JP2001331057A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of speedily returning a mode from an energy-saving mode to a normal mode while minimizing an adverse effect due to a flicker phenomenon. SOLUTION: The image forming device, in which the mode is shifted from the normal mode to the energy-saving mode in order to reduce power consumption in a standby state, is provided with a fixing control means 1e of a first system and a fixing control means 1f of a second system to control the temperature of a fixing device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a laser printer, a facsimile, and the like, which can shift from a normal mode to an energy saving mode in order to reduce power consumption in a standby state.

[0002]

2. Description of the Related Art In recent image forming apparatuses, there is a strong demand for energy saving. In particular, it is required to reduce power consumption during standby. In order to satisfy this demand, many image forming apparatuses are provided with an energy saving mode in which a part of power supply to a fixing device for thermally fixing a transferred image during standby or an unnecessary power supply to a control unit is stopped. . On the other hand, especially in the European region, it is required to reduce the return time from the energy-saving mode to the normal mode, and how to quickly shift from the energy-saving mode to the normal mode in which the image forming apparatus can operate, and a control unit that has been stopped. It is an important issue to determine the specifications of the energy saving mode how quickly it is started. Further, the energy saving mode in the image forming apparatus can be expected to greatly reduce the power consumption during standby with respect to the fixing apparatus which supplies a large amount of power, and is adopted in many image forming apparatuses. However, when a commercial power supply is connected to a heating wire heater such as a halogen heater to supply a heat source to the fixing device, a large amount of inrush power is required at the start of the power supply to the halogen heater. And the circuit element is destroyed by the generation of the back electromotive voltage. Therefore, Japanese Patent Application Laid-Open
In JP-A-224559 and JP-A-10-74023, phase control is performed in which the power is turned on or off at a zero-cross point of a commercial power supply and the phase angle at the time of energization is changed for control.

[0003]

However, in order to perform the above-described phase control, it is necessary to first confirm the frequency of the commercial power supply and control the lighting of the heater at an optimal phase angle corresponding to the frequency. is there. Therefore, when performing phase control, it is necessary to measure the frequency of the commercial power supply before starting the lighting control of the heater, so that the start of the lighting control of the heater is delayed by the time required for the measurement, and the fixing device is started up. There is a problem that it takes time until. Further, if on / off control is performed by changing the time of turning on / off the power used for the heat source without using the phase control, the frequency of the commercial power as described above can be set before starting the lighting control of the heater. Although it is not necessary to perform the measurement, a flicker phenomenon and a back electromotive voltage occur, which causes voltage fluctuation and high frequency noise. Therefore, the problem to be solved by the present invention is to reduce the adverse effect of the flicker phenomenon by taking advantage of both the on / off control and the phase control, and to quickly return from the energy saving mode to the normal mode. An object of the present invention is to provide a forming apparatus.

[0004]

In order to solve the above-mentioned problems, in the image forming apparatus according to the first aspect, it is possible to shift from a normal mode to an energy saving mode in order to reduce power consumption in a standby state. Image forming apparatus,
It is characterized by comprising a first type of fixing control means for controlling the temperature of the fixing device and a second type of fixing control means. According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the first type of fixing control unit performs on / off control for changing and controlling a power supply on / off time. The two-type fixing control means is characterized in that it is turned on or off at the time of a zero crossing of the frequency of the power supply, and performs phase control in which the phase angle at the time of energization is changed and controlled. According to a third aspect of the invention, in the image forming apparatus according to the second aspect, the temperature control by the first type fixing control unit is performed when the power of the image forming apparatus is turned on, and the temperature control by the second type fixing control unit. Is performed at the time of returning from the energy saving mode to the normal mode. In the invention according to claim 4,
3. The image forming apparatus according to claim 2, wherein the temperature control is performed by selecting the first type of fixing control unit or the second type of fixing control unit based on the temperature of the fixing device when returning from the energy saving mode to the normal mode. It is characterized by. Further, in the image forming apparatus according to the fifth aspect, in the image forming apparatus according to the fourth aspect, when the temperature of the fixing device at the time of returning from the energy saving mode to the normal mode is lower than a predetermined temperature, the first is performed. When the temperature is higher than a predetermined temperature, a second type of fixing control means is selected and the temperature is controlled. In the image forming apparatus according to the sixth aspect, in the image forming apparatus according to the third, fourth or fifth aspect, when returning from the energy saving mode to the normal mode, the sequence control necessary for the return is prioritized, This is characterized in that the sequence control is executed in order from the highest priority.

[0005]

According to the first aspect of the present invention, there is provided a first type fixing control unit or a second type fixing control unit having different characteristics when controlling the temperature of a fixing device. The temperature of the fixing device can be controlled by selecting one of the two. According to a second aspect of the present invention, in addition to the invention of the image forming apparatus configured as in the first aspect, the rise of the temperature of the fixing device is accelerated by on / off control of the first type fixing control means. The flicker phenomenon can be suppressed by the phase control of the two types of fixing control means. According to a third aspect of the present invention, in addition to the invention of the image forming apparatus configured as in the second aspect, when the power of the image forming apparatus is turned on, the temperature of the fixing apparatus is controlled by the temperature control by the first type of fixing control means. At the time of returning from the energy saving mode to the normal mode, the flicker phenomenon can be suppressed by the temperature control by the fixing control means of the second system, and the function of the apparatus can be stabilized. According to a fourth aspect of the present invention, in addition to the image forming apparatus of the second aspect, the first type of fixing control means or the first type of fixing control means depends on the temperature of the fixing device when returning from the energy saving mode to the normal mode. Since the second type of fixing control means is selected to control the temperature,
The effect of shortening the return time from the energy saving mode to the normal mode and suppressing the flicker phenomenon can be adapted to the situation of the device. According to a fifth aspect of the present invention, in addition to the image forming apparatus of the fourth aspect, when returning from the energy saving mode to the normal mode,
When the temperature of the fixing device is lower than a predetermined temperature, the recovery time is shortened by executing the first type of fixing control means, and when the temperature of the fixing device is higher than the predetermined temperature, the second method is used. By executing the fixing control means, the flicker phenomenon can be improved, and in both cases, the rise time of the temperature of the fixing device can be satisfied. According to a sixth aspect of the present invention, in addition to the invention of the image forming apparatus configured as the third, fourth or fifth aspect,
When returning from the energy saving mode to the normal mode, the sequence control is executed in order from the one with the highest priority, so that the fixing device can be started up early and the return time from the energy saving mode to the normal mode can be shortened. Can be.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram showing a schematic configuration of a typical digital copying apparatus as an image forming apparatus. The digital copying apparatus is roughly composed of a scanner unit 10 and a printer unit 20. First, the scanner unit 10 will be described. The original placed on the contact glass 11 of the scanner unit 10 is the first scanning body 1
2 is illuminated by the light source 12a. The reflected light from the original is also transmitted to the first mirror 12b of the first scanning body 12, the second mirror 13a and the third mirror 13b of the second scanning body 13,
The direction is bent by the fourth mirror 14 and the fifth mirror 15, the light is condensed by the lens group 16, and an image is formed on the light receiving surface of the CCD image sensor 17 which is a photoelectric conversion element. The first scanning body 12 and the second scanning body 13 move on the lower surface of the contact glass 11 in the sub-scanning direction in parallel with the contact glass 11. The second scanning body 13 is the first scanning body 1
It moves at half the speed of two. Scanning in the main scanning direction is performed by solid-state scanning of the CCD image sensor 17, and the entire original image is read by moving the above-described optical system. Further, a pressure plate 18 is provided for pressing the original so that the original image is correctly brought into contact with the contact glass 11. Next, the printer unit 20 will be described. The printer unit 20 is roughly composed of a laser writing system 21, an image reproducing system 25, and a paper feeding system 36. The laser writing system 21 includes a laser output unit 22, a laser imaging lens 23, and a mirror 24. Inside the laser output unit 22, there is provided a laser diode as a laser light source and a holgon mirror (not shown) which is rotated at a high speed by an electric motor. The laser beam output from the laser writing system 21 is applied to the photosensitive drum 26 of the image reproducing system 25. Around the photosensitive drum 26, a charging charger 27, an eraser 28, a developing unit 29,
Transfer charger 30, separation charger 31, separation claw 3
2 and a cleaning unit 33 are provided. Here, the image reproducing process in the printer unit 20 will be briefly described. The peripheral surface of the photosensitive drum 26 is uniformly charged to a high potential by the charging charger 27.
When the laser light is radiated to the periphery, the radiated portion has a lower potential. Since the laser light is turned on / off according to the black / white state of recording / reproducing, the potential distribution corresponding to the recorded image, that is, the electrostatic latent image is formed on the peripheral surface of the photosensitive drum 26 by the irradiation of the laser light. Is done. When the portion of the photosensitive drum 26 on which the electrostatic latent image was formed passed through the developing unit 29, toner adhered according to the level of the potential on the peripheral surface of the photosensitive drum 26, and the electrostatic latent image was visualized. Turns into a toner image. At a predetermined timing, a recording sheet is fed from a paper feed cassette to a portion where the toner image is formed, and is superimposed on the toner image. The superimposed toner image is transferred to recording paper by the transfer charger 30. Thereafter, the recording paper is separated from the photosensitive drum 26 by the separation charger 31 and the separation claw 32. Further, the separated recording paper is fed to a fixing device 34 by a transport belt 33.
The fixing roller 3 is transported in the direction of
After being heated by 4a, the sheet is discharged to a sheet discharge tray 35.

The digital copying apparatus shown in FIG. 1 has two paper feed systems 36. One of the paper feeding systems includes upper paper cassettes 36a and 36b and a manual paper cassette 36c. Recording paper set in the upper paper cassette 36a and the manual paper cassette 36c is fed to an upper paper roller 36d.
Is fed by The other sheet feeding system includes a lower sheet cassette 36b.
The recording paper set in b is fed by the lower feed roller 36e. Then, the recording paper fed from one of the paper feed rollers is temporarily stopped in a state of being in contact with the registration roller 37, and is sent to the photosensitive drum 26 at a timing synchronized with the progress of the recording process. The fixing device 34 includes a pressure roller 34 in addition to the fixing roller 34a.
c, a halogen lamp 34b, a temperature detecting element (not shown), and the like. The fixing roller 34a is heated by the halogen lamp 34b, and the toner on the recording paper is melted by the heat, and is fixed on the recording paper.

FIG. 2 is a diagram showing a main portion for controlling the temperature of the fixing device. There is a sequence control plate 1 as a heart part for performing temperature control. The sequence control plate 1 performs not only the temperature control of the fixing device but also a paper feed control, a scanner reading control, a sequence control of actuators, and the like. The sequence control board 1 includes a CPU 1a for executing a command and a ROM containing a program.
1b, a RAM 1c for temporarily storing various calculation results and parameter values used for sequence control, a transistor 1d forming a part of a zero-cross detection circuit of a commercial power supply,
A first fixing controller 1e, which is a fixing control unit of a system, and a second fixing controller 1f, which is a fixing control unit of a second system, are mounted. Further, a heater control element 3 such as a triac or a thyristor for controlling the current to the halogen lamp 34b is connected to the first fixing control unit 1e and the second fixing control unit 1f of the sequence control plate 1, and is adapted to either control method. And a current based on the current. The zero-cross detection circuit includes the above-described transistor 1d and a photocoupler 4 to which commercial power is input. When the voltage value of the commercial power supply falls below a certain value, a phototransistor (not shown) built in the photocoupler 4 is turned off, and this state is transmitted to the transistor and taken into the CPU 1a.
As a result, the CPU 1a can detect the zero cross point of the commercial power supply. The temperature of the fixing roller 34a of the fixing device 34 when the current flows through the halogen lamp 34b can be detected by the temperature detecting element 5 such as a thermistor.
In addition to the sequence control board 1, exchanges data necessary for sequence control of the sequence control board 1 with a DC power supply 6 that supplies DC power to the sequence control board 1,
There is a controller board 2 for controlling communication with the outside. The controller board 2 includes a CPU 2a for executing commands and a RAM 2b for temporarily storing various calculation results and parameter values used for sequence control.

Here, from FIG. 2, FIG. 3, and FIG. 4, the first fixing control unit 1e controls on / off of the halogen lamp 34b, and the second fixing control unit 1f controls the halogen lamp 34b.
Will be described. Generally halogen lamp 3
When 4b or the like is used as a heater source of the fixing device, a lighting method often called phase control is employed in order to reduce an inrush current generated when the heater is turned on. This means that when the heater is turned on, the phase angle at which power supply to the heater is started with the zero cross point of the commercial power supply as a reference is turned on at a small phase angle at the first lighting, and gradually increased from the next cycle. The rush current generated at the time of lighting is reduced. In the image forming apparatus of this configuration, the phase angle information is recorded in the ROM 1b of the sequence control plate 1 shown in FIG. 2, and when the fixing control of the second fixing control unit 1f is performed, the CPU 1a is connected to the zero-cross detection circuit. A zero-cross point is detected from the photocoupler 4 and the transistor 1d, and transmitted to the second fixing control unit 1f. Second fixing control unit 1
f changes the phase angle at which the heater is turned on every half cycle of the commercial power supply with reference to the zero-cross point of the commercial power supply received from the CPU 1a. FIG. 4 is an example of a diagram showing a state in which it is changed every half cycle. As can be seen in FIG. 4, the first half cycle is the time T1 from the zero crossing point.
When the time elapses, the heater is turned on, and in the next half cycle, the heater is turned on when the time T2 elapses from the next zero cross point.
2, T3, T4, etc. Where π /
2>T1>T2> T3...
The times T1, T2, T3,... Are data values recorded in the ROM 1b of the sequence control board 1. However, if the frequency of the commercial power supply is different, the value of the optimum heater lighting time is also different. Therefore, it is necessary to confirm the frequency of the commercial power supply used before starting the phase control. Confirmation of this frequency is determined by detecting a zero-cross point from the photocoupler 4 and the transistor 1d, and comparing a time interval of the zero-cross point determined by the CPU 1a with a predetermined time. Further, the characteristics of this commercial power supply vary greatly depending on the power supply environment in which the image forming apparatus is used. In an environment with much noise, the photocoupler 4 may erroneously recognize the zero-cross point. The frequency of the commercial power supply is determined by measuring the time interval of the zero-cross point input in time and repeating the measurement multiple times. After determining the frequency, the CPU 1a reads a control data value of a phase angle corresponding to the frequency from the ROM 1b, and transmits the read control data value to the second fixing control unit 1f. Therefore, power supply to the sequence control board 1 is stopped at the time of shifting to the energy saving mode, and when returning from the energy saving mode to the normal mode, first, energization of the sequence control board 1 is started, and the CPU 1a is initialized. After the program starts running, the frequency is determined by repeating the time interval measurement of the zero-cross point input for a fixed time a plurality of times, and the control data value corresponding to the determined frequency is extracted from the ROM 1b of the sequence control board 1, and the second The phase control is started only by transmitting the signal to the fixing control unit 1f. Therefore, there is a problem that it takes time from the start instruction of the heater lighting to the lighting start of the halogen lamp 34b, and as a result, the start-up of the fixing device is delayed, and the return time from the energy saving mode to the normal mode is delayed.

FIG. 3 is a diagram showing the on / off control of the halogen lamp 34b by the first fixing control unit 1e. The Ton point for turning on the heater and the Toff point for turning off the heater are independent of the phase angle of the frequency. This is the time point synchronized with the ON / OFF instruction of the CPU 1a. Therefore, it is not possible to reduce the rush current generated when the heater is turned on, but there is an advantage that it is possible to perform the operation from the heater start instruction to the lighting start of the halogen lamp 34b without time delay. Therefore, the above phase control is mainly used at all times, and only when the return time from the energy saving mode to the normal mode is later than the target time,
On / off control of the halogen lamp 34b is performed by the first fixing control unit 1e, and otherwise, the second fixing control unit 1f
Is performed. FIG. 5 shows the lighting time of the heater and the temperature of the fixing device 34 (the temperature of the surface of the fixing roller 34a, but here, it is referred to as the temperature of the fixing device 34 for convenience).
FIG. Here, assuming that the target time of the temperature rise of the fixing device (time to return from the energy saving mode) is t2, the time required for frequency measurement is t1, and the operable temperature (target temperature) of the fixing device is K2. If the measurement result is K3, it takes (t2-t3) time to raise the temperature of the fixing device to the target temperature K2. Therefore, if the frequency measurement is performed first, the target start-up time (= t2) will not be enough for (t1−t3). Therefore, in this case, the CPU 1a of the sequence control plate 1 turns on the halogen lamp 34b by the first fixing control unit 1e before performing the frequency measurement first.
An instruction to perform off control is issued. First fixing control unit 1
e continues lighting until the target temperature is reached,
After the target temperature has been reached, the on / off control is started. During the continuous lighting period, the CPU 1a measures the frequency. If the temperature measurement result is K4, to raise the temperature of the fixing device to the target temperature K2, (t2-t
4) It takes time. Therefore, even if the frequency is measured first and then the phase control is performed by the second fixing control unit 1f, the target start-up time (= t2) is (t4
-T1) There is extra time. If the measurement result of the temperature is K1, the temperature of the fixing device is set to the target temperature K
It takes a time (t2−t1) to increase to 2. Therefore, in this case, the time t1 required for the frequency measurement is left. The temperature K1 is stored in the ROM 1b as reference value data.

FIG. 6 is a diagram showing a main part of the operation unit 7 of the image forming apparatus having this configuration. In the figure, only the main part will be described briefly. The start key 7a is used for a copy start festival, and reading of a document is started by pressing the key. The clear / stop key 7b is a key used to cancel input characters and numerical values, and to interrupt or stop copying or the like. The ten keys 7c are used to input the number of copies and the magnification. Hi-Fi copy key 7d
Is used when copying with better image quality. The program key 7e is a key for registering and calling frequently used setting procedures. The interrupt key 7f is used to interrupt and operate another function during copying or printing. The mode clear / preheat key 7k is a key related to the present invention. When the key is pressed for more than one second, the set contents are canceled, and when pressed for less than one second, energy saving is performed when the image forming apparatus is in the normal mode. The key is used to shift to the normal mode when the mode is switched to the energy saving mode. Further, in a general image forming apparatus, the transition from the normal mode to the energy saving mode is performed not only when the mode clear / preheat key 7k is pressed but also when the normal mode standby state continues for a predetermined time. It has become. Further, in the image forming apparatus having this configuration, the sequence control board 1
1c stores control data (timing information relating to sheet feeding, timing information relating to driving of the optical scanning system, etc.) for performing sequence control, and also stores frequency information of a commercial power supply for controlling temperature of the fixing device.
In the case where the information is loaded on the RAM 1c, the information loaded on the RAM 1c is lost each time the mode is shifted to the energy saving mode and the power supply is stopped. In order to prevent such information from being re-collected every time the mode is switched, various control data are temporarily stored in the RAM of the controller board 2 when the mode is switched from the normal mode to the energy saving mode.
2b, and the control data stored in the RAM 2b is downloaded again when returning from the energy-saving mode to the normal mode, whereby the time required for information collection can be reduced.

However, if the communication means between the sequence control board 1 and the controller board 2 is slow and the amount of control data to be downloaded is large, it takes time to download the control data, and the halogen lamp 34b which takes the longest to start up. Will be delayed. In the image forming apparatus having this configuration, the sequence control board 1 transfers the control data developed on the RAM 1c to the RAM 2b via the CPU 2a of the controller board 2 when shifting to the energy saving mode. CPU 2a of controller board 2 through serial communication line
To the energy saving mode transition completion signal. Upon receiving this signal, the CPU 2 a issues an output control signal to the DC power supply 6 and stops supplying power to the sequence control board 1. When returning from the energy saving mode to the normal mode by an external command (see the description of the mode clear / preheating key 7k in FIG. 6) or the like, the sequence control board 1 is triggered by a trigger signal from the controller board 2.
Power is started, and the sequence control board 1
After performing the initialization operation such as the above, the control data is downloaded from the RAM 2b of the controller board 2. At this time, first, information concerning the control of the halogen lamp 34b, such as the frequency measurement result of the commercial power supply necessary for starting up the fixing device, is downloaded with the highest priority, and when the control data is prepared, the halogen is prioritized over other control data acquisition. Lamp 34
The lighting control of b is started. Since the paper feed control operation is performed only after the fixing device starts up, even if control data on the paper feed control operation is acquired after the lighting control of the halogen lamp 34b is started, the start-up time of the image forming apparatus is adversely affected. Has no effect. Also, the sequence control board 1
After the fixing control is started, control data other than the fixing control is downloaded from the controller board 2 to prepare for the start of the image forming operation.

FIGS. 7 and 8 are flowcharts showing main operations in the image forming apparatus of the present invention. FIG. 7A shows an operation of selecting a fixing control method based on the temperature of the fixing device when returning from the energy saving mode to the normal mode. In the figure, when returning from the energy saving mode to the normal mode, power supply to the sequence control board 1 is started (S1), and the sequence control board 1 including the CPU 1a is initialized (S2). Next, reference value data (K1 shown in FIG. 5) stored in the ROM 1b of the sequence control board 1 is recognized (S3). Further, the temperature detecting element 5
Then, the temperature of the fixing device 34 is detected (S4), and the magnitude of the detected value is compared with the already recognized reference value data K1 (S5). If the detected value is larger than the reference value data K1 (S5 Yes), the process proceeds to step S7, and if the detected value is smaller than the reference value data K1 (S5 No), lighting control of the halogen lamp 34b by on / off control is started. Then (S6), the process proceeds to step S7. In step S7, the frequency measurement of the commercial power supply is started and the frequency is set to 50 Hz.
It is checked whether it is (S8). If the frequency is 50 Hz (S8 Yes), the frequency stored in the ROM 1b is 50 Hz.
Hz phase control data is read (S9), and the process proceeds to step S11. If the frequency is not 50 Hz, the frequency is determined to be 60 Hz (S8 No), the phase control data for 60 Hz stored in the ROM 1b is read (S10), and the process proceeds to step S11. Step S11
Then, the phase control of the halogen lamp 34b is started based on the read phase control data. FIG. 7B is a flowchart showing an operation of shifting from the normal mode to the energy saving mode. In the figure, in the normal mode of the image forming operation state or the standby state (S12), it waits for a timeout of the standby state or a command to shift to the energy saving mode from the operation unit (S13).
No). Then, when a time-out or a command of a shift instruction is issued (S13 Yes), the sequence control board 1
Is temporarily transferred to the RAM 2b of the controller board 2 (S14). Thereafter, the sequence control board 1 issues a control data transfer completion signal to the controller board 2 (S15). The controller board 2 that has received this signal issues an output control signal to the DC power supply 6 (S16), stops power supply to the sequence control board 1, and ends the transition to the energy saving mode (S17).

FIG. 8 is a flow chart showing that, when returning from the energy saving mode to the normal mode, sequence control is executed in order from the highest priority required for the return. In the figure, it is determined whether or not there is an external command input for returning from the energy saving mode to the normal mode (S20), and if there is an external command input (S20).
20 Yes), the shift to the normal mode is started (S2)
1). In the transition to the normal mode, first, an output control signal is issued from the controller board 2 to the DC power supply device 6, and power supply to the sequence control board 1 is started (S2).
2). Thereafter, the sequence control board 1 performs an initialization operation of the CPU 1a and the like (S23), and then downloads control data related to fixing corresponding to high-priority sequence control from the controller board 2 and transfers it to the sequence control board 1 (step S23). S24). Further, it is asked whether or not the transfer of the control data relating to the fixing is completed (S25). If the transfer is completed (Yes in S25), the frequency data of the commercial power source is selected from the control data transferred to the sequence control board 1. Is extracted (S26), and it is checked whether or not the frequency is 50 Hz (S27). If the frequency is 50 Hz (S
27 Yes), 50 Hz stored in ROM 1 b
Is read out (S28), and step S28
Proceed to 30. If the frequency is not 50Hz,
It is determined that the frequency is 60 Hz (No in S27), the phase control data for 60 Hz stored in the ROM 1b is read (S29), and the process proceeds to step S30. Step S30
Then, the phase control of the halogen lamp 34b is started based on the read phase control data. Further, after the start of the phase control of the halogen lamp 34b, the remaining control data other than the control data relating to the fixing is transferred from the controller board 2 to the sequence control board 1 (S31).

[0015]

As described above, according to the first aspect of the present invention,
It has become possible to provide an image forming apparatus having two different characteristics with respect to the temperature control of the fixing device. Claim 2
According to the invention of the first aspect, in addition to the invention of the image forming apparatus of the first aspect, it is possible to provide an image forming apparatus in which the temperature rise of the fixing device is accelerated or the flicker phenomenon is suppressed. . According to the third aspect of the invention, in addition to the image forming apparatus of the second aspect, when the power of the image forming apparatus is turned on, the rise of the temperature of the fixing device is accelerated, and when returning from the energy saving mode to the normal mode, flicker is performed. An image forming apparatus capable of suppressing the phenomenon and stabilizing the function of the apparatus can be provided. According to the invention of claim 4, in addition to the invention of the image forming apparatus of claim 2, the effects of shortening the return time from the energy saving mode to the normal mode and suppressing the flicker phenomenon are adapted to the state of the apparatus. An image forming apparatus can be provided. According to the invention of claim 5, in addition to the invention of the image forming apparatus of claim 4, when the temperature of the fixing device is lower than a predetermined temperature when returning from the energy saving mode to the normal mode, the return time is shortened. When the temperature is higher than a predetermined temperature, the flicker phenomenon is improved, and an image forming apparatus satisfying the rise time of the temperature of the fixing device can be provided. According to the invention of claim 6, claim 3, 4, or 5
In addition to the invention of the image forming apparatus described above, it is possible to provide an image forming apparatus in which the fixing device can be started up early and the time required to return from the energy saving mode to the normal mode is reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of a digital copying apparatus to which the present invention is applied.

FIG. 2 is a block diagram showing a main part for performing temperature control of a fixing device of the image forming apparatus according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating on / off control of a heater by a first-type fixing control unit in the image forming apparatus according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram illustrating phase control of a heater by a second type fixing control unit in the image forming apparatus according to the exemplary embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating a relationship between a lighting time of a heater of the fixing device and a temperature of the fixing device.

FIG. 6 is a configuration diagram showing a main part of an operation unit of the image forming apparatus according to the embodiment of the present invention.

FIG. 7A is a flowchart illustrating an operation of selecting a fixing control method based on the temperature of the fixing device when returning from the energy saving mode to the normal mode in the image forming apparatus according to the embodiment of the present invention; 3) is a flowchart showing an operation of shifting from the normal mode to the energy saving mode in the image forming apparatus according to the embodiment of the present invention.

FIG. 8 is a flow chart showing that in the image forming apparatus according to the embodiment of the present invention, when returning from the energy saving mode to the normal mode, sequence control having higher priority is executed in order.

[Explanation of symbols]

1 sequence control board, 1a CPU, 1b ROM,
1cRAM, 1e First fixing control unit (first type fixing control unit), 1f Second fixing control unit (second type fixing control unit), 2 controller board, 3 heater control element, 4 photocoupler, 5 temperature detection Element, 6 DC power supply, 7 operation section, 7k mode clear / preheat key,
34 Halogen lamp

Claims (6)

[Claims] An image forming apparatus capable of shifting from a normal mode to an energy saving mode in order to reduce power consumption in a standby state, a first type of fixing control means for controlling a temperature of the fixing device, and a second type of fixing control means. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, wherein
The first type of fixing control means performs on / off control in which the supply power is turned on and off by changing the time, and the second type of fixing control means turns on or off at a zero crossing point of the frequency of the power supply, An image forming apparatus, wherein phase control is performed by changing a phase angle during energization. 3. The image forming apparatus according to claim 2, wherein
An image forming apparatus, wherein the temperature control by the first type fixing control unit is performed when the power of the image forming apparatus is turned on, and the temperature control by the second type fixing control unit is performed when returning from the energy saving mode to the normal mode. 4. The image forming apparatus according to claim 2, wherein
Based on the temperature of the fixing device when returning from the energy saving mode to the normal mode, the first type of fixing control unit or the second type of fixing control unit is used.
An image forming apparatus wherein temperature control is performed by selecting a fixing control unit of a system. 5. The image forming apparatus according to claim 4, wherein
When the temperature of the fixing device at the time of returning from the energy saving mode to the normal mode is lower than the predetermined temperature, the first type of fixing control means is selected. When the temperature is higher than the predetermined temperature, the second type of fixing control is selected. An image forming apparatus, wherein a temperature is controlled by selecting a unit. 6. The image forming apparatus according to claim 3, wherein upon returning from the energy saving mode to the normal mode, priorities are assigned to the sequence controls required for the return, and the sequence controls are executed in order from the highest priority. An image forming apparatus.