JPH06130856A - Fixing device and image forming apparatus - Google Patents

Abstract

(57) [Summary] [Objective] One of the objects of the present invention is to reduce the warm-up time by using a heat roller having a smaller size and a lower heat capacity than before, and to fix high speed and low power consumption, especially power saving in standby mode. It is to realize the device. [Structure] After the power of the fixing device is turned on, the heater is energized with full power until the temperature of the fixing roller reaches the switching temperature Tp, and thereafter the power is supplied with low power. In addition, the heater is always energized while the transfer material is being passed through the fixing device. Further, the copy enable signal is output when the temperature of the fixing roller reaches the standby temperature Tw.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an electrophotographic copying machine, L
The present invention relates to a thermal fixing device provided with a temperature / power control unit for a BP or the like.

The present invention also relates to a device having a separating claw for separating the transfer paper from the rotating body.

Further, the present invention relates to a fixing device of an electrophotographic image forming apparatus, and more particularly to temperature detection of its heating device.

The present invention also relates to an image forming apparatus having auxiliary fixing means in addition to the main fixing means.

[0005]

2. Description of the Related Art Conventionally, with respect to temperature control of heat roller fixing, it has been basically to always maintain a constant temperature.
This is because the fixing roller has a structure in which a sufficiently large amount of heat is stored so that the roller surface temperature does not drop significantly when a few sheets of paper are passed.

However, in such a system, there are problems that the entire copying apparatus becomes unnecessarily hot, the power consumption becomes large, and the like. Therefore, the temperature at the time of standby is increased by increasing the temperature at the time of copying by further improvement. Something to lower,
A method has been proposed in which the temperature of the heating roller is raised for a while immediately after the cold fixing device is first heated and then the temperature of the heating roller is lowered if the entire fixing device is sufficiently heated.

Next, another conventional example will be described. Conventionally, as a fixing device in an image forming apparatus, a transfer paper is passed between two rollers, and a heater is provided in the roller on the side in contact with the surface of the transfer paper carrying a toner image, and fixing is performed by applying pressure and heat. There is a structure in which some separation claws for separating the transfer paper from the fixing roller are brought into contact with the fixing roller.

Next, another conventional example will be described. Generally, in a fixing device, a separation claw is provided in constant contact with the fixing roller so that the transfer paper does not wind around the fixing roller after fixing, and the transfer paper is separated and discharged by the separation claw. . In this case, the surface of the fixing roller is usually coated with Teflon (registered trademark),
Also, oil is applied to this surface. Therefore, even if the separation claw is in constant contact with such a fixing roller, the coefficient of friction between the fixing roller and the separation claw is small before the transfer paper has passed, so that the tip of the separation claw may not damage the fixing roller. Few.

However, at the time of copying, the oil applied to the surface of the fixing roller is absorbed by the transfer paper and then comes into contact with the separating claw, so that the friction coefficient between the separating claw and the fixing roller becomes large, This fixing claw tip damages the fixing roller. As a result, toner is deposited on the scratched portion of the fixing roller and appears on the copy, which may cause deterioration of image quality.

On the other hand, when the contact pressure of the separation claw on the fixing roller is reduced in order to reduce the friction between the fixing roller and the separation claw, toner is accumulated between the roller and the separation claw to separate the original separation of the claw. Ceases to function. Therefore, as described in Japanese Utility Model Laid-Open No. 55-112259, a device for cleaning the separating claw has been proposed.

Next, another conventional apparatus will be described. As a method of thermally fixing a copy sheet onto which a toner image has been transferred in a copying machine, two thin plate-shaped heating elements having a large surface area are arranged in parallel and electrically heated to pass the copy sheet through this gap. Alternatively, there is a method in which rod-shaped heating elements are arranged in parallel vertically and a copy sheet is passed through this gap.

In the fixing device for carrying out these methods, it is necessary to maintain the temperature inside the fixing device in an optimum state for fixing the toner powder transferred to the copy sheet. For this reason, the temperature inside the fixing device is maintained at an optimum value by a temperature controller in which a temperature detector such as a CA thermocouple is arranged directly on the heating element of the fixing device or in the vicinity of the heating element.

In such a fixing device, when the temperature controller is deteriorated or damaged, or when the temperature detector directly attached to the heating element receives electrical noise from other parts of the copying machine, Alternatively, when part or all of the temperature detecting element directly joined to the heating element is released from the surface of the heating element, the power supplied to the heating element of the fixing device cannot be controlled normally. As a result, excessive power is supplied to the heating element, and when the copy sheet jams in the fixing device in this state, paper burning (blackening or burning of the sheet) may occur.

In order to prevent these, JP-A-52-8
8033, JP-A-52-89331, and JP-A-54-11.
1081, Japanese Patent Laid-Open No. 54-121134, etc., there has been proposed an abnormality detection method by controlling a heating element.

In addition to these, a thermoswitch using a metal bimetal or a thermal fuse is used to directly cut off the power supply. However, these thermal fuses and thermoswitches have poor thermal responsiveness and are not sufficient as methods for preventing overheating, and even if these conventionally used methods are combined, an accident such as smoking may occur. In particular, an accident may occur when a contact failure or disconnection of a thermoswitch or thermocouple used for temperature detection overlaps with a rare usage condition. In order to prevent these problems, it has been proposed to use a plurality of thermistors in JP-A-54-41141 and the like.

Next, another conventional example will be described. A heat roller fixing device is known as one of toner image fixing systems used in electrophotographic copying machines and the like. In this apparatus, if the surface temperature of the heat roller is lower than the appropriate temperature, sufficient fixing is not performed and the toner adheres to the heat roller, causing an offset. Therefore, if the fixing is performed by controlling the surface temperature of the heat roller to be constant, the temperature of the toner to which the heat roller makes contact changes depending on the room temperature, the temperature inside the apparatus, or the like, which is not desirable. Therefore, in order to keep the surface temperature of the heat roller, the toner image temperature, and the in-machine temperature constant, and to always perform stable fixing, a means for keeping the temperature of the sheet on which the toner image is formed in a predetermined temperature range in advance is provided. A temperature control device in a fixing device for performing temperature control so as to maintain a temperature difference between a toner image and a sheet on which a toner image is formed in a preset constant range is proposed in, for example, Japanese Patent Application Laid-Open No. 50-161244. There is.

Next, another conventional example will be described. A heat roller fixing device is known as one of the methods for fixing a toner powder image in a dry electrophotographic apparatus. According to this method, the toner image on the photoconductor is transferred onto the sheet, passes through the transport section, and is fixed by the thermal fixing device.

As an example of such a thermal fixing device, there is one in which a fixing roller having a heater inside and a pressure roller made of an elastic material are heated and nipped and conveyed to perform fixing. According to this, the amount of heat transferred from the roller to the paper is determined by the temperature of the roller, the nip amount by the upper and lower rollers, and the paper passing speed, and thereby the fixing property is determined.

Therefore, in a high-speed copying machine or the like having a high paper passing speed, the roller diameter and the contact thickness of the roller pair are increased to increase the nip amount in order to increase the contact (passing) time of the paper with the rollers. I'm out. In addition, since the amount of heat absorbed by the paper per unit time is large due to the large number of sheets of paper passing, the roller heating heater is increased in electric power to set the roller temperature to a temperature at which the toner powder image can be fixed (about 180 to 200 ° C.). ) Is maintained.

On the other hand, in order to prevent the temperature rise of the sensors arranged around the heat fixing device and to prevent the heat conduction to the optical unit arranged above the heat fixing device, all or the rear part of the heat fixing device. A cooling fan is installed on the machine to discharge heat to the outside of the machine.

[0021]

However, the above-mentioned conventional example has the following problems. First, in the conventional example in which the heating roller may be controlled at a temperature lower than the temperature at the time of copying, fixing unevenness such as over-fixing due to overshoot of temperature control or fixing failure when the heater is turned off occurs in the first few copies. There was a problem that it would occur.

Therefore, there has been proposed a method of reducing the electric power applied to the heating roller when the temperature of the heating roller reaches the set temperature for copying to reduce the temperature ripple (peaks and valleys of temperature) at the time of stabilization. Even if the electric power is suddenly reduced after reaching the set temperature for copying, as described above, due to the thermal inertia that rises from the set temperature for standby to the set temperature for copying, overshoot and subsequent heater O
It was not possible to solve the fixing unevenness in the FF time.

Further, in the above-mentioned conventional example, there is also a problem that the warm-up time from the power-on until the temperature of the heating roller reaches the set temperature at the time of copying becomes long. A method of starting continuous copying at a low temperature was also proposed. However, since the electric power supplied until the temperature reaches the set temperature during copying, overshooting and fixing nonuniformity after the heater is turned off for a long time also occur.

The above problems of the conventional examples are caused by the use of a heating roller having a large thickness and a large diameter and a relatively large heat capacity in order to sufficiently store heat in the heating roller. ing. Therefore, a method of using a heating roller having a low heat capacity has been proposed, but such a roller has a problem that a sensitive and expensive temperature sensor is required in order to cause a rapid temperature change in a short time.

Further, according to the above-mentioned conventional example in which the separating claw is brought into contact with the roller, it is known that a rubber roller having a soft surface is used in the fixing roller of the high speed machine. In this case, the fixing roller is rotated. However, if the separation claw is heated and pressed on the fixing roller for a long time, the tip of the separation claw slightly enters the surface of the fixing roller, and that portion becomes an indentation as shown in FIG. The fulcrum 104 of rotation of the separation claw 103 is generally on the side opposite to the fixing roller 101 with respect to the tangent line passing through the contact points between the fixing roller 101 and the separation claw 103, and when the fixing roller 101 is rotated in that state, To the fixing roller 101
There is a risk that the separation claw 103, which has already entered the surface of the fixing roller 101, may dig into the surface layer of the fixing roller 101 and damage the fixing roller 101 due to the force acting toward the center of the fixing roller 101.

Further, according to the above-mentioned conventional example having the cleaning device for the separation claw, when the tip of the claw is cleaned by the above-mentioned cleaning device, the fluororesin coating layer on the tip of the claw is peeled off or the tip of the claw is damaged. In some cases, the separation claw may have a short life.

Further, according to the conventional example using a plurality of thermistors, a plurality of thermistors may cause an abnormal state or a wire disconnection accident, and the contact method is more likely to cause wire disconnection due to its vibration. Further, mounting a plurality of contact type thermistors increases the problems such as roller scratches. Further, although the non-contact thermistor is strong against disconnection, the reliability of the detected temperature is not so high as that of the contact type.

Further, in the conventional example in which the temperature difference between the heat roller and the paper is kept within a certain range, the preheating means is controlled so that it always operates within a certain temperature range. When the paper is subjected to the fixing action by the main fixing device more than once, the curl becomes large and causes a jam in the image forming device, or the temperature of the paper discharged outside the image forming device is too high, and the user feels uncomfortable. There is a risk that the temperature inside the machine will rise significantly and that extra power will be required.

Further, in the conventional example in which the contact time of the paper with the roller is increased by increasing the nip amount, if the roller diameter is increased in order to increase the nip amount, the space of the apparatus is increased and the cost is increased. On the other hand, when the contact pressure of the roller pair is increased, there is a problem in increase of driving torque and durability of the roller, and there is a limit in increasing the nip amount. Further, when the number of sheets of paper passing per unit time increases and the amount of heat absorbed by the paper per unit time increases, further power consumption is required to maintain the surface temperature of the heat roller at the fixable temperature. However, in the present day when energy saving is called for and how to reduce power consumption has become an issue, increasing power consumption has been an unacceptable problem.

A first object of the present invention is to solve the above-mentioned problems, to avoid over-fixing and under-fixing without using a highly sensitive and expensive temperature sensor, and to shorten the warm-up time and increase the speed. To realize a low power consumption fixing device.

A second object of the present invention is to provide an image forming apparatus which does not damage the rotating body such as the fixing roller by the separating claw.

A third object of the present invention is to provide a fixing device which does not damage the separating claw even when the separating claw cleaning device is provided.

A fourth object of the present invention is to provide a fixing device capable of surely detecting an abnormality of the temperature detector.

A fifth object of the present invention is to fix the paper without curling the paper and consuming no extra power even when the temperature difference between the heat roller and the paper is kept within a certain range. To provide a device.

A sixth object of the present invention is to provide a fixing device capable of obtaining a good fixing property with a limited nip amount and a limited power consumption.

[0036]

According to the first invention of the present application,
The first purpose is to fix the transfer material by sandwiching it, to convey the transfer material through the fixing means, to heat the transfer material through the fixing means, to detect the temperature of the fixing means, and to detect the temperature. In a fixing device provided with a temperature / power control unit for supplying a predetermined power to the heating unit based on the temperature detected by the detection unit and maintaining the heating unit at a predetermined temperature, the temperature / power control unit is: When the transfer material is nipped by the fixing means, the heating means is always energized, and after the power of the fixing device is turned on, the temperature of the fixing means reaches a predetermined standby temperature lower than the fixing temperature at the time of fixing. When a signal indicating that the fixing operation is possible is output to the external image forming means side, and the temperature of the fixing means reaches a predetermined switching temperature set between the fixing temperature and the standby temperature. Is achieved by being set to a lower power than the power supplied to the electric power supplied to the fixing unit after the power is turned on until the standby temperature reached.

Further, according to the second invention of the present application, the second object is to provide a rotating body for sandwiching and transporting the transfer material, and a separating claw arranged to abut the rotating body and for separating the transfer material. The image forming apparatus includes a moving means for reciprocally moving the separating claw in the axial direction of the rotating body, and the moving amount of the separating claw by the moving means corresponds to the contact of the separating claw before the rotation of the rotating body. This is achieved by setting the width to be larger than the width of the contact portion.

Further, according to the third invention of the present application, the third object is to provide a pair of fixing rollers for nipping and conveying the transfer material, and to arrange so as to contact the surface of at least one of the pair of fixing rollers. In a fixing device having a separated separation claw and a cleaning device that is disposed so as to come into contact with the tip of the separation claw and that cleans the tip, a portion of the tip of the cleaning device that contacts the separation claw is provided. This is achieved by providing a means for holding or supplying the release agent.

According to the fourth invention of the present application, the fourth object is to provide a heating member arranged so as to come into contact with the unfixed developer image on the transfer material, and a heating member disposed inside the heating member. In a fixing device having an electric heating element provided and a temperature-sensitive element for detecting the temperature of the heating member, at least two temperature-sensitive elements are arranged in the vicinity of the heating member, and at least two of them are provided. One is not in contact with the heating member, and the energization of the electric heating element is set to stop when the signal of the temperature-sensitive element arranged in the non-contact exceeds a certain value. Achieved by

Further, according to the fifth invention of the present application, the fifth object is to provide an image forming portion for forming an unfixed developer on a transfer material, a main fixing means for heating or pressurizing the transfer material, In an image forming apparatus provided with an auxiliary fixing unit that holds the temperature of the transfer material in a predetermined temperature range before the transfer member is conveyed to the main fixing unit, the auxiliary fixing unit once sets the main fixing unit. This is achieved by setting the transfer material so that it will not operate when the transfer material is fed again to the image forming section for double-sided image formation or multiplex image formation after the fixing operation is performed.

According to the sixth aspect of the present invention, the sixth object is to provide an image forming means for forming an unfixed developer image on a transfer material, and an unfixed developer by heating and pressurizing the transfer material. In an image forming apparatus comprising a fixing device for fixing an image and a transfer material conveying means for guiding the transfer material from the image forming means to the fixing device, a suction fan arranged below the fixing device, This is achieved by providing a duct that communicates with the suction fan and extends from below the fixing device to below the transfer material conveying unit.

[0042]

According to the first aspect of the present invention, when the power of the fixing device is turned on, the temperature / power control means starts energizing the heating means, and the temperature of the fixing means detected by the temperature detecting means is the same as that at the time of fixing. When a predetermined standby temperature lower than the fixing temperature is reached, a signal indicating that the fixing operation is possible is output to the external image forming unit side. Therefore, it is considered that the transfer material carrying the unfixed developer image is conveyed to the fixing device when the temperature of the fixing means does not reach the fixing temperature, but the transfer material is sandwiched by the fixing means. While the fixing unit is being energized, a predetermined amount of electricity is always supplied to the fixing unit, so that excellent fixing is performed. On the other hand, when the temperature of the fixing means reaches a predetermined switching temperature set between the fixing temperature and the standby temperature, the power supplied to the heating means is more than the power supplied until the standby temperature is reached. Is also low power, and the energization for the transition is performed with low power. As a result, the overshoot after the temperature of the fixing unit reaches the fixing temperature is suppressed low, and the temperature ripple is reduced during the fixing operation. However, while the transfer material is being fed to the fixing means, the heating means is always energized by a predetermined amount, so that good fixing is performed.

According to the second invention of the present application, the separating claw arranged so as to contact the rotating body is moved in the axial direction of the rotating body by the moving means before the rotating body is rotated. The amount of movement is set to be larger than the width of the contact portion of the separation claw before the rotation of the rotating body. Therefore, even if the contact portion of the separating claw is an indentation on the surface of the rotating body, since the contact portion moves before the rotation of the rotating body, even if the rotating body rotates, Does not damage the surface.

Further, according to the third invention of the present application, the transfer material sandwiched and conveyed by the fixing roller pair is separated by the separating claw arranged so as to come into contact with at least one of the fixing roller pair. Although the paper is peeled off from the roller surface and discharged, the paper dust and the developer adhering to the roller surface may be accumulated on the tip of the separation claw. However, the cleaning device arranged so as to come into contact with the tip portion of the separation claw cleans the tip portion by coming into contact with the tip portion to remove the adhering matter. The tip of the cleaning device is provided with a means for holding or supplying a release agent, which reduces the friction coefficient at the time of contact with the separating claw and prevents the separating claw from being damaged.

Further, according to the fourth invention of the present application, the temperature of the heating member is detected by the temperature sensitive element arranged so as to be in contact with the heating member, and the predetermined temperature is maintained based on the signal thereof. Therefore, highly accurate temperature control based on the highly reliable detection signal is performed. Therefore, when a failure such as a wire breakage occurs in the temperature-sensitive element arranged so as to come into contact with it, appropriate temperature control cannot be performed, and the temperature of the heating member rises abnormally. However, at least one of the two or more temperature-sensitive elements is disposed in the above-mentioned heating member in a non-contact manner and is a type in which an accident such as disconnection does not easily occur. When the temperature sensing element detects an abnormal temperature rise in the heating member, the power supply to the heating device is immediately stopped. As a result, it is possible to prevent a smoking accident or the like from occurring due to a failure of the contact type temperature sensing element.

Further, according to the fifth aspect of the present invention, the transfer material on which the unfixed developer image is formed in the image forming section is heated to a predetermined temperature range by the auxiliary fixing means before being conveyed to the main fixing means. After that, it is conveyed to the main fixing unit. Therefore, the temperature of the unfixed developer image on the transfer material, the temperature inside the apparatus, and the temperature of the main fixing unit are maintained at a predetermined temperature, and stable fixing is always performed. Moreover, when the transfer material is conveyed again to the image forming section for double-sided image formation or multiple image formation, the auxiliary fixing unit does not operate, so that the transfer material is not heated more than necessary, and the curl does not occur. It does not cause paper jams or paper jams, and saves extra power consumption.

According to the sixth aspect of the invention, the transfer material on which the unfixed developer image is formed in the image forming section is guided and conveyed to the fixing device by the transfer material conveying means. The heat of the fixing device is transferred to the transfer material conveying device by a duct connecting the fixing device and the transfer material conveying device and a suction fan provided below the fixing device. Therefore, the transfer material passing on the transfer material conveying means is appropriately heated and becomes higher in temperature than ever before, the amount of heat taken from the fixing device for fixing is smaller than before, and the power consumption of the fixing device is also reduced. To be

[0048]

Embodiments 1 to 16 of the present invention will be described with reference to the drawings.

<Embodiment 1> First, Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a schematic configuration of a small fixing device having a low heat capacity, which is used in this embodiment and in comparing the temperature and the fixing property with this embodiment. FIG. 2 is a block diagram showing the temperature / power control means of the fixing device of the present invention. FIG. 3 shows the evaluation of the fixing roller temperature and the fixing property for each copy when the paper is continuously fed by the fixing device using the temperature / power control method of the present invention. FIG. 4 is a block diagram showing the temperature / power control means in the experimental example of the present embodiment. FIG. 5 shows the temperature control and power control states during warm-up and copying in the experimental example. FIG. 6 is a diagram showing the evaluation of the fixing roller temperature and the fixability during continuous sheet feeding when the conventional power / temperature control method is used.

The fixing roller 2 in the fixing device shown in FIG.
Is an aluminum cored bar having an outer diameter of 18 mm and a wall thickness of 0.5 mm, which is coated with ethylene tetrafluoride on the surface thereof.
A warm-up time of about 10 seconds or more can be realized at 0 W. As the pressure roller 8, a roller having an outer diameter of 15 mm having a silicone rubber surface layer on a silicone sponge was used. This fixing device has a process speed of 100m
It was rotated at m / sec, and 15 sheets of A4 continuous copy speed were passed per minute for fixing.

First, a conventional temperature control system to be compared with the present invention will be described. In this method, in the warm-up state after the power is first turned on in the morning, the temperature is increased with the target temperature Tw which is lower than the set temperature Tc at the time of copying, and in the copy state the heater is set to maintain the set temperature Tc. Is turned on and off. In addition, this system controls ON / OFF of the total power in both warm-up and copy states. The set temperature Tc during copying at this time is
It is set to 190 ° C. from the lower limit of fixing or the upper limit of heat resistant temperature of the fixing device configuration. In addition, the standby temperature T
w is 160 as the lower limit temperature at which one copy can be fixed.
℃ was made.

FIG. 6 shows the results of the surface temperature of the fixing roller and the fixability of each paper when 9 sheets are continuously copied by such a conventional method.

As can be seen from FIG. 6, the set temperature Tw = 160 ° C. is set as the target temperature in the warm-up state after the power is first turned on in the morning when the entire apparatus is completely cold, and the set temperature Tc = when copying. The temperature is controlled so as to maintain 190 ° C. Further, in FIG. 6, the number of copies 1 to 9
The sections indicated by the numbers 1 to 9 are the section P in which the first to ninth sheets of paper pass through the fixing roller, and the section in which no sheet of paper passes through the fixing roller between these sheets. Both states with N are represented. The evaluation of fixability is ◎, ○, △, × from the order of good fixability.

As can be seen from the results of FIG. 6, there is a difference in the fixability for each copy even though the temperature is controlled at the same temperature during copying. In the conventional example of FIG. Is bad. Therefore, in such a conventional example, it was found that a fixing device having a small heat capacity such as a small-diameter thin roller has a problem of fixing failure. Further analysis of the results in FIG. 6 revealed the following. (1) The fixing property of the paper passed through when the heater is energized is good. (2) The fixability is good for the first copy that has moved from the warm-up state to the copy state. (3) The fixing property is deteriorated when the paper is passed after a long time has passed since the heater was turned off (valley). (4) Even if the heater is turned off, the fixing is good after the sixth to seventh sheets.

In the above system, since the fixing roller having a small heat capacity is controlled by the heater having a large electric power, the temperature difference between ON and OFF due to the temperature ripple is large, and the ON state is large.
The time is short and the OFF time is long. Therefore, heater ON
When the heater is off, there is no heat flow from the heater through the thin roller, and when the heater is off, there is no heat flow from the heater through the thin roller. The temperature drop on the surface of the roller in contact is large. Further, it is considered that the reason why the fixability after the sixth to seventh sheets is improved is that the temperature of the entire fixing device such as the pressure roller is increased.

Therefore, the present invention performs the following temperature / electric power control to eliminate the problem of using the above-mentioned low heat capacity / thin wall fixing roller without using a highly sensitive and expensive temperature sensor. Solved. (1) When paper is passed through the fixing device, the heater is always energized by a predetermined amount, and the power supplied at this time is set to be lower than the maximum power or for a short time. As a result, it is possible to suppress the occurrence of insufficient fixing, reduce the temperature ripple, and further reduce the power consumption. (2) Especially in the first few sheets of copying, if the heater is always turned on, fixing can be performed at a temperature Tw or higher even if the temperature is lower than the set temperature Tc at the time of copying. To do. As a result, the warm-up time can be shortened. (3) From the warm-up state to the temperature Tw, all electric power is applied so as to rapidly raise the temperature of the fixing roller, and after a predetermined temperature exceeding the temperature Tw, the electric power is relatively slowly raised with a low electric power. As a result, overfixing due to overshoot can be resolved.

In the present embodiment, the temperature / power control as described above is performed by the control means shown in FIG. 2, and the results of the temperature control and the fixing property are shown in FIG. As shown in FIG. 3, it can be seen that the fixing property is improved as compared with the conventional one, and the fixing unevenness for each copy is improved. It was also confirmed that the temperature control results showed little initial overshoot and temperature ripple during the subsequent stabilization.

Next, an experimental example in this embodiment will be described in detail. FIG. 4 is a block diagram showing a schematic configuration of the power / temperature control means in the experimental example, and FIG. 5 is a diagram showing the results of the temperature control and fixing property.

In the control means shown in FIG. 4, when the power switch is first turned on, the fixing heater 3 is energized and the temperature on the surface of the fixing roller 2 rises. Then, this temperature is measured by the temperature detector 7. At this time, the power according to the roller surface temperature is selected according to the power switching temperature TP. That is, as shown in FIG. 5, the roller surface temperature is TP
When the temperature exceeds (= 170 ° C.), the power is switched to a predetermined amount, and overshoot (indicated by TMAX in FIG. 6) when the set temperature becomes high during copying immediately after warm-up and ripple when stable ( (Indicated by TR in FIG. 6) is suppressed small.

In the control means shown in FIG. 4, the switching temperature is 180.
400 ° C above 170 ° C and below 170 ° C
An example has been shown in which the power is switched between W, 600W, and 800W.

Further, in the embodiment shown in FIG. 3, it was switched to 450 W at 170 ° C. or higher and 900 W at less than 165 ° C.
The switching between 900 W and 450 W was performed by half-wave rectification.

Next, preferable selection of the switching temperature and the input power will be described below. For example, it has been found that, even if the total heater power of 900 W is reduced to 400 W at the switching temperature of 165 ° C., when the continuous copying is performed, the first and second sheets of the initial sheet cause fixing failure.

However, when the input power at the switching temperature of 160 ° C. is increased from 400 W to 500 W or 600 W, the initial fixing failure is improved, but when the total power is close to 900 W, overshoot and ripple are generated as in the conventional example of FIG. It becomes undesirably large.

Therefore, when the switching temperature of 165 ° C. is lowered to 400 W and defective fixing occurs, raising the switching temperature to 170 ° C. or 180 ° C. improves the initial defective fixing. However, also in this case, if the switching temperature is raised to a temperature close to the preset temperature during copying, overshoot will occur in the initial stage, which is not preferable.

As described above, the selection of the switching temperature and the input power differs depending on the configuration of the fixing device, the process speed, the copy speed, etc., but if the fixing of several sheets at the initial stage is better than the subsequent fixing, Lower the switching temperature, and raise the temperature if it is bad. In addition, if the fixing is good on the whole both in the initial stage and thereafter, the input power is decreased, and if it is bad, the input power is increased.
Below is also considered.

Regarding the above power control, an example in which half of all waveforms of the AC power supply is given to the heater has been described. In addition to this, as an example of setting the power input to the heater to be short in time, a certain cycle of all waveforms is given. It is sufficient to control the number of the waves to control the number of waves to be given to the heater and to relatively change the electric power. Of course, methods such as phase control can also fully utilize the effects of the present invention.

Regarding the switching temperature, one has been described as shown in FIG. 3 or two as shown in FIG. 4, and the effect of the present invention can be sufficiently obtained at this level. can get.

As described above, according to the temperature / power control system of the present invention, in a heat roller fixing device having a low heat capacity, a small size, and a quick start, the temperature of the fixing device can be controlled without ripples without overshooting, and at the same time, copying can be performed. The start can be started from a lower temperature and the set temperature can be lowered as much as there is less ripple. Therefore, the warm-up time can be shortened easily and the cost can be controlled.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. 7 to 11
7 shows an embodiment of the present invention in the case where a drive system for reciprocating movement (hereinafter referred to as a reciprocating) is taken from the paper discharge roller shaft, and FIG.
Is a structure around the fixing roller, FIG. 8 is a reciprocating mechanism, and FIG.
Indicates the arrangement of drive systems.

The structure of this embodiment will be described. The separation claw 103 is a holder 10 fixed to the mounting plate 106.
5, which is rotatable about the rotary shaft 104,
The tension spring 120 urges the fixing roller 101 against the fixing roller 101 with a predetermined pressure in the direction A of FIG. Mounting plate 10
Reference numeral 6 is rotatable about a rotation shaft 108, and a tension spring 109 applies a biasing force in the direction B of FIG. The fixing roller 101 abuts on a stopper (not shown) and is positioned at a predetermined position of the fixing roller 101.
The position in the reciprocating direction is given a biasing force in the C direction in FIG. 8 by the tension spring 110, and the reciprocating shaft 111 fixed to the mounting plate 106 abuts against the reciprocating cam gear 113 and is fixed. Also, reciprocating gear 1
Reciprocating table 115 to which the motor 13 and the motor 13 are fixed
The reciprocating shaft 116 fixed to the reciprocating cam gear 11
It is positioned by hitting 7. The shapes of the reciprocating gears 113 and 117 are both obtained by cutting a cylinder obliquely and are shown in FIG.

Next, the operation will be described. First, FIG.
In (A), the motor 114 rotates very little by little with the rotation of the fixing roller to rotate the reciprocating cam gear 113. Then, the reciprocating shaft 111 moves on the inclined surface of the cam portion to reciprocate the mounting plate 106 in the axial direction of the fixing roller 101. FIG. 9 (A) shows that when the reciprocating shaft 116 abuts on the apex of the cam portion of the reciprocating cam gear 117,
That is, this is when the mounting plate 106 is located at the deepest side.

When the fixing roller 101 is stopped, an indentation is formed in the contact area between the roller and the separation claw, so that when the copying switch of the copying machine is turned on, after the main switch is turned on, or after the paper is turned on. When the fixing roller 101 starts to rotate from a stopped state as in the pre-rotation after the clogging process, the separation claw 103 may bite into the fixing roller 101. Therefore, in this embodiment, before rotating the fixing roller 101, the motor 118 is driven to move the reciprocating cam gear 117 by 180 ° so that the reciprocating shaft 116 abuts on the most valley portion of the reciprocating cam gear 117 as shown in FIG. 9B. Rotate. In the present invention, since the cam height difference of the reciprocating cam gear 117 and the movement amount y by the separation claw 103 are set to be larger than the claw width x of the separation claw 103, the impression by the separation claw 103 is set. And the separation claw 103 are separated from each other, and then the fixing roller 101
The separation claw 3 will not bite into the fixing roller even if the is rotated. Further, even when the fixing roller 101 is once stopped and then rotated again, the fixing roller 101 is moved from the state of FIG. 9B to the state of FIG. 9A and then rotated as in the above-described operation. , There is no bite into the fixing roller. Even after that, the transition between the state of FIG. 9A and the state of FIG. 9B is repeated after stopping the rotation of the fixing roller 101 and before rotating it again, so that the fixing roller 101 is prevented from biting into the fixing roller. To prevent.

In this embodiment, the rotation of the motor 118 is used to drive the reciprocating cam base 11 via the reciprocating cam gear.
Although 5 is moved, other mechanical such as solenoid,
It may be moved by a physical or electrical mechanism.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 11 shows a sectional view of the fixing device of the present invention. In the figure, 201 is a heat fixing roller having a heat source H such as a halogen heater therein, and 2.
Reference numeral 02 denotes a pressure roller that is brought into pressure contact with the heat fixing roller. The fixing roller 201 is covered with a non-adhesive resin or rubber on a core metal such as aluminum, and is rotated in the direction indicated by the arrow.

The pressure roller 202 has a coating of a relatively thick layer of an elastic material such as silicone rubber on the surface, is pressed against the fixing roller 201, and nips and conveys the toner image support P having the toner powder image T. . The toner powder image T on the support P is heated and fixed on the support P by the fixing roller 201.
A temperature sensitive element 203 such as a thermistor is disposed in contact with the outer peripheral surface of the fixing roller 201, and a detection signal of the temperature sensitive element 203 is sent to a known temperature control means (not shown) so that the temperature of the outer peripheral surface of the heating roller 201 is melted by the toner. Hold at temperature. Reference numeral 204 denotes a separation claw that separates the toner image support P, which is attached to the surface of the fixing roller 201 and is about to be wrapped around the fixing roller, from the fixing roller.

Further, in order to remove the offset toner on the surface of the fixing roller 201, the web cleaning device 20
5 is arranged around the fixing roller 201. In this web cleaning device, a cleaning web 206 that moves while being pressed against the surface of the fixing roller 201, a supply roller 207 that supplies the web, a winding roller 208 that winds the web, and a cleaning roller 206 that fixes the cleaning web 206 to the fixing roller 201. And a pressing roller 209 that presses against the surface of the. Further, 210 is a separation claw that is in contact with the pressure roller 202.

In the present invention, the upper separating claw 204 is made of polyimide or polybenzimidazole coated with a fluororesin such as PFA. By using such a resin having excellent heat resistance and abrasion resistance as the base material of the separating claw, the baking of the fluororesin to be coated can be more complete, and the adhesion of the fluororesin to the base material can be improved. It has been improved and abrasion resistance has been improved. Further, since the lower separation claw 210 comes into contact with the pressure roller 202 having a temperature lower than that of the fixing roller 201, a low cost PPS or polyamide resin having a slightly low heat resistance is used.

Reference numeral 211 is a cleaning tool for cleaning the separation claw 204. FIG. 12 is a perspective view showing the cleaning tool 211 attached to the roller. The cleaning tool 211 is rotatably supported by the cored bar portions at both ends of the fixing roller 201, and is made of heat-resistant resin or metal, and is in contact with the fixing roller cored bar by bearings or bearings. In addition, the cleaning tool 21
1, the rotation and the angle can be set by driving the motor M and the gears 212 and 213. The gear 213 is made integrally with the cleaning tool 211.

A blade 214 is attached to the cleaning tool 211. The blade is formed by integrally molding a fluororubber 215 and a spring member 216, and this is attached to the cleaning tool 211 with a screw 217. This blade is attached to all the portions with the separating claws 204, and if there are four separating claws, they are attached at four positions.

Reference numeral 270 in FIG. 11 denotes a felt roller, which is a roller in which a silicone rubber sponge around the core metal 271 and the element is covered with Nomex felt, and the core metal 271 is supported by a bearing (not shown) and is rotatable. Is. The felt roller is impregnated with silicone oil, contacts the blade 215 of the cleaning tool 211 to clean the tip of the blade 215, and supplies the silicone oil. The blade 215 drives the motor M and the gear 21.
2, 213 rotate along the fixing roller 201, come into contact with the felt roller 270 and pass through it, reach the separation claw 204, and clean the tip of the separation claw 204. This operation is performed, for example, every time 2000 transfer sheets pass through the fixing device. The motor M repeats forward / reverse rotation to perform this operation, and stands by at the position shown in FIG. 11 during the normal fixing operation.

As described above, according to the present invention, the blade provided with the fluororubber is attached to the portion of the cleaning tool that comes into contact with the separation claw, and the silicone oil is supplied to the blade. The coefficient of friction with the tool decreases,
Does not damage the separating claw.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIG. In the above examples, the blade and the felt roller were used, but instead of the blade, a felt in which the blade portion is impregnated with silicone oil is used, or the periphery of the felt is covered with a porous fluororesin film (POREFLON). May be. Alternatively, the web pressing roller 209 may be separated from the fixing roller 201 so that the web 206 supplies oil to the blade of the claw cleaning tool 211. FIG. 13 shows this example. The web unit 205 has a winding shaft 208.
Can be rotated about, and the web unit is turned on and off by this rotation. That is, the ON state indicated by 205 '(indicated by the dotted line) is OFF when indicated by 205
This is the state (indicated by the solid line). The separation claw cleaning tool operates when the web unit is OFF. Then, when the claw cleaning is completed, the claw cleaning tool returns to the illustrated position in the vicinity of the thermistor 203, and then the web unit is turned on by the driving means (not shown). In this way, since the claw cleaning tool is located on the downstream side of the web unit, the jammed paper does not get caught on the claw cleaning tool when a jam occurs due to the separation failure in the fixing device. The tip of the blade is lightly contacted with the web 206 to be cleaned and oil is supplied.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described with reference to FIG. Although the cleaning tool that rotates around the rotation center of the fixing roller position is used in the above embodiment, the cleaning tool may be attached to the separation claw unit side. Figure 1
4 shows this example. 241 is a polyimide film 2
42 is a felt adhered to a polyimide film and is impregnated with silicone oil. Reference numeral 243 denotes a rotating shaft around which the polyimide film 241 is wound, and the rotation of this shaft guides the polyimide film 241 so that the polyimide film 241 can be sent out along the separating claw by the guide 245. 243 is connected to a driving means (not shown), for example, a motor, etc., and normal rotation and reverse rotation are repeated, and the felt 242 slides on the separation claw to clean the separation claw. Note that the film 241 may be a film having heat resistance and appropriate elasticity, and a fluororesin film or the like may be used. Further, porous fluororesin or rubber may be used instead of felt.

<Sixth Embodiment> Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 15 is a sectional view of the fixing device of the present invention. The fixing roller 301 has a heater 303 for heating such as a halogen heater therein, and receives a driving force from a driving motor (not shown) to rotate in the arrow direction. In this fixing roller 301, a heat resistant elastic body 312 such as silicone rubber, fluororubber, or fluorosilicone rubber is provided on the outer peripheral surface of a metal hollow roller core 311 such as aluminum or stainless steel, for example, about 0.5 mm to 0.1 mm. A heat-resistant resin layer 313 such as PTFE or PFA as a release layer
Is provided in a thickness of 10 to 50 μm. Pressure roller 3
02 is rotatably supported by a bearing (not shown).
This roller 302 is brought into pressure contact with the fixing roller 301 at least during fixing by a well-known pressing means, and the metal roller core 3
An elastic layer 315 made of silicone rubber, fluororubber, fluorosilicone rubber or the like is provided on the outer peripheral surface of 14 relatively thickly (for example, about 5 mm to 10 mm). This configuration has one purpose to secure a pressure contact area with the fixing roller.

A temperature sensitive element 304 such as a thermistor thermocouple is provided on the outer peripheral surface of the fixing roller 301, and a detection signal from the temperature sensitive element 304 is introduced to the control means to keep the temperature of the outer peripheral surface of the fixing roller 301 at the toner image melting temperature. ing. Reference numeral 305 denotes a cleaning unit for removing foreign matter such as offset toner and paper dust adhered to the surface of the fixing roller from the roller surface, which is made of heat-resistant non-woven cloth such as Nomex (registered trademark) or Himeron (registered trademark), and is made of dimethyl silicone. A cleaning web 351 impregnated with a release agent such as rubber oil is used. The cleaning web 351 does not necessarily need to be impregnated with a release agent. The cleaning web 351 is in contact with the fixing roller by a pressing roller 352 having elasticity such as silicone rubber, fluororubber, and sponge. Further, the web 351 is moved by the take-up roller 353 which is driven so as to slightly change its contact position from the supply roller 354, and the new surface of the cleaning web 351 always contacts the fixing roller. The guide plate 306 is inclined upward so as to guide the recording material P carrying the unfixed toner image T between the rollers 301 and 302. The guide plate 307 is inclined upward so as to guide the recording material P passing between the rollers 301 and 302 to a conveyance path (not shown). The wrap prevention piece 308 prevents the recording material P from wrapping around the fixing roller 301, and is urged by an urging member (not shown) so that the tip portion 381 is in contact.

Next, the temperature-sensitive element 304 will be described in more detail. A thermistor 341 is a sintered body of a transition metal oxide. 342 is a silicone rubber sponge having a rubber hardness of about 10 ° (Asker-C) so that the thermistor 341 is brought into soft contact with the fixing roller 301. Further, by using a sponge, the heat of the fixing roller 301 is prevented from escaping as a heat insulating material. 343 is a polyimide film (10
0 μm) element 341 and silicone rubber sponge 34
2 is covered to protect the element 341 from oil and toner. 344 is a mounting case. P. S. Made of heat resistant resin such as. 345 is a non-contact temperature detecting element,
It has a gap of about 0.5 mm from the fixing roller.

Next, FIG. 16 shows a schematic structure of the non-contact temperature detecting element used here. Air convection holes 322 are provided on both sides of the thin film thermistor 321. Further, a lead wire 324 made of a metal thin film is provided on the polyimide film 323, and is connected to a lead wire terminal 325. Reference numeral 326 is a hole for positioning the board, and the frame 327 is bonded to the mounting case 344. Further, in FIG. 15, the temperature detecting element 304 is a shaft 34.
6 is rotatable about 6 and is fixed by the spring 347 to the fixing roller 1.
It is pressed against. Reference numeral 309 is a metal support for the temperature detecting element 304.

FIG. 17 shows a contact type thermistor 341.
And the output of the non-contact type thermistor 321 are shown in terms of temperature. The solid line A indicates the contact type output, and the broken line B indicates the non-contact type output. Since the non-contact type shown by the broken line has a slower thermal response, the temperature is slightly lower, but the output is not so large. Further, FIG. 18 shows the relationship when the gap is swung to examine the temperature difference. From this, it can be seen that even if the gap is deviated by about ± 0.1 mm, the difference is not so large. On the other hand, what is indicated by C in FIG. 17 is the temperature of the bimetal inside the thermoswitch, which has been often used for preventing excessive temperature rise from the past. Although not shown in FIG. 15, this thermoswitch is used in contact with the center of the roller. When the temperature inside the thermoswitch is compared with that of the thermistor, it can be seen that the thermal response is extremely poor. This is because the non-contact type thermistor has a smaller heat capacity and better thermal responsiveness, and an abnormal temperature can be detected immediately.

Further, the contact type thermistor and the non-contact type thermistor use different circuits in order to avoid circuit failure and runaway. Further, the non-contact type thermistor has a simple structure because it is used only for detecting an abnormality.

FIG. 19 shows a simple example. First, A is an outlet of a power source, B is a relay, C is a place for converting AC to DC power, D is a DC controller of an image forming apparatus, and TH1 is a contact type thermistor used for temperature control of a fixing device. When TH2 is a non-contact thermistor and the resistance of TH2 becomes smaller than a certain value, the signal from the E comparator cuts off the relay B and the power is not supplied to the main body. As a result, when the fixing device becomes abnormally hot, the power supply is stopped immediately.

<Seventh Embodiment> Next, a seventh embodiment of the present invention will be described with reference to FIG. The same parts as those of the sixth embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the sixth embodiment, the non-contact type thermistor is attached near the contact type thermistor to detect the abnormal temperature rise of the roller, but it is not only used as a safety device but also an auxiliary signal for the roller temperature control. It is also possible to use the signal of the non-contact thermistor as.

FIG. 20 shows an example in which the contact type thermistor is attached to the front side of the fixing roller and the non-contact thermistor is attached to the back side. First, the fixing roller 391 and the pressure roller 39
By passing the paper between the two, the toner is fixed on the paper. A heating unit (not shown) is provided inside the fixing roller 391.
Is provided. Reference numeral 393 is a contact type thermistor for detecting the surface temperature of the fixing roller. Reference numeral 394 denotes a non-contact thermistor, which detects the abnormality of the roller temperature and stops the power supply to the main body as shown in the above embodiment. Further, the non-contact type thermistor 394 can be used not only for detecting an abnormality but also for preventing non-sheet-passage temperature rise, which is a problem when continuously passing small-sized sheets. That is, the abnormality detection is operated at about 300 ° C., and when the temperature of the non-sheet passing portion is raised, control is performed so that the roller temperature does not rise above about 240 ° C. to 250 ° C. Figure 21 shows small size paper (B
5R) is a graph showing the relationship between the temperature detected by the thermistor 393 and the thermistor 394 and the number of passed sheets. In this way, when the normal small-size continuous sheet passing is performed, the temperature of the non-sheet passing portion becomes extremely high, and the fixing roller and its abutting object are damaged. Therefore, when the temperature of the non-contact thermistor is detected to be 240 ° C., for example, control is performed to lower the temperature control temperature of the roller. This is shown in FIG. In this case, when the non-contact thermistor 394 detects 240 ° C., it is controlled so as to lower the temperature controlled temperature of 5 ° C. to 10 ° C. As a result, the temperature of the non-sheet passing portion does not always rise above 240 ° C. Further, when the temperature of the thermistor 393 falls below a certain temperature, the copy speed is lowered or copying is stopped. As a result, it is possible to prevent the formation of a defective image due to the controlled temperature being lowered too much.

In addition, when the non-contact thermistor detects a temperature of 240 ° C. or higher, it is possible to perform control such that one heater is turned off regardless of the contact type thermistor 393.
By doing so, the temperature detected by the contact type thermistor 394 gradually decreases.

<Embodiment 8> Next, an embodiment 8 of the invention will be described with reference to FIG. In this embodiment, it is also possible to use a non-contact thermistor 394 to control the switching of the heater type as a countermeasure against the temperature rise in the non-sheet passing portion by providing a large number of heaters. FIG. 23 shows a fixing roller 391 having two heaters H1 and H2. The heater H1 has a higher light distribution on the front side F, and the heater H2 has a higher light distribution on the back side R. When copying a wide range of papers, both the heaters H1 and H2 are normally turned on. On the other hand, when a narrow paper is copied, the temperature of the non-sheet passing portion rises. Therefore, when the non-contact thermistor 394 detects 240 ° C., the heater of the heater H2 is controlled to be turned off. The roller temperature control is performed by the thermistor 393.

Only when the non-contact thermistor detects 240 ° C. or higher, only the heater H1 is turned on. As a result, it is possible to obtain an apparatus in which the temperature rise of the non-sheet passing portion is prevented without further lowering the productivity of the image forming apparatus.

<Ninth Embodiment> Next, a ninth embodiment of the present invention will be described with reference to FIG. FIG. 24 shows a thermistor 395 that can be turned on and off and a non-contact thermistor 396. This allows the thermistor 395 to be used to correct the non-contact thermistor 396. For example, FIG. 25 shows how the temperature detected by the non-contact thermistor 396 changes with the temperature detected by the thermistor 395 as a reference temperature. FIG. 25C shows detected temperatures of the contact and non-contact thermistors, and FIG. 25A shows the temperature difference. And, the temperature gradient is shown in (B). As shown in this figure, the temperature difference between the non-contact thermistor and the contact thermistor differs depending on the usage conditions.
Since the temperature to be corrected varies depending on the arrangement of the non-contact thermistor and the element variation, accurate control cannot be performed by simply adding or multiplying a constant value. Therefore, first, information indicating which state is in warm-up, standby, or copying is taken in together with the temperature data.

Then, in a constant mode, for example, warm up from 20 ° C. and stand by for 5 minutes, and then copy 999.
Monitor the contact and non-contact temperature during the sheet and standby modes. For example, if the temperature difference changes as shown in FIG. 25A, this actually becomes a digital data string sampled at a fixed time. This data string

[0099]

[Outer 1] I will write. Then, in order to estimate the contact thermistor output temperature from the non-contact thermistor output temperature, the data sampled in the above-mentioned certain mode is used. The calculation follows the formula of (contact thermistor temperature) = (non-contact thermistor temperature) + (temperature difference data). The above-described form of using the data sampled in the certain mode can correct the poor response of the non-contact thermistor because this data changes with time.

For example, during warm-up, the non-contact thermistor detects a low temperature. It is estimated that this temperature difference will increase with time, and the temperature of the non-contact thermistor will increase during the warm-up time.

[0101]

[Outside 2] Data will be added. Also, when copying

[0102]

[Outside 3] Data is added. However, this temperature difference is affected by the ambient temperature, the image ratio, and the like. These may be used for further correction. This correction may be performed by fuzzy reasoning.

For example, if the ambient temperature is low, the temperature difference is large, and if the image ratio is large, the temperature difference is large. First, the membership function is shown in FIG. Figure 2
6 (A) is the ambient temperature membership function, FIG. 26 (B).
Is a membership function indicating the image ratio (printing ratio). Then, in FIG. 26A, TL = low temperature [Temperature Low] TM = intermediate temperature [Temperature Medium] TH = high temperature [Temperature High] is shown. Further, in FIG. 26B, small = image ratio small = image ratio medium large = image ratio large. Further, FIG. 26C is a membership function showing a temperature difference coefficient by which the temperature difference is multiplied, and S = Small M = Middledle B = Big is shown.

FIG. 27 shows a fuzzy rule for determining the temperature difference coefficient.

Next, the temperature difference coefficient will be calculated as shown in FIG. 28 according to this fuzzy rule. (Rule 1) Ambient temperature TL and image ratio in th
en Temperature difference coefficient M (Rule 2) Ambient temperature TL and image ratio large th
en Temperature difference coefficient B (Rule 3) Ambient temperature TM and image ratio in th
en Temperature difference coefficient M (Rule 4) Ambient temperature TM and image ratio large th
en is the temperature difference coefficient M, and the intersection point of the ambient temperature x, the image ratio y and each membership function is obtained.

The values are μ12, μ23, ν13, ν24
MIN operation for each rule as
Membership functions of the temperature difference coefficient with the N value cut off from the head are shown by diagonal lines, horizontal lines, and vertical lines.

The center of gravity of these trapezoids is taken as the temperature difference coefficient.
FIG. 29 shows a flowchart of this fuzzy control. First, input the ambient temperature and the image ratio (step S
1 to S2). After that, for all the fuzzy rules, the degree of belonging to the fuzzy set of control quantities is calculated from the degree of belonging to the fuzzy set of state quantities according to the fuzzy rules described above (steps S3 to S4), and the maximum value of the set belonging to each rule is calculated. Calculate (step S5). Then, the most probable control amount is calculated by obtaining the center of gravity (step S6), the temperature difference coefficient is determined (step S7), and the temperature difference coefficient and the temperature difference are calculated.

[0108]

[Outside 4] By multiplying by, the estimated temperature difference is determined, and the temperature at the contact thermistor is estimated (step S8). That is,

[0109]

[Equation 1]

The contact thermistor temperature in the form

[0111]

[Outside 5] To estimate.

This estimated contact thermistor temperature

[0113]

[Outside 6] By controlling the fixing temperature, the temperature of the non-contact thermistor is corrected to control the temperature. Regarding the ON-OFF control of the contact type thermistor, it is turned OFF only after the initial data sampling.

In the above embodiment, the thermistor element is used as the non-contact temperature sensitive element, but other thermopile pyroelectric temperature detecting element may be used. By using these, it is possible to improve the delay in the thermal response time when using the thermistor element, and it is possible to cope with more rapid changes.

<Embodiment 10> Next, Embodiment 10 of the present invention.
Will be described with reference to FIGS. 30 and 32. FIG. 30 is a diagram showing a schematic configuration of a conventional image forming apparatus which is a basis of the apparatus of this embodiment. In FIG. 30, A is the main body of the apparatus, the original 402 placed on the original placing glass 401 is illuminated by a lamp 403, and its structure is a reflection mirror 404,
It is guided onto the photosensitive drum 408 by an optical system composed of 405, 406, 407 and the like. The lamp 403 and the mirrors 404, 405, and 406 respectively move in the direction of the arrow at a predetermined speed to operate the document 402. On the other hand, since the surface of the photosensitive drum 408 is also uniformly charged by the primary charger 409, the photosensitive drum 408 is also rotating in the direction of the arrow in the figure.
An electrostatic latent image corresponding to the original image is sequentially formed on the surface of the photosensitive drum 408. The electrostatic latent image formed on the photosensitive drum 408 is visualized (visualized) by the developing device 413 that contains toner arranged close to the photosensitive drum 408. The toner image on the surface of the photosensitive drum 408 formed as described above has a pre-transfer charger 412, a transfer / separation charger 411.
Of the photosensitive drum 4 by corona discharge by the transfer device 411a of
08 and the transfer / separation charger 411 is transferred to a sheet existing between the transfer device 411a. The toner existing on the photosensitive drum 408 is cleaned by the cleaning device 410, and then is prepared for charging, exposure and transfer.

In the image forming apparatus having the above structure, the paper 418 in the paper cassette 420 is conveyed by the paper feed roller group 419, and the photosensitive drum 408 and the transfer separation charger 411 are conveyed.
The toner image on the photosensitive drum 408 is transferred to the paper sheet that has reached between the transfer devices 411a of the above, and the paper sheet is separated from the photosensitive drum 408 by the corona discharge of the separator 411b of the transfer / separation charging device 411 and is conveyed to the conveying portion 415. The toner image on the sheet is fixed due to heating and the like by being conveyed by the fixing device 416 and the image formation is completed. During double-sided image formation or multiple-image formation, the flapper 421 provided in the paper discharge unit 423 is switched to convey the paper to the double-sided / multiple paper feed unit 417, and the re-feed roller group 42.
The sheet is re-fed by 2, and the image is formed again and discharged to the outside of the image forming apparatus.

Next, the auxiliary fixing means of the apparatus of this embodiment of the present invention will be described with reference to FIG. 31, and the control of the auxiliary fixing means will be described with reference to FIG. The same parts as those of the apparatus shown in FIG. 30 are designated by the same reference numerals and the description thereof will be omitted.
In FIG. 31, 425 (425a, 425b) is a residual heat power source as an auxiliary fixing means, and is an example using a metal roller for directly pinching and conveying the paper. A temperature control element 426 keeps the metal roller at an appropriate temperature. FIG. 32 is a control flowchart of the auxiliary fixing unit of the present invention.

After the main body of the image forming apparatus is turned on and warm-up is scheduled (the temperature of the main fixing device and the auxiliary fixing means is raised to a predetermined temperature), the user inputs the desired copy mode and the copy start key is turned on. Then, the paper 418 is fed by the paper feed roller group 419 (419a; pickup roller, 419b; feeding roller, 419c; retard roller) from the paper cassette 420 for image formation. When a sheet feeding signal is input to a microprocessor (not shown) provided in the image forming apparatus main body or the auxiliary fixing unit, the auxiliary fixing unit 425 is heated by the temperature control element 426 to a predetermined temperature for a predetermined time (T1 sec). Controlled. When the sheet feeding signal is transmitted a plurality of times (N times), the temperature control element 426 controls the temperature to a predetermined temperature for a predetermined time (T1 sec) after the Nth signal is transmitted.

<Embodiment 11> Next, an embodiment 11 of the present invention.
Will be described with reference to FIG. The same parts as those of the tenth embodiment are designated by the same reference numerals and the description thereof will be omitted.

This embodiment is different from the tenth embodiment in that the auxiliary fixing device is controlled by the user inputting the copy mode (the number of copies) and the copy start key. Figure 3
A description will be given according to the flowchart of FIG.

After the main body of the image forming apparatus is turned on and the predetermined warm-up is completed, the user inputs the desired copy mode (including the number of copies) and the copy key is turned on. Information such as the number of copies is input to a microprocessor (not shown) provided in the fixing unit, and the auxiliary fixing unit is controlled for a predetermined time (T0 sec). When the number of copies N is one or more, T0 + (N-1) T1sec (generally, the first copy takes an extra time longer than the time required for one continuous copy, so T1 is set so that T0 ≧ T1. The auxiliary fixing means is controlled to a predetermined temperature.

<Embodiment 12> Next, Embodiment 12 of the present invention.
Will be described with reference to FIG. The same parts as those of the tenth embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the present embodiment, the auxiliary fixing device controls the auxiliary fixing means by the output of the auxiliary fixing means and the paper detection sensor 424 provided in the paper feeding roller of the cassette 420. Description will be given according to the flowchart in FIG. 34. After the main body of the image forming apparatus is turned on and a predetermined warm-up is completed and the user inputs a desired copy mode and the copy key is turned on, the paper cassette 420 is turned on.
The paper is fed by the paper feed roller group 419 from FIG.
A signal is input to a microprocessor provided in the main body of the image forming apparatus or the auxiliary fixing unit in which a sheet is detected by the sheet detection sensor 424 shown in FIG.
The auxiliary fixing means is controlled to a predetermined temperature only for ec). When a plurality of signals (copies of a plurality of sheets) are input to the microprocessor, the auxiliary fixing unit is controlled to a predetermined temperature for a predetermined time (T1) from the last input signal.

<Embodiment 13> Next, Embodiment 13 of the present invention.
Will be described with reference to FIG. The same parts as those of the tenth embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the thirteenth embodiment, the paper detection sensor 424
Is a cassette 420 (420a; upper stage, 420b; lower stage)
Although it is provided on the feeding roller only for the sheet to be fed, the feeding roller and the cassette for the sheet to be re-fed when forming images on the same sheet a plurality of times such as double-sided image formation or multiple image formation. A sheet detection sensor 428 provided on the feeding roller that also serves as a feeding roller for the sheet fed from 420
It is also possible to control the auxiliary fixing means by the output of. Description will be given according to the flowchart of FIG. Figure 3
When the paper detection sensor 428 shown in 1 detects the paper,
A signal is input to the microprocessor provided in the main body of the image forming apparatus or the auxiliary fixing unit, and a predetermined time (T1s
The auxiliary fixing means is controlled to a predetermined temperature only for ec). When signals are input multiple times (when copying multiple sheets), a predetermined time (T1) from the last input signal
Only the auxiliary fixing means is controlled to a predetermined temperature. Next, control when forming a double-sided image and a multiplex image will be described. When forming a double-sided image or a multiplex image, after forming the image on the first side in FIG. 31, sheets are stocked in the double-sided / multiplex sheet feeding section 417 by switching the flapper 421, and then re-fed by the re-feed roller group 422. Image formation is performed. The sheet detection at this time is performed by the sheet detection sensor 427. When the paper detection sensor 427 detects a paper, the microprocessor detects the paper output. When the paper is detected by the output detection sensor 427, an output signal is transmitted to the microprocessor, and after a predetermined time, the paper detection sensor 428 detects the paper. However, the auxiliary fixing unit is controlled so as not to operate.

Although the tenth to thirteenth embodiments of the present invention have been described above, the auxiliary fixing means in the description is not limited to the metal roller, and various internal heating type, external heating type and the like are conceivable. Further, the installation position is not limited to the present invention as long as it is located between the sheet feeding path and the main fixing device. Further, it is more effective if the auxiliary fixing means is constituted by a device (flash etc.) capable of instantaneously adjusting the temperature. Further, as shown in FIG. 36, it is also possible to provide a residual heat source 430 and a temperature control element 431 as an auxiliary fixing means in the conveyance section 415. Further, it goes without saying that the paper detection in the twelfth and thirteenth embodiments can be separated from the paper detection at the time of jamming, and the auxiliary fixing means, like the main fixing means, operates for safety at the time of jamming. You are under control.

<Embodiment 14> Next, Embodiment 14 of the present invention.
Will be described with reference to FIGS. 37 and 38. FIG. 37 shows a copying machine 50 as an image forming apparatus to which the present invention is applied.
1 is shown. In the figure, in the copying machine 501,
Paper feed deck 502, photosensitive drum 503, optical unit 5
04, conveying means 505, thermal fixing device 506, transfer charger 507, registration roller pair 508, platen glass 50
9 is arranged.

The original D on the platen glass 509 is exposed by the optical unit 504 to reflect the reflected light on the photosensitive drum 503.
And a toner image is formed on the photosensitive drum 503.

On the other hand, the sheet P is fed from the paper feed deck 502 to the registration roller 508, fed to the photosensitive drum 503 at an appropriate timing, and the toner image formed on the photosensitive drum 503 is transferred by the transfer charger 507. The transferred sheet P is transferred to the heat fixing device 5 by the conveying unit 505.
The toner image is conveyed to 06 and the toner image is fixed.

FIG. 38 is a diagram showing the details from the conveying means 505 of the copying machine 501 to the heat fixing device 506.
The heat fixing device 506 includes a heat roller 510 having a heat source (heater) 512 therein and an elastic pressure roller 511. Below the heat fixing device 506, a suction fan 520 and a duct 521 extending to the conveying unit are arranged.
5 comprises a belt 522.

In the present invention, the heat of the heat fixing device 506 is drawn downward by the suction fan 520, and the duct 521 blows hot air onto the conveyor belt 522. Copy machine 501
Since the conveyor belt 522 also rotates by the pre-rotation during the warm-up, the conveyor belt 522 is uniformly warmed over the entire circumference at the end of the warm-up, and the passing paper is also warmed. Therefore, since the temperature of the paper passing through the heat fixing device becomes higher than usual, the amount of heat taken from inside the heat fixing for fixing the toner powder to the paper may be small, and the power consumption of the heat fixing device may be small. .

<Embodiment 15> Next, Embodiment 15 of the present invention.
Will be described with reference to FIGS. 39 to 41. The same parts as those of the fourteenth embodiment are designated by the same reference numerals and the description thereof will be omitted. 39 is a detailed front view of the transport unit 505 to the heat fixing device 506, FIG. 40 is a view taken in the direction of arrow A in FIG. 39,
41 is a sectional view taken along line BB in FIG.

The heat of the heat fixing device 506 is sucked by the suction fan 520.
By pulling it downwards from the duct 531 to the transport stay 533.
Enter through the lower openings 533a, 533b, 533c of
Passing through the inside, upper openings 533d and 533e of the transport stay
To the sheet P passing through the holes of the electrostatic adsorption belt 532 having a plurality of holes (FIGS. 39 and 4).
The arrow in the duct at 1 indicates the flow of hot air). Since the sheet P is sucked by the electrostatic attraction belt 532, it does not float up even if it receives hot air.

Therefore, since the paper passing through the heat fixing device is warmed and becomes higher in temperature than usual, the amount of heat taken from the heat fixing device for fixing the toner powder to the paper may be small, and the heat fixing device is not required. It consumes less power.

When the temperature of the conveyor belt 532 detected by the temperature detecting means 536 during the standby and warm-up (when not copying) exceeds a certain temperature, the operation of the suction fan 520 is stopped to save power.

<Example 16> Next, Example 16 of the present invention.
Will be described with reference to FIGS. 42 to 44. 42 is a detailed front view of the transport unit 505 to the heat fixing device 506, FIG. 43 is a view taken in the direction of arrow C in FIG. 42, and FIG.
7 is a sectional view taken along line EE in FIG.

The heat of the heat fixing device 506 is sucked by the suction fan 520.
By pulling it downwards from the duct 541 to the transport stay 543.
Enter through the lower openings 543a, 543b, 543c of
Passing through the inside, upper openings 543d and 543e of the transport stay
Transport belt 5 with multiple holes through
Hot air is blown onto the sheet P passing through the holes 42 (the arrows in the ducts in FIGS. 39 and 41 indicate the flow of hot air). The end portion of the sheet P has a feeding belt 542 that has the same feed speed as the conveying belt 542 and can be changed depending on the paper size.
Since the sheet P is conveyed by a and 544b, the sheet P does not float up even if it receives hot air from below.

Therefore, since the paper passing through the heat fixing device is warmed and becomes higher in temperature than usual, the amount of heat taken from the heat fixing property for fixing the toner powder to the paper may be small,
The heat fixing device consumes less power.

Also in this embodiment, when the temperature of the conveyor belt 532 exceeds a certain temperature during non-copying, the operation of the suction fan is stopped to save power.

[0140]

As described above, according to the first aspect of the present invention, when the transfer material is sandwiched by the fixing means, the heating means is always energized by a predetermined amount, and the fixing device is powered on. When the temperature of the post-fixing unit reaches a predetermined standby temperature, a signal indicating that the fixing operation is possible is output to an external image forming unit, and the temperature of the fixing unit is the fixing temperature at the time of fixing and the standby temperature. When the predetermined switching temperature set during the period is reached, the power supplied to the heating means is set to be lower than the power supplied from when the power is turned on until the standby temperature is reached. In addition, it is possible to provide a fixing device that can suppress insufficient fixing due to low temperature and that has small temperature ripple during fixing operation and low power consumption. Further, a fixing roller having a small size and a low heat capacity can be used without using a highly sensitive and expensive temperature sensor, and the warm-up time can be shortened and the speed can be increased at a low cost.

Further, according to the second invention of the present application, since the claw is moved by more than the claw width of the separation claw before the rotary body starts to rotate, it is possible to prevent damage to the rotary body due to the impression. The life of the rotating body can be extended.

Further, according to the third invention of the present application, since the releasing agent is held or supplied to the separating claw cleaning device to softly clean the separating claw, the fluororesin coating peeled off the tip of the separating claw. Can be prevented and the life of the separating claw can be extended.

According to the fourth invention of the present application, the temperature sensing element used in the contact method and the temperature sensing element used in the non-contact method are used in combination, and the temperature detected by the temperature sensing element in the non-contact method is a certain value or more. In this case, since the heating device is set to stop energizing, the contact type temperature sensor has the advantage of high reliability, and the non-contact type advantage is safety against roller scratches and mechanical It is possible to provide both of the advantages of safety against disconnection failure due to dynamic vibration, and to provide a safe and highly reliable fixing device.

Further, according to the fifth invention of the present application, the auxiliary fixing means is controlled so as to operate only during the first image formation,
Since it does not operate from the second image formation such as double-sided image formation or multiple image formation, it is possible to prevent a significant temperature rise of the transfer material on which the unfixed developer image is formed. It is possible to prevent a remarkable temperature rise in the machine caused by the heat of the material, and to suppress an increase in the temperature of the transfer material discharged after the image formation, which is discharged outside the image formation, to prevent the user from feeling uncomfortable. Moreover, since the power required for the auxiliary fixing unit is only required for the first image formation, extra power consumption can be suppressed.

Further, according to the sixth aspect of the present invention, the transfer material passing over the transfer material conveying means is warmed by utilizing the exhaust heat of the fixing device. Even with a small amount of heat, good fixability can be satisfied, and power consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a small fixing device having a low heat capacity according to a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing temperature / power control means of the apparatus shown in FIG.

FIG. 3 is a diagram showing the evaluation of the fixing roller temperature and the fixability for each copy when continuous paper is passed through the apparatus of FIG.

FIG. 4 is a block diagram showing temperature / power control means in an experimental example of the first embodiment.

FIG. 5 is a diagram showing the states of temperature control and power control during warm-up and copying in the experimental example of the first embodiment.

FIG. 6 is a diagram showing the evaluation of the fixing roller temperature and the fixability during continuous paper feeding when the conventional power / temperature control method is used.

FIG. 7 illustrates a schematic configuration of a fixing device according to a second exemplary embodiment of the present invention.

8 is a perspective view showing a schematic configuration of a separation claw in the apparatus of FIG.

FIG. 9 is a diagram for explaining the operation of the separating claw moving means shown in FIG. 8.

FIG. 10 is a perspective view showing the shape of a cam of the moving means shown in FIG.

FIG. 11 is a diagram showing a schematic configuration of an apparatus of Example 3 of the present invention.

12 is a perspective view showing a schematic configuration of a separation claw cleaning device in the device of FIG.

FIG. 13 is a diagram showing a schematic configuration of an apparatus of Example 4 of the present invention.

FIG. 14 is a diagram showing a schematic configuration of an apparatus of Example 5 of the present invention.

FIG. 15 is a diagram showing a schematic configuration of an Example 6 apparatus of the present invention.

16 is a perspective view showing a schematic configuration of a non-contact type temperature sensing element used in the apparatus of FIG.

FIG. 17 is a diagram showing the relationship between the roller temperature and the temperature detected by the temperature-sensitive element in the apparatus shown in FIG.

FIG. 18 is a diagram showing a temperature difference between the contact-type and non-contact-type temperature-sensitive elements used in the apparatus of FIG.

19 is a diagram showing a schematic configuration of a temperature control and abnormality detection circuit in the apparatus of FIG.

FIG. 20 is a diagram showing a schematic configuration of an apparatus of Example 7 of the present invention.

FIG. 21 is a diagram showing the relationship between the temperature detected by the contact-type and non-contact type temperature-sensitive elements and the number of passed sheets when a small-sized sheet is passed through the conventional example device.

22 is a diagram showing the relationship between the temperature detected by the contact-type and non-contact type temperature-sensitive elements and the number of passed sheets when small-sized sheets are passed through the apparatus in FIG. 20.

FIG. 23 is a diagram showing a schematic configuration of an apparatus of Example 8 of the present invention.

FIG. 24 is a diagram showing a schematic configuration of an apparatus of Example 9 of the present invention.

25 (A) is a diagram showing a temperature difference between a contact type and a non-contact type temperature sensing device used in the apparatus of FIG. 24, (B) is a diagram showing a temperature gradient of each temperature sensing device, and (C) is a diagram. [Fig. 3] is a diagram showing a temperature detected by each temperature sensitive element.

FIG. 26 is a diagram showing a membership function used in fuzzy inference for determining a temperature difference between temperature-sensitive elements in the apparatus shown in FIG. 24.

FIG. 27 is a diagram showing a fuzzy rule used for fuzzy inference for determining the temperature difference between the temperature-sensitive elements in the apparatus shown in FIG. 24.

28 is a diagram showing a method of obtaining a temperature difference coefficient by fuzzy inference for determining a temperature difference of a temperature sensitive element in the device shown in FIG. 24.

FIG. 29 is a flowchart showing an outline of fuzzy control for determining the temperature difference between the temperature sensitive elements in the apparatus shown in FIG. 24.

FIG. 30 is a diagram showing a schematic configuration of a conventional image forming apparatus which is a basis of an apparatus according to a tenth embodiment of the present invention.

FIG. 31 is a diagram showing a schematic configuration of an apparatus of Example 10 of the present invention.

FIG. 32 is a flow chart showing a method for controlling auxiliary fixing means in the apparatus shown in FIG. 31.

FIG. 33 is a flow chart showing a method for controlling auxiliary fixing means in Embodiment 11 of the present invention.

FIG. 34 is a flow chart showing a method for controlling auxiliary fixing means in Embodiment 12 of the present invention.

FIG. 35 is a flow chart showing a method for controlling auxiliary fixing means in Embodiment 13 of the present invention.

FIG. 36 is a diagram showing a schematic configuration of the embodiment apparatus when the position of the auxiliary fixing unit is changed.

FIG. 37 is a diagram showing a schematic configuration of a device according to a fourteenth embodiment of the present invention.

38 is a diagram showing a schematic configuration of a duct and a suction fan provided between the fixing device and the transfer material conveying means in the device shown in FIG. 37.

FIG. 39 is a diagram showing a schematic configuration of a device according to Example 15 of the present invention.

FIG. 40 is a view on arrow A in FIG. 39.

41 is a sectional view taken along line BB in FIG. 39.

FIG. 42 is a diagram showing a schematic configuration of an apparatus according to Example 16 of the present invention.

43 is a view on arrow C in FIG. 42. FIG.

44 is a sectional view taken along line EE in FIG. 42.

[Description of Reference Signs] 2 fixing roller (fixing means) 3 heater (heating means) 7 temperature detector (temperature detecting means) 8 pressure roller (fixing means) Tc fixing temperature Tp switching temperature Tw standby temperature 101 fixing roller (rotating body) ) 103 separation claw 201 fixing roller 204 separation claw 211 cleaning tool (cleaning device) 270 felt roller (means for supplying a release agent) 301 fixing roller (heating member) 303 heater (heating device) 304 thermistor (temperature sensitive element) T toner image (unfixed developer image) P recording material (transfer material) 416 fixing device (main fixing means) 418 paper (transfer material) 425 auxiliary fixing means 505 conveying means (transfer material conveying means) 506 fixing device 520 suction fan 521,531,541 Duct P sheet (transfer material)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical indication location G03G 15/00 110 7369-2H 15/16 21/00 111 (72) Inventor Shinsuke Ubayashi Tokyo 3-30-2 Shimomaruko, Ota-ku, Canon Inc. (72) Inventor Yasumi Yoshida 3-30-2 Shimomaruko, Ota-ku, Tokyo, Canon Inc. (72) Nobuo Nakazawa Sanzo Shimomaruko, Ota-ku, Tokyo Chome 30-2 Canon Inc. (72) Inventor Hideaki Ogasa 3-30-2 Shimomaruko Ota-ku, Tokyo Canon Inc. (72) Kenji Suzuki 3-30-2 Shimomaruko Ota-ku, Tokyo No. Canon Inc.

Claims (25)

[Claims] 1. A fixing unit configured to sandwich and convey a transfer material,
Heating means for heating the transfer material via the fixing means, temperature detecting means for detecting the temperature of the fixing means, and supplying a predetermined electric power to the heating means based on the temperature detected by the temperature detecting means. In a fixing device provided with a temperature / power control means for maintaining the heating means at a predetermined temperature, the temperature / power control means always energizes the heating means when a transfer material is sandwiched between the fixing means. When the temperature of the fixing means reaches a predetermined standby temperature lower than the fixing temperature at the time of fixing after powering on the fixing device, a signal indicating that the fixing operation is possible is sent to the external image forming means side. When the temperature of the fixing means reaches a predetermined switching temperature set between the fixing temperature and the standby temperature, the electric power supplied to the fixing means is supplied after the power is turned on. Fixing device characterized in that it is configured to lower power than power supplied by the time of machine temperature reached. 2. The switching temperature is set to be equal to or higher than the standby temperature.
The fixing device described in 1. 3. An image forming apparatus, comprising: a rotating body that nips and conveys a transfer material; and a separating claw that is disposed so as to contact the rotating body and that separates the transfer material. A moving means for reciprocating in the axial direction is provided, and the moving amount of the separating claw by the moving means is set to be larger than the width of the contact portion of the separating claw before the rotation of the rotating body. An image forming apparatus characterized by. 4. The image forming apparatus according to claim 3, wherein the rotating body is a fixing roller that fixes the unfixed developer image of the transfer material on the transfer material. 5. The image forming apparatus according to claim 4, wherein the fixing roller is an elastic roller whose surface is covered with an elastic body. 6. A fixing roller pair for nipping and conveying a transfer material,
The fixing claw is provided with a separation claw disposed so as to contact the surface of at least one of the pair of fixing rollers, and a cleaning device disposed so as to be capable of contacting the tip of the separation claw and cleaning the tip. The fixing device is provided with a means for holding or supplying a release agent to a portion of the tip of the cleaning device that comes into contact with the separation claw. 7. The fixing device according to claim 6, wherein a heat-resistant felt containing fluororubber, porous fluororesin, polyimide or polyamide-imide is attached to the tip of the cleaning device. 8. A felt roller or a web arranged so as to contact the tip of the cleaning device as the means for feeding the release agent to the tip of the cleaning device. Fixing device. 9. The means for supplying a release agent to the tip of the cleaning device also serves as a cleaning device for the fixing device,
9. The fixing device according to claim 6, wherein the cleaning device is arranged so as to be able to come into contact with and separate from the tip portion. 10. A heating member arranged in contact with an unfixed developer image on a transfer material, an electric heating element arranged in the heating member, and a temperature of the heating member. In a fixing device having a temperature-sensitive element for detecting, at least two temperature-sensitive elements are arranged in the vicinity of the heating member,
At least one of them is in non-contact with the heating member, and energization of the electric heating element is set so as to stop when the signal of the temperature-sensitive element arranged in the non-contact exceeds a certain value. The fixing device is characterized in that 11. The heating member is controlled so as to maintain a predetermined set temperature, and the set temperature is set so as to be arranged in a non-contact manner and to be changed by a signal of a temperature sensing element. The fixing device according to claim 10. 12. The temperature detected by a temperature-sensitive element arranged in a non-contact manner is set to be corrected by the temperature detected by a temperature-sensitive element arranged so as to contact the heating member. The fixing device according to claim 10. 13. An image forming portion for forming an unfixed developer on a transfer material, a main fixing means for heating or pressurizing the transfer material, and the transfer before the transfer material is conveyed to the main fixing means. In an image forming apparatus provided with auxiliary fixing means for holding the temperature of the material within a predetermined temperature range in advance, the auxiliary fixing means is configured such that after the fixing operation is once performed by the main fixing means, the transfer material is a double-sided image. An image forming apparatus, which is set so as not to operate when being fed again to the image forming unit for formation or multiple image formation. 14. The image forming apparatus according to claim 13, wherein the auxiliary fixing unit is set to operate in association with a sheet feeding timing of the sheet feeding apparatus. 15. The image according to claim 13, wherein the auxiliary fixing unit is set so as to be controlled based on an output of a transfer material detecting unit provided in the transfer material transporting path. Forming equipment. 16. The image forming apparatus according to claim 13, wherein the auxiliary fixing unit is set so as to be controlled based on a copy mode switching or a copy start signal input. 17. An image forming means for forming an unfixed developer image on a transfer material, a fixing device for fixing the unfixed developer image by heating and pressurizing the transfer material, and the fixing from the image forming means. In an image forming apparatus including a transfer material conveying unit that guides the transfer material to the apparatus, a suction fan disposed below the fixing device and the suction fan communicates with the transfer material from below the fixing device. An image forming apparatus, comprising: a duct extending below a conveying unit. 18. The image forming apparatus according to claim 17, wherein the transfer material transporting means is a belt-shaped transporting means. 19. The image forming apparatus according to claim 18, wherein the belt has a large number of holes for ventilation. 20. The image forming apparatus according to claim 19, wherein the belt is formed of an electrostatic attraction member. 21. The image forming apparatus according to claim 19, wherein the transfer section of the transfer material transfer means is provided with a pressing member for pressing and transferring the end of the transfer material. 22. The pressing member is formed of a belt, and the feeding speed of the belt is set to be the same as the conveying speed of the belt for conveying the transfer material. Image forming device. 23. The pressing member is arranged movably in the width direction depending on the size of the transfer material.
1. The image forming apparatus according to 1. 24. The method according to claim 17, further comprising means for intermittently controlling the drive of the suction fan.
The image forming apparatus according to any one of 3 above. 25. The belt temperature detecting means of the transfer material conveying means is provided.
The image forming apparatus according to one of the above.