as a transfer paper taking-in opening 22 22b document taking-in opening 24 paper feeding cassette 26 Printer Housing 26a Paper Ejection Port 26b Document Ejection Port 26b 28 Document Tray 30 Document Conveying Path 32 Document Separation Unit 34 Document Ejection Roller 36 Image Reader 38 White Roller 40a; 40b Document Ejection Roller 42a; 42b Upper and Lower Coil Springs 44 Paper Feed Roller 46 Paper transport path 48a; 48b Registration roller 50 Photosensitive drum 52 Fixing device 54 Charging charger 56 Developing device 58 Transfer charger 60 Cleaning blade 62 Guide member 64 Fixing housing 66 Upper fixing roller (press roller) 66a Shaft portion 66b Elastic roller portion 68 Lower fixing roller 68a Hollow sleeve 68b Heating lamp 70 Inlet opening 72 Outlet opening 74 Coil spring 76 Paper ejection guide 78 Oil felt 80 Insertion member 80a Opening 82 Guide member 84 First thermostat 86 Second thermostat 88 First metal plate 90 Second metal plate.

Claims (5)

[Scope of utility model registration request] 1. A heat roller, a press roller which is arranged so as to be in rolling contact with the heat roller, and which holds an object to be fixed between the heat roller, and a heat roller, which is arranged apart from the heat roller at a predetermined temperature. A heat roller type fixing device comprising: a thermostat that operates and a heat transfer member that connects the thermostat and the heat roller so as to transfer heat to each other. 2. The heat transfer member according to claim 1, wherein the heat transfer member is composed of a metal plate that is partially in contact with the outer peripheral surface of the heat roller and is in contact with the thermostat at another part. Roller type fixing device. 3. The first thermostat, wherein the thermostat operates by heat of one part of the heat roller,
The heat roller type fixing device according to claim 1, further comprising a second thermostat which operates by heat of the other part of the heat roller. 4. The heat transfer member includes a first metal plate connecting the first thermostat and the heat roller to each other, and a second metal plate connecting the second thermostat and the heat roller to each other. The heat roller fixing device according to claim 3, further comprising a plate. 5. The one part includes a part on one end side of the heat roller, and the other part includes a part on the other end side of the heat roller. Item 5. A heat roller type fixing device according to item 3.