printer

Abstract

Provided is a printer that, when the printer has a function of feeding power to an external device, is capable of maintaining a printing operation even if the load on a power source increases.　The printer comprises: a printing unit; a power feeding unit; and a CPU. The printing unit can execute a printing operation on a medium on the basis of power from the power source. The power feeding unit can feed power to an external device on the basis of power from the power source. The CPU acquires a parameter indicating the magnitude of the load on the power source when being supplied with power from the power source (S3). When the acquired parameter is equal to or more than a first prescribed value, the CPU limits the feeding of the power from the power feeding unit to the external device (S13).

Description

printer

[0001] The present invention relates to a printer.

[0002] The printer in Patent Document 1 performs its main functions, such as printing, using power from an AC adapter. The printer includes a temperature detector, a temperature monitoring unit, and a printing condition setting unit. The temperature detector detects the surface temperature of the AC adapter. The temperature monitoring unit monitors the surface temperature detected by the temperature detector. When the surface temperature falls within a predetermined warning temperature range, the temperature monitoring unit specifies printing control conditions to reduce the printing load according to the surface temperature. The printing condition setting unit outputs control information according to the specified printing control conditions to the printing control unit and the transport control unit. The printing control unit and the transport control unit perform printing control based on the output control information.

[0003] Japanese Patent Application Laid-Open No. 2006-102962

[0004] If the printer is equipped with a function to supply power to external devices, the printer will perform printing operations while also supplying power to the external devices. In this case, the load on the AC adapter increases, so the printer will reduce the load of the printing operation by slowing down the printing speed, etc. As a result, the printer will not be able to maintain the scheduled printing operation.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a printer that has a function of supplying power to external devices and that can maintain printing operations even when the load on the power supply increases.

[0006] The printer of the present invention is a printer driven by a power source and includes a printing unit capable of printing on a medium based on the power of the power source, a power supply unit capable of supplying power to an external device based on the power of the power source, and a control unit, wherein the control unit executes an acquisition process to acquire a parameter indicating the magnitude of the load on the power source when power is supplied from the power source, and a first restriction process to restrict power supply from the power supply unit to the external device if the parameter acquired by the acquisition process becomes equal to or greater than a first predetermined value.

[0007] The printer ensures sufficient power for the printer's printing operation by limiting the power supply to external devices according to the load on the power supply. Therefore, the printer does not need to reduce the load required for printing. Therefore, if the printer has the power supply function for external devices, it can continue printing even if the load on the power supply increases.

[0008] In the present invention, the control unit may execute a second limiting process to limit the power consumed by the printing unit from the power source when the parameter acquired by the acquisition process reaches a second predetermined value that is equal to or greater than the first predetermined value. When the load on the battery becomes even greater, the printer can maintain printing operations by limiting the power consumed by the printing unit.

[0009] In the present invention, the second limiting process may limit the power consumed by the printing unit by slowing down the printing speed of the printing operation being performed by the printing unit to a second printing speed that is slower than the first printing speed, allowing the printer to maintain the printing operation while reducing the load on the power supply through simple control.

[0010] In the present invention, the control unit may execute at least one of a third limiting process that limits the power consumed by the printing unit by slowing down to a third printing speed slower than the second printing speed when the parameter reaches a third predetermined value that is equal to or greater than the second predetermined value, and a fourth limiting process that limits the power consumed by the printing unit by performing the printing operation at a second print density that is lighter than the first print density in the printing operation being performed by the printing unit when the parameter reaches or exceeds the third predetermined value.By slowing down to the third printing speed or lightening the print density to the second print density, the printer can maintain the printing operation while further reducing the load on the power supply.

[0011] In the present invention, the control unit may execute a first acceleration process to accelerate from the third printing speed to the second printing speed if the parameter falls below a fourth predetermined value that is equal to or less than the third predetermined value after limiting the power consumed by the printing unit through the third limiting process, and a first density restoration process to restore the print density from the second printing density to the first printing density if the parameter falls below the fourth predetermined value after limiting the power consumed by the printing unit through the fourth limiting process. When the load on the power supply is reduced, the power that can be consumed by the printing unit increases. In this case, the printer executes printing operations by accelerating to the second printing speed before the limiting process or restoring to the first printing density. Therefore, the printer can use the power of the power supply efficiently.

[0012] In the present invention, the third predetermined value and the fourth predetermined value may be different from each other. By setting each predetermined value to a different value, the printer can perform a stable printing operation.

[0013] In the present invention, the control unit may execute a second acceleration process to accelerate from the second printing speed to the first printing speed if the parameter becomes equal to or less than a fifth predetermined value that is equal to or less than the second predetermined value after limiting the power consumed by the printing unit through the second limiting process. When the load on the power supply becomes lighter, the power that can be consumed by the printing unit increases. In this case, the printer accelerates to the first printing speed before the limiting process and executes the printing operation. Therefore, the printer can use the power of the power supply efficiently.

[0014] In the present invention, the second predetermined value and the fifth predetermined value may be different from each other. By setting each predetermined value to a different value, the printer can perform a stable printing operation.

[0015] In the present invention, the second limiting process may limit the power consumed by the printing unit by executing the printing operation at a third print density that is lighter than the first print density of the printing operation currently being executed by the printing unit. The printer can maintain the printing operation while reducing the load on the power supply through simple control.

[0016] In the present invention, the control unit may execute at least one of a third limiting process that limits the power consumed by the printing unit by executing the printing operation at a fourth print density that is lighter than the third print density when the parameter reaches a third predetermined value that is equal to or greater than the second predetermined value, and a fourth limiting process that limits the power consumed by the printing unit by slowing down the printing speed to a fourth print speed that is slower than the first print speed of the printing operation being executed by the printing unit when the parameter reaches or exceeds the third predetermined value. By lightening the printing speed to the fourth print density or slowing down the printing speed to the fourth print speed, the printer can maintain the printing operation while further reducing the load on the power supply.

[0017] In the present invention, the control unit may execute a second density restoration process to restore the fourth print density to the third print density if the parameter falls below a fourth predetermined value, which is equal to or less than the third predetermined value, after limiting the power consumed by the printing unit through the third restriction process, and a third acceleration process to accelerate the fourth print speed to the first print speed if the parameter falls below the fourth predetermined value after limiting the power consumed by the printing unit through the fourth restriction process. When the load on the power supply is reduced, the power that can be consumed by the printing unit increases. In this case, the printer executes printing operations by restoring the third print density to the value before the restriction or accelerating to the first print speed. This allows the printer to use the power of the power supply efficiently.

[0018] In the present invention, the third predetermined value and the fourth predetermined value may be different from each other. By setting each predetermined value to a different value, the printer can perform a stable printing operation.

[0019] In the present invention, the control unit may execute a third density restoration process to restore the third print density to the first print density if the parameter falls below a fifth predetermined value that is equal to or less than the second predetermined value after limiting the power consumed by the printing unit through the second limitation process. When the load on the power supply is reduced, the power that can be consumed by the printing unit increases. In this case, the printer returns to the first print density before the limitation and executes the printing operation. Therefore, the printer can use the power of the power supply efficiently.

[0020] In the present invention, the second predetermined value and the fifth predetermined value may be different from each other. By setting each predetermined value to a different value, the printer can perform a stable printing operation.

[0021] In the present invention, the control unit may execute a release process to release the restriction on power supply to the external device imposed by the first limiting process when, after limiting power supply from the power supply unit to the external device through the first limiting process, the parameter falls to a sixth predetermined value that is equal to or less than the first predetermined value and the printing operation by the printing unit is completed. When the load on the power supply becomes lighter, the power that can be consumed by the printer increases. In this case, the printer resumes limiting power supply to the external device. This allows the printer to use the power supply efficiently. Furthermore, because the printer maintains the limit on power supply to the external device until the printing operation is completed, changes in the printer's operating state during printing can be suppressed. This allows the printer to maintain print quality.

[0022] In the present invention, the first predetermined value and the sixth predetermined value may be different from each other. By setting each predetermined value to a different value, the printer can perform a stable printing operation.

[0023] In the present invention, the power supply may be an AC adapter, and the printer can maintain printing operations even when the load on the AC adapter becomes large.

[0024] In the present invention, the power source may be a battery, and the printer can maintain printing operations even when the load on the battery becomes large.

[0025] In the present invention, the control unit may execute a load estimation process to estimate the parameters based on image data printed on the medium by the printing unit, and the acquisition process may acquire the parameters estimated by the load estimation process. Because the printer estimates the parameters, there is no need to provide a separate sensor, such as a temperature sensor, for detecting the load on the power supply.

[0026] In the present invention, the power supply may be provided with a sensor that measures the temperature of the power supply. The printer directly detects the temperature of the power supply with the sensor and uses the measurement result as a parameter, allowing for more accurate timing of limiting power consumption compared to when the load is estimated.

[0027] 1 is a diagram showing a connection state between the printer 1 and a tablet PC 5. FIG. 2 is a block diagram showing the electrical configuration of the printer 1. FIG. 3 is a flowchart of the main processing. FIG. 4 is a flowchart of the main processing, a continuation of FIG. 3. FIG. 5 is an image diagram of image data. FIG. 6 is a table showing transitions in the driving conditions of the printer 1. FIG. 7 is a diagram showing the relationship between the parameter P and each of the predetermined values ​​Th1 to Th6. FIG. 8 is a diagram showing the relationship between the parameter P and each of the predetermined values ​​Th1 to Th6 in a modified example.

[0028] The following description of an embodiment of the present invention will be made with reference to the accompanying drawings. The right-downward, left-upward, right-upward, left-downward, upward, and downward directions in FIG. 1 correspond to the right, left, rear, front, upper, and lower sides of the printer 1, respectively.

[0029] As shown in FIG. 1, the printer 1 is configured to be capable of printing on a print medium. The medium is, for example, a plurality of thermal labels continuously affixed to a long backing sheet. The printer 1 can be powered by an external power source connected to, for example, a commercial outlet (not shown). The external power source is, for example, an AC adapter 9 (see FIG. 2). The AC adapter 9 is connected to an attachment section 41 provided at the rear lower part of the right side of the printer 1. The printer 1 can also be powered by a battery 11 (see FIG. 2). The battery 11 is detachably attached to an attachment section 42 (see FIG. 2) provided inside the printer 1. The battery 11 is, for example, a lithium-ion secondary battery.

[0030] An interface 43 is provided at the lower front of the right side of the printer 1. The interface 43 is a USB interface (I / F) that complies with the USB Type-C (registered trademark) standard. A cable 3 is connected to the interface 43. The cable 3 has a connector that complies with the USB Type-C standard and supports USB PD (USB Power Delivery). For example, the cable 3 can transmit power corresponding to a current of up to 5 A and transmit various types of information.

[0031] The printer 1 can be connected to, for example, an external device via the interface 43 and the cable 3. The external device is, for example, a tablet PC 5. The tablet PC 5 is equipped with, for example, an LCD touch panel. A user edits image data such as text and graphics on the touch panel and sends the image data to the printer 1 via the cable 3. The printer 1 prints characters such as text and graphics on a medium based on the image data received from the external device.

[0032] The printer 1 is also capable of supplying power to the tablet PC 5 in accordance with the USB PD (USB Power Delivery) standard, thereby enabling the printer 1 to charge the tablet PC 5.

[0033] The electrical configuration of the printer 1 will be described with reference to Figure 2. The printer 1 further includes a charging IC 31, an OR circuit 32, a DCDC power supply 33, a digital circuit unit 6, a printing unit 7, and a power supply unit 8. The charging IC 31 charges the battery 11 attached to the attachment unit 42 using power from the AC adapter 9. The battery 11 includes a sensor 11A that can detect the battery temperature. The output result from the sensor 11A is sent to the CPU 21. The CPU 21 detects the temperature of the battery 11 from the received output result.

[0034] The OR circuit 32 switches the power supply path to the tablet PC 5 depending on whether the battery 11 and the AC adapter 9 are connected. For example, when only the AC adapter 9 is connected, the OR circuit 32 switches the power supply path so that power is supplied from the AC adapter 9. For example, when only the battery 11 is connected, the OR circuit 32 switches the power supply path so that power is supplied from the battery 11. When the AC adapter 9 and the battery 11 are connected, the OR circuit 32 switches the power supply path so that power from the AC adapter 9 is supplied to the battery 11, while supplying power from the AC adapter 9 to the digital circuit unit 6, the printing unit 7, the power supply unit 8, etc. Note that the switching of the power supply path by the OR circuit 32 is performed automatically, but may be set by the user.

[0035] The DCDC power supply 33 converts the input voltage from the AC adapter 9 or the battery 11 into an output voltage (e.g., 3.3 V) for driving the digital circuit unit 6. The digital circuit unit 6 includes a CPU 21, a RAM 22, a flash memory 23, an EEPROM 24, etc. The CPU 21 performs overall control of the printer 1. The CPU 21 is electrically connected to the RAM 22, the EEPROM 24, the flash memory 23, the printing unit 7, and the power supply unit 8.

[0036] The RAM 22 temporarily stores various data such as image data received from the tablet PC 5. The EEPROM 24 stores information such as printer settings and print history. The flash memory 23 stores various programs executed by the CPU 21 to control the printer 1.

[0037] The flash memory 23 stores a first predetermined value Th1 to a sixth predetermined value Th6, which are used as thresholds in the main processing described below. Each of the predetermined values ​​Th1 to Th6 is a value based on, for example, the rated current of the AC adapter 9, and may be set as appropriate. The first predetermined value Th1 to the sixth predetermined value Th6 are different from one another. For example, the relationship is first predetermined value Th1 < second predetermined value Th2 < third predetermined value Th3. The relationship is fourth predetermined value Th4 > fifth predetermined value Th5 > sixth predetermined value Th6. Furthermore, the relationship is third predetermined value Th3 > fourth predetermined value Th4. The relationship is second predetermined value Th2 > fifth predetermined value Th5. The relationship is first predetermined value Th1 > sixth predetermined value Th6. Details of each of the predetermined values ​​Th1 to Th6 will be described later.

[0038] The flash memory 23 stores a table showing the operating conditions of the printer 1, as shown in FIG. 6. For example, the operating conditions of the printer 1 refer to the operating conditions of the printing unit 7 and the power supply unit 8. The operating conditions of the printer 1 include the printing speed of the printing unit 7 when a print operation is performed, or the print density of an image printed on a medium. The operating conditions of the printer 1 include the on / off state of the power supply from the power supply unit 8 to the external device. The operating conditions of the printing unit 7 and the power supply unit 8 are changed based on the relationship between a parameter P, which will be described later, and each of the predetermined values ​​Th1 to Th6. The operating conditions are classified into cases A to D. Which of cases A to D is executed may be set automatically by the printer 1 or may be set by the user. Details will be described later.

[0039] Power from the AC adapter 9 or battery 11 is supplied to the printing unit 7. The printing unit 7 can print on a medium based on the power from the AC adapter 9 or battery 11. The printing unit 7 includes a thermal head 13 and a transport motor 15. The thermal head 13 generates heat in response to a signal from the CPU 21 and prints on the medium. The transport motor 15 drives a feed roller for feeding the medium. The CPU 21 controls the thermal head 13 and the transport motor 15 to print on the medium.

[0040] The power supply unit 8 includes a DCDC power supply 35, a USB PD IC 37, an FET 36, an interface 43, etc. The DCDC power supply 35 converts the input voltage from the AC adapter 9 or the battery 11 into an output voltage (e.g., 9 V, 5 V, etc.) suitable for supplying power to the tablet PC 5. Power from the power supply unit 8 is supplied to the tablet PC 5. The USB PD IC 37 is capable of mutual communication with the CPU 21. The USB PD IC 37 is capable of controlling the value of the output voltage from the DCDC power supply 35. The USB PD IC 37 executes negotiation with the tablet PC 5 via the interface 43 in accordance with the USB PD (USB Power Delivery) standard. The USB PD IC 37 controls the power supply from the DCDC power supply 35 to the tablet PC 5 by controlling the on / off of the FET 36. For example, when the FET 36 is turned on, power is supplied to the tablet PC 5 via the interface 43 and the cable 3. In other words, the power supply unit 8 can supply power to the tablet PC 5 based on the power of the AC adapter 9 or the battery 11.

[0041] The main processing will be described with reference to Figures 3 and 4. The following description will be given on the assumption that the printer 1 is driven by power from an AC adapter 9 as an external power source. A battery 11 may or may not be attached to the printer 1. It is assumed that a tablet PC 5 is connected to the printer 1 as an external device. When a user presses the power button on the printer 1, the CPU 21 reads and executes a program from the flash memory 23. This causes the CPU 21 to start the main processing.

[0042] When the main process starts, the CPU 21 determines whether image data has been acquired (S1). If it determines that image data has not been acquired (S1: NO), the CPU 21 returns to the process and waits. For example, a user operates the tablet PC 5, which is an external device, to edit image data and send it to the printer 1.

[0043] If it is determined that image data has been acquired (S1: YES), the CPU 21 acquires a parameter P (S3). The parameter P indicates the magnitude of the load on the AC adapter 9 when power is supplied from the AC adapter 9. The magnitude of the load is, for example, the magnitude of the current required to drive the printing unit 7. The parameter P is calculated, for example, by the CPU 21.

[0044] The estimation of the parameter P will be described in detail with reference to Figure 5. Image data is composed of, for example, N columns. When calculating the parameter P, the calculation is performed using, for example, image data for R columns out of the N columns. For example, if R = 3, that is, if the number of target lines is three, the calculation is performed based on the number of ON dots when printing the three target lines. The three target lines are, for example, lines 1 to 3.

[0045] For example, suppose the current required to print each line is 1 A, 1.5 A, and 0.2 A. The total current is 2.7 A. If the time required to print one line is 100 μsec, the average current value per unit time required to print one line is 2.7 / (100×3) = 0.009 A / μsec.

[0046] Thereafter, the average current value per unit time is similarly calculated based on the number of ON dots of the next three lines that were not subject to calculation. The next three lines to be calculated are, for example, lines 4 to 6. For example, assume that the average current value per unit time is 0.04 A. In this case, the integrated average value is (0.009 + 0.04) / 2 = 0.0245. This integrated average value is the parameter P. Thereafter, the parameter P is updated by calculating the integrated average value based on the average current values ​​of the next three lines to be calculated. The updated parameter P is temporarily stored in RAM 22.

[0047] The CPU 21 determines whether to maintain the printer 1's operating conditions based on the acquired parameter P (S5). For example, if there are no restrictions on the printer 1's operating conditions, the printer 1's operating conditions are maintained. It is also possible that, even if there are restrictions on the printer 1's operating conditions, the value of the acquired parameter P has not changed across the predetermined values ​​Th1 to Th6 that will be the next targets for changing the restrictions. In this case, the printer 1's operating conditions are maintained regardless of whether the parameter P fluctuates up or down. If it is determined that the printer 1's operating conditions should be maintained (S5: YES), the CPU 21 executes printing for the R line for which the parameter P was acquired, while maintaining the printer 1's operating conditions (S39).

[0048] For example, the CPU 21 drives the printing unit 7 and power supply unit 8 under the "no limit" condition among the driving conditions of the printer 1 shown in FIG. 6. The printing speed of the printing unit 7 is set to a first printing speed V1, and the printing density is set to a first printing density D1. The first printing speed V1 is the fastest speed, and the first printing density D1 is the optimum density for printing. The first printing density D1 is set, for example, by the user. The optimum density is, for example, the median density between the lightest and darkest colors. Furthermore, the power supply unit 8 leaves the power supply limit in an off state. In other words, power can be supplied from the power supply unit 8 to the tablet PC 5.

[0049] 7, for example, printing by the printing unit 7 begins at time t0. The parameter P exhibits an upward trend during a section P1 from time t0 to t1.

[0050] The CPU 21 determines whether printing based on the image data is complete each time printing of an R line is completed (S41). If printing based on the image data is not complete (S41: NO), the CPU 21 returns the process to S3 and acquires the parameter P for the next R line.

[0051] On the other hand, if it is determined that the driving conditions of printer 1 should not be maintained (S5: NO), that is, if there is a possibility that printer 1 will need to be restricted or restricted in relation to each of the predetermined values ​​Th1 to Th6, the CPU 21 determines whether parameter P has increased (S7). If it is determined that parameter P has increased (S7: YES), the CPU 21 determines whether parameter P is equal to or greater than first predetermined value Th1 (S9). If it is determined that parameter P is less than first predetermined value Th1 (S9: NO), the CPU 21 exceptionally only needs to maintain the driving conditions of printer 1, and therefore executes printing for R lines without changing the driving conditions of printer 1 (S39).

[0052] If it is determined that the parameter P is equal to or greater than the first predetermined value Th1 (YES at S9), the CPU 21 determines whether the parameter P is equal to or greater than a second predetermined value Th2 (S11). If it is determined that the parameter P is smaller than the second predetermined value Th2 (NO at S11), i.e., if Th1≦P<Th2, the CPU 21 limits the power supply from the power supply unit 8 to the external device (S13).

[0053] For example, the CPU 21 drives the printing unit 7 and power supply unit 8 under the "first restriction" condition among the driving conditions of the printer 1 shown in Figure 6. The power supply unit 8 is restricted from supplying power to external devices. Restricting power supply means stopping power supply from the power supply unit 8 to external devices. In this case, no restrictions are imposed on the printing unit 7. In other words, the first printing speed V1 and the first printing density D1 are maintained.

[0054] The CPU 21 drives the printing unit 7 under the "first restricted" driving conditions with the power supply to the external device restricted, and executes printing of the R line (S39). The CPU 21 proceeds to S41.

[0055] 7, the parameter P drops temporarily during a section P11 from time t1 to time t2, but then rises, and at time t2, the parameter P becomes equal to or greater than the second predetermined value Th2.

[0056] If the CPU 21 determines that the parameter P is equal to or greater than the second predetermined value Th2 (S11: YES), it then determines whether the parameter P is equal to or greater than a third predetermined value Th3 (S15). If the CPU 21 determines that the parameter P is smaller than the third predetermined value Th3 (S15: NO), that is, Th2≦P<Th3, the CPU 21 limits the operating conditions of the printing unit 7 (S17). In this case, the CPU 21 limits the amount of power consumed by the printing unit 7 from the power supplied from the AC adapter 9.

[0057] For example, the CPU 21 drives the printing unit 7 under the "second limit" condition among the driving conditions of the printer 1 shown in Figure 6. For example, in cases A and B, the CPU 21 limits the power consumed by the printing unit 7 by slowing down the printing speed to a second printing speed V2 that is slower than the first printing speed V1. On the other hand, in cases C and D, the CPU 21 limits the power consumed by the printing unit 7 by executing the printing operation at a third printing density D3 that is lighter than the first printing density D1. Note that the third printing density D3 may be the same as or different from the second printing density D2 described below in cases A and B.

[0058] The CPU 21 drives the printing unit 7 under the "second restricted" driving conditions while restricting power supply to the external device, and executes printing of the R line (S39). The CPU 21 proceeds to S41.

[0059] 7, the parameter P drops temporarily during a period P12 from time t2 to time t3, but then rises until it reaches the third predetermined value Th3 at time t3.

[0060] If the parameter P is determined to be equal to or greater than the third predetermined value Th3 (S15: YES), the CPU 21 determines whether the parameter P is equal to or greater than the maximum rated value Th_max (S19). If the parameter P is determined to be smaller than the maximum rated value Th_max (S19: NO), and Th3≦P<Th_max holds, the CPU 21 further restricts the driving conditions of the printer 1 (S21).

[0061] For example, the CPU 21 drives the printing unit 7 under the "third limit" condition among the driving conditions of the printer 1 shown in FIG. 6 . For example, in case A, the CPU 21 limits the power consumed by the printing unit 7 by slowing down the printing speed to a third printing speed V3, which is slower than the second printing speed V2. In case B, the CPU 21 limits the power consumed by the printing unit 7 by executing a printing operation at a second printing density D2, which is lighter than the first printing density D1. In case C, the CPU 21 limits the power consumed by the printing unit 7 by slowing down the printing speed to a fourth printing speed V4, which is slower than the first printing speed V1 of the printing operation currently being executed by the printing unit 7. In this case, the fourth printing speed V4 may be the same as or different from the second printing speed V2 in case A. In case D, the CPU 21 limits the power consumed by the printing unit 7 by executing a printing operation at a fourth printing density D4, which is lighter than the third printing density D3.

[0062] The CPU 21 drives the printing unit 7 under the "third restricted" driving conditions while restricting power supply to the external device, and executes printing of the R line (S39). The CPU 21 proceeds to S41.

[0063] 7, the parameter P tends to decrease during a section P13 from time t3 to time t4, and reaches the fourth predetermined value Th4 at time t4.

[0064] On the other hand, if it is determined that the parameter P is equal to or greater than the maximum rated value Th_max (S19: YES), the CPU 21 further restricts the driving conditions of the printer 1 (S23), and returns the process to S1.

[0065] For example, the "fourth limit" driving condition is applied among the driving conditions of the printer 1 shown in Fig. 6. In this case, in any of cases A to D, printing cannot be continued and printing by the printing unit 7 is stopped. Note that in the example shown in Fig. 7, the parameter P does not reach the maximum rated value Th_max.

[0066] On the other hand, if it is determined that the acquired parameter P is not increasing, i.e., is decreasing (S7: NO), the CPU 21 determines whether the parameter P is greater than a fourth predetermined value Th4 (S25). If it is determined that the parameter P is greater than the fourth predetermined value Th4 (S25: YES), the CPU 21 exceptionally only needs to maintain the operating conditions of the printer 1, and therefore executes printing of the R line under the current operating conditions of the printing unit 7 (S39). The CPU 21 proceeds to S41.

[0067] If it is determined that the parameter P is equal to or less than the fourth predetermined value Th4 (S25: NO), the CPU 21 determines whether the parameter P is equal to or less than the fifth predetermined value Th5 (S29).If it is determined that the parameter P is greater than the fifth predetermined value Th5 (S29: YES), that is, if Th4≧P>Th5, the CPU 21 releases the restriction on the drive conditions (S31).

[0068] For example, the CPU 21 drives the printing unit 7 under the "second limit" condition among the driving conditions of the printer 1 shown in Figure 6. In case A, the CPU 21 accelerates from the third printing speed V3 to the second printing speed V2. In case B, the CPU 21 restores from the second printing density D2 to the first printing density D1. Meanwhile, in case C, the CPU 21 accelerates from the fourth printing speed V4 to the first printing speed V1. In case D, the CPU 21 restores from the fourth printing density D4 to the third printing density D3.

[0069] The CPU 21 drives the printing unit 7 under the "second restricted" driving conditions while restricting power supply to the external device, and executes printing of the R line (S39). The CPU 21 proceeds to S41.

[0070] 7, the parameter P tends to decrease during a section P14 from time t4 to time t5, with repeated increases and decreases. At time t5, the parameter P reaches a fifth predetermined value Th5.

[0071] On the other hand, if it is determined that the parameter P is equal to or less than the fifth predetermined value Th5 (S29: NO), the CPU 21 determines whether the parameter P is greater than a sixth predetermined value Th6 (S33). If it is determined that the parameter P is greater than the sixth predetermined value Th6 (S33: YES), i.e., if Th5≧P>Th6, the CPU 21 releases the restriction on the drive conditions (S35).

[0072] For example, the CPU 21 drives the printing unit 7 under the "first limit" condition among the driving conditions of the printer 1 shown in Figure 6. In cases A and B, the CPU 21 accelerates from the second printing speed V2 to the first printing speed V1. On the other hand, in cases C and D, the CPU 21 restores from the third printing density D3 to the first printing density D1.

[0073] The CPU 21 drives the printing unit 7 under the "first restricted" driving conditions with the power supply to the external device restricted, and executes printing for R lines (S39). The CPU 21 proceeds to S41.

[0074] 7, the parameter P rises once during a section P15 from time t5 to time t6, but then starts to decline, and at time t6, the parameter P reaches a sixth predetermined value Th6.

[0075] On the other hand, if it is determined that the parameter P is equal to or less than the sixth predetermined value Th6 (S33: NO), the CPU 21 cancels the restriction on power supply from the power supply unit 8 to the external device (S37). In this case, the CPU 21 does not immediately start power supply to the external device from the power supply unit 8. In other words, the CPU 21 maintains the "first restriction" in the printer 1 driving conditions and executes printing of R lines by the printing unit 7 (S39). The CPU 21 proceeds to S41.

[0076] 7, the parameter P rises once during a section P16 from time t6 to time t7, but then starts to decline. For example, printing by the printing unit 7 is completed at time t7.

[0077] If it is determined that printing based on the image data has been completed (S41: YES), the CPU 21 determines whether the setting for lifting the limit on power supply from the power supply unit 8 to the external device has been set (S43).If it is determined that the setting for lifting the limit on power supply from the power supply unit 8 to the external device has not been set (S43: NO), the CPU 21 returns the process to S1 and waits without lifting the limit on power supply.

[0078] On the other hand, if it is determined that the setting for lifting the restriction on power supply from power supply unit 8 to external devices has been made (S43: YES), i.e., if the processing of S37 has been performed, CPU 21 lifts the restriction on power supply from power supply unit 8 to external devices (S45). That is, after restricting power supply from power supply unit 8 to external devices, if parameter P becomes equal to or less than sixth predetermined value Th6 and the printing operation by printing unit 7 is completed, CPU 21 lifts the restriction on power supply from power supply unit 8 to external devices.

[0079] 7, for example, in section P3 from time t7 onwards, power supply unit 8 supplies power. That is, the restriction on power supply by power supply unit 8 that was imposed during section P2 from time t1 to t7 is lifted when printing is completed.

[0080] The CPU 21 returns the process to S1 and waits.

[0081] As described above, the CPU 21 acquires the parameter P, which indicates the magnitude of the load on the external power source when power is supplied from the external power source. If the acquired parameter P is equal to or greater than the first predetermined value Th1, the CPU 21 limits the power supply from the power supply unit 8 to the external device.

[0082] The printer 1 ensures sufficient power for the printer 1 to perform its printing operations by limiting the power supply to external devices according to the load on the external power source. This eliminates the need for the printer 1 to reduce the load required for the printer 1 to perform its printing operations. Therefore, when the printer 1 has the function of supplying power to external devices, it can maintain its printing operations even if the load on the external power source increases.

[0083] When the acquired parameter P is equal to or greater than the second predetermined value Th2, the CPU 21 limits the power consumed by the printing unit 7 from the power supplied from the external power source. When the load on the battery 11 becomes even greater, the printer 1 can maintain printing operations by limiting the power consumed by the printing unit 7.

[0084] The CPU 21 limits the power consumed by the printing unit 7 by slowing down the printing speed to a second printing speed V2 that is slower than the first printing speed V1 during the printing operation being performed by the printing unit 7. The printer 1 can maintain the printing operation while reducing the load on the external power supply through simple control.

[0085] When the parameter P is equal to or greater than the third predetermined value Th3, the CPU 21 limits the power consumed by the printing unit 7 by slowing down the printing speed to a third printing speed V3 that is slower than the second printing speed V2. When the parameter P is equal to or greater than the third predetermined value Th3, the CPU 21 limits the power consumed by the printing unit 7 by performing the printing operation at a second printing density D2 that is lighter than the first printing density D1 in the printing operation currently being performed by the printing unit 7. By slowing down the printing speed to the third printing speed V3 or lightening the printing density to the second printing density D2, the printer 1 can maintain the printing operation while further reducing the load on the external power supply.

[0086] After limiting the power consumed by the printing unit 7, if the parameter P becomes equal to or less than the fourth predetermined value Th4, the CPU 21 accelerates from the third printing speed V3 to the second printing speed V2. After limiting the power consumed by the printing unit 7, if the parameter P becomes equal to or less than the fourth predetermined value Th4, the CPU 21 restores the printing density from the second printing density D2 to the first printing density D1. When the load on the external power supply becomes lighter, the power that can be consumed by the printing unit 7 increases. In this case, the printer 1 executes the printing operation by accelerating to the second printing speed V2 before the limit, or by restoring to the first printing density D1. Therefore, the printer 1 can efficiently use the power of the external power supply.

[0087] After limiting the power consumed by the printing unit 7, if the parameter P becomes equal to or less than the fifth predetermined value Th5, the CPU 21 accelerates the printing speed from the second printing speed V2 to the first printing speed V1. If the load on the external power supply becomes lighter, the power that can be consumed by the printing unit 7 increases. In this case, the printer 1 accelerates to the first printing speed V1 before the limit and executes the printing operation. Therefore, the printer 1 can efficiently use the power of the external power supply.

[0088] The CPU 21 limits the power consumed by the printing unit 7 by executing the printing operation at a third print density D3 that is lighter than the first print density D1 in the printing operation currently being executed by the printing unit 7. The printer 1 can maintain the printing operation while reducing the load on the external power supply through simple control.

[0089] When the parameter P is equal to or greater than the third predetermined value Th3, the CPU 21 limits the power consumed by the printing unit 7 by executing the printing operation at a fourth print density D4 that is lighter than the third print density D3. When the parameter P is equal to or greater than the third predetermined value Th3, the CPU 21 limits the power consumed by the printing unit 7 by slowing down the printing speed to a fourth print speed V4 that is slower than the first print speed V1 of the printing operation being executed by the printing unit 7. By thinning the printing density to the fourth print density D4 or slowing down the printing speed to the fourth print speed V4, the printer 1 can maintain the printing operation while further reducing the load on the external power supply.

[0090] If the parameter P becomes equal to or less than the fourth predetermined value Th4 after limiting the power consumed by the printing unit 7, the CPU 21 restores the fourth print density D4 to the third print density D3. If the parameter P becomes equal to or less than the fourth predetermined value Th4 after limiting the power consumed by the printing unit 7, the CPU 21 accelerates the printing speed from the fourth print speed V4 to the first print speed V1. If the load on the external power supply becomes lighter, the power that can be consumed by the printing unit 7 increases. In this case, the printer 1 performs the printing operation by restoring the printing speed to the third print density D3 before the limit, or by accelerating to the first print speed V1. Therefore, the printer 1 can efficiently use the power of the external power supply.

[0091] After limiting the power consumed by the printing unit 7, if the parameter P becomes equal to or less than the fifth predetermined value Th5, the CPU 21 restores the print density from the third print density D3 to the first print density D1. If the load on the power supply becomes lighter, the power that can be consumed by the printing unit 7 increases. In this case, the printer 1 returns to the first print density D1 before the limit and executes the printing operation. Therefore, the printer 1 can efficiently use the power of the external power supply.

[0092] After limiting the power supply from the power supply unit 8 to the external device, if the parameter P becomes equal to or less than the sixth predetermined value Th6 and the printing operation by the printing unit 7 is completed, the CPU 21 releases the restriction on the power supply from the power supply unit 8 to the external device. If the load on the external power source becomes lighter, the power that can be consumed by the printer 1 increases. In this case, the printer 1 resumes the restriction on the power supply to the external device. This allows the printer 1 to efficiently use the power of the external power source. Furthermore, because the printer 1 maintains the restriction on the power supply to the external device until the printing operation is completed, it is possible to prevent the operating state of the printer 1 from changing mid-printing. This allows the printer 1 to maintain print quality.

[0093] The first predetermined value Th1 and the sixth predetermined value Th6 are different from each other. The third predetermined value Th3 and the fourth predetermined value Th4 are different from each other. The second predetermined value Th2 and the fifth predetermined value Th5 are different from each other. For example, if the predetermined values ​​Th1 to Th6 are the same, it is possible that the parameter P will fluctuate in a short period of time around each of the predetermined values ​​Th1 to Th6. In this case, for example, print speed restrictions and their lifting will occur frequently, making the printing operation of the printer 1 unstable. Therefore, the printer 1 can perform stable printing operations by setting each of the predetermined values ​​Th1 to Th6 to different values.

[0094] The external power source is an AC adapter 9. The printer 1 can maintain printing operations even when the load on the AC adapter 9 becomes large.

[0095] The CPU 21 estimates the parameter P based on image data printed on a medium by the printing unit 7. The CPU 21 acquires the estimated parameter P. Because the printer 1 estimates the parameter P, there is no need to provide a separate sensor, such as a temperature sensor, for detecting the load on the external power supply.

[0096] In the above description, the CPU 21 is an example of a "control unit" of the present invention. The AC adapter 9 is an example of a "power source" of the present invention. The tablet PC 5 is an example of an "external device" of the present invention. The processing of S3 executed by the CPU 21 is an example of an "acquisition processing" of the present invention. The processing of S13 executed by the CPU 21 is an example of a "first restriction processing" of the present invention. The processing of S17 executed by the CPU 21 is an example of a "second restriction processing" of the present invention. The processing of S21 executed by the CPU 21 is an example of a "third restriction processing" of the present invention. The processing of S21 executed by the CPU 21 is an example of a "fourth restriction processing" of the present invention. The processing of S31 is an example of a "first acceleration processing" of the present invention. The processing of S31 executed by the CPU 21 is an example of a "first concentration recovery processing" of the present invention. The processing of S31 executed by the CPU 21 is an example of a "second concentration recovery processing" of the present invention. The processing of S35 is an example of a "second acceleration processing" of the present invention. The processing of S31 executed by the CPU 21 is an example of a "third acceleration processing" of the present invention. The process of S35 executed by the CPU 21 is an example of the "third concentration restoration process" of the present invention. The process of S45 executed by the CPU 21 is an example of the "cancellation process" of the present invention. The process of S3 executed by the CPU 21 is an example of the "load estimation process" of the present invention.

[0097] The present invention is not limited to the above-described embodiments and modifications, and various other modifications are possible. The techniques disclosed in the above-described embodiments and modifications can be combined to the extent that they are not inconsistent. The printer 1 was a thermal printer, but this is not a limitation, and an inkjet printer may also be used. The external device was a tablet PC 5, but this is not a limitation. For example, the external device may be a smartphone, a PC, or other device. The AC adapter 9 was used as the external power source, but this is not a limitation. For example, a battery or the like may be substituted for the external power source. The printer 1 may receive power from an external device in accordance with the USB PD (USB Power Delivery) standard.

[0098] In the above embodiment, the first predetermined value Th1 to the sixth predetermined value Th6 are different values, but this is not limited to this. At least one of the first predetermined value Th1 to the sixth predetermined value Th6 may be the same value. For example, as shown in FIG. 8, the predetermined values ​​Th1 to Th3 may be the same value. In this case, the printer 1 restricts the printer 1 using, for example, only the first predetermined value Th1.

[0099] At time t0, printing is performed based on image data. A parameter P is sequentially estimated for the R line. During section P101 from time t0 to time t1, the parameter P increases. In this case, there are no restrictions on the operating conditions of the printer 1 ("no restrictions"). At time t1, the parameter P reaches a predetermined value Th1. In this case, the power supply unit 8's power supply to external devices is restricted ("first restriction"). Note that, during section P102 from time t1 onward, the power supply unit 8's power supply to external devices remains restricted. During section P111 from time t1 to t2, the parameter P temporarily decreases but then increases. At time t2, the parameter P again reaches the first predetermined value Th1. In this case, for example, the printing speed of the printing unit 7 is restricted from the first printing speed V1 to the second printing speed V2 ("second restriction"). During section P112 from time t2 to t3, the parameter P temporarily decreases but then increases. At time t3, the parameter P again reaches the predetermined value Th1. In section P113 after time t3, for example, the printing speed of the printing unit 7 is limited from the second printing speed V2 to the third printing speed V3 ("third limit").

[0100] In the example of FIG. 8, once a restriction is imposed, it is not released until printing is completed. However, the printer 1 may set predetermined values ​​Th4 to Th6 as in the above embodiment and release the restrictions sequentially. Note that the predetermined values ​​Th4 to Th6 may be the same or different. It is also possible that the parameter P does not decrease even when a restriction is imposed. In such a case, the restrictions may be applied sequentially, for example, after a predetermined time has passed. Also, a maximum rating Th_max may be set as in the above embodiment.

[0101] In the above embodiment, the first printing speed V1 is the fastest speed, but this is not limited thereto. For example, the first printing speed V1 may be set to any speed from the fastest speed to the slowest speed as appropriate. Furthermore, in the above embodiment, the first printing density D1 is the median density between the lightest and darkest colors, but this is not limited thereto. For example, the first printing density D1 may be set to any density from the lightest to the darkest colors as appropriate. Furthermore, the first printing speed V1 to the fourth printing speed V4 and the first printing densities D1 to D4 may be set on the printer 1 side or by the user.

[0102] In the above embodiment, power supply from the power supply unit 8 is stopped when the parameter P becomes equal to or greater than the first predetermined value Th1. However, this is not limiting. For example, the CPU 21 may limit the amount of power that can be supplied from the power supply unit 8 in a stepwise manner.

[0103] In the above embodiment, the parameter P is an integrated average value based on the average current value, but this is not limiting. For example, the parameter P may be a value based on the heat generation temperature of the AC adapter 9. For example, the AC adapter 9 is provided with a sensor that measures the temperature of the AC adapter 9. The CPU 21 acquires the measurement result of the temperature of the AC adapter 9 by the sensor as the parameter P. In this case, the predetermined values ​​Th1 to Th6 may be set appropriately based on the rated temperature of the AC adapter 9. Because the printer 1 directly detects the temperature of the AC adapter 9 with the sensor and uses the measurement result as the parameter P, it is possible to limit the load at a more accurate timing than when the load is estimated.

[0104] In the main process of the above embodiment, the printer 1 is driven by power from the AC adapter 9, but this is not limiting. In the main process, for example, the printer 1 may be driven by the battery 11. In this case, the predetermined values ​​Th1 to Th6 may be set appropriately based on the rated current of the battery 11. The printer 1 can maintain printing operations even when the load on the battery 11 increases.

[0105] When the printer 1 is powered by the battery 11, the parameter P may not be estimated, but may be determined, for example, by using the temperature of the battery 11 detected by the sensor 11A as the parameter P. In this case, the predetermined values ​​Th1 to Th6 may be set appropriately according to the rated temperature of the battery 11.

[0106] In the above embodiment, the parameter P is estimated when R=3, but this is not limited to this. The number of target lines R may be set as appropriate. Furthermore, in the above embodiment, after the parameter P for the three target lines is obtained, the parameter P for the next three target lines is calculated, but this is not limited to this. For example, after calculating the parameter P for lines 1 to 3, the parameter P may be calculated for lines 2 to 4. In other words, the lines that are the target of the calculation of the parameter P may or may not overlap.

[0107] In the above embodiment, the printer 1 performs printing by the printing unit 7 while estimating the parameter P, but this is not limited to this. For example, the parameter P may be estimated before printing. Printing by the printing unit 7 may be performed after the estimation is completed.

[0108] In the above embodiment, after the power supply restriction is released in the process of S37 and printing is completed, power can be supplied from the power supply unit 8 to the external device, but this is not limited to this. For example, power supply from the power supply unit 8 to the external device may be resumed when the release setting in S37 is performed.

[0109] Instead of the CPU 21, a USB PDIC 37, an ASIC, an FPGA (Field Programmable Gate Array), or the like may be used as a processor. The main processing may be distributed among multiple processors. The printer 1 may also include other non-transitory storage media, such as an HDD. The non-transitory storage media may be any storage media capable of retaining information regardless of the period for which the information is stored. The non-transitory storage media does not have to include a temporary storage medium (for example, a transmitted signal).

[0110] The various programs may be downloaded (i.e., transmitted as a transmission signal) from a server connected to a network (not shown) and stored in a memory such as an HDD. In this case, the various programs may be stored in a non-transitory storage medium such as an HDD provided in the server.

[0111] 1 Printer 5 Tablet PC 7 Printing unit 8 Power supply unit 9 AC adapter 11 Battery 21 CPU P Parameter V1 to V4 Print speed D1 to D4 Print density Th1 to Th6 Predetermined value

Claims

1. A printer driven by a power source, comprising: a printing unit capable of executing a printing operation on a medium based on the power of the power source; a power supply unit capable of supplying power to an external device based on the power of the power source; and a control unit, wherein the control unit executes an acquisition process to acquire a parameter indicating the magnitude of the load on the power source when power is supplied from the power source; and a first restriction process to restrict power supply from the power supply unit to the external device if the parameter acquired by the acquisition process becomes equal to or greater than a first predetermined value.

2. The printer according to claim 1, characterized in that the control unit executes a second limiting process to limit the power consumed by the printing unit from the power source when the parameter acquired by the acquisition process becomes equal to or greater than a second predetermined value that is equal to or greater than the first predetermined value.

3. The printer according to claim 2, characterized in that the second limiting process limits the power consumed by the printing unit by slowing down the printing operation being performed by the printing unit to a second printing speed that is slower than the first printing speed.

4. The printer described in claim 3, characterized in that the control unit executes at least one of: a third limitation process that limits the power consumed by the printing unit by slowing down to a third printing speed slower than the second printing speed when the parameter becomes equal to or greater than a third predetermined value that is equal to or greater than the second predetermined value; and a fourth limitation process that limits the power consumed by the printing unit by performing the printing operation at a second printing density that is lighter than the first printing density in the printing operation being performed by the printing unit when the parameter becomes equal to or greater than the third predetermined value.

5. The printer described in claim 4, characterized in that the control unit executes: a first acceleration process for accelerating from the third printing speed to the second printing speed if the parameter becomes equal to or less than a fourth predetermined value that is equal to or less than the third predetermined value after limiting the power consumed by the printing unit by the third limiting process; and a first density restoration process for restoring from the second printing density to the first printing density if the parameter becomes equal to or less than the fourth predetermined value after limiting the power consumed by the printing unit by the fourth limiting process.

6. The printer according to claim 5, wherein the third predetermined value and the fourth predetermined value are different from each other.

7. The printer according to claim 3, characterized in that the control unit executes a second acceleration process to accelerate from the second printing speed to the first printing speed if the parameter becomes equal to or less than a fifth predetermined value that is equal to or less than the second predetermined value after limiting the power consumed by the printing unit by the second limiting process.

8. The printer according to claim 7, wherein the second predetermined value and the fifth predetermined value are different from each other.

9. The printer according to claim 2, characterized in that the second limitation process limits the power consumed by the printing unit by executing the printing operation at a third print density that is lighter than the first print density in the printing operation being executed by the printing unit.

10. The printer described in claim 9, characterized in that the control unit executes at least one of: a third limitation process that limits the power consumed by the printing unit by performing the printing operation at a fourth print density that is lighter than the third print density when the parameter becomes equal to or greater than a third predetermined value that is equal to or greater than the second predetermined value; and a fourth limitation process that limits the power consumed by the printing unit by slowing down to a fourth print speed that is slower than the first print speed in the printing operation being performed by the printing unit when the parameter becomes equal to or greater than the third predetermined value.

11. The printer described in claim 10, characterized in that the control unit executes: a second density restoration process that restores the fourth print density to the third print density if the parameter becomes equal to or less than a fourth predetermined value that is equal to or less than the third predetermined value after limiting the power consumed by the printing unit by the third limiting process; and a third acceleration process that accelerates from the fourth printing speed to the first printing speed if the parameter becomes equal to or less than the fourth predetermined value after limiting the power consumed by the printing unit by the fourth limiting process.

12. The printer according to claim 11, wherein the third predetermined value and the fourth predetermined value are different from each other.

13. The printer according to claim 9, characterized in that the control unit executes a third density recovery process to recover from the third print density to the first print density when the parameter becomes equal to or less than a fifth predetermined value that is equal to or less than the second predetermined value after limiting the power consumed by the printing unit by the second limiting process.

14. The printer according to claim 13, wherein the second predetermined value and the fifth predetermined value are different from each other.

15. The printer according to claim 2, characterized in that the control unit executes a release process to release the restriction on power supply to the external device imposed by the first restriction process when, after the first restriction process has restricted the power supply from the power supply unit to the external device, the parameter becomes equal to or lower than a sixth predetermined value that is equal to or lower than the first predetermined value, and the printing operation by the printing unit has been completed.

16. The printer according to claim 15, wherein the first predetermined value and the sixth predetermined value are different from each other.

17. The printer according to claim 1, wherein the power source is an AC adapter.

18. The printer according to claim 1, wherein the power source is a battery.

19. The printer according to claim 1, characterized in that the control unit executes a load estimation process to estimate the parameters based on image data printed on the medium by the printing unit, and the acquisition process acquires the parameters estimated in the load estimation process.

20. The printer according to claim 1, characterized in that the power supply is provided with a sensor that measures the temperature of the power supply, and the acquisition process acquires the measurement result of the temperature of the power supply by the sensor as the parameter.

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