JPH11194836A - Electric conduction control means, fixing device, and image forming device equipped with them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric conduction control means which can secure an insulation interval between a primary and a secondary circuit while reducing the cost, and a fixing device, or an image forming device equipped with them. SOLUTION: According to a temperature detected by a thermistor temperature detecting sensor 113, and analog information outputted from the thermistor temperature detecting sensor 113 is converted by an analog-digital converter 110 into digital information, which is transmitted to a CPU 120 through a capacitor 115, a power source main transformer 101, and a capacitor 120.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply control means for controlling power supply from a commercial power supply to a heating means, a fixing device, and an image forming apparatus having the same.

[0002]

2. Description of the Related Art As an example of the power supply control means, a power supply control circuit shown in FIG.
It has been put to practical use. FIG. 10 is a schematic circuit diagram showing a schematic configuration of the energization control circuit.

In the power supply control circuit, the commercial power supply 30
1 is connected to a heating element 307 provided in the heating means 305 via a drive circuit 311 and to a switching power supply 302.

The switching power supply 302 is set so as to supply DC power to a CPU 320 which is an intermittent operation control means which is insulated from the commercial power supply 301 by a transformer.
0 controls the driving of the heating element 307 by the drive circuit 311 as the intermittent means, and sets the temperature of the heating means 305.

In the CPU 320, analog information from the temperature detector 306 obtained by detecting the temperature of the temperature detector 306 is converted into digital information in an analog-to-digital converter 310 (hereinafter, referred to as an A / D conversion circuit 310). After the conversion, it is set to be input through the pulse transformer 313.

That is, the CPU 320 is set so as to control the drive circuit 311 based on the digital information to set the temperature of the heating means 305.

Next, a ceramic heater 400 as an example of the heating means 305 will be described with reference to FIG.
FIG. 11 is a front and rear view showing a schematic configuration of the ceramic heater 400.

The ceramic heater 400 has conductive patterns 403 and 404 on one surface 401 of a thin plate-like substrate.
And a second circuit on which a chip thermistor 402 as a temperature detector is mounted, and the other surface 405 of the substrate includes resistance patterns 407 and 408 as heating elements.
The following circuit is assembled, so that the resistance patterns 407 and 4
When a voltage is applied to both ends of the substrate 08, heat is generated and a heating step is performed.

The one surface 401 is provided with a low voltage secondary circuit, and the other surface 405 is provided with a high voltage primary circuit. And it is necessary to take a safe value for the distance between the secondary circuit and
Accordingly, the width of the substrate is required to be larger than the width of the ceramic heater which is originally required, and the number of substrates to be taken from a fixed size is reduced, so that an expensive ceramic heater may be obtained.

Therefore, in the related art, since the primary circuit and the secondary circuit are electrically separated and insulated by the pulse transformer 313, it is necessary to re-establish the interval between the primary circuit and the secondary circuit. Is gone.

[0011]

However, in the prior art, in order to secure an insulation interval between the primary circuit and the secondary circuit, a new pulse transformer is provided between the primary circuit and the secondary circuit. Since it is necessary to add an insulating element such as the above, it has been difficult to reduce the cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an energization control unit, a fixing device, and an image forming apparatus including the same, which can secure an insulation interval between a primary circuit and a secondary circuit while reducing costs. And

[0013]

According to the present application, the above-mentioned object is an energization control means for controlling energization from a commercial power supply to a heating element, which is capable of intermittently energizing the heating element from a commercial power supply. Intermittent means, intermittent operation control means for controlling the intermittent operation of the energization by the intermittent means to adjust the temperature of the heating element, and power transformer means arranged to insulate the commercial power supply from the intermittent operation control means. A power supply control means for converting the analog information output from the temperature detector into digital information in accordance with the detected temperature of the temperature detector for detecting the temperature of the heating means having the heating element; This is achieved by the first invention including a digital information transmitting unit that transmits the digital information to the intermittent operation control unit via the transformer unit.

Further, according to the present application, the above object is achieved in the first invention according to the present application, wherein transmission of digital information from the conversion means to the intermittent operation control means is synchronized with the switching frequency of the power transformer means. The present invention is also achieved by the second invention in which the setting is performed in such a manner.

Further, according to the present application, the above object is achieved in the first invention or the second invention according to the present application, wherein the conversion means is provided with a plurality of mutually switchable channels, and Any of the channels is connected to the temperature detector, and the remaining channels are connected to the power transformer means, inputting analog information to the channels connected to the temperature detector and connecting to the channels connected to the power transformer means. This is also achieved by the third invention in which the setting is made such that the input of the analog information is performed alternately.

According to the present application, the above object is achieved by any one of the first to third inventions according to the present application.
The intermittent operation control means is achieved by a fourth invention in which the intermittent operation of the power supply from the commercial power supply to the heating element by the intermittent means is controlled in accordance with the digital information output from the conversion means to adjust the heat generation temperature of the heating element. Is done.

Further, according to the present application, the above object is achieved by a heating unit while passing a sheet-shaped recording medium carrying an unfixed image between a fixing member and a pressing member pressed against each other. A fixing device for heating a recording medium, comprising a temperature detector of a heating unit, wherein the heating unit is provided with a heating element that generates heat when energized from a commercial power supply, and the heating element is a first invention according to the present application. The present invention is also achieved by the fifth invention in which the power supply from the commercial power supply is controlled by the power supply control means described in (1).

According to the present application, the above object is achieved according to the fifth aspect of the present invention, wherein the transmission of the digital information from the conversion means to the intermittent operation control means is synchronized with the switching frequency of the power transformer means. The present invention is also achieved by the sixth invention in which the setting is made so as to be performed.

Further, according to the present application, the above object is achieved in the fifth or sixth invention according to the present application, wherein the conversion means is provided with a plurality of mutually switchable channels, and Any of the channels is connected to the temperature detector, and the remaining channels are connected to the power transformer means, inputting analog information to the channels connected to the temperature detector and connecting to the channels connected to the power transformer means. This is also achieved by the seventh invention in which the setting is made such that the input of the analog information is performed alternately.

According to the present application, the above object is achieved by any one of the fifth to seventh inventions according to the present application.
The intermittent operation control means also controls the intermittent operation of energization from the commercial power supply to the heating element by the intermittent means in accordance with the digital information output from the conversion means to adjust the heat generation temperature of the heating element. Achieved.

Further, according to the present application, the above object is to provide an image forming apparatus for forming an image corresponding to external image information on a sheet-shaped recording medium. The present invention is also achieved by a ninth invention that includes the energization control means described above and the fixing device according to the fifth invention of the present application.

According to the present application, the above object is achieved in the ninth invention according to the present application, wherein the transmission of digital information from the conversion means to the intermittent operation control means is synchronized with the switching frequency of the power transformer means. The present invention is also achieved by the tenth invention in which the setting is made so as to be performed.

Further, according to the present application, the above object is achieved in the ninth or tenth invention according to the present application, wherein the conversion means is provided with a plurality of mutually switchable channels, and Any of the channels is connected to the temperature detector, and the remaining channels are connected to the power transformer means, inputting analog information to the channels connected to the temperature detector and connecting to the channels connected to the power transformer means. This is also achieved by the eleventh invention in which the setting is made such that the input of the analog information is performed alternately.

Further, according to the present application, the above object is achieved in the ninth to eleventh inventions according to the present application, wherein the intermittent operation control means performs the intermittent operation in accordance with the digital information output from the conversion means. The invention is also achieved by a twelfth invention in which the intermittent operation of energization from the commercial power supply to the heating element by means is controlled to adjust the heating temperature of the heating element.

That is, according to the first aspect of the present invention, after the analog information output from the temperature detector is converted into digital information by the converter in accordance with the detected temperature of the temperature detector, and then output. The digital information transmitting means transmits the digital information to the intermittent operation control means via the power transformer means.

In the second invention according to the present application,
The transmission of the digital information from the conversion means to the intermittent operation control means is performed in synchronization with the switching frequency of the power transformer means.

Further, in the third invention according to the present application, the input of analog information to the channel connected to the temperature detector and the input of analog information to the channel connected to the power transformer are alternately performed. Done in

Further, in the fourth invention according to the present application,
The intermittent operation control means controls the intermittent operation of the power supply from the commercial power supply to the heating element by the intermittent means in accordance with the digital information output from the conversion means, and adjusts the heat generation temperature of the heating element.

Further, in the fifth invention according to the present application, the converting means converts the analog information output from the temperature detector into digital information in accordance with the detected temperature of the temperature detector provided in the fixing device. After the conversion and output, the digital information transmitting means transmits the digital information to the intermittent operation control means via the power transformer means.

In the sixth invention according to the present application,
The transmission of the digital information from the conversion means to the intermittent operation control means is performed in synchronization with the switching frequency of the power transformer means.

Further, according to the seventh aspect of the present invention, analog information is input to a channel connected to a temperature detector provided in a fixing device and analog information is input to a channel connected to a power transformer. Input of information is performed alternately.

In the eighth invention according to the present application,
The intermittent operation control means controls the intermittent operation of the power supply from the commercial power supply to the heating element by the intermittent means in accordance with the digital information output from the conversion means, and adjusts the heat generation temperature of the heating element.

Further, according to the ninth invention of the present application, the analog information output from the temperature detector is converted according to the temperature detected by the temperature detector of the fixing device provided in the image forming apparatus. After converting the digital information into digital information and outputting the digital information, the digital information transmitting means transmits the digital information to the intermittent operation control means via the power transformer means.

In the tenth invention according to the present application,
The transmission of the digital information from the conversion means of the power supply control means provided in the image forming apparatus to the intermittent operation control means is performed in synchronization with the switching frequency of the power transformer means.

Further, in the eleventh invention according to the present application, analog information is input to a channel connected to a temperature detector of a fixing device provided in the image forming apparatus, and the analog information is connected to a power transformer. The input of analog information to the selected channel is performed alternately.

In the twelfth invention according to the present application, the intermittent operation control means of the energization control means provided in the image forming apparatus uses the intermittent means in accordance with the digital information output from the conversion means. The intermittent operation of energization from the commercial power supply to the heating element is controlled to adjust the heating temperature of the heating element.

[0037]

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

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a laser printer 1 (hereinafter, abbreviated as printer 1), which is a preferred example of the image forming apparatus according to the present embodiment.

The printer 1 is an image forming apparatus that forms an image on a recording medium in accordance with image information provided from an external output device such as a host computer installed outside the main body of the printer 1.

As shown in FIG. 1, the printer 1 has a drum-shaped latent image carrier 2 for carrying an electrostatic latent image corresponding to image information from an external output device, and an outer peripheral surface of the latent image carrier 2. Developing device 3 for visualizing the formed electrostatic latent image with a developer
A transfer roller 4 for transferring the visible image formed on the outer peripheral surface by the developing process of the developing device 3 onto a recording medium; and a fixing device 5 for performing a fixing process on the recording medium carrying the unfixed image.
Various devices such as the latent image carrier 2 and the developing device 3 are generally controlled by an engine controller 6 mounted on the main body of the printer 1.

That is, in the printer 1, in response to input of image information and the like from the external output device to the printer 1, the outer peripheral surface of the latent image carrier 2 is moved by the primary charging roller 7 disposed therearound. It is charged to a specified potential distribution.

On the other hand, the laser scanner unit LY raster-scans the laser La in response to the image information from the external output device.
The laser La raster-scanned from the laser beam is refracted by the folding mirror 8 and irradiates a charged portion of the outer peripheral surface of the latent image carrier 2 so that an electrostatic latent image corresponding to the image information is obtained. An image is formed at the site.

Next, the electrostatic latent image formed on the outer peripheral surface of the latent image carrier 2 is visualized by a developer from the developing device 3 and is then detachably supported by the main body of the printer 1. A recording medium formed on the outer peripheral surface of a recording medium conveyed from a paper cassette 9 (hereinafter, abbreviated as a cassette 9) to a transfer area formed between the latent image carrier 2 and the transfer roller 4 The visual image is transferred by the transfer roller 4.

In the present embodiment, first, the paper feed roller 1 rotatably supported near the cassette 9
0, the paper is taken out of the cassette 9 and then fed from the paper feed roller 10 to the transport roller 11 rotatably supported at a position on the upstream side in the recording medium transport direction.

Next, the recording medium having reached the transport roller 12 is transported by the transport roller 11 from the transport roller 11 to a paper feed sensor 12 arranged at a position upstream in the recording medium transport direction.

The feed sensor 12 conveys the recording medium to the transfer area so that the leading end of the image forming portion of the recording medium and the leading end of the image forming portion on the outer peripheral surface of the latent image carrier 2 are synchronized. The transfer timing of the recording medium to the transfer area is set.

Further, the recording medium on which the transfer processing has been performed is subjected to fixing processing by heating and pressurizing in the fixing device 5, and then is discharged by a discharge roller 13 rotatably supported by the main body of the printer 1. The image forming process ends when the sheet is discharged onto the sheet 14.

Next, the fixing device 5 will be described with reference to FIG. FIG. 2 is a schematic sectional view showing a schematic configuration of the fixing device 5.

As shown in FIG. 2, the fixing device 5 includes a ceramic heater 111 as a heating means, an endless film 16 as a fixing member, and a cylindrical or substantially cylindrical rotatable pressure roller as a pressure member. 17 and ceramic heater 11
1 and a holder 18 for guiding the moving direction of the film 16.

The ceramic heater 111 is shown in FIGS.
As shown in FIG. 2, a heating resistor 112 as a heating element that generates heat when energized by a commercial power supply (not shown) is provided on one surface of a substrate 111A on a thin plate mainly composed of ceramics. A thermistor temperature sensing sensor 113 (hereinafter, abbreviated as the thermistor 113), which is a temperature detector, is disposed on the other surface in contact with the other surface, and the one surface is for protecting the film 16 from friction with the film 16 or the like. The protective layer 111B is covered.

FIG. 3 shows the ceramic heater 111.
1 is a partially transparent perspective view showing a schematic configuration of FIG.

The film 16 has an inner peripheral length of the holder 18.
The film 16 is loosely fitted to the holder 18 in a tensionless state.

The pressing roller 17 has a cylindrical cored bar 17A mainly composed of a metal such as aluminum, and an outer peripheral surface covered with a coating layer 17B mainly composed of silicone rubber or the like.

The pressing roller 17 is pressed against one surface of the ceramic heater 111 from a pressing mechanism (not shown) provided in the main body of the printer 1 so as to be in pressure contact with the film 16. A nip portion N through which a recording medium carrying an unfixed image is passed is formed between the recording medium and the film 16.

Further, in the present embodiment, the pressing roller 17 is driven in a prescribed direction by applying a driving force to a core 17A from a driving mechanism (not shown) provided in the main body of the printer 1. Thus, the film 16 pressed against the pressure roller 17 moves in the guide direction of the holder 18 following the rotation of the pressure roller 17.

That is, during the fixing process, the recording medium carrying the unfixed image is passed through the nip N by the film 16 and the pressure roller 17 pressed against each other.
By heating the ceramic heater 111, the unfixed image melts and penetrates into the recording medium, so that an image corresponding to image information from an external output device is recorded on the recording medium.

Next, an example of an energization control circuit which preferably shows the energization control means of this embodiment will be described with reference to FIG. FIG. 4 is a schematic circuit diagram showing a schematic configuration of the energization control circuit.

In the power supply control circuit, reference numeral 101 denotes a power supply main transformer of a switching power supply as power supply transformer means, 102 denotes an auxiliary power supply winding of the power supply main transformer 101, 103 denotes a starting resistor, 123 denotes a secondary side winding, 1
Reference numeral 04 denotes a main power supply winding of the power supply main transformer 101, which turns on a current flowing through the main power supply winding 104.
/ OFF is intermittently switched by the switching element 105 to adjust the power transmitted to the secondary side.

That is, in the power supply control circuit, when the power is output from the commercial power supply 117, the capacitor 107 is charged via the starting resistor 103, and the power control I
The power supply rises when the voltage of C124 reaches the starting voltage.

Therefore, the switching element 105 is turned ON / OFF.
When turned off, the current flowing through the main power supply winding 104 is adjusted, and power is transmitted to the secondary side.

At the time of power transmission to the secondary side, the capacitor 107 is charged from the auxiliary power supply winding 102 via the diode 106, so that the voltage value according to the input voltage and the load on the secondary side is obtained. Is maintained.

Further, in the current supply control circuit, the voltage of the regulator 108 is stabilized to a constant value smaller than the voltage stored in the capacitor 107. If the temperature of the ceramic heater 111 is constant, the voltage applied to the thermistor 113 is The voltage is set to be divided into the resistance value of the resistor 114 and the resistance value of the thermistor 113.

Therefore, in this embodiment, the voltage applied to the thermistor 113 changes as the resistance of the thermistor 113 changes as shown in FIG. 5 according to the temperature change of the ceramic heater 111. Digital information output from an analog-to-digital converter 110 (hereinafter, referred to as an A / D conversion circuit 110) as a conversion unit changes.

FIG. 5 is a graph showing the temperature dependence of the resistance value of the thermistor 113.

Therefore, in the present embodiment, the digital information output from the A / D conversion circuit 110 has a frequency different from the switching frequency of the switching, the capacitor 115, the power supply main transformer 101, and the capacitor 129 on the secondary side. CP as intermittent operation control means
C transmitted to U120 and inputted with the digital information
The PU 120 controls the drive circuit 116 as an intermittent means in accordance with the digital information to set the temperature of the ceramic heater 111.

As described above, in this embodiment, the A / D conversion circuit 110 converts the analog information output from the thermistor 113 into digital information according to the temperature detected by the thermistor 113. Capacitor 115 serving as a digital information transmitting means, a power supply main transformer 101 and a capacitor 1 serving as a digital information transmitting means
Since the digital information is transmitted to the CPU 102 via the CPU 20, an insulation such as a pulse transformer is newly provided between the primary circuit and the secondary circuit to secure an insulation interval between the primary circuit and the secondary circuit. The insulation interval can be ensured without adding an element, so that the cost can be reduced.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. Since the schematic configuration of the fixing device and the image forming apparatus in the present embodiment is the same as that of the first embodiment,
Description will be omitted in place of the drawings of FIGS.

FIG. 6 is a schematic circuit diagram showing a schematic configuration of an energization control circuit, which is an example suitably showing the energization control means in the present embodiment. In this embodiment, the A / D converter as the conversion means is used. The circuit 210 is provided with a plurality of mutually switchable channels (not shown), and each channel is switched by an analog switch (not shown) to be used for inputting analog information from the outside.

In the present embodiment, the description will be omitted by giving the same reference numerals to the portions common to FIG. 4 and FIG.

In this embodiment, by switching the analog switch, the thermistor 113 is switched to an arbitrary one of a plurality of channels (hereinafter referred to as channel 1) in accordance with the temperature detected by the thermistor 113.
The analog information output from is input and any of the remaining channels (hereinafter, referred to as
Called channel 2. ) Is set so that analog information, which is a voltage output from an auxiliary power supply (not shown), is input thereto.

That is, in the present embodiment, the A / D conversion circuit 210 sets the channel 1 and the channel 2 at regular intervals.
Are set to be switched by an analog switch.

Further, as shown in FIG. 7, in the power supply main transformer 101, the auxiliary power supply voltage in the power supply main transformer 101 tends to increase as the input voltage increases. When the auxiliary power supply voltage is high, it is determined that the input voltage is high. Therefore, the ceramic heater 11 is used to prevent excessive power from being supplied to the ceramic heater 111 in a short time.
1 is set so as to limit the power supplied thereto.

FIG. 7 is a graph showing the correspondence between the input voltage and the auxiliary power supply voltage.

As described above, in the present embodiment, even if the voltage of the auxiliary power supply in the power supply main transformer 101 fluctuates, the CPU 120 serving as the intermittent operation control means assembled on the secondary side, Since the amount of power supply to the ceramic heater 111 according to the digital information from the A / D conversion circuit 210 is calculated, the analog information output from the thermistor 113 is not erroneously detected according to the temperature detected by the thermistor 113. Since the correct detection temperature can be read, there is no need to provide a voltage regulator, etc.
Thus, cost can be reduced.

(Third Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. Note that the schematic configurations of the power supply control unit, the fixing device, and the image forming apparatus in the present embodiment are the same as those in the first embodiment, and thus description thereof is omitted in place of the drawings of FIGS.

Hereinafter, in the present embodiment, the switching frequency described in the first embodiment is referred to as a frequency F1.

In the present embodiment, the thermistor 113
The conversion of the analog information output from the thermistor 113 into digital information by the A / D conversion circuit 110 according to the detected temperature is set to be performed in synchronization with the frequency F1 as shown in FIG. .

FIG. 8 shows the switching element 109
It is a timing chart figure at the time of performing N / OFF.

That is, in the present embodiment, when the digital information output from the A / D conversion circuit 110 is "1", the switching element 109 is set to be turned on / off.

Therefore, ON / O of the switching element 109
The ON / OFF signal for the FF is supplied to the capacitor 115, the power supply main transformer 101, and the secondary-side capacitor 129.
Is transmitted to the secondary circuit via the CPU 120, so that the digital information is input to the CPU 120
Determines that the digital information is "1".

On the other hand, when the digital information output from the A / D conversion circuit 110 is "0", the switching element 109 is set so as not to be turned on / off.

Therefore, ON / O of switching element 109
When the FF is not performed, the A / D conversion circuit 11
Since the digital information from 0 is not transmitted to the CPU 120, the CPU 120 determines that the digital information is "0".

Further, as shown in FIG. 9, in order to suppress the influence of noise due to input / output and transmission of information, in this embodiment, the switching element 109 is turned on / off.
Only one of ON / OFF in the switching waveform of the ON / OFF signal for ON (only the ON portion in FIG. 9) is used, and the switching element 109 is changed from ON to OFF.
In other words, the influence of the noise is suppressed by avoiding the timing at which the switching element 109 is turned on from the off state.

FIG. 9 is a timing chart when the switching element 109 is turned ON / OFF while suppressing the influence of the noise.

As described above, in this embodiment, the same effects as those of the first embodiment can be obtained, and the switching of the ON / OFF signal for turning ON / OFF the switching element 109 can be achieved. ON / O in waveform
Only one of the FFs (only the ON portion in FIG. 8) is used, and the switching element 109 is turned off from ON.
Alternatively, by avoiding the timing when the switching element 109 is turned on from the off state, there is an advantage that the influence of the noise can be reduced.

[0087]

As described above, according to the first aspect of the present invention, the conversion means converts the analog information output from the temperature detector according to the detected temperature of the temperature detector. After converting the digital information into digital information and outputting the digital information, the digital information transmitting means transmits the digital information to the intermittent operation control means via the power transformer means, so that an insulation interval between the primary circuit and the secondary circuit is secured. The insulating interval can be secured without newly adding an insulating element such as a pulse transformer between the primary circuit and the secondary circuit,
Thus, cost can be reduced.

According to the second aspect of the present invention, the transmission of the digital information from the conversion means to the intermittent operation control means is performed in synchronization with the switching frequency of the power transformer means. In order to secure the insulation interval between the circuit and the secondary circuit, the insulation interval can be secured without newly adding an insulating element such as a pulse transformer between the primary circuit and the secondary circuit, Thus, cost can be reduced.

Further, according to the third invention of the present application,
Since the input of the analog information to the channel connected to the temperature detector and the input of the analog information to the channel connected to the power transformer are alternately performed, the power supply voltage of the power transformer can be constantly detected. Thus, the input voltage can be easily determined.

According to the fourth aspect of the present invention, the intermittent operation control means controls the intermittent operation of the power supply from the commercial power supply to the heating element by the intermittent means in accordance with the digital information output from the conversion means. Since the heating temperature of the heating element is adjusted by controlling, it is possible to suppress the disturbance of the heating temperature due to the influence of noise due to input / output and transmission of information.

Further, according to the fifth invention of the present application,
After converting the analog information output from the temperature detector according to the detected temperature of the temperature detector included in the fixing device into digital information and outputting the digital information, the digital information transmitting unit transmits the digital information via the power transformer unit. Since the digital information is transmitted to the intermittent operation control means, an insulating element such as a pulse transformer is newly provided between the primary circuit and the secondary circuit in order to secure an insulation interval between the primary circuit and the secondary circuit. Thus, it is possible to provide the fixing device in which the insulation interval can be ensured without adding the fixing device, and the cost is reduced.

According to the sixth aspect of the present invention, the transmission of the digital information from the conversion means to the intermittent operation control means is performed in synchronization with the switching frequency of the power transformer means. According to the seventh invention of the present application, the input of analog information to the channel connected to the temperature detector provided in the fixing device and the input of analog information to the channel connected to the power transformer are performed. The insulation is performed alternately without adding a new insulating element such as a pulse transformer between the primary circuit and the secondary circuit in order to secure an insulation interval between the primary circuit and the secondary circuit. An interval can be ensured, so that a fixing device with reduced cost can be provided.

According to the eighth aspect of the present invention, the intermittent operation control means controls the intermittent operation of the power supply from the commercial power supply to the heating element by the intermittent means in accordance with the digital information output from the conversion means. Since the heating temperature of the heating element is controlled by controlling the power supply voltage, the power supply voltage of the power supply transformer can be constantly detected, so that it is possible to provide a fixing device in which input voltage determination is simplified.

Further, according to the ninth invention of the present application, the analog information output from the temperature detector according to the temperature detected by the temperature detector of the fixing device provided in the image forming apparatus is converted. Is converted to digital information and output, and then the digital information transmitting means transmits the digital information to the intermittent operation control means via the power transformer means.
In order to secure the insulation interval between the primary circuit and the secondary circuit, the insulation interval can be secured without newly adding an insulating element such as a pulse transformer between the primary circuit and the secondary circuit. Accordingly, it is possible to provide an image forming apparatus including a fixing device with reduced cost.

According to the tenth aspect of the present invention, the transmission of the digital information from the conversion means of the power supply control means provided to the image forming apparatus to the intermittent operation control means is performed by switching the power supply transformer means. Since it is performed in synchronization with the frequency, a new insulating element such as a pulse transformer is newly added between the primary circuit and the secondary circuit to secure an insulation interval between the primary circuit and the secondary circuit. Therefore, it is possible to provide an image forming apparatus including a fixing device that can secure the insulation interval and reduce cost.

Further, according to the eleventh aspect of the present invention, the analog information is input to the channel connected to the temperature detector of the fixing device provided in the image forming apparatus, and the analog information is connected to the power transformer means. Since the input of analog information to the channel is performed alternately, a pulse transformer or the like is newly provided between the primary circuit and the secondary circuit in order to secure an insulation interval between the primary circuit and the secondary circuit. It is possible to provide the image forming apparatus including the fixing device in which the insulating interval can be secured without adding the insulating element described above, and the cost is reduced.

According to the twelfth invention of the present application,
The intermittent operation control unit of the energization control unit provided in the image forming apparatus controls the intermittent operation of energization from the commercial power supply to the heating element by the intermittent unit in accordance with the digital information output from the conversion unit, thereby generating heat of the heating element. Since the temperature is adjusted, the power supply voltage of the power transformer means can always be detected,
It is possible to provide an image forming apparatus including a fixing device in which input voltage determination is simplified.

[Brief description of the drawings]

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

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

FIG. 3 is a partially transparent perspective view showing a schematic configuration of the ceramic heater shown in FIG. 2;

FIG. 4 is a schematic circuit diagram illustrating a schematic configuration of an energization control unit according to the first embodiment of the present application.

5 is a graph showing the temperature dependence of the resistance value of the thermistor temperature sensing sensor shown in FIG.

FIG. 6 is a schematic circuit diagram illustrating a schematic configuration of an energization control unit according to a second embodiment of the present application.

FIG. 7 is a graph showing a correspondence between an input voltage and an auxiliary power supply voltage in the second embodiment according to the present application.

FIG. 8 is a timing chart when a switching element is turned on / off in a third embodiment according to the present application.

FIG. 9 shows ON / OF of a switching element while suppressing the influence of noise in the third embodiment according to the present application.
It is a timing chart figure at the time of performing F.

FIG. 10 is a schematic circuit diagram showing a schematic configuration of an example of a conventional energization control means.

11 is a front and rear view of a ceramic heater as an example of the heating unit shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser printer (image forming apparatus) 5 Fixing device 16 Film (fixing body) 17 Pressure roller (Pressing body) 18 Holder 101 Power supply main transformer (Power supply transformer means) 102 Auxiliary power supply winding 103 Starting resistance 104 Main power supply winding Reference Signs List 105 switching element 106 diode 107 capacitor 108 regulator 110 analog-digital converter (conversion means) 111 ceramic heater (heating means) 112 heating resistor (heating element) 113 thermistor temperature sensing sensor (temperature sensing element) 115 capacitor (digital information transmission) Means) 120 Capacitor (digital information transmitting means) 124 Power supply control IC 210 Analog-digital converter (converting means) 301 Commercial power supply 302 Switching power supply 305 Heating means 307 Heating element 3 0 analog-digital converter (conversion means) 311 drive circuit (intermittent means) 313 pulse transformer 320 CPU (intermittent operation control means) 400 ceramic heater (heating means) 402 chip thermistor (temperature detector) 407 resistance pattern (heater) 408 Resistance pattern (heating element) 111A Substrate 111B Protective layer N Nip

Claims (12)

[Claims] 1. An energization control means for controlling energization from a commercial power supply to a heating element, comprising: an intermittent means capable of intermitting energization from the commercial power supply to the heating element; Intermittent operation control means for adjusting the heat generation temperature of the heating element, and power supply control means comprising power transformer means arranged to insulate the commercial power supply and the intermittent operation control means. A converter for converting analog information output from the temperature detector into digital information in accordance with the detected temperature of the temperature detector to be detected and outputting the digital information; and transmitting the digital information to an intermittent operation controller via a power transformer. Power supply control means, comprising: 2. The power supply control means according to claim 1, wherein the transmission of the digital information from the conversion means to the intermittent operation control means is set so as to be performed in synchronization with the switching frequency of the power supply transformer means. . 3. The conversion means is provided with a plurality of mutually switchable channels, an arbitrary channel among all the channels is connected to the temperature detector, and the remaining channels are connected to the power transformer means. 3. The apparatus according to claim 1, wherein input of analog information to a channel connected to the temperature detector and input of analog information to a channel connected to the power transformer are performed alternately. Energization control means described in 1. 4. An intermittent operation control means for controlling an intermittent operation of energization from a commercial power supply to a heating element by the intermittent means in accordance with digital information output from the conversion means to adjust a heat generation temperature of the heating element. An energization control unit according to any one of claims 1 to 3. 5. A fixing device for heating a recording medium by heating means while passing a sheet-shaped recording medium carrying an unfixed image between a fixing body and a pressing body pressed against each other, The heating means is provided with a temperature detector, and the heating means is provided with a heating element which generates heat when supplied with electricity from a commercial power supply, and the heating element is controlled to be supplied with electricity from the commercial power supply by the electricity supply control means of claim 1. A fixing device, comprising: 6. The fixing device according to claim 5, wherein the transmission of the digital information from the conversion means to the intermittent operation control means is set so as to be performed in synchronization with the switching frequency of the power transformer means. 7. The converting means is provided with a plurality of mutually switchable channels, an arbitrary channel among all the channels is connected to the temperature detector, and the remaining channels are connected to the power transformer means. The input of analog information to a channel connected to the temperature detector and the input of analog information to a channel connected to the power transformer are alternately performed. 3. The fixing device according to claim 1. 8. The intermittent operation control means controls the intermittent operation of energization from the commercial power supply to the heating element by the intermittent means in accordance with the digital information output from the conversion means to adjust the heat generation temperature of the heating element. The fixing device according to any one of claims 5 to 7, wherein 9. An image forming apparatus for forming an image in accordance with image information from the outside on a sheet-shaped recording medium, wherein the power supply control means according to claim 1 and the fixing device according to claim 5. An image forming apparatus comprising: 10. The image forming apparatus according to claim 9, wherein the transmission of the digital information from the conversion means to the intermittent operation control means is set so as to be performed in synchronization with the switching frequency of the power transformer means. . 11. The converting means is provided with a plurality of mutually switchable channels, an arbitrary channel among all channels is connected to a temperature detector, and the remaining channels are connected to power transformer means. 11. The apparatus according to claim 9, wherein input of analog information to a channel connected to the temperature detector and input of analog information to a channel connected to the power transformer are performed alternately. An image forming apparatus according to claim 1. 12. The intermittent operation control means controls intermittent operation of energization from a commercial power supply to the heating element by the intermittent means in accordance with digital information output from the conversion means to adjust the heat generation temperature of the heating element. The image forming apparatus according to any one of claims 9 to 11, wherein: