JP2009208253A - Electric power supply controlling apparatus, recording apparatus, and electric power supply controlling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power supply controlling apparatus, a recording apparatus, and an electric power supply controlling method, detecting short-circuiting (failure) of a loading at a high speed and controlling electric power supply to the load. <P>SOLUTION: The electric power supply controlling apparatus is equipped with: a capacitor connected in parallel to the load supplying the electric power through an electric power supply wiring; and a detecting circuit connected in parallel with the load to detect an electric voltage to the load and to output it. The apparatus is equipped with a switching element connected to the electric power supply wiring, and performing on/off according to an inputted control signal. Then, by using such an apparatus as this, the electric voltage outputted from the detecting circuit is compared with the electric voltage of the threshold value, and according to the result of the comparison, an on/off control of the switching element is performed from the control signal to control electric power supply to the load. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply control device, a recording device, and a power supply control method. In particular, the present invention relates to a power control supply apparatus, for example, a recording apparatus that performs recording using a recording head whose power supply is controlled using the power control supply apparatus, and a power supply control method.

  There have been many attempts to reduce the power consumption of electronic devices.

  For example, in a state where the recording apparatus (printer) is not performing a recording operation, power supply to a part of the recording head and the control circuit of the recording apparatus is stopped.

  FIG. 8 is a circuit diagram showing a configuration of a conventional power supply circuit.

  Here, for example, the recording head 3 is assumed as the load.

  According to this configuration, the voltage Vin is input to the power supply circuit, and the voltage Vh is supplied to the recording head 3. The line through which the current I flows is called a power supply line.

  This power supply circuit includes a capacitor 103 connected in parallel with the recording head 3 and an FET 101 which is a switching element for controlling the voltage Vh supplied to the recording head 3 and the capacitor 103. Further, it includes a transistor 102 that is a switching element that inputs a control signal C to control on / off of the FET 101, a resistor 105 that divides the control voltage of the FET 101, and a resistor 106. Here, it is assumed that the recording head 3 as a load has two states of an operation state and a non-operation state, and is open in terms of a circuit when not in operation.

  When the FET 101 is turned on, a voltage Vin supplied from a power supply (for example, an AC / DC power supply circuit) is applied to the recording head 3. At this time, if the recording head 3 is in a non-operating state, the recording head 3 is open and no current flows through the recording head 3. On the other hand, since a current flows into the capacitor 103 connected in parallel with the recording head 3, a current I flows through the FET 101.

  Here, when the FET 101 is turned on when the power of the recording apparatus is turned on in a state where the difference between the voltage Vin and the voltage Vh is large (when the power of the recording apparatus is off), the power consumed by the FET 101 is large. Thus, the FET 101 may fail.

For this purpose, PWM control is performed by a control signal (first control signal) C when the FET 101 is turned on to control the current I. Charge is stored in the capacitor 103 by this controlled current, and the difference between the voltage Vin and the voltage Vh is reduced. Then, when the difference between the voltage Vin and the voltage Vh becomes sufficiently small, the FET 101 is turned on, thereby suppressing the power consumed by the FET 101 and reducing heat generation.
JP-A-7-143759

  However, in the above conventional example, when the recording head 3 as a load fails, the FET 101 may fail. This is because, even when a current limited by the PWM control is supplied when the recording head 3 fails, the current flows through the recording head 3, so that no charge can be stored in the capacitor 103. In other words, even if PWM control is performed, the difference between the voltage Vin and the voltage h is not reduced. For this reason, the FET 101 is kept on for a long time with a large difference between the voltage Vin and the voltage Vh. As a result, a failure occurs in the FET 101.

  As described above, when the FET 101 fails, the input voltage Vin is continuously supplied to the recording head 3 in the failed state.

  Until now, for example, in order to detect a short circuit of a load (here, an inverter circuit), when driving the load, there is a technique of detecting and driving the short circuit of the load (for example, see Patent Document 1). ). However, this conventional technique has a problem that it takes time to detect a short circuit. Further, it is impossible to prevent a failure of a switching element such as the FET 101 of the power supply circuit.

  The present invention has been made in view of the above conventional example, and provides a power supply control device, a recording device, and a power supply control method that can detect a short circuit (failure) of a load at high speed and control power supply to the load. The purpose is to do.

  In order to achieve the above object, the power supply control device of the present invention has the following configuration.

  That is, a capacitor that is connected in parallel to a load that supplies power via a power supply line that is a first current path, and a capacitor that is connected in parallel to the load, and detects a voltage to the load. An output circuit; and a first switching element connected to the power supply line and turned on / off according to the input first control signal; and power to the load according to on / off of the first switching element The supply is controlled.

  According to another aspect of the invention, there is provided a recording apparatus that operates by being supplied with electric power through the electric power supply control apparatus having the above-described configuration, and compares the voltage output from the circuit with a threshold voltage. A recording apparatus comprising: control means for controlling on / off of the first switching element by the first control signal according to a result of comparison by the comparison means, and for controlling power supply to the load. .

  According to still another invention, there is provided a power supply control method using the power supply control device configured as described above, wherein a comparison step of comparing a voltage output from the circuit with a threshold voltage, and a comparison in the comparison step And a control step of controlling power supply to the load by controlling on / off of the first switching element by the first control signal according to the result.

  Therefore, according to the present invention, since the voltage to the load is directly detected from the power supplied to the load and the abnormality of the load is detected, the power supply to the load can be controlled at high speed.

  Further, for example, when a load is detected, current supply bypassing the switching element that turns on and off the power supply to the load is performed, so that the switching element can be protected.

  Hereinafter, preferred embodiments of the present invention will be described more specifically and in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the already demonstrated part and duplication description is abbreviate | omitted.

  In this specification, “recording” (sometimes referred to as “printing”) is not limited to the case of forming significant information such as characters and graphics, but may be significant. It also represents the case where an image, a pattern, a pattern, etc. are widely formed on a recording medium, or the medium is processed, regardless of whether it is manifested so that humans can perceive it visually. .

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  Further, “ink” (sometimes referred to as “liquid”) should be interpreted widely as in the definition of “recording (printing)”. Therefore, by being applied on the recording medium, it is used for formation of images, patterns, patterns, etc., processing of the recording medium, or ink processing (for example, solidification or insolubilization of the colorant in the ink applied to the recording medium). It shall represent a liquid that can be made.

  Furthermore, unless otherwise specified, the “recording element” collectively refers to an ejection port or a liquid path communicating with the ejection port and an element that generates energy used for ink ejection.

<Description of Inkjet Recording Apparatus (FIG. 1)>
FIG. 1 is an external perspective view showing an outline of the configuration of an ink jet recording apparatus 1 which is a typical embodiment of the present invention.

  As shown in FIG. 1, an ink jet recording apparatus (hereinafter referred to as a recording apparatus) has a recording head 3 mounted on a carriage 2 for performing recording by discharging ink according to an ink jet system. A driving force generated by the carriage motor M1 is transmitted to the carriage 2 from the transmission mechanism 4, and the carriage 2 is reciprocated in the arrow A direction. At the time of recording, for example, a recording medium P such as recording paper is fed through the paper feeding mechanism 5 and conveyed to a recording position, and recording is performed by ejecting ink from the recording head 3 to the recording medium P at the recording position. Do.

  Further, in order to maintain the state of the recording head 3 satisfactorily, the carriage 2 is moved to the position of the recovery device 10 and the ejection recovery process of the recording head 3 is intermittently performed.

  In addition to mounting the recording head 3 on the carriage 2 of the recording apparatus 1, an ink cartridge 6 for storing ink to be supplied to the recording head 3 is mounted. The ink cartridge 6 is detachable from the carriage 2.

  The recording apparatus 1 shown in FIG. 1 is capable of color recording. For this reason, the carriage 2 contains four inks containing magenta (M), cyan (C), yellow (Y), and black (K) inks, respectively. An ink cartridge is installed. These four ink cartridges are detachable independently.

  Now, the carriage 2 and the recording head 3 can achieve and maintain a required electrical connection by properly contacting the joint surfaces of both members. The recording head 3 applies energy according to a recording signal to selectively eject ink from a plurality of ejection ports for recording. In particular, the recording head 3 of this embodiment employs an ink jet system that ejects ink using thermal energy. For this reason, the recording head 3 is provided with an electrothermal transducer for generating thermal energy. The electrical energy applied to the electrothermal converter is converted to thermal energy, and the ink is ejected from the discharge port using the pressure change caused by the growth and contraction of bubbles caused by film boiling caused by applying the thermal energy to the ink. To discharge. The electrothermal transducer is provided corresponding to each of the ejection ports, and ink is ejected from the corresponding ejection port by applying a pulse voltage to the corresponding electrothermal transducer in accordance with the recording signal.

  As shown in FIG. 1, the carriage 2 is connected to a part of the driving belt 7 of the transmission mechanism 4 that transmits the driving force of the carriage motor M <b> 1, and slides in the direction of arrow A along the guide shaft 13. It is guided and supported freely. Accordingly, the carriage 2 reciprocates along the guide shaft 13 by forward and reverse rotations of the carriage motor M1. A scale 8 is provided for indicating the absolute position of the carriage 2 along the moving direction of the carriage 2 (arrow A direction, scanning direction). In this embodiment, the scale 8 uses a transparent PET film on which black bars are printed at the necessary pitch, one of which is fixed to the chassis 9 and the other is supported by a leaf spring (not shown). Yes.

  Further, the recording apparatus 1 is provided with a platen (not shown) facing the discharge port surface where the discharge port (not shown) of the recording head 3 is formed. Then, the carriage 2 on which the recording head 3 is mounted is reciprocated by the driving force of the carriage motor M1, and at the same time, a recording signal is given to the recording head 3 to eject ink, thereby conveying the recording medium P conveyed onto the platen. Recording is performed over the full width.

  Further, in FIG. 1, reference numeral 14 denotes a conveyance roller driven by a conveyance motor M2 to convey the recording medium P, and 15 denotes a pinch roller that abuts the recording medium P against the conveyance roller 14 by a spring (not shown). Reference numeral 16 denotes a pinch roller holder that rotatably supports the pinch roller 15, and reference numeral 17 denotes a conveyance roller gear fixed to one end of the conveyance roller 14. Then, the transport roller 14 is driven by the rotation of the transport motor M2 transmitted to the transport roller gear 17 through an intermediate gear (not shown).

  Further, reference numeral 20 denotes a discharge roller for discharging the recording medium P on which an image is formed by the recording head 3 to the outside of the recording apparatus, and is driven by transmitting the rotation of the transport motor M2. . The discharge roller 20 abuts on a spur roller (not shown) that presses the recording medium P by a spring (not shown). Reference numeral 22 denotes a spur holder that rotatably supports the spur roller.

  Furthermore, the recording apparatus 1 includes a recording head at a desired position (for example, a position corresponding to the home position) outside the range of reciprocal motion for recording operation of the carriage 2 on which the recording head 3 is mounted (outside the recording area). A recovery device 10 for recovering the ejection failure 3 is provided.

  The recovery device 10 includes a capping mechanism 11 for capping the ejection port surface of the recording head 3 and a wiping mechanism 12 for cleaning the ejection port surface of the recording head 3. In conjunction with capping of the ejection port surface by the capping mechanism 11, ink is forcibly discharged from the ejection port by a suction means (suction pump or the like) in the recovery device, and the viscosity in the ink flow path of the recording head 3 is increased. The ejection recovery process such as removing the ink and bubbles is performed.

  Further, when the recording head 3 is not in operation or the like, the ejection port surface of the recording head 3 is capped by the capping mechanism 11 to protect the recording head 3 and to prevent ink evaporation and drying. On the other hand, the wiping mechanism 12 is disposed in the vicinity of the capping mechanism 11 and wipes ink droplets adhering to the ejection port surface of the recording head 3.

  The capping mechanism 11 and the wiping mechanism 12 can keep the ink ejection state of the recording head 3 normal.

<Control Configuration of Inkjet Recording Apparatus (FIG. 2)>
FIG. 2 is a block diagram showing a control configuration of the recording apparatus shown in FIG.

  As shown in FIG. 2, the controller 600 includes an MPU 601, a ROM 602, a special purpose integrated circuit (ASIC) 603, a RAM 604, a system bus 605, an A / D converter 606, and the like. Here, the ROM 602 stores a program corresponding to a control sequence to be described later, a required table, and other fixed data. The ASIC 603 generates control signals for controlling the carriage motor M1, the transport motor M2, and the recording head 3. The RAM 604 is used as a development area for image data, a work area for program execution, and the like. A system bus 605 connects the MPU 601, the ASIC 603, and the RAM 604 to each other to exchange data. The A / D converter 606 inputs analog signals from the sensor group described below, performs A / D conversion, and supplies a digital signal to the MPU 601.

  In FIG. 2, reference numeral 610 denotes a computer (or an image reading reader, digital camera, or the like) serving as a supply source of image data, and is collectively referred to as a host device. Image data, commands, status signals, and the like are transmitted and received between the host apparatus 610 and the recording apparatus 1 via an interface (I / F) 611. This image data is input in a raster format, for example.

  Reference numeral 620 denotes a switch group, which includes a power switch 621, a print switch 622, a recovery switch 623, and the like.

  Reference numeral 630 denotes a sensor group for detecting the apparatus state, and includes a position sensor 631, a temperature sensor 632, and the like.

  Further, 640 is a carriage motor driver that drives a carriage motor M1 for reciprocating scanning of the carriage 2 in the direction of arrow A, and 642 is a conveyance motor driver that drives a conveyance motor M2 for conveying the recording medium P.

  The ASIC 603 transfers drive data (DATA) of the printing element (ejection heater) to the printing head while directly accessing the storage area of the RAM 604 during printing scanning by the printing head 3.

  In addition, power is supplied to each unit of the recording apparatus 1 via the power supply unit 650.

  The power supply unit 650 includes an AC / DC conversion circuit 652 and a power supply circuit (protection circuit) 653. Details of the power supply circuit 653 will be described later.

  The AC / DC conversion circuit 652 converts an AC voltage of 100 VAC input from the outside through the plug 651 into a DC voltage of 24 VDC. The AC / DC conversion circuit 652 includes a feedback circuit for stabilizing the output voltage (Vin) at a certain level.

The controller 600 outputs a control signal C to the power supply circuit 653 and operates by inputting the voltage V ₀ from the power supply circuit 653. The power supply circuit 653 supplies a voltage Vh to the recording head 3.

  The configuration shown in FIG. 1 is a configuration in which the ink cartridge 6 and the recording head 3 can be separated, but a replaceable head cartridge may be configured by integrally forming them.

  Next, several embodiments of the power supply circuit used in the recording apparatus having the above configuration will be described.

  FIG. 3 is a circuit diagram showing a configuration of the power supply circuit 653 according to the first embodiment.

  In FIG. 3, the same components as those in the conventional circuit already described with reference to FIG. 8 are denoted by the same reference numerals, and the description thereof is omitted. Here, the characteristic configuration and operation of this embodiment are described. Will be described.

In this circuit configuration, a resistor 111 (first resistor) and a resistor 112 (second resistor) having sufficiently large resistance values are connected in parallel with the recording head 3 as a load for voltage detection. A voltage V ₀ which is a divided voltage generated by these resistors is output to the controller 600 as voltage information of the voltage Vh applied to the recording head.

The magnitude of the voltage V ₀ can be determined by the ratio of the resistor 111 and the resistor 112 and is controlled by the control signal C of the transistor 102.

  FIG. 4 is a signal time chart for explaining the operation of the power supply circuit 653.

  Hereinafter, the operation of the power supply circuit 653 will be described with reference to FIG. This operation is performed, for example, when the recording apparatus is powered on and when power supply to the recording head is resumed.

4A illustrates the change in the voltage V ₀ and the operation of the FET 101 during normal operation, and FIG. 4B illustrates the operation of the FET 101 during failure. In FIG. 4, Vth is a threshold voltage used for the failure determination described below.

The power supply circuit 653 can detect the voltage V ₀ at a predetermined timing in the PWM control period, thereby detecting a failure (short circuit) of the recording head 3.

For example, in FIG. 3A, the MPU 601 starts the first PWM control at time t = t ₀ . Then, the voltage V ₀ is detected at time t = t ₁ when a predetermined time has elapsed. This value is determined by the MPU 601 of the controller 600. After time t = t _1, it starts the second PWM control. At time t = t ₂ , the control signal C is output based on the determination result of the MPU 601. If normal, the FET 101 is turned on. Note that, as shown in FIG. 3B, the FET 101 is turned off at the time of failure.

More specifically, if V ₀ > Vth, it is determined that the recording head 3 as a load is in a normal state, and the FET 101 is turned on. On the other hand, if V ₀ ≦ Vth, it is determined that the recording head 3 as a load is in a failure state, and the FET 101 (first switching element) is turned off.

Here, by changing the PWM control based on the detection result of the voltage V ₀ , the FET 101 can be protected when the recording head 3 as a load is short-circuited. Thereby, the FET 101 is not turned on when the recording head 3 is short-circuited (failed), and the FET 101 can be protected when the recording head 3 is short-circuited (failed).

  FIG. 5 is a flowchart showing a procedure for controlling power supply to the recording head 3 as a load.

  First, in step S1, the first PWM control is started. The PWM value (duty value) of the first PWM control is a predetermined value.

In step S2, PWM control is performed for a period required to raise the voltage Vh to a desired voltage level (for example, 24 volts) in a normal state. In step S3, a second PWM control period for protecting the FET 101 is started while the voltage V ₀ is detected.

Then, to detect the voltage V ₀ at step S4. Further, the voltage V ₀ at step S5 it is checked whether the larger voltage (Vth) of the threshold. If V ₀ > Vth, the process proceeds to step S6. If V ₀ ≦ Vth, the process proceeds to S8.

  In step S6, it is determined that the print head as a load is operating normally, the second PWM control is terminated, and in step S7, the FET 101 is kept on. Note that the duty value of the second PWM control is lower than the duty value of the first PWM control.

  On the other hand, in step S8, the second PWM control is terminated, and in step S9, the FET 101 is turned off.

Further, the short circuit fault of the FET 101 can be detected by the voltage detection configuration provided in the voltage supply circuit according to this embodiment. The voltage Vin is always applied to the recording head 3 at the time of a short circuit failure of the FET 101 due to some cause, and the voltage V ₀ becomes larger than the threshold voltage (Vth) even when the FET 101 should be off. Therefore, by detecting the voltage V ₀ when the FET 101 is off, it is possible to detect a short-circuit failure of the FET 101.

  Further, when a short circuit failure of the FET 101 is detected, an error process such as turning off the voltage Vin by the MPU 601 can be performed to protect the recording head that is a load even when the short circuit failure of the FET 101 occurs.

Therefore, according to the embodiment described above, two resistors having sufficiently large resistance values are connected in parallel with the recording head 3 which is a load, and a voltage V ₀ which is a divided voltage generated by these resistors is applied to the recording head. Output as voltage information. As a result, the voltage V ₀ is output at a predetermined timing, and the failure of the recording head can be detected by comparing this with the threshold voltage.

Further, it is possible to detect a failure of the FET, which is a switching element constituting the power supply circuit, from the voltage V ₀ . In this way, the switching element can be protected even when a failure occurs in the recording head.

  FIG. 6 is a circuit diagram showing a configuration of a power supply circuit according to the second embodiment.

  In FIG. 6, the same reference numerals are given to the components shown in FIG. 4 which is the first embodiment and the components shown in FIG. 8 which is the conventional example, and the description thereof will be omitted. A characteristic configuration and operation will be described.

  In the configuration according to the second embodiment, the controller 600 outputs the control signals C and C2 to the power supply circuit 653.

In Example 1, the current path from the point A to the recording head 3 as a load was only the current path (first current path: I ₁ ) flowing from the point A through the FET 101 to the point B. In this embodiment, a current path (second current path: I ₂ ) returning from the point A to the point B via the FET 114 (second switching element) is newly provided. That is, when the FET 101 is in an off state, power is supplied to the recording head 3 via the second current path. The second current path is provided with a resistor 120 having a sufficiently large resistance value, and is controlled by turning on / off the FET 114. The FET 114 is turned on / off by a control signal (second control signal) C2. Therefore, the current supplied by the second current path is small.

  In FIG. 6, 116 and 117 are resistors, and 115 is a transistor as a switching element.

In the power supply circuit of this embodiment, when power supply to the recording head 3 as a load is started, the FET 114 is turned on and power is supplied to the recording head 3 via the resistor 120. Since the current is controlled by the resistor 120 in the second current path, even if the difference between the voltage Vin and the voltage Vh is large, the power consumed by the FET 114 is small. After the FET 114 is turned on, the electric charge is stored in the capacitor 103, and the voltage V ₀ is detected after a period when the voltage V 0 becomes sufficiently large. By this detection, it is possible to detect a short circuit (failure) of the recording head 3 as a load.

Here, if the voltage V ₀ is larger than the threshold voltage (Vth), it can be determined that the recording head 3 is in a normal state, the FET 101 is turned on, the FET 114 is turned off, and a current path is routed to a path having a small resistance value. Switch. On the other hand, if V ₀ ≦ Vth (that is, the threshold voltage or less), it is determined that the recording head 3 is in a short circuit (failure) state. And FET101 is protected by turning off FET114, without turning on FET101.

  FIG. 7 is a flowchart showing a procedure for supplying power to the recording head 3 as a load.

  In this case, the FET 101 is first turned off by the control signal C.

First, after turning on the FET 114 in step S11, in step S12, the process waits for a predetermined time and waits for processing. Then, in step S13, it detects the voltage V _0.

In step S14, it compares the voltage V ₀ and the threshold voltage (Vth). If V ₀ > Vth, the process proceeds to step S15, and if V ₀ ≦ Vth, the process proceeds to step S17.

  In step S15, the FET 101 is turned on, and in step S16, the FET 114 is turned off. As a result, the power supply path is changed from the second current path to the first current path. The same power supply as in the first embodiment is performed.

  In step S17, the FET 114 is turned off and the power supply to the recording head 3 is stopped.

  Therefore, according to the embodiment described above, two current paths are provided, and when a short circuit (fault) state of the print head is detected, a current supply bypassing the FET 101 is supplied to detect a short circuit (fault) state of the print head. Therefore, the load on the FET 101 can be reduced.

  In the above embodiments, the liquid droplets ejected from the recording head have been described as ink, and the liquid stored in the ink tank has been described as ink. However, the storage is limited to ink. It is not a thing. For example, a treatment liquid discharged to the recording medium may be accommodated in the ink tank in order to improve the fixability and water resistance of the recorded image or to improve the image quality.

  The above embodiment uses a method that includes means (for example, an electrothermal converter) for generating thermal energy for ink ejection, and causes a change in the state of the ink by the thermal energy, among ink jet recording methods. High density and high definition of recording can be achieved.

  In addition, as an embodiment of the ink jet recording apparatus of the present invention, in addition to those used as an image output apparatus of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and further a facsimile apparatus having a transmission / reception function. It may be one taken.

1 is an external perspective view showing an outline of a configuration of an ink jet recording apparatus that is a representative embodiment of the present invention. 3 is a block diagram illustrating a configuration of a control circuit of the recording apparatus. FIG. 1 is a circuit diagram showing a configuration of a power supply circuit according to Embodiment 1. FIG. 3 is a signal time chart according to the first embodiment. 4 is a flowchart illustrating a procedure for supplying power to the recording head 3 according to the first embodiment. FIG. 6 is a circuit diagram showing a configuration of a power supply circuit according to a second embodiment. 6 is a flowchart illustrating a procedure for supplying power to a recording head 3 according to a second embodiment. It is a circuit diagram of the conventional power supply circuit.

Explanation of symbols

3 Recording head 101, 114 FET
103 Capacitors 111, 112 Resistor 653 Power supply circuit

Claims (10)

A capacitor connected in parallel to a load that supplies power via a power supply line that is a first current path;
A circuit connected in parallel to the load for detecting and outputting a voltage to the load;
A first switching element connected to the power supply line and turned on / off according to a first control signal inputted thereto;
The power supply control device, wherein power supply to the load is controlled according to on / off of the first switching element. A second current path that bypasses the first switching element and supplies power to the load;
A second switching element connected to the second current path and turned on / off in accordance with an input second control signal;
2. The power supply to the load is controlled according to ON / OFF of the second switching element when power is supplied to the load through the second current path. The power supply control device described.   The power supply control device according to claim 1, wherein the first switching element and the second switching element are FETs. A plug for supplying an AC voltage from the outside;
An AC / DC conversion circuit that converts an AC voltage supplied through the plug into a DC voltage;
4. The voltage according to claim 1, wherein a predetermined voltage is supplied from the AC / DC conversion circuit to the first current path or the second current path. 5. Power supply control device. A recording apparatus that operates by being supplied with power via the power supply control apparatus according to any one of claims 1 to 4,
Comparing means for comparing the voltage output from the circuit with a threshold voltage;
A recording apparatus comprising: control means for controlling on / off of the first switching element by the first control signal according to a result of comparison by the comparison means, and for controlling power supply to the load.   The recording apparatus according to claim 5, wherein the control unit further controls to drive the first switching element by PWM control to supply power to the load.   The control means further checks the short circuit of the load by turning on the second switching element by the second control signal and supplying power to the load through the second current path. The recording apparatus according to claim 5, wherein the recording apparatus is controlled.   The recording apparatus according to claim 5, wherein the load is a recording head.   The control means determines that the recording head is in a normal state when the voltage output from the circuit is larger than the threshold voltage, and the voltage output from the circuit is equal to or lower than the threshold voltage. The recording apparatus according to claim 8, wherein the recording head is determined to be in a failure state. A power supply control method using the power supply control device according to any one of claims 1 to 4,
A comparison step of comparing the voltage output from the circuit with a threshold voltage;
And a control step of controlling on / off of the first switching element by the first control signal and controlling power supply to the load according to a result of the comparison in the comparison step. Supply method.

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