JP2006286321A - Fuel cell system, electronic apparatus equipped with the same, and image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of supplying stable power to an electronic apparatus, having wide fluctuations of load, such as an image formation device that does not use alcohol concentration sensor. <P>SOLUTION: In a fuel cell of this application, alcohol concentration in a fuel is calculated from the power and temperature of the fuel cell; a fuel pump and/or a water pump are/is operated, based on the result thereof to control the alcohol concentration of a mixing tank. This fuel cell system is provided with a circuit means where an output current on the fuel cell side or an output current is kept constant, even if the load of an external electronic apparatus or the like changes. Accordingly, even if a current, consumed on the electronic apparatus side is markedly changed, the output current of the fuel cell will not be influenced by it, and the power of the fuel cell results in setting to a constant value, determined by the temperature and the alcohol concentration of the fuel cell. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell system, and more particularly to a fuel cell system using alcohol as a fuel. The present invention further relates to an electronic apparatus and an image forming apparatus provided with such a fuel cell system.

  A fuel cell is a power supply device that can obtain energy by utilizing a reaction when water is generated from hydrogen and oxygen. Many types of fuel cells have been developed and put to practical use.

  One type of fuel cell is a fuel cell that uses alcohol as the fuel (for example, a direct methanol fuel cell (DMFC)), which is expected to be used as a power source for vehicles and electronic devices. ing.

  In such an alcohol-based fuel cell, a liquid mixed fuel containing an alcohol such as methanol and water is usually circulated and used while being stored in a tank or the like. The mixed fuel is supplied to the fuel cell, discharged from the cell, and then returned to the tank. However, the alcohol in the mixed fuel is consumed as fuel in the cell. The alcohol concentration inside gradually decreases. However, since the output voltage and output current of the fuel cell depend on the alcohol concentration in the fuel, when the alcohol concentration in the supplied fuel decreases, the output also decreases.

Therefore, in order to stably operate the fuel cell output, it is necessary to monitor and control the alcohol concentration of the mixed fuel in the tank. Usually, in order to enable such control, an alcohol sensor is installed in the tank to measure the alcohol concentration. When the alcohol concentration in the tank drops, the required amount of alcohol is supplied to the tank from another alcohol storage source. (See Patent Document 1).
JP 11-352089 A

  However, when the alcohol sensor is installed, it is necessary to secure the space inside the fuel cell system, and there is a problem that the entire system cannot be reduced in size and weight. Moreover, since the alcohol sensor itself is expensive, there is a problem that the use of the sensor leads to high cost of the fuel cell system.

  Some electronic devices have a large fluctuation in power consumption during use. For example, in an electrophotographic image forming apparatus, a large amount of power is instantaneously consumed when the fixing roller is turned on during heat fixing. In an inkjet image forming apparatus, the current fluctuates during a printing operation, and the current increases rapidly when the carriage starts moving or when a recording medium such as paper starts to be fed. Therefore, when the fuel cell system is used as a power source for these devices, even if the alcohol concentration is controlled to be constant by a sensor, when a large load is applied, a voltage drop corresponding to the current value occurs in the fuel cell, and the output There is a problem that the voltage fluctuates.

  The present invention has been made in view of the problems as described above, and can provide a stable output even to an electronic apparatus having a large load fluctuation such as an image forming apparatus without using an alcohol concentration sensor. An object is to provide a possible fuel cell system.

In order to solve the above problems, in the present invention,
A fuel cell main body, a storage tank for alcohol as a fuel source, a mixing tank connected to the storage tank via a fuel pump and supplying fuel containing alcohol and water to the fuel cell main body, and operation of the fuel pump A fuel cell system having control means for controlling the fuel cell output by controlling the fuel pump, wherein the control means controls the operation of the fuel pump based on the temperature and output voltage or output current of the fuel cell main body. A fuel cell system is provided.

In the present invention,
A fuel cell main body, a storage tank for alcohol as a fuel source, a mixing tank connected to the storage tank via a fuel pump and supplying fuel containing alcohol and water to the fuel cell main body, and operation of the fuel pump A fuel cell system for controlling the fuel cell output and controlling the output of the fuel cell, connected to a control circuit of an external device, and driving the external device, the fuel cell system comprising a load fluctuation of the external device Regardless of this, it has circuit means for maintaining the output current from the fuel cell body constant, and the control means controls the operation of the fuel pump based on the temperature and output voltage of the fuel cell body. A fuel cell system is provided.

Furthermore, in the present invention,
A fuel cell main body, a storage tank for alcohol as a fuel source, a mixing tank connected to the storage tank via a fuel pump and supplying fuel containing alcohol and water to the fuel cell main body, and operation of the fuel pump A fuel cell system for controlling the fuel cell output and controlling the output of the fuel cell, connected to a control circuit of an external device, and driving the external device, the fuel cell system comprising a load fluctuation of the external device Regardless of this, it has circuit means for maintaining the output voltage from the fuel cell body constant, and the control means controls the operation of the fuel pump based on the temperature and output current of the fuel cell body. A fuel cell system is provided.

  In such a fuel cell system, it is possible to predict the fuel alcohol concentration from the value and temperature of the output voltage or output current of the fuel cell body without installing an alcohol sensor. In addition, since the fuel cell system of the present invention is provided with circuit means for keeping the output current or voltage constant, even if the current consumed on the external device side changes significantly, the fuel cell side is affected by this. Absent. Therefore, even when used as a power supply source of an external device having a heavy load fluctuation, the fuel alcohol concentration can be predicted in the same manner.

  In the fuel cell system of the present invention, the circuit means for maintaining the output current constant is composed of a constant current device and a power storage device, and the constant current device is located on the most upstream side when viewed from the output side of the fuel cell body. Connected to the fuel cell body in series with the control circuit of the external device, the power storage device is configured such that the current supplied from the fuel cell side via the constant current device and the current from the power storage device merge, May be connected in parallel with the fuel cell body.

  Alternatively, in the fuel cell system of the present invention, the circuit means for maintaining the output current constant includes a current sensor, a power storage device, and a current control device, and the current sensor is the most upstream side when viewed from the output side of the fuel cell body. In addition, the power storage device is connected in series with the control circuit of the external device, and the current supplied from the fuel cell side through the current sensor and the current from the power storage device are merged and supplied to the control circuit of the external device. Connected in parallel with the fuel cell main body, the current control device is connected in series with the power storage device, upstream of the power storage device as viewed from the fuel cell output side, and according to the current signal from the current sensor, The charge / discharge amount of the power storage device may be controlled. In this case, a diode that bypasses the discharge current from the power storage device from the current control device may be further provided.

  In the above fuel cell system, the circuit means for making the output current constant includes a switch circuit configured by a constant current device and a power storage device and connected in parallel with the constant current device, and the control means includes a predetermined unit. It is also possible to close the switch circuit at the time interval and switch the current flow from the fuel cell main body on the constant current device and the switch circuit side. Alternatively, the constant current device may be short-circuited at predetermined time intervals by the control means.

  Thereby, the power loss which arises with a constant current apparatus can be suppressed significantly.

  In the fuel cell system of the present invention, the circuit means for maintaining the output voltage constant is composed of a current sensor, a power storage device, and a current control device, and the current sensor is the most upstream side when viewed from the output side of the fuel cell body. In addition, the power storage device is connected in series with the control circuit of the external device, and the current supplied from the fuel cell side through the current sensor and the current from the power storage device are merged and supplied to the control circuit of the external device. Connected in parallel with the fuel cell main body, the current control device is connected in series with the power storage device, upstream of the power storage device as viewed from the fuel cell output side, and according to the output voltage of the fuel cell main body, The charge / discharge amount of the power storage device may be controlled. In this case, a diode that bypasses the discharge current from the power storage device from the current control device may be further provided.

  Furthermore, in the fuel cell system of the present invention, when the diode is installed, the current control device may be short-circuited at predetermined time intervals by the control means.

  Thereby, the power loss which arises with a current control apparatus can be suppressed significantly.

  Note that the power storage device used in the present invention may be a secondary battery.

  Furthermore, the present invention provides an electronic device including the above-described fuel cell system, for example, an image forming apparatus.

  According to the present invention, it is possible to calculate the alcohol concentration without installing an alcohol concentration sensor, and stable power supply from the fuel cell system is possible. Further, even when the fuel cell system of the present invention is used as a power supply source of an electronic device whose load fluctuates greatly, stable power supply can be similarly achieved. Further, the fuel cell system can be reduced in size and weight, and the cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the following FIG. 1, a direct methanol fuel cell (DMFC) will be described as an example. However, a fuel cell using a liquid such as ethanol or propanol as a fuel may be used.

  FIG. 1 shows a general configuration example of the fuel cell 3. The fuel cell 3 includes a fuel cell main body 5, a fuel cell control unit 52, and other auxiliary machines. Other auxiliary machines include fuel tank 17, fuel pump P1, mixing tank 19, fuel supply path 27, circulation pump P2, blower P3, condenser 31, cooling air 37, fan 35, water tank 20, water pump P4, and the like. Is included.

  The fuel cell control unit 52 performs overall control of the fuel cell 3. The fuel cell main body 5 includes an anode (fuel electrode) 7 having a catalyst for electrochemical oxidation of methanol (methanol oxidation electrode catalyst) and a cathode having a catalyst for selective electrochemical reduction of oxygen (oxygen reduction electrode catalyst). Between the (air electrode) 9, an electrolyte membrane 11 is provided. The fuel cell main body 5 may be a single cell, but normally a stack in which single cells are connected in series is used in order to secure a necessary voltage.

  Among the auxiliary machines, the fuel tank 17 for storing methanol is connected to the mixing tank 19 via the fuel pump P1, and the methanol in the fuel tank 17 is transported to the mixing tank 19 when the fuel pump P1 operates. .

  The mixing tank 19 contains a mixed liquid of methanol supplied from the fuel tank 17 by the fuel pump P1 and water recovered from the fuel cell main body 5. A circulation pump P <b> 2 is arranged in the fuel supply path 27 that connects the mixing tank 19 and the fuel cell main body 5, and this pump supplies the aqueous methanol solution in the mixing tank 19 to the anode side of the fuel cell main body 5. Further, air is supplied to the cathode side of the fuel cell body 5 by the blower P3.

  In the fuel cell main body 5 supplied with the aqueous methanol solution and air, electric power is generated between the anode 7 and the cathode 9, carbon dioxide is generated on the anode side, and water is generated on the cathode side. Exhaust gas from the anode side is collected in the mixing tank 19. Further, since the temperature inside the fuel cell is high, the water generated on the cathode side is partly water vapor, but is cooled when passing through the aggregator 31, separated into water and air, and returned to the water tank 20. . The aggregator 31 is cooled by cooling air 37 made by the fan 35. The water collected in the water tank 20 is used to dilute the methanol supplied from the fuel tank 17 to the mixing tank 19, and other unnecessary water is discharged from the mixing tank 19 together with carbon dioxide as water vapor.

  When the amount of aqueous methanol solution in the mixing tank 19 decreases, the water pump P4 operates intermittently to supply water from the water tank 20 to the mixing tank 19. Further, when methanol is consumed by power generation and the concentration becomes low, the fuel pump P <b> 1 operates intermittently and high concentration methanol is supplied into the mixing tank 19.

  Normally, a methanol concentration sensor is used to measure the methanol concentration in the mixing tank 19.

  In contrast, the present invention is characterized in that the methanol concentration in the mixing tank 19 can be controlled without using an expensive methanol concentration sensor.

  The features of the present invention will be described below.

  In the present invention, when factors affecting fuel cell output characteristics such as temperature and load are constant, the alcohol concentration is determined from the output voltage or output current of the fuel cell (hereinafter collectively referred to as “fuel cell output”). It focuses on the fact that it can be predicted. That is, in the fuel cell of the present invention, the alcohol concentration in the fuel is calculated from the fuel cell output and temperature, and based on this result, the fuel pump P1 and / or the water pump P4 is operated, and the alcohol concentration in the mixing tank 19 is determined. Control.

  FIG. 2 shows the relationship between alcohol concentration and fuel cell output voltage at each temperature, and FIG. 3 shows the relationship between fuel cell temperature and output voltage. From this figure, the alcohol concentration can be calculated from the temperature and the output voltage. For example, when the temperature is 60 ° C. and the output voltage is 14 V, the alcohol concentration can be estimated to be 3%. Therefore, when it is desired to maintain the alcohol concentration in the tank at, for example, 3%, the fuel cell control unit 52 causes the fuel pump P1 and / or the water pump of FIG. 1 so that the output voltage becomes 14 V under a constant temperature condition. P4 is operated to supply alcohol from the fuel tank. Further, FIG. 4 shows the relationship between the alcohol concentration and the fuel cell output current. A similar relationship is established between the two, and the alcohol concentration can be calculated from the temperature and the output current.

  Thus, in the fuel cell system of the present invention, the alcohol concentration can be calculated from the relationship between the fuel cell output and the temperature without installing an alcohol concentration sensor.

  Here, considering that the fuel cell is used as a drive source for an electronic device or the like, depending on the type of the electronic device, it may be assumed that an accurate alcohol concentration cannot be obtained from the fuel cell output. For example, in an electrophotographic image forming apparatus, a large amount of power is instantaneously consumed when heat is fixed on a fixing roller. In an ink jet image forming apparatus, the current increases rapidly when the carriage starts moving or when the recording medium starts to be fed. In such a case, the output on the fuel cell side fluctuates, which may make it difficult to accurately determine the methanol concentration.

  However, in the present invention, as shown below, even when the power consumption of an electronic device or the like driven by a fuel cell fluctuates greatly, the fuel cell output is kept constant and the alcohol concentration is accurately calculated. Can do.

  FIG. 5 shows the configuration of a fuel cell system that keeps the fuel cell output constant even when it is used as a power source for electronic equipment with a heavy load fluctuation. The fuel cell system is provided with a temperature sensor and a constant current device 54. The temperature sensor is attached to the fuel cell main body 3, and the temperature signal from the temperature sensor is input to the A / D input terminal of the fuel cell control unit 52. Since the output current of the fuel cell is taken out via the constant current device 54, even if the current consumed on the electronic device side changes significantly, the fuel cell output current is not affected by this, and as a result, the output voltage is It is a constant value determined by the stack temperature and alcohol concentration. Therefore, the alcohol concentration in the mixing tank 19 can be controlled by the method described above.

  Thus, in the fuel cell system of the present invention, the fuel cell output can be kept constant and the alcohol concentration can be accurately calculated regardless of the type of electronic equipment to be driven.

  Therefore, stable power supply from the fuel cell system is possible without installing an alcohol concentration sensor. Therefore, the fuel cell system can be reduced in size and weight, and the cost can be reduced.

Hereinafter, embodiments of the fuel cell system capable of exhibiting the above-described characteristic effects will be described.
(First embodiment)
FIG. 6 shows a first example of the fuel cell system 100. The fuel cell system 100 is connected to a control circuit 50 of an external device. A constant current device 54, a power storage device 53, and a DC-DC converter 51 are provided between the two. The constant current device 54 is installed on the most upstream side when viewed from the output side of the fuel cell 3, and the DC-DC converter 51 is installed in series with the constant current device 54 on the downstream side thereof. The power storage device 53 is installed in parallel with the fuel cell 3 so that the output current merges with the current from the constant current device 54 and is supplied to the DC-DC converter 51. However, the output current from the constant current device 54 side may flow in the direction of the power storage device 53 (during charging). The constant current device 54 plays a role of keeping the output current from the fuel cell 3 constant. For example, when the external device is an electronic device and a large current is required for the control circuit 50, a necessary amount of current is supplied from the power storage device 53. Thus, the constant current device 54 prevents the fuel cell from being affected by large power consumption fluctuations on the external device side. Therefore, the output voltage of the fuel cell 3 is kept constant, and the alcohol concentration in the mixing tank 19 can be calculated from the voltage value and the measured temperature by the above-described method. Then, the fuel cell control unit 52 operates the fuel pump P1 and / or the water pump P4 based on the obtained calculated value, and the alcohol concentration in the fuel tank is kept constant, so that the fuel cell 3 is always stable. It is possible to operate with output.

However, if the alcohol concentration is changed, it takes time for the change to appear as a change in the output voltage or output current.If replenishment is performed until the output voltage or output current changes, the replenishment amount will be exceeded. For example, it is necessary to devise such as calculating the alcohol concentration every minute and supplying 1 cc of alcohol when the alcohol concentration is low.
(Second embodiment)
A second embodiment is shown in FIG. In the first embodiment, a constant current device 54 is used to keep the output current of the fuel cell 3 constant. On the other hand, in this embodiment, the same effect is exhibited by the current sensor 55 installed on the most upstream side when viewed from the output side of the fuel cell 3, the power storage device 53, and the current control device 56 installed in series with the power storage device 53. Is done. Here, the positional relationship between the current sensor 55 and the power storage device 53 is the same as the positional relationship between the constant current device 54 and the power storage device 53 in the first embodiment. Specifically, the current sensor 55 transmits an output current signal from the fuel cell 3 to the current control device 56. The current control device 56 controls the charging current to the power storage device 53 based on the output current signal, thereby maintaining the output current of the fuel cell 3 constant. Therefore, as in the case of the first embodiment, the alcohol concentration in the mixing tank 19 can be calculated from the output voltage of the fuel cell 3 and the measured temperature.
(Third embodiment)
A third embodiment is shown in FIG. The basic structure of this embodiment is the same as that of the second embodiment, but a diode 57 is installed in parallel with the current control device 56. In this arrangement, the current from the power storage device 53 can be bypassed from the current control device 56 by the diode 57, and the resistance loss of the current by the voltage control circuit 56 can be reduced.
(Fourth embodiment)
A fourth embodiment is shown in FIG. The components of the fourth embodiment and their arrangement are the same as those of the second embodiment. However, in this example, the current control device 56 uses the output of the fuel cell as a voltage signal, and controls the charging current of the power storage device 53 so that the output voltage becomes constant. Thereby, the output voltage of the fuel cell 3 is maintained constant, and the alcohol concentration in the mixing tank 19 can be calculated from the relationship between the current signal from the current sensor 55 and the measured temperature.
(Fifth embodiment)
A fifth embodiment is shown in FIG. In this embodiment, a diode 57 is provided in parallel with the current control device 56 in the fourth embodiment. Thereby, the current from power storage device 53 can be bypassed from current control device 56, and the resistance loss of current by current control device 56 can be reduced.
(Sixth and seventh embodiments)
The operation of the constant current device 54 may be directly controlled by a control signal from the fuel cell control unit 52. For example, normally, the current is repeatedly turned on and off in the constant current device 54. However, at times other than the time of alcohol concentration calculation, the constant current device 54 is not operated in this way and is continuously energized. Also in this case, the power loss generated in the constant current device 54 can be significantly suppressed.

A sixth embodiment is shown in FIG. 11, and a seventh embodiment is shown in FIG. The sixth embodiment is a system in which the current control device 56 is operated only for a certain period in the third embodiment of FIG. Further, the seventh embodiment is a system in which the current control device 56 is operated for a certain period in the fifth embodiment of FIG. That is, when the alcohol concentration is not calculated, a control release signal is output from the fuel cell control unit, and the current control device 56 is short-circuited during that time. Thereby, the power loss which arises with the current control apparatus 56 can be suppressed significantly.
(Eighth embodiment)
An eighth embodiment is shown in FIG. This embodiment has almost the same configuration as the first embodiment. However, in this embodiment, a switch 60 is provided in parallel with the constant current device 54. Therefore, the current flowing through the constant current device 54 can be bypassed by a switching signal from the fuel cell control unit as necessary. For example, when the alcohol concentration is not calculated, a switching signal is output from the fuel cell control unit 52, and the constant current device 54 is bypassed during that time. Thereby, the power loss which arises with the constant current apparatus 54 can be suppressed significantly.

  The present invention is not limited to the above-described embodiments. In the present invention, any element may be used between the electronic device and the electronic device as long as the output on the fuel cell side is constant. It is necessary to keep in mind.

  Hereinafter, an aspect of an electronic apparatus including such a fuel cell system will be described.

  FIG. 14 is a schematic perspective view of an ink jet printer using the fuel cell system of the present invention as a power source. This ink jet printer is composed of a fuel cell system and a printer portion that operates by receiving power from the fuel cell system.

  Next, the internal structure of the printer portion will be described with reference to FIG. In FIG. 15, a line feed motor 201, a pressing member 202, a wire 203, an HP (position) sensor 204, a recording head cartridge 205, a carriage 206, a cable 207, a carriage motor 208, and a recording sheet 209 are shown. A platen roller 210 and a shaft 211 are shown.

  The recording head cartridge 205 is an integral unit of a recording head IJH and an ink tank as an ink supply source. The recording head cartridge 205 is fixed on the carriage 206 by a pressing member 202, and these can reciprocate in the longitudinal direction along the shaft 211.

  The ink droplets ejected from the recording head IJH reach the recording paper 209 whose recording surface is regulated by the platen roller 210 at a minute interval from the recording head IJH, and form an image. A recording timing pulse corresponding to image data is supplied to the recording head IJH from an appropriate data supply source via the cable 207 and a terminal coupled thereto.

  One to a plurality of recording head cartridges 205 (two in the illustrated example) can be provided depending on the ink color used. The carriage motor 208 is for causing the carriage 206 to scan along the shaft 211. The wire 203 is for transmitting the driving force of the motor 208 to the carriage 206. A line feed motor 201 is coupled to the platen roller 210 to convey the recording paper 209. The HP sensor 204 detects the position of the carriage 206.

  Next, the printer control circuit 50 and the fuel cell system 100 for executing the recording control of the ink jet printer according to the present embodiment will be described with reference to FIG.

  A fuel cell system 100 shown in FIG. 16 supplies electric power necessary for performing a recording operation of an ink jet printer, and is composed of a fuel cell and a DC-DC converter. The control circuit 50 corresponding to the control means includes a CPU 101, a ROM 102, a RAM 103, a data receiving unit 104, a DMA / RAM controller 105, a nonvolatile memory 106, a head driver 107, a head controller 108, The timing control unit 112, the line feed driver 113, the ink flow rate detection unit 114, the line feed motor 201, the carriage motor 208, and the recording head IJH are included.

  The CPU 101 is for executing operation control and data processing of the ink jet printer. The ROM 102 stores a control program for the CPU 101 and various data for font processing. The RAM 103 temporarily stores various data including received image data. The data receiving unit 104 is for capturing image data sent from an external device such as a host computer.

  The DMA / RAM controller 105 DMA-transfers image data received by the data receiving unit 104 to the RAM 103 and controls access from the CPU 101 to the RAM 103. The nonvolatile memory 106 stores parameters specific to the printer, such as an EEPROM. The head driver 107 drives the recording head IJH. The head controller 108 transfers image data to the head driver 107 and generates a heat pulse signal under the control of the CPU 101.

  The carriage motor driver 110, the carriage motor 208, and the timing control unit 112 are a control system that moves the recording head IJH by a control signal supplied from the CPU 101 and a recording timing pulse by an encoder or the like. The direction in which the recording head IJH moves is called the main scanning direction. The line feed motor driver 113 and the line feed motor 201 are control systems that convey a recording medium such as the recording paper 209 in accordance with a control signal supplied from the CPU 101. The direction in which this recording medium is conveyed is called the sub-scanning direction.

  The ink flow rate detection unit 114 counts the number of ink droplets (dots) ejected for recording within a predetermined time from the recording signal sent to the recording head IJH, and is supplied from the ink tank to the recording head IJH. It is a control circuit that detects the flow rate of ink.

  The basic recording control executed by the ink jet printer according to the present embodiment will be described with reference to FIG. 16 described above.

  First, image data input from the host computer by the data receiving unit 104 is temporarily stored in the RAM 103 via the DMA / RAM controller 105. The CPU 101 executes a control program stored in the ROM 102 and analyzes received commands, image data, and character codes. Thereafter, the input image data is converted into recording data by the CPU 101 and sequentially stored in the RAM 103. The reception command includes recording control information, and recording is performed with the number of recording passes corresponding to the recording control information.

  The carriage motor 208 is driven by the carriage motor driver 110 when the development of the recording data for one line is completed or when a recording command as one of received commands is input from the host computer. The recording data stored in the RAM 103 is transferred to the head driver 107 via the DMA / RAM controller 105 and the head controller 108 in synchronization with the recording timing pulse output from the timing control unit 112. Then, a heat pulse signal is sent from the head controller 108 to the head driver 107, and ink droplets are ejected from the recording head IJH.

  When the recording for one line is completed, the line feed motor 201 is driven to perform a line feed, and a series of procedures is completed. By repeating such a procedure over one page of the recording paper 209, the recording operation for one page is completed.

  As long as the discharge amount that can be generated is not exceeded by the above control, printing is performed in a printing mode with a small number of scans, and there is an effect that a substantial printing speed is increased.

  In the above example, an inkjet printer is used as the electronic device. However, the electronic device may be an electrophotographic image forming apparatus or other electronic device.

  As described above, in the present invention, the fuel alcohol concentration is predicted from the output voltage or output current of the fuel cell main body and the temperature. Therefore, the fuel cell system according to the present invention can perform stable output without installing an expensive alcohol concentration sensor. In addition, since the system is configured so that the output from the fuel cell side is constant, this fuel cell system is the same even if it is used as a power supply source (power supply unit) for a device with a heavy load fluctuation such as a printer. Stable output is possible. Accordingly, the fuel cell system can be reduced in size and weight, and the cost can be further reduced.

  The present invention can be used for all electronic devices having a fuel cell using alcohol as a fuel.

It is a figure which shows the general structure of a fuel cell. It is a figure which shows the relationship between the alcohol concentration in each temperature, and a fuel cell output voltage. It is a figure which shows the relationship between fuel cell temperature and an output voltage. It is a figure which shows the relationship between the alcohol concentration and fuel cell output current in each temperature. It is a figure which shows the example of control operation of a fuel cell. It is a figure which shows the relationship between the fuel cell system of this invention, and an external apparatus control circuit. It is a figure which shows the 2nd relationship between the fuel cell system of this invention, and an external apparatus control circuit. It is a figure which shows the 3rd relationship between the fuel cell system of this invention, and an external apparatus control circuit. It is a figure which shows the 4th relationship between the fuel cell system of this invention, and an external apparatus control circuit. It is a figure which shows the 5th relationship between the fuel cell system of this invention, and an external apparatus control circuit. It is a figure which shows the 6th relationship between the fuel cell system of this invention, and an external apparatus control circuit. It is a figure which shows the 7th relationship between the fuel cell system of this invention, and an external apparatus control circuit. It is a figure which shows the 8th relationship between the fuel cell system of this invention, and an external apparatus control circuit. It is a general-view perspective view of an inkjet printer. It is an internal structure figure of a printer part. It is a figure which shows the control circuit of an inkjet printer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Fuel cell 5 Fuel cell main body 7 Anode 9 Cathode 17 Fuel tank 19 Mixing tank 20 Water tank 27 Fuel supply path 31 Condenser 35 Fan 37 Cooling air 50 Electronic equipment control circuit 51 DC-DC converter 52 Fuel cell control part 53 Power storage device 54 constant current device 56 current control device 57 diode 60 switch 100 fuel cell system 101 CPU
102 ROM
103 RAM
104 Data receiver 105 RAM / DMA controller 106 Non-volatile memory 107 Head driver 108 Head controller 110 Carriage motor driver 112 Timing controller 113 Line feed driver 114 Ink flow detector IJH recording head P1 Fuel pump P2 Circulation pump P3 Blower P4 Water pump .

Claims (14)

A fuel cell main body, a storage tank for alcohol as a fuel source, a mixing tank connected to the storage tank via a fuel pump and supplying fuel containing alcohol and water to the fuel cell main body, and operation of the fuel pump A fuel cell system having control means for controlling the fuel cell output by controlling
The control means controls the operation of the fuel pump based on the temperature of the fuel cell main body and the output voltage or output current. A fuel cell main body, a storage tank for alcohol as a fuel source, a mixing tank connected to the storage tank via a fuel pump and supplying fuel containing alcohol and water to the fuel cell main body, and operation of the fuel pump A fuel cell system for controlling the fuel cell output and controlling the fuel cell output, connected to a control circuit of an external device, and driving the external device,
The fuel cell system has circuit means for maintaining a constant output current from the fuel cell body regardless of load fluctuations of the external device,
The control means controls the operation of the fuel pump based on the temperature and output voltage of the fuel cell main body. A fuel cell main body, a storage tank for alcohol as a fuel source, a mixing tank connected to the storage tank via a fuel pump and supplying fuel containing alcohol and water to the fuel cell main body, and operation of the fuel pump A fuel cell system for controlling the fuel cell output and controlling the fuel cell output, connected to a control circuit of an external device, and driving the external device,
The fuel cell system has circuit means for maintaining a constant output voltage from the fuel cell body regardless of load fluctuations of the external device,
The control means controls the operation of the fuel pump based on the temperature and output current of the fuel cell main body.   The circuit means for maintaining the output current constant is composed of a constant current device and a power storage device, and the constant current device is in the most upstream side when viewed from the output side of the fuel cell body, and in series with the control circuit of the external device. The power storage device is connected to the fuel cell main body so that the current supplied from the fuel cell side via the constant current device and the current from the power storage device merge and are supplied to the control circuit of the external device. The fuel cell system according to claim 2, wherein the fuel cell system is connected in parallel.   The circuit means for maintaining the output current constant is composed of a current sensor, a power storage device and a current control device, and the current sensor is connected to the control circuit of the external device on the most upstream side when viewed from the output side of the fuel cell body. The power storage device is connected in series, and the current supplied from the fuel cell side via the current sensor and the current from the power storage device merge to be supplied to the control circuit of the external device in parallel with the fuel cell main body. The connected current control device is connected in series with the power storage device upstream of the power storage device as viewed from the fuel cell output side, and controls the charge / discharge amount of the power storage device according to the current signal from the current sensor. The fuel cell system according to claim 2.   The fuel cell system according to claim 5, further comprising a diode that bypasses a discharge current from the power storage device from the current control device.   The circuit means for maintaining the output voltage constant is composed of a current sensor, a power storage device, and a current control device, and the current sensor is connected to the control circuit of the external device on the most upstream side when viewed from the output side of the fuel cell body. The power storage device is connected in series, and the current supplied from the fuel cell side via the current sensor and the current from the power storage device merge to be supplied to the control circuit of the external device in parallel with the fuel cell main body. The connected current control device is connected in series with the power storage device upstream of the power storage device as viewed from the fuel cell output side, and controls the charge / discharge amount of the power storage device according to the output voltage of the fuel cell main body. The fuel cell system according to claim 3.   The fuel cell system according to claim 7, further comprising a diode that bypasses a discharge current from the power storage device from the current control device.   The fuel cell system according to claim 6 or 8, wherein the control means short-circuits the current control device at a predetermined time interval.   A switch circuit connected in parallel with the constant current device, wherein the control means closes the switch circuit at a predetermined time interval, and switches a current flow from the fuel cell body on the constant current device and the switch circuit side. The fuel cell system according to claim 4, wherein   The fuel cell system according to claim 4, wherein the control unit short-circuits the constant current device at a predetermined time interval.   The fuel cell system according to claim 4, wherein the power storage device is a secondary battery.   An electronic device comprising the fuel cell system according to any one of the preceding claims.   An image forming apparatus comprising the fuel cell system according to claim 1.

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