JP2010076264A - Printer and voltage control apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress an influence of counter-electromotive force of a motor in an appropriate manner. <P>SOLUTION: A printer performs printing which includes a motor for driving a carriage to move a print head and a voltage controller 18 for controlling voltage of electric power supplied to the motor from a constant voltage power source 22. The voltage controller 18 has: a voltage increase detector 104 for detecting increase of voltage of a node 110 between the power source and the motor; a switch 108 for flowing current when the voltage of the node 110 between the power source and the motor is increased higher than the output voltage of the constant voltage power source 22, because the switch opens or closes according to the output of the voltage increase detector 104; and a current consumer 106 for consuming current when the switch 108 flows the current. The voltage increase detector 104 has a CPU 152 operating according to a program for operation control, and controlling opening and closing of the switch 108, based on a reference voltage predetermined by the program. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing apparatus and a voltage control apparatus.

  Conventionally, various devices that are driven by the power of a motor are known. As such an apparatus, for example, a printing apparatus is known in which a carriage for moving a print head such as an inkjet head is repeatedly driven by a motor such as a servo motor. Such a printing apparatus performs printing by, for example, driving a carriage to reciprocate a print head in a predetermined main scanning direction.

  In the configuration using such a motor, back electromotive force is generated when the motor is decelerated. Further, the back electromotive force of the motor may be returned to the power supply device through a motor drive circuit (motor driver circuit) or the like. However, if the back electromotive force of the motor returns to the power supply device, for example, an abnormal increase in voltage may occur, which may cause malfunction of a circuit such as the power supply device. In addition, an overvoltage is applied to the control element, which may cause a failure.

  To cope with this, for example, a method of attaching a bleeder resistor to the load line and consuming power, or a method of responding by attaching a surge absorber such as a varistor to the load line can be considered. However, in such a method, for example, wasteful power consumption is always generated.

  Furthermore, in the method using a bleeder resistor, for example, a large wattage power resistor is required to consume a sufficient amount of power, the scale of the circuit configuration increases, the device becomes larger, and the cost increases. There is also a risk of an increase. In the method using a varistor, for example, it is necessary to change the voltage value of the varistor according to the circuit configuration according to the power supply voltage or the like. Therefore, depending on the circuit configuration, there may be no product that matches the required voltage value.

  Conventionally, a configuration is also known in which a counter electromotive force is detected using a Zener voltage of a Zener diode and the counter electromotive force is removed (see, for example, Patent Document 1). However, the Zener voltage of the Zener diode has a large variation between elements. For example, in general, the variation in Zener voltage is about 10%. Therefore, in this case, setting the voltage may be difficult if the circuit is to be operated reliably. In addition, for example, fine adjustment of the voltage setting may be difficult. Furthermore, a detection circuit using a Zener diode has a problem that it is difficult to set an arbitrary voltage.

Therefore, conventionally, it has been required to suppress the influence of the counter electromotive force of the motor by a more appropriate method. Accordingly, an object of the present invention is to provide a printing apparatus and a voltage control apparatus that can solve the above-described problems.
JP-A-6-343291

In order to solve the above problems, the present invention has the following configuration.
(Configuration 1) A printing apparatus that performs printing, and includes a print head, a carriage that moves the print head, a motor that provides power to the carriage, and voltage control that controls the voltage of power supplied from the constant voltage power source to the motor. The voltage control unit includes a voltage increase detection unit that detects that the voltage of the node between the motor power sources, which is a node between the constant voltage power source and the motor, rises higher than the output voltage of the constant voltage power source, When the voltage at the node between the motor power supplies rises above the output voltage of the constant voltage power supply by opening and closing according to the output of the voltage rise detection unit, provided separately from the path connecting the voltage power supply and the motor And a current consumption unit that consumes the current when the switch conducts current. The voltage rise detection unit operates according to a program for operation control, and As the reference become voltage for detecting a rise in the voltage of the power supply between the nodes, with a CPU that uses a preset reference voltage by the program.

  This program is, for example, firmware for operation control of the printing apparatus. For example, when the voltage at the node between the motor power supplies is higher than the output voltage of the constant voltage power source by a predetermined offset voltage or more, the voltage rise detection unit causes the voltage at the node between the motor power supplies to be higher than the output voltage of the constant voltage power source. Detect the rise.

  For example, the CPU may control opening and closing of the switch via the other element by supplying a reference voltage according to the program to the other element. Further, the CPU may control opening and closing of the switch by directly controlling the switch according to the comparison result with the reference voltage. For example, when the voltage at the node between the motor power supplies is higher than the reference voltage, the CPU opens the switch and causes a current to flow through the switch.

  If comprised in this way, the raise of the voltage by back electromotive force can be detected appropriately, for example. In addition, by providing a current consumption unit that is a dedicated circuit that consumes the counter electromotive force, a voltage increase due to the counter electromotive force can be appropriately suppressed to a certain level or less. Thereby, for example, malfunction of a circuit such as a power supply device and overvoltage of the control element can be appropriately prevented. Furthermore, by using a circuit structure that operates only when a back electromotive force is generated, current can be consumed only when it is dynamically required. Thereby, power consumption can be suppressed appropriately.

  Further, in such a configuration, the reference voltage used for detecting the increase in the voltage of the node between the motor power supplies can be flexibly set with a high degree of freedom by a program such as firmware. Therefore, for example, voltage setting is not difficult, and a circuit can be designed with high freedom. Further, for example, the reference voltage can be easily changed when adjusting the operation of the circuit or changing the specification.

  Furthermore, for example, compared with the case where the reference voltage is set by using the Zener voltage of the Zener diode, it is possible to appropriately suppress the variation in element characteristics and the influence of errors. Therefore, if comprised in this way, the raise of the voltage of the node between motor power supplies can be detected appropriately with high precision, for example.

  Here, in this configuration, the motor is, for example, a DC motor. The motor may be a servo motor. In addition, the current consumption unit consumes current, for example, by a resistor. The current consumption unit preferably has a plurality of resistors that allow current to flow in parallel. As this resistance, for example, a power resistance of a surface mount product can be suitably used. The current consumption unit may consume current by a configuration other than the resistor.

  The CPU is, for example, a microcomputer. This CPU may be a CPU core of a microcomputer. The CPU may be a CPU that controls the operation of the entire printing apparatus, for example. If comprised in this way, cost can be reduced compared with the case where a CPU for exclusive use is provided in a voltage rise detection part, for example. The CPU of the voltage rise detection unit may be provided separately from the CPU that controls the operation of the entire printing apparatus.

  (Configuration 2) The voltage rise detection unit includes a digital-analog conversion circuit that converts an input digital signal into an analog signal, a voltage at a node between motor power supplies, and a voltage of the analog signal converted by the digital-analog conversion circuit. A comparator for comparing, and the CPU outputs a digital signal designating a reference voltage to the digital-analog conversion circuit according to a program, and the switch opens and closes according to the output of the comparator, whereby the motor power supply node Current flows when the voltage rises above the output voltage of the constant voltage power supply.

  If comprised in this way, a reference voltage can be set appropriately with a high freedom degree, for example. Further, for example, an increase in the voltage of the node between the motor power supplies can be appropriately detected using the CPU.

  For example, the comparator receives a voltage obtained by dividing the voltage of the node between the motor power sources by a resistor, and thereby compares the voltage of the node between the motor power sources and the voltage of the analog signal converted by the digital-analog converter circuit. Good. The digital-analog conversion circuit may be a circuit built in the microcomputer together with the CPU core of the microcomputer, for example. If comprised in this way, the raise of the cost by providing a digital analog conversion circuit can be suppressed appropriately, for example.

  The digital signal designating the reference voltage is, for example, a logic signal (logic signal) indicating a voltage value of a voltage to be output to the digital / analog conversion circuit in accordance with the reference voltage. For example, the digital-analog conversion circuit receives a logic signal indicating a voltage value, and converts the logic signal into an analog signal having the voltage value. Further, when the comparator receives a voltage obtained by dividing the voltage of the motor power supply node by the resistor, the voltage according to the reference voltage is, for example, a voltage set in consideration of the division ratio.

  (Configuration 3) The voltage rise detection unit further includes an analog-to-digital conversion circuit that outputs a digital signal indicating the voltage of the motor power supply node based on the voltage of the motor power supply node, and the CPU controls opening and closing of the switch. Outputs the output signal and receives the digital signal from the analog-to-digital conversion circuit to detect the voltage of the motor power supply node and changes the output signal when it is determined that the voltage of the motor power supply node is higher than the reference voltage To open the switch and pass current through the switch.

  If comprised in this way, the voltage of the node between motor power supplies can be detected appropriately using CPU, for example. Thereby, for example, the reference voltage set by the program can be appropriately compared with the voltage of the node between the motor power supplies. Further, this comparison can appropriately detect, for example, an increase in the voltage of the motor power supply node using the CPU.

  Further, in this case, the comparison between the voltage at the node between the motor power supplies and the reference voltage may be performed by the CPU by comparing the numerical value indicated by the digital signal with the numerical value indicating the reference voltage. Therefore, it is not necessary to provide a comparator for comparison and the circuit design is facilitated. In addition, since it is not necessary to actually output a voltage corresponding to the reference voltage, the reference voltage can be appropriately set with a higher degree of freedom.

  The analog-digital conversion circuit may be a circuit built in the microcomputer together with the CPU core of the microcomputer, for example. If comprised in this way, the raise of the cost by providing an analog-digital conversion circuit can be suppressed appropriately, for example.

  The analog-digital conversion circuit converts, for example, an input analog signal into a logic signal indicating the voltage of the analog signal. Further, for example, the CPU detects the voltage of the motor power supply node based on the logic signal received from the analog-digital conversion circuit.

  (Configuration 4) The current consumption unit includes a heater, and heats a medium used in the printing apparatus by heat generated by the heater according to consumption of current received through the switch.

  If comprised in this way, the electric power consumed in an electric current consumption part can be utilized effectively. The power consumption by the current consumption unit is used as part of the power consumption of the heater, for example. In this case, at a timing when no current flows to the current consumption unit, the heater may heat the medium according to, for example, power received from another power source.

  (Configuration 5) The printing apparatus is a printing apparatus that uses ultraviolet irradiation type ink that is cured by irradiation with ultraviolet rays, and the current consumption unit is a charger that charges current received through the switch, and a medium that is used in the printing apparatus. A light source for irradiating the upper ink with ultraviolet light, and the ink is cured by the ultraviolet light generated by the light source according to the consumption of the current charged in the charger.

  If comprised in this way, the electric power consumed in an electric current consumption part can be utilized effectively. Moreover, by using a charger, for example, ultraviolet rays can be irradiated at an appropriate timing regardless of the operation timing of the motor. The power consumption by the current consumption unit may be used as part of the power consumption of the light source, for example. In this case, the light source may receive further current from another power source, for example.

  (Configuration 6) A voltage control device for controlling the voltage of power supplied from a constant voltage power source to a motor, wherein a voltage at a node between motor power sources, which is a node between the constant voltage power source and the motor, is output from the constant voltage power source. A voltage rise detector that detects that the voltage rises above the voltage and a path that connects the constant voltage power supply and the motor are provided in a separate path. The motor power supply is opened and closed according to the output of the voltage rise detector. A switch that flows current when the voltage of the internode rises above the output voltage of the constant voltage power supply, and a current consumption unit that consumes the current when the switch flows current. It has a CPU that operates according to a control program and uses a reference voltage preset by the program as a reference voltage for detecting an increase in the voltage of the node between the motor power supplies.

  If comprised in this way, the effect similar to the structure 1 can be acquired, for example. Similar effects can be obtained in various apparatuses other than the printing apparatus. For example, in various apparatuses other than the printing apparatus, the influence of the back electromotive force of the motor can be suppressed by an appropriate method.

  According to the present invention, the influence of the back electromotive force of the motor can be suppressed by an appropriate method.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. FIG. 1 shows an example of the configuration of a printing apparatus 10 according to an embodiment of the present invention. In this example, the printing apparatus 10 is an inkjet printer that performs printing on a medium 50, and includes a print head 12, a carriage 14, a motor 16, a main circuit board 18, a voltage control unit 20, and a constant voltage power supply 22.

  The print head 12 is an inkjet head that ejects ink droplets onto the medium 50. The carriage 14 is a head drive device that moves the print head 12, and causes the print head 12 to perform a scanning operation by reciprocating the print head 12 in a predetermined main scanning direction according to the power of the motor 16.

  The motor 16 is a DC motor such as a servo motor, for example, and applies power to the carriage 14 in accordance with electric power received from the constant voltage power supply 22 via the main circuit board 18 and the voltage control unit 20. The main circuit board 18 is a circuit board on which electronic components such as LSIs for controlling the operation of the printing apparatus 10 are mounted. In this example, the main circuit board 18 transmits the power received from the constant voltage power supply 22 via the voltage control unit 20 to the motor 16 according to a preset sequence. Thereby, the main circuit board 18 controls the operation of the motor 16. Further, the scanning operation of the print head 12 is controlled by controlling the operation of the motor 16.

  The voltage control unit 20 is a voltage control device that controls the voltage of power supplied from the constant voltage power supply 22 to the motor 16, and is provided between the main circuit board 18 and the constant voltage power supply 22. In this example, the voltage control unit 20 detects an increase in voltage due to the counter electromotive force of the motor 16 when the main circuit board 18 decelerates the motor 16, for example. When an increase in voltage is detected, an excessive increase in the voltage is prevented by consuming a current through a path different from the power supply to the motor 16. Thereby, the voltage control unit 20 prevents malfunction of a circuit such as the constant voltage power source 22 of the motor 16 and overvoltage of the control element. The configuration of the voltage control unit 20 will be described in detail later.

  The constant voltage power supply 22 is a DC power supply that supplies electric power for driving the motor 16. The constant voltage power supply 22 may be a power supply that converts AC power into DC power, for example. In this example, the constant voltage power supply 22 is a 42 V power supply, and supplies power of a 42 V voltage to the motor 16 via the voltage control unit 20 and the main circuit board 18. The constant voltage power supply 22 may be a switching power supply.

  According to this example, the scan operation can be performed by the print head 12 by the power of the motor 16. This also makes it possible to appropriately print on the medium 50.

  FIG. 2 is a circuit diagram illustrating a first example of the configuration of the voltage control unit 20. In this example, the voltage control unit 20 includes a connection unit 102, a voltage rise detection unit 104, a switch 108, and a current consumption unit 106. The voltage control unit 20 is connected to a 5V constant voltage power source at a location indicated as + 5V in the drawing. The voltage control unit 20 is grounded at a location indicated by a downward triangle in the drawing.

  The connection part 102 is a part for connecting the constant voltage power supply 22 and the main circuit board 18 and includes a connector CN1 and a diode D1. The connector CN1 is a connector connected to the main circuit board 18 and transmits the power supplied from the constant voltage power supply 22 to the main circuit board 18. In this example, the connector CN1 further supplies 5V power to the main circuit board 18.

  The diode D1 is an element that separates the motor 16 (see FIG. 1) and the main circuit board 18 from the constant voltage power supply 22, and in the supply path of 42V power from the constant voltage power supply 22 to the main circuit board 18, The cathode is provided in the forward direction facing the main circuit board 18 side. Thereby, the diode D1 prevents the backflow of an electric current. This also prevents the influence of the voltage rise from reaching the constant voltage power supply 22.

  The voltage rise detection unit 104 is a circuit that detects a rise in the voltage of the motor power supply node 110 that is a node between the constant voltage power supply 22 and the motor 16. Detects that the output voltage rises. In this example, the motor power supply node 110 is a node between the main circuit board 18 on the motor 16 side and the constant voltage power supply 22 with respect to the voltage control unit 20.

  In this example, the voltage rise detection unit 104 includes a CPU 152, a digital-analog conversion circuit (DAC) 154, a comparator U1A, and a plurality of resistors R21 to R24. The CPU 152 is a CPU that operates according to an operation control program such as firmware. In this example, the CPU 152 is a microcomputer (microcomputer), for example. The CPU 152 may be a CPU core of a microcomputer. Further, the CPU 152 may further control the operation of the external configuration of the voltage rise detection unit 104. For example, the CPU 152 may control the entire printing apparatus 10.

  Further, in this example, the CPU 152 outputs a digital signal designating a reference voltage serving as a reference for detecting an increase in the voltage of the motor power supply node 110 to the digital-analog conversion circuit 154 according to the program. The digital signal designating the reference voltage is, for example, a logic signal (logic signal) indicating a voltage value of a voltage to be output to the digital-analog conversion circuit 154 according to the reference voltage.

  The digital-analog conversion circuit 154 is a circuit that converts a digital signal into an analog signal, converts the digital signal received from the CPU 152 into an analog signal, and outputs the analog signal to the (−) terminal of the comparator U1A. In this example, the digital-analog conversion circuit 154 receives a logic signal indicating a voltage value as the digital signal. Then, the logic signal is converted into an analog signal having the voltage value.

  The comparator U1A is a voltage comparator that compares the voltage of the motor power supply node 110 with the voltage of the analog signal that is the output signal of the digital-analog conversion circuit 154. The output of the comparator U1A is pulled up via the resistor R24. Further, in order to give a hysteresis to the circuit and suppress the sensitive switching operation, the output of the comparator U1A is fed back to the (+) terminal via the resistor R23.

  In this example, the comparator U1A receives the voltage of the motor power supply node 110 divided by the plurality of resistors R21 and R22 at the (+) terminal. It is preferable that the plurality of resistors R21 and R22 have sufficiently large resistance values so that the current flowing through them is sufficiently small. The comparator U1A receives the output signal of the digital-analog conversion circuit 154 at the (−) terminal. Then, the voltages at both terminals are compared, and a signal corresponding to the comparison result is output to the switch 108.

  Here, the voltage received by the comparator U1A at the (−) terminal is based on the reference voltage set by the CPU 152, for example, with respect to the voltage obtained by dividing the voltage of the motor power supply node 110 in the normal state by the resistors R21 and R22. The voltage value is set slightly higher than the offset voltage (Vos) of U1A. The voltage of the motor power supply node 110 in the normal state is, for example, a voltage in a state where the voltage of the motor power supply node 110 is not increased due to the influence of the counter electromotive force. Therefore, in the normal state, the comparator U1A outputs an L signal (0 V).

  Further, for example, when the voltage of the motor power supply node 110 increases due to the influence of the counter electromotive force of the motor 16, the voltage of the (+) terminal of the comparator U1A also increases. And according to this voltage rise, comparator U1A inverts an output and outputs H signal (5V). Thereby, the comparator U1A inverts the output in accordance with the change in the voltage of the motor power supply node 110. Therefore, according to the present example, for example, the voltage increase detection unit 104 can appropriately detect an increase in the voltage of the motor power supply node 110 due to the counter electromotive force of the motor 16.

  The switch 108 is provided in a path separate from the path connecting the constant voltage power supply 22 and the motor 16 and opens and closes the current path according to the output of the comparator U1A. In this example, the switch 108 is configured by an N-type MOSFET Q1 that receives the output of the comparator U1A at the gate terminal (G). The drain terminal (D) of the MOSFET Q1 is connected to the downstream side of the current consumption unit 106, and the source terminal (S) is grounded.

  With this configuration, the switch 108 is turned on when the output of the comparator U <b> 1 </ b> A is an H signal, and a current flows through the current consumption unit 106. As a result, the switch 108 responds to the output of the comparator U1A when the voltage of the motor power supply node 110 rises and becomes higher than the reference voltage corresponding to the output voltage of the constant voltage power supply 22 in the normal state. Thus, a current is passed through the current consumption unit 106.

  Note that the switch 108 can be formed of an element other than the MOSFET Q1, for example. For example, the switch 108 can be configured by a bipolar transistor, a relay, or the like.

  The current consumption unit 106 is a dedicated circuit that consumes the counter electromotive force of the motor 16. In this example, the current consumption unit 106 is a circuit that consumes a current using a resistor. The current direction upstream side of the current consumption unit 106 is connected to the motor power supply node 110, and the downstream side is grounded via the switch 108. As a result, the current consumption unit 106 consumes current only when the switch 108 is turned on and current flows.

  In addition, when the voltage of the motor power supply node 110 rises and a current flows through the current consumption unit 106 and the switch 108, when the current consumption unit 106 consumes the current thereafter, the voltage of the motor power supply node 110 drops. As a result, the voltage input to the (+) terminal and the (−) terminal of the comparator U1A returns to the normal state. In response to this, the output of the comparator U1A returns to the L signal, and the switch 108 is turned OFF. Therefore, in a state where the voltage of the motor power supply node 110 is not increased, the switch 108 is OFF and no current flows through the current consumption unit 106.

  According to this example, by providing the current consumption unit 106 that is a dedicated circuit that consumes the counter electromotive force, the voltage increase due to the counter electromotive force can be appropriately suppressed to a certain level or less. Thereby, for example, it is possible to appropriately prevent malfunction of the circuit due to voltage rise and overvoltage of the control element.

  Further, according to this example, the power consumption can be appropriately suppressed by the configuration in which the current consumption unit 106 consumes the current only when necessary. For example, when the output voltage of the constant voltage power supply 22 is + 42V, if an attempt is made to suppress the voltage increase due to the back electromotive force by a static method using a bleeder resistance, for example, the power is always about 42V × 0.24A = 10 W Will be consumed. On the other hand, according to this example, for example, when performing a standard printing operation, the power consumption can be suppressed to about 1 to 2 W.

  Further, according to this example, it is possible to flexibly set a reference voltage serving as a reference for detecting an increase in the voltage of the motor power supply node 110 with a high degree of freedom by a program such as firmware. Therefore, for example, voltage setting is not difficult, and a circuit can be designed with high freedom. Further, for example, the reference voltage can be easily changed when adjusting the operation of the circuit or changing the specification.

  Furthermore, for example, as compared with the case where the reference voltage is set by using the Zener voltage of the Zener diode, it is possible to appropriately suppress the variation in element characteristics and the influence of errors. Therefore, if comprised in this way, the raise of the voltage of the node 110 between motor power supplies can be detected appropriately with high precision, for example.

  In this example, the CPU 152 outputs a digital signal in consideration of voltage division by the resistors R21 and R22 as a digital signal designating the reference voltage. Further, the digital-analog conversion circuit 154 outputs a voltage obtained by dividing the reference voltage by the same ratio to the comparator U1A according to the digital signal. Therefore, according to this example, the voltage of the motor power supply node 110 and the reference voltage can be appropriately compared.

  FIG. 3 shows an example of the configuration of the current consumption unit 106. In this example, the current consumption unit 106 includes a resistance unit 302 and a lighting display unit 304. The resistance unit 302 is a portion in which resistors for current consumption are arranged, and includes a plurality of resistors R2 to R19 that allow current to flow in parallel. The upstream side of the resistors R <b> 2 to R <b> 19 in the current direction is connected to the motor power supply node 110, and the downstream side is connected to the switch 108. Thus, when the switch 108 is turned on, the resistors R2 to R19 cause the current from the motor power supply node 110 to flow and consume. The resistors R2 to R19 preferably flow a current of about 0.5 A in total (for example, 0.4 to 0.6 A), for example.

  In addition, as resistance R2-R19, the power resistance of the surface-mounting goods arrange | positioned on the board | substrate can be used suitably, for example. If comprised in this way, the mounting area of resistance R2-R19 can be reduced appropriately.

  According to this example, when the switch 108 is turned ON, the current flowing from the motor power supply node 110 can be appropriately consumed. In addition, for example, when a back electromotive force of the motor 16 (see FIG. 1) is generated, for example, an increase in the voltage of the motor power supply node 110 can be appropriately suppressed.

  The lighting display unit 304 is a display unit that indicates an operation state of the current consumption unit 106. In this example, the lighting display unit 304 includes a resistor R32 and a light emitting diode D5. The resistor R32 and the light emitting diode D5 are connected in series between the motor power supply node 110 and the switch 108 with the resistor R32 upstream in the current direction.

  Thereby, the resistor R32 determines the value of the current flowing through the light emitting diode D5. The value of the current flowing through the light emitting diode D5 is preferably about 4 mA (for example, 3 to 5 mA). The light emitting diode D5 emits light according to the current flowing through the resistor R32.

  With this configuration, the light emitting diode D5 is lit when the switch 108 is turned on and the resistor 302 consumes current. Further, when the circuit is abnormal, for example, the light emitting diode D5 is always lit as the switch 108 continues to pass a current. According to this example, the operating state of the current consumption unit 106 can be appropriately displayed.

  Here, in the modified example of the present invention, the current consumption unit 106 may consume the current according to the configuration necessary for the operation of the printing apparatus 10 instead of simply consuming the current by the resistance. For example, the current consumption unit 106 may include a heater as a configuration that consumes current. In this case, the current consumption unit 106 heats the medium 50 (see FIG. 1) with heat generated by the heater in accordance with consumption of current received through the switch 108. For example, when ultraviolet irradiation type ink is used in the printing apparatus 10, the current consumption unit 106 is configured to consume current, for example, a charger that charges current received via a switch, and ultraviolet rays to the ink. You may have a light source. In this case, the current consumption unit 106 cures the ink with, for example, ultraviolet rays generated by the light source according to the consumption of the current charged in the charger.

  If comprised in this way, the electric power consumed in the current consumption part 106 can be utilized effectively. The power consumption by the current consumption unit 106 may be used as part of the power consumption of the heater or the light source, for example. In this case, at a timing when no current flows to the current consumption unit, the heater or the light source may operate according to the power received from another power source, for example.

  FIG. 4 is a waveform diagram showing an example of the operation of the voltage control unit 20. In the printing apparatus 10, the main circuit board 18 causes the print head 12 to perform a scanning operation by causing the motor 16 to repeatedly drive and stop. Therefore, the motor speed waveform is a waveform in which a deceleration operation is performed at regular intervals.

  Further, the voltage of the motor power supply node 110 that is the power supply voltage output from the voltage control unit 20 to the main circuit board 18 is affected by the counter electromotive force during the deceleration operation of the motor 16. Therefore, for example, if current consumption by the current consumption unit 106 is not performed, the power supply voltage rises as indicated by the hatched portion 402 in the waveform.

  On the other hand, in this example, when the back electromotive force of the motor 16 is generated, the voltage rise detection unit 104 sets the gate voltage of the MOSFET Q1 constituting the switch 108 to H level and turns on the switch 108. In response to this, the current consumption unit 106 consumes current. Thereby, the rise of the power supply voltage is suppressed to the portion excluding the shaded portion 402 in the waveform.

  Therefore, according to this example, for example, the influence of the counter electromotive force of the motor 16 can be appropriately suppressed, and the voltage increase due to the counter electromotive force can be appropriately suppressed below a certain level. This can also prevent malfunction of the circuit due to a rise in power supply voltage and overvoltage of the control element.

  FIG. 5 is a circuit diagram showing a second example of the configuration of the voltage control unit 20. Except for the points described below, in FIG. 5, the configurations denoted by the same reference numerals as those in FIG. 2 are the same as or similar to the configurations in FIG. 2. In this example, the voltage rise detection unit 104 includes an analog-digital conversion circuit (ADC) 156, a CPU 152, and a plurality of resistors R21 and R22.

  The analog-digital conversion circuit 156 is, for example, a circuit that converts an input analog signal into a logic signal indicating the voltage of the analog signal. In this example, the analog-to-digital conversion circuit 156 receives the voltage of the motor power supply node 110 divided by the plurality of resistors R21 and R22, and converts it into a corresponding digital signal. As a result, the analog-digital conversion circuit 156 outputs a digital signal indicating the voltage of the node 110 between the motor power supplies.

  The CPU 152 receives the digital signal converted by the analog-digital conversion circuit 156, and detects the voltage of the motor power supply node 110 based on the digital signal. Then, the CPU 152 compares the reference voltage set by a program such as firmware with the voltage of the motor power supply node 110. In addition, by outputting an output signal corresponding to the comparison result to the switch 108, the opening and closing of the switch 108 is controlled according to the comparison result.

  For example, when determining that the voltage of the motor power supply node 110 is lower than the reference voltage, the CPU 152 outputs the L signal to the switch 108 to close the switch 108. When the CPU 152 determines that the voltage of the motor power supply node 110 is higher than the reference voltage, the CPU 152 opens the switch 108 by changing the output signal. As a result, the CPU 152 causes a current to flow through the switch 108 when the voltage of the motor power supply node 110 increases.

  Also in this example, for example, the CPU 152 can be used to appropriately detect the voltage of the motor power supply node 110. In addition, this makes it possible to flexibly set a reference voltage serving as a reference for detecting an increase in the voltage of the motor power supply node 110 with a high degree of freedom by a program such as firmware.

  In this example, the digital signal output from the analog-to-digital conversion circuit 156 indicates a voltage at a certain ratio with respect to the voltage of the motor power supply node 110 according to the division ratio by the plurality of resistors R21 and R22. Yes. Therefore, the analog-digital conversion circuit 156 does not directly indicate the voltage of the motor power supply node 110 but outputs a digital signal that indirectly indicates the voltage of the motor power supply node 110 by the divided voltage. Further, the CPU 152 compares the voltages in consideration of the division ratio, for example. The analog-to-digital conversion circuit 156 may output a digital signal directly indicating the voltage of the motor power supply node 110, for example, by receiving the voltage of the motor power supply node 110 as an input analog signal.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  The present invention can be suitably used for a printing apparatus, for example.

1 is a diagram illustrating an example of a configuration of a printing apparatus 10 according to an embodiment of the present invention. 3 is a circuit diagram illustrating a first example of a configuration of a voltage control unit 20. FIG. 3 is a diagram illustrating an example of a configuration of a current consumption unit 106. FIG. 4 is a waveform diagram showing an example of the operation of the voltage control unit 20. FIG. 3 is a circuit diagram showing a second example of the configuration of the voltage control unit 20. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Printing apparatus, 12 ... Print head, 14 ... Carriage, 16 ... Motor, 18 ... Main circuit board, 20 ... Voltage control part, 22 ... Constant voltage power supply, DESCRIPTION OF SYMBOLS 50 ... Medium, 102 ... Connection part, 104 ... Voltage rise detection part, 106 ... Current consumption part, 108 ... Switch, 110 ... Node between motor power supplies, 152 ... CPU 154... Digital-to-analog conversion circuit, 156... Analog-to-digital conversion circuit, 302... Resistance section, 304... Lighting display section, 402.

Claims (6)

A printing device that performs printing,
A print head;
A carriage for moving the print head;
A motor for powering the carriage;
A voltage control unit for controlling the voltage of power supplied from the constant voltage power source to the motor,
The voltage controller is
A voltage rise detection unit for detecting that the voltage of a node between motor power supplies, which is a node between the constant voltage power supply and the motor, rises higher than the output voltage of the constant voltage power supply;
It is provided in a path separate from the path connecting the constant voltage power supply and the motor, and the voltage of the node between the motor power supplies is changed to the output of the constant voltage power supply by opening and closing according to the output of the voltage rise detection unit. A switch that allows current to flow when it rises above the voltage,
A current consuming unit that consumes the current when the switch passes a current;
The voltage rise detector is
Printing having a CPU that operates according to an operation control program and uses a reference voltage preset by the program as a reference voltage for detecting an increase in the voltage between the motor power supply nodes apparatus. The voltage rise detector is
A digital-analog conversion circuit that converts an input digital signal into an analog signal;
A comparator that compares the voltage of the node between the motor power supplies and the voltage of the analog signal converted by the digital-analog conversion circuit;
The CPU outputs the digital signal designating the reference voltage to the digital-analog conversion circuit according to the program,
2. The switch according to claim 1, wherein the switch opens and closes according to the output of the comparator, and causes a current to flow when the voltage of the node between the motor power supplies rises higher than the output voltage of the constant voltage power supply. Printing device. The voltage rise detector is
An analog-to-digital conversion circuit that outputs a digital signal indicating the voltage of the motor power supply node based on the voltage of the motor power supply node;
The CPU outputs an output signal for controlling the opening and closing of the switch, and detects the voltage of the motor power supply node by receiving the digital signal from the analog-digital conversion circuit, and the voltage of the motor power supply node 2. The printing apparatus according to claim 1, wherein when the output voltage is determined to be higher than the reference voltage, the switch is opened by changing the output signal, and a current is passed through the switch.   The current consumption unit includes a heater, and heats a medium used in the printing apparatus by heat generated by the heater according to consumption of current received through the switch. 4. The printing apparatus according to any one of 3. The printing apparatus is a printing apparatus using an ultraviolet irradiation type ink that is cured by irradiation with ultraviolet rays.
The current consuming unit includes a charger that charges current received through the switch, and a light source that irradiates ultraviolet rays to the ink on a medium used in the printing apparatus, and the current charged in the charger. The printing apparatus according to claim 1, wherein the ink is cured by ultraviolet rays generated by the light source according to consumption. A voltage control device for controlling the voltage of power supplied from a constant voltage power source to a motor,
A voltage rise detection unit for detecting that the voltage of a node between motor power supplies, which is a node between the constant voltage power supply and the motor, rises higher than the output voltage of the constant voltage power supply;
It is provided in a path separate from the path connecting the constant voltage power supply and the motor, and the voltage of the node between the motor power supplies is changed to the output of the constant voltage power supply by opening and closing according to the output of the voltage rise detection unit. A switch that allows current to flow when it rises above the voltage,
A current consuming unit that consumes the current when the switch passes a current;
The voltage rise detector is
A voltage having a CPU that operates according to an operation control program and uses a reference voltage preset by the program as a reference voltage for detecting an increase in the voltage of the motor power supply node. Control device.

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