Printing apparatus and

Abstract

To provide a printer which can be reduced in size by omitting a step-down circuit of power supplied to an external device based on a USB-PD standard.SOLUTION: The CPU acquires information on the power supply capability by negotiation with the source. The CPU obtains the required power by negotiation with the sink. The CPU requests the source for the power of the voltage value requested by the sink, which is the sum of the requested power of the sink and the power consumption of the control unit 50, and receives the power. The CPU turns on the FET41 to supply the power supplied from the source to the sink. Therefore, the printing apparatus 1 can supply the power received from the source to the sink without stepping down the voltage.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] The image processing device of Patent Document 1 includes a low-voltage power supply and a composite IC. The low-voltage power supply converts commercial power supplied from an external power source via a power plug into low-voltage DC power and supplies it to the composite IC. The composite IC converts the power supplied from the low-voltage power supply into a power pair of voltage and current required by an external device based on the USB-PD standard, and supplies the power to the external device via a USB interface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-144301 Summary of the Invention [Problem to be solved by the invention]

[0004] External devices require a variety of combinations of voltage and current values, so the composite IC must be able to supply power corresponding to each of these combinations of voltage and current values, requiring a step-down circuit for each combination, which results in an increase in the size of the device.

[0005] An object of the present invention is to provide a printing device that can be made smaller by eliminating a step-down circuit for power supplied to external devices based on the USB-PD standard. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a printing device comprising: a first USB connector connected to a power supply source; a second USB connector to which an external device is connected; a PD circuit configured to perform negotiation in accordance with the USB-PD standard between the power supply connected to the first USB connector and the external device connected to the second USB connector; a printing unit including a transport unit that transports a print medium and a print head that prints on the print medium and is powered by power supplied from the power supply source; and a processor that controls the PD circuit and the printing unit, wherein the processor performs the following operations: a first acquisition process that acquires supply information indicating the type of power level that the power supply source can supply; a second acquisition process that acquires request information indicating the amount of power that the external device requests to receive; a request process that requests the power supply source to supply compliant power, which is power of a magnitude that corresponds to the requested power, which is the amount of power that the external device requests to receive, from the power that the power supply source can supply and which is indicated in the supply information; and a supply process that supplies the compliant power supplied from the power supply source to the external device.

[0007] The printing device receives power corresponding to the power requirement of an external device connected to the second USB connector from a power supply source and supplies that power to the external device, thereby eliminating the need for a step-down circuit to reduce the power from a commercial power source according to the required power. This allows the printing device to reduce the size of its power supply circuit. The printing device also reduces heat generation that would otherwise occur if a step-down circuit were installed.

[0008] In this aspect, the processor executes a reception process to receive a print command instructing the printing unit to print. When the print command is received during the reception process, the processor instructs the PD circuit to re-negotiate with the power supply source and the external device. During the request process, the processor requests the power supply source to supply printing power, which is the amount of power required for printing by the printing unit. During the supply process, the printing power supplied from the power supply source may be supplied to the external device. When it becomes necessary to supply printing power to the printing unit in response to the print command, the printing device also supplies the external device with printing power. In other words, when supplying printing power to the printing unit, the printing device supplies printing power supplied from the power supply source without supplying the corresponding power to the external device. By omitting the implementation of step-down circuits for generating the printing power and the corresponding power from a commercial power source, the printing device can achieve a smaller power supply circuit.

[0009] In this aspect, the processor may request the supply source to supply the printing power in the request process when the external device is not connected to the second USB connector. By receiving printing power from the supply source when no external device is connected, the printing device can have the printing unit immediately execute printing when a print command is received.

[0010] In this aspect, if the amount of power requested by the external device indicated in the request information is greater than the amount of power the supply source indicated in the supply information can supply, the processor may request the supply source to supply printing power, which is the amount of power required for printing by the printing unit, in the request process, and may not supply power to the external device in the supply process. If the power requested by the external device is greater than the power the supply source can supply, the printing device cannot supply the power requested by the external device. In this case, the printing device may not supply power to the external device and may receive printing power from the supply source, thereby allowing the printing unit to immediately start printing when a print command is received.

[0011] This aspect may include a mounting unit for mounting a battery, and the processor, in the request process, requests the supply source to supply the corresponding power corresponding to the power required by the external device, and in the supply process, supplies the corresponding power supplied from the supply source to the external device. When the print command is received in the reception process, the processor causes the printing unit to receive the printing power from the battery and instructs the printing unit to print on the print medium. By receiving the power necessary for the operation of the printing unit from the battery, the printing device can supply the power supplied from the supply source to the external device. Therefore, the printing device can supply sufficient power to the external device and have the printing unit immediately execute printing upon receiving a print command.

[0012] In this aspect, when the external device is not connected to the second USB connector, the processor may request the supply source to supply charging power, which is the amount of power required to charge the battery, in the request process, and supply the charging power supplied from the supply source to the battery in the supply process.The printing device can charge the battery when no external device is connected.Therefore, the printing device does not distribute power from the supply source between the external device and the battery, so it can supply maximum power to the battery and charge the battery more quickly. [Brief explanation of the drawings]

[0013] [Figure 1] 2 is a block diagram showing the electrical configuration of the printing device 1. FIG. [Figure 2] FIG. 2 is a block diagram showing the power supply configuration of the printing device 1. [Figure 3] FIG. 1 is a diagram for explaining the power rules defined in USB-PD. [Figure 4] 10 is a flowchart (1 / 3) of a power receiving process. [Figure 5] 10 is a continuation of the flowchart (2 / 3) of the power supply and reception process. [Figure 6] 10 is a flowchart (3 / 3) illustrating the continuation of the power supply and reception process. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings are used to explain technical features that can be adopted by the present invention. In other words, the configurations and the like shown in the drawings are merely illustrative examples and are not intended to limit the present invention.

[0015] The electrical configuration of the printing device 1 will be described with reference to Figure 1. The printing device 1 is a thermal printer that is driven by power supplied from either an AC adapter 7 or a battery 9 and prints on a print medium. The print medium is, for example, a long print tape whose length in the transport direction is longer than its width.

[0016] The printing device 1 includes a housing 2. The housing 2 has a mounting section 3 and USB connectors 71 and 72 on its surface. A battery 9 is mounted in the mounting section 3. The battery 9 is, for example, a lithium-ion battery or an electric double-layer capacitor capable of outputting a voltage of 8.4 V. The USB connector 71 is a connection port for connecting a device that supplies power to the printing device 1 (power supply device), such as an AC adapter 7, via a USB cable 76 that conforms to the USB-PD (USB Power Delivery) standard. In the following description, a device that connects to the USB connector 71 and serves as a power supply source for supplying power to the printing device 1 from outside the printing device 1 is referred to as a "source." The USB connector 72 is a connection port for connecting a device that receives power from the printing device 1 (power supply destination device), such as an external device 8, via a USB cable 77 that conforms to the USB-PD standard. In the following description, a device that connects to the USB connector 72 and receives power from the printing device 1 is referred to as a "sink." The USB connectors 71 and 72 are connected to the I / O 57 via the I / O, and also relay data communication between the CPU 51 and external devices connected to the USB connectors 71 and 72 .

[0017] The source is not limited to the AC adapter 7, and may be, for example, a general-purpose personal computer, a mobile terminal, a tablet terminal, etc. The source supplies power to the printing device 1 in accordance with the power rules (see FIG. 3) of the USB-PD standard. The power rules are information that defines the power and voltage values ​​that the source can output according to a wattage called PDP (Power Delivery Power). In this embodiment, the voltage values ​​corresponding to the PDP of the source are 5V, 9V, 15V, and 20V. The source can output to the printing device 1 the power required by the printing device 1.

[0018] Examples of the external device 8 serving as the sink include various peripheral devices and accessories, such as general-purpose personal computers, mobile devices, tablet devices, smartphones, smartwatches, digital cameras, video cameras, game consoles, music players, mobile batteries, and storage devices. In this embodiment, the power that the printing device 1 can supply to the sink depends on the source, and is, for example, 5 V, 9 V, 15 V, or 20 V. The printing device 1 can output to the sink the power received from the source minus the power required to drive the control unit 50.

[0019] Inside the housing 2, there are provided a control unit 50, a printing unit 4, drive circuits 61 and 62, a charging circuit 63, and PD circuits 64 and 65. The control unit 50 includes a CPU 51, a ROM 52, a RAM 53, a bus 56, an input / output interface (hereinafter referred to as "I / O") 57, a flash memory 54, and a wireless communication interface (hereinafter referred to as "wireless communication IF") 55. The CPU 51 is electrically connected to each of the ROM 52, the RAM 53, and the I / O 57 via the bus 56.

[0020] The CPU 51 is a processor that controls the printing device 1. The ROM 52 stores various programs and the like. The various programs include commands that instruct the printing device 1 to execute various processes, including the power supply process described below, and are executed by the CPU 51. The RAM 53 temporarily stores flags, counters, calculation results, and the like. The flash memory 54 is connected to the I / O 57 and is electrically connected to the CPU 51 via the bus 56. The flash memory 54 stores various settings and the like for the printing device 1.

[0021] The wireless communication IF 55 is connected to the I / O 57 and electrically connected to the CPU 51 via a bus 56. The wireless communication IF 55 is a communication interface capable of performing short-range wireless communication conforming to the Bluetooth (registered trademark) standard, for example. The communication standard of the wireless communication IF 55 is not limited to the Bluetooth (registered trademark) standard, and may be other short-range wireless communication standards such as NFC. The wireless communication IF 55 may be configured to be able to communicate with an external device using, for example, the WFD (abbreviation for Wi-Fi Direct (registered trademark)) method established by the Wi-Fi Alliance.

[0022] The printing unit 4 includes a transport unit 5 and a print head 6. The transport unit 5 is a roller that transports the print medium in the transport direction. The print head 6 is a thermal head that is arranged on the transport path of the print medium and has multiple heating elements (not shown) aligned in the width direction of the print medium. The printing device 1 prints on the print medium by selectively heating the multiple heating elements of the print head 6 while transporting the print medium using the transport unit 5. The transport unit 5 and print head 6 have a predetermined rated voltage value. In this embodiment, the rated voltage value of the transport unit 5 and print head 6 is 5V.

[0023] Connected to the I / O 57 are drive circuits 61 and 62, a charging circuit 63, and PD circuits 64 and 65. The drive circuit 61 controls the drive of a motor (not shown) that rotates the transport unit 5 in response to instructions input from the CPU 51. The drive circuit 62 controls the drive of the heat generating elements of the print head 6 in response to instructions input from the CPU 51. The charging circuit 63 detects whether a battery 9 is attached to the attachment unit 3, and if attached, charges the battery 9 based on power supplied from a source connected to the USB connector 71. The PD circuits 64 and 65 are configured to execute negotiation in accordance with the USB-PD standard between the source and sink connected to the USB connectors 71 and 72. The PD circuits 64 and 65 are capable of communicating with the CPU 51.

[0024] The power supply configuration of the printing device 1 will be described with reference to FIG. 2. An AC adapter 7, for example, is connected to the USB connector 71 as a source. The source supplies power to the printing device 1 via the USB connector 71 by negotiating with the PD circuit 64 (see FIG. 1). The power is branched at branch points A and B and sent to the charging circuit 63, FETs 41 and 42, and OR circuit 45. The charging circuit 63 controls charging of the battery 9 according to the temperature, voltage, usage state, etc. of the battery 9. The FETs 41 and 42 are switching elements that switch ON and OFF according to instructions output from the control unit 50. When the FET 41 is ON, power is sent to the external device 8, which is the sink, via the USB connector 72. When the FET 41 is OFF, power transmission to the sink is stopped. When the FET 42 is ON, power is sent to the OR circuit 46. When the FET 42 is OFF, power transmission to the OR circuit 46 is stopped.

[0025] However, a step-down circuit for lowering the voltage of the power being transmitted is not provided in the power transmission path connecting the USB connector 71 to which the source is connected and the USB connector 72 to which the sink is connected. Therefore, when the FET 41 is ON, the power (voltage) supplied from the source is transmitted to the sink.

[0026] The OR circuit 45 switches the power transmission path to the control unit 50 and the printing unit 4 between a path that transmits power from the battery 9 and a path that transmits power from the source. The CPU 51 switches the power transmission path in the OR circuit 45 in conjunction with the execution of a power supply / reception process, which will be described later.

[0027] The power supplied by the OR circuit 45, which switches the supply source between the battery 9 or the source, is branched at a branch point C and sent to the 3.3V step-down circuit 48 and the FET 43. The control unit 50 consumes power with a voltage value of, for example, 3.3V as drive power. The 3.3V step-down circuit 48 is, for example, a switching regulator, and steps down the power supplied from the battery 9 or the source to 3.3V and supplies it to the control unit 50.

[0028] FET 43 is a switching element that, when ON, transmits power supplied from battery 9 or a source to 5V step-down circuit 47, and stops power transmission when OFF. 5V step-down circuit 47 is, for example, a switching regulator, and reduces the power supplied from battery 9 or a source to, for example, 5V 1.5A as driving power consumed in printing unit 4.

[0029] The 5V step-down circuit 47 transmits the stepped-down power to the OR circuit 46. The OR circuit 46 switches the power transmission path to the control unit 50 and the printing unit 4 between a path that transmits power from the battery 9 or source via the OR circuit 45 and a path that transmits power from the source via the FET 42. The CPU 51 switches the power transmission path in the OR circuit 46 in conjunction with the execution of a power supply / reception process, which will be described later. The power supplied by the OR circuit 46 after switching the power transmission path is branched at branch point D and transmitted to the transport unit 5 and print head 6 of the printing unit 4.

[0030] The power rules will be explained with reference to Figure 3. When a source is connected to the USB connector 71, the CPU 51 of the printing device 1 negotiates with the source using the PD circuit 64 to obtain a combination of voltage and current values ​​that can be supplied according to the source's PDP. The power rules specify fixed output combinations that must be implemented according to the USB-PD standard and are specific to the PDP. For example, if the source's PDP is 60W, the specifications stipulate that the source must be capable of outputting 5V 3A, 9V 3A, 15V 3A, and 20V 3A.

[0031] The USB-PD standard allows manufacturers to make proprietary extensions, allowing for power supply using combinations other than the fixed output combinations required by the power rules. For example, if the source PDP is 25W or higher, the source may be capable of supplying 5V5A power in addition to the required 5V3A fixed output. However, if a current value exceeding 3A is to be supplied, the source must first verify using an IC chip built into the cable that the USB cable being used is capable of carrying a current of 5A.

[0032] Next, the flow of processing in which the printing device 1 receives power from the source and supplies power to the sink will be described. The CPU 51 acquires a combination of voltage and current values ​​(hereinafter also referred to as power supply capacity) corresponding to the source's PDP, and requests the source for the power of the combination of voltage and current values ​​it desires to receive (hereinafter also referred to as requested power). If the source is able to supply the combination of voltage and current values ​​in response to the received request, it supplies the printing device 1 with the power of that voltage and current value (hereinafter also referred to as supported power).

[0033] Furthermore, when a sink is connected to the USB connector 72, the CPU 51 of the printing device 1 negotiates with the sink using the PD circuit 65 and transmits its power supply capability to the sink. The printing device 1 does not have a step-down circuit for stepping down the power supply voltage value supplied from the source. Therefore, the printing device 1 cannot, for example, receive power from the source at the maximum voltage value that the source can supply and then step down that power to generate and supply power to the sink that is a fixed output combination required by the power rule.

[0034] Therefore, the printing device 1 transmits the power supply capacity of the source to the sink. The printing device 1 then requests the source for the power (requested power) of the combination of voltage and current values ​​required by the sink, and receives the power (corresponding power) of that voltage and current value from the source. The printing device 1 supplies the power received from the source to the sink as power corresponding to the sink's request. Note that, in order to satisfy the required combination of fixed outputs defined in the power rules, the printing device 1 receives from the source the power it supplies to the sink plus the power consumed by the control unit 50.

[0035] The power receiving process executed by the CPU 51 will be described with reference to Figures 2 and 4 to 6. Hereinafter, step will be abbreviated as S. The power receiving process is a process in which the printing device 1 receives power from a source and supplies power to a sink. At the start of the power receiving process, all of the FETs 41 to 43 are OFF.

[0036] As shown in Fig. 4, prior to the execution of the power receiving process, when a source (AC adapter 7) is connected to the USB connector 71 (S11), the PD circuit 64 starts negotiation with the source (S12). The PD circuit 64 acquires the power supply capability of the source from the source. The PD circuit 64 requests the source to supply 5V power and starts receiving power from the source (S13). The above process is an initial operation performed to acquire power for operating the control unit 50 when a source is first connected to the USB connector 71.

[0037] When power is supplied to the printer 1 from the source at 5V, the control unit 50 receives power stepped down to 3.3V and begins operating. At this time, the OR circuit 45 is set to close the power transmission path from the battery 9 and open the power transmission path from the source. After the printer 1 is powered on, the CPU 51 reads into the RAM 53 a program for executing a power receiving process stored in the ROM 52. The CPU 51 executes the power receiving process, which has the following steps, in accordance with instructions contained in the program read into the RAM 53 (S14). Various data obtained during the power receiving process is stored in the RAM 53 as appropriate.

[0038] The CPU 51 inquires of the PD circuit 65 whether or not a sink (external device 8) is connected to the USB connector 72. If a sink is not connected (S16: NO), the CPU 51 proceeds to S41 (described below). If a sink is connected (S16: YES), the CPU 51 proceeds to S21.

[0039] As shown in FIG. 5, the PD circuit 65 negotiates with the sink and receives a power request from the sink. The CPU 51 acquires information about the power requested by the sink from the PD circuit 65 (S21). Based on the information about the source's power supply capability acquired by the PD circuit 64 and the information about the power requested by the sink, the CPU 51 confirms whether the source can supply the power requested by the sink. That is, the CPU 51 confirms whether the source's PDP is equal to or greater than the sum of the power requested by the sink and the power consumed by the control unit 50 (S22). For example, if the sink requests 15V 3A (45W) of power, the source needs a PDP of 46.65W or more, which is the sum of the power consumed by the control unit 50, for example, 3.3V 0.5A (1.65W). Therefore, if the source can supply the power requested by the sink (S22: YES), the CPU 51 instructs the PD circuit 64 to renegotiate with the source. The PD circuit 64 receives from the source a supply of power (corresponding power) that satisfies the sum of the power required by the sink and the power consumption of the control unit 50. In this case, the PD circuit 64 sets the voltage value of the power supplied from the source to the same voltage value as the voltage value required by the sink, and starts receiving power (S23).

[0040] The CPU 51 turns on the FET 41 to start supplying power to the sink (S24). The power supplied from the source is supplied from branch point A through the FET 41 to the sink connected to the USB connector 72. The power supplied from the source passes from branch point B through the OR circuit 45, and from branch point C through the 3.3V step-down circuit 48, where it is stepped down to 3.3V and supplied to the control unit 50. On the other hand, if the source cannot supply the power required by the sink in S22 (S22: NO), the CPU 51 shifts the process to S26 and does not supply power to the sink.

[0041] While the connection with the sink is maintained (S26: YES), the CPU 51 waits for reception of print data (S27: NO). When print data is received from the external device 8 connected via the USB cable 77 or from the external device connected via the wireless communication IF 55 (S27: YES), the CPU 51 inquires of the charging circuit 63 whether the battery 9 is connected (S28). When the battery 9 is attached to the attachment unit 3 and connected to the battery 9 (S28: YES), the CPU 51 turns on the FET 43. The OR circuits 45 and 46 are set to close the power transmission path from the source and open the power transmission path from the battery 9. The source maintains power supply to the sink via the FET 41. The control unit 50 and the printing unit 4 are supplied with power from the battery 9, which has been stepped down to 3.3V and 5V by the 3.3V step-down circuit 48 and the 5V step-down circuit 47, respectively. The CPU 51 drives the printing unit 4 using power from the battery 9 as printing power, outputs a print command to the printing unit 4, and performs printing according to the print data (S29). After printing, the CPU 51 turns off the FET 43, returns the process to S26, and waits for reception of print data.

[0042] In S28, if the charging circuit 63 is not connected to the battery 9 and the battery 9 is not attached to the attachment portion 3 (S28: NO), the CPU 51 turns off the FET 41 to close the power transmission path from the source to the sink and stop power supply to the sink (S31). The CPU 51 issues a command to the PD circuit 64 to have the PD circuit 64 renegotiate with the source. The PD circuit 64 requests the source to supply 5V 5A power and starts receiving power (S32). The OR circuits 45 and 46 are set to close the power transmission path from the battery 9 and open the power transmission path from the source. The CPU 51 has the PD circuit 65 renegotiate with the sink (S33) and obtains information about the power requested by the sink from the PD circuit 65. If the power required by the sink is 5V (fixed) 3A or less (S34: YES), the sum of the power consumed by the control unit 50 (3.3V 0.5A), the power consumed by the printing unit 4 (5V 1.5A), and the power supplied to the sink (5V 3A or less) is 5V 5A or less, and voltage step-down is not necessary, so the CPU 51 turns on FET 41 and starts supplying power to the sink (S36).On the other hand, if the power required by the sink is not 5V 3A or less (S34: NO), the CPU 51 proceeds to S37 and does not supply power to the sink.

[0043] The CPU 51 turns on the FET 42. The printing unit 4 is supplied with 5V power from the source. The CPU 51 drives the printing unit 4 using the power from the source as printing power, outputs a print command to the printing unit 4, and performs printing according to the print data (S37). After printing, the CPU 51 turns off the FET 42 and returns the process to S21. Therefore, even if the power requested by the sink is greater than 5V 3A, the PD circuit 64 renegotiates with the source to reset the voltage value of the power supplied from the source to the same voltage value as the voltage value requested by the sink, and supplies power to the sink (S21 to S24).

[0044] If the USB cable 77 is unplugged from the USB connector 72 and the connection with the sink is interrupted while waiting to receive print data (S26: NO), the CPU 51 instructs the PD circuit 64 to renegotiate with the source. The PD circuit 64 requests the source to supply 5V 3A power and starts receiving power (S39). The CPU 51 proceeds to S41. FETs 41 to 43 are all set to OFF.

[0045] As shown in FIG. 6, the CPU 51 inquires of the charging circuit 63 whether there is a connection to the battery 9 (S41). If the battery 9 is attached to the attachment unit 3 and there is a connection to the battery 9 (S41: YES), the CPU 51 issues a command to the PD circuit 64 to cause the PD circuit 64 to renegotiate with the source. The PD circuit 64 requests the source to supply 15V 3A power that is sufficient to charge the battery 9, and starts receiving power (S42). The OR circuit 45 is set to close the power transmission path from the battery 9 and open the power transmission path from the source. Therefore, the control unit 50 is supplied with power from the source that has been stepped down to 3.3V by the 3.3V step-down circuit 48.

[0046] The CPU 51 issues an instruction to the charging circuit 63 to start charging the battery 9 (S43). The charging circuit 63 controls the charging of the battery 9, suspending charging when the battery 9 is fully charged (8.4 V) and resuming charging when the voltage drops below a predetermined value.

[0047] While the battery 9 is being charged, the CPU 51 waits until a sink is connected to the USB connector 72 or until print data is received (S44: NO, S46: NO). If print data is received while the battery 9 is being charged (S46: YES), the CPU 51 instructs the charging circuit 63 to stop charging the battery 9 (S47). The CPU 51 instructs the PD circuit 64 to renegotiate with the source. The PD circuit 64 requests the source to supply 5V 3A power and begins receiving power (S48). The CPU 51 turns on FET 42 to open the power transmission path from the source to the printing unit 4. The OR circuit 46 is also set to open the power transmission path from the source via FET 42. The printing unit 4 is supplied with 5V 2.5A power from the source. The CPU 51 uses the power from the source as printing power to drive the printing unit 4, outputs a print command to the printing unit 4, and prints according to the print data (S49). After printing, the CPU 51 turns off the FET 42 and returns the process to S42. 15V power is supplied from the source (S42), and charging of the battery is resumed (S43).

[0048] If a sink is connected to the USB connector 72 while the battery 9 is being charged (S44: YES), the CPU 51 issues an instruction to the charging circuit 63 to stop charging the battery 9 (S56). The CPU 51 shifts the process to S21. The PD circuit 64 renegotiates with the source, resets the voltage value of the power supplied from the source to the same voltage value requested by the sink, and supplies power to the sink (S21 to S24).

[0049] If no sink is connected to the printer 1 (S26: NO) and the battery 9 is not installed (S41: NO), the CPU 51 waits until a sink is connected to the USB connector 72 or until print data is received (S51: NO, S52: NO). Note that 5V power is supplied to the printer 1 from the source. If print data is received during standby (S52), the CPU 51 turns on FET 42. 5V power is supplied from the source to the printing unit 4. The CPU 51 uses the power from the source as printing power to drive the printing unit 4, outputs a print command to the printing unit 4, and performs printing according to the print data (S53). After printing, the CPU 51 turns off FET 42 and returns the process to S51.

[0050] During standby, if the USB cable 77 is inserted into the USB connector 72 and connected to the sink (S51: YES), the CPU 51 proceeds to S21. The PD circuit 64 renegotiates with the source to reset the voltage value of the power supplied from the source to the same voltage value requested by the sink, and supplies power to the sink (S21 to S24). While the connection with the sink is maintained (S26: YES), the CPU 51 waits to receive print data (S27: NO).

[0051] As described above, the printing device 1 receives from the AC adapter 7 the power required by the external device 8 connected to the USB connector 72, and supplies that power to the external device 8, thereby eliminating the need to install a step-down circuit to reduce the power from the commercial power source according to the required power. This allows the printing device 1 to have a more compact power supply circuit. The printing device 1 also reduces heat generation that can occur when a step-down circuit is installed.

[0052] When print data is received and it becomes necessary to supply printing power to the printing unit 4, the printing device 1 also supplies the external device 8 with printing power. In other words, when supplying printing power to the printing unit 4, the external device 8 is not supplied with compliant power, but is instead supplied with printing power supplied from the AC adapter 7. By omitting the implementation of step-down circuits for generating printing power and compliant power from a commercial power source, the printing device 1 can achieve a more compact power supply circuit.

[0053] When the external device 8 is not connected, the printing device 1 receives printing power from the AC adapter 7, so that the printing unit 4 can immediately start printing when a print command is received.

[0054] If the power required by the external device 8 is greater than the power that the AC adapter 7 can supply, the printing device 1 cannot supply the power requested by the external device 8. In this case, the printing device 1 does not supply power to the external device 8, but receives printing power from the AC adapter 7, thereby allowing the printing unit 4 to immediately start printing when a print command is received.

[0055] By receiving the power required for the operation of the printing unit 4 from the battery, the printing device 1 can supply the power supplied from the AC adapter 7 to the external device 8. Therefore, the printing device 1 can have the printing unit 4 execute printing immediately upon receiving a print command while supplying sufficient power to the external device 8.

[0056] The printing device 1 can charge the battery when no external device 8 is connected. Therefore, the printing device 1 does not distribute power from the AC adapter 7 between the external device 8 and the battery, so it can supply maximum power to the battery and charge the battery more quickly.

[0057] In the above embodiment, the AC adapter 7 is an example of a "supply source" of the present invention. The USB connector 71 is an example of a "first USB connector" of the present invention. The external device 8 is an example of an "external device" of the present invention. The USB connector 72 is an example of a "second USB connector" of the present invention. The PD circuits 64 and 65 are an example of a "PD circuit" of the present invention. The CPU 51 is an example of a "processor" of the present invention. The power supply capacity is an example of "supply information" of the present invention. The processing of S12 is an example of a "first acquisition processing" of the present invention. The requested power is an example of "request information" of the present invention. The processing of S21 is an example of a "second acquisition processing" of the present invention. The processing of S23 is an example of a "request processing" of the present invention. The processing of S24 is an example of a "supply processing" of the present invention. The processing of S27 is an example of a "receiving processing" of the present invention. The power capable of charging the battery 9 is an example of "charging power" of the present invention.

[0058] The present invention may be modified from the above embodiment. The various modifications described below may be combined with each other as long as no contradictions arise. The printing device 1 may not have the mounting unit 3. In this case, the battery 9 may be built into the housing 2 and not be removable. The FETs 41 to 43 are not limited to switching elements and may be relay switches, for example. A program including instructions for the CPU 51 to execute processing is stored in the ROM 52, but may also be stored in the flash memory 54.

[0059] The power transmission and reception between the source and sink is performed according to the power rules defined in USB-PD, but may also be performed according to a power profile. In S36, power is supplied to the sink when the battery 9 is not installed and the sink's required power is 5V 3A or less, but power supply to the sink may be stopped during printing. [Explanation of symbols]

[0060] 1 Printing device 3. Mounting part 4 Printing Department 5. Conveyor 6 print heads 7 AC adapter 8 External equipment 9 Battery 50 control section 51 CPU 64,65 PD circuit 71,72 USB connector

Claims

1. a first USB connector for connection to a source of power; a second USB connector to which an external device is connected; a PD circuit configured to execute negotiation according to the USB-PD standard between the power supply connected to the first USB connector and the external device connected to the second USB connector; a printing unit that includes a transport unit that transports a print medium and a print head that prints on the print medium, and is driven by power supplied from the power supply; a processor that controls the PD circuit and the printing unit; Equipped with The processor: a first acquisition process for acquiring supply information indicating the type of magnitude of power that the power supply source can supply; a second acquisition process for acquiring request information indicating the amount of power that the external device requests to receive; a request process for requesting the supply source to supply corresponding power, which is power of a magnitude corresponding to requested power, which is power of a magnitude requested to be received by the external device, which is indicated in the request information, from the power that the supply source indicated in the supply information can supply; a supply process of supplying the corresponding power supplied from the power supply source to the external device; To carry out A printing device comprising:

2. The processor: executes a receiving process for receiving a print command instructing the printing unit to perform printing; When the print command is received in the receiving process, the PD circuit is instructed to execute re-negotiation with the supply source and the external device; In the request process, a request is made to the supply source for a printing power supply, the power being a power required for printing by the printing unit; In the supply process, the printing power supplied from the supply source is supplied to the external device.

2. The printing device according to claim 1, wherein:

3. The processor: When the external device is not connected to the second USB connector, In the request process, a request is made to the supply source to supply the printing power.

3. The printing device according to claim 2, wherein:

4. The processor: When the amount of power requested by the external device indicated in the request information is greater than the amount of power that can be supplied by the power supply source indicated in the supply information, In the request process, a request is made to the supply source for a printing power supply, the power being a power required for printing by the printing unit; In the supply process, power is not supplied to the external device.

2. The printing device according to claim 1, wherein:

5. a mounting portion for mounting a battery; The processor: In the request process, a request is made to the power supply source to supply the corresponding power corresponding to the requested power of the external device; In the supply process, the corresponding power supplied from the power supply source is supplied to the external device; When the print command is received in the receiving process, the print unit is instructed to receive the print power from the battery and to print on the print medium.

3. The printing device according to claim 2, wherein:

6. The processor: When the external device is not connected to the second USB connector, In the request process, a request is made to the supply source for supply of charging power, which is power of a magnitude required to charge the battery; In the supply process, the charging power supplied from the supply source is supplied to the battery.

6. The printing device according to claim 5,

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