JPH11161097A - Fixing device, temp. controlling means, and image forming device provided with them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of setting and maintaining a nip section at the temp. area suitable to fixation, during the time while the fixing operation is performed. SOLUTION: This device is provided with the controlling circuit 31 controlling a first heating material driving circuit 32 driving the first heating material 18 for heating recording paper, and the second heating material driving circuit 33 driving the second heating material 28 heating pressure means, the temp. sensor 26 detecting the temp. of the first heating material 18, and the temp. sensor 29 detecting the temp. of the pressure means on the upstream side of the nip section in the recording paper transporting direction. Then, during fixation, the controlling circuit 31 is allowed to control the first heating material driving circuit 32 based on the detection of temp. sensors 26 and 29, in order that the first heating material 18 is allowed to heat on correcting the heating operation the second heating material 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a first heating means for heating a sheet-like transfer material carrying an unfixed image via an endless belt-like fixing member, and press-contacting the fixing member via the transfer material. A fixing device, a temperature control means, and a cylindrical or substantially cylindrical or columnar or substantially cylindrical rotatable pressurizing body, and a first temperature detecting body for detecting a temperature of the first heating means. The present invention relates to an image forming apparatus including these.

[0002]

2. Description of the Related Art As a conventional image forming apparatus, a first heating means for heating one surface of a sheet-shaped transfer material, a first heating driving means for heating and driving the first heating means, A first temperature detector for detecting the temperature of the first heating means, a film serving as a fixing body which runs endlessly slidably on the first heating means, and slides the film on the first heating means. Driving means for traveling in a state, a pressurizing body pressed against the film so as to face the first heating means via the film,
2. Description of the Related Art An image forming apparatus including a control unit that controls heating driving of the first heating unit by the first heating driving unit is known.

[0003]

However, in the above-described image forming apparatus, since the pressure member is at the ambient temperature, the pressure member is not heated during the fixing operation. Since the heat is removed from the first heating means via the film each time it faces the means, the nip formed between the film and the pressure body pressed against each other reaches a predetermined target temperature. It needed some time.

[0004] In particular, when the surroundings of the pressurizing means are at a cold ambient temperature, the degree of absorption of heat from the first heating means by the pressurizing means becomes remarkable, and the nip portion is short-lived. Could not reach the predetermined target temperature.

Accordingly, the present invention provides a fixing device capable of raising and maintaining a nip portion in a temperature range suitable for fixing during a fixing process, or an image forming apparatus provided with the fixing device. With the goal.

[0006]

According to the present application, the above object is achieved by a first heating means for heating a sheet-like transfer material carrying an unfixed image via an endless belt-shaped fixing member; A cylindrical or substantially cylindrical or cylindrical or substantially cylindrical rotatable pressurizing member pressed into contact with the fixing member via the transfer material;
In a fixing device including a first temperature detector for detecting the temperature of the first heating unit, a second heating unit for heating the pressure unit, and a second temperature detector for detecting the temperature of the pressure unit A second temperature detecting member is disposed upstream from a nip portion formed between the fixing member and the pressing member pressed against each other with respect to a rotation direction of the pressing member, and a fixing process is performed. During heating, both heating means perform a heating operation in accordance with the detection results of both temperature detectors so that the nip portion is maintained at the target temperature for the fixing process. This is achieved by the first invention in which the second heating means is set to perform the heating operation in accordance with the detection result of the second temperature detector so that the target temperature is maintained at the target temperature.

Further, according to the present application, the above object is achieved in the first invention according to the present application, wherein the first heating means is provided with a heating resistor on one surface of a thin substrate mainly composed of ceramics. The present invention is also achieved by the second invention in which the ceramic heater is a ceramic heater in which the first temperature detecting body is disposed in contact with or close to the other surface while the body is coated.

[0008] Further, according to the present application, the above object is achieved in the first invention or the second invention according to the present application, wherein the second heating means includes a hollow portion of the pressurizing member for the pressurizing member. This is also achieved by the third invention in which the halogen heater is arranged along the axial direction.

Further, according to the present application, the above object is to provide a temperature control means for controlling the temperature of a fixing member and a pressure member provided in the fixing device according to the first invention of the present application, A first heating drive unit that drives one heating unit, a second heating drive unit that drives a second heating unit, and a control unit that controls the driving of each heating unit by both heating drive units. During the fixing process, the control unit controls both the heating units to perform the heating operation in accordance with the detection results of the two temperature detectors so that the nip portion is maintained at the target temperature for the fixing process. The heating driving unit is controlled, and during the fixing standby, the second heating unit performs the heating operation in accordance with the detection result of the second temperature detector so that the pressurized body is maintained at the target temperature for the fixing standby. The fifth is that the second heating drive means is adapted to be controlled It is also achieved by Akira.

[0010] Further, according to the present application, the above object is achieved in the fourth invention according to the present application, wherein the first heating means includes a heating resistor provided on one surface of a thin substrate mainly composed of ceramics. The present invention is also achieved by the fifth invention in which the ceramic heater is a ceramic heater in which the first temperature detecting body is disposed in contact with or in proximity to the other surface while the body is coated.

According to the present application, the above object is achieved in the fourth invention or the fifth invention according to the present application, wherein the second heating means is the second heating means, and the second heating means is a hollow body of the pressurizing body. The present invention is also achieved by the sixth invention in which the halogen heater is disposed along the axial direction of the pressurizing member at the portion.

Further, according to the present application, the above object can be attained by a seventh invention in which the fixing device according to the first invention and the temperature control means according to the fourth invention are provided. Is done.

Further, according to the present application, the above object is achieved in the seventh invention according to the present application, wherein the first heating means is provided with a heating resistor on one surface of a thin substrate mainly composed of ceramics. The present invention is achieved by an eighth invention in which the ceramic heater is a ceramic heater in which a first temperature detecting member is disposed in contact with or in proximity to the other surface while the body is coated.

Further, according to the present application, the above object is achieved according to the seventh invention or the eighth invention according to the present application, in which the second heating means comprises a hollow portion of the pressurizing body, The invention is also achieved by the ninth invention in which the halogen heater is arranged along the axial direction.

That is, in the first invention according to the present application, during the fixing process, both the nip portions are maintained in accordance with the detection results of the two temperature detectors so as to be maintained at the target temperature for the fixing process. The heating means performs a heating operation, and during the fixing standby, the second heating means performs the heating operation in accordance with the detection result of the second temperature detector so that the pressurized body is maintained at the target temperature for the fixing standby. I do.

In the second invention according to the present application,
A fixing member is formed by a ceramic heater in which a heating resistor is coated on one surface of a thin plate-shaped substrate mainly composed of ceramics and a first temperature detector is arranged in contact with or close to the other surface. The transfer material carrying the unfixed image is heated via the.

Further, in the third invention according to the present application, the pressing body is heated by the halogen heater disposed along the axial direction of the pressing body in the hollow portion of the pressing body.

Further, in the fourth invention according to the present application,
During the fixing process, both the heating driving units perform the heating operation in accordance with the detection results of the two temperature detectors so that the nip portion is maintained at the target temperature for the fixing process. During the fixing standby, the second heating means performs the heating operation in accordance with the detection result of the second temperature detector so that the pressure member is maintained at the target temperature for the fixing standby. Is controlled.

Further, in the fifth invention according to the present application, a heating resistor is coated on one surface of a thin plate composed mainly of ceramics, and is contacted with or contacted with the other surface. A transfer material carrying an unfixed image is heated via a fixing member by a ceramic heater in which a first temperature detecting member is disposed in proximity.

In the sixth invention according to the present application,
The pressing body is heated by a halogen heater arranged in the hollow portion of the pressing body along the axis direction of the pressing body.

Further, in the seventh invention according to the present application, the nip portion is maintained at the target temperature for the fixing process during the fixing process by the control means of the temperature control means provided in the image forming apparatus. Both heating driving means are controlled so that both heating means perform the heating operation in accordance with the detection results of the two temperature sensing bodies, and during the fixing standby, the pressure body reaches the target temperature for the fixing standby. The second heating drive unit is controlled so that the second heating unit performs the heating operation in accordance with the detection result of the second temperature detector so as to be maintained.

In the eighth invention according to the present application,
A fixing member is formed by a ceramic heater in which a heating resistor is coated on one surface of a thin plate-shaped substrate mainly composed of ceramics and a first temperature detector is arranged in contact with or close to the other surface. The transfer material carrying the unfixed image is heated via the.

Further, in the ninth invention according to the present application, the pressurizing body is heated by the halogen heater disposed in the hollow portion of the pressurizing body along the axial direction of the pressurizing body.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view showing a schematic configuration of the image forming apparatus 1. As shown in FIG.

The main body 2 of the image forming apparatus 1 has a pressure plate 3
A platen glass 4, an illumination lamp 5, an optical system 6,
Photosensitive drum 7, charging device 8, developing device 9, transfer device 10
, Separator 11, transport belt 12, fixing device 13
, Paper feed cassettes 14 and 15, and a paper discharge roller 16.

Original platen glass 4 provided in main body 2
When copying an original (not shown), the original is spread to a predetermined position on the original platen glass 4, and then the original is pressed to a predetermined position on the original platen glass 4 by the pressure plate 3. .

The illumination lamp 5 provided on the main body 2 is
It is supported by the main body 2 so as to be movable in a direction perpendicular to the plane of the paper of FIG.

When the original is copied, the illumination lamp 5
After scanning the image information on the original via the platen glass 4, the surface of the photosensitive drum 7 is irradiated with light based on the image information, for example, a laser (not shown) via the optical system 6. Has become.

The photosensitive drum 7 provided in the main body 2 is
It is rotatably supported by the main body 2 and rotates at a predetermined peripheral speed set by a photosensitive drum driving means (not shown) provided in the main body 2.

The photosensitive drum 7 is also charged to a predetermined potential or the like by a charger 8, and a charged area on the surface of the photosensitive drum 7 emits light based on image information of a document. When irradiated from the illumination lamp 5 through the optical system 6, the light is exposed to form an electrostatic latent image.

When the developing device 9 provided in the main body 2 faces a latent image area on the surface of the photosensitive drum 7,
A developer, for example, a toner made of a resin softened and melted by heat is applied to the electrostatic latent image. Therefore, the electrostatic latent image is developed by applying the developer from the developing device 9 to become a visible image.

When the transfer unit 10 provided in the main body 2 faces the visible image area on the surface of the photosensitive drum 7, the transfer unit 10 transfers the visual image to the paper feed cassette 14 or the paper feed cassette 15
Recording sheet (not shown) as a sheet-like transfer material conveyed at a predetermined timing or the like from any one of them
Then, the image is transferred by, for example, corona discharge.

The separator 11 provided in the main body 2 separates the recording paper after the transfer by the transfer unit 10 from the photosensitive drum 7 and is separated from the photosensitive drum 7 by the separator 11. The recording paper is transported to the transport belt 12.
Is transported to the fixing device 13 at a predetermined transport speed.

The fixing device 13 provided in the main body 2 is
When the recording paper carrying the unfixed developed image is separated and conveyed from the photosensitive drum 7 by the separator 11 and the conveyor belt 12, the unfixed developed image is fixed on the recording paper by heat. ing.

The paper discharge roller 16 provided in the main body 2
The recording paper is rotatably supported by the main body 2 and discharges the recording paper fixed by the fixing device 13 to the outside of the main body 2.

Next, the fixing device 13 provided in the image forming apparatus 1 will be described with reference to FIG.

FIG. 2 is a schematic sectional view showing a schematic configuration of the fixing device 13.

The main body 17 of the fixing device 13 (see FIG. 1)
A first heating member 18 as a first heating means, a driving roller 19 for driving an endless belt-shaped film 22 as a fixing member, driven rollers 20 and 21, and a pressure roller 23 as a pressing member. Is provided.

The first heating element 18 provided in the main body 17
Is an alumina substrate 24 fixed to the main body 17,
Resistive material 2 coated on the first surface, which is one surface of the alumina substrate 24, along the longitudinal direction of the alumina substrate 24
5, which is a so-called low-heat-capacity linear heating element. When the resistance material 25 is energized from both ends in the longitudinal direction of the resistance material 25, it generates heat by Joule heat.

On a second surface, which is the other surface of the alumina substrate 24 provided on the first heating member 18, a temperature sensor 26 serving as a first temperature detecting member for detecting the temperature of the first heating member 18 is provided. Is attached.

The driving roller 19 provided on the main body 17
The driven rollers 20 and 21 are rotatably supported at predetermined positions on the main body 17.
9 rotates at a predetermined peripheral speed by a motor 27 (see FIG. 3) provided in the image forming apparatus 1.

The film 22 provided on the main body 17
Is a so-called endless film, which is given a predetermined tension by the driving roller 19 and the driven rollers 20 and 21 so as to run endlessly in the direction of arrow V while sliding on the first surface, and Arrow V by roller 19
Driven in the direction.

The pressure roller 23 provided in the main body 17
Is rotatably supported by the main body 17, and is configured to hold the film 22 between the first surface and transport the film 22 in the direction of the arrow V.

The pressure roller 23 incorporates a second heating element 28 as a second heating means, for example, a halogen heater (having a driving power of about 200 to 400 W).

The second heating element 28 generates heat by Joule heat by a predetermined power supply which is performed at the same time as or after a predetermined time when the image forming apparatus 1 is started up, and reduces the surface temperature of the pressure roller 23. For example, it is set to 100 ° C.

Therefore, when the recording paper P carrying the unfixed visible image reaches the nip formed between the first surface and the pressure roller 23, the first heating member 18 and the second heating member Body 28
As a result, the unfixed visible image is melted and fixed.

Further, around the pressure roller 23, upstream of the nip portion between the nip portion and a portion of the outer peripheral surface of the pressure roller opposite to the nip portion in the running direction of the film 22. A temperature sensor 29 as a second temperature detecting means for detecting the surface temperature of the pressure roller 23, for example, a thermistor is provided.

Next, various controls of the fixing device 13 by the temperature control means 30 provided in the image forming apparatus 1 will be described with reference to FIG.

FIG. 3 is a block diagram showing a schematic configuration of the temperature control means 30 for controlling the fixing device 13.

The temperature control means 30 includes a control circuit 31 as heating element driving control means, a first heating element driving circuit 32 as first heating driving means for heating and driving the first heating element 18, A second heating element driving circuit 33 serving as second heating driving means for heating and driving the two heating elements 28;
And a motor drive circuit 34 for driving the motor 7.

The control circuit 31 provided in the temperature control means 30 includes a temperature sensor 26, 29, a first heating element driving circuit 32, a second heating element driving circuit 33, and a motor driving circuit 34. Connected to

The control circuit 31 includes the first heating element 1
8. A memory 35 in which a target temperature of each of the pressure rollers 23 and a peripheral speed of the motor 27 required for the first heating member 18 to reach a predetermined target temperature and the like are stored in advance.

Further, the control circuit 31 is started when the image forming apparatus 1 is started up, and transmits a heating drive command signal described below to the second heating element drive circuit 33.

Here, the heating drive command signal is used to set the heating temperature of the first heating member 18 to a predetermined target temperature or the surface temperature of the pressure roller 23 to a predetermined target temperature. This signal instructs the first heating element driving circuit 32 to drive the heating element 18 or the second heating element driving circuit 33 to drive the second heating element 28.

The control circuit 31 outputs a detection signal from the temperature sensor 29 while the fixing operation is not being performed.
A predetermined trigger pulse is turned on and off to the second heating element driving circuit 33 by comparing the temperature with a predetermined target temperature of the pressure roller 23 recorded in the memory 35.

Further, the control circuit 31 operates at the same time as the start of the copying operation by the image forming apparatus 1 or after a predetermined time.
A predetermined motor drive command signal described below is transmitted to the motor drive circuit 34.

Here, the motor drive command signal is a signal for instructing the motor drive circuit 34 to drive the motor 27 at a predetermined peripheral speed.

The control circuit 31 transmits a heating drive command signal to the first heating element driving circuit 32 a predetermined time before the start of the fixing operation.

Further, the control circuit 31 controls the detection signal from the temperature sensor 26 and the first heating data recorded in the memory 35 so that the nip reaches a predetermined temperature during the fixing operation. In addition to comparing a predetermined target temperature of the body 18 with a predetermined trigger pulse based on a difference between a detection signal from the temperature sensor 29 and a target temperature of the pressure roller 23 recorded in the memory 35, The heating element drive circuit 32 is turned ON and OFF.

At the same time, the control circuit 31 generates a predetermined trigger pulse based on the temperature sensor 29 so that the pressure roller 23 is maintained at the temperature detected by the temperature sensor 29. O to heating element drive circuit 33
N, it is also turned off.

That is, the control circuit 31 determines whether the temperature detected by the temperature sensor 29 matches the predetermined target temperature of the pressure roller 23 while the fixing operation is being performed or not. The first heating element drive circuit 32 is controlled in the following manner in three cases, that is, when the temperature is high and when the detected temperature is lower than the target temperature.

When the temperature detected by the temperature sensor 29 matches the predetermined target temperature of the pressure roller 23, the detection signal transmitted from the temperature sensor 29 to the control circuit 31 Since the target temperature has been reached, the control circuit 31 sends the detection signal from the temperature sensor 26 and the memory 3 so that the first heating element 18 reaches the target temperature.
5 is set to a predetermined temperature by comparing a predetermined target temperature of the first heating element 18 recorded in 5 with a predetermined trigger pulse to the first heating element drive circuit 32 to turn ON and OFF. I do.

When the temperature detected by the temperature sensor 29 is higher than a predetermined target temperature of the pressure roller 23, the control circuit 31 determines whether the temperature of the pressure roller 23 has been detected by the temperature sensor 29. A predetermined trigger pulse is turned on and off to the second heating element drive circuit 33 so as to be maintained.

It is assumed that the control circuit 31 has the temperature sensor 2
6 is compared with a predetermined target temperature of the first heating element 18 recorded in the memory 35, and when the first heating element 18 reaches the target temperature, the nip portion is Since excessive heat is supplied by the heating operation of the two heating elements 28, the temperature is set higher than the predetermined temperature.

In order to supply an appropriate amount of heat from the first heating element 18 and the second heating element 28 to the nip, the amount of heat Q1 to be supplied from the first heating element 18 to the nip is required. Is an amount ΔQ−δQ obtained by subtracting an excess amount δQ of heat supplied from the second heating body 28 to the nip portion from an amount ΔQ required for the first heating body 18 to reach a predetermined target temperature, that is, , Q1 = ΔQ−δQ.

Therefore, in the present embodiment, the control circuit 31 stores the detection signal from the temperature sensor 26 and the memory 3
5 is determined by comparing with a predetermined target temperature of the first heating element 18 recorded in 5, while δQ is determined from a difference between the detected temperature of the temperature sensor 29 and the predetermined target temperature of the pressure roller 23.

The control circuit 31 determines that Q1 = ΔQ−
Trigger pulse corresponding to δQ is applied to first heating element drive circuit 3
By turning ON and OFF to 2, an appropriate amount of heat is supplied from the first heating body 18 and the second heating body 28, and the nip is set to a predetermined temperature.

Further, when the temperature detected by the temperature sensor 29 is lower than the predetermined target temperature of the pressure roller 23, the control circuit 31 determines the temperature detected by the temperature sensor 29 and the target temperature of the pressure roller 23. From the difference from the temperature, the shortage δQ ′ of the heat supplied from the second heating body 28 to the nip is obtained, and Q1 =
By turning ON / OFF the trigger pulse corresponding to ΔQ + δQ ′ to the first heating element drive circuit 32, an appropriate amount of heat is supplied from the first heating element 18 and the second heating element 28, and the nip is heated to a predetermined temperature. Is set to

The control circuit 31 set as described above
Compares the detection signal from the temperature sensor 26 with a predetermined target temperature of the first heating element 18 recorded in the memory 35, and compares the detection signal from the temperature sensor 29 with the memory 3
5 is compared with a predetermined target temperature of the pressure roller 23, and a predetermined motor drive command signal is transmitted.

The first heating element drive circuit 32 provided in the control section 30 drives the first heating element 18 when it receives a heating drive command signal from the control circuit 31.

When a predetermined trigger pulse is turned on by the control circuit 31, the first heating element drive circuit 32 operates such that an alternating current of a predetermined phase is supplied from the AC power supply S1 to the first heating element 18. The phase of the AC power supply S1 is also controlled.

The second heating element drive circuit 33 provided in the control section 30 drives the second heating element 28 when receiving a heating drive command signal from the control circuit 31.

When a predetermined trigger pulse is turned on by the control circuit 31, the second heating element drive circuit 33 supplies an alternating current of a predetermined phase to the second heating element 28 from the AC power source S2. The phase of the AC power supply S2 is also controlled.

Next, the fixing device 13 by the control unit 30
The control procedure such as will be described with reference to FIGS.

FIG. 4 is a flowchart showing the control procedure of the control unit 30.

First, when the image forming apparatus 1 is started up, the control unit 30 is activated to transmit the heating drive command signal to the second heating element drive circuit 33.

The second heating element driving circuit 33 that has received the heating driving command signal from the control circuit 31 drives the second heating element 28 to heat.

On the other hand, the temperature sensor 29 started with the start-up of the image forming apparatus 1 detects the surface temperature of the pressure roller 23 and transmits a detection signal based on the detection to the control circuit 31. (Step 100) The control circuit 3 receiving the detection signal from the temperature sensor 29
1 compares this detection signal with a predetermined target temperature on the surface of the pressure roller 23 recorded in advance in the memory 35, and turns on a predetermined trigger pulse to the second heating element drive circuit 33;
Turn off. (Step 101) Upon receiving the predetermined trigger pulse from the control circuit 31, the second heating element driving circuit 33 causes the AC power supply S2 to supply an AC current of a predetermined phase from the AC power supply S2 to the second heating element 28. Is controlled in phase.

Therefore, the pressure roller 23 is
Heat is supplied by the heating of No. 8 to set a predetermined target temperature.

Next, at the same time as the start of the copying operation in the image forming apparatus 1 or after a predetermined time, the control circuit 31 transmits a motor drive command signal to the motor drive circuit 34.

The motor drive circuit 34 having received the motor drive command signal from the control circuit 31 drives the motor 27 based on the motor drive command signal.

Therefore, the film 22 stretched with a predetermined tension by the motor 27 is moved to the first heating element 18.
Is driven in the direction of the arrow V while sliding on the first surface of.

Next, a predetermined time before the fixing operation of the fixing device 13 is started, the control circuit 31
The above-mentioned heating drive command signal.

The first heating element driving circuit 32 that has received the heating driving command signal from the control circuit 31 drives the first heating element 18 to heat. (Step 102) At the same time, the temperature sensor 26 detects the heating temperature of the first heating element 18 and transmits a detection signal based on this detection to the control circuit 31. (Step 103) On the other hand, the temperature sensor 29 detects the heating temperature of the second heating element 28 and transmits a detection signal based on the detection to the control circuit 31. (Step 104) Accordingly, the control circuit 31 which has received the detection signal from the temperature sensor 26 and the detection signal from the temperature sensor 29 outputs the detection signal from the temperature sensor 26 and the detection signal from the temperature sensor 29. From the predetermined target temperature of the first heating element 18 recorded in the memory 35 and the predetermined target temperature of the pressure roller 23 recorded in the memory 35, The amount of heat Q1 to be supplied to the first heating element drive circuit 32 is turned on and off for the trigger pulse corresponding to Q1.

The control circuit 31 controls the pressure roller 23
Is output to the second heating element drive circuit 33 by a trigger pulse corresponding to maintaining the detection at the temperature detected by the temperature sensor 29.
N, turn OFF.

Therefore, the first heating element driving circuit 32, which has received the predetermined trigger pulse from the control circuit 31, supplies the first heating element 18 with an alternating current of a predetermined phase from the AC power supply S1. The phase of S1 is controlled. (Step 105) On the other hand, the second heating element drive circuit 33 which has received the predetermined trigger pulse from the control circuit 31 causes the AC power source S2 to supply the second heating element 28 with an AC current having a predetermined phase. The phase of the power supply S2 is controlled. (Step 106) Therefore, heat supply from the first heating element 18 to which the alternating current of the predetermined phase is supplied from the AC power supply S1 and the second heating element 28 to which the predetermined phase of the alternating current is supplied from the AC power supply S2. As a result, the first surface of the first heating element 18 and the pressure roller 23
During the fixing operation, the nip portion is set and maintained in a temperature range suitable for fixing the unfixed visible image to the recording paper, thereby forming a high-quality image. be able to.

Then, upon completion of the fixing operation, the control circuit 3
Reference numeral 1 denotes a transmission of a motor drive command signal to the motor drive circuit 34 and a first heating element drive circuit 3 based on the temperature sensor 26.
O of the trigger pulse to the second heating element drive circuit 33
After stopping N and OFF, a control operation before the start of image formation is performed to set the surface temperature of the pressure roller 23 to a target temperature before the copying operation.

[0089]

As described above, according to the first aspect of the present invention, during the fixing process, both the temperatures are maintained so that the nip portion is maintained at the target temperature for the fixing process. Both heating means perform a heating operation in accordance with the detection result of the detection object, and in accordance with the detection result of the second temperature detection object so that the pressurized body is maintained at the target temperature for fixing standby during the fixing standby. Since the second heating means performs the heating operation, the heating of both heating means always raises and maintains the nip portion at the target temperature regardless of the temperature of the atmosphere inside or outside the main body of the fixing device. be able to.

Further, according to the second invention of the present application, a heating resistor is coated on one surface of a thin substrate mainly composed of ceramics, and is in contact with the other surface. Since the transfer material carrying the unfixed image is heated via the fixing member by the ceramic heater in which the first temperature detecting member is disposed in proximity, the temperature of the nip can be quickly raised to the target temperature. it can.

Further, according to the third invention of the present application,
Since the pressurized body is heated by the halogen heater arranged along the axis of the pressurized body in the hollow portion of the pressurized body, it is possible to compensate for the temperature rise of the pressurized body due to the heating of the first heating means. it can.

Further, according to the fourth aspect of the present invention, the control means controls the detection results of the two temperature detectors so that the nip portion is maintained at the target temperature for the fixing process during the fixing process. Control both heating means so that both heating means perform the heating operation in accordance with the second temperature detecting element so that the pressurized body is maintained at the target temperature for fixing standby during fixing standby. Since the second heating drive unit is controlled so that the second heating unit performs the heating operation according to the detection result, the heating of both the heating units enables the second heating unit to perform the heating operation regardless of the temperature of the atmosphere inside or outside the main body of the fixing device. In addition, it is possible to always perform temperature control in which the temperature of the nip is raised and maintained at the target temperature.

Further, according to the fifth invention of the present application,
A fixing element is formed by a ceramic heater in which a heating resistor is coated on one surface of a thin plate made mainly of ceramics and a first temperature detector is arranged in contact with or close to the other surface. The transfer material carrying the unfixed image is heated via the nip, so that the temperature of the nip can be quickly raised to the target temperature.

Further, according to the sixth aspect of the present invention, the pressurizing member is heated by the halogen heater disposed in the hollow portion of the pressurizing member along the axial direction of the pressurizing member. It is possible to supplement the temperature rise of the pressurized body by the heating of the first heating means.

Further, according to the seventh invention of the present application,
During the fixing process, the control unit of the temperature control unit provided in the image forming apparatus controls both the heating units according to the detection results of the two temperature detectors so that the nip portion is maintained at the target temperature for the fixing process. Both heating driving means are controlled so as to perform the heating operation, and during the fixing standby, the second temperature detecting body detects the second temperature according to the detection result of the second temperature detecting body so that the pressure body is maintained at the target temperature for the fixing standby. The second heating driving means is controlled so that the heating means performs the heating operation, so that the heating of both the heating means always causes the nip portion to be irrespective of the temperature of the atmosphere inside or outside the main body of the fixing device. The temperature can be raised to and maintained at the target temperature, thereby providing an image forming apparatus that provides high-quality images with suitable image gloss and image density.

Further, according to the eighth invention of the present application, a heating substrate is coated on one surface of a thin substrate mainly composed of ceramics, and is contacted with or contacted with the other surface. Since the transfer material carrying the unfixed image is heated via the fixing member by the ceramic heater in which the first temperature detecting member is disposed in proximity, the temperature of the nip portion can be quickly raised to the target temperature. An image forming apparatus including a fixing device can be provided.

Further, according to the ninth invention of the present application,
Since the pressurized body is heated by the halogen heater arranged along the axis direction of the pressurized body in the hollow portion of the pressurized body, the temperature rise of the pressurized body by the heating of the first heating means is supplemented. An image forming apparatus having the fixing device provided can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating a schematic configuration of an image forming apparatus according to a first embodiment of the invention.

FIG. 2 is a schematic cross-sectional view illustrating a schematic configuration of a fixing device illustrated in FIG.

FIG. 3 is a block diagram of a temperature control unit that controls the fixing device of FIG. 2;

FIG. 4 is a flowchart showing a control procedure by a control unit shown in FIG. 3;

[Explanation of symbols]

 Reference Signs List 18 first heating element (first heating means) 19 drive roller 22 film (fixing element) 23 pressure roller (pressure element) 26 temperature sensor (first temperature detection element) 28 second heating element (second element) (Heating means) 29 temperature sensor (second temperature detecting body) 30 temperature control means 31 control circuit (control means) 32 first heating body drive circuit (first heating drive means) 33 second heating body drive circuit (second Heating drive means)

Claims (9)

[Claims] A first heating means for heating a sheet-shaped transfer material carrying an unfixed image via an endless belt-shaped fixing member;
A cylindrical or substantially cylindrical or columnar or substantially columnar rotatable pressure member which is pressed against the fixing member via the transfer material, and a first temperature detector which detects the temperature of the first heating means And a second heating means for heating the pressurized body, and a second temperature detector for detecting the temperature of the pressurized body, wherein the second temperature detectors are pressed against each other. It is disposed upstream from the nip formed between the body and the pressure body with respect to the rotation direction of the pressure body, and during the fixing process, the nip is maintained at the target temperature for the fixing process. In accordance with the detection results of the two temperature detectors, both heating means perform a heating operation, and during the fixing standby state, the second temperature detecting body is maintained so that the pressure body is maintained at the target temperature for the fixing standby state. The second heating means is set to perform the heating operation according to the detection result of The fixing device according to claim. 2. The first heating means includes a first substrate having ceramics as a main component, one surface of which is coated with a heating resistor and a first substrate which is in contact with or close to the other surface. The fixing device according to claim 1, wherein the fixing device is a ceramic heater on which a temperature detector is disposed. 3. The fixing device according to claim 1, wherein the second heating unit is a halogen heater disposed in a hollow portion of the pressure member along an axial direction of the pressure member. apparatus. 4. A temperature control means for controlling the temperatures of a fixing member and a pressure member provided in the fixing device according to claim 1.
A first heating drive unit that drives the first heating unit, a second heating drive unit that drives the second heating unit, and a control unit that controls the driving of each heating unit by both the heating drive units. During the fixing process, the control unit controls both the heating units to perform the heating operation in accordance with the detection results of the two temperature detectors so that the nip portion is maintained at the target temperature for the fixing process. The heating drive means is controlled, and during the fixing standby,
The second heating means controls the second heating driving means so that the second heating means performs a heating operation in accordance with the detection result of the second temperature detection body so that the pressure body is maintained at the target temperature for fixing standby. Temperature control means, characterized in that: 5. The first heating means includes a heat-generating resistor coated on one surface of a thin plate mainly composed of ceramics, and abutting or approaching the other surface. The temperature control means according to claim 4, wherein the temperature control means is a ceramic heater on which the temperature detector is disposed. 6. The second heating means, wherein the second heating means comprises:
The temperature control means according to claim 4 or 5, wherein the temperature control means is a halogen heater disposed in a hollow portion of the pressure body along an axial direction of the pressure body. 7. A fixing device according to claim 1, wherein
An image forming apparatus comprising the temperature control unit according to claim 1. 8. The first heating means includes a heat-generating resistor coated on one surface of a thin plate mainly composed of ceramics and abutting or approaching the other surface. The image forming apparatus according to claim 7, wherein the image forming apparatus is a ceramic heater on which a temperature detector is disposed. 9. The image according to claim 7, wherein the second heating means is a halogen heater disposed in the hollow portion of the pressurizing body along the axial direction of the pressurizing body. Forming equipment.