JP4365052B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic image forming apparatus that heats and fixes an unfixed toner image, such as a copying machine, a laser printer, and a facsimile, and more particularly to an image forming apparatus having an energy saving mode.
[0002]
[Prior art]
Conventionally, an invention using a solar cell as means for reducing the power consumption of an image forming apparatus is disclosed in JP-A-7-271249. Japanese Patent Application Laid-Open No. 10-164293 and Japanese Patent Application Laid-Open No. 2001-69687 disclose an invention for starting a solar cell during standby.
[0003]
[Problems to be solved by the invention]
Japanese Patent Application Laid-Open No. 7-271249 reports a technique for supplying power from a solar cell as means for reducing power consumption of an image forming apparatus. However, an image forming apparatus provided with a fixing heater generally requires several hundred watts or more of power consumption for printing even in a desktop type machine. In order to supply such large power from a solar cell, a large size is required. It is necessary to install a solar cell panel, and there is a cost problem.
[0004]
In Japanese Patent Laid-Open Nos. 10-164293 and 2001-69687, the power consumption during standby is supplied from a power source stored by a solar cell, and the power source is a commercial power source when the amount of stored power is insufficient. Technology has been reported in which electricity is stored from the main power source fed from the power source. Here, in an image forming apparatus provided with a fixing heater, the energy saving power consumption value at the time of standby is defined by international regulations such as ZESM and ENERGY-STAR. This is a very strict value, but it is obliged to comply.
[0005]
As a result, there is a problem that when the power source stored by the solar cell in standby mode is charged from the main power source due to insufficient storage amount, the corresponding load increases, resulting in an increase in power consumption. is there.
[0006]
SUMMARY An advantage of some aspects of the invention is to provide an image forming apparatus that can solve the above-described problems of the related art as a whole and further reduce the power consumption in the energy saving mode.
[0007]
In order to achieve the above object, the invention according to claim 1 includes a main power source that supplies power to each part of the apparatus main body, a solar cell, and a secondary battery that is charged by the main power source or the solar cell, Further, the image forming apparatus includes control means for controlling the supply of power to each part of the apparatus main body by the secondary battery in the energy saving mode, and controlling the power supply state of the secondary battery. a power threshold detection means for monitoring, wherein, when the voltage of the secondary battery to the energy saving mode when that is below a threshold value that is lowered is detected in the power threshold detection means, the two characterized by blocking the respective portions path for supplying power to the apparatus body from the following cell, a path for supplying power from the secondary battery to the energy saving mode there are a plurality of said power threshold detection hand The threshold voltage of the secondary battery is set to the number of paths within, said control means stepwise according to drop condition of voltage, the most important features of the image forming apparatus characterized by blocking the path And
[0009]
According to a second aspect of the present invention, when the voltage drop of the secondary battery continues regardless of the step-by-step interruption of the path and the voltage drops below a certain threshold, the control means switches from the secondary battery to the main power source. the image forming apparatus according to claim 1 to continue the energy-saving mode by switching the operation and main features.
[0010]
According to a third aspect of the present invention, when the secondary battery is charged during the energy saving mode and the voltage rises and exceeds a certain threshold value, the control means transfers the secondary battery from the main power source. The image forming apparatus according to claim 2, wherein the operation is switched to continue the energy saving mode.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a power supply unit of an image forming apparatus according to an embodiment of the present invention. This power supply section is roughly divided into a power supply circuit section 1 including a main power supply and a secondary battery, a commercial power supply 2, a solar battery 3, and a CPU 4.
[0012]
The power supply circuit unit 1 is configured as follows. The main power supply 5 is a switching power supply, and rectifies an AC voltage from the commercial power supply 2 to generate a DC voltage (5V, 24V, etc.). The secondary battery 6 is charged from the main power supply 5 via the solar battery 4 and the auxiliary charging circuit 8 and generates a DC voltage when the image forming apparatus is in the energy saving mode. The voltage threshold detection circuit 7 reads the voltage value supplied from the secondary battery 6 and monitors the power supply state of the secondary battery 6. The auxiliary charging circuit 8 supplementarily charges the secondary battery 6 with the DC voltage rectified via the main power source 5 during the operation of the image forming apparatus. When the signal is input from the voltage threshold detection circuit 7 when the image forming apparatus enters the energy saving mode, the control circuit 9 cuts off the path of DC voltage such as 5V and 24V supplied from the secondary battery 6 to each part of the apparatus. Output a signal. The power cutoff circuits 10, 11, and 12 are circuits that mechanically cut off the power supply path, and cut off the path by a signal from the control circuit 9. The CPU 4 switches the output of the main power source 5 and the secondary battery 6 in the operation mode and the energy saving mode of the image forming apparatus.
[0013]
The operation of the power supply unit configured as described above will be described below. The solar battery 3 generates electric power according to the intensity of the irradiated sunlight or the illumination level of the room lighting at daytime, and stores the secondary battery 6 of the power supply unit 1. The secondary battery 6 serves as a power source for supplying power to each part of the apparatus when the image forming apparatus enters the energy saving mode. When the power source of the image forming apparatus is turned on, the main power source 5 which is a switching power source is first activated to start outputting DC voltage to each part of the apparatus serving as a load. In the present embodiment, the voltage serving as the load output is 24V: drive system, 5V: engine control system, 3.3V: LD system, 3.3V: controller system. At this time, the secondary battery 6 is charged from the solar battery 3 and is charged from the main power supply 5 via the auxiliary charging circuit 8, but is not output under the control of the CPU 4. Thereafter, as long as the operation state in which the image forming apparatus performs the printing operation continues intermittently, the power supply unit maintains this state.
[0014]
Next, when the image forming apparatus enters the energy saving mode, a control signal is output from the CPU 4 and the secondary battery 6 is activated. Immediately thereafter, the operation of the main power supply 5 is stopped by the control signal from the CPU 4. Here, as a method for stopping the main power supply, the logic of the signal input to the control LSI of the switching power supply may be changed. Since the main power supply 5 is stopped, power storage performed in the secondary battery 6 through the auxiliary charging circuit 8 during operation is stopped, and power storage in the secondary battery 6 is performed only from the solar battery 3. The activated secondary battery 6 starts to output DC voltage to each part of the apparatus in the same manner as the main power supply 5 during operation. However, the drive system, engine control system, and LD system are in a stopped state in accordance with the energy saving mode. The load is very small compared to that during operation. Generally, the power consumption in the energy saving mode is 10 W or less, and the secondary battery 6 alone can be used for a long time.
[0015]
In this way, the power source activated in the energy saving mode state is the secondary battery 6, and the main power source 5 fed from the commercial power source 2 is stopped, so that the power consumption has achieved almost 0W. . Further, since the secondary battery 6 is charged from the main power source 5 and the solar battery 3 in the operation mode, it can be used for a relatively long time in the energy saving mode.
[0016]
The electric capacity of the secondary battery 6 in the energy saving mode is constantly monitored by the voltage threshold detection circuit 7. When this energy saving mode continues for a long time and the irradiation state to the solar cell 3 deteriorates for some reason, the secondary battery 6 is no longer charged, and as a result, the voltage of the secondary battery 6 gradually decreases. To go. The voltage threshold detection circuit 7 monitors this, and sends a signal to the control circuit 9 when the voltage of the secondary battery reaches a certain threshold (a). Upon receiving this signal, the control circuit 9 first mechanically shuts off the 24V: drive system by sending a signal to the power shut-off circuit 10 among the loads output by the secondary battery 6. 24V: Since a very small amount of current flows in the drive system even in the energy saving mode, the load applied to the secondary battery 6 is reduced by mechanically cutting off the load path, and the voltage is gradually reduced. Thus, the life of the secondary battery 6 is extended.
[0017]
The load connected in this state is 5V: engine control system, 3.3V: LD system, 3.3V: controller system, but the voltage of the secondary battery 6 further decreases due to these loads, When a threshold value (b) lower than (a) is reached, a signal is sent again to the control circuit 9, and this time 5V: mechanically shuts off the power shut-off circuit 11 of the engine control system. Similarly, when the voltage of the secondary battery 6 reaches a certain threshold value (c) lower than (b), the 3.3 V: LD power supply cutoff circuit 12 is mechanically shut off. 3.3V: Since the controller system requires power supply even in the energy saving mode, the load path is not cut off. Therefore, 3.3V: The CPU 4 supplied with power from the controller system is operating even in the energy saving mode. The control circuit 9 that shuts off the shut-off circuit is controlled by the CPU 4 and performs shut-off according to the signal of the voltage threshold value detection circuit 7 only in the energy saving mode.
[0018]
In this way, the load applied to the secondary battery 6 is cut off step by step, so that the power required for cutting off is lighter than when all the loads are cut off at one time. Can prolong life.
[0019]
Further, even when all the loads that can be shut off by the shut-off circuit are shut off, the voltage of the secondary battery 6 is lowered. At this time, the voltage of the secondary battery 6 is set to a certain threshold value (d) lower than (c). When the voltage reaches, the voltage threshold detection circuit 7 sends a signal to the CPU 4. Upon receiving this signal, the CPU 4 stops the output of the secondary battery 6 and starts the main power supply 5. At this time, the interrupting circuits 10, 11, and 12 may remain in an interrupted state. The main power source 5 is 3.3 V, which is a load connected in this state, and supplies power to the controller system to continue the energy saving mode. However, in order not to increase the load unnecessary for the main power supply 5, the secondary battery 6 is not charged via the auxiliary charging circuit 8 in the energy saving mode.
[0020]
When the irradiation state on the solar cell 3 is changed well during a series of operations, power storage from the solar cell 3 to the secondary battery 6 is always started. When power storage in the secondary battery 6 is started in this state, the voltage of the secondary battery 6 gradually increases. When the threshold value (d) is reached, the voltage threshold value detection circuit 7 sends a control signal to the CPU 4 again. Upon receiving this signal, the CPU 4 activates the secondary battery 6 and stops the operation of the main power source 5. The secondary battery 6 is 3.3V: supplying power to the controller system to continue the energy saving mode.
[0021]
Thereafter, when the image forming apparatus shifts from the energy saving mode to the operation mode, the CPU 4 sends a control signal to activate the main power source 5 to connect all the interrupted loads to the original state, and the secondary battery 6 The output of is stopped. Thus, by suppressing the start-up time of the main power source 5 in the energy saving mode only when the amount of power stored in the secondary battery 6 is insufficient, the power consumption during energy saving when viewed in total can be reduced.
[0022]
【The invention's effect】
According to the present invention, it is possible to reduce the load applied to the secondary battery and to maintain the energy saving mode by the secondary battery for a long time by cutting off the power supply path from the secondary battery to each part of the device in the energy saving mode. become.
[0023]
In addition, by cutting off the power supply path to each part of the device step by step, the power required for interruption is lighter than that at the same time, reducing the load on the secondary battery and reducing the secondary battery power. There is an effect that the energy saving mode by the battery can be maintained for a long time.
[0024]
In addition, the activation of the main power source during the energy saving mode can be suppressed to the minimum necessary, and the power consumption can be reduced in total.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a power supply unit of an image forming apparatus according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Power supply circuit part 2 Commercial power supply 3 Solar cell 4 CPU (control means)
5 Main power supply 6 Secondary battery 7 Power threshold detection circuit 8 Auxiliary charging circuit 9 Control circuit (control means)
10, 11, 12 Power-off circuit

Claims (3)

A main power source for supplying power to each part of the apparatus main body; a solar cell; and a secondary battery charged by the main power source or the solar cell, and further stopping the operation of the main power source in the energy saving mode. An image forming apparatus including a control unit that performs control to supply power to each unit of the apparatus main body using a secondary battery,
Comprising a power threshold detection means for monitoring the power supply state of the secondary battery,
The control unit, when the voltage of the secondary battery in the power saving mode when it falls below a threshold value that is lowered is detected in the power threshold detection means, the power to each unit of the secondary battery from the apparatus main body It characterized by blocking the path for supplying,
There are multiple paths for supplying power from the secondary battery in the energy saving mode,
An image forming apparatus characterized in that the threshold value of the voltage of the secondary battery is set in the power supply threshold value detecting means by the number of paths, and the control means blocks the paths in a stepwise manner according to a voltage drop state. . Regardless of the stepwise interruption of the path, if the voltage drop of the secondary battery continues and falls below a certain threshold, the control means switches the operation from the secondary battery to the main power source and continues the energy saving mode. The image forming apparatus according to claim 1, wherein: In the energy saving mode, when the secondary battery is charged and the voltage rises and exceeds a certain threshold, the control means switches the operation from the main power source to the secondary battery and continues the energy saving mode. The image forming apparatus according to claim 2, wherein:

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