JP6576103B2 - Power supply device, printer, and control method - Google Patents

Description

  The present invention relates to a power supply device, a printer, and a control method, and more particularly, to a power supply device, a printer, and a control method including a unit that controls power supply to a load.

  In recent inkjet recording apparatuses (hereinafter also referred to as recording apparatuses), the number of nozzles for ejecting ink has been increasing in order to improve printing speed and print resolution. For example, in the case of a thermal recording apparatus, a heater is provided in the vicinity of the ink discharge port, and by supplying power to the heater, the ink is instantly foamed and the ink is ejected by the kinetic energy of the foaming.

  In such a recording apparatus, the power consumed at the time of image formation varies depending on the density of the image. When an image having a high density is formed, a large number of nozzle driving heaters are instantaneously turned on in order to eject a large amount of ink onto the paper surface, and a large current is passed through a head including the nozzles in a short time.

  When an instantaneous large current is passed, it is necessary to lower the impedance of the power supply, and a printer is known in which an electrolytic capacitor having a small equivalent series resistance value and a large capacity is connected to a power supply line near the recording head ( Patent Document 1). By supplying a large amount of electric charge accumulated in the electrolytic capacitor as instantaneous power, a drop in the heater driving voltage can be prevented and stable ink ejection can be realized.

JP 2009-286096 A

  In Patent Document 1, in an off state or a standby state, no power supply voltage is applied and no power is supplied to the head. Then, the head failure is confirmed in the off state or the standby state. For this reason, it is necessary to perform the heating operation again before starting the next printing operation.

  Therefore, in view of the above-described circumstances, the present invention provides a power supply device, a printer, and a control method that can appropriately detect the occurrence of an abnormality in a power supply circuit or a load and can speed up the start of the operation of the power load. This is the issue.

In order to achieve the above object, a power supply apparatus according to the present invention supplies power to a power load capable of moving in a first direction and moving in a second direction opposite to the first direction. A power supply for supplying power to the power load via a power supply line during operation of the power load; a capacitor connected to the power supply line for connecting the power supply and the power load; A specifying means for specifying a time elapsed since the start of power supply to the power load via the power supply line; and movement of the power load in the first direction and movement in the second direction. Determination means for determining whether the movement between the detection means, a detection means for detecting the voltage value of the capacitor, and an execution means for executing error processing based on the voltage value detected by the detection means, detection means, said-format Is determined to be between the moved by means, and wherein when a time specified by the specifying means has passed the predetermined time, detecting a voltage value of the capacitor in a state of stopping the power supply through the power supply line Even if it is determined that the movement is between the movements by the determination means, if the time specified by the specification means has not passed the predetermined time, the detection process is not executed.

  According to the present invention, it is possible to appropriately detect the occurrence of an abnormality in the power supply circuit or the load, and to accelerate the start of the operation of the power load.

FIG. 2 is a block diagram illustrating a control circuit configuration of the printer according to the first embodiment. It is a flowchart which shows the power supply control of a head. It is a timing chart which shows power supply control of a head. It is a flowchart which shows charge control of an electrolytic capacitor. It is a timing chart which shows charge and discharge to an electrolytic capacitor.

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

(Embodiment 1)
FIG. 1 is a block diagram illustrating a main configuration of a printer control circuit which is an example of a power supply apparatus according to the first embodiment. In FIG. 1, a printer having a printing function will be described as an example. However, the printer is not limited to this, and may be, for example, a composite printer having a printing function and a reading function.

  The printer shown in FIG. 1 includes a power supply circuit 101, a head power supply control block 102, a printer control CPU 123, a RAM 125, a ROM 124, a charging circuit 106, a discharging circuit 107, a recording head 3, and an electrolytic capacitor 105. Have. Further, a field effect transistor (FET) 103 and a transistor 104 are included. In the present embodiment, “power supply power” refers to power supplied from the power supply circuit 101 to the recording head 3.

  The power supply circuit 101 is a so-called power supply unit, and is an AC / DC converter that generates a DC voltage for driving the head from an AC power supply (not shown). In FIG. 1, the DC voltage output from the power supply circuit 101 is denoted as VM. The power supply voltage of the head 3, that is, the voltage of the electrolytic capacitor 105 is denoted as VH.

  The printer control CPU 123 is a central processing unit that controls the entire recording apparatus, and controls the operation of the entire printer by executing a program or starting up hardware.

  The ROM 124 stores programs and setting parameters for controlling the entire printer. The RAM 125 converts a print job received from the outside into print data, is used as a work area for developing a program, and temporarily stores parameters and image data.

  The head power supply control block 102 has a head power supply control sequencer 122 and a circuit 121 for detecting the power supply voltage of the head, and controls the power supplied to the head. The voltage detection circuit 121 detects a voltage value (head power supply voltage value) of a power supply line that supplies power to the recording head. Hereinafter, the head power supply voltage value is also referred to as “electrolytic capacitor voltage value”. This is because the voltage of the electrolytic capacitor 105 is the same as the head power supply voltage. The voltage detection circuit 121 may be an AD converter or a circuit in which a plurality of comparators are arranged to have a plurality of threshold values. The head power supply voltage is divided by the resistors 111 and 112 and input to the voltage detection circuit 121 from the input terminal PI1. The head power supply control sequencer 122 controls on / off of the transistor 104 by outputting a signal from PO1. Further, the current values of the charging circuit 106 and the discharging circuit 107 are controlled. Further, the head power supply control sequencer 122 controls the current value supplied by the charging circuit 106 by outputting a signal from PO2, and controls the current value discharged by the discharging circuit 107 by outputting a signal from PO3. .

  Further, although not shown, the head power supply control block 102 has a timer for measuring the continuous supply time of high power to the head power supply by opening the gate of the FET 103.

  The CPU 123 and the head power supply control block 102 may be mounted on the LSI as the same integrated circuit, or may be mounted as separate LSIs.

  The recording head 3 (print head) corresponds to the power load and performs a printing operation. In the present embodiment, the recording head 3 has an ink tank for each color, and performs recording by ejecting ink droplets onto a recording medium (for example, paper). The recording head 3 may eject ink while moving in a direction orthogonal to the paper transport direction along the shaft that supports the head carriage, or the nozzle array of each color along the paper transport direction. It may have a line head having In this embodiment, the printer is a serial printer that ejects ink while moving a head carriage including a head in a direction orthogonal to the transport direction along a shaft that supports the head carriage. The printer according to the present embodiment performs printing by a thermal method, and a plurality of heaters are provided in the vicinity of the ink discharge ports. When ink is ejected, the ink is instantly foamed by supplying power to the heater, and the ink is ejected by the kinetic energy of the foaming. That is, the recording head according to this embodiment is a thermal head.

  The electrolytic capacitor 105 is an electrolytic capacitor that supplies power to the recording head 3, and also serves to absorb load fluctuations that change depending on the ink discharge status. The electrolytic capacitor 105 is connected to the power supply line in parallel with the head power supply. In the present embodiment, the electrolytic capacitor 105 is a capacitor having a small equivalent series resistance value and a large capacity. By using the electrolytic capacitor 105 having a large capacity, a large charge accumulated in the electrolytic capacitor 105 is supplied as instantaneous power when an image having a high density is formed. As a result, even in a situation where a large current flows instantaneously, a drop in the heater driving voltage can be prevented and stable ink ejection can be realized.

  The FET 103 is turned on when the recording head 3 requires a large amount of power to perform a printing operation. In this embodiment, the gate is opened and closed by turning on and off the transistor 104 with a PMOS. The transistor 104 is connected to the output terminal PO1 of the head power supply control block 102, and is turned on / off by a signal High / Low output from the head power supply control sequencer 122. In this embodiment, when the electrolytic capacitor 105 is charged by the charging circuit 106, the FET 103 is turned off.

  The charging circuit 106 is a circuit for charging the electrolytic capacitor 105, and the discharging circuit 107 is a circuit for discharging the electrolytic capacitor 105.

  The charging circuit 106 limits the current value of the power supplied from the power supply circuit 101 and charges the electrolytic capacitor 105. The charging circuit 106 is a constant current circuit having a current mirror configuration, includes an FET and a constant current source 108, and generates a reference current by the constant current source 108. The constant current source 108 is controlled by the output terminal PO2 of the head power supply control block 102, and the current value can be switched in a plurality of stages.

  Similarly to the charging circuit 106, the discharging circuit 107 is a constant current circuit having a current mirror configuration, includes an FET and a constant current source 108, and the constant current source 109 generates a reference current. In addition, the constant current source 109 is connected to the output terminal PO3 of the head power supply control block 102, and the current value can be switched in a plurality of stages in the same manner as the constant current source 108.

  Here, the serial printer according to the present embodiment prints on the paper that is the recording medium while moving the head 3 in the first direction, and then moves the head 3 on the paper while moving in the second direction opposite to the first direction. Print. When the moving direction of the head 3 is switched, it is determined whether or not the power supply to the head 3 is switched, and the power supply is turned on / off as necessary. Hereinafter, printing by moving in any one direction is referred to as one scan.

  The head power supply control sequence will be described with reference to the flowchart of FIG. 2 and the timing chart of FIG. The flowchart of FIG. 2 is a flowchart showing the power supply operation to the recording head. FIG. 3 is a timing chart showing charging and discharging of the electrolytic capacitor, and a part of the flow of FIG. 2 is shown in the timing chart.

  The flowchart shown in FIG. 2 is realized, for example, when the CPU 123 reads a program stored in the ROM 124 into the RAM 125 and executes it. Specifically, a flow is shown in which the printer receives a print command and the head 3 is turned on from the state where the head 3 is not turned on to perform the printing operation.

  When the printer receives a print command, control of the power supply voltage is started (S201), and the electrolytic capacitor 105 is charged (S202 to S206). First, it is confirmed that no voltage is applied to the head before voltage application to the head 3 is started. Specifically, it is determined whether the VH voltage (capacitor voltage) is equal to or lower than the threshold value Vth11 (S202: refer to timing 302 in FIG. 3).

  When a voltage exceeding the threshold value Vth11 is detected, that is, when it is determined that the VH voltage (capacitor voltage) exceeds the threshold value Vth11 (No in S202), it is determined as a VH monitor error (S213). VH monitor error 1 means that an abnormal voltage is applied to the recording head. If it is determined that the VH monitor error is 1, error processing is performed. The error process is a process for terminating the power supply to the head 3 via the power supply line. Specifically, the FET 103 in FIG. 1 is turned off and the charging circuit 106 is turned off. Further, the power supply of the power supply circuit 101 is turned off. Further, it may be controlled such that the discharge circuit 107 is turned on to positively discharge.

  When it is determined that the VH voltage (capacitor voltage) is equal to or lower than the threshold Vth11 (Yes in S202), the charging circuit 106 is operated to start charging the electrolytic capacitor 105 (S203: see timing 303 in FIG. 3). Specifically, the head power supply control sequencer 122 outputs a signal corresponding to the limit current value of the charging circuit 106 from the output terminal PO2, and outputs a Low signal from the output terminal PO1.

  Wait until a predetermined time set according to the charging capacity of the charging circuit 106 and the capacity of the electrolytic capacitor 105 elapses (S204: refer to timing 304 in FIG. 3). After a predetermined time has elapsed, it is determined whether the VH voltage (capacitor voltage) is equal to or higher than the threshold value Vth12 (S205: see timing 305 in FIG. 3).

  When the VH voltage (capacitor voltage) is less than the threshold value Vth12, that is, less than the threshold voltage value (No in S205), it is determined as a VH monitor error (S214). The VH monitor error 2 is an error that may cause a failure in the print head or the power supply circuit. If it is determined that the VH monitor error is 2, error processing is performed.

  When the VH voltage (capacitor voltage) is equal to or higher than the threshold value Vth12 (Yes in S205), the transistor 104 is turned on, and high power can be supplied to the head (S206: see timing 306 in FIG. 3). Here, the large power refers to power for driving the head 3 supplied from the power supply device. A timer for measuring the continuous power supply time is started simultaneously with the start of the large power supply to the head power supply (S217). That is, the timer is started when the power supply to the head is started.

  Thereafter, it is determined whether the VH voltage (capacitor voltage) is equal to or higher than the threshold value Vth13 (S207). When the VH voltage (capacitor voltage) is less than the threshold value Vth13, that is, less than the threshold voltage value (No in S207), it is determined as VH monitor error 3. The VH monitor error 3 is an error that may cause a failure in the print head or the power supply circuit. If VH monitor error 3 is determined, error processing is performed.

  When the VH voltage (capacitor voltage) is equal to or higher than the threshold Vth13 (Yes in S207), the head power supply control sequencer 122 outputs a High signal from the output terminal PO1, heats the heater of the head (S208), and performs printing (S209). ). That is, during the printing operation, a large amount of power is supplied from the power supply circuit 101 from the power supply line from the power supply circuit 101 via the FET 103 that is the power supply line. Here, in the serial printer, printing is performed by causing the recording head 3 to scan in the first direction, and the recording head drive direction is reversed to the second direction (time for switching the moving direction of the recording head). Exists. Therefore, after printing is started, it is checked whether it is between print scans (S210). If printing for one scan is completed and scanning is in progress (Yes in S210), and printing of one page is not completed (No in S211), it is determined whether the time T specified by the timer is equal to or greater than the threshold Tth ( S218). Here, the threshold value Tth is a value set in consideration of a time during which the head or the power supply circuit can be safely stopped even if a failure has occurred. More specifically, the threshold value Tth is set based on the time during which it can be safely stopped and the time required for one scan. In the present embodiment, the threshold Tth is, for example, 1 to 10 seconds, but is not limited to this.

  If the time T measured by the timer is not equal to or greater than the threshold Tth, that is, less than the threshold Tth (No in S218), the next printing is resumed without turning off the large power supply to the head power supply (S409).

  When the timer value T is equal to or greater than the threshold value Tth (Yes in S218), a low signal is output from the output terminal PO1 and the transistor 104 is turned off to stop the supply of large power to the head (S212). Then, the power supply timer is reset (S219), and the process returns to the head leak check (S205). That is, the timer is reset when power supply to the head is stopped. Here, the reason why the power supply to the head is stopped is to perform a leak check.

  If printing for one scan is completed and the period is between scans (Yes in S210), and printing of one page is completed (Yes in S211), a print end sequence is executed (S216). Specifically, the charge of the electrolytic capacitor 105 is discharged by turning off the charging circuit 106 and operating the discharging circuit 107 at the timing 315 in FIG.

  Although not shown, whether the VH voltage (capacitor voltage) is equal to or higher than the threshold value Vth13 is determined while the FET 103 is on, that is, after S206 and before executing the print end sequence or at S212. Until it stops, it is executed at a predetermined cycle. For example, the determination is made every 5 msec. When the VH voltage (capacitor voltage) is less than the threshold value Vth13, it is determined as VH monitor error 3.

  Here, control of the current value when the electrolytic capacitor 105 is charged by the charging circuit 106 will be described. That is, S203 corresponds to S401. The flowchart shown in FIG. 4 is realized, for example, when the CPU 123 reads a program stored in the ROM 124 into the RAM 125 and executes it. Specifically, the flow from when the printer receives a print command and the head 3 is not turned on to when the head is turned on and the printing operation is performed is shown.

  Here, Ichg1, Ichg2, and Ichg3 shown in FIGS. 4 and 5 are charging currents output from the charging circuit 106, respectively, and are switched according to the voltage state of the electrolytic capacitor. Specifically, when the voltage of the electrolytic capacitor monitored by the voltage detection circuit 121 exceeds preset voltage threshold values (Vth1, Vth2), the charging current value is increased to a predetermined value (Ichg2, Ichg3). Thus, in the present embodiment, by switching the charging current value, charging can be completed as quickly as possible while satisfying the thermal limitation of the FET of the charging circuit 106. In the present embodiment, the heat calculated by the product of the potential difference between the source and drain of the FET of the charging circuit 106 and the current value output from the charging circuit 106 is set to be equal to or less than the allowable loss of the FET of the charging circuit 106. To do. For example, when the potential difference between the source and the drain is VM−Vth1 and the current value is Ichg1, the amount of heat generated in the charging circuit 106 is expressed as (VM−Vth1) × Ichg1. Similarly, when the potential difference between the source and the drain is VM−Vth2 and the current value is Ichg2, the amount of heat generated in the charging circuit 106 is expressed as (VM−Vth2) × Ichg2. When the potential difference between the source and the drain is VM−Vth3 and the current value is Ichg3, the amount of heat generated in the charging circuit 106 is expressed as (VM−Vth3) × Ichg3. All of (VM−Vth1) × Ichg1, (VM−Vth2) × Ichg2, and (VM−Vth3) × Ichg3 are set to be equal to or less than a certain allowable loss. Therefore, the current value Ichg1 when the potential difference with the VM is less than Vth1 is relatively small, and Ichg3 when the potential difference with the VM is less than Vth2 is relatively large. In the present embodiment, the switching of the current value is shown in three stages, but is not limited to this, and the number of switching of the current value may be more or less than three. First, the head power supply control sequencer 122 outputs a signal from the output terminal PO2 so as to select Ichg1 as the charging current value of the charging circuit 106 (S402), and the voltage of the electrolytic capacitor detected by the voltage detection circuit 121 is equal to or higher than Vth1. (S403). If it is determined that the voltage of the electrolytic capacitor is equal to or higher than Vht1 (Yes in S403), the head power supply control sequencer 122 outputs a signal from the output terminal PO2 so as to select Ichg2 as the charging current value of the charging circuit 106 (S404). That is, the charging current value of the charging circuit 106 is switched from Ichg1 to Ichg2. Then, it is determined whether the voltage of the electrolytic capacitor detected by the voltage detection circuit 121 is Vth2 or more (S405). If it is determined that the voltage of the electrolytic capacitor is equal to or higher than Vht2 (Yes in S405), the head power supply control sequencer 122 outputs a signal from the output terminal PO2 so as to select Ichg3 as the charging current value of the charging circuit 106 (S406). That is, the charging current value of the charging circuit 106 is switched from Ichg2 to Ichg3.

  FIG. 5A is a timing chart of the voltage of the electrolytic capacitor 105 monitored by the voltage detection circuit 121. FIG. 5B is a timing chart showing the charging current and discharging current to the electrolytic capacitor, and FIG. 5C is a timing chart showing the voltage level of PO1.

  During the period 310 during which the electrolytic capacitor 105 is charged, the voltage rise curve becomes steep. As shown in FIG. 5B, the charging current value is switched from Ichg1 to Ichg2 at a timing 301 when the electrolytic capacitor voltage becomes equal to or higher than the threshold value of Vth1, and charging is performed at a timing 302 when the electrolytic current becomes equal to or higher than the threshold value of Vth2. This is because the current value is switched from Ichg2 to Ichg3.

  After Ichg3 is selected, it is determined whether the voltage of the electrolytic capacitor detected by the voltage detection circuit 121 is equal to or higher than Vth3 (S407). If it is determined that the voltage of the electrolytic capacitor is equal to or higher than Vht3 (Yes in S407), the head power supply control sequencer 122 outputs a signal from the output terminal PO2 so as to select the voltage holding current value Ikeep as the charging current value of the charging circuit 106. (S408). That is, the charging current value of the charging circuit 106 is switched from Ichg1 to Ikeep. The current value Ikeep is a current value that can detect an increase in leakage while maintaining the voltage of the electrolytic capacitor 105. Therefore, the Ikeep current value is set to a value lower than the value when the charging current value is increased (for example, Ichg3). In the present embodiment, the Ikeep current value is set to a value lower than Ichg1, that is, a value lower than the current value supplied by the charging circuit 106 during charging.

  Thereby, the charging of the electrolytic capacitor 105 by the charging circuit 106 is completed (S409).

  Although not shown, in the present embodiment, the charging circuit 106 is kept on even during printing of the printing operation or during printing stop, and the Ikeep current is supplied to the electrolytic capacitor 105 via the charging circuit.

  Here, when the large-capacity power supply is stopped and the leak is detected every time between scans, since the heater current cannot flow through the head, the head dissipates heat and the temperature decreases. However, in order to perform stable ink ejection, it is necessary to preheat the head to a certain temperature before applying power for ejection. Therefore, after heating so that the head temperature rises to a certain temperature, the printing operation is started. As described above, when the operation of stopping the power supply to the head and heating again each time between scans is repeated, the printing time becomes long. In other words, the printing speed decreases. In particular, if the amount of heat released when detecting a leak is large, it takes a long time to reheat the head. By increasing the heating capacity, the time for reheating the head can be shortened. However, if the heating capacity is increased too much, fine temperature control becomes difficult.

  In contrast, in this embodiment, the frequency of head reheating is limited, that is, by reducing the frequency of head reheating, the ratio of the heating time to the total printing time is suppressed, and the printing time is shortened. can do. Even within the threshold Tth time set based on the time that can be safely stopped even if a failure has occurred in the head or power supply circuit, the leak check is not performed even between scans, and the set time has passed. Turn off the power supply to the head to check for leaks. As a result, the power supply off period for leak check and the time for reheating the heater can be reduced, and the power supply can be properly supplied in the event of an abnormality in the head or power supply circuit while shortening the printing time. Can be stopped.

  In addition, when heating and heat insulation are performed using a heater different from that for ink ejection, cost is increased. On the other hand, in this embodiment, by controlling the power supply time to the head, stable ink ejection can be realized without providing a new heater.

  In the case of a serial printer that can print on large size paper, the printing width required for one scan differs greatly between A3 size printing and L size printing, and frequent scanning for L size printing. It takes in the middle. Here, when the time Tth that is twice or more than the time required for one scan can be set as the threshold value Tth, the frequency of the leak check can be set to at least once every two scans, and the time that is three times or more can be set. In some cases, it can be set to once every three scans.

  As described above, if a leak check that occurs between scans is performed regardless of the document size, the printing time per sheet becomes longer. On the other hand, in this embodiment, by performing the leak check at the timing when the set time has elapsed, the number of times of reheating the head can be reduced, and the printing time can be shortened. In particular, the number of leak checks can be reduced when performing small-size printing with a short printing time per scan.

  As described above, according to the present embodiment, the leakage current of the head can be detected appropriately without compromising the performance of the printer, and both the performance and safety of the printer can be achieved.

  If a soft start circuit is added to the AC / DC converter or a switch that can withstand the inrush current is prepared in order to suppress the inrush current, the cost is likely to increase. On the other hand, in this embodiment, since the current value supplied to the power supply circuit by the charging circuit 106 is limited, an inrush current to the FET 103 can be prevented.

  Furthermore, when increasing the value of Ichg in order to shorten the charging time of a large-capacity electrolytic capacitor, it is necessary to select an FET with a large allowable loss, which may lead to an increase in cost. On the other hand, in the present embodiment, by switching the current according to the allowable loss of the FET of the charging circuit 106, the charging time of the electrolytic capacitor is shortened to the extent that the target performance of the recording apparatus is reached, and the cost of the FET 103 is reduced. An increase can be prevented.

  As described above, according to the present embodiment, the leakage current of the head can be detected appropriately without compromising the performance of the printer, and both the performance and safety of the printer can be achieved.

(Other embodiments)
The present invention is not limited to the embodiment described above. For example, in the above-described embodiment, the power supply device includes the head as the power load. However, the power supply device is not limited thereto, and may not include the power load. That is, it may be connectable to a power load and supply power to the power load.

  In the above-described embodiment, the timing for performing the head leak check is between scans of the serial printer. However, the present invention is not limited to this, and between the head pre-heat treatment and the scan and when the pre-heat time is required to be long. It may be between the preheating time and the preheating time.

  In the embodiment described above, the current value supplied by the charging circuit 106 is switched when the electrolytic capacitor 105 is charged. However, the present invention is not limited to this, and the current value supplied by the charging circuit 106 is constant. It may be a current value.

  In the embodiment described above, the power supply device is a printer, but is not limited to this, and any device that supplies power to a load may be used.

Claims (11)

A power supply device for supplying power to a power load capable of moving in a first direction and moving in a second direction opposite to the first direction,
A power supply for supplying power to the power load via a power supply line during operation of the power load;
A capacitor connected to the power supply line connecting the power supply unit and the power load;
A specifying means for specifying a time elapsed since the start of power supply to the power load via the power supply line;
A determination means for determining whether the power load is moving between the movement in the first direction and the movement in the second direction;
Detecting means for detecting a voltage value of the capacitor;
Execution means for executing error processing based on the voltage value detected by the detection means,
The detection means includes
The voltage value of the capacitor in a state in which power supply through the power supply line is stopped when the determination means determines that the movement is being performed and the time specified by the specification means has passed a predetermined time. and it performs the detection process of detecting a
Even if it is determined by the determining means that the time is between the movements, if the time specified by the specifying means has not passed the predetermined time, the power supply device is not executed .   The power supply apparatus according to claim 1, wherein the execution unit executes the error process when the voltage value detected by the detection unit is less than a predetermined voltage value.   The power supply apparatus according to claim 1, wherein the error process is a process of terminating power supply to the power load via the power supply line.   The power supply apparatus according to claim 3, wherein the execution unit turns off the power supply of the power supply unit. 5. The power supply device according to claim 1, wherein the predetermined time is a time that is two or more times longer than a time required for the power load to move in the first direction .   The specifying means is a timer that starts power supply to the power load via the power supply line at the start, and the timer is reset when large power supply to the power load via the power supply line is stopped The power supply device according to claim 1, wherein the power supply device is a power supply device. The power load is a print head of a serial printer,
The determination unit determines whether the scan between the scan in the first direction and the scan in the second direction of the print head;
The detection means includes
Wherein the determining means is determined to be between scans of the printhead, and wherein when a time specified by the specifying means has passed the predetermined time, executes the detection process,
The detection processing is not executed when the time specified by the specifying means has not passed the predetermined time even if it is determined by the determining means that it is between scans of the print head. Item 7. The power supply device according to any one of Items 1 to 6.   The power supply apparatus according to claim 7, wherein the power load is a thermal head of a serial printer.   The power supply apparatus according to claim 1, comprising the power load. A print head capable of scanning in a first direction and scanning in a second direction opposite to the first direction;
A power supply for supplying power to the print head via a power supply line during operation of the print head;
A capacitor connected to the power supply line connecting the power supply unit and the print head;
A specifying means for specifying a time elapsed since the start of power supply to the print head via the power supply line;
Determining means for determining whether the scan between the scan in the first direction and the scan in the second direction of the print head;
Detecting means for detecting a voltage value of the capacitor;
Execution means for executing error processing based on the voltage value detected by the detection means, and the detection means
When it is determined by the determining means that the print head is being scanned, and the time specified by the specifying means has passed a predetermined time, the power supply via the power supply line is stopped and the capacitor is stopped. Execute the detection process to detect the voltage value of
Even if it is determined by the determination means that it is between scans of the print head, if the time specified by the specification means does not pass the predetermined time, the detection process is not executed. . A power supply for supplying power to the power load during operation of the power load capable of moving in a first direction and moving in a second direction opposite to the first direction ;
A capacitor connected to a power supply line connecting the power supply unit and the power load;
A method for controlling a power supply apparatus comprising:
A specifying step for specifying a time that has elapsed since the start of power supply to the power load via the power supply line ;
A determination step for determining whether the power load is moving between the movement in the first direction and the movement in the second direction;
A detection step of detecting a voltage value of the capacitor;
An execution step of performing error processing based on the voltage value detected by the detection step,
The voltage value of the capacitor in a state in which power supply through the power supply line is stopped when it is determined in the determination step that it is between the movements and the time specified in the specific step has passed a predetermined time. Execute detection process to detect
Even if it determines with it being between the said movements in the said determination process, when the time specified in the said specific process has not passed the said predetermined time, the said detection process is not performed, The control method characterized by the above-mentioned .

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