Printing apparatus

Abstract

To provide a printer which can suppress increase in the size without reducing print speed.SOLUTION: A printer can be driven by a plurality of power sources. A CPU determines a usable power source among the plurality of power sources on the basis of such a condition that the plurality of power sources are used (S9, S11 and S17). When it is determined that only one power source of a battery and an AC adapter is usable, the CPU supplies power of the one power source to a head and a conveyance motor (S27). When it is determined that both the battery and the AC adapter are usable, the CPU supplies at least a part of first power that is power of the battery connected to a battery mounting part to the head, and supplies at least a part of second power that is power of the AC adapter connected to an AC adapter jack to the conveyance motor (S27).SELECTED DRAWING: Figure 8

Description

Technical Field

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[0001] The present invention relates to a printing apparatus.

Background Art

[0002] <� The printing apparatus of Patent Document 1 is driven by power supply from a battery or an external power supply device. When both the battery and the external power supply device are connected, the printing apparatus is driven by the power supplied from the external power supply device. When both the battery and the external power supply device are connected and printing is executed, the printing apparatus is driven by the power supplied from the battery.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above printing apparatus, the output power may decrease depending on the environment in which the battery or the external power supply device is used, and the printing speed may decrease.

[0005] In addition, when a large amount of power is required to increase the printing speed, it is necessary to increase the size of the power source such as a battery. Therefore, the printing apparatus may become larger.

[0006] An object of the present invention is to provide a printing apparatus that can suppress a decrease in printing speed and an increase in size.

Means for Solving the Problems

[0007] The printing apparatus according to the present invention is a printing apparatus that can be driven by a plurality of power sources, comprising: a head that performs printing on a medium; a transport motor that generates power for transporting the medium; a first connection part to which a first power source can be connected; a second connection part to which a second power source can be connected; a determination means for determining which of the plurality of power sources is usable based on the conditions under which the plurality of power sources are used; and a power supply means for supplying power of the usable power source determined by the determination means to the head and the transport motor, wherein the power supply means, when determined by the determination means that only one of the first power source and the second power source is usable, supplies power of the one power source to the head and the transport motor; when determined by the determination means that both the first power source and the second power source are usable, supplies at least a portion of the first power, which is the power of the first power source connected to the first connection part, to the head and supplies at least a portion of the second power, which is the power of the second power source connected to the second connection part, to the transport motor.

[0008] In a printing device, the power supply status may result in insufficient power to drive the print head and motor. In this case, the printing device may, for example, divide a printing line into sections. Consequently, the printing speed may decrease due to insufficient power. The printing device will determine which power supplies are available in advance and then supply power from those available power supplies to the print head and motor. Therefore, the printing device can reduce the possibility of a decrease in printing speed. Furthermore, if the printing device determines that both the first and second power supplies are available, it will supply at least a portion of the first power from the first power supply to the print head and at least a portion of the second power supply to the transport motor. This allows the printing device to drive the print head and transport motor with power from different power supplies. Therefore, the printing device does not need to increase the size of each power supply to increase the power supply capacity in order to increase the printing speed. Thus, the printing device can maintain printing speed while suppressing the need for increased size.

[0009] In this invention, if the determination means determines that there is no usable power source among the multiple power sources, printing does not need to be performed. If a printing device attempts to print using a power source that does not meet the usable conditions, there may be insufficient power to drive the print head. This can result in a decrease in printing speed or a deterioration in print quality. If there is no usable power source, the printing device will not perform printing, thus avoiding printing in a state where the printing speed is reduced or the print quality may be deteriorated.

[0010] In the present invention, the determination means may determine that the first power supply is a usable power supply if the voltage output from the first power supply is equal to or greater than a first threshold, and may determine that the second power supply is a usable power supply if the voltage output from the second power supply is equal to or greater than a second threshold. The printing apparatus can determine whether the first power supply and the second power supply are usable power supplies using the voltages output by each.

[0011] In the present invention, the first power source is a battery, and the determination means may determine that the battery is a usable power source if the voltage output from the battery is equal to or greater than a first threshold. The printing apparatus can determine whether the battery is usable by comparing the voltage output from the battery with the first threshold.

[0012] In the present invention, the printing apparatus is provided with a third connection part to which a third power source can be connected. The determination means determines that the battery is unusable if the voltage output by the battery is less than the first threshold. The power supply means, when the determination means determines that the battery is an unusable power source and that the second power source and the third power source are usable power sources, may supply at least a portion of the second power from the second power source to the head and the transport motor, and at least a portion of the third power, which is power from the third power source, to the battery. The printing apparatus can drive the head and transport motor with the second power source while charging the battery with the third power source.

[0013] In the present invention, the determination means may determine that the third power supply is usable if it determines that the voltage output from the third power supply is equal to or greater than the third threshold. The printing apparatus can determine whether the third power supply is usable by comparing the voltage output from the third power supply with the third threshold.

[0014] In the present invention, the first threshold has a fourth threshold and a fifth threshold that is greater than the fourth threshold, and the determination means may determine that the battery is a usable power source if the power sources other than the battery among the plurality of power sources are unusable and the voltage output from the battery is equal to or greater than the fourth threshold, and may determine that the battery is a usable power source if the power sources other than the battery among the plurality of power sources are usable and the voltage output from the battery is equal to or greater than the fifth threshold. When multiple power sources are usable, the power that can be output from the battery increases. In this case, the printing device can determine whether there is sufficient first power that the battery can supply by setting the fifth threshold higher than the fourth threshold.

[0015] In the present invention, a detection unit is provided to detect the temperature of each of the multiple power supplies, and the determination means may determine that power supplies whose temperatures, as detected by the detection unit, fall within a predetermined temperature range are usable power supplies. The performance of a power supply changes with ambient temperature. The printing device determines in advance whether a power supply is usable based on the detected temperature of the power supply. Therefore, the printing device can avoid using power supplies that are likely to reduce the printing speed.

[0016] In the present invention, the determination means may determine that a power supply among the plurality of power supplies is usable if the power supply that can supply a current greater than the current required to drive the head and the current required to drive the transport motor is usable. The printing apparatus can determine whether a power supply is usable based on the supplyable current.

[0017] In the present invention, a third connection part to which a third power source can be connected is provided. The first power source is a battery, the third power source is a USB power supply part, and when the current that can be supplied by the USB power supply part is larger than the current required for driving the conveyance motor and the voltage output by the USB power supply part is equal to or higher than a sixth threshold value, the power of the power source of the USB power supply part is supplied to the conveyance motor, and the first power by the battery is supplied to the head. When the current that can be supplied by the USB power supply part is smaller than the current required for driving the conveyance motor and the voltage output by the USB power supply part is smaller than the sixth threshold value, the first power by the battery may be supplied to the head and the conveyance motor. The printing apparatus can control power supply based on the current and voltage that can be supplied by a battery, an AC adapter, and a USB power supply part.

Brief Description of the Drawings

[0018] [Figure 1] It is a perspective view of the printing apparatus 1. [Figure 2] It is a diagram showing the electrical configuration of the printing apparatus 1. [Figure 3] It is a block diagram showing the power source detection part 21A, the power management part 21B, and the power adjustment part 21C of the printing apparatus 1. [Figure 4] It is a table showing the drive patterns of the head 10 and the conveyance motor 9. [Figure 5] It is a circuit diagram showing the power supply circuit 100. [Figure 6] It is a diagram showing the first bleeder circuit 38A, the second bleeder circuit 38B, the first bleeder resistor 38C, and the second bleeder resistor 38D. [Figure 7] It is a diagram showing the lighting patterns of the LEDs 4A to 4D. [Figure 8] It is a flowchart showing the main process. [Figure 9] It is a flowchart showing the determination process. [Figure 10] It is a diagram showing the power supply circuit 100A in a modified example. [Figure 11]It is a diagram showing the power supply circuit 100B in the modified example.

Embodiments for Carrying Out the Invention

[0019] Referring to the drawings, the printing apparatus 1 according to an embodiment of the present invention will be described. Hereinafter, the lower left, upper right, upper left, lower right, upper, and lower parts of FIG. 1 are referred to as the front, rear, left, right, upper, and lower parts of the printing apparatus 1, respectively.

[0020] The printing apparatus 1 shown in FIGS. 1 and 2 can be driven by a plurality of power sources. The plurality of power sources include a battery 29, an AC adapter 30, and a USB power supply unit 31. In the printing apparatus 1, it is assumed that the AC adapter 30 and the USB power supply unit 31 are not used simultaneously. The printing apparatus 1 prints an image on a medium M based on print data. The medium M is not limited to a specific medium, but is, for example, sheet-like or tape-like, and is a thermal type cut paper in the present embodiment.

[0021] As shown in FIG. 1, the printing apparatus 1 includes a case 2. The case ② is rectangular parallelepiped and is longer in the left-right direction than in the front-back direction and the up-down direction. A battery mounting portion 34 (see FIG. 5) is provided at the lower rear portion of the case 2. The battery mounting portion 34 can connect the battery 29.

[0022] An AC adapter jack 32 and a USB jack 33 are provided at the right end portion of the case 2. The USB jack 33 is provided in front of the AC adapter jack 32. The AC adapter jack 32 can connect an AC adapter 30 (see FIG. 5) as an external power source. The USB jack 33 can connect a USB power supply unit 31 (see FIG. 5) as an external power source.

[0023] The operation unit 7 is provided at the left end portion of the case 2. The operation unit 7 is a physical button for inputting various instructions. The operation unit 7 only needs to be able to input various instructions, and may have a configuration such as a dial or a touch panel.

[0024] The display unit 4 is located at the leftmost and frontmost end of the printing device 1. The display unit 4 is capable of displaying various types of information. The display unit 4 consists of multiple LEDs 4A to 4D. The multiple LEDs 4A to 4D are arranged in a left-to-right direction.

[0025] The electrical configuration of the printing device 1 will be explained with reference to Figure 2. The printing device 1 comprises a power supply circuit 100 and a printing system 3. The power supply circuit 100 supplies power to the printing system 3 from a battery 29 (see Figures 3 and 5), an AC adapter 30 (see Figures 3 and 5), and a USB power supply unit 31 (see Figures 3 and 5). The power supplied by the battery 29 is called the first power. The power supplied by the AC adapter 30 is called the second power. The power supplied by the USB power supply unit 31 is called the third power. The first power is greater than the second power, and the second power is greater than the third power.

[0026] Battery 29 can output a voltage of 10.8V. AC adapter 30 can output a voltage of 15V. USB power supply unit 31 can output a voltage of 15V. USB power supply unit 31 is what is known as "USB Power Delivery".

[0027] The printing system 3 includes a CPU 21, ROM 22, RAM 24, drive circuits 11 and 12, transport motor 9, thermal head (hereinafter referred to as "head 10"), temperature sensor 25, operation unit 7, and display unit 4.

[0028] ROM 22, RAM 24, temperature sensor 25, operation unit 7, display unit 4, and drive circuits 11 and 12 are each electrically connected to the CPU 21. ROM 22 stores various programs necessary for controlling the printing device 1. The CPU 21 performs various calculations based on these programs. RAM 24 has a memory area where various calculation data are stored.

[0029] The temperature sensor 25 is located in the battery mounting section 34. The temperature sensor 25 detects the temperature of the battery 29. The temperature sensor 25 is connected to the CPU 21 and transmits the temperature detection result of the battery 29 to the CPU 21. The operation unit 7 is connected to the CPU 21 and transmits various instructions to the CPU 21. The display unit 4 is connected to the CPU 21 and displays various information.

[0030] A transport motor 9 is connected to the drive circuit 11. The transport motor 9 is located inside the case 2. The transport motor 9 generates power to transport the medium M. The transport motor 9 transports the medium M when driven by the drive circuit 11.

[0031] The head 10 is connected to the drive circuit 12. The head 10 is located inside the case 2. The head 10 performs printing on the medium M. The head 10 includes multiple heating elements. The head 10 selectively heats the multiple heating elements by being driven by the drive circuit 11. The CPU 21 performs printing on the medium M by driving the transport motor 9 and the head 10, respectively, via the drive circuits 11 and 12.

[0032] Referring to Figure 3, the power detection unit 21A, power management unit 21B, and power adjustment unit 21C of the CPU 21 will be explained. The power detection unit 21A detects whether an available power source is connected from among the AC adapter 30, USB power supply unit 31, and battery 29. The power detection unit 21A detects the voltage of the AC adapter 30, USB power supply unit 31, and battery 29, respectively. An ADC (Analog Digital Converter) is used for voltage detection.

[0033] The power detection unit 21A determines that the AC adapter 30 is a usable power source if the voltage output from the AC adapter 30 is equal to or greater than the second threshold. The second threshold is, for example, 13V. The first threshold will be described later. The power detection unit 21A also determines that the USB power supply unit 31 is a usable power source if the voltage output from the USB power supply unit 31 is equal to or greater than the third threshold. The third threshold is, for example, 11V.

[0034] The power detection unit 21A determines that the battery 29 is a usable power source if the voltage output from the battery 29 is equal to or greater than the first threshold. The CPU 21 determines that the battery 29 is unusable if the voltage output from the battery 29 is less than the first threshold.

[0035] The first threshold has a fourth threshold and a fifth threshold. The fifth threshold is greater than the fourth threshold. The fourth threshold is, for example, 8V. The fifth threshold is, for example, 9V. The power detection unit 21A determines that the battery 29 is a usable power source if, among the multiple power sources, power sources other than the battery 29 (AC adapter 30, USB power supply unit 31) are unusable, and the voltage output from the battery 29 is equal to or greater than the fourth threshold. In other words, the power detection unit 21A uses the fourth threshold when power sources other than the battery 29 (AC adapter 30 or USB power supply unit 31) are unusable.

[0036] The power detection unit 21A determines that the battery 29 is a usable power source if, among the multiple power sources, a power source other than the battery 29 (AC adapter 30 or USB power supply unit 31) is usable, and the voltage output from the battery 29 is equal to or greater than the fifth threshold. In other words, the power detection unit 21A uses the fifth threshold when a power source other than the battery 29 (AC adapter 30 or USB power supply unit 31) is usable.

[0037] The power management unit 21B manages the power required for printing by the print head 10 and the transport motor 9 based on the print data stored in the ROM 22 and RAM 24. The power required by the print head 10 is calculated based on data such as the number of on-dots per line. The power required by the transport motor 9 is calculated based on data such as the transport speed and transport amount during printing.

[0038] The power adjustment unit 21C determines the destination of each power supply according to the detection result of the power supply detection unit 21A and the calculation result of the power management unit 22B. The power adjustment unit 21C controls the power supply circuit 100, described later, to switch the destination of power supplied by each power supply. Note that the CPU 21, ROM 22, RAM 24, and temperature sensor 25 only need to be supplied with a portion of the power from any of the power supplies connected to the printing device 1.

[0039] The power adjustment unit 21C supplies power from the available power source to the head 10 and the transport motor 9. For example, if the CPU 21 determines that only one of the power sources among the battery 29, AC adapter 30, and USB power supply unit 31 is available, it supplies power from that one power source to the head 10 and the transport motor 9. For example, if only the battery 29 is available, at least a portion of the primary power from the battery 29 is supplied to the head 10 and the transport motor 9.

[0040] On the other hand, if the power adjustment unit 21C determines, for example, that both the battery 29 and the AC adapter 30 can be used, it supplies at least a portion of the first power, which is the power of the battery 29 connected to the battery mounting unit 34, to the head 10. In this case, the power adjustment unit 21C supplies at least a portion of the second power, which is the power of the AC adapter 30 connected to the AC adapter jack 32, to the transport motor 9.

[0041] Referring to Figure 4, the drive patterns of the printer 1 will be explained. If both the AC adapter 30 (USB power supply unit 31) and the battery 29 are determined to be unusable, the printer 1 will not be able to print. If the AC adapter 30 (USB power supply unit 31) is unusable and only the battery 29 is usable, the printer 1 will be powered solely by the battery 29.

[0042] If the AC adapter 30 (USB power supply unit 31) is available and only the battery 29 is unavailable, the printer will operate using only the AC adapter 30 (USB power supply unit 31). If both the AC adapter 30 (USB power supply unit 31) and the battery 29 are available, the printer 1 will operate using multiple power sources.

[0043] Referring to Figure 5, the power supply circuit 100 will be explained. The power supply circuit 100 supplies power to the head 10 and the transport motor 9 based on power from either the battery 29, the AC adapter 30, or the USB power supply unit 31. In other words, the power supply circuit 100 supplies the head 10 and the transport motor 9 with the first power from the battery 29, the second power from the AC adapter 30, and the third power from the USB power supply unit 31.

[0044] The power supply circuit 100 includes an AC adapter jack 32, a USB jack 33, a battery mounting section 34, a voltage conversion section 39, wiring L1 to L5, switching sections SW1 to SW3, and a bleeder circuit 38.

[0045] The AC adapter jack 32 is electrically connected to the anode of diode D1. The cathode of diode D1 is electrically connected to the first switching unit SW1. The first switching unit SW1 is an on / off switchable electronic device such as a transistor. The first switching unit SW1 is electrically connected to the drive circuit 12. The drive circuit 12 is electrically connected to the head 10. Hereinafter, the wiring that electrically connects the AC adapter jack 32 and the head 10 will be referred to as the "first wiring L1". The first switching unit SW1 switches the first wiring L1 between a conductive state and a non-conductive state.

[0046] The second switching unit SW2 is electrically connected between the cathode of diode D1 in the first wiring L1 and the first switching unit SW1. The second switching unit SW2 is connected to the anode of diode D2. The second switching unit SW2 is an on / off switchable electronic device such as a transistor. The cathode of diode D2 is electrically connected to the drive circuit 11. The drive circuit 11 is electrically connected to the transport motor 9. Hereinafter, the wiring that electrically connects the AC adapter jack 32 and the transport motor 9 will be referred to as the "second wiring L2". The second switching unit SW2 switches the second wiring L2 between a conductive state and a non-conductive state.

[0047] The third switching unit SW3 is electrically connected between the first switching unit SW1 and the drive circuit 12 in the first wiring L1. The third switching unit SW3 is an on / off switchable electronic device such as a transistor. The third switching unit SW3 is connected to the anode of diode D3. The cathode of diode D3 is electrically connected between the second switching unit SW2 and the drive circuit 11 in the second wiring L2. Hereinafter, the wiring that electrically connects the first switching unit SW1 and the drive circuit 12 in the first wiring L1 and the second switching unit SW2 and the drive circuit 11 in the second wiring L2 will be referred to as the "third wiring L3". The third switching unit SW3 switches the third wiring L3 between a conductive state and a non-conductive state.

[0048] The battery mounting section 34 is connected to the voltage conversion section 39. The voltage conversion section 39 boosts the voltage of the battery 29 to 15V. The voltage conversion section 39 is connected to the anode of diode D4. The cathode of diode D4 is electrically connected between the first switching section SW1 and the drive circuit 12 of the first wiring L1. Hereinafter, the wiring connected to the battery 29 and electrically connected between the first switching section SW1 and the drive circuit 12 of the first wiring L1 will be referred to as the "fourth wiring L4".

[0049] The USB jack 33 can be connected to the USB power supply unit 31. The USB jack 33 is connected to the anode of diode D5. The cathode of diode D5 is electrically connected between the first switching unit SW1 and the cathode of diode D1 in the first wiring L1. Hereinafter, the wiring connected to the USB jack 33 and electrically connected between the AC adapter jack 32 and the first switching unit SW1 in the first wiring L1 will be referred to as the "fifth wiring L5".

[0050] The following describes operation using only the battery 29 as a single power source. In this case, the AC adapter 30 and USB power supply unit 31 are not connected to the AC adapter jack 32 and USB jack 33. The power adjustment unit 21C turns on the third switch SW3 and turns off the first switch SW1 and the second switch SW2. As a result, at least a portion of the primary power from the battery 29 is supplied to the head 10 via the fourth wiring L4 and the first wiring L1. In addition, at least a portion of the primary power from the battery 29 is supplied to the transport motor 9 via the fourth wiring L4, the first wiring L1, the third wiring L3, and the second wiring L2. In other words, when the battery 29 is connected to the battery mounting unit 34 and the AC adapter 30 is not connected to the AC adapter jack 32, the power supply circuit 100 supplies at least a portion of the primary power to the head 10 and the transport motor 9.

[0051] The following describes operation using only the AC adapter 30 as a single power source. In this case, the battery 29 and USB power supply unit 31 are not connected to the battery mounting unit 34 and USB jack 33. The power adjustment unit 21C turns on the first switch SW1 and the second switch SW2, and turns off the third switch SW3. As a result, at least a portion of the secondary power from the AC adapter 30 is supplied to the head 10 via the first wiring L1. Also, at least a portion of the secondary power from the AC adapter 30 is supplied to the transport motor 9 via the second wiring L2. In other words, the power supply circuit 100 supplies at least a portion of the secondary power to the head 10 and the transport motor 9 when the AC adapter 30 is connected to the AC adapter jack 32 and the battery 29 is not connected to the battery mounting unit 34.

[0052] The following describes operation using only the USB power supply unit 31 as a single power source. In this case, the battery 29 and AC adapter 30 are not connected to the battery mounting unit 34 and the USB jack 33. The power adjustment unit 21C turns on the first switch SW1 and the second switch SW2, and turns off the third switch SW3. As a result, at least a portion of the third power from the USB power supply unit 31 is supplied to the head 10 via the fifth wiring L5 and the first wiring L1. In addition, at least a portion of the third power from the USB power supply unit 31 is supplied to the transport motor 9 via the fifth wiring L5 and the second wiring L2.

[0053] The operation using multiple power sources, battery 29 and AC adapter 30, will now be described. In this case, the connection of the USB power supply unit 31 is irrelevant. For example, if both the AC adapter 30 and the USB power supply unit 31 are connected to the printer 1 at the same time, the AC adapter 30 should be used preferentially. The power adjustment unit 21C turns on the second switching unit SW2 and turns off the first switching unit SW1 and the third switching unit SW3. As a result, at least a portion of the first power from battery 29 is supplied only to the head 10 via the fourth wiring L4 and the first wiring L1. Also, at least a portion of the second power from AC adapter 30 is supplied only to the transport motor 9 via the second wiring L2. In other words, when battery 29 is connected to battery mounting unit 34 and AC adapter 30 is connected to AC adapter jack 32, the power supply circuit 100 supplies at least a portion of the first power to the head 10 and at least a portion of the second power to the transport motor 9.

[0054] The following describes operation using multiple power sources, the battery 29 and the USB power supply unit 31. In this case, the AC adapter 30 is not connected to the AC adapter jack 32. The power adjustment unit 21C turns on the second switch SW2 and turns off the first switch SW1 and the third switch SW3. As a result, at least a portion of the first power from the battery 29 is supplied only to the head 10 via the fourth wiring L4 and the first wiring L1. Also, at least a portion of the third power from the USB power supply unit 31 is supplied only to the transport motor 9 via the fifth wiring L5 and the second wiring L2. In other words, when the battery 29 is connected to the battery mounting unit 34 and the USB power supply unit 31 is connected to the USB jack 33, the power supply circuit 100 supplies at least a portion of the first power to the head 10 and at least a portion of the third power to the transport motor 9.

[0055] As described above, when the system is driven by multiple power sources, the power supply circuit 100 simultaneously supplies at least a portion of the first power to the head 10 and at least a portion of the second or third power to the transport motor 9.

[0056] The bleeder circuit 38 will be described with reference to Figure 6. The bleeder circuit 38 comprises a first bleeder circuit 38A, a first bleeder resistor 38C, a second bleeder circuit 38B, and a second bleeder resistor 38D.

[0057] The first bleeder circuit 38A discharges the charge generated in the USB jack 33 when the USB power supply unit 31 is not connected. The first bleeder circuit 38A comprises resistors R1 to R3 and transistors Tr1 and Tr2. One end of resistor R1 is electrically connected to the fifth wiring L5. The other end of resistor R1 is electrically connected to one end of resistor R2. The other end of resistor R2 is electrically connected to ground GND. One end of resistor R3 is electrically connected to the first wiring L1.

[0058] The base of transistor Tr1 is electrically connected to one end of resistor R2. The collector of transistor Tr1 is electrically connected to the other end of resistor R3. The emitter of transistor Tr1 is electrically connected to ground (GND).

[0059] The base of transistor Tr2 is electrically connected to the other end of resistor R3 and to the collector of transistor Tr1. The emitter of transistor Tr2 is electrically connected to ground GND. The collector of transistor Tr2 is connected to one end of the first bleeder resistor 38C. The other end of the first bleeder resistor 38C is connected to the fifth wire L5. In other words, the first bleeder circuit 38A is connected to the first wire L1, the fifth wire L5, and ground GND. Also, the first bleeder resistor 38C is connected to the first bleeder circuit 38A and also to the fifth wire L5.

[0060] The second bleeder circuit 38B discharges the charge generated at the AC adapter jack 32 when the AC adapter 30 is not connected. The second bleeder circuit 38B comprises resistors R11 to R13 and transistors Tr11 and Tr12. One end of resistor R11 is electrically connected to the first wiring L1. The other end of resistor R11 is electrically connected to one end of resistor R12. The other end of resistor R12 is electrically connected to ground GND. One end of resistor R13 is electrically connected to the fifth wiring L5.

[0061] The base of transistor Tr11 is electrically connected to one end of resistor R12. The collector of transistor Tr1 is electrically connected to the other end of resistor R13. The emitter of transistor Tr11 is electrically connected to ground (GND).

[0062] The base of transistor Tr12 is electrically connected to the other end of resistor R13 and to the collector of transistor Tr11. The emitter of transistor Tr12 is electrically connected to ground (GND). The collector of transistor Tr12 is connected to one end of the second bleeder resistor 38D. The other end of the second bleeder resistor 38D is connected to the first wiring L1. In other words, the second bleeder circuit 38B is connected to the first wiring L1, the fifth wiring L5, and ground (GND). Also, the second bleeder resistor 38D is connected to the second bleeder circuit 38B and also to the first wiring L1.

[0063] The following describes the case where the AC adapter 30 is connected to the AC adapter jack 32, and the USB power supply unit 31 is not connected to the USB jack 33. In this case, transistor Tr1 is in the off state because it does not receive power from the USB jack 33. On the other hand, transistor Tr2 is in the on state because it receives power from the AC adapter jack 32.

[0064] Here, if charge is accumulated in the fifth wire L5, the first bleeder circuit 38A discharges the charge to ground GND via resistors R1 and R2. In this case, some charge that cannot be discharged by the first bleeder circuit 38A may remain in the fifth wire L5. The charge remaining in the fifth wire L5 is discharged to ground GND via the first bleeder resistor 38C and transistor Tr2. As a result, the first bleeder circuit 38A and the first bleeder resistor 38C can suppress the generation of voltage in the USB jack 33 and the fifth wire L5, to which the USB power supply unit 31 is not connected.

[0065] The following describes the case where the USB power supply unit 31 is connected to the USB jack 33, and the AC adapter 30 is not connected to the AC adapter jack 32. In this case, transistor Tr11 is in the off state because it does not receive power from the AC adapter 30. On the other hand, transistor Tr12 is in the on state because it receives power from the USB power supply unit 31.

[0066] Here, if charge is accumulated in the first wiring L1, the second bleeder circuit 38B discharges the charge to ground GND via resistors R11 and R12. In this case, some charge may remain in the first wiring L1 that the second bleeder circuit 38B cannot discharge. The charge remaining in the first wiring L1 is discharged to ground GND via the second bleeder resistor 38D and transistor Tr12. As a result, the second bleeder circuit 38B and the second bleeder resistor 38D can suppress the generation of voltage on the AC adapter jack 32 and the first wiring L1 when the AC adapter 30 is not connected.

[0067] Referring to Figure 7, the display unit 4 will be described. The display unit 4 displays information on which power source is being used: the AC adapter 30, the USB power supply unit 31, or the battery 29. The display mode of the display unit 4 includes a first mode (see Figures 7(A) to 7(C)) and a second mode (see Figures 7(D) and 7(E)). Each mode can be pre-set by the user.

[0068] As shown in Figures 7(A) to 7(C), in the first mode, LEDs 4A to 4C are used. For example, battery 29 corresponds to LED 4A. When battery 29 is in use, LED 4A lights up. AC adapter 30 corresponds to LED 4B. When AC adapter 30 is in use, LED 4B lights up. USB power supply unit 31 corresponds to LED 4C. When USB power supply unit 31 is in use, LED 4C lights up.

[0069] For example, if the printer 1 is powered by a single power source, the battery 29, only LED 4A will light up (see Figure 7(A)). For example, if the printer 1 is powered by multiple power sources, the battery 29 and the AC adapter 30, LED 4A and LED 4B will light up (see Figure 7(B)). For example, if the printer 1 is powered by multiple power sources, the battery 29 and the USB power supply unit 31, LED 4A and LED 4C will light up (see Figure 7(C)). In other words, the display unit 4 consists of multiple LEDs 4A to 4C, which are provided to correspond to multiple power sources, and the multiple LEDs 4A to 4C light up according to the power source being used.

[0070] As shown in Figures 7(D) and 7(E), in the second mode, only LED4D is used. For example, LED4D can emit multiple colors depending on the power supply being used. LED4D lights up in the color corresponding to the power supply being used. For example, when powered by a single power source, battery 29 only, LED4D lights up red. When powered by multiple power sources, battery 29 and AC adapter 30, LED4D lights up blue.

[0071] Referring to Figure 8, the main process will be explained. First, the user connects power to the printer 1. In this state, when the user operates the control unit 7 and powers up the printer 1, the CPU 21 reads the program from the ROM 22 and executes the main process. Once the main process is executed, the CPU 21 specifies one of several power sources (S1). In this case, the CPU 21 specifies either the AC adapter 30, the USB power supply unit 31, or the battery 29.

[0072] The CPU 21 obtains the voltage of the specified power supply using the power supply detection unit 21A (S3). Next, the CPU 21 determines whether the power supply from which the voltage was obtained was the battery 29 or not (S5). If it is determined that it was not the battery 29 (S5: NO), the CPU 21 determines whether the voltage obtained in the S3 process is above a predetermined threshold (S7). In this case, the CPU 21 uses either the second threshold or the third threshold as the predetermined threshold. If the specified power supply is the AC adapter 30, the CPU 21 compares the voltage obtained in the S3 process with the second threshold. If the specified power supply is the USB power supply unit 31, the CPU 21 compares the voltage obtained in the S3 process with the third threshold.

[0073] If the CPU 21 determines that the voltage obtained in process S3 is above a predetermined threshold (S7: YES), it determines that the power supply specified in process S1 is available (S9). In this case, the CPU 21 temporarily stores the information that the power supply specified in process S1 is available in RAM 24. The CPU 21 then proceeds to process S19.

[0074] On the other hand, if the CPU 21 determines that the voltage detected in processing S3 is less than a predetermined threshold (S7: NO), it determines that the power supply specified in processing S1 is unavailable (S11). In this case, the CPU 21 temporarily stores the information that the power supply specified in processing S1 is unavailable in RAM 24. The CPU 21 then proceeds to processing S19.

[0075] On the other hand, if the CPU 21 determines that the power source from which the voltage was obtained is the battery 29 (S5: YES), the CPU 21 obtains the temperature of the battery 29 (S13). In this case, the CPU 21 temporarily stores the detection result from the temperature sensor 25 in the RAM 24.

[0076] The CPU 21 determines whether the temperature of the battery 29, obtained from the temperature sensor 25, is within a predetermined temperature range (S15). Here, the predetermined temperature range is a value based on the specifications of the battery 29, and is the range in which the battery 29 can normally output primary power. For example, the predetermined temperature range is -15°C to 60°C.

[0077] If the temperature of the battery 29, as determined by the temperature sensor 25, is outside a predetermined temperature range (S15: NO), the CPU 21 determines that the battery 29 is unusable (S11). In this case, the CPU 21 temporarily stores the information that the battery 29 is unusable in the RAM 24. The CPU 21 then proceeds to process S19.

[0078] If the temperature of the battery 29 obtained from the temperature sensor 25 is determined to be within a predetermined temperature range (S15: YES), the CPU 21 determines that the battery 29 is usable (S17). In this case, the CPU 21 temporarily stores the information that the battery 29 is usable in the RAM 24. The CPU 21 then proceeds to process S19.

[0079] CPU21 determines whether the availability check for all power supplies has been completed (S19). If it determines that the availability check for all power supplies has not been completed (S19: NO), CPU21 returns to S1 and specifies the next power supply. If it determines that the availability check for all power supplies has been completed (S19: YES), CPU21 executes the determination process (S21).

[0080] The determination process will be explained with reference to Figure 9. When the determination process starts, the CPU 21 determines whether a power source other than the battery 29 is available (S101). In this case, the CPU 21 determines whether the AC adapter 30 and the USB power supply unit 31 can be used based on the information stored in the RAM 24.

[0081] If it is determined that no power source other than battery 29 is available (S101: NO), the CPU 21 determines whether battery 29 is available or not (S103). In this case, the CPU 21 refers to RAM 24 to determine whether battery 29 is available or not.

[0082] If the CPU determines that battery 29 is unusable (S103: NO), it determines that there are no usable power sources and therefore all power sources are unusable (S105). In this case, the CPU 21 stores the information that all power sources are unusable in RAM 24. The CPU 21 returns to the main process and executes the process in S23. In this case, the CPU 21 does not execute printing after the main process is completed because there are no usable power sources among the multiple power sources.

[0083] On the other hand, if it is determined that the battery 29 is usable (S103: YES), the CPU 21 determines whether the voltage of the battery 29 is above a predetermined threshold (S107). In this case, the CPU 21 uses the fourth threshold as the predetermined threshold. If it is determined that the voltage of the battery 29 is above the predetermined threshold (S107: YES), the CPU 21 determines that only the battery 29 is usable (S109). In this case, the printing device 1 can be powered solely by the battery 29. The CPU 21 temporarily stores the information that only the battery 29 is usable in the RAM 24. The CPU 21 returns to the main process and executes the process in S23.

[0084] On the other hand, if it is determined that a power source other than the battery 29 is available (S101: YES), the CPU 21 determines whether the battery 29 is available or not (S111). If it is determined that the battery 29 is unavailable (S111: NO), the CPU 21 determines that only power sources other than the battery 29 are available (S113). In this case, the printer 1 can be driven by a single power source, either the AC adapter 30 or the USB power supply unit 31. The CPU 21 temporarily stores the information that only the AC adapter 30 or the USB power supply unit 31 is available in the RAM 24. The CPU 21 then returns to the main process and executes the process in S23.

[0085] If the CPU determines that the battery 29 is usable (S111: YES), it determines whether the voltage of the battery 29 is above a predetermined threshold (S115). In this case, the CPU 21 uses the fifth threshold as the predetermined threshold. If the CPU determines that the voltage of the battery 29 is below the predetermined threshold (S115: NO), it determines that only power sources other than the battery 29 are usable (S113). In this case, the printer 1 can be powered by a single power source, either the AC adapter 30 or the USB power supply unit 31. The CPU 21 temporarily stores the information that only the AC adapter 30 or the USB power supply unit 31 is usable in the RAM 24. The CPU 21 returns to the main process and executes the process in S23.

[0086] On the other hand, if the CPU 21 determines that the voltage of the battery 29 is above a predetermined threshold (S115: YES), it determines that the battery 29 and other power sources are usable (S117). In this case, it becomes possible to power the device with multiple power sources, either the AC adapter 30 or the USB power supply unit 31 and the battery 29. The CPU 21 temporarily stores in the RAM 24 the information that the AC adapter 30 or the USB power supply unit 31 and the battery 29 are usable. The CPU 21 then returns to the main process and executes the process in S23.

[0087] When the S21 judgment process is completed, the CPU 21 determines whether all power supplies were unusable (S23). If all power supplies were unusable (S23: YES), the CPU 21 notifies the user that all power supplies are unusable (S25). For example, the CPU 21 flashes LEDs 4A to 4D in red. This allows the user to recognize that all power supplies are unusable. The CPU 21 then terminates processing.

[0088] On the other hand, if it is determined that not all power sources are unusable (S23: NO), the CPU 21 performs power supply processing based on the available power sources stored in the RAM 24 (S27). When powered by a single power source, the battery 29, the CPU 21 supplies at least a portion of the first power from the battery 29 to the head 10 and the transport motor 9. When powered by a single power source, the AC adapter 30, the CPU 21 supplies at least a portion of the second power from the AC adapter 30 to the head 10 and the transport motor 9. When powered by a single power source, the USB power supply unit 31, the CPU 21 supplies at least a portion of the third power from the USB power supply unit 31 to the head 10 and the transport motor 9.

[0089] When powered by multiple power sources, including the battery 29 and the AC adapter 30, the CPU 21 supplies at least a portion of the primary power from the battery 29 to the head 10 and at least a portion of the secondary power from the AC adapter 30 to the transport motor 9.

[0090] When the printer is powered by multiple power sources, the battery 29 and the USB power supply unit 31, the CPU 21 supplies at least a portion of the first power from the battery 29 to the head 10 and at least a portion of the third power from the USB power supply unit 31 to the transport motor 9. The CPU 21 then terminates processing. After that, the printer 1 becomes ready to print.

[0091] As explained above, if the CPU 21 determines that only one of the power sources, the battery 29 or the AC adapter 30, is available, it supplies power from the one power source to the head 10 and the transport motor 9. If the CPU 21 determines that both the battery 29 and the AC adapter 30 are available, it supplies at least a portion of the first power, which is the power from the battery 29 connected to the first connection, to the head 10. The CPU 21 supplies at least a portion of the second power, which is the power from the AC adapter 30 connected to the AC adapter jack 32, to the transport motor 9.

[0092] In the printing device 1, depending on the power supply status, there may be insufficient power to drive the head 10 and motor. In this case, the printing device 1 will, for example, divide the printing of one line into sections. Therefore, the printing speed of the printing device 1 may decrease due to insufficient power. The printing device 1 will determine which power supply is available in advance and then supply power from the available power supply to the head 10 and motor. Therefore, the printing device 1 can reduce the possibility of a decrease in printing speed. Furthermore, if the printing device 1 determines that both the battery 29 and the AC adapter 30 are usable, it will supply at least a portion of the first power from the battery 29 to the head 10 and at least a portion of the second power to the transport motor 9. In this way, the printing device 1 can drive the head 10 and the transport motor 9 with power from different power supplies. Therefore, the printing device 1 does not need to increase the size of each power supply to increase the power supply capacity in order to increase the printing speed. Thus, the printing device 1 can maintain a high printing speed while suppressing the need for increased size.

[0093] If CPU 21 determines that there are no usable power sources among the multiple power sources, it will not perform printing. If printer 1 attempts to print using a power source that does not meet the usable conditions, it may not have enough power to drive the head 10. This could result in a decrease in printing speed or a deterioration in print quality. If there are no usable power sources, printer 1 will not perform printing, thus avoiding printing in a state where the printing speed is reduced or the print quality may be deteriorated.

[0094] The CPU 21 determines that the battery 29 is a usable power source if the voltage output from the battery 29 is above the first threshold. The CPU 21 determines that the AC adapter 30 is a usable power source if the voltage output from the AC adapter 30 is above the second threshold. The printing device 1 can determine whether the battery 29 and the AC adapter 30 are usable power sources using the voltages output by each.

[0095] The CPU 21 determines that the USB power supply unit 31 is usable if it determines that the voltage output from the USB power supply unit 31 is equal to or greater than the third threshold. The printing device 1 can determine whether the USB power supply unit 31 is usable by comparing the voltage output from the USB power supply unit 31 with the third threshold.

[0096] The first threshold has a fourth threshold and a fifth threshold that is greater than the fourth threshold. The CPU 21 determines that battery 29 is a usable power source if all power sources other than battery 29 are unusable and the voltage output from battery 29 is equal to or greater than the fourth threshold. The CPU 21 also determines that battery 29 is a usable power source if all power sources other than battery 29 are usable and the voltage output from battery 29 is equal to or greater than the fifth threshold. When multiple power sources are usable, the power that can be output from battery 29 increases. In this case, the printing device 1 can determine whether there is sufficient first power that battery 29 can supply by setting the fifth threshold higher than the fourth threshold.

[0097] The temperature sensor 25 detects the temperature of the battery 29. The CPU 21 determines that a power source whose temperature, as detected by the temperature sensor 25, falls within a predetermined temperature range is a usable power source. The performance of the battery 29 varies with ambient temperature. The printing device 1 makes a prior determination of whether a power source is usable based on the detected temperature of the battery 29. Therefore, the printing device 1 can avoid using a power source that is likely to reduce the printing speed.

[0098] In the above embodiment, the battery mounting section 34 corresponds to the "first connection section" of the present invention. The battery 29 corresponds to the "first power supply" of the present invention. The AC adapter jack 32 corresponds to the "second connection section" of the present invention. The AC adapter 30 corresponds to the "second power supply" of the present invention. The USB jack 33 corresponds to the "third power supply" of the present invention. The temperature sensor 25 corresponds to the "detection section" of the present invention. The CPU 21 that executes the processes S9, S11, S17, S105, S109, S113, and S117 corresponds to the "decision means" of the present invention. The CPU 21 that executes the process S27 corresponds to the "power supply means" of the present invention.

[0099] Referring to Figure 10, a modified power supply circuit 100A will be described. Power supply circuit 100A differs from power supply circuit 100 of the above embodiment in that it does not include a USB jack 33, diode D5, and fifth wiring L5. Even in this case, the printing device 1 can be driven by a single power source, either the battery 29 or the AC adapter 30. Furthermore, the printing device 1 can be driven by multiple power sources, such as the battery 29 and the AC adapter 30.

[0100] Referring to Figure 11, a modified power supply circuit 100B will be described. Power supply circuit 100B differs from power supply circuit 100A in that it includes a fourth switching unit SW4 and a sixth wiring L6. Also, when power supply circuit 100B is used, the head 10 has two supply units for supplying power. The parts of the head 10 supplied by the two supply units are called the first part and the second part, respectively.

[0101] The fourth switching unit SW4 is electrically connected between the AC adapter jack 32 and the first switching unit SW1 of the first wiring L1. The fourth switching unit SW4 is electrically connected to the drive circuit 12. The sixth wiring 6 is the wiring that connects the AC adapter jack 32 and the head 10.

[0102] The following describes the case where the first switching unit SW1, the second switching unit SW2, and the fourth switching unit SW4 are turned on by the power adjustment unit 21C, and the third switching unit SW3 is turned off. In this case, the printing device 1 is driven by a single power supply, the AC adapter 30. In this case, at least a portion of the second power supplied from the AC adapter 30 is supplied to the drive circuit 12 via the first wiring L1 and the sixth wiring L6. The drive circuit 12 supplies the second power supplied via the first wiring L1 to the first part of the head 10. The drive circuit 12 can also supply the second power via the sixth wiring L6 to the second part of the head 10. In this case, at least a portion of the second power supplied from the AC adapter 30 is supplied to the transport motor 9 via the second wiring L2. Alternatively, at least a portion of the second power supplied from the AC adapter 30 may be supplied to the transport motor 9 via the first wiring L1, the third wiring L3, and the second wiring L2.

[0103] The following describes the case where the fourth switching unit SW4 and the third switching unit SW3 are turned on by the power adjustment unit 21C, and the first switching unit SW1 and the second switching unit SW2 are turned off. In this case, the printing device 1 is powered by multiple power sources, the battery 29 and the AC adapter 30. That is, the battery 29 is connected to the battery mounting unit 34, and the AC adapter 30 is connected to the AC adapter jack 32. In this case, the power supply circuit 100B supplies at least a portion of the first power to the first part of the head 10 via the fourth wiring L4 and the first wiring L1. The power supply circuit 100B supplies at least a portion of the first power to the transport motor 9 via the fourth wiring L4 and the third wiring L3. The power supply circuit 100B supplies at least a portion of the second power to a second part of the head 10 that is different from the first part, via the sixth wiring L6. This allows the printing device 1 to efficiently use multiple power sources without increasing its size. Note that the power supply circuit 100B may be connected to a USB power supply unit 31 instead of the AC adapter 30.

[0104] The present invention can be further modified from the above embodiments. The printing device 1 described above performs printing on thermal-type cut paper, but is not limited thereto. For example, the printing device 1 may be a thermal transfer printer or an inkjet printer.

[0105] The printer was powered by three power sources: a battery 29, an AC adapter 30, and a USB power supply unit 31, but is not limited to these. For example, the printer 1 may be able to connect to two or fewer power sources. Also, the printer 1 may be able to connect to four or more power sources.

[0106] In the above embodiment, it is assumed that either the AC adapter 30 or the USB power supply unit 31 is connected, but it is not limited to this. For example, both the AC adapter 30 and the USB power supply unit 31 may be connected simultaneously. In other words, the battery 29, AC adapter 30, and USB power supply unit 31 may be connected to the printing device 1 at the same time.

[0107] For example, in the power supply circuit 100, a battery 29 is connected to the battery mounting section 34, an AC adapter 30 is connected to the AC adapter jack 32, and a USB power supply unit 31 is connected to the USB jack 33. In this case, the CPU 21 may supply at least a portion of the first power to the head 10 and at least a portion of the second power to the transport motor 9. When the battery 29, AC adapter 30, and USB power supply unit 31 are connected, the printing device 1 will preferentially use the battery 29 and AC adapter 30. The printing device 1 does not spend time selecting a power source. Therefore, the printing device 1 can be made faster.

[0108] In the above embodiment, the power supply circuit 100 supplies at least a portion of the first power from the battery 29 to the head 10 and at least a portion of the second power from the AC adapter 30 to the transport motor 9, but is not limited to this. For example, the power supply circuit 100 may determine the destination of each power supply based on the power consumed by the head 10 and the transport motor 9.

[0109] In other words, the power supply circuit 100 may supply at least a portion of the first power and at least a portion of the second power of the battery 29 to one of the head 10 and the transport motor 9, based on the power consumed by the head 10 and the transport motor 9. In this case, the power supply circuit 100 may also supply at least a portion of the first power and at least a portion of the second power to the other of the head 10 and the transport motor 9, based on the power consumed by the head 10 and the transport motor 9.

[0110] In this case, the printing device 1 can efficiently supply the first power from the battery 29 and the second power from the AC adapter 30 to the head 10 and the transport motor 9, respectively, based on the power consumed by the head 10 and the transport motor 9. Therefore, the printing device 1 does not need to increase the size of each power source to drive the head 10 and the transport motor 9. Thus, the printing device 1 can avoid becoming larger.

[0111] Furthermore, the power supply circuit 100 should supply power from the power source with the greater power supply capacity of the battery 29 and the AC adapter 30 to the one that consumes more power among the head 10 and the transport motor 9. Alternatively, the power supply circuit 100 should supply power from the power source with the smaller power supply capacity of the battery 29 and the AC adapter 30 to the one that consumes less power among the head 10 and the transport motor 9. The printing device 1 can supply power from a power source that can supply a large amount of power to the one that consumes more power. Also, the printing device 1 can supply power from a power source that can supply a small amount of power to the one that consumes less power.

[0112] More specifically, the power supply circuit 100 may, when the power consumed by the transport motor 9 is lower than the power consumed by the head 10, supply at least a portion of the first power from the battery 29 to the transport motor 9 and at least a portion of the second power from the AC adapter 30 to the head 10.

[0113] In the above embodiment, the first power was greater than the second power, but this is not limited to this. For example, the first power may be lower than the second power. In this case, the power supply circuit 100 may determine the destination of the power supply according to the power required by the head 10 and the transport motor 9. The relative magnitudes of the first power, second power, and third power may be changed as appropriate.

[0114] The voltages output by the battery 29, AC adapter 30, and USB power supply unit 31 in the above embodiment may be changed as appropriate. The first to fifth threshold values ​​may be changed as appropriate. For example, the first to fifth threshold values ​​may all be different values, or they may all be the same value.

[0115] In the above embodiment, the battery 29 is deemed usable when the voltage output from the battery 29 is equal to or greater than the first threshold, but this is not limited to this. Other values ​​may be used as thresholds instead of the first threshold.

[0116] In the above embodiment, the temperature of the battery 29 is detected by the temperature sensor 25, but the invention is not limited to this. The printing device 1 may also be equipped with sensors to detect the temperatures of the AC adapter 30 and the USB power supply unit 31, respectively. In this case, the CPU 21 only needs to determine that power supplies whose temperatures, as detected by the sensors, fall within a predetermined temperature range are usable power supplies.

[0117] In the above embodiment, the usable power supply was determined based on the voltage that multiple power supplies can supply, but it is not limited to this. For example, the CPU 21 may determine the usable power supply based on the current that multiple power supplies can supply. In this case, the CPU 21 obtains the current required to drive the head 10 and the transport motor 9. The CPU 21 determines whether a power supply is usable based on whether multiple power supplies can supply the current required to drive the head 10 and the transport motor 9. The CPU 21 determines that the power supply that can supply a current greater than the current required to drive the head 10 and the current required to drive the transport motor 9 is a usable power supply. The printing device 1 can determine whether a power supply is usable based on the supplyable current.

[0118] The CPU 21 may supply power from the USB power supply unit 31 to the transport motor 9 and the first power from the battery 29 to the head 10 if the current that can be supplied by the USB power supply unit 31 is greater than the current required to drive the transport motor 9, and the voltage output by the USB power supply unit 31 is equal to or greater than the sixth threshold. Alternatively, the CPU 21 may supply the first power from the battery 29 to the head 10 and the transport motor 9 if the current that can be supplied by the USB power supply unit 31 is less than the current required to drive the transport motor 9, and the voltage output by the USB power supply unit 31 is less than the sixth threshold. The printing device 1 can control the power supply based on the current and voltage that can be supplied by the battery 29, AC adapter 30, and USB power supply unit 31. The value of the sixth threshold can be set as appropriate.

[0119] In the above embodiment, either the AC adapter 30 or the USB power supply unit 31 was used, but they may be used simultaneously. In this case, the battery 29 may be charged using the second or third power supply. For example, if the CPU 21 determines that the battery 29 is an unusable power source and that the AC adapter 30 and the USB power supply unit 31 are usable power sources, it may supply at least a portion of the second power from the AC adapter 30 to the head 10 and the transport motor 9. In this case, the CPU 21 may supply at least a portion of the third power, which is power from the USB power supply unit 31, to the battery 29. This allows the printing device 1 to perform printing while charging the battery 29.

[0120] In the above embodiment, four LEDs 4A to 4D are provided as the display unit 4, but the number is not limited to this. For example, the number of LEDs may be three or less, or five or more. In the first pattern, LEDs 4A to 4C were used, but the system is not limited to these. In the first pattern, for example, LEDs 4B to 4D may be used. In the second pattern, LED 4D was used, but the system is not limited to this. For example, any of LEDs 4A to 4C may be used.

[0121] The display unit 4 indicates the power supply being used to the user by the lighting patterns of LEDs 4A to 4C, but is not limited to this. For example, the available power supply may be identified by a combination of the lighting patterns of two LEDs, 4A and 4C. Also, the available power supply is indicated to the user by the color of LED 4C, but is not limited to this. For example, the available power supply may be identified according to the blinking speed of LED 4A.

[0122] The display unit 4 consisted of LEDs 4A to 4C, but is not limited to these. For example, a display may be provided to show the available power supply in text or other format. Alternatively, the display unit 4 may notify the user of the available power supply via voice.

[0123] Instead of the CPU 21, a microcomputer, ASIC, FPGA (Field Programmable Gate Array), etc., may be used as the processor. The main processing may be distributed among multiple processors. The printing system 3 may also include other non-temporary storage media, such as flash memory or HDD. The non-temporary storage media can be any storage medium capable of retaining information regardless of the period for which the information is stored. The non-temporary storage media does not have to include temporary storage media (e.g., transmitted signals).

[0124] Various programs may be downloaded (i.e., transmitted as a transmission signal) from a server connected to a network not shown in the diagram and stored in flash memory, an HDD, etc. In this case, it is sufficient for the various programs to be stored in a non-temporary storage medium such as an HDD provided on the server. [Explanation of Symbols]

[0125] 1 Printing device 4 Display section LED 4A~4D 9. Transport motor 10 heads 21 CPU 25 Temperature Sensor 29 batteries 30 AC adapters 31 USB power supply unit 32 AC adapter jacks 33 USB jacks 34 Battery mounting section 100 Power supply circuit

Claims

1. A printing device that can be driven by multiple power sources, A print head that performs printing onto the medium, A transport motor that generates power for transporting the aforementioned medium, A first connection section to which the first power supply can be connected, A second connection section to which a second power supply can be connected, A first wiring that electrically connects the second connection part and the head, A second wiring that electrically connects the second connection part and the transport motor, A first switching unit that connects or disconnects the first wiring, A second switching unit that connects or disconnects the second wiring, A third wiring harness is provided to electrically connect the transport motor to the first wiring harness between the first switching unit and the head. A third switching unit that connects or disconnects the third wiring, A fourth wiring which electrically connects the first connection part to the first wiring between the first switching part and the head, A determination means for determining which of the multiple power sources is usable based on the conditions under which the multiple power sources are used, A power supply means that supplies power from the usable power source determined by the determination means to the head and the transport motor. Equipped with, The aforementioned power supply means is If the determination means determines that only one of the first power supply and the second power supply is usable, the power from the one power supply is supplied to the head and the transport motor. If the determination means determines that both the first power supply and the second power supply can be used, The first switching unit is shut off, and at least a portion of the first power, which is the power of the first power supply, is supplied to the head via the fourth wiring; the third switching unit is shut off, and the first power is not supplied to the transport motor. The second switching unit is made electrically conductive, and at least a portion of the second power, which is the power of the second power supply, is supplied to the transport motor via the second wiring. A printing apparatus characterized by the following features.

2. If the aforementioned determination means determines that none of the multiple power sources are available, printing will not be performed. The printing apparatus according to feature 1.

3. The aforementioned determination means is If the voltage output from the first power supply is equal to or greater than the first threshold, the first power supply is determined to be a usable power supply. If the voltage output from the second power supply is equal to or greater than the second threshold, the second power supply is determined to be a usable power supply. The printing apparatus according to claim 1 or 2.

4. The aforementioned first power source is a battery, The determination means determines that the battery is a usable power source if the voltage output from the battery is equal to or greater than a first threshold. The printing apparatus according to claim 1 or 2.

5. It is equipped with a third connection port to which a third power supply can be connected, The determination means determines that the battery is unusable if the voltage output by the battery is less than the first threshold. The aforementioned power supply means is If the aforementioned determination means determines that the battery is an unusable power source, and that the second power source and the third power source are usable power sources, At least a portion of the second power from the second power source is supplied to the head and the transport motor. At least a portion of the third power, which is the power from the third power source, is supplied to the battery. The printing apparatus according to feature 4.

6. The determination means determines that the third power supply is usable if it determines that the voltage output from the third power supply is equal to or greater than the third threshold. The printing apparatus according to feature 5.

7. The first threshold has a fourth threshold and a fifth threshold that is greater than the fourth threshold. The aforementioned determination means is If, among the aforementioned multiple power sources, all power sources other than the battery are unusable, and the voltage output from the battery is equal to or greater than the fourth threshold, the battery is determined to be a usable power source. If any of the aforementioned multiple power sources other than the battery are usable, and the voltage output from the battery is equal to or greater than the fifth threshold, the battery is determined to be a usable power source. A printing apparatus according to any one of features 4 to 6.

8. The system includes a detection unit that detects the temperature of each of the aforementioned multiple power supplies, The determination means determines that power supplies whose temperatures, as detected by the detection unit, fall within a predetermined temperature range are usable power supplies. A printing apparatus according to any one of features 1 to 7.

9. The determination means determines that, among the multiple power sources, the power source that can supply a current greater than the current required to drive the head and the current required to drive the transport motor is a usable power source. A printing apparatus according to any one of features 1 to 8.

10. It is equipped with a third connection port to which a third power supply can be connected, The aforementioned first power source is a battery, The aforementioned third power supply is a USB power supply unit, The aforementioned power supply means is If the current that can be supplied by the USB power supply unit is greater than the current required to drive the transport motor, and the voltage output by the USB power supply unit is greater than or equal to the sixth threshold, then the power from the USB power supply unit is supplied to the transport motor, and the first power from the battery is supplied to the head. If the current that can be supplied by the USB power supply unit is less than the current required to drive the transport motor, and the voltage output by the USB power supply unit is less than the sixth threshold, then the first power from the battery is supplied to the head and the transport motor. The printing apparatus according to feature 9.

11. A printing device that can be driven by multiple power sources, A print head that performs printing onto the medium, A transport motor that generates power for transporting the aforementioned medium, A first connection section to which the first power supply can be connected, A second connection section to which a second power supply can be connected, A determination means for determining which of the multiple power sources is usable based on the conditions under which the multiple power sources are used, A power supply means that supplies power from the usable power source determined by the determination means to the head and the transport motor, A detection unit for detecting the temperature of each of the aforementioned multiple power supplies Equipped with, The determination means determines that power supplies whose temperatures, as detected by the detection unit, fall within a predetermined temperature range are usable power supplies. The aforementioned power supply means is If the determination means determines that only one of the first power supply and the second power supply is usable, the power from the one power supply is supplied to the head and the transport motor. If the determination means determines that both the first power supply and the second power supply can be used, At least a portion of the first power, which is the power of the first power supply connected to the first connection part, is supplied to the head. At least a portion of the second power, which is the power of the second power supply connected to the second connection part, is supplied to the transport motor. A printing apparatus characterized by the following features.

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