JPH10319761A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of operating in a shorter warm-up time with less energy consumption by reducing the loss of heat energy during roller heating to make the temperature rise of a fixing roller faster. SOLUTION: A fixing device has a fixing roller 100 provided with a resistance heating element layer 120 on the surface of a glass base 110. The fixing roller 100 is provided with an infrared reflecting layer 140 containing a heat reflecting metal layer on the side, where the resistance heating element layer 120 is not provided, on the inside surface or the outside surface of the glass base 110. The radiation factor of the infrared reflecting layer 140 is smaller than that of the glass base 110.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in, for example, an electrophotographic copying machine, a printer, a facsimile, and the like, and more particularly, to a fixing device having a resistance heating element layer provided on a glass substrate. The present invention relates to improvement of a fixing device.

[0002]

2. Description of the Related Art An electrophotographic copying machine or the like is provided with a fixing device for fixing a toner image transferred onto a sheet such as recording paper or a transfer material as a recording medium onto the sheet. There are various types of fixing devices, and a general heat roller type fixing device includes a fixing roller, also called a heat roller, which thermally melts toner on a sheet, and a pressing roller that presses against the fixing roller to sandwich the sheet. And a pressure roller. The fixing roller is formed in a hollow shape, and a heating element is held on a central axis of the fixing roller by holding means (Japanese Utility Model Laid-Open No. 64-32567, Japanese Patent Laid-Open No. 4-3377).
No. 82).

A general fixing roller in a conventional heat roller fixing device is configured by coating a surface of a metal base made of aluminum or iron with a release material made of PTFE (polytetrafluoroethylene) or the like. . The heating element is formed of, for example, a tubular heating heater such as a halogen lamp, and generates heat when a predetermined voltage is applied. Since the halogen lamp is located at the center axis of the fixing roller, heat generated from the halogen lamp is uniformly radiated to the inner wall of the fixing roller, and the temperature distribution of the outer wall of the fixing roller becomes uniform in the circumferential direction. The outer wall of the fixing roller has a temperature suitable for fixing (for example, 15 ° C.).
(0-200 ° C.).

In this state, the fixing roller and the pressure roller rotate in opposite directions while being pressed against each other, and pinch the sheet to which the toner has adhered. At a pressure contact portion (hereinafter, referred to as a nip portion) between the fixing roller and the pressure roller, the toner on the sheet is melted by the heat of the fixing roller, and is fixed to the sheet by the pressure applied from both rollers. After the toner is fixed, the sheet is conveyed by a paper discharge roller and discharged onto a paper discharge tray as the fixing roller and the pressure roller rotate.

In such a fixing device, the means for transferring heat to the fixing roller is carried out by radiating heat from a halogen lamp disposed inside the fixing roller to the inner surface of the fixing roller. The inner surface of the fixing roller is coated with a black resin-based coating material having a high heat radiation rate to increase the heat radiation rate of the inner surface of the fixing roller to, for example, 0.9 or more. By doing so, the fixing roller is efficiently heated.

However, in a fixing device provided with a heating element composed of a halogen lamp or the like, since heating is basically performed using radiant heat, the heat radiation rate of the inner surface of the fixing roller is increased. Also, it takes a relatively long time for the temperature of the fixing roller to reach a predetermined temperature suitable for fixing after the power is turned on (hereinafter, referred to as “warm-up time”). On the other hand, in order to increase the value of products such as copiers, the size of the apparatus is reduced, and at the same time, energy saving (low power consumption) of the fixing device and improvement in user operability (quick print) are both achieved. Has been noticed and emphasized.

In order to meet this demand, a current-heating type fixing device using a resistance heating element layer has been proposed, in which case the fixing roller generates heat. According to this type of fixing device, the electric-to-heat conversion efficiency is extremely improved, so that the temperature rising speed during warm-up is fast, and the warm-up time can be shortened.

[0008]

A fixing roller having a resistance heating element layer has a configuration in which a resistance heating element layer is laminated on a base, and a release layer is further laminated on the resistance heating element layer. I have. As a material of the substrate, a metal such as aluminum is generally used. In recent years, it has been proposed to use heat-resistant glass known as “Pyrex” (Corning Glass Co., USA). Heat-resistant glass is superior to a base made of metal in this point, since it is not necessary to consider electrical insulation measures.

However, in a fixing roller of a type in which a resistance heating element layer is provided on a glass substrate, the inner surface of the glass is not particularly processed and is in contact with the air layer. For this reason, the infrared rays that have passed through the glass from the resistance heating element layer and reached the inner surface layer of the glass substrate are released into the air as they are, and heat escapes from the inner surface layer of the glass to release heat, resulting in energy loss. I was

In the case of a type that does not employ a heating method using radiant heat to the inner surface of the heat roller, such as a method in which the fixing roller itself generates heat by the resistance heating element layer, if the heat radiation rate of the inner surface of the fixing roller is high, the heat absorption is reduced. The property that heat is easily dissipated without using the property that is easy to use becomes dominant, and not only heating the inside of the fixing roller that does not need to be heated consumes unnecessary energy, but also fixation contrary to the halogen lamp method There is a problem that the speed of raising the temperature of the roller itself is hindered.

The inventor of the present invention has determined that in a fixing roller of a type in which a resistance heating element layer is provided on a glass substrate, energy transmission is lost due to infrared transmission because the substrate is made of glass. Accordingly, the present invention has been completed based on the finding that the fixing roller can be heated with high efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device including a fixing roller of a type in which a resistance heating element layer is provided on a glass substrate. It is an object of the present invention to provide a fixing device that can increase a heating rate, shorten a warm-up time, and consume less energy.

[0013]

According to a first aspect of the present invention, there is provided a fixing device having a fixing roller in which a resistance heating element layer is provided on a surface of a glass substrate.
Of the inner surface and the outer surface of the glass substrate of the fixing roller, on the side where the resistance heating element layer is not provided,
A fixing device provided with an infrared reflecting layer that reflects heat.

According to this structure, the infrared rays reaching the surface layer of the glass substrate are reflected by the infrared reflecting layer toward the resistance heating element layer, so that the transmission of the infrared rays is reduced and the energy loss is reduced as much as possible. I do. As a result, the fixing roller can be heated with high efficiency by effectively utilizing the thermal energy generated in the resistance heating element layer, and the fixing device can reduce the warm-up time and consume less energy.

The invention according to a second aspect is characterized in that the infrared reflecting layer is a metal layer.

According to this structure, in addition to the first aspect of the present invention, since the metal has a higher thermal conductivity than glass, the heat conduction in the longitudinal direction of the fixing roller is improved, and the temperature unevenness in the longitudinal direction of the roller is improved. As a result, the unevenness of the fixing strength along the longitudinal direction of the roller is alleviated.

Further, the invention according to claim 3 is characterized in that the emissivity of the infrared reflecting layer is smaller than the emissivity of the glass substrate.

According to this structure, in addition to the first aspect of the invention, the radiation intensity when heat conducted from the resistance heating element layer to the glass is radiated from the surface layer of the glass substrate is small, and As a result, the heat loss due to heat radiation is reduced, the energy loss is reduced as much as possible, and the fixing roller can be heated with higher efficiency.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a schematic configuration diagram showing a copying machine as an image forming apparatus incorporating a fixing device according to the present invention.

As shown in the figure, the copying machine 10 includes an image scanner unit 11 for reading an original, a signal processing unit 12 for performing signal processing, and an image corresponding to the original image read by the image scanner unit 11 as a recording medium. Sheet 20
And a casing 14 for arranging or storing these units.

In the image scanner section 11, the original placed on the platen glass 15 is a platen cover 1.
6, when an automatic document feeder (not shown) is mounted, an automatic document feeder is attached instead of the platen cover 16. The original on the platen glass 15 is irradiated by the lamp 17, and the light reflected by the original forms an image on a line sensor (CCD) 21 via mirrors 18 a, 18 b, 18 c and a condenser lens 19, and is converted into image information. The signal is sent to the signal processing unit 12. The first slider 2 is driven by driving the scanner motor 22.
Reference numeral 3 denotes a speed V, and the second slider 24 mechanically moves at V / 2 in a direction (sub-scanning direction) perpendicular to the electrical scanning direction (main scanning direction) of the line sensor, and scans the entire original.

The signal processing section 12 electrically processes the signal read by the line sensor 21 and sends the signal to the printer section 13.

The printer unit 13 includes a laser generator 25,
A photoreceptor drum 26 as an image carrier; and a charging roller 27 as a charging device, a developing device 28, a transfer roller 29 as a transfer device, and a sheet 20 around the rotating photoreceptor drum 26. And a cleaning device 31 for removing the residual toner on the photosensitive drum 26 are disposed. The laser generator 25 drives and modulates the semiconductor laser according to the level of the image signal sent from the signal processing unit 12. The laser beam is applied to the photosensitive drum 26 at a position between the charging roller 27 and the developing device 28 via a polygon mirror (not shown), an f-θ lens, a return mirror, and the like. The electrostatic latent image formed on the photosensitive drum 26 is developed by a developing device 28 with toner.

On the other hand, a plurality of sheets 20 are stored in a stacked state in a sheet cassette 35 which is detachably attached to the casing 14. The sheets 20 in the paper feed cassette 35 are separated and fed one by one by a paper feed roller 36, and are directed by a timing roller 37 at a predetermined timing toward a transfer position between the photosensitive drum 26 and the transfer roller 29. Is sent. The image developed on the photosensitive drum 26 is transferred to the sheet 20 by the transfer roller 29. The sheet 20 after the transfer is separated from the photosensitive drum 26, and is conveyed by a conveying belt 39 toward a fixing device 38. The unfixed toner transferred onto the sheet 20 is fixed in the fixing device 38, and the sheet 20 on which the toner has been fixed is discharged to a discharge tray 40. The fixing device 38 of the present embodiment includes a fixing roller 100 of a type in which a resistance heating element layer is provided on a glass substrate, and the configuration will be described later.

When the transfer to the sheet 20 is completed by the transfer roller 29, the photosensitive drum 26 is charged to a negative polarity by a charger (not shown) before the cleaner, the residual toner is removed by the cleaning device 31, and the residual charge is removed by the eraser. Is neutralized. Then, the charging roller 2
7, the latent image is formed by the laser beam, developed by the developing device 28, and the electric charge in the non-developed area is eliminated by the pre-transfer eraser (not shown).

FIG. 2 is a schematic sectional view of the fixing device shown in FIG. 1, and FIG. 3 is a sectional view orthogonal to the axis of the fixing roller.

The fixing device has a fixing roller 100 and a pressure roller 200 that is a backup member that comes into pressure contact with the fixing roller 100. The fixing roller 100 has a support shaft 3 protruding from the side plate member 300 via a bearing 150.
10 rotatably supported. The pressure roller 2
Reference numeral 00 denotes a fixing roller 100 that is rotatably supported by a support unit (not shown) and pressed by a pressing unit (not shown) to press against the fixing roller 100. The fixing roller 100 and the pressure roller 200 are driven to rotate in a sheet feeding direction by a driving unit (not shown).

As shown in FIG. 3, the fixing roller 100 has a pipe-shaped base 110 which functions as a core roller.
And the resistance heating element layer 12
In addition, a release layer 130 is sequentially formed on the outermost layer which is the outer peripheral surface of the resistance heating element layer 120. Substrate 110
Is made of heat-resistant glass such as Pyrex (trade name, Corning Glass Co., USA) or quartz glass. The resistance heating element layer 120 is made of a metal or a conductive resin (for example, a resin in which a conductive substance such as carbon is dispersed).
Or a barium titanate-based ceramic having a positive temperature coefficient. The release layer 130 is made of a heat-resistant resin such as PTFE (polytetrafluoroethylene) or PFA (perfluoroalkoxy fluororesin). Since the base 110 is made of glass, it is not necessary to interpose an insulating layer between the base 110 and the resistance heating element layer 120.

A bearing 150 having a ring shape and including a ball bearing is fitted into both ends of the glass base 110.
The inner peripheral surface of the bearing 150 is fitted on the support shaft 310. As a result, the glass base 110 and thus the fixing roller 100 are supported by the ball bearings of the bearing 150 and rotate smoothly around the support shaft 310. The resistance heating element layer 120 and the release layer 130 rotate integrally with the glass base 110.

The width of the release layer 130 (the length along the longitudinal direction of the glass substrate 110) is set to a size larger than the maximum width of the sheet passing between the fixing roller 100 and the pressure roller 200. . On the other hand, the width of the resistance heating element layer 120 is formed wider than the width of the release layer 130, and the resistance heating element layer 120 protrudes beyond the release layer 130 to both left and right in FIG. Resistance heating element layer 1 protruding from release layer 130
The outer peripheral portions of both ends of the fixing roller 20 are non-sheet passing portions of the fixing roller 100. A pair of left and right conducting portions 160a and 160b provided on the non-sheet passing portion are in contact with both end surfaces of the resistance heating element layer 120, respectively.

The power supply section 160a includes a power supply ring 161a connected to the resistance heating element layer 120, a power supply brush 162a connected to the power supply 400 and slidably in contact with the power supply ring 161a, and a power supply brush 162a directed toward the power supply ring 161a. To the power supply brush 16.
2a.
Similarly, the power supply ring 161b,
It is composed of a power supply brush 162b and a spring 163b.

The pair of power supply rings 161a and 161b
It is made of a conductive copper alloy or the like and has a ring shape. The power supply rings 161a and 161b are provided at the outer peripheral portions of both ends of the resistance heating element layer 120 protruding outward from the release layer 130, with the cylindrical portion of the glass base 110 interposed therebetween.
0 and the resistance heating element layer 1
20. Therefore, the power supply ring 16
1a, 161b and the resistance heating element layer 120 are electrically connected. The power supply rings 161 a and 161 b rotate integrally with the glass base 110 similarly to the resistance heating element layer 120 and the release layer 130. The power supply brushes 162a and 162b are connected to the power supply ring 161 by the springs 163a and 163b.
a, 161b, the power supply ring 161a (16) that rotates integrally with the glass base 110.
The power supply brush 162a (162b) comes into sliding contact with 1b),
The electrical connection at the contact surfaces of both is maintained.

The power supply brushes 162a and 162b are electrically connected to both terminals of a power supply 400 of the copying machine 10 via a switch SW, and the resistance heating element layer 120 is electrically connected to the power supply 400. When the switch SW is turned on, the power supply brush 162a (162
Electric power is supplied from the power supply 400 via b) and the power supply rings 161a and 161b, and the resistance heating element layer 120 itself generates heat due to Joule loss to heat the fixing roller 100. The fixing roller 100 is maintained at a substantially constant temperature (generally, about 150 to 200 ° C.) by controlling power supply based on a temperature detected by, for example, bringing a thermistor into contact with a surface layer.

In particular, the fixing roller 100 according to the first embodiment
In the inner surface and the outer surface of the glass substrate 110, the side on which the resistance heating element layer 120 is not provided, that is, on the inner surface surface layer of the glass substrate 110, an infrared reflection layer 140 that reflects heat is provided. is there. Such infrared reflection layer 1
Reference numeral 40 denotes a thin metal layer made of a metal material such as aluminum, gold, silver, and nickel, and is formed by plating, vapor deposition, thermal spraying, or by applying a paste.

Further, the emissivity of the infrared reflecting layer 140 (=
Emissivity) is smaller than the emissivity of the glass substrate 110. That is, the emissivity of, for example, Pyrex (trade name, Corning Glass Co., USA) forming the base 110 is 0.94 to 0.94 in a temperature range of 260 ° C to 537.8 ° C.
0.75. On the other hand, the infrared reflective layer 1 which is a thin metal layer
The emissivity of, for example, aluminum forming 40 is 600
Temperature range from 200 ° C to 378 ° C even on the surface oxidized at ℃
Is 0.11 to 0.19.

As shown by the arrow in FIG. 4B, in the fixing roller according to the comparative example in which the inner surface layer of the glass substrate 110 is not particularly processed, the glass penetrates the glass from the resistance heating element layer 120. Infrared rays that have reached the inner surface layer of the base 110 are released into the air as they are, resulting in energy loss. On the other hand, as shown in FIG. 2A, the infrared reflective layer 14 is formed on the inner surface of the glass substrate 110.
In the fixing roller 100 according to the first embodiment provided with 0, the infrared rays that have reached the inner surface layer of the glass base 110 are reflected by the infrared reflection layer 140 toward the resistance heating element layer 120, so that the transmission of infrared rays And energy loss is reduced as much as possible.

Further, in the fixing roller according to the first embodiment, since the emissivity of the infrared reflecting layer 140 made of a thin metal layer is smaller than the emissivity of the glass base 110, the resistance heating element layer 120 is made of glass. The radiation intensity when the heat conducted to the base 110 is radiated from the inner surface layer is small, the escape of heat by the heat radiation from the inner surface layer of the glass base 110 is reduced, and the energy loss is reduced as much as possible from this point. I do.

As described above, according to the first embodiment, since the infrared reflecting layer 140, which is a thin metal layer provided on the inner surface of the glass substrate 110, has a high thermal reflectance and a low thermal emissivity, resistance heating is achieved. Unnecessary heat radiation from the inner surface of the body layer 120 or the glass substrate 110 to the inside of the roller is reduced, and the heat energy generated in the resistance heating element layer 120 can be effectively used, and the fixing roller 100 is heated with high efficiency. can do. Therefore, the fixing device 38 is a fixing device that can reduce the heat energy loss during roller heating, increase the temperature rising speed of the fixing roller 100, shorten the warm-up time, and consume less energy.

Further, since metal has a higher thermal conductivity than glass, unevenness in temperature in the longitudinal direction of the fixing roller 100 is reduced, so that unevenness in fixing strength along the longitudinal direction of the roller is alleviated.

Embodiment 2 FIG. 5 is a schematic cross-sectional view of a fixing device according to Embodiment 2 of the present invention, and FIG. 6 is a cross-sectional view orthogonal to the axis of the fixing roller, which is shown in FIGS. Members common to members are given the same reference numerals.

The fixing device according to the second embodiment is the same as the first embodiment in that an electric heating system using a resistance heating element is used, but the resistance heating element layer 120 is formed on the inner peripheral surface of the glass base 110. This is different from the first embodiment in which the resistance heating element layer 120 is formed on the outer peripheral surface of the glass base 110.

In the fixing roller 101 according to the second embodiment, of the inner surface and the outer surface of the glass base 110, the side on which the resistance heating element layer 120 is not provided, that is, the outer surface of the glass base 110 An infrared reflection layer 140 is provided, and a release layer 130 is formed on the outermost layer, which is the outer peripheral surface of the infrared reflection layer 140. Infrared reflective layer 140
Is composed of a thin metal layer as in the first embodiment.

Further, a low heat radiation layer 141 having an emissivity smaller than the emissivity of the resistance heating element layer 120 is formed on the inner peripheral surface side of the resistance heating element layer 120. The infrared reflection layer 140 is included in the low heat radiation layer 141 as long as it has an emissivity smaller than the emissivity of the resistance heating element layer 120. For example, in the case of the resistance heating element layer 120 made of a barium titanate-based ceramic having a positive temperature coefficient, an aluminum-containing paint or the like is applied to the inner surface of the resistance heating element layer 120 via an insulating layer as a low heat emissivity treatment. Is performed. Since the thermal emissivity of the ceramic that is the material of the resistance heating element layer 120 is as high as about 0.91, the thermal emissivity can be suppressed to a relatively low level by performing the above-described processing by a known method.

The bearing 151 serving as a rotation supporting portion of the fixing roller 101 is provided on the outer peripheral surface of the fixing roller 101 and is held in a through hole 320 of the side plate member 300.

The fixing roller 1 according to the second embodiment in which the infrared reflecting layer 140 is provided on the outer surface of the glass substrate 110
In the case of No. 01, since the infrared rays reaching the outer surface layer of the glass base 110 are reflected toward the resistance heating element layer 120 by the infrared reflecting layer 140, the transmission of the infrared rays is reduced, and the energy loss is reduced as much as possible.

Further, the radiation intensity when the heat conducted from the resistance heating element layer 120 to the glass substrate 110 is radiated from the outer surface layer is small, and the heat radiation from the outer surface layer of the glass substrate 110 due to heat radiation is reduced. From this point, the energy loss is reduced as much as possible.

Further, since the low heat radiation layer 141 is provided on the inner peripheral surface side of the resistance heating element layer 120, unnecessary heat radiation toward the inside of the roller is also reduced.

As described above, according to the second embodiment, the infrared reflecting layer 140, which is a thin metal layer provided on the outer surface of the glass substrate 110, has a high heat reflectance and a low heat emissivity. Unnecessary heat radiation from the outer surface of the body layer 120 or the glass substrate 110 to the outside of the roller is reduced, and the low heat radiation layer 141 reduces the heat radiation from the inner surface of the resistance heating element layer 120 or the glass substrate 110 to the inside of the roller. Unnecessary heat radiation is also reduced, and the heat energy generated in the resistance heating element layer 120 can be effectively used, and the fixing roller 101 can be heated with high efficiency. Therefore, the fixing device 38
A fixing device that can reduce the loss of thermal energy at the time of heating the roller, increase the temperature rising speed of the fixing roller 101, shorten the warm-up time, and consume less energy can be obtained. Further, unevenness in fixing strength along the longitudinal direction of the fixing roller 101 is reduced. Moreover, the resistance heating element layer 12
By forming 0 on the inner peripheral surface of the glass substrate 110, it is possible to prevent the resistance heating element layer 120 from deteriorating with time.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the claims. That is, although the embodiment of the type in which self-heating is performed by an energization heating method using a resistance heating element has been described, the present invention can be applied to a fixing roller of a type in which self-heating is performed by an induction heating method.

[0051]

Next, an embodiment according to the present invention will be described. The fixing roller according to the embodiment has a thickness t = 1 mm and a length 320
mm, a resistance heating element layer made of an iron-chromium alloy is formed on the outer peripheral surface of a glass substrate made of heat-resistant glass having an outer diameter of 30 mm, and a PTFE (polytetrafluoroethylene) layer is formed as a release layer on the outermost layer. It is fired to a thickness of about 20 μm. On the inner surface of the glass substrate, an infrared reflecting layer made of an aluminum layer is formed to a thickness of about 0.05 mm by thermal spraying.

As a fixing roller according to a comparative example, a fixing roller in which an aluminum layer was not formed on the inner surface of a glass substrate was used.

The fixing rollers according to the example and the comparative example were incorporated in a fixing device, and a paper passing and fixing test were performed. In the paper passing test, the warm-up time from the start of energization to the resistance heating element layer to the temperature at which it can be fixed (200 ° C.), the average power consumption during standby, and the normal printing (continuous printing at 20 sheets / minute) ) Average power consumption was measured. Further, the temperatures of the paper passing portion and the non-paper passing portion when 50 sheets of paper having a size smaller than the heating width were continuously passed were measured. The resistance heating element layer of the fixing roller was configured to be able to supply a maximum of 900 W of electric power via a power supply ring at the end of the roller, and the energization was controlled while detecting the temperature at the center of the paper passing portion of the fixing roller. The results of the test are shown in Table 1 below.

[0054]

[Table 1]

As is apparent from Table 1, in this embodiment,
Compared to the comparative example, the warm-up time is shorter,
Power consumption was reduced both during standby and during printing. In addition, when the paper having a size smaller than the roller heating width is continuously passed, the temperature rise in the non-paper passing portion is suppressed to be low.

[0056]

As described above, according to the fixing device of the first aspect, the infrared ray is reflected on the inner surface and the outer surface of the glass substrate of the fixing roller on which the resistance heating element layer is not provided. Since the layer is provided, the infrared rays reaching the surface layer of the glass substrate are reflected by the infrared reflecting layer toward the resistance heating element layer, so that the transmission of infrared rays is reduced and energy loss is reduced as much as possible. As a result, the fixing roller can be heated with high efficiency by effectively utilizing the heat energy generated in the resistance heating element layer, and the fixing device which can reduce the warm-up time and consume less energy can be provided.

According to the fixing device of the second aspect, since the infrared reflecting layer is a metal layer, in addition to the effect of the first aspect, the heat conduction in the longitudinal direction of the fixing roller is improved. It is possible to reduce unevenness in fixing strength along the longitudinal direction of the roller.

According to the fixing device of the third aspect, the emissivity of the infrared reflecting layer is smaller than the emissivity of the glass substrate. The radiation intensity when heat transmitted from the glass to the glass substrate is radiated from the surface layer of the glass substrate is small, heat escape from the surface layer of the glass substrate due to heat radiation is reduced, and from this point also energy loss is minimized Therefore, the fixing roller can be more efficiently heated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a copying machine as an image forming apparatus incorporating a fixing device according to the present invention.

FIG. 2 is a schematic sectional view of the fixing device shown in FIG.

FIG. 3 is a cross-sectional view orthogonal to the axis of the fixing roller shown in FIG. 2;

FIG. 4A is an explanatory diagram of an operation of a fixing roller according to Embodiment 1 in which an infrared reflecting layer is provided on an inner surface layer of a glass substrate, and FIG. 4B is an inner surface layer of the glass substrate. FIG. 7 is an explanatory diagram of an operation of a fixing roller according to a comparative example in which processing is not particularly performed.

FIG. 5 is a schematic sectional view of a fixing device according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view orthogonal to the axis of the fixing roller shown in FIG. 5;

[Explanation of symbols]

 38 fixing device 100, 101 fixing roller 110 glass substrate 120 resistive heating element layer 130 release layer 140 infrared reflection layer

Claims (3)

[Claims] 1. A fixing device having a fixing roller in which a resistance heating element layer is provided on a surface of a glass substrate, wherein the resistance heating element layer is formed on an inner surface and an outer surface of the glass substrate of the fixing roller. On the side that is not provided,
A fixing device comprising an infrared reflecting layer that reflects heat. 2. The fixing device according to claim 1, wherein the infrared reflection layer is a metal layer. 3. The fixing device according to claim 1, wherein the emissivity of the infrared reflecting layer is smaller than the emissivity of the glass substrate.