JP2002072757A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which can prevent an extreme temperature rise. SOLUTION: A printer 1 which fixes a toner image on a form P by heating and fusing the image by a heat fixing roller 33 and a pressure roller 35 coming into contact with each other and is equipped with a heat conductive member 71 which receives the heat from a heat source 67 and comes into contact with the heat fixing roller 33 to conduct the heat thereto, a temperature detection part 73 which detects the temperature of the heat conductive member 71, and a temperature control part 74 which controls the heating temperature of the heat source 67; and specific set temperature is inputted to the temperature control part 74 in advance and the temperature control part 74 when detecting temperature higher than set temperature stops supplying the electric power to the heat source 67.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, and the like.

[0002]

2. Description of the Related Art Conventionally, in a fixing apparatus in a field image forming apparatus such as a copying machine, a printer, a facsimile, etc., a toner image of a transfer material passing between a nip between a fixing roller and a pressure roller is heated and melted to thereby form a toner image. Is fixed on the transfer material.

In such a fixing device, a heating method in which a halogen heater is provided on the fixing roller is often used, and a temperature control element such as a thermistor for controlling the temperature is provided on the fixing roller. Abuts through. In addition, an AC power supply circuit in which an AC power supply, a triac (trade name), a temperature fuse, and the like are connected by electric wires supplies power to the halogen heater, so that the temperature of the heating roller rises.

A CPU (Central Processing Unit) which controls the entire image forming apparatus transmits a signal for controlling energization to the halogen heater in accordance with the temperature detected by the thermistor to the triac and drives the triac to set a preset value. Temperature is controlled. That is, the power supply to the halogen heater is cut off only when the temperature of the peripheral surface of the fixing roller exceeds a predetermined limit temperature.

[0005]

On the other hand, in recent years, due to environmental regulations and increasing awareness of environmental protection, various image forming apparatuses cut off the power supply to the heat generating element of the fixing roller of the fixing roller when not in use and supply the power only when necessary. Thus, power consumption has been reduced. In such an energy saving type image forming apparatus, the surface temperature of the fixing roller needs to immediately reach a set temperature during printing (the thermal responsiveness needs to be improved). As a means for satisfying this demand, attempts have been made to reduce the heat capacity of the fixing roller. For this reason, the thickness of the roller core has been reduced, but there is a limit.

[0006] On the other hand, there is an apparatus in which the heat responsive contact is improved by an external radiation type heating device (heating means) for locally heating the surface of the fixing roller from the outside immediately before the nip between the fixing roller and the pressure roller. is there.

However, the above-described heating device is configured to heat the fixing roller when the fixing roller rotates. However, when the control is impossible due to a failure or the like, the heating device may continuously heat while the fixing roller is stationary. There is a problem that the temperature rise becomes remarkable.

Accordingly, an object of the present invention is to provide an image forming apparatus capable of preventing a remarkable temperature rise.

[0009]

According to the first aspect of the present invention, one and the other rotating bodies contacting each other, and one of the rotating bodies is heated from the outside by power supply in synchronization with the rotation of the one rotating body. Heating means for heating a predetermined area of one of the rotating body peripheral surface, one and the other rotating body, while nipping and transporting a transfer material carrying a toner image, In an image forming apparatus in which a toner image is heated and melted and fixed on a transfer material, a heat conducting member that receives heat from a heating unit and conducts heat by contacting one of the rotating members, and a temperature that detects a temperature of the heat conducting member Detecting means, comprising a temperature control means for controlling the heating temperature of the heating means, a predetermined set temperature is input in advance to the temperature control means, when the temperature detecting means detects a temperature higher than the set temperature, The temperature control means is a heating means. Characterized by stopping the supply of power.

According to the first aspect of the present invention, the toner image is heated and melted and fixed to the transfer material by passing the transfer material between the one and the other rotating members. At this time, as one of the rotating bodies is rotating, a heating portion (a predetermined area on the one rotating body peripheral surface) of the one of the rotating bodies by the heating means changes, and the heat is transmitted from the heating means to the heat conducting member. Since heat is transmitted to one of the rotating bodies, the temperature of the heat conducting member is substantially constant and maintains a steady state.

On the other hand, at the time of failure, if heating by the heating means is performed even though one of the rotating bodies is stationary, the heating portion of one of the rotating bodies does not change. Heat is trapped in the heating part and the heat conducting member, and the temperature is about to rise significantly. However, when the temperature detecting means detects that the temperature of the heat conducting member has become higher than the set temperature, the temperature controlling means turns the heating means. Stop supplying power to

As described above, when the temperature of the heat conducting member exceeds the set temperature, heating by the heating means is stopped, so that a remarkable rise in temperature can be prevented and power consumption can be reduced.

According to a second aspect of the present invention, in the first aspect, a contact surface of the heat conductive member with respect to one of the rotating bodies is covered with a fluororesin.

According to the second aspect of the present invention, the first aspect is provided.
In addition to having the same function and effect as the invention described in (1), since the contact surface of the heat conductive member is covered with a fluorocarbon resin having a low coefficient of friction, it is possible to prevent the rotation of one of the rotating bodies from being hindered. The rotation of the rotating body is stabilized.

According to a third aspect of the present invention, there is provided one of the rotating bodies and the other rotating body that are in contact with each other, and heating means for heating one of the rotating bodies from the outside by feeding power in synchronization with the rotation of the one rotating body, The heating means is for heating a predetermined area of the peripheral surface of one rotating body, and one and the other rotating body are transported while nipping and holding a transfer material carrying a toner image.
In an image forming apparatus that heats and fuses a toner image to fix it on a transfer material, a heat conductive member that receives heat from a heating unit, a temperature detecting unit that detects a temperature of the heat conductive member, one of a rotating body and a heat conductive member An intermediate rotator that rotates while being in contact with each other, and a temperature control unit that controls the heating temperature of the heating unit, wherein a predetermined set temperature is input in advance to the temperature control unit, and the temperature detection unit sets the temperature to be lower than the set temperature. The temperature control means stops the power supply to the heating means when detecting a high temperature.

According to the third aspect of the present invention, when the toner image on the transfer material is fixed on the transfer material by being heated and melted by one and the other rotating bodies, the heat of the heat conducting member transfers the heat to the intermediate rotating body. Through one of the rotating bodies. At this time, the heating portion of one of the rotating bodies changes, and the heat from the heating means is transmitted to the rotating one of the rotating bodies via the heat conducting member, so that the temperature of the heat conducting member becomes substantially constant and keeps a steady state.

On the other hand, at the time of failure, when heating by the heating means is performed even though one of the rotating body and the intermediate rotating body is stationary, the temperature of the heat conducting member becomes lower than the set temperature. When the temperature detection unit detects that the temperature has risen, the temperature control unit stops supplying power to the heating unit, so that heating by the heating unit is stopped. Therefore, an effect similar to that of the first aspect is obtained.

According to a fourth aspect of the present invention, in the third aspect of the invention, the intermediate rotator removes residual toner remaining on one of the rotators.

According to the fourth aspect of the present invention, there is provided the third aspect.
In addition to the same operation and effect as the invention described in the above, after fixing the toner image on the transfer material by one and the other rotating body, the intermediate rotating body, by removing the residual toner remaining on the one rotating body, One of the rotating bodies is cleaned. Since the intermediate rotating body cleans one of the rotating bodies, there is no need to separately provide a cleaning member, so that the configuration is simple and the cost can be reduced.

The invention described in claim 5 is the invention according to claims 1 to 4
In the invention described in any one of the above, the heat receiving surface of the heat conductive member is painted black.

According to the fifth aspect of the present invention, there is provided the first aspect.
In addition to the same operation and effect as the invention described in any one of (4) to (4), since the heat receiving surface of the heat conducting member is painted black, the heat absorbing property of the heat conducting member is improved.

The invention described in claim 6 is the invention according to claims 1 to 5
In the invention described in any one of (1) to (4), the temperature detecting means is located upstream of the heating region of the one rotating body in the rotation direction.

According to the sixth aspect of the present invention, there is provided the first aspect.
In addition to the same operation and effect as the invention described in any one of (5) to (5), by arranging the temperature detecting means on the upstream side of the heating region, heat from one of the rotating bodies heated by the heating means can be detected by the temperature detecting means. Since it is difficult to transmit to the means, it is possible to suppress a rise in temperature of the temperature detecting means due to the heating means. Therefore, deterioration of the temperature detecting means due to a rise in temperature can be prevented, and the life of the temperature detecting means can be extended.

According to a seventh aspect of the present invention, a transfer means for transferring a transfer material carrying a toner image on its surface, a guide member for guiding the transfer material transferred by the transfer means, and a guide member for guiding the transfer material. A heating unit for heating the transfer material, wherein the heating unit heats the back surface of the transfer material via a guide member, so that the toner image is heated and melted and is fixed to the transfer material. Temperature control means for transmitting heat from the heating means while guiding the transfer material, temperature detection means for detecting the temperature of the heat conduction member, and temperature control means for controlling the heating temperature of the heating means; A predetermined set temperature is input to the means in advance, and when the temperature detecting means detects a temperature higher than the set temperature, the temperature control means stops supplying power to the heating means.

According to the present invention, when the transfer material is guided by the guide member and the heat conducting member,
The heating unit heats and fuses the toner image on the front surface of the transfer material by heating the back surface of the transfer material via the guide member. At this time, the heat of the heat conducting member and the guide member is being conveyed (moving) by the conveying means.
Since the heat is transmitted to the transfer material, the temperature of the heat conducting member becomes substantially constant and keeps a steady state.

On the other hand, when the transfer material stays on the guide member or the heat conduction member due to poor conveyance, the temperature tends to rise remarkably because heat is trapped in the guide member or the heat conduction member. When the temperature detecting means detects that the temperature of the conductive member has become higher than the set temperature, the temperature control means stops supplying power to the heating means. Therefore, an effect similar to that of the first aspect is obtained.

The invention according to claim 8 is the invention according to claim 7, wherein the guide member is a stainless plate having a slit formed therein, and the stainless plate and the heat conductive member are in contact with each other. And

According to the eighth aspect of the present invention, the same effects as those of the seventh aspect of the invention are obtained, and the stainless steel plate and the heat conductive member are in contact with each other because the stainless steel plate and the heat conductive member are in contact with each other. Since heat is transmitted between the stainless steel plate and the heat conductive member, temperature variations of the stainless steel plate and the heat conducting member can be prevented. Further, since the slit is formed in the stainless steel plate, heat from the heating means is easily transmitted to the transfer material.

According to a ninth aspect of the present invention, in the seventh aspect, the guide member is a transparent glass plate, and the transparent glass plate is in contact with the heat conductive member.

According to the ninth aspect of the present invention, the seventh aspect of the present invention is provided.
As well as the same effect as the invention described in the above, since the transparent glass plate and the heat conductive member are in contact,
Variations in the temperatures of the transparent glass plate and the heat conducting member can be prevented.

According to a tenth aspect of the present invention, in the invention according to any one of the seventh to ninth aspects, the guide surface of the heat conductive member with respect to the transfer material is covered with a fluororesin,
The heat receiving surface of the heat conductive member is painted black.

According to the tenth aspect of the invention, the same operation and effect as those of the seventh to ninth aspects can be obtained, and the guide surface of the heat conductive member is covered with the fluororesin. While the transfer of the transfer material is stable,
Since the heat receiving surface of the heat conducting member is painted black, the heat absorbing property of the heat conducting member is improved.

[0033]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. First, a first embodiment will be described with reference to FIGS. As shown in FIG. 1, a printer (image forming apparatus) 1 has a photoconductor 3 that rotates in the direction of arrow A, and the peripheral surface of the photoconductor 3 is uniformly charged around the photoconductor 3. Charging device 5, a cleaning device 7 for cleaning the peripheral surface of the photoconductor 3, a writing device 9 for forming an electrostatic latent image on the peripheral surface of the photoconductor 3 charged by the laser beam L, Developing sleeve 11 for visualizing the electrostatic latent image of body 3 as a toner image
And a transfer device 15 for transferring the toner image of the photoconductor 3 onto a sheet (transfer material) P.

Further, below the photoconductor 3, a paper feeding device 17 for feeding the paper P between the photoconductor 3 and the transfer device 15 is arranged. The paper supply device 17 has a paper supply cassette 19 that can be attached and detached in the direction of arrow B. The paper P in the paper supply cassette 19 is supported by the middle plate 21 and the arm 23 is pressed by a spring (not shown). The paper is pressed toward the paper feed roller 25 via the paper feed roller 25.

A separation pad 27 is pressed against the paper feed roller 25, and the paper feed roller 25 is rotated by a command from a CPU (not shown) for controlling the entire printer 1 so that the inside of the paper feed cassette 19 is rotated. The top paper of the separation pad 27
As a result, the sheet is conveyed to the registration roller 29 on the downstream side while preventing double feed. The sheet P conveyed to the registration roller 29 is sent out between the photoconductor 3 and the transfer device 15 at a timing synchronized with the image on the photoconductor 3, and the toner image is transferred by the transfer device 15. ing. In the present embodiment, the photoconductor 3 and the transfer device 15 constitute a transport unit, and the paper P that has entered between them is transported toward the fixing device 31.

The paper P on which the toner image has been transferred by the transfer device 15 is conveyed to a fixing device 31 where the heat fixing roller 3
3 and a pressure roller 35 pressed against the position opposite thereto, the toner image is fixed by being heated and pressed.

Thereafter, the sheet P on which the image has been fixed is discharged from the discharge port 39 onto the sheet discharge tray 41 by the sheet discharge roller 37 so as to be placed on the sheet discharge tray 41. The paper discharge tray section 41 has a paper discharge stopper 43, and the paper discharge stopper 43 is provided movably in the direction of arrow C so that it can correspond to various sizes of paper to be discharged. . Further, the cover 42 constituting the sheet discharge tray section 41 can be opened around the rotation support shaft 44.

On the upper front surface of the exterior part 45 of the printer 1,
An operation panel 47, which is an operation unit of the printer 1, protrudes. Further, a power supply 51, a printed board 53 (engine driver board), an electric device such as a controller board 55, a control device, and the like are housed in a case 49 arranged on the left side of the printer 1 in the drawing. A manual paper feeder 57 is rotatably attached to the exterior part 45 by a pin 59.

As shown in FIG. 2, a pressure roller 35 made of an elastic member such as silicon rubber is pressed against the heat fixing roller 33 of the fixing device 31 with a constant pressing force by a spring (not shown). In the present embodiment, a heater 61 is built in the pressure roller 35, and the paper P
Is pressed toward the heat fixing roller 33 while heating the rear surface of the roller. In FIG. 2, reference numeral 34 denotes the heat fixing roller 3.
An entrance guide member for guiding the paper P between the nip between the pressure roller 3 and the pressure roller 35.

The heat fixing roller 33 has a thin pipe made of Al (aluminum) or Fe (iron) as a base material, and has a thickness of about 0.2 mm to 0.3 mm.
The surface layer of the heat fixing roller 33 is a silicon rubber layer. Outside the heating and fixing roller 33, a heating device 63 for heating the surface layer of the heating and fixing roller 33 and a thermostat 65 for measuring a heating temperature of the heating device 63 are provided.

The heating device 63 has a heating source (heating means) 67 such as a halogen heater and a reflecting mirror 69 for directing radiant heat from the heating source 67 to the fixing pressure roller 33. The heating area R on the peripheral surface of the heat fixing roller 33 is heated from the outside in synchronization with the rotation of the pressure roller 35.

The thermostat 65 is provided so as to face the heating device 63, and is located upstream of the heating region R of the heating fixing roller 33 heated by the heating source 67 in the rotation direction of the heating and pressing roller 33. . Since the thermostat 65 is located upstream of the heating region R, the heat from the heating and pressing roller 33 heated by the heating source 67 can be prevented from being transmitted to the thermostat 65. Can be prevented. Therefore, erroneous detection by the thermostat 65 due to a temperature rise can be prevented. Further, the deterioration of the thermostat 65 can be prevented, and the life of the thermostat 65 can be extended.

The thermostat 65 includes a heating source 67.
And a temperature detecting unit (temperature detecting means) 73 for detecting the temperature of the heat conducting member 71 and connected to a temperature control unit 74 having a power supply circuit. Have been. The temperature control section 74 controls the heating temperature of the heating device. This temperature controller 74
When a predetermined set temperature is input in advance, when the temperature detection unit 73 detects a temperature exceeding the set temperature, the power supply to the heating device 63 is stopped to stop the heating by the heating source 67. It has become.

In the present embodiment, the heat conducting member 71 is a plate made of aluminum, one end of which is in contact with the peripheral surface of the heat fixing roller 33, and the other end of which is connected to the temperature detecting section 73. Installed. In the present embodiment,
Although aluminum is used as the heat conducting member 71, the present invention is not limited to this.

The contact surface 71 a of the heat conductive member 71 at one end thereof with respect to the heat fixing roller 33 is covered with a fluororesin which is a low friction material in order to stabilize the rotation of the heat fixing roller 33. The heat-receiving surface 71b of the heat-conducting member 71 is coated with a heat-resistant black paint in order to improve heat absorption.

Next, the operation of the present embodiment will be described based on the above configuration. After turning on the power to the printer 1,
When a print signal is input to the controller board 55, the heat fixing roller 33 and the pressure roller 35 are driven to rotate.
At the same time, the maximum power is supplied to the heating source 67, and the heating source 67 performs heating until the heating and fixing roller 33 reaches a predetermined temperature.

The above-described series of image forming processes are operated in synchronization with the heating state of the fixing heating roller 33, and the developing device 1
3, an unfixed toner image T is formed on the sheet P, and the sheet P is guided to an entrance guide member at the entrance of the fixing device 31. At this point, the heat fixing roller 33 is set to reach a predetermined temperature.

The radiant heat of the heating source 67 locally heats the vicinity of the surface of the silicon rubber layer of the heat fixing roller 33 to increase the temperature of the rubber layer. In this state, the heat fixing roller 33 rotates, and the toner image T of the paper P is heated and melted at a nip portion with the pressure roller 35, and the toner image T is fixed (anchored) on the transfer material. In this process, the heat on the surface of the heat fixing roller 33 locally heated (heating region R) is applied in the heating region R in consideration of the amount of heat dissipated to the inside of the silicone rubber layer.

In the normal operation as described above, the heat conducting member 71 of the thermostat 65 is irradiated with radiant heat from the heating source 67, and this heat is applied to the contact portion 7 of the heat conducting member 71.
Since the heat is taken away by the rotating peripheral surface of the heat fixing roller 33 via 1a, the temperature rise value becomes substantially constant, and the steady state is maintained.

On the other hand, in the event of a failure, the rotation of the heating source 67 and the heating and fixing roller 33 may become uncontrollable. In this case, if the heating source 67 is continuously lit while the heating and fixing roller 33 is stationary. , The temperature rise becomes large. However, in the present embodiment, in such a failure mode, the heat balance of the heat conducting member 71 changes.

That is, the heat of the heat conducting member 71 escapes to the stationary heating and fixing roller 33, but this heat continues to escape to the same area on the surface of the heating and fixing roller 33, so that the temperature of this area increases. Since heat hardly escapes (is hardly transmitted) from the heat conductive member 71 to the heat fixing roller 33, heat is stored in the heat conductive member 71, and the heat is fixed to the heating region R because the heat fixing roller 33 is stationary. I will be muffled.

Therefore, when the temperature of the heat conducting member 71 becomes higher than the steady state and the temperature detecting section 73 detects that the temperature of the heat conducting member 71 exceeds the set temperature, the temperature control section 74 supplies power to the heating device 63. Is shut off, and the heating by the heating source 67 stops. As described above, when the temperature of the heat conducting member 71 exceeds the set temperature, heating by the heating source 67 is stopped, so that a remarkable rise in temperature can be prevented and power consumption can be reduced. Further, since a remarkable temperature rise can be prevented, it is possible to prevent the surface layer of the heat fixing roller 67 from melting.

Next, another embodiment will be described. In the description, the same parts as those described above are denoted by the same reference numerals, and the description thereof will be omitted.

In the second embodiment, as shown in FIG.
An endless belt member (intermediate rotating body) 75 that contacts one end of the heat conductive member 71 and the peripheral surface of the heat fixing roller 33 to release the heat of the heat conductive member 71 to the heat fixing roller 33; The difference from the first embodiment is that a wiper blade 77 for cleaning the peripheral surface is provided.

The belt member 71 is made of a heat-resistant rubber material having a larger surface energy than the surface layer of the heat fixing roller 33. The belt member 71 removes residual toner remaining on the heat fixing roller 33 while being driven by the driving roller 75. The wiper blade 77 collects the remaining toner transferred from the heat fixing roller 33 to the belt member 71 while scraping it off.

The heat of the heat conductive member 71 is
Since the belt member 71 that is released to the outside also cleans the heat fixing roller 33, there is no need to separately provide a cleaning member for cleaning the heat fixing roller 33, so that the configuration is simple and the cost can be reduced.

FIG. 4 shows a fixing device 3 according to the third embodiment.
FIG. 3 is an enlarged view showing the vicinity of 1; In the third embodiment, as shown in FIG. 4, a sheet P conveyed by the photoconductor 3 and the transfer device 15 is interposed between the fixing device 31 and the photoconductor 3 and the transfer device 15 as the conveyance unit. It has an upstream guide member 77 for guiding, a downstream guide member 79, and a heating device 81 for applying radiant heat toward the downstream guide member 79, and the thermostat 65 includes the heating device 81, the upstream guide member 77, It is provided between. Further, in the present embodiment, the heater 36 is built in the heat fixing roller 33.

The heating device 81 has a heating source 83 for heating with radiant heat by far infrared rays, and a reflecting mirror 85 for directing the radiant heat from the heat source 83 to the fixing pressure roller 33.
The heating source 83 rises and lights up for a predetermined time in synchronization with the operation of the image forming process of the printer 1, and the downstream guide member 7
9, the back surface of the paper P is heated.
Further, the heating source 83 is turned off at the timing when the rear end of the sheet P has passed through the downstream guide member 79.

In the present embodiment, the downstream guide member 79
Is a stainless steel plate, and a heat conductive member 71 is in close contact with the upstream end of the downstream guide member 79. Since the downstream guide member 79 and the heat conducting member 71 are in close contact with each other, radiant heat from the heating source 83 (see the broken arrow in FIG. 4) is easily transmitted to the heat conducting member 71 (see the solid arrow in FIG. 4). Therefore, the heat radiation and heat collection of the downstream side guide member 79 are hardly influenced by the paper passing cycle. Further, since heat is easily transmitted between the heat conductive member 71 and the downstream guide member 79, the heat conductive member 71 and the downstream guide member 79 are easily transferred.
Temperature variation can be prevented.

As shown in FIG. 5, a large number of slits 79a are formed in the downstream guide member 79 by an etching method or the like. Therefore, the radiant heat from the heating source 83 is easily transmitted to the sheet P through the slit 79a. In the present embodiment, the downstream guide member 79 is made of a stainless steel plate, but is not limited to this. For example, a transparent glass plate may be used.

On the other hand, in the present embodiment, as shown in FIGS.
The guide surface 71c is covered with a fluororesin to stabilize the conveyance of the paper P. Further, the heat receiving surface 71b of the heat conducting member 71 is painted black as in the first embodiment.

Next, the operation of the present embodiment will be described based on the above configuration. As in the first embodiment, when a print signal is input to the controller board 55, the maximum power is supplied to the heater 36 of the heat fixing roller 33, and heating is performed to a predetermined temperature. In synchronization with this heating state, the above-described series of image forming processes is operated, and after the transfer device 15 forms the unfixed toner image T on the sheet P, the sheet P is transferred to the fixing device 31 by the photoconductor 3 and the transfer device 15. Conveyed toward. At this point, the heat fixing roller 33 is set so as to reach a predetermined temperature.

The sheet P carrying the unfixed toner image T is guided to the downstream guide member 79 via the upstream guide member 77. At this time, the radiant heat of the heating source 83 is transmitted to the sheet P via the downstream guide member 79, the unfixed toner image T is melted, and the sheet P is guided to the entrance guide member provided at the entrance of the fixing device 31. Is pressed by the heat fixing roller 33 and the pressure roller 35 so that the molten toner
And the surface thereof becomes glossy according to the surface properties of the heat fixing roller 33.

In the normal operation as described above, the thermostat 65 is irradiated with the radiant heat from the heating source 67 and, at the same time, passes through the guide surface 71c of the heat conducting member 71 while making contact with the sheet P, so that the thermostat 65 By being deprived of heat, the temperature rises to a substantially constant value and maintains a steady state.

On the other hand, when the heating source 83 becomes uncontrollable and lights continuously without synchronizing with the passage of the sheet P at the time of a failure, the sheet P may not be transported due to a conveyance failure.
When it stays on the heat transfer member 71 or the heat transfer member 71, the heat hardly escapes to the paper P from the downstream side guide member 79 or the heat conduction member 71, so that the heat is stored in the downstream side guide member 79 or the heat conduction member 71, The temperature of the heat conducting member 71 becomes higher than in a steady state. When the temperature detecting unit 73 detects that the temperature of the heat conducting member 71 exceeds the set temperature, the power supply to the heating device 63 is cut off by the temperature control unit 74 and the heating by the heating source 83 is stopped.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, the heat fixing roller 33 is used as one of the rotating bodies, but the present invention is not limited to this, and a fixing belt stretched around the roller may be used.
Even in this case, the same operation and effect can be obtained.

In the second embodiment, the endless belt is used as the intermediate rotating body, but a roller may be used as the intermediate rotating body.

Although the present invention has been applied to a printer, the same effect can be obtained by applying it to an image forming apparatus such as a copying machine and a facsimile.

[0069]

According to the first aspect of the present invention, when the temperature of the heat conducting member exceeds the set temperature, the heating by the heating means is stopped, so that a remarkable temperature rise can be prevented and the power consumption can be reduced. can do.

According to the second aspect of the present invention, the same effect as that of the first aspect of the invention is obtained, and the contact surface of the heat conductive member is covered with a fluororesin having a low friction coefficient. Since the rotation of the rotating body can be prevented from being hindered, the rotation of one of the rotating bodies is stabilized.

According to the third aspect of the present invention, even when the intermediate rotating body is provided between the heat conducting member and one of the rotating bodies, the temperature is remarkably increased as in the first aspect of the invention. The rise can be prevented, and the power consumption can be reduced.

According to the fourth aspect of the invention, the same effect as that of the third aspect of the invention is obtained, and since the intermediate rotating body cleans one of the rotating bodies, it is not necessary to separately provide a cleaning member. The structure is simple and the cost can be reduced.

According to the fifth aspect of the present invention, the same effects as those of the first to fourth aspects can be obtained, and the heat receiving surface of the heat conductive member is painted black.
The heat absorption of the heat conducting member is improved.

According to the sixth aspect of the present invention, the same effects as those of the first to fifth aspects are obtained, and the heat from one of the rotating bodies heated by the heating means is transmitted to the temperature detecting means. Since the transmission is difficult, the temperature rise of the temperature detecting means by the heating means can be suppressed, the deterioration of the temperature detecting means due to the temperature rise can be prevented, and the life of the temperature detecting means can be extended.

According to the seventh aspect of the present invention, even if the heat conducting member is configured to transmit heat to the transfer material, a remarkable rise in temperature can be prevented as in the first aspect of the present invention. Power consumption can be reduced.

According to the eighth aspect of the present invention, the same effect as that of the seventh aspect of the invention is obtained, and the temperature of the stainless steel plate and the heat conductive member is increased by the contact between the stainless steel plate and the heat conductive member. Can be prevented. Further, since the slit is formed in the stainless steel plate, heat from the heating means is easily transmitted to the transfer material.

According to the ninth aspect of the present invention, the same effect as that of the seventh aspect of the invention is obtained, and the transparent glass plate and the heat conductive member are in contact with each other. Temperature variations can be prevented.

According to the tenth aspect, the same effects as those of the seventh to ninth aspects can be obtained, and the guide surface of the heat conductive member is covered with the fluororesin. Is stabilized, and the heat receiving surface of the heat conducting member is painted black, so that the heat absorbing property of the heat conducting member is improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing an image forming apparatus according to the present invention.

FIG. 2 is an enlarged view showing the vicinity of a fixing device.

FIG. 3 is an enlarged view showing the vicinity of a fixing device according to a second embodiment.

FIG. 4 is an enlarged cross-sectional view showing the vicinity of a fixing device according to a third embodiment.

FIG. 5 is an enlarged sectional view showing a guide member of FIG. 4;

6A is a diagram of the heat conduction member of FIG. 4 as viewed from below, and FIG. 6B is a diagram of the heat conduction member of FIG. 4 as viewed from above.

[Explanation of symbols]

 1 Printer (Image Forming Apparatus) 3 Photoconductor (Conveying Means) 15 Transfer Apparatus (Conveying Means) 33 Heat Fixing Roller (One Rotating Body) 35 Pressure Roller (The Other Rotating Body) 67, 83 Heat Source (Heating Means) 71 Thermal Conductive Member 73 Temperature Detector (Temperature Detector) 74 Temperature Controller (Temperature Controller) 75 Cleaning Belt (Intermediate Rotating Body) 79 Downstream Guide Member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Jun Yura 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2H032 BA17 BA19 BA21 2H033 AA08 AA24 BA08 BA12 BA26 BA31 BA32 BA48 BA55 BA57 BB01 BB18 BB23 BB28 CA07 CA27 CA45

Claims (10)

[Claims] 1. One and the other rotating bodies contacting each other, and heating means for heating one of the rotating bodies from the outside by power supply in synchronization with the rotation of the one rotating body, wherein the heating means is one of the rotating bodies Heats a predetermined area of the peripheral surface,
In an image forming apparatus in which one and the other rotating bodies sandwich and transport a transfer material carrying a toner image, the toner image is heated and melted to be fixed to the transfer material. A heat conductive member that contacts and transfers heat to the rotating body, a temperature detecting unit that detects a temperature of the heat conductive member, and a temperature control unit that controls a heating temperature of the heating unit. An image forming apparatus, wherein a set temperature is input in advance, and when the temperature detecting means detects a temperature higher than the set temperature, the temperature control means stops supplying power to the heating means. 2. The image forming apparatus according to claim 1, wherein a contact surface of the heat conductive member with respect to one of the rotating bodies is covered with a fluororesin. 3. One and the other rotating bodies that are in contact with each other, and heating means for heating one of the rotating bodies from the outside by feeding power in synchronization with the rotation of the one rotating body, wherein the heating means is the one rotating body. Heats a predetermined area of the peripheral surface,
In an image forming apparatus in which one and the other rotating members hold and transfer a transfer material carrying a toner image while nipping the transfer material, the toner image is heated and melted and fixed to the transfer material. A member, a temperature detecting means for detecting a temperature of the heat conducting member, an intermediate rotating body which rotates while being in contact with one of the rotating body and the heat conducting member, and a temperature control means for controlling a heating temperature of the heating means. , A predetermined set temperature is previously input to the temperature control means,
An image forming apparatus, wherein when the temperature detecting means detects a temperature higher than the set temperature, the temperature control means stops supplying power to the heating means. 4. The image forming apparatus according to claim 3, wherein the intermediate rotator removes residual toner remaining on one of the rotators. 5. The image forming apparatus according to claim 1, wherein the heat receiving surface of the heat conductive member is painted black. 6. The image forming apparatus according to claim 1, wherein the temperature detecting unit is located on the upstream side in the rotation direction of the heating area of the one rotating body. 7. A conveying means for conveying a transfer material having a toner image carried on a surface thereof, a guide member for guiding the transfer material conveyed by the conveying means, and a heating means for heating the transfer material guided by the guide member. In an image forming apparatus in which a heating unit heats and fuses the toner image by fixing the back surface of the transfer material via a guide member, the heating unit heats the transfer material while guiding the transferred transfer material. A heat conducting member for transmitting heat from the means, a temperature detecting means for detecting a temperature of the heat conducting member, and a temperature control means for controlling a heating temperature of the heating means, wherein the temperature control means has a predetermined set temperature. Is input in advance, and when the temperature detection unit detects a temperature higher than the set temperature, the temperature control unit stops supplying power to the heating unit. 8. The image forming apparatus according to claim 7, wherein the guide member is a stainless plate having a slit formed therein, and the stainless plate and the heat conductive member are in contact with each other. 9. The image forming apparatus according to claim 7, wherein the guide member is a transparent glass plate, and the transparent glass plate is in contact with the heat conductive member. 10. The heat conductive member guide surface for the transfer material is covered with a fluororesin, and the heat conductive member heat receiving surface is painted black.
An image forming apparatus according to any one of claims 1 to 9.