JP2002156849A - Image forming device and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform control with the most suitable current consumption and a high productivity without flow of an excessive AC current with respect to an image forming device 601 provided with an image fixing part having an electromagnetic induction heating device A as an image heating means. SOLUTION: The image forming device is provided with a current control means which controls the supply current to the electromagnetic induction heating device A and a control means 526 which controls a current supply means, loads required for image formation, and the entire device to control the image forming operation, and the control means which controls the entire device to perform the image forming operation at the time of image formation has an operation means which calculates the supply current to the electromagnetic induction heating device in accordance with the control state of each load required for image formation on the basis of a preliminarily set maximum available current set value, and a current control means which controls the current in accordance with the calculation result is provided to limit the current for use in the entire device within the maximum available current set value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus provided with an image fixing section using an electromagnetic induction heating device as an image heating means.
And a control method of the image forming apparatus.

[0002]

2. Description of the Related Art For the sake of convenience, a heat fixing device (fixer) as a heating device which is provided in an image forming apparatus such as an electrophotographic copying machine or a printer and heat-fixes an unfixed image formed and carried on a recording medium is provided. An example will be described.

A thermal fixing device of an image forming apparatus uses a suitable image forming means such as an electrophotographic process, an electrostatic recording process, a magnetic recording process or the like to record a recording medium (transfer material sheet, electrostatic recording paper, electrofax paper, printing, etc.). A non-fixed image (toner image) corresponding to target image information formed and carried on a transfer method or a direct method on paper or the like) is thermally fixed as a permanent image on a recording medium surface. Generally, a halogen heater is used as a heat source. The heat roller type heat fixing device described above is often used.

[0004] This heat roller type heat fixing device basically has a parallel pressure contact roller pair of a fixing roller, which is a heating roller (heat roller), and a pressure roller, and rotates the roller pair to press the roller pair. The recording medium to be subjected to the image fixing process is introduced into the heating nip, which is nipped and conveyed, and the unfixed image is heated and melted by the heat of the fixing roller and the pressing force of the pressure contact portion so as to penetrate into the recording medium surface. It is to fix it.

The fixing roller generally has a hollow metal roller of aluminum as a base and has a heat-resistant rubber layer or the like as a release layer (offset preventing layer) formed on the outer peripheral surface thereof. The halogen heater is inserted and arranged. The halogen heater is in the form of an elongated rod sealed with glass.

The pressure roller is composed of a core metal and a heat-resistant elastic layer of silicone rubber or the like formed concentrically around the core metal. A heating nip having a predetermined width is formed between the pressure roller and the fixing roller by elastic deformation of the elastic layer. Is formed.

[0007] The halogen heater of the fixing roller generates heat by applying electric power, and the heat is transmitted to the hollow metal roller base of the fixing roller by the blowing and convection, thereby heating the metal roller base. The metal roller base has a function of uniformly transmitting the received heat to the entire roller, and the fixing roller has a uniform temperature distribution.

The halogen heater is connected to an AC power supply (line input power supply) via a switching control element such as a triac, and power is supplied from the AC power supply.

A temperature detecting element, generally a thermistor heat-sensitive element, is externally connected to the fixing roller. The temperature of the fixing roller is detected by the heat-sensitive element, and power supply to the halogen heater is turned on / off by a switching element based on the detected temperature information. Under the control, the temperature of the fixing roller is controlled to a target constant temperature.

However, in the heat fixing apparatus using the halogen heater as described above, the rod-shaped halogen heater as a heat source is disposed at the center of the hollow portion of the roller, which is far away from the roller substrate to which heat is to be transmitted, and thus reaches the roller. Due to the thermal resistance and the heat capacity of the roller, the thermal model has a very complicated configuration and is difficult to analyze.

On the other hand, as a heat fixing device having a simple heat transfer model from a heat source, there is a heating device of an electromagnetic induction heating system.

In this method, a magnetic field is applied from a magnetic field generating means to an electromagnetic induction heating member to generate an eddy current, thereby generating heat by Joule heat and heating the image on a recording medium by the heat generation. The electromagnetic induction heating member may be in the form of a rotating metal roller, a fixed metal plate, a rotating or moving metal film, or the like.

An exciting coil is used as the magnetic field generating means. The excitation coil is connected to an AC input via a switching element (MOSFET, transistor, IGBT, etc.) and a rectifier, together with a resonance capacitor for performing a resonance operation. When the switching element is turned on, electric power is supplied to the exciting coil, and the high frequency magnetic field generated by the exciting coil causes the electromagnetic induction heating member as the heating member to generate heat.

The temperature control of the thermal fixing device of the electromagnetic induction heating type, more specifically, the temperature control of the electromagnetic induction heating member as a heating member, is performed by a temperature detecting element arranged close to or in contact with the electromagnetic induction heating member. The temperature of the electromagnetic induction heating member is detected by a thermistor temperature sensing element, the detected temperature information is compared with a predetermined temperature by a control circuit, and the on time of the switching element is controlled in accordance with the comparison result. The induction heating member is controlled so as to obtain a target constant temperature.

[0015] Such a heat fixing device of the electromagnetic induction heating type has a very simple heat transfer model from a heat source and high thermal efficiency as compared with a heating device of a heat roller type, and has an electromagnetic induction heating member or a heating member as a heating member. The part can be quickly and efficiently started up from room temperature to a predetermined high temperature, the time required to reach the predetermined temperature is short, and quick start (shortening of wait time) is possible. It is possible to configure a device capable of saving power without having to perform standby temperature control in the standby state.

[0016]

However, when an image is formed in an image forming apparatus provided with an image fixing unit using the above-described electromagnetic induction heating device as an image heating means, the current supplied to the electromagnetic induction heating device is maximized. While outputting with efficiency
By operating the load necessary for image formation, the power supply A
If the C current value flows excessively, the power may be excessively consumed and may exceed the current value that can be consumed by the power supply means.

In the case of performing an image forming operation, in order to limit the maximum amount of current, it is preferable to avoid a power supply current peak at the time of starting a load in which current consumption becomes large, so that an electromagnetic induction heating device as a heat fixing device is used. However, in this case, the power supply to the electromagnetic induction heating device is delayed by the time to avoid the peak of the power supply current, so that the image formation start time is delayed, and the productivity is reduced. However, there is a problem that is reduced.

An object of the present invention is to solve the above-mentioned problems in an image forming apparatus provided with an image fixing section using an electromagnetic induction heating device as an image heating means. An object of the present invention is to prevent an excessive AC current from flowing. Another object of the present invention is to provide an image forming apparatus capable of realizing high-productivity control with optimum current consumption.

[0019]

According to the present invention, there is provided an image forming apparatus having the following structure, and a method of controlling the image forming apparatus.

(1) An image forming apparatus having an image fixing section using an electromagnetic induction heating device for heating a fixing member for heating an image on a recording medium by electromagnetic induction heating as an image heating means, 1) the electromagnetic induction heating device Current control means for controlling the current supplied to the apparatus; 2) current control means for the electromagnetic induction heating device; and control means for controlling an image forming operation by controlling a load required for image formation; and 3) an image. Storage means for storing the amount of current flowing according to the state of the load required for forming; 4) storage means for storing the maximum usable current amount in the image forming apparatus; 5) controlling the image forming operation during image formation Controlling means for supplying to the electromagnetic induction heating device the amount of current flowing according to the stored control state of the load necessary for image formation and the maximum usable current amount. A calculation means for calculating a possible amount of current, 6) based on the calculation result of the calculating means, the image forming apparatus characterized by having a control unit for controlling the amount of current supplied to the electromagnetic induction heating device.

(2) The image forming apparatus according to claim 1, wherein the maximum usable current amount stored in the storage means is a maximum usable current amount corresponding to a power supply voltage.

(3) In an image forming apparatus having an image fixing section in which an electromagnetic induction heating device for heating an image on a recording medium by electromagnetic induction heating is used as an image heating means, when an image is formed, the control means is used. From the stored maximum amount of current that can be used in the image forming apparatus and the amount of current flowing according to the control state of the load required for image formation, the amount of current that can be supplied to the electromagnetic induction heating device is calculated by the control unit. Controlling the amount of current supplied to the electromagnetic induction heating device based on the calculation result.

<Operation> That is, the image forming apparatus of the present invention controls the current consumption of the entire image forming apparatus at the time of image formation so as to prevent a current exceeding a predetermined value from flowing through the AC line. Current control means for controlling the supply current to the electromagnetic induction heating device, the current supply means,
And a load required for image formation, and control means for controlling the image forming operation by controlling the entire apparatus, and at the time of image formation, a control means for controlling the entire apparatus to perform the image forming operation, Based on a preset maximum available current set value, in accordance with the control state of each load required for image formation, has a calculating means for calculating the supply current to the electromagnetic induction heating device, according to the calculation result The apparatus has current control means for performing current control, and limits the current used in the entire apparatus to the maximum usable current set value.

As described above, the image forming apparatus of the present invention has the current control means for controlling the current supplied to the electromagnetic induction heating device according to the load output at the time of image formation, so that the current used in the entire apparatus can be reduced. By providing the control means for limiting the current to the maximum usable current set value, it is possible to provide an image forming apparatus which can be controlled with an optimum current consumption without a predetermined current or more flowing through the power supply AC line.

The current supply to the electromagnetic induction heating device is as follows:
In particular, there is no need to turn on the power supply current at the start of the load when the current consumption becomes large, so that it is not necessary to turn on the power supply. Can be provided.

[0026]

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

Embodiment 1 (1) Example of Image Forming Apparatus (FIG. 1) FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus. The image forming apparatus of this example is a laser printer 501 using a transfer type electrophotographic process.

Reference numeral 517 denotes a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) as an image carrier, which is rotationally driven at a predetermined peripheral speed (process speed) clockwise as indicated by an arrow a. .

The photosensitive drum 517 is uniformly charged to a predetermined polarity and potential by the primary charging roller 519 during the rotation process. Scanning of the uniformly charged surface of the rotating photosensitive drum 517 by a laser beam modulated (ON / OFF controlled) corresponding to a time-series electric digital pixel signal of target image information output from the laser scanner unit 507. Exposure L is performed, and an electrostatic latent image of target image information is formed on the surface of the rotating photosensitive drum 517.

The formed latent image is developed by a developing device 520 with toner and visualized. As a development method, a jumping development method, a two-component development method, an FEED development method, or the like is used, and a combination of image exposure and reversal development is often used.

On the other hand, a recording medium (recording material, hereinafter referred to as a transfer material) S accommodated in the paper feeding cassette 502 is fed out one by one by the driving of the paper feeding roller 505, and the photosensitive drum 517 is brought into contact with the photosensitive drum 517 by the registration roller pair 506. Transfer charging roller 521
Is fed at a predetermined control timing to a transfer nip portion which is a pressure contact portion of the photosensitive drum 517 on the surface of the fed transfer material S.
The toner image on the surface side is sequentially transferred.

The transfer material S coming out of the transfer nip portion is sequentially separated from the surface of the rotary photosensitive drum 517, and is introduced into a heat fixing device A which is an electromagnetic induction heating device for fixing the toner image. It undergoes heat fixing processing. The heat fixing device A will be described in detail in the following section (2).

The transfer material S that has exited the heat fixing device A is printed out on a stacking tray 512 by a discharge roller 511.

The rotating photosensitive drum surface after the transfer material is separated is cleaned by a cleaning device 522 to remove adhering contaminants such as untransferred toner, and is repeatedly provided for image formation.

The printer 501 of the present embodiment includes the photosensitive drum 51
7. The four process devices of the primary charging roller 519, the developing device 520, and the cleaning device 522 are collectively provided as a process cartridge (image forming unit) 508 that is detachable from the printer main body.

In the laser scanner unit 507, 513
Denotes a laser unit, and an image signal (image signal VD) transmitted from an external device 531 such as a personal computer.
The laser light modulated based on O) is emitted. 514
Represents the laser light from the laser unit 513
Reference numeral 514a denotes a polygon mirror for scanning the mirror 17, reference numeral 514a denotes a motor for rotating the mirror, reference numeral 515 denotes an imaging lens group, and reference numeral 516 denotes a folding mirror.

Reference numeral 503 denotes a cassette paper presence / absence sensor for detecting the presence / absence of a transfer material S as a recording medium in the cassette 502;
Reference numeral 504 denotes a cassette size sensor (consisting of a plurality of micro switches) for detecting the size of the transfer material S of the cassette 502, and reference numeral 510 denotes a paper discharge sensor for detecting the transfer material conveyance state of the paper discharge unit. Reference numeral 529 denotes a heat exhaust fan.

Reference numeral 523 denotes a main motor which applies a driving force to the feed roller 505 via a feed roller clutch 524 and a driving force to the pair of registration rollers 506 via a registration clutch 525. A driving force is also applied to each unit of the process cartridge 508 including the heat fixing device A, the discharge roller 511, and the like.

Reference numeral 526 denotes an engine controller, which includes a laser scanner unit 507, a process cartridge 508,
The control of the electrophotographic process by the heat fixing device A, the conveyance control of the transfer material S in the printer main body 501, and the like are performed.

Reference numeral 527 denotes a video controller, which is connected to an external device 531 such as a personal computer by a general-purpose interface (Centronics, RS232C, etc.) 530, and develops image information sent from the general-purpose interface into bit data. The bit data is transmitted as a VDO signal to the engine controller 526 via the interface 528.

FIG. 2 shows a power supply configuration of the present image forming apparatus. The power supply to the image forming apparatus 501 includes a power supply circuit 100 for supplying power to the thermal fixing device A and a low-voltage power supply unit 101 for supplying low-voltage power to devices other than the thermal fixing device A. The AC cord 102 connected to the unit 101 shares one cord.

(2) Thermal Fixing Device A (FIG. 3) FIG. 3 is a schematic structural view of the thermal fixing device A. The heat fixing device A of this example is a heat roller type device of an electromagnetic induction heating system.

Reference numeral 1 denotes a fixing roller as a heating roller, and 2 denotes a pressing roller. The pressing roller is arranged in parallel with each other and presses with a predetermined pressing force to form a heating nip N having a predetermined width between the rollers 1 and 2.
(Heating unit), and is driven to rotate at a predetermined peripheral speed in the direction indicated by the arrow.

The fixing roller 1 is made of Ni, Cu, Cr, F
e, a hollow roller made of a magnetic metal such as Co is used as a base 1a, and a heat-resistant rubber layer or the like is formed as a release layer 1b on the outer peripheral surface thereof.

The pressure roller 2 is composed of a core 2a and a heat-resistant elastic layer 2b of silicone rubber or the like formed concentrically around the core, and is fixed between the fixing roller 1 and the elastic layer 2b by elastic deformation. A heating nip N having a predetermined width is formed.

Reference numeral 3 denotes an exciting coil as a magnetic field generating means, which is a horizontally long member whose longitudinal direction is perpendicular to the drawing, and is inserted and disposed in the hollow of the fixing roller 1. The exciting coil 3
Is composed of a winding (wire loop) 3a for generating a magnetic flux, and a core (core material) 3b made of a ferromagnetic material having a high magnetic permeability, such as ferrite, for concentrating the magnetic flux and forming a magnetic path.

Reference numeral 4 denotes a temperature detecting element for detecting the temperature of the fixing roller 1, for example, a thermistor. In this example, the fixing roller 1 is used.
And is disposed close to or in contact with a position corresponding to the transfer material loading side near the heating nip N.

The above-described assembly 10 of the magnetic metal-made fixing roller 1, the exciting coil 3, and the temperature detecting element 4 is an electromagnetic induction heating means (fixing unit). Hereinafter, it is referred to as a fixing roller unit. Reference numerals 11, 12, and 13 denote connectors for electrically connecting the exciting coil 3 and the temperature detecting element 4 of the fixing roller unit 10 to the power supply circuit 100.

The excitation coil 3 is connected to the winding 3a by a power supply circuit 100.
A high-frequency magnetic field is generated when a high-frequency current flows from the device. Fixing roller 1 whose base 1a is made of magnetic metal
Since the main magnetic path is formed with the core 3b of the exciting coil 3 in the heating nip N, most of the magnetic flux generated from the exciting coil 3 is mainly supplied to the fixing roller portion in the heating nip N portion. When a high-frequency magnetic field is applied to the magnetic metal, eddy current loss occurs, and the fixing roller 1 itself generates electromagnetically induced heat.

The temperature of the fixing roller 1 is detected by a temperature detecting element 4, and the detected temperature information is input to a power supply circuit 100 and compared with a preset temperature. Under the control, the temperature of the apparatus, that is, the temperature of the fixing roller 1 or the temperature of the heating nip N is controlled to a target constant temperature.

When the fixing roller 1 and the pressure roller 2 are rotated, and the fixing roller 1 is heated to a predetermined temperature by electromagnetic induction heating, a heating nip serving as a pressure contact portion between the roller pair 1 and 2 is formed. The transfer material S to be image-fixed is introduced into N and is conveyed by being pinched and conveyed, and the unfixed image (toner image) T is heated and melted by the heat of the fixing roller 1 and the pressing force of the press-contact portion so as to permeate the transfer material surface. And heat fixation.

(3) Feeding Circuit 100 (FIG. 4) FIG. 4 is a circuit diagram of the feeding circuit 100. The power supply circuit 100 is roughly divided into a. A high-frequency current generating circuit 10 as excitation coil driving means for turning on / off the power supply to the excitation coil in order to generate a high-frequency magnetic field in the excitation coil 3
0A, b. An electromagnetic induction control circuit 100B is provided as control means for variably controlling the ON time or the OFF time of the power supply to the exciting coil 3 of the exciting coil driving means, or the ON time and the OFF time.

In the high-frequency current generating circuit 100A as the exciting coil driving means, the AC input 15
Is rectified by the diode bridge 16 and smoothed by the capacitor 17. Reference numeral 18 denotes a resonance capacitor for performing a resonance operation with the exciting coil 3, and a rectified AC
The input 15 is connected to the switching element 19 (MOSFET, transistor, IGBT, etc.) and the overcurrent detection resistor 20 via the exciting coil 3 and the resonance capacitor 18.
The rectified AC input 15 is turned on / off by a switching element 19, and a high-frequency current is supplied to the exciting coil 3. The exciting coil 3 generates a high-frequency magnetic field, causing eddy current loss in the metal part of the fixing roller 1 as described above, and the fixing roller 1 generates electromagnetic induction heat.

An electromagnetic induction control circuit 100B as on-time or off-time control means controls the switching element 19 of the high-frequency current generating circuit 100A so as to keep the device temperature detected by the thermistor 4 at a target temperature.
The detection voltage of the thermistor 4 is obtained by adding the reference voltage Vref to the resistor 26.
And the result of voltage division by the thermistor 4, and this detected voltage is compared and amplified by the error amplifier 22 with the target voltage 23 (target temperature). The error amplifier 22 plays a role of amplifying an error between the target voltage and the detected voltage. Error amplifier 2
The output of No. 2 is input to the control unit 21, and a PWM waveform suitable for the temperature condition is output. This output is output from the AND circuit 24.
Is compared with the output from the current limiter 27,
The switching element 19 is driven via the resistor 25.

The control section 21 is a part of the engine controller 526 in FIG. 1. In the fixing temperature adjustment control, the output of the error amplifier 22 is input, and the temperature condition is controlled in accordance with the output data of the error amplifier 22. Suitable P
Outputs WM waveform.

(4) Image Forming Operation Next, the image forming control in the above configuration will be described.

I) First, control other than the heat fixing device A of the electromagnetic induction heating system will be described.

Engine controller 526 in FIG.
Receives the image forming instruction, first receives the main motor 523
And loads other than the laser scanner unit 507 are activated.

At this time, the timer 1 is set to operate for a time tl, which is a time required for the current other than the main motor 523 and the laser scanner unit 507 to reach a stable current after passing the peak value of the amount of current required for starting the load.

Further, when the operation start timing of the laser scanner section 507 has been reached, the laser scanner section 50
7 is started.

Further, the timer 2 is set to operate for a time t2, which is a time required for the laser scanner unit 507 to reach a stable current after passing the peak value of the amount of current required for starting the laser scanner unit 507.

Further, when the operation start timing of the main motor 523 is reached, the activation of the main motor 523 is started.

Further, the timer 3 is set to operate for a time t3, which is a time required for the main motor 523 to reach a stable current after the peak value of the current amount required for starting the main motor 523 has elapsed.

Ii) Next, the control of the heat fixing device A of the electromagnetic induction heating type will be described.

The engine controller 526 starts the loads other than the main motor 523 and the laser scanner unit 507 in response to the image forming instruction as described above, and at the same time, starts the control of the heat fixing device A.

At this time, the current supply to the heat fixing device A is performed by the main motor 5 set in advance from the total consumed AC current.
Control is performed based on a control value based on the amount of current obtained by subtracting the amount of current consumed at the time of starting a load other than 23 and the laser scanner unit 507.

The control performed by the engine controller 526 after the control of the heat fixing device A is started will be described with reference to the flowchart of FIG.

Here, the maximum current limit value to be limited when supplying power in the fixing temperature control is held as data. At the start of the control, first, the maximum current limit is initialized to the maximum value that can be supplied during the stored image forming operation (step: S201).

Next, it is determined whether or not the timer 1 set when starting loads other than the main motor 523 and the laser scanner unit 507 is operating (step: S20).
2).

When the timer 1 is operating, the stored main motor 523 is stored based on the maximum current limit amount.
Then, a value obtained by subtracting the amount of current required at the time of startup by loads other than the laser scanner unit 507 is set again as the maximum current limit amount (step: S203).

If the timer 1 is not operating, the process proceeds to the next step: S204.

Next, it is determined whether or not the timer 2 set when activating the laser scanner unit 507 is being activated (step: S204).

When the timer 2 is operating, the stored laser scanner unit 507 is used based on the maximum current limit.
Sets the value obtained by subtracting the amount of current required at startup as the maximum current limit amount again (step: S205).

If the timer 2 is not operating, the process proceeds to the next step: S206.

Next, it is determined whether or not the timer 3 set when starting the main motor 523 is operating (step: S206).

When the timer 3 is operating, a value obtained by subtracting the stored current amount required for starting the main motor 523 from the maximum current limit amount is set again as the maximum current limit amount (step S3). : S207).

If the timer 3 is not operating, the process proceeds to the next step: S208.

Through the above steps, the PWM output is determined and controlled based on the finally set maximum current limiting amount and the measured temperature value from the electromagnetic induction heating fixing device A (step: S208).

During the image forming operation, the control routine of the heat fixing device A includes steps S201 to S2.
By repeating the steps up to 08, the temperature is controlled by the optimum control current amount.

FIG. 6 illustrates the above control.
In FIG. 6, the main motor 5 starts from the start of the image forming operation.
23, the state of current supply to the thermal fixing device A according to the respective activation states of the laser scanner unit 507 and other loads are shown along time lines.

As described above, according to this control, the amount of AC current in the entire apparatus during the image forming operation is controlled to be constant, so that a predetermined amount of current does not flow through the power supply AC line. An image forming apparatus controlled with optimal power consumption can be provided.

The current is supplied to the electromagnetic induction heating device, which is a heat fixing device, immediately after the start of the image forming operation. It is possible to provide an image forming apparatus that can avoid the reduction.

Here, as a measure corresponding to the configuration described in the claims, the “power supply circuit 100” is “current control means for controlling the current supplied to the electromagnetic induction heating device”. The “engine controller 526” is “a current control unit of the electromagnetic induction heating device and a control unit that controls an image forming operation by controlling a load necessary for image formation”. In addition, the memory circuit, the arithmetic circuit, and the control circuit (control unit 21) included in the engine controller 526 include “storage means for storing an amount of current flowing according to the state of a load necessary for image formation”, “ Storage means for storing the maximum usable current amount "," calculation means ", and" control means for controlling the amount of current supplied to the electromagnetic induction heating device based on the calculation result of the calculation means ".

<Embodiment 2> In this embodiment, the type determining means of the fixing roller unit 10 in the image forming apparatus of Embodiment 1 is added. This will be described with reference to FIG.

The thermal fixing device A of this embodiment has a fixing roller 1 including an exciting coil 3 and a temperature detecting element 4, that is, a fixing roller unit 1 in which an electromagnetic induction heating means can be detachably attached to and removed from the apparatus.
It is configured as 0. The pressure roller 2 and the power supply circuit (control power supply unit) 100 for the fixing roller 1
Alternatively, it is provided on the image forming apparatus main body side provided with the heat fixing device A side.

By fixing the fixing roller unit 10 to the apparatus in a predetermined manner, the fixing roller 1 is brought into pressure contact with the pressure roller 2 on the apparatus side in a predetermined manner, and a predetermined heating nip N is provided therebetween.
Is formed, and the winding 3a of the exciting coil 3
And temperature detecting element 4 are connected to connectors 11, 12, and 13, respectively.
Through the power supply circuit 100 on the device side.

The fixing roller unit 10 has a plurality of types 1 such as 100 V type and 200 V type depending on the commercial power supply voltage.
0A and 10B are prepared, and each of these types of fixing roller units 10A and 10B can be attached to and detached from the apparatus.

In this embodiment, the type of the fixing roller unit 10 mounted on the apparatus is determined electrically by a discriminating operation, and the power supply circuit 10 on the apparatus side is determined in accordance with the discrimination type.
0 functions properly in accordance with the type of the fixing roller unit 10 (A / B) to which the fixing roller unit 10 is attached.

The type determining means of the fixing roller unit 10 can be variously constructed. FIG. 7 shows an example, in which 10A is a fixing roller unit for a 100V system and 10B is a fixing roller unit for 200V.
40a and 40a are the respective fixing roller units 10A and 1
0B, and a pair of corresponding electrical contacts 40b provided on a power supply circuit 100 side of the apparatus when the fixing roller unit 10A or 10B is mounted to the apparatus in a predetermined manner. Be in electrical contact. The pair of electrical contacts 40a, 40a on the fixing roller units 10A, 10B side and the pair of corresponding electrical contacts 40b, 40b on the device side constitute a type discriminating switch 40 of the fixing roller unit mounted on the device.

Then, for the fixing roller unit 10A for the 100V system, the pair of electric contacts 40a
The two are electrically connected to each other by a jumper wire 60. on the other hand,
In the 200V-system fixing roller unit 10B, no jumper wire is provided, and the pair of electric contacts 40a are electrically disconnected.

Therefore, when the fixing roller unit 10A for the 100V system is mounted on the apparatus, the discrimination switch 40 is turned on due to the presence of the jumper line 60. On the other hand, when the fixing roller unit 10B for the 200V system is mounted on the apparatus, the discriminating switch 40 is turned off because there is no jumper wire 60. This discriminating switch 4
Whether the fixing roller unit mounted by turning on / off 0 is for 100 V system or 200 V system is electrically determined on the power supply circuit 100 side of the apparatus.

In the apparatus having the above-described configuration, in FIG.
The maximum current limit determining means in the flowchart shown in FIG. 8 will be described with reference to the flowchart of FIG. Whether the fixing roller unit is for a 100V system,
It is determined whether it is for the V system (step: S30
1) Set the initial value of the current limit amount for the 200 V system stored in the control unit 21 for the 200 V system (step: S302), and store the stored current limit value for the 100 V system for the 100 V system. The current limit amount initial value is set (step: S303). Thereby, it is most suitable for the fixing roller unit according to the power supply voltage, and also in the entire image forming apparatus,
It is possible to provide an image forming apparatus that is controlled with optimal current consumption.

[0093]

As described above, according to the present invention, by providing current control means for controlling the current supplied to the electromagnetic induction heating device in accordance with the load output during image formation, the entire device can be controlled. By providing control means for limiting the current used to within the maximum usable current setting value, it is possible to provide an image forming apparatus which is controlled at an optimum current consumption without a current exceeding a predetermined value flowing through the power supply AC line. It becomes possible.

The current supply to the electromagnetic induction heating device is as follows:
In particular, there is no need to turn on the power supply current at the start of the load when the current consumption becomes large, so that it is not necessary to turn on the power supply. Can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment.

FIG. 2 is a configuration diagram of a power supply unit of the image forming apparatus.

FIG. 3 is a schematic configuration diagram of a heat fixing device (electromagnetic induction heating device).

FIG. 4 is a configuration diagram of a power supply circuit.

FIG. 5 is a control flowchart.

FIG. 6 is an example of a control timing chart.

FIG. 7 is an explanatory diagram of a type determination unit of a fixing roller unit according to the second embodiment.

FIG. 8 is an operation flowchart of a maximum current limiting amount determining unit.

[Explanation of symbols]

A ·······················································
.Pressing roller, 3... Excitation coil, 3a... Winding, 3b
..Cores, 4 ° temperature detecting elements (thermistors, etc.), 10
(A ・ B) ··· Fixing roller unit, 100 ··· Power supply circuit, S ··· Transfer material, T ··· Toner image

Claims (3)

[Claims] 1. An image forming apparatus having an image fixing section using an electromagnetic induction heating device for heating a fixing member for heating an image on a recording medium by electromagnetic induction heating as an image heating means, 1) to the electromagnetic induction heating device Current control means for controlling the supply current of the electromagnetic induction heating device, and control means for controlling an image forming operation by controlling a load required for image formation; and 3) image formation. Storage means for storing the amount of current flowing according to the state of the load necessary for the image forming apparatus; 4) storage means for storing the maximum usable current amount in the image forming apparatus; and 5) controlling the image forming operation during image formation. The control means can supply the current to the electromagnetic induction heating device based on the amount of current flowing according to the stored control state of the load necessary for image formation and the maximum usable current amount. A calculating means for calculating a flow rate, 6) based on the calculation result of the calculating means, the image forming apparatus characterized by having a control unit for controlling the amount of current supplied to the electromagnetic induction heating device. 2. The image forming apparatus according to claim 1, wherein the maximum usable current amount stored in said storage means is a maximum usable current amount corresponding to a power supply voltage. 3. An image forming apparatus having an image fixing unit using an electromagnetic induction heating device for heating a fixing member for heating an image on a recording medium by electromagnetic induction heating as an image heating unit, wherein the image is stored in a control unit when an image is formed. From the maximum amount of current that can be used in the image forming apparatus and the amount of current flowing according to the control state of the load required for image formation, the amount of current that can be supplied to the electromagnetic induction heating device is calculated by the control unit. Controlling the amount of current supplied to the electromagnetic induction heating device based on the calculation result.