JP2023045997A - printer - Google Patents

Abstract

To solve the problem in which: a conventional printer includes a DC power supply that can change the voltage supplied to a thermal head by measuring the application voltage applied to the thermal head and controls the application voltage according to the current flowing in the thermal head, and thereby the device causes complication and cost increase.SOLUTION: A printer for performing printing by using a thermal head comprises a plurality of power supplies including a battery and a first power supply that supplies the power on the basis of the power from a commercial power supply. The printer, in such a state that the power is supplied from the first power supply, acquires a drop amount of the voltage supplied to the thermal head on the basis of the impedance of a circuit supplied with the power from the first power supply and the value of current flowing in the thermal head, and controls driving of the thermal head according to the acquired drop amount of the voltage.SELECTED DRAWING: Figure 3

Description

The present invention relates to printing devices.

In conventional thermal transfer printers, the voltage supplied to the thermal head is constant, so in order to change the recording density, it is necessary to control the recording data or control the energization time of the thermal head. . Patent document 1 discloses a thermal transfer printer that can change the recording density by controlling the voltage applied to the thermal head by measuring the applied voltage applied to the thermal head and having a DC power supply that can change the voltage supplied to the thermal head. is described.

JP-A-06-099605

However, since this prior art has a microcomputer for monitoring the power supply voltage and a power supply capable of changing the output voltage, the apparatus is complicated and the cost is increased.

SUMMARY OF THE INVENTION An object of the present invention is to solve at least one of the problems of the prior art described above.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a printing apparatus capable of optimizing printing by accurately detecting the voltage supplied to the head while suppressing complication of the apparatus and increase in cost.

In order to achieve the above object, a printing apparatus according to one aspect of the present invention has the following configuration. Namely
A printing device that performs printing using a thermal head,
a plurality of power sources including a battery and a first power source that supplies power based on power from a commercial power source;
A drop in the voltage supplied to the thermal head based on the impedance of the circuit to which the power is supplied from the first power supply and the value of the current flowing through the thermal head while the power is supplied from the first power supply. an acquisition means for acquiring
and control means for controlling driving of the thermal head according to the amount of voltage drop obtained by the obtaining means.

According to the present invention, it is possible to detect the voltage supplied to the head with high accuracy while suppressing the complication of the apparatus and the increase in cost, thereby optimizing printing.

Moreover, in the case of a configuration having two or more power sources, there is an effect that the difference in image due to the difference in the power sources does not occur.

Other features and advantages of the invention will become apparent from the following description with reference to the accompanying drawings. In the accompanying drawings, the same or similar structures are given the same reference numerals.

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
1 is an external view of a printer according to an embodiment of the invention; FIG. 2 is a block diagram showing the configuration of the control system of the printer according to the embodiment; FIG. 1A and 1B illustrate a configuration of a power supply control circuit according to an embodiment; FIG. FIG. 2 is a structural diagram of a thermal head used in the printer according to the embodiment; 4 is a flowchart for explaining processing for detecting impedance in a board of a power supply control circuit by a control unit of the printer according to the embodiment; 6 is a flowchart for explaining processing for detecting impedance outside the board of the power supply control circuit by the control unit of the printer according to the embodiment; 4 is a flowchart for explaining drive control of the thermal head by the printer according to the embodiment; FIG. 8 is a flowchart for explaining high voltage control in S705 of FIG. 7; FIG. FIG. 8 is a flowchart for explaining low voltage control in S706 of FIG. 7; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the invention according to the scope of claims. Although multiple features are described in the embodiments, not all of these multiple features are essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is an external view of a printer 1 according to an embodiment of the invention.

The printer 1 according to the embodiment is configured to be portable like a notebook computer. Power for the printer 1 is supplied from a battery and an AC adapter connected to a commercial power supply. The printer 1 selectively heats an input unit 13 having a keyboard and an input control unit, a display unit 14 having a display, a display control unit, etc., and a plurality of heating elements of a thermal head 6 arranged in rows in the main scanning direction. It has a printing unit 10 for printing on a recording medium (tube, sheet, etc.). The printer 1 further includes a cutting section 7 that is provided on the downstream side in the conveying direction of the recording medium and performs cutting processing on the recording medium, and a control section 200 (see FIG. 2) that controls these sections. Further, the printer 1 is formed with a transport path for transporting the recording medium.

The input unit 13 has function keys, letter/number/symbol keys, a space key, a conversion key, a cross direction key, a return key, and the like, almost like a notebook computer. By operating these keys, the operator can input the type and size of the recording medium including the tube M, printing conditions, cutting conditions, etc., and can set printing information, cutting information, and the like.

The display of the display unit 14 includes a display area for displaying various information such as the input mode, a character information display area for displaying characters, numbers, and symbols (hereinafter abbreviated as characters) input from the input unit 13, a character size, and the like. It has three display areas of a parameter display area that displays the . These various information display areas and parameter display areas are arranged above and below the character information display area.

In the above-mentioned various information display area, an input mode display for displaying (selecting) whether to input from the input unit 13 in alphanumeric characters, romaji, or hiragana, and input from the input unit 13 by inserting or overwriting An insert/overwrite mode display (edit mode display) is displayed. In addition, the display of "Type of print media" and "Cut setting" for how to separate pages when printing multiple pages in one print operation (whether or not to cut in half or not In the case of , the separator line is a solid line, a dotted line, or no separator line) is also displayed. In addition, "cut length" indicating the length of one tube (one label), "character layout" indicating whether the position of the character is centered or left aligned, and "margin" indicating from the left end of the tube M to the first character ” is also displayed. In addition, the previous page display, which is displayed when there is another page before the currently displayed page, and the next page display, which is displayed when there is another page after the currently displayed page, are displayed. . Furthermore, a tube feeder display indicating whether or not an optional unit (tube feeder) for assisting the transportation of the tube M is connected, a power display indicating that the power is turned on, and the like are displayed.

Also, in the parameter display area, there is a page display that shows the number of the currently displayed page, and the print orientation can be set to either "horizontal/horizontal writing", "vertical/vertical writing", or "vertical/horizontal writing". The print orientation is displayed to indicate whether or not to do so. Also, when adding a frame to a character, a frame frame display that displays the selected frame frame shape, a character size display that displays the selected character size, a line number display that displays the number of lines to be printed, and a selected character spacing The character spacing indication to be displayed. Furthermore, a continuous print display or the like is displayed to indicate how many pages the characters currently displayed are to be copied and printed.

On the other hand, in the character information display area, a character string of characters input from the input unit 13 (strictly speaking, characters displayed by converting the input character data in a predetermined manner) is displayed. In the character information display area, a cursor is displayed where the operator intends to input (see FIG. 1).

The printing unit 10 includes transport rollers 2a and 2b for transporting a recording medium, a platen roller 3 arranged downstream of the transport rollers 2a and 2b so as to face the thermal head 6, and a platen roller 3 downstream of the platen roller 3. It has a pinch roller 4 arranged opposite to the platen roller 3 . An ink ribbon R is interposed between the platen roller 3 and the thermal head 6 . The ink ribbon R is supplied from the ribbon supply reel of the ink ribbon cassette 8 and wound up on the ribbon take-up reel.

A stepping motor 5 that rotates the transport roller 2a, the platen roller 3, and the spool of the ribbon take-up reel of the ink cartridge 8 via gears (not shown) is arranged upstream of the transport rollers 2a and 2b. On one side of the ink cartridge 8 (left side in FIG. 1) and one side of the cutting section 7 (bottom side in FIG. 1), the thermal head 6 is retracted from the transport path via an arm (not shown). A stepping motor 9 is arranged to move the platen roller 3 between the retracted position and the printing position where the platen roller 3 is pressed against the platen roller 3 .

FIG. 1 shows a state in which a tube M is attached as a recording medium. In accordance with this example, during printing, the thermal head 6 is pressed against the tube M with the ink ribbon R of the ink cartridge 8 interposed therebetween. Then, according to the print data input from the input unit 13, the heating elements constituting the thermal head 6 are selectively energized to generate heat, thereby melting the ink of the ink ribbon R and printing one line of the character string on the tube M. print one by one. On the upstream side of the conveying rollers 2a and 2b and on the downstream side of the pinch roller 4, transmission integrated sensors are arranged for detecting the presence or absence of the recording medium and the leading edge of the conveyed recording medium.

FIG. 2 is a block diagram showing the configuration of the control system of the printer 1 according to the embodiment. In FIG. 2, parts common to those in FIG. 1 are indicated by the same reference numerals.

The control unit 200 has a CPU 210 that functions at high speed as a central processing unit, a ROM 211 that stores basic control programs and program data for the printer 1, a RAM 212 that functions as a work area for the CPU 210, and the like. These CPU 210, ROM 211, and RAM 212 are connected via an internal bus (not shown). Such a control unit 200 can be configured by, for example, a microcomputer circuit.

An external bus is connected to the control unit 200 . This external bus includes an input control unit (not shown) of the input unit 13, a display control unit (not shown) of the display unit 201, the thermal head 6 of the printing unit 10, a driver 202 for controlling the operation of the stepping motor, and a sensor. is connected to a sensor control unit 203 for controlling the information of The stepping motor described above is connected to the driver 202 , and various sensors (not shown) are connected to the sensor control unit 203 . The stepping motors 5 and 9 described above are driven and controlled via independent drivers, and the driver 203 collectively indicates these drivers.

The control unit 200 also has a buffer and an interface (not shown), and can be connected to, for example, a host device such as a personal computer via an external bus. Therefore, instead of inputting from the input unit 13, the operator can also input from the personal computer. Furthermore, by installing an external storage device such as a RAM card or USB, it is possible to use the data stored in these external storage devices. Further, a battery 205 and an AC adapter 204 are connected as power sources for driving the printer 1 . A power control circuit 213 controls the voltage supplied to the thermal head 6 of the printing unit 10 . The configuration of this power supply control circuit 213 will be described with reference to FIG. The non-volatile memory 214 non-volatilely stores the intra-substrate impedance and the like, which will be described later. The A/D converter 215 converts a supply voltage VH of the thermal head, which will be described later, into a digital signal. The CPU 210 can detect the voltage supplied to the thermal head 6 from the output of this A/D converter 215 . The control unit 200 also has an output port for outputting a SIG_C signal and the like, which will be described later, and a DATA signal and the like to the thermal head 6, but these are omitted in FIG.

FIG. 3 is a diagram illustrating the configuration of the power supply control circuit 213 according to the embodiment.

The power control circuit 213 is connected to the battery 205 and the AC adapter 204 as power supply sources. The power supply control circuit 213 includes a coil Ra for noise countermeasures and an FET (field effect detector) for turning on/off the voltage supply from the power supply A side (AC adapter 204 side) to VH (voltage supplied to the thermal head 6). transistors) Rb and Rc, diodes (not shown) for preventing backflow, and the like. In addition, although there are FETs, diodes, and the like in front of the booster circuit from the power source B side (battery 205 side) to VH, there are no parts behind the booster circuit 301, so a precise voltage can be ensured. Therefore, in order to measure the impedance on the power source A side (adapter side), the impedance can be detected with high accuracy by using the highly accurate boosted voltage (reference voltage A). Here, in order to supply the reference voltage A to the power supply A side, the reference voltage A is supplied from the output of the booster circuit 301 to the power supply A side via one stage of FET (field effect transistor) Tr1. Furthermore, by interposing a FET (Field Effect Transistor) Tr2 between the booster circuit 301 and VH, the connection between the booster circuit 301 and VH can be on/off controlled (connected/disconnected). Although it is possible to configure the circuit by adding more parts, it leads to deterioration in voltage accuracy, so it is desirable to configure the circuit with the minimum necessary parts.

In FIG. 3, when the SIG_C signal is turned on, the switching element (FET: field effect transistor) Tr1 is turned on and the output of the booster circuit 301 and the power source A are connected. On the other hand, when the SIG_C signal is turned on, the switching element Tr2 is turned off, and the connection between the output of the booster circuit 301 and VH is disconnected. Here, by measuring the supply voltage VH to the thermal head 6 at a portion as close as possible to the thermal head 6, the influence of the entire path to the thermal head 6 in the board of the power supply control circuit 213 can be detected and adjusted. can. The power control circuit 213 detects the voltage at the root of a supply port (such as a connector) for supplying power from the power control circuit 213 to the thermal head 6 in order to see the entire path to the thermal head 6 . Although a method of viewing from the base of the power supply port has been described this time, the same effect can be obtained without viewing from the base of the power supply port depending on the circuit configuration, so the configuration is not limited to this embodiment.

In FIG. 3, the SIG_A signal is turned on when it is detected that the AC adapter 204 is connected. Also, the SIG_B signal is turned off when it is detected that the AC adapter 204 is connected. As a result, when the AC adapter 204 is connected, the power from the AC adapter 204 is supplied from the power source A to VH, and the power supply from the battery 205 to the power source A is interrupted. Conversely, when the AC adapter 204 is not connected, the SIG_A signal is off and the SIG_B signal is on. As a result, power is supplied from the battery 205 to the power supply A and the thermal head 6 is driven by the power from the battery 205 .

FIG. 4 is a structural diagram of the thermal head 6 used in the printer 1 according to the embodiment.

The thermal head 6 has 128 resistors (heat generating elements) from R1 to R128. Here, the resistance value of each resistor is in the range of 800Ω±15%. A DATA signal (serial data) input in synchronization with the CLOCK signal is used to set whether or not to pass a current through these resistors. The shift register 401 takes in the DATA signal in synchronization with the rising edge of the CLOCK signal, and the 128-bit data input to the shift register 401 is latched in the latch circuit 402 by the LATCH signal. After that, when the STROBE signal is input to the driving circuit 403, the driving circuit 403 drives the heating element by causing current to flow through the resistor corresponding to the bit with the data of the DATA signal being "1". In other words, the thermal head 6 can freely set which resistor the current is to flow in, bit by bit.

FIG. 5 is a flowchart for explaining the process of detecting the impedance in the board of the power supply control circuit 213 by the control unit 200 of the printer 1 according to the embodiment. Note that the processing shown in this flowchart is achieved by the CPU 210 executing a program stored in the ROM 211 . Since this operation involves connecting the power sources, it cannot be performed by the user. This is a mode for adjustment performed by a service person when the adjustment at the time of shipment from the factory or when board replacement or the like occurs. First, the serviceman inserts the battery and then removes the adapter to start the operation.

First, in S501, the CPU 210 connects the output of the booster circuit 301 and the power source A portion by turning on the SIG_C signal in FIG. Next, in S502, the voltage V0 of VH at this time is measured (voltage measurement in static state). Next, in S503, a voltage is supplied from the power supply A side to flow a determined current value xA to VH. At this time, in order to flow the current xA, a discharge resistor (not shown) is used for disconnecting the power supply of the thermal head 6 used when detecting the resistance value of the thermal head 6 . However, the same thing can be done with a thermal head, a motor, or the like, since it is only necessary to supply a predetermined current. Next, the process advances to S504 to measure the voltage V1 when xA current is flowing (dynamic state measurement). Here, the voltage V1 is acquired based on the output of the A/D converter 215 for monitoring the voltage of VH. Then, the process advances to S505 to calculate the impedance R1 from the following equation (1).

R1=(V0-V1)/x... Formula (1)
where R1 is the in-substrate impedance, V0 is the static state voltage, V1 is the dynamic state voltage, and x is the specified current.

After calculating the impedance R1 in this manner, the process advances to S506 to save the impedance R1 in the nonvolatile memory 214, turn off the SIG_C signal, and end the process of detecting the impedance in the substrate.

As a result, the impedance in the circuit board that supplies voltage to the thermal head 6 is detected, and the impedance is held in a non-volatile manner so that it can be used for subsequent control.

FIG. 6 is a flowchart for explaining the process of detecting the impedance outside the board of the power supply control circuit 213 by the controller 200 of the printer 1 according to the embodiment. This processing is performed when printing with the voltage supplied from the AC adapter 204 . That is, the impedance R2 of the AC adapter 204 is measured while the AC adapter 204 is connected. Note that the processing shown in this flowchart is achieved by the CPU 210 executing a program stored in the ROM 211 .

When detection is started, first in S601, the CPU 210 measures the voltage V2 of VH (static voltage measurement). Next, proceeding to S602, the CPU 210 causes the determined current value x [A] to flow to VH in the same manner as in S503 described above. At this time, to flow the current x [A], a discharge resistor (not shown) is used to discharge the power supply of the thermal head used when detecting the resistance value of the thermal head. However, in the same way as described above, the thermal head, the motor, etc., can be implemented in the same way because it is only necessary to supply a predetermined current. Next, the process advances to S603 to measure the voltage V3 of VH when the current xA is flowing (dynamic state measurement). Then, in S604, the impedance R2 is calculated from the following equation (2).

R2={(V2-V3)/x}-R1... Formula (2)
where R1 is the aforementioned in-substrate impedance, V2 is the static state voltage, V3 is the dynamic state voltage, and x is the specified current.

After calculating the off-board impedance R2 in this way, the process proceeds to S605, the impedance R2 and the voltage V2 are stored in the nonvolatile memory 214, and this process ends.

As a result, the impedance R2 when the voltage is supplied from the AC adapter 204 is detected, and the impedance is held in a non-volatile manner so that it can be used for subsequent control.

FIG. 7 is a flowchart for explaining drive control of the thermal head 6 by the printer 1 according to the embodiment. Note that the processing shown in this flowchart is achieved by the CPU 210 executing a program stored in the ROM 211 .

This process measures the drop in the voltage supplied to the thermal head 6 when printing is performed using the AC adapter 204, and changes the driving of the thermal head 6 according to the amount of drop.

When this flow starts, first in S701, the CPU 210 acquires the number of resistors of the thermal head 6 that are simultaneously turned on based on the print data. Next, proceeding to S702, the CPU 210 calculates the current value Ia flowing through the thermal head 6 based on the number of resistors turned on at the same time. Next, in step S703, the CPU 210 calculates the voltage drop Vx when the output voltage V of the AC adapter 204 reaches VH, based on the impedance sum (R1+R2) and the current value Ia flowing through the thermal head 6. . Then, proceeding to S704, the CPU 210 compares the voltage VH that has decreased by the amount of the voltage drop Vx, that is, the voltage (V−Vx) that the voltage V of the power supply A has decreased with the reference voltage Vref. If it is higher than the reference voltage Vref, the process proceeds to S705, and high voltage control, which will be described later with reference to FIG. 8, is executed. On the other hand, if the lowered voltage VH is lower than the reference voltage Vref, the process advances to S706 to execute low voltage control, which will be described later with reference to FIG.

FIG. 8 is a flow chart for explaining the high voltage control in S705 of FIG.

First, in S801, the CPU 210 acquires the number of resistors of the thermal head 6 that are simultaneously turned on based on the print data, as in S701. Next, proceeding to S802, in the same manner as in S702, the current value Ia flowing through the thermal head 6 is obtained from the number of resistors. Next, in S803, similarly to S701, the voltage drop Vx when the output voltage V of the AC adapter 204 reaches VH is calculated from the impedance (R1+R2) and the current value Ia flowing through the thermal head 6. FIG. If the voltage drop Vx obtained in S701 to S703 is stored in the RAM 212, the voltage drop Vx can be read from the RAM 212 in S801, and steps S802 and S803 can be omitted.

Then, proceeding to S804, the CPU 210 calculates the voltage Vy by which the energy supplied to the thermal head 6 is greater than that in the case of the reference voltage Vref, according to the following equation (3).

Vy=V-Vx-Vref...Equation (3)
Here, V is the output voltage of the AC adapter 204, Vx is the voltage drop, and Vref is the reference voltage.

Next, proceeding to S805, the CPU 210 reduces the pulse width of the strobe signal (application time of the thermal head 6) by the voltage Vy corresponding to the increased energy, and drives the thermal head 6 to perform recording.

As described above, according to the printer according to the embodiment, it is possible to perform control when the voltage supplied to the head is higher than the reference voltage with a simple configuration and at a low cost without complicating the device configuration. . In addition, in the case of a configuration having two or more power supply systems, it is possible to prevent fluctuations in image density caused by differences in the voltages supplied to the heads.

Although the case where the voltage swings to the higher side than the specifications of the adapter has been described here, it is conceivable that the voltage swings to the lower side depending on the specifications of the adapter. The implementation method in that case is also described.

FIG. 9 is a flow chart explaining the low voltage control in S706 of FIG.

In S901-S903, similarly to S701-S703 and S801-S803 described above, the voltage drop Vx when the output voltage V of the AC adapter 204 reaches VH is calculated. Then, proceeding to S904, the CPU 210 calculates the voltage Vz corresponding to the decrease in the energy supplied to the thermal head 6 from the following equation (4).

Vz=Vref-V-Vx...Equation (4)
where V is the adapter output voltage, Vx is the voltage drop, and Vref is the reference voltage.

Then, proceeding to S905, the CPU 210 increases the pulse width of the strobe signal (application time of the thermal head) by the voltage Vz corresponding to the lower energy, and performs printing.

In this way, according to the printer according to the embodiment, it is possible to perform control when the voltage supplied to the head is lower than the reference voltage with a simple configuration and at a low cost, without complicating the device configuration. In addition, in the case of a configuration having two or more power supply systems, it is possible to prevent fluctuations in image density caused by differences in the voltages supplied to the head.

In the above embodiment, the method of using the boosted power supply is described, but the same effect can be obtained by other methods such as preparing a reference power supply. It goes without saying that there is no limit.

(Other embodiments)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in the computer of the system or apparatus reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, to publicize the scope of the invention, the following claims are included.

Reference Signs List 1 Printer 200 Control unit 204 AC adapter 205 Battery 210 CPU 211 ROM 212 RAM 213 Power control circuit 214 Non-volatile memory 215 A/D converter

Claims (11)

A printing device that performs printing using a thermal head,
a plurality of power sources including a battery and a first power source that supplies power based on power from a commercial power source;
A drop in the voltage supplied to the thermal head based on the impedance of the circuit to which the power is supplied from the first power supply and the value of the current flowing through the thermal head while the power is supplied from the first power supply. an acquisition means for acquiring
a control means for controlling driving of the thermal head according to the amount of voltage drop obtained by the obtaining means;
A printing device comprising: 2. A printing apparatus according to claim 1, wherein the current value flowing through said thermal head is obtained based on the number of resistors of said thermal head driven simultaneously. A first impedance for acquiring and holding a first impedance in a substrate to which power is supplied from the first power supply detected based on the voltage supplied from the battery in a state where power is not supplied from the first power supply 3. A printing device according to claim 1, further comprising holding means. A first voltage when no current is applied to the thermal head and a second voltage when a current is applied to the thermal head are held in the first holding means while power is being supplied from the first power supply. 4. A second holding means for acquiring and holding a second impedance outside the board to which power is supplied from the first power supply, based on the first impedance that is supplied from the first power supply. The printing device according to . The obtaining means obtains an impedance obtained by adding the first impedance held by the first holding means and the second impedance held by the second holding means, and a current value flowing through the thermal head. 5. The printing apparatus according to claim 4, wherein the amount of voltage drop is acquired based on the product of . When the voltage supplied to the thermal head after the amount of voltage drop is higher than a reference voltage, the control means performs control so that the energy for driving the thermal head is reduced. The printing device according to claim 1. 7. The printing apparatus according to claim 6, wherein control is performed such that energy for driving the thermal head is reduced by shortening a pulse width of a strobe signal for driving the thermal head. When the voltage supplied to the thermal head after the amount of voltage drop is lower than a reference voltage, the control means performs control so that the energy for driving the thermal head increases. The printing device according to claim 1. 9. The printing apparatus according to claim 8, wherein the pulse width of a strobe signal for driving the thermal head is lengthened to increase energy for driving the thermal head. 10. The printing apparatus according to any one of claims 1 to 9, further comprising a booster circuit for boosting the voltage from the battery, wherein power from the battery is supplied from the booster circuit. It further comprises a switching element that is turned on when the first impedance is obtained, and outputs an output of a booster circuit that boosts voltage from the battery to a substrate to which power is supplied from the first power supply. 4. The printing device according to claim 3.

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