JP2003122200A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the consumption of power furthermore than in the prior art and save energy during a standby period by separating a power supply part for a fixing part from a power supply part for control parts and supplying the power to only the fixing part. SOLUTION: The image forming apparatus having the fixing part that forms an image, is characterized in that the power supply part that supplies power to the fixing part is separated from the power supply part that supplies power to the control parts. When an operation is not performed, power is supplied to only the fixing part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser printer,
The present invention relates to an image forming apparatus such as a copying machine, a fax machine, and a complex machine thereof, and more specifically, to an image forming apparatus having a fixing unit.

[0002]

2. Description of the Related Art In order to deepen the understanding of the prior art of the present invention, a block diagram of a conventional general power supply will be shown first with reference to FIG. First, AC power is input to the AC / DC converter 1. The AC / DC converter 1 outputs the DC power used in the device from the input AC power. At this time, the AC / DC converter 1 is controlled by the converter control circuit 2. Generally, this control is called chopping control. That is, when the chopping control is stopped, the converter vibration is also stopped, and as a result, the DC output is not output. Thereafter, the output of the DC power source output from the converter is supplied to each load. Under such a premise, JP-A-59-201078 is known as a prior art of the present invention. The publication discloses a proposal of an image forming apparatus having a mode for suppressing power consumption during standby, for example, a residual heat mode for energy saving. However, in the invention of Japanese Patent Laid-Open No. 59-201078, it is necessary to lower the control temperature of the fixing unit or turn off the fixing unit in order to suppress the electric power, and therefore, when performing the next job. However, there is a fatal problem in the fixing device in that it takes a long time for the temperature of the fixing unit to reach an appropriate temperature. On the other hand, as another conventional technique, Japanese Patent Laid-Open No. 5-333636
The publication is known. The publication discloses a technique of cutting off power supply to an unnecessary load through a relay during standby in order to suppress power consumption. FIG. 2 shows a power supply block diagram proposed in the above-mentioned Japanese Patent Laid-Open No. 5-333636. The DC power source output from the AC / DC converter 1 is divided into a load required and a load unnecessary during standby. A relay 3 is provided between the unnecessary load and the AC / DC converter 1, and the main control turns the relay 3 ON / OFF. However, even with this method, the AC / DC converter is always AC
Power is being input, and power will continue to be consumed.

[0003]

As described above, in the above-mentioned fixing device of the prior art, it takes a long time for the temperature of the fixing portion to reach an appropriate temperature, and in addition, power is consumed even during standby. There is a fatal problem. Therefore, the present invention has been made to solve the above problems.
In addition, by separating the power supply unit to the fixing unit from the power supply to other control units and only supplying the power to the fixing unit, the power consumption is further suppressed as compared with the above-mentioned conventional technique, and energy saving during standby is performed. The purpose is to Secondly, power supply to the main CPU is separated from other control units, and only the CPU and the fixing control unit are energized except during operation, so that only the minimum necessary power is consumed and the fixing control is performed more safely. The purpose is to do. Thirdly, the fixing control section has an independent CPU, and only this CPU operates when not in operation, so that it is possible to further reduce power consumption while ensuring safety. Fourthly, the independent CPU of the fixing control section has an interface with the outside, so that the image forming apparatus in the standby state can be accessed anytime from a distance, and the operability is improved. The purpose is to let.

[0004]

In order to achieve the above object, the present invention according to claim 1 is an image forming apparatus having a fixing portion for forming an image, and further includes a power supply portion for supplying to the fixing portion. The main feature of the image forming apparatus is that it is separated from the electric power supply unit for supplying electric power to the control unit, and only supplies electric power to the fixing unit except during operation. According to a second aspect of the present invention, the main feature of the image forming apparatus according to the first aspect is that the power supply to the main CPU is separated from other control units, and only the CPU and the fixing control unit are energized except during operation. To do. The present invention according to claim 3 has a main feature of the image forming apparatus according to claim 1, which has an independent CPU in the fixing control unit and operates only this CPU except during operation. The present invention according to claim 4 is characterized mainly in the image forming apparatus according to claim 3, wherein an independent CPU is provided in an independent CPU of the fixing control unit.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of a first embodiment of the present invention. The conventional AC / DC converter 1 shown in FIG. 7 is separated into a fixing AC / DC converter 4 and an AC / DC converter 5 for other loads. For fixing A
The C / DC converter 4 supplies power only to the fixing control circuit 6, and then supplies power to the fixing unit 7, which is a load. For other loads 8, AC / DC for other loads
It is supplied from the converter 5. Further, each converter has converter control circuits 9 and 10, respectively, and performs chopping control of the converter. Main control CPU1
1 is connected to this converter, except when in operation
Outputs an operation stop signal for the converter control circuit. As a result, this converter is stopped and the output of the DC power supply is also stopped. As a result, the power consumption of loads other than the fixing control becomes zero, and energy saving can be achieved.
FIG. 2 shows an example of the fixing control circuit 6 in this case. The fixing heater 12 is provided with a thermistor 13 for detecting its temperature, and when the output voltage thereof exceeds a certain fixed value,
The photo coupler 14 is turned off, and as a result, the triac 15 is turned off and the fixing heater 12 is turned off. afterwards,
As the temperature of the fixing heater 12 decreases, the thermistor 13
When the output voltage of 1 is lower than a certain value, the output of the comparator 16 changes and the photocoupler 14 is turned on. As a result, the triac 15 is turned on, the fixing heater 12 is turned on, and the temperature rises. Hereinafter, this operation will be repeated. It should be noted that this fixed value is set in advance so as to reach the fixing temperature required during operation. further,
This value does not necessarily have to be the temperature required during operation, and can be set higher or lower. For these reasons, the image forming apparatus of the present invention can keep the power consumption low while controlling the temperature of the fixing unit.

FIG. 3 shows a block diagram of a second embodiment of the present invention. The parts having the same functions as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals. In FIG. 3, the main control CPU 11 is connected to the fixing AC / DC converter 4. Therefore, the main CPU 11 can continue to operate even when it is not in operation, and finer fixing control can be performed. Further, the temperature of the fixing heater 12 described in FIG. Fixing heater 12
It becomes possible to perform the heater control more safely by cutting off the power supply to the heater. FIG. 4 shows a block diagram of a third embodiment of the present invention. Fixing control CPU 17 for fixing control
The fixing control CPU 17 is connected to the fixing AC / DC converter 4, and the main control CPU 11 is connected to the AC / DC converter 5 for other loads.
The fixing control CPU 17 performs fixing control on the main control CPU 1
Independent of 1. Since the fixing control CPU 17 does not perform any other control, it requires a much smaller capacity than the main control CPU 11 and consumes less power than the main control CPU 11.
Can be less. As a result, it is possible to further reduce power consumption.

FIG. 5 shows a block diagram of a fourth embodiment of the present invention, and FIG. 6 shows a flow chart at that time. Fixing control C
The PU 17 has an operation request signal I / F from the outside. As an example of the operation request signal from the outside, the energy saving release S
W, print command from printer controller, FAX
Output command from. The operation will be described below with reference to the flowchart of FIG. The main control performs a normal print operation. First, start print job (S1),
After the print job is completed (S2), the fact that the operation is completed is transmitted to the fixing control CPU 17 (S3). On the other hand, the fixing control CPU 17 performs normal fixing temperature control (S
11). When the operation end signal is received from the main control CPU 11 (S12), the converter stop signal is output (S13). With this signal, converters other than the energy-saving converter are stopped, and DC power supply to loads other than the heater control unit is stopped. After that, the operation request signal from the outside is monitored, and when the operation request signal comes from somewhere (S14), the converter ON signal is output (S1).
5). As a result, all the converters operate, and as a result, they are in the operable state. As a result, for example, PPC
Even in the case of a multifunction machine such as a fax machine or a printer, the printing operation can be performed from a remote place, and the operability can be improved.

[0008]

According to the first aspect of the present invention, the power supply unit for the fixing unit is separated from the power supply for the other control units, and only the power supply for the fixing unit is performed. Furthermore, it is possible to reduce power consumption and save energy during standby. According to the invention of claim 2,
Separate the power supply to the main CPU from other control units,
By energizing only the CPU and the fixing control unit except during operation, it is possible to consume the minimum necessary power and perform the fixing control more safely. According to the third aspect of the present invention, the fixing control unit has an independent CPU, and only this CPU operates when not in operation, so that it is possible to further reduce power consumption while ensuring safety. According to the invention described in claim 4, the independent CP of the fixing control unit
Since the U has an I / F with the outside, the image forming apparatus in the standby state can be accessed anytime from a distance, and the operability can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a block diagram of a fixing control circuit according to the first embodiment of the present invention.

FIG. 3 is a block diagram of a second embodiment of the present invention.

FIG. 4 is a block diagram of a third embodiment of the present invention.

FIG. 5 is a block diagram of a fourth embodiment of the present invention.

FIG. 6 is a flowchart of a fourth embodiment of the present invention.

FIG. 7 is a block diagram of a general power supply.

FIG. 8 is a block diagram of a power supply according to a conventional technique of the present invention.

[Explanation of symbols]

4 AC / DC converter for fixing, 5 AC / DC converter for other loads, 6 fixing control circuit, 7 fixing unit, 8 other load, 9, 10 converter control circuit, 11 main control CPU, 12 fixing heater, Thirteen
Thermistor, 14 Photocoupler, 15 Triac, 16 Comparator, 17 Fixing control CPU

Claims (4)

[Claims] 1. An image forming apparatus having a fixing unit for forming an image, wherein a power supply unit for supplying to the fixing unit is separated from a power supply unit for supplying to another control unit, and except when in operation. An image forming apparatus characterized in that only power is supplied to a fixing unit. 2. The image forming apparatus according to claim 1, wherein power supply to the main CPU is separated from other control units, and only the CPU and the fixing control unit are energized except during operation. 3. The image forming apparatus according to claim 1, wherein the fixing control section has an independent CPU, and only the CPU operates when not in operation. 4. The independent CPU of the fixing controller has an interface with the outside.
The image forming apparatus described.