Printing device

Abstract

The present invention provides a printing device that can be easily miniaturized even when any one of multiple voltages is supplied from an external power supply having multiple voltages that can be supplied. The printing device includes a print head, a battery, and a USB PD controller. The printing device is connected to the external power supply via a connection that complies with the USB PD standard. The external power supply has multiple power profiles. The printing device uses either the external power supply or the battery as the power supply source for the print head to print. The printing device obtains the power supply voltage value of the power profile via the USB PD controller. The printing device compares the power supply voltage value with the rated voltage value of the print head. When the power supply voltage value of the power profile exceeds the rated voltage value of the print head (S13: Yes), the printing device uses the battery as the power supply source (S41). When the power supply voltage value of the power profile is less than the rated voltage value of the print head (S13: No), the printing device uses the external power supply as the power supply source (S21).

Description

Technical Field

[0001] The present invention relates to a printing device. Background Art

[0002] The peripheral device (printer) described in Patent Document 1 includes a USB (Universal Serial Bus) interface, a battery, a printing mechanism, and a power supply line. The peripheral device can be connected to a host computer (external power source) via the USB interface. The battery is chargeable and dischargeable and is connected to the USB interface via the power supply line. The printing mechanism is capable of printing on cut sheets and is connected to the USB interface via the power supply line. The peripheral device charges the battery and prints via power from the external power source.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-99361 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] For example, in power supply based on USB PD (USB Power Delivery), there are cases where an external power supply has multiple voltages that can be supplied, and one of these voltages is set and supplied to a peripheral device. In this case, in order to charge the battery, a voltage exceeding the rated voltage of the printing mechanism may be set and supplied to the peripheral device. To prevent the peripheral device from supplying a voltage exceeding the rated voltage to the printing mechanism, a step-down circuit is required in the power supply line between the USB interface and the printing mechanism to reduce the voltage supplied from the external power supply. This makes it difficult to miniaturize the peripheral device.

[0008] An object of the present invention is to provide a printing apparatus that can be easily miniaturized even when any one of a plurality of voltages is supplied from an external power supply having a plurality of supplyable voltages.

[0009] Technical solutions to problems

[0010] The printing device involved in the present invention can be connected to an external power supply, and the external power supply outputs power corresponding to any one of a plurality of voltage values, and is characterized in that it comprises: an acquisition unit, which acquires the plurality of voltage values ​​from the external power supply; a setting unit, which sets the size of the power supply power output by the external power supply based on the plurality of voltage values ​​acquired by the acquisition unit; a print head, which has a specified rated voltage value, uses either the external power supply or a battery charged by the power supply power as a power supply source, and uses the power supplied from the power supply source to print on a printing medium; and a control unit, which acquires the voltage value, i.e., the power supply voltage value, in the power supply power set by the setting unit, and compares the power supply voltage value with the rated voltage value. When the power supply voltage value exceeds the rated voltage value, the control unit sets the power supply source to the battery. When the power supply voltage value is below the rated voltage value, the control unit sets the power supply source to the external power supply.

[0011] With this configuration, when the external power supply supplies a voltage exceeding the rated voltage, the printer uses a battery as its power supply source. This eliminates the need for a step-down circuit to reduce the voltage supplied from the external power supply. Consequently, even when the printer is supplied with any of multiple voltages from an external power supply capable of supplying multiple voltages, the printer can be easily miniaturized.

[0012] In the present invention, the battery may be detachably mounted in the printing device, and the control unit may determine whether the battery is mounted. If the control unit determines that the battery is not mounted, the control unit may set the power supply source to the external power supply, even if the power supply voltage exceeds the rated voltage, and the setting unit may set the power supply voltage to be below the rated voltage. In this manner, even if the power supply voltage exceeds the rated voltage, the printing device may still print using the external power supply as the power supply source, even if the power supply voltage exceeds the rated voltage.

[0013] In the present invention, the printing device may further include a detection unit that detects the voltage of the battery. During printing by the print head using the battery as the power supply source, the control unit determines whether the battery needs to be charged based on the detection result of the detection unit. If charging of the battery is necessary, the control unit suspends printing by the print head and charges the battery using power supplied from the external power supply. In this manner, if charging of the battery is necessary during printing, the printing device suspends printing to charge the battery, thereby preventing printing failures caused by insufficient power supply from the battery.

[0014] In the present invention, the printing device may further include: a detection unit for detecting the battery voltage; and an input unit for instructing the print head to print. When the battery is the power supply source, the control unit determines whether the battery needs to be charged based on the detection result of the detection unit. If charging of the battery is necessary, the control unit charges the battery using power supplied by the external power source. If the input unit instructs the control unit to do so during battery charging, the control unit suspends battery charging and executes printing by the print head. In this manner, when the input unit instructs the print head to start printing while the battery is charging, the printing device suspends battery charging and starts printing. Therefore, the printing device can print at the timing desired by the user.

[0015] In the present invention, the printing device may further include a USB port that is connected to the external power source in accordance with the USB (Universal Serial Bus) standard, and the print head and the battery are supplied with power from the external power source via the USB port. In this case, the printing device can be connected to various external devices via the USB port, thereby improving convenience.

[0016] The printing device involved in the present invention can be connected to an external power supply, and the external power supply outputs power corresponding to any one of a plurality of voltage values, and is characterized in that it comprises: a print head for printing on a printing medium; a battery arranged in a detachable manner and capable of being charged and discharged; a first line for transmitting the power discharged by the battery to the print head; a first switch for switching the start and stop of power transmission of the first line; a USB port for connecting to the external power supply in accordance with the USB (Universal Serial Bus) standard to relay the power supplied from the external power supply; a second line for transmitting the power relayed by the USB port to the print head; a second switch for switching the start and stop of power transmission of the second line; a third line for transmitting the power relayed by the USB port to the battery; a setting unit for setting the size of the power output by the external power supply; and a first control unit for switching the first switch and the second switch based on the voltage value of the power set by the setting unit.

[0017] According to the above configuration, the printing device can change the power supply source for the print head by switching the first switch and the second switch via the first control unit. The first control unit switches the first switch and the second switch based on the voltage value of the power supply set by the setting unit. As a result, even when the voltage supplied by the external power supply is high, the printing device does not supply power to the print head via the second line. Therefore, the printing device does not need to provide a circuit to reduce the voltage on the second line. Therefore, even when any of multiple voltages are supplied from an external power supply with multiple voltages, the printing device can be easily miniaturized.

[0018] In the present invention, the second cable can be directly connected to the USB port and the print head, and the power relayed by the USB port is directly transmitted to the print head. In this way, the second cable is directly connected to the USB port and the print head, and the power relayed by the USB port is directly transmitted to the print head. This facilitates miniaturization of the printing device.

[0019] In the present invention, the printer may further include a third switch for switching between starting and stopping power transmission on the third line; and a second control unit for switching the third switch based on the voltage value set by the setting unit. In this case, the printer switches between starting and stopping battery charging by the second control unit switching the third switch. This allows the printer to prevent malfunctions caused by excessive power supply to the battery, such as battery overvoltage.

[0020] In the present invention, the printing device may further include a fourth switch on the second and third lines, which switches between starting and stopping power relaying at the USB port, and a third control unit that switches the fourth switch. In this case, the printing device can prevent unintended power from being delivered to the print head or battery by switching between starting and stopping power relaying at the USB port. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a diagram showing the electrical system of the printing apparatus 1 .

[0022] Figure 2 This is a block diagram showing the electrical configuration of the printing apparatus 1 .

[0023] Figure 3 This diagram shows the relationship between the power profile of the external power source 99 and whether the printing device 1 can print and whether the battery 71 can be charged.

[0024] Figure 4 This is a flowchart of the printing process executed by the CPU 51 .

[0025] Figure 5 This is a flowchart of the printing process executed by the CPU 51 .

[0026] Figure 6 This is a flowchart of the power source determination process executed by the CPU 81 . DETAILED DESCRIPTION

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The accompanying drawings are used to illustrate the technical features that can be adopted by the present invention. The structures of the devices described in the accompanying drawings are not intended to be limiting, but are merely illustrative examples.

[0028] Printing device 1 is a thermal transfer printer driven by power supplied from either external power supply 99 or battery 71. Printing device 1 can print characters (objects such as letters, symbols, numbers, and graphics) on a print medium (eg, a thermal label).

[0029] Reference Figure 1 The structure of the printing device 1 is described below. The printing device 1 includes a housing 2. An input unit 5 and a USB connector 91 are provided on the surface of the housing 2. The input unit 5 can receive user operations. The USB connector 91 is a connection port for connecting to a USB device such as an external power supply 99 via a cable 98 that complies with the USB PD (Power Delivery) standard.

[0030] The external power supply 99 is, for example, a general-purpose personal computer, a mobile terminal, a tablet terminal, etc. The external power supply 99 has a plurality of power profiles based on the power rules in the USB PD standard (see Figure 3 Each power profile corresponds to a specified power and voltage (hereinafter referred to as a power voltage value) that the external power supply 99 can output. The power voltage values ​​corresponding to the power profiles of the external power supply 99 in this embodiment are 5V, 9V, 15V, and 20V. The external power supply 99 can output power (voltage level: power voltage value) corresponding to any of the multiple power profiles to the printing device 1. The USB connector 91 relays the power supplied from the external power supply 99 (hereinafter referred to as power supply power).

[0031] Inside the housing 2 are located the mounting unit 3, the print head 21, the first cable 36, the second cable 37, the third cable 38, the drive circuits 31 and 33, the charging circuit 61, the control unit 50, and the USB PD controller 80. The mounting unit 3 allows for the detachable installation of a battery 71. Battery 71 is, for example, a lithium-ion battery or an electric double-layer capacitor. In this embodiment, the fully charged voltage of battery 71 is 8.4V.

[0032] The print head 21 generates heat using power supplied from either the external power supply 99 or the battery 71 , thereby enabling printing on a print medium. The print head 21 has a predetermined rated voltage value. In this embodiment, the rated voltage value of the print head 21 is 9V.

[0033] The first line 36 is connected to the battery 71 mounted on the mounting portion 3 and the print head 21. The first line 36 transmits the power (maximum voltage 8.4V) discharged by the battery 71 to the print head 21. The first line 36 does not include a voltage-dropping circuit for reducing the voltage transmitted from the battery 71 to the print head 21. Therefore, the voltage in the first line 36 does not drop, except for a slight voltage drop caused by resistors and other components used for circuit protection. Hereinafter, the absence of a voltage-dropping circuit in the power supply path for reducing the transmitted voltage is referred to as a direct connection.

[0034] The first line 36 is provided with a drive circuit 33. The drive circuit 33 is an electronic circuit for controlling the drive of the print head 21. The drive circuit 33 includes a FET 34 as a switching element. The FET 34 switches between an on state and an off state based on an instruction output from the control unit 50. When the FET 34 is in the on state, the first line 36 transmits power from the battery 71 to the print head 21. When the FET 34 is in the off state, the first line 36 stops transmitting power from the battery 71 to the print head 21.

[0035] The third line 38 is directly connected to the battery 71 and USB connector 91 mounted on the mounting portion 3. The third line 38 transmits the power relayed by the USB connector 91 to the battery 71 mounted on the mounting portion 3. The voltage on the third line 38 does not drop except for a slight voltage drop caused by a resistor element used for circuit protection.

[0036] A charging circuit 61 is provided on the third line 38. The charging circuit 61 is an electronic circuit for controlling the charging of the battery 71. The charging circuit 61 includes a FET 62, which serves as a switching element. The FET 62 switches between an on and off state based on instructions from the control unit 50. When the FET 62 is on, the third line 38 transmits power from the USB connector 91 to the battery 71. When the FET 62 is off, the third line 38 stops transmitting power from the USB connector 91 to the battery 71.

[0037] The second line 37 is directly connected to the print head 21 and the USB connector 91. The second line 37 transmits the power relayed by the USB connector 91 to the print head 21. In the second line 37, the voltage does not drop except for a slight voltage drop caused by a resistor element for circuit protection.

[0038] The second line 37 is provided with a drive circuit 31. Like the drive circuit 33, the drive circuit 31 is an electronic circuit for controlling the drive of the print head 21. The drive circuit 31 includes a FET 32 as a switching element. The FET 32 switches between an on state and an off state based on an instruction output from the control unit 50. When the FET 32 is in the on state, the second line 37 transmits power from the USB connector 91 to the print head 21. When the FET 32 is in the off state, the second line 37 stops transmitting power from the USB connector 91 to the print head 21.

[0039] A switch 35 is provided on the second line 37 and the third line 38. The switch 35 switches between an on state and an off state according to an instruction outputted from the USB PD controller 80. When the switch 35 is in the on state, the power relayed by the USB connector 91 is supplied to the drive circuit 31 and the charging circuit 61. When the switch 35 is in the off state, the power relayed by the USB connector 91 is stopped from being supplied to the drive circuit 31 and the charging circuit 61.

[0040] The control unit 50 controls the printing apparatus 1 as a whole. The control unit 50 communicates with the USB PD controller 80 to control the USB PD controller 80. The USB PD controller 80 sends the control result to the control unit 50. The control unit 50 feeds back the control result received from the USB PD controller 80 to control the FETs 32, 34, 62, etc.

[0041] Reference Figure 2 , the electrical structure of the printing device 1 is described. The control unit 50 includes a CPU 51, a ROM 52, a RAM 53, a flash memory 54, and an input / output interface (hereinafter referred to as an I / O I / F) 59. The ROM 52, RAM 53, flash memory 54, and I / O I / F 59 are electrically connected to the CPU 51.

[0042] The CPU 51 executes various programs for controlling the printing apparatus 1. The ROM 52 stores various programs, etc. The RAM 53 temporarily stores flags, counters, calculation results, etc. The flash memory 54 stores various settings, etc. of the printing apparatus 1.

[0043] The printer 1 also includes a voltage detection unit 73. The voltage detection unit 73 detects the voltage of the battery 71. The voltage detection unit 73 is electrically connected to the CPU 51 via the input / output interface 59. The battery 71 is provided with a thermistor 72 for detecting the temperature of the battery 71. The thermistor 72 is electrically connected to the CPU 51 via the input / output interface 59. The input unit 5 inputs various instructions to the control unit 50 in response to user operations.

[0044] The CPU 51 controls the charging of the battery 71 by controlling the charging circuit 61. The printing apparatus 1 does not simultaneously charge the battery 71 and print with the print head 21. When charging the battery 71, the CPU 51 turns on the FET 62 and turns off the FETs 32 and 34.

[0045] The CPU 51 controls the FETs 32 and 34 so that either the first line 36 or the second line 37 transmits power to the print head 21. When the first line 36 transmits power to the print head 21, the power supply source for the print head 21 is the battery 71. In this case, the CPU 51 turns on the FET 34 and turns off the FETs 32 and 62. When the second line 37 transmits power to the print head 21, the power supply source for the print head 21 is the external power supply 99. In this case, the CPU 51 turns on the FET 32 and turns off the FETs 34 and 62.

[0046] The USB PD controller 80 is electrically connected to the CPU 51 via the input / output I / F 59 and to the external power supply 99 via the USB connector 91. The USB PD controller 80 controls the switch 35 and communicates with the external power supply 99 based on instructions output by the CPU 51. The USB PD controller 80 includes a CPU 81 and a ROM 82. The CPU 81 executes various programs stored in the ROM 82.

[0047] Reference Figure 3 The following describes an overview of control of the printing device 1. When the USB connector 91 is connected to the external power supply 99, the CPU 81 communicates with the external power supply 99 and obtains multiple power profiles from the external power supply 99. The CPU 81 selects one of the obtained power profiles and outputs the selected power profile to the CPU 51 and the external power supply 99. The external power supply 99 then outputs power corresponding to the selected power profile.

[0048] For example, when the external power supply 99 has Figure 3 In the case of the power profiles of profiles No. 1 to No. 5 shown, CPU 81 selects the power profile of profile No. 3. CPU 51 obtains the power supply voltage value (15V) of profile No. 3 from CPU 81. The power supply voltage value of profile No. 3 is greater than the rated voltage value (9V) of the print head 21. CPU 51 does not transmit power on the second line 37, but transmits power supply power to the battery 71 through the third line 38. The battery 71 is charged by the power supply power. CPU 51 sets the power supply source of the print head 21 to the battery 71. When printing, CPU 51 turns on FET 34 and turns off FETs 32 and 62. Charging of the battery 71 is stopped, and printing is performed by the print head 21.

[0049] The voltage of the battery 71 may drop due to the print head 21, and the battery 71 may need to be charged. In this case, the CPU 51 turns on the FET 62 and turns off the FETs 32 and 34. When the print head 21 is printing, printing is stopped and the battery 71 is charged.

[0050] For example, when the external power supply 99 has Figure 3 In the case of power profiles 1 and 2 shown in the figure, CPU 81 selects power profile 2. CPU 51 obtains the power supply voltage value (9V) for profile 2 from CPU 81. The power supply voltage value for profile 2 is below the rated voltage of print head 21. CPU 51 sets the power supply source for print head 21 to external power supply 99. CPU 51 does not transmit power via third line 38, but instead transmits power to print head 21 via second line 37. Battery 71 is not charged. During printing, CPU 51 turns on FET 32 and turns off FETs 34 and 62.

[0051] The battery 71 may not be installed in the printing device 1. The CPU 51 determines whether the battery 71 is installed based on the electrical connection with the thermistor 72. For example, when the external power supply 99 has Figure 3In the case of the power profiles No. 1 to No. 5 shown, if the power corresponding to the power profiles No. 3 to No. 5 is supplied from the external power supply 99 , the print head 21 may malfunction.

[0052] If the CPU 51 determines that the battery 71 is not installed, it outputs an instruction to the CPU 81. In response to the instruction from the CPU 51, the CPU 81 selects the power profile of profile number 2. The CPU 51 sets the power supply source for the print head 21 to the external power supply 99. The CPU 51 does not transmit power via the third line 38, but instead transmits power from the power source to the print head 21 via the second line 37. During printing, the CPU 51 turns on the FET 32 and turns off the FETs 34 and 62.

[0053] refer to Figure 4 and Figure 5 Next, the printing process executed by the CPU 51 will be described. The printing process is a process for determining the power supply source of the print head 21 and executing printing by the print head 21. When the printing process starts, the FETs 32, 34, and 62 are all in the OFF state, and the switch 35 is in the OFF state.

[0054] When the USB connector 91 is connected to the external power supply 99, the CPU 51 reads the program stored in the ROM 52 and executes the printing process. The CPU 81 reads the program stored in the ROM 82 in parallel with the printing process executed by the CPU 51 and executes the power supply determination process described later (see Figure 6 ).

[0055] like Figure 4 As shown, when the printing process starts, the CPU 51 outputs a power selection instruction to the CPU 81 (S11). The CPU 81 that receives the power selection instruction performs a power source power determination process (see Figure 6 ), communicates with the external power supply 99 to select and determine a power profile. When the power profile is determined, the CPU 81 outputs a power determination instruction to the CPU 51. The power determination instruction includes information on the power supply voltage value corresponding to the power profile determined by the CPU 81.

[0056] The CPU 51 determines whether it has received a power determination instruction from the CPU 81 (S12). If it determines that it has not received a power determination instruction from the CPU 81 (S12: No), the CPU 51 waits for processing. If it determines that it has received a power determination instruction from the CPU 81 (S12: Yes), the CPU 51 determines, based on the power determination instruction, whether the power supply voltage value of the determined power profile exceeds the rated voltage value of the print head 21 (S13). If it determines that the power supply voltage value of the determined power profile is less than the rated voltage value of the print head 21 (S13: No), the CPU 51 transfers processing to S21.

[0057] If the power supply voltage value of the determined power profile exceeds the rated voltage value of the print head 21 (S13: YES), the CPU 51 determines whether the battery 71 is installed in the mounting unit 3 (S14). In S14, the CPU 51 makes this determination based on whether an electrical connection with the thermistor 72 exists. If an electrical connection with the thermistor 72 exists and the battery 71 is installed in the mounting unit 3 (S14: YES), the CPU 51 determines that the battery 71 is installed in the mounting unit 3 (S41).

[0058] If there is no electrical connection to the thermistor 72 and the battery 71 is determined not to be installed in the installation unit 3 (S14: No), the CPU 51 outputs a power change instruction to the CPU 81 (S15). Upon receiving the power selection instruction, the CPU 81 changes the power profile determined in the power source determination process to a power profile with a power source voltage value that is less than the rated voltage of the print head 21. The CPU 51 then proceeds to S21.

[0059] If the power supply voltage value in the determined power profile is less than or equal to the rated voltage value of the print head 21 (S13: No), or if the battery 71 is not installed in the mounting unit 3 (S14: No), the CPU 51 determines that the power supply source for the print head 21 is the external power supply 99 (S21). In this case, the power supply voltage value in the determined power profile is less than or equal to the rated voltage value of the print head 21. The CPU 51 outputs a power reception start instruction to the CPU 81 (S22). Upon receiving the power reception start instruction, the CPU 81 switches the switch 35 to the on state during the power supply determination process. The printing device 1 begins receiving power from the external power supply 99.

[0060] The CPU 51 determines whether a print instruction has been received from the input unit 5 (S31). When printing is performed by the print head 21, the user operates the input unit 5. The input unit 5 outputs a print instruction to the CPU 51. If it determines that no print instruction has been received (S31: No), the CPU 51 waits for processing.

[0061] If it is determined that a print instruction has been received (S31: YES), the CPU 51 executes power-driven printing (S32). When executing power-driven printing, the CPU 51 turns on the FET 32. Power transmission via the second line 37 begins, and power is supplied from the external power supply 99 to the print head 21. The CPU 51 controls the drive of the print head 21 via the drive circuit 31 to perform printing. After executing power-driven printing, the CPU 51 returns the process to S31. The CPU 51 waits until a print instruction is received, and in response to receipt of the print instruction, executes power-driven printing (S31, S32).

[0062] After deciding that the power supply source is the battery 71 (S41), the CPU 51 outputs a power reception start instruction to the CPU 81 (S42). S42 is the same process as S22. The CPU 81 switches the switch 35 to the on state. The printing device 1 starts receiving power from the external power supply 99. The CPU 51 transfers the process to S43 (refer to Figure 5 ).

[0063] like Figure 5 As shown, the CPU 51 determines whether the voltage of the battery 71 is less than the full charge voltage (8.4V) based on the detection result of the voltage detection unit 73 (S43). If the voltage of the battery 71 is determined to be less than the full charge voltage (S43: Yes), the CPU 51 switches the FET 62 to the on state and starts charging the battery 71 (S51). The CPU 51 determines whether a print instruction has been received from the input unit 5 (S52). S52 is the same process as S31. If the CPU 51 determines that a print instruction has not been received (S52: No), the CPU 51 returns the process to S43.

[0064] If the CPU 51 determines that a print instruction has been received (S52: YES), it switches the FET 62 to the OFF state, stopping charging of the battery 71 (S53). The CPU 51 starts battery-powered printing (S61). When battery-powered printing begins, the CPU 51 turns the FET 34 to the ON state. Power transmission via the first line 36 begins, and power is supplied from the battery 71 to the print head 21. The CPU 51 controls the drive of the print head 21 via the drive circuit 33, and printing begins.

[0065] Based on the detection results of the voltage detection unit 73, the CPU 51 determines whether the voltage of the battery 71 is less than a predetermined limit voltage during printing (S62). The limit voltage is the lower limit of the voltage required to drive the print head 21. If the voltage of the battery 71 is determined to be above the limit voltage (S62: No), the CPU 51 determines whether printing on the print medium is complete (S63). If the printing is determined to be incomplete (S63: No), the CPU 51 returns the process to S62. The CPU 51 repeats S62 and S63 until printing on the print medium is complete.

[0066] If the CPU 51 determines that printing is complete (S63: YES), it terminates battery-powered printing (S64). When battery-powered printing is complete, the CPU 51 turns off the FET 34. Power supply to the print head 21 via the first line 36 is terminated. The CPU 51 returns the process to S43.

[0067] If the voltage of the battery 71 is determined to be less than the limit voltage during printing (S62: YES), the CPU 51 stops battery-powered printing (S91). When battery-powered printing stops, the CPU 51 turns off the FET 34. Power supply to the print head 21 via the first line 36 ends. Similar to S51, the CPU 51 turns on the FET 62 and begins charging the battery 71 (S92).

[0068] Based on the detection result of the voltage detection unit 73, the CPU 51 determines whether the voltage of the battery 71 is greater than or equal to a constant n times the limit voltage (S93). The constant n is a predetermined number greater than 1 and is set so that n times the limit voltage is less than the full charge voltage. If the voltage of the battery 71 is determined to be less than n times the limit voltage (S93: No), the CPU 51 waits for processing and continues charging the battery 71. If the voltage of the battery 71 is determined to be greater than or equal to n times the limit voltage (S93: Yes), the CPU 51 transfers the processing to S53. The CPU 51 switches the FET 62 to the off state, stops charging the battery 71 (S53), and resumes the battery-driven printing that was stopped (S61).

[0069] If the voltage of the battery 71 is determined to be at the fully charged voltage (S43: No), the CPU 51 switches the FET 62 to the off state (S71). If the battery 71 is overcharged, charging is terminated. Even if the voltage of the battery 71 is at the fully charged voltage at the start of printing, the CPU 51 executes S71. The CPU 51 determines whether a print instruction has been received from the input unit 5 (S72). S72 is the same process as S31. If the print instruction has not been received (S72: No), the CPU 51 returns the process to S43.

[0070] If the CPU 51 determines that a print instruction has been received (S72: YES), it starts battery-powered printing (S81). S81 is the same process as S61. When battery-powered printing begins, the CPU 51 turns on the FET 34. Power transmission via the first line 36 begins, and power is supplied from the battery 71 to the print head 21. The CPU 51 controls the drive of the print head 21 via the drive circuit 33, and printing on the print medium begins.

[0071] S82 to S84 are the same processes as S62 to S64 and will be briefly described. The CPU 51 determines whether the voltage of the battery 71 is less than the limit voltage during printing (S82). If the voltage of the battery 71 is determined to be less than the limit voltage (S82: Yes), the CPU 51 transfers the process to S91. If the voltage of the battery 71 is determined to be greater than the limit voltage (S82: No), the CPU 51 determines whether printing on the print medium is complete (S83). If the printing is determined to be incomplete (S83: No), the CPU 51 returns the process to S82. If the printing is determined to be complete (S83: Yes), the CPU 51 ends the battery-powered printing (S84). The CPU 51 turns off the FET 34. Power supply to the print head 21 via the first line 36 is terminated. The CPU 51 returns the process to S43.

[0072] Reference Figure 6 , the power source power determination process executed by the CPU 81 will be described. The power source power determination process is a process for determining the power source power and receiving power from the external power source 99. The power source power determination process is similar to the printing process executed by the CPU 51 (see Figure 4 When the USB connector 91 is connected to the external power supply 99, the CPU 81 reads the program stored in the ROM 82 and executes the power source power determination process.

[0073] When the power source determination process starts, the CPU 81 determines whether it has received the power source determination process from the CPU 51 in S11 (see Figure 4) (S101). If it is determined that no power selection instruction has been received from the CPU 51 (S101: No), the CPU 81 waits for processing. If it is determined that a power selection instruction has been received from the CPU 51 (S101: Yes), the CPU 81 communicates with the external power supply 99 and obtains a plurality of power profiles held by the external power supply 99 (S102).

[0074] The CPU 81 selects and determines one of the multiple power profiles obtained (S103). In step S103, if the power supply voltage values ​​of the multiple power profiles obtained are all below 9V, the CPU 81 selects and determines the power profile with the highest power supply voltage value among the multiple power profiles. If the power supply voltage values ​​of any of the multiple power profiles obtained are greater than 9V, the CPU 81 selects and determines the power profile with the lowest power supply voltage value among the power profiles with power supply voltage values ​​greater than 9V. The CPU 81 outputs a power determination instruction including information about the power supply voltage value of the determined power profile to the CPU 51 (S104).

[0075] The CPU 81 determines whether the CPU 51 receives the data in S15 (see Figure 4 ) output in the power change instruction (S111). If it is determined that no power change instruction has been received from the CPU 51 (S111: No), the CPU 81 transfers the process to S121. If it is determined that a power change instruction has been received from the CPU 51 (S111: Yes), the CPU 81 executes the power change process (S112). In the power change process, the CPU 81 selects and determines the power profile with the largest power supply voltage value of 9V or less among the power profiles obtained in S102. The CPU 81 transfers the process to S121.

[0076] The CPU 81 determines whether the CPU 51 receives the signal received in S22 or S42 (see Figure 4) outputs a power reception start instruction (S121). When it is determined that the power reception start instruction has not been received from the CPU51 (S121: No), the CPU81 returns the process to S111. The CPU81 repeatedly executes S111 to S121 until the power reception start instruction is received from the CPU51. When it is determined that the power reception start instruction is received from the CPU51 (S121: Yes), the CPU81 outputs a power output instruction to the external power supply 99 (S122). The power output instruction includes information on the power profile determined by the CPU81. Based on the power determination instruction, the external power supply 99 outputs the power corresponding to the power profile determined by the CPU81. The CPU81 switches the switch 35 to the on state and starts receiving the power (S123). The CPU81 returns the process to S101.

[0077] As described above, the printing device 1 includes a print head 21, a battery 71, and a USB PD controller 80. The printing device 1 is connected to an external power supply 99 having multiple power profiles based on the USB PD standard. Each power profile corresponds to a predetermined power and power supply voltage value that the external power supply 99 can output. The external power supply 99 outputs power corresponding to one of the multiple power profiles as power supply power. The printing device 1 performs printing using either the external power supply 99 or the battery 71 as the power supply source for the print head 21. The CPU 81 of the USB PD controller 80 obtains multiple power profiles from the external power supply 99 (S102) and selects one of the multiple power profiles (S103). The CPU 51 of the control unit 50 compares the power supply voltage value of the power profile determined by the CPU 81 with the rated voltage value of the print head 21. If the power supply voltage value of the power profile exceeds the rated voltage value of the print head 21 (S13: YES), the printing device 1 selects the battery 71 as the power supply source (S41). When the power supply voltage value in the power profile is equal to or less than the rated voltage value of the print head 21 ( S13 : No), the printing apparatus 1 uses the external power supply 99 as the power supply source ( S21 ).

[0078] In this manner, when the external power supply 99 supplies a voltage exceeding the rated voltage, the printer 1 uses the battery 71 as the power supply source. Consequently, the printer 1 does not need to include a voltage-step-down circuit to reduce the voltage supplied from the external power supply 99. Consequently, even when the printer 1 is supplied with power from an external power supply 99 with multiple voltage levels, the printer 1 can be easily miniaturized.

[0079] In the printing device 1, the installation portion 3 installs the battery 71 in a detachable manner. The CPU 51 determines whether the battery 71 is installed in the installation portion 3 (S14). When it is determined that the battery 71 is not installed in the installation portion 3 (S14: No), the CPU 51 outputs a power change instruction to the CPU 81 (S15). The CPU 81 that receives the power selection instruction changes from the determined power profile to a power profile in which the power supply voltage value is less than the rated voltage value of the print head 21. The CPU 51 determines the power supply source of the print head 21 to be the external power supply 99 (S21). In this way, the printing device 1 has a situation where the battery 71 is not installed in the installation portion 3 and the power supply source of the print head 21 cannot be set to the battery 71. In this case, even if the power supply voltage value exceeds the rated voltage value, the CPU 51 can set the power supply source of the print head 21 to the external power supply 99 to perform printing.

[0080] The printing device 1 includes a voltage detection unit 73. When the battery 71 is the power source for the print head 21, the CPU 51 determines whether the voltage of the battery 71 is less than the limit voltage during printing (S62, S82). If the voltage of the battery 71 is determined to be less than the limit voltage (S62: Yes or S82: Yes), the CPU 51 determines that charging of the battery 71 is necessary, suspends printing (S91), and then starts charging the battery 71 (S92). In this way, when the voltage of the battery 71 is less than the limit voltage during printing and charging of the battery 71 is necessary, the printing device 1 suspends printing to charge the battery 71. Therefore, the printing device 1 can prevent printing failures caused by insufficient power from the battery 71 during printing.

[0081] The printing device 1 includes an input unit 5. When the power supply source for the print head 21 is a battery 71, the CPU 51 determines whether the voltage of the battery 71 is less than the fully charged voltage based on the detection result of the voltage detection unit 73 (S43). If it is determined that the voltage of the battery 71 is less than the fully charged voltage (S43: Yes), the CPU 51 starts charging the battery 71 (S51). While the battery 71 is charging, the CPU 51 determines whether a print instruction has been received from the input unit 5 (S52). If it is determined that a print instruction has been received (S52: Yes), the CPU 51 stops charging the battery 71 (S53) and starts printing (S61). In this way, when the CPU 51 receives a print start instruction from the input unit 5 while the battery 71 is charging, it stops charging the battery 71 and starts printing. Therefore, the printing device 1 can print at the time desired by the user.

[0082] The printing device 1 includes a USB connector 91 and is connected to an external power source 99 via a USB-compliant cable 98. The external power source 99 supplies power to the printing device 1 via the USB connector 91. In this case, the printing device 1 can be connected to various external devices via the USB connector 91, thereby improving convenience.

[0083] The printing device 1 is connected to an external power supply 99 having multiple power profiles based on the USB PD standard. Each power profile corresponds to a specified power and power supply voltage value that the external power supply 99 can output. The external power supply 99 outputs power corresponding to any of the multiple power profiles as power supply power. The printing device 1 includes a print head 21, a battery 71, a first line 36, a second line 37, a third line 38, FETs 32 and 34, a USB connector 91, a USB PD controller 80, and a control unit 50. The first line 36 transmits power discharged from the battery 71 to the print head 21. The FET 34 is provided on the first line 36 and switches the start and stop of power transmission on the first line 36. The second line 37 transmits power relayed by the USB connector 91 to the print head 21. The FET 32 is provided on the second line 37 and switches the start and stop of power transmission on the second line 37. The third line 38 transmits power relayed by the USB connector 91 to the battery 71. The USB PD controller 80 determines the amount of power output by the external power supply 99. The control unit 50 switches the FETs 32 and 34 based on the determined power supply voltage value of the power supply.

[0084] In this way, the printer 1 can change the power source for the print head 21 by switching the FETs 32 and 34 using the control unit 50. The control unit 50 switches the FETs 32 and 34 based on the power supply voltage value determined by the USB PD controller 80. Consequently, even when the voltage supplied from the external power supply 99 is high, the printer 1 does not transmit power to the print head 21 via the second line 37. Therefore, the printer 1 does not need a voltage-reducing circuit on the second line 37. Consequently, even when power is supplied from an external power supply 99 with multiple supply voltage values, the printer 1 can be easily miniaturized.

[0085] The second line 37 is directly connected to the print head 21 and the USB connector 91. Thus, no voltage-dropping circuit for dropping the voltage supplied from the USB connector 91 to the print head 21 is provided on the second line 37. Therefore, the printing apparatus 1 can be easily miniaturized.

[0086] The printer 1 includes a FET 62. The FET 62 is provided on the third line 38 and switches between starting and stopping power transmission on the third line 38. The control unit 50 switches the FET 62 based on the power supply voltage value determined by the USB PD controller 80. In this case, the control unit 50 switches between starting and stopping charging of the battery 71 by switching the FET 62. Consequently, the printer 1 can prevent malfunctions caused by excessive power supply to the battery 71, such as overvoltage in the battery 71.

[0087] Printing device 1 includes a switch 35. Switch 35 is provided on second line 37 and third line 38, and switches between starting and stopping the transmission of power relayed by USB connector 91 via second line 37 and third line 38. The USB PD controller 80 switches switch 35. In this case, by switching switch 35, printing device 1 can prevent unintended power from being delivered to print head 21 or battery 71.

[0088] In the above embodiment, the USB PD controller 80 corresponds to the "acquisition unit" and "setting unit" of the present invention. The voltage detection unit 73 corresponds to the "detection unit" of the present invention. The USB connector 91 corresponds to the "USB port" of the present invention. The FET 34 corresponds to the "first switch" of the present invention. The FET 32 corresponds to the "second switch" of the present invention. The control unit 50 corresponds to the "first control unit" and "second control unit" of the present invention. The FET 62 corresponds to the "third switch" of the present invention. The USB PD controller 80 corresponds to the "third control unit" of the present invention. The switch 35 corresponds to the "fourth switch" of the present invention.

[0089] The printing device of the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention. For example, the following modifications may be appropriately applied. The following modifications may also be appropriately combined.

[0090] The printer 1 may not include the mounting portion 3. In this case, the battery 71 may be built into the housing 2 and cannot be removed. The printer 1 may not include the switch 35. The switch that starts and stops the power supplied by the second and third wires 37 and 38 may be provided on the cable 98, for example. The switch 35 may also be switched by the control unit 50.

[0091] A step-down circuit for lowering the voltage being transmitted, or a step-up circuit for raising the voltage being transmitted may be provided on the first line 36 and the third line 38. Switches other than the FETs 32, 34, and 62 may also be provided on the first line 36, the second line 37, and the third line 38. The FETs 32, 34, and 62 are not limited to switching elements; for example, relay switches may also be provided.

[0092] Alternatively, a limit switch may be used to detect whether the battery 71 is mounted on the mounting portion 3. In this case, the CPU 51 may make the determination in S14 based on the detection result of the limit switch. The battery 71 may not include the thermistor 72.

[0093] The USB PD controller 80 can be either hardware or software. If the USB PD controller 80 is hardware, the power source determination process is performed by the CPU 51 controlling the USB PD controller 80. In this case, the control unit 50 corresponds to the "acquisition unit," "setting unit," or "third control unit" of the present invention.

[0094] The steps of each process in the printing device 1 are not limited to being executed by the CPU of each device; they may be partially or entirely executed by another electronic device (e.g., an ASIC). The steps of each process in the printing device 1 may also be distributed among multiple electronic devices (e.g., multiple CPUs). For example, a portion of the power source determination process may be executed by the CPU 51.

[0095] In the above embodiment, the printer 1 is connected to the external power source 99 via a connection conforming to the USB PD standard, but the present invention is not limited thereto. The printer 1 may also be connected to the external power source 99 via a connection conforming to USB BC (USB Battery Charge) or a connection other than the USB standard. When connected to the external power source 99 via a connection other than the USB standard, the printer 1 may not include the USB connector 91.

[0096] Programs containing instructions for CPUs 51 and 81 to execute processes can be stored in the storage device of each device in printing apparatus 1 before the program is executed. Therefore, the method and path for acquiring the program, as well as the device storing the program, can be modified as appropriate. Programs executed by printing apparatus 1 can also be received from other devices via a cable or wireless communication and stored in a storage device such as flash memory 54. Examples of these other devices include PCs and servers connected via a network.

[0097] The steps of each process of the printing device 1 may be changed in order, omitted, or added as needed. The operating system (OS) running on the printing device 1 and the like may perform part or all of the processing based on instructions from the CPU 51 or 81 of the printing device 1, which is also within the scope of this disclosure.

[0098] Label Description

[0099] 1 Printing device

[0100] 5 Input section

[0101] 21 print head

[0102] 32, 34, 62 FET

[0103] 35 Switch

[0104] 36 First Line

[0105] 37 Second Line

[0106] 38 Third Line

[0107] 50 Control Department

[0108] 51, 81CPU

[0109] 71 batteries

[0110] 73 Voltage detection unit

[0111] 80USB PD controller

[0112] 91USB connector.

Claims

1. A printing device capable of being connected to an external power supply, wherein the external power supply outputs power corresponding to any one of a plurality of voltage values. It is characterized in that have: an acquiring unit, configured to acquire the plurality of voltage values ​​from the external power supply; a setting unit configured to set a magnitude of the power output by the external power source based on the plurality of voltage values ​​acquired by the acquisition unit; a print head having a predetermined rated voltage value, using either the external power supply or a battery charged by the power of the power supply as a power supply source, and printing on a print medium using the power supplied from the power supply source; and Control Department, The control unit obtains the power supply voltage value, which is the voltage value of the power supply power set by the setting unit, and compares the power supply voltage value with the rated voltage value. When the power supply voltage value exceeds the rated voltage value, the control unit sets the power supply source to the battery, and when the power supply voltage value is equal to or less than the rated voltage value, the control unit sets the power supply source to the external power supply.

2. The printing device according to claim 1, wherein The battery is detachably mounted on the printing device. The control unit determines whether the battery is installed. When the control unit determines that the battery is not installed, Even when the power supply voltage value exceeds the rated voltage value, the control unit sets the power supply source to the external power supply, and The setting unit sets the power supply voltage value to be equal to or lower than the rated voltage value.

3. The printing device according to claim 1 or 2, characterized in that: The printing device further includes a detection unit that detects the voltage of the battery. During the execution of printing by the print head with the battery as the power supply source, the control unit determines whether the battery needs to be charged based on the detection result of the detection unit. If the battery needs to be charged, the control unit stops printing by the print head and charges the battery using the power supplied from the external power supply.

4. The printing device according to claim 1 or 2, characterized in that: The printing device further comprises: a detection unit for detecting the voltage of the battery; and an input unit for instructing printing by the print head, When the power supply source is the battery, the control unit determines whether the battery needs to be charged based on the detection result of the detection unit. When the battery needs to be charged, the control unit charges the battery using the power supplied from the external power supply. When an instruction is given from the input unit during charging of the battery, the control unit stops charging of the battery and executes printing by the print head.

5. The printing device according to claim 1 or 2, characterized in that: The printing device further includes a USB port, which is connected to the external power supply via a connection conforming to the USB standard. The print head and the battery are supplied with power from the external power source via the USB port.

6. A printing device capable of being connected to an external power supply, the external power supply outputting power corresponding to any one of a plurality of voltage values, It is characterized by: have: A print head, which prints on a print medium; The battery is arranged in a detachable manner and can be charged and discharged; a first line, transmitting the power discharged by the battery to the print head; a first switch for switching on and off power transmission of the first line; A USB port connected to the external power source via a connection conforming to the USB standard, and relaying power supplied from the external power source; a second line for delivering power relayed by the USB port to the print head; a second switch for switching on and off power transmission of the second line; a third line for delivering the power relayed by the USB port to the battery; a setting unit for setting the magnitude of the power output by the external power source; and The first control unit switches the first switch and the second switch based on the voltage value of the power supply set by the setting unit.

7. The printing device according to claim 6, characterized in that The second line is directly connected to the USB port and the print head, and delivers power relayed by the USB port directly to the print head.

8. The printing device according to claim 6 or 7, characterized in that: The printing device further comprises: a third switch for switching on and off power transmission of the third line; and The second control unit switches the third switch based on the voltage value set by the setting unit.

9. The printing device according to claim 6 or 7, characterized in that: The printing device further includes a fourth switch on the second line and the third line, the fourth switch switching between starting and stopping the relay of power in the USB port. The printing device further includes a third control unit that switches the fourth switch.

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