Printing apparatus and method for controlling the printing apparatus

Abstract

There was a risk that the size of the device would increase. [Solution] The printing apparatus comprises a head for ejecting liquid onto a medium, a platen for supporting the medium, a heating unit for heating the platen, a head temperature detection unit for detecting the temperature of the head, a carriage for supporting the head and capable of moving in the scanning direction via the top of the platen, and a control unit for controlling the heating unit and the carriage. The control unit is characterized in that, when the temperature detected by the head temperature detection unit is below a predetermined temperature, it moves the head above the platen using the carriage and warms the head with the platen heated by the heating unit.

Description

Technical Field

[0001] The present invention relates to a printing apparatus and a method for controlling the printing apparatus.

Background Art

[0002] Conventionally, as shown in Patent Document 1, an apparatus is known that includes a head having nozzles for discharging a liquid, a heating unit for heating a medium onto which the liquid has been discharged, and a blowing unit that is disposed at an end in the moving direction of the head and blows air onto the nozzle surface of the head.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described apparatus, it is necessary to dispose the blowing unit at an end in the moving direction of the head, which may increase the size of the apparatus.

Means for Solving the Problems

[0005] The printing apparatus includes a head that discharges a liquid onto a medium, a platen that supports the medium, a heating unit that heats the platen, a head temperature detection unit that detects the temperature of the head, a carriage that supports the head and is movable in a scanning direction via above the platen, and a control unit that controls the heating unit and the carriage. When the temperature detected by the head temperature detection unit is equal to or lower than a predetermined temperature, the control unit moves the head above the platen by the carriage and warms the head by the platen heated by the heating unit.

[0006] A control method for a printing apparatus comprising a head for dispensing liquid onto a medium, a platen for supporting the medium, a heating unit for heating the platen, a head temperature detection unit for detecting the temperature of the head, and a carriage for supporting the head and movable in the scanning direction via the top of the platen, characterized in that when the temperature detected by the head temperature detection unit is below a predetermined temperature, the carriage moves the head above the platen and heats the head with the platen heated by the heating unit. [Brief explanation of the drawing]

[0007] [Figure 1] A perspective view showing a printing device. [Figure 2] A block diagram showing the configuration of a printing device. [Figure 3] A cross-sectional view showing the main parts of a printing device. [Figure 4] A flowchart showing the main routine for heating the print head. [Figure 5] A flowchart showing a subroutine for heating the heater. [Figure 6] A flowchart showing a subroutine for maintaining the print head. [Figure 7] A graph showing the relationship between the platen's set temperature and the head's target temperature. [Modes for carrying out the invention]

[0008] 1. Configuration of the printing device An embodiment of the printing apparatus 1 will be described below with reference to the drawings. Directions in the drawings will be described using a three-dimensional coordinate system. For the sake of explanation, the positive direction of the Z axis will be referred to as the upward direction or simply up, and the negative direction as the downward direction or simply down; the positive direction of the X axis will be referred to as the right direction or simply right, and the negative direction as the left direction or simply left; and the positive direction of the Y axis will be referred to as the forward direction or simply forward, and the negative direction as the backward direction or simply backward.

[0009] As shown in Figure 1, the printing apparatus 1 houses the printing unit 10, maintenance unit 20, circuit board 51, etc., inside the outer casing 40, which is a case. The outer casing 40 is supported by left and right legs 43. The exterior 40 is fitted with a cover 42 that covers the central part of the printing device 1, allowing the printing unit 10 to be seen while printing. The maintenance unit 20 is located to the right of the printing device 1. The exterior 40 is also fitted with an opening / closing cover 41 that can be opened and closed above and to the right of the maintenance unit 20. The medium P is transported along the transport direction F from rear to front. The medium P may be, for example, paper or a resin such as film.

[0010] The printing device 1 includes an input / output unit 50. The input / output unit 50 is a user interface for the user. The input / output unit 50 is, for example, a touch panel display. The input / output unit 50 includes a display panel, which is an output unit that displays various information, and a detection panel, which is an input unit. In the input / output unit 50, the input unit may be a keyboard, mouse, buttons, etc., and the output unit may be a stand-type liquid crystal display, etc. Under the control of the control unit 60 (described later), the input / output unit 50 detects user input via the input unit and displays predetermined information via the output unit.

[0011] As shown in Figure 2, the circuit board 51 is equipped with a control unit 60, a storage unit 61, and a communication unit 52. The control unit 60 includes a CPU (Central Processing Unit). The CPU is also called a processor. The control unit 60 can comprehensively control each part of the printing apparatus 1. The memory unit 61 is composed of various types of memory, including rewritable non-volatile memory such as flash ROM (Read Only Memory) and HDD (Hard Disk Drive), and volatile memory such as RAM (Random Access Memory).

[0012] The control unit 60 reads programs such as firmware stored in the non-volatile memory of the storage unit 61 and executes them using the volatile memory of the storage unit 61 as a working area. The non-volatile memory of the storage unit 61 also stores values ​​and calculation formulas that the control unit 60 uses when controlling each part. The communication unit 52 is configured to include a circuit capable of communication wirelessly or via a wired connection. The communication unit 52 has an antenna in the case of wireless communication and a connector in the case of wired communication. The communication unit 52 can communicate with an external device (not shown).

[0013] The various parts of the printing apparatus 1 will be described in detail with reference to Figures 2 and 3. As shown in Figure 3, the printing unit 10 consists of a head 12 including nozzles 13 and nozzle plate 14, and a first sensor 15. The printing unit 10 is mounted on a carriage 11. The scanning unit 17 includes a carriage motor (not shown). Under the control of the control unit 60, the carriage 11 moves along the carriage axis 16 in left and right scanning directions, including a first scanning direction S1 and a second scanning direction S2, by the carriage motor of the scanning unit 17.

[0014] As the carriage 11 moves, the printing unit 10 supported by the carriage 11, as well as the head 12 including the nozzles 13 and nozzle plate 14, and the first sensor 15 included in the printing unit 10, also move in the scanning direction. To simplify the explanation, the movement of these components by the carriage 11 under the control of the control unit 60 will be omitted in the following explanation. Furthermore, it will be assumed that one of these components moves in the scanning direction as a result of the movement of the carriage 11. A printhead 12 that prints while moving in this manner is called a serial head.

[0015] As shown in Figure 3, the print head 12 of the print unit 10 can move together with the carriage 11 between the heating area HA and the maintenance area MA, which are also the printing area. The heating area HA is the area where the head 12 is located above the platen 30, and is the area where the head 12 faces the medium P or the platen 30. As will be described later, the head 12 can be heated in the heating area HA. In the following, heating the head 12 by the platen 30 in the heating area HA is also referred to as warming the head 12. The boundary between the left heating area HA and the right maintenance area MA is the platen end 30a which is the right end of the platen 30. In this way, the carriage 11 supports the head 12 and is movable in the scanning direction via above the platen 30.

[0016] The head 12 has a plurality of nozzles 13 formed on the nozzle plate 14. The nozzle plate 14 is also a nozzle surface where the nozzles 13 are open. The nozzles 13 open downward. When printing, the head 12 moves in the second scanning direction S2 which is the direction from the maintenance area MA to the heating area HA, and reaches a position facing the medium P supported by the platen 30. The head 12 is an inkjet head that discharges ink which is a liquid. Under the control of the control unit 60, the head 12 discharges a plurality of colors of ink such as CMYKW (Cyan, Magenta, Yellow, Black, White) downward from the nozzles 13 and attaches them to the medium P. The ink attached to the medium P forms dots and can perform predetermined printing. The ink may contain a solvent.

[0017] The first sensor 15 is a head temperature detection unit that detects the temperature of the head 12. The control unit 60 can obtain the first detection temperature DH which is the temperature of the head 12 and is the head detection temperature, by the first sensor 15. The first sensor 15 may be, for example, a temperature detection element such as a thermistor, or may be composed of a circuit including an OP amplifier that detects the change in the resistance value of wiring such as the internal circuit of the head 12. As described later, under the control of the control unit 60, the head 12 can be heated in the heating region HA to reach the target temperature TH while the first detection temperature DH is obtained by the first sensor 15.

[0018] The head 12 can be composed of multiple head chips (not shown). In this case, a first sensor 15 can be provided for each head chip. The control unit 60 can also obtain the temperature from each of these first sensors 15, calculate the average value, and use this as the first detected temperature DH. Alternatively, the first sensor 15 can be provided on any of the multiple head chips, and the control unit 60 can calculate the average value of these sensors and use it as the first detected temperature DH.

[0019] The medium P is supported by the platen 30 and, under the control of the control unit 60, is transported forward in the transport direction F by the transport unit 18. The transport unit 18 includes a transport motor (not shown). The platen 30 is positioned to face the nozzle 13 and the nozzle plate 14. The platen 30 contains a heater 31, which is a heating element, and a second sensor 32 inside.

[0020] The heater 31 is composed of a component that generates Joule heat, such as a heat-generating resistance wire. The heater 31 is switched on and off by the control unit 60. The heater 31 is supported by the platen 30 and can dry the ink of the printed medium P. The second sensor 32 may be, for example, a temperature sensing element such as a thermistor, or it may be configured as a circuit including an operational amplifier that detects changes in the resistance value of the heater 31. As described later, under the control of the control unit 60, the heater 31 can heat the platen 30 to the set temperature TP while acquiring the second detected temperature DP, which is the platen detection temperature and is detected by the second sensor 32. The set temperature TP is also the target temperature when heating the platen 30.

[0021] The platen 30 has multiple holes (not shown) that penetrate vertically. Under the control of the control unit 60, the fan 33 can generate an airflow from top to bottom. This airflow can pass through the multiple holes in the platen 30. The medium P can be adsorbed onto the platen 30 by the airflow attempting to pass through the multiple holes. By adsorbing the medium P onto the platen 30, the distance from the nozzle 13 becomes constant, and the size of the formed dots can also be kept constant. In this way, the fan 33 adsorbs the medium P onto the platen 30, improving print quality. Furthermore, if there is no medium P on the platen 30, the fan 33 does not need to generate airflow.

[0022] As shown in Figure 3, the maintenance unit 20, which is the maintenance section, comprises a flushing unit 21, a suction unit 22, and a capping unit 23 in the maintenance area MA, in order toward the first scanning direction S1, starting from the right side of the platen end 30a. These are attached to frame 45. Furthermore, the carriage shaft 16 and platen 30 mentioned above are also attached to frame 45. During maintenance, the head 12 moves in the first scanning direction S1, which is the direction from the heating region HA to the maintenance region MA, and takes a position facing the maintenance unit 20. Specifically, under the control of the control unit 60, the head 12 can undergo various types of maintenance, such as those described below, in a position where it can face each of the units that make up the maintenance unit 20.

[0023] In the maintenance unit 20, the flushing unit 21 is positioned closest to the platen 30 and to the right of the platen end 30a. The flushing unit 21 can receive ink, which is liquid ejected from the nozzle 13 of the head 12, as part of maintenance. The flushing unit 21 has an absorbent (not shown) that receives the ink ejected from the nozzle 13 by flushing. Flushing is the process of forcibly expelling foreign matter, air bubbles, deteriorated ink, or thickened ink that may be causing ejection problems by ejecting ink from nozzle 13. Flushing is also referred to as a "discarding" of liquid ink.

[0024] In the maintenance unit 20, the suction unit 22 is located to the right of the flushing unit 21. The suction unit 22 has a suction cap and a suction pump (neither of which are shown) for drawing liquid ink from the head 12. As part of maintenance, the suction unit 22 can perform suction cleaning by capping the nozzle 13 and nozzle plate 14 of the head 12 with a suction cap and using a suction pump to suck up the ink from inside the nozzle 13 of the head 12. Suction cleaning is an operation that sucks up air bubbles, foreign matter, etc., from inside the nozzle 13 that cause ejection problems along with the ink, and also sucks up deteriorated ink, thickened ink, etc.

[0025] In the maintenance unit 20, the capping unit 23 is located to the right of the suction unit 22. The capping unit 23 has a cap (not shown). For maintenance, the capping unit 23 can cap the nozzle 13 and nozzle plate 14 of the head 12 with a cap from below. As a result, the capping unit 23 can seal the nozzle 13 and nozzle plate 14, suppressing the thickening of the ink in the nozzle 13 and preventing clogging of the nozzle 13.

[0026] The suction unit 22 and the capping unit 23 have a lifting mechanism (not shown) that raises and lowers the caps of the nozzle 13 and nozzle plate 14 of the head 12, respectively. The printing device 1 performs maintenance on the print head 12 using the maintenance unit 20, for example, when printing is paused, when not in use, when the power is off, or when the heating of the print head 12 (described later) is stopped.

[0027] Furthermore, when the head 12 moves from the heating region HA to the maintenance unit 20 in the maintenance region MA, the closer the unit is to the platen 30, the shorter the distance it travels and the less time it takes. In the example shown in Figure 3, the flushing unit 21, which is closest to the platen 30, requires the least travel time and distance for the head 12, followed by the suction unit 22. In maintenance, if flushing is frequent, followed by suction cleaning, this arrangement reduces the total travel time and distance, improving throughput.

[0028] Incidentally, as described above, the heater 31 heats the platen 30, which in turn heats the medium P supported by the platen 30, thereby drying the ink adhering to the medium P. At this time, vapor may be generated from the ink adhering to the medium P and rise towards the head 12 above. When the nozzle plate 14 of the head 12 is not heated, its temperature is lower than that of the platen 30. Due to the temperature difference between the platen 30 and the nozzle plate 14, rising steam may adhere to the nozzle plate 14 and condense. If condensation occurs on the nozzle plate 14, the condensed liquid may adhere to the area around the nozzle 13, potentially causing poor discharge.

[0029] Therefore, the printing apparatus 1 heats the head 12 to suppress condensation on the nozzle plate 14, as described below. Furthermore, if the heater 31 is stopped and the platen 30 is not heated, the temperature difference between the platen 30 and the nozzle plate 14 is small, thus suppressing condensation on the nozzle plate 14. Therefore, in this case, the head 12 does not need to be heated.

[0030] 2. Control method for the printing device The control method for the printing device 1 will be explained with reference to Figures 4 to 7. As shown in the main routine of Figure 4, the control unit 60 starts processing and first performs the processing of Sub-A(S200), which is a subroutine that heats the heater 31 of the platen 30 shown in Figure 5. The control unit 60 may start processing based on the user's input of an instruction to heat the head 12 to the input / output unit 50 of the printing device 1, or on the communication unit 52's instruction to heat the head 12 to an external device or acquisition of print data.

[0031] As shown in Figure 5, during the processing of the Sub-A subroutine, the control unit 60 turns on the power supply to the heater 31 of the platen 30 and heats it (S201). Note that predetermined printing may have already been performed before the control unit 60 starts processing. The platen 30 is heated by the powered heater 31, and the ink of the printed medium P can be dried. The control unit 60 obtains the second detected temperature DP, which is the temperature detected by the second sensor 32, and determines whether it is higher than the set temperature TP of the platen 30 (S202).

[0032] Furthermore, the control unit 60 may first determine whether the second detected temperature DP is higher than the set temperature TP when processing the subroutine of Sub-A. The control unit 60 can start heating by energizing the heater 31 if it determines that the second detected temperature DP is below the set temperature TP (S201). On the other hand, if the control unit 60 determines that the second detected temperature DP is higher than the set temperature TP, it may not energize the heater 31 and return to the main routine shown in Figure 4. The control unit 60 can avoid overheating the platen 30.

[0033] The set temperature TP is stored in the storage unit 61. The set temperature TP may also be stored in the storage unit 61 based on input from the user to the input / output unit 50 of the printing device 1, or on instructions from an external device obtained by the communication unit 52. The control unit 60 can read the set temperature TP from the storage unit 61 and process it. The set temperature TP is preferably set to a higher value according to the amount of ink ejected onto the medium P in order to dry the ink adhering to the medium P. For example, the set temperature TP is set to a higher value as the print duty cycle increases. Furthermore, it is preferable that the set temperature TP be a value that corresponds to the type and basis weight of the medium P. For example, as the basis weight of the medium P increases, the set temperature TP is set to a higher value.

[0034] If the control unit 60 determines that the second detected temperature DP is not higher than the set temperature TP (S202:NO), it continues to energize the heater 31 and continue heating (S201). Meanwhile, when the platen 30 becomes warm and the control unit 60 determines that the second detected temperature DP has risen above the set temperature TP (S202: YES), it turns off the power supply to the heater 31 to stop heating (S203) and returns to the main routine shown in Figure 4. When the platen 30 is heated by the heater 31 to dry the ink in the medium P, the medium P may become distorted. For this reason, it is preferable to use the fan 33 to adsorb the medium P onto the platen 30.

[0035] Although not shown in the figure, it is preferable that the control unit 60 also processes the Sub-A (S200) subroutine sequentially in parallel with the processing of the main routine in Figure 4, so that the temperature of the platen 30 maintains the set temperature TP. In this way, the control unit 60 can acquire the second detected temperature DP using the second sensor 32 and heat the platen 30 with the heater 31 so that the platen 30 reaches the set temperature TP.

[0036] Before starting printing, the user can input a heating command for the head 12 via the input / output unit 50 of the printing device 1, thereby preheating the platen 30. When the control unit 60 receives print data, it can start printing without heating the platen 30. Alternatively, when the control unit 60 receives print data, it can start printing by heating the platen 30 for a shorter time than usual. The control unit 60 can improve the printing throughput, including the heating time of the platen 30.

[0037] Before the control unit 60 starts processing, the head 12 is assumed to be in the position of the capping unit 23 in the maintenance area MA and is capped. As shown in Figure 4, the control unit 60 moves the head 12 from the position of the capping unit 23 in the maintenance area MA to the heating area HA (S101). At this time, it is preferable to move the entire nozzle plate 14 of the head 12 to a position in the heating region HA that extends beyond the platen end 30a. Furthermore, it is preferable to move the entire nozzle plate 14 of the head 12 to a position in the heating region HA that extends beyond a predetermined distance or more from the platen end 30a. As will be described later, the entire nozzle plate 14 can be effectively heated by the heated platen 30.

[0038] The head 12 is positioned above the platen 30, which is heated to a set temperature TP. The head 12 can be heated by radiant heat from the platen 30 via the medium P. That is, the head 12 can be heated while it is located in the heating region HA. At this time, the nozzle plate 14 of the head 12 is also heated, reducing the temperature difference with the platen 30. As a result, condensation of steam rising from the medium P onto the nozzle plate 14 is suppressed, and nozzle 13 discharge failure is suppressed.

[0039] In this way, the printing apparatus 1 can heat the head 12 and suppress condensation by moving the head 12 above the platen 30 heated by the heater 31. That is, the head 12 can be heated using the platen 30 which has a heater 31 for drying the ink adhering to the medium P, thereby suppressing condensation on the head 12. The printing apparatus 1 eliminates the need for new components to suppress condensation on the print head 12, thereby preventing an increase in size.

[0040] Next, the control unit 60 performs the processing of Sub-B(S300), which is a subroutine for maintaining the head 12 shown in Figure 6. As shown in Figure 6, in the processing of the Sub-B subroutine, the control unit 60 determines whether a predetermined time, or a predetermined timing, has elapsed (S301). When the control unit 60 determines that the predetermined timing has elapsed (S301: YES), it moves the head 12 from the heating area HA to the maintenance area MA (S302), and the maintenance unit 20 performs maintenance on the head 12 (S303).

[0041] The predetermined timing is the interval at which the control unit 60 performs maintenance on the head 12 using the maintenance unit 20. After maintenance, the control unit 60 moves the head 12 from the maintenance area MA to the heating area HA (S304). The control unit 60 enables heating of the head 12 by the platen 30 and returns processing to the main routine shown in Figure 4. Furthermore, if the control unit 60 determines that a predetermined timing has not elapsed (S301:NO), it returns processing to the main routine shown in Figure 4.

[0042] When the print head 12 is heated by the platen 30, the ink in the nozzle 13 gradually thickens, which may cause the nozzle 13 to clog. For this reason, the predetermined timing is set to a time before the ink in the nozzle 13 thickens and clogs. As part of the maintenance of the head 12, the control unit 60 may, for example, move the head 12 to the position of the flushing unit 21 in the maintenance area MA and perform flushing with the flushing unit 21. As part of the maintenance of the head 12, the control unit 60 may also move the head 12 to the position of the suction unit 22 and perform suction cleaning.

[0043] Furthermore, as the first detected temperature DH increases, the ink in the nozzle 13 becomes thicker, which may cause the nozzle 13 to clog. Therefore, to prevent the ink in the nozzle 13 from thickening and clogging, the predetermined timing is set to become shorter as the first detected temperature DH increases. In other words, the control unit 60 can increase the frequency of maintenance of the head 12 as the first detected temperature DH increases.

[0044] The predetermined timing set as described above is stored in the storage unit 61 as an interval corresponding to the first detected temperature DH. The control unit 60 reads the predetermined timing corresponding to the first detected temperature DH from the storage unit 61 and performs maintenance. Thus, when the time spent warming the head 12 has elapsed, the control unit 60 moves the head 12 to the maintenance unit 20 using the carriage 11 and performs maintenance on the head 12. The control unit 60 can perform maintenance on the head 12 as needed while heating it.

[0045] Next, as shown in Figure 4, the control unit 60 determines whether the first detected temperature DH of the head 12, acquired by the first sensor 15, is higher than the target temperature TH (S102). The target temperature TH is stored in the storage unit 61. The target temperature TH may also be stored in the storage unit 61 based on input from the user to the input / output unit 50 of the printing device 1, or based on instructions from an external device obtained by the communication unit 52. The control unit 60 can read the target temperature TH from the storage unit 61 and process it.

[0046] If the control unit 60 determines that the first detected temperature DH is not higher than the target temperature TH (S102:NO), it continues to heat the head 12 in the heating region HA without changing the position of the head 12. The control unit 60 also continues to process the subroutine of Sub-B (S300). The control unit 60 can perform maintenance at predetermined timings while heating the head 12.

[0047] Thus, if the first detected temperature DH, which is the temperature detected by the first sensor 15, which is the head temperature detection unit, is less than or equal to the target temperature TH, the control unit 60 can move the head 12 to the heating region HA, which is above the platen 30, using the carriage 11. The control unit 60 can then heat the head 12 with the platen 30 heated by the heater 31, which is the heating unit.

[0048] The control unit 60 may determine whether the first detected temperature DH is higher than the target temperature TH after processing the subroutine of Sub-A (S200) and before moving the head 12 from the maintenance area MA to the heating area HA (S101). The control unit 60 can move the head 12 to the heating region HA and heat it if it determines that the first detected temperature DH is below the target temperature TH. On the other hand, if the control unit 60 determines that the first detected temperature DH is higher than the target temperature TH, it may keep the head 12 in the maintenance region MA. The control unit 60 can avoid overheating the head 12.

[0049] The control unit 60 can calculate the time required to heat the head 12 in the heating region HA based on the temperature difference between the first detected temperature DH and the target temperature TH. This time is the time required for the first detected temperature DH to become higher than the target temperature TH. The formula for calculating this time is stored in the memory unit 61. The control unit 60 can read this formula from the memory unit 61 and display the calculated time using the input / output unit 50 to inform the user.

[0050] If the first detected temperature DH does not rise above the target temperature TH even after exceeding the time required to heat the head 12, the control unit 60 can determine that an error has occurred. The control unit 60 may also determine that an error has occurred when the time required to heat the head 12 exceeds a predetermined range. When the control unit 60 determines that an error has occurred, it turns off the power to the heater 31 to stop heating and can notify the user that an error has occurred by displaying a message via the input / output unit 50. Then, the control unit 60 terminates processing.

[0051] On the other hand, when the head 12 becomes warm and the control unit 60 determines that the first detected temperature DH has risen above the target temperature TH (S102: YES), it moves the head 12 from the heating region HA to the maintenance region MA (S103), separates it from the platen 30, and stops heating the head 12. The control unit 60 can prevent the head 12 from becoming excessively hot above the target temperature TH. At this time, for example, the control unit 60 moves the head 12 to the position of the capping unit 23 in the maintenance area MA, performs capping, and waits.

[0052] In this way, the control unit 60 can acquire a first detected temperature DH using the first sensor 15, and while moving the head 12 between the heating area HA and the maintenance area MA, it can heat and stop heating so that the head 12 reaches the target temperature TH. Furthermore, when the control unit 60 has capped the head 12 and is in standby mode, it may determine that the first detected temperature DH is not higher than the target temperature TH. In this case, the control unit 60 may return to the process of moving the head 12 from the position of the capping unit 23 in the maintenance area MA to the heating area HA (S101), heat the head 12, and continue the subsequent processes as described above.

[0053] Incidentally, the position of the capping unit 23 in the maintenance area MA can be the position where the head 12 is waiting before printing. On the other hand, the heating area HA is the position where the head 12 prints. The control unit 60 can also use the distance from the capping unit 23 to the heating region HA as the acceleration region for the carriage motor of the carriage 11 when the head 12 is printing. The control unit 60 does not need to separately secure an acceleration region for the carriage motor.

[0054] When the control unit 60 receives print data from an external device via the communication unit 52, it prints (S104) and then terminates the process. Specifically, the control unit 60 moves the head 12 from the maintenance area MA to the heating area HA, ejects ink from the head 12 based on the print data, and prints on the medium P supported by the platen 30. Furthermore, if the control unit 60 receives print data when the first detected temperature DH is not higher than the target temperature TH, it may temporarily suspend processing of the print data and print the suspended print data after the first detected temperature DH becomes higher than the target temperature TH. In this case, the control unit 60 may move the head 12 from the heating area HA to the maintenance area MA (S103), and as soon as the head 12 is separated from the platen 30, move the head 12 from the maintenance area MA to the heating area HA and perform printing (S104).

[0055] Here, referring to Figure 7, the relationship between the set temperature TP of the platen 30 and the target temperature TH of the head 12 will be explained. In the following, "head 12" refers to the nozzle plate 14 of the head 12. As described above, when the heater 31 heats the platen 30, vapor is generated from the ink adhering to the medium P supported by the platen 30, and rises towards the head 12 above. The amount of this vapor increases with the temperature of the platen 30. The amount of vapor that condenses on the head 12 is due to the temperature difference between the platen 30 and the head 12.

[0056] Therefore, in order to suppress the amount of vapor condensation in the head 12, the control unit 60 should set the target temperature TH of the head 12 to correspond to the set temperature TP of the platen 30. As shown in Figure 7, the control unit 60 processes using a first relational expression T1 such that the target temperature TH of the head 12 increases as the set temperature TP of the platen 30 increases. For example, the first relational equation T1 may be such that the target temperature TH of the head 12 is directly proportional to the set temperature TP of the platen 30. Alternatively, the first relational equation T1 may have multiple proportionality constants depending on the range of the set temperature TP. In this case, the first relational equation T1 shown in Figure 7 is represented as a line graph. The same applies to the second relational equation T2, which will be described later.

[0057] To suppress condensation, it is preferable that the temperature difference between the platen 30 and the head 12 be small. It is preferable that the target temperature TH of the head 12 be the same as the set temperature TP of the platen 30. However, in reality, a medium P is interposed between the platen 30 and the head 12. Therefore, the effect of the temperature difference between the platen 30 and the head 12 on condensation on the head 12 is mitigated. Consequently, the target temperature TH of the head 12 may be slightly lower than the set temperature TP of the platen 30. In the first relational equation T1 in Figure 7 and the second relational equation T2 described later, the target temperature TH of the head 12 is slightly lower than the set temperature TP of the platen 30. The head 12 can be prevented from being overheated.

[0058] The amount of vapor generated from the medium P increases in proportion to the temperature difference between the platen 30 and the head 12, as well as the amount of ink adhering to the medium P. For example, when the printing duty cycle is high, such as when white ink (W) is ejected across the entire surface of the medium P as the background color, the amount of vapor increases. To suppress condensation when the printing duty cycle is high, the control unit 60 should make the target temperature TH of the head 12 higher than that of the first relational expression T1. Specifically, as shown in Figure 7, the control unit 60 can process using a second relational expression T2 which makes the target temperature TH higher than that of the first relational expression T1.

[0059] When the second relational equation T2 is used, the temperature of the head 12 becomes higher, so the control unit 60 can suppress condensation more effectively than when the first relational equation T1 is used, even when the amount of steam increases. Furthermore, the control unit 60 can process data using multiple relational expressions with different target temperatures TH, in addition to the first relational expression T1 and the second relational expression T2, depending on the printing duty cycle. Furthermore, the control unit 60 can also process inks with different evaporation components using multiple relational expressions.

[0060] The first and second relational expressions, and other relational expressions, are stored in the storage unit 61. The control unit 60 can read these relational expressions from the storage unit 61 and calculate the target temperature TH of the head 12 from the set temperature TP of the platen 30. These relational expressions may also be stored as a table in the storage unit 61. The memory unit 61 also stores a formula or table for calculating the set temperature TP of the platen 30 from the ambient temperature, and the control unit 60 can read this formula and calculate the set temperature TP.

[0061] Furthermore, the amount of steam is also affected by the type and basis weight of the medium P. The control unit 60 may, for example, select either the first relational expression T1 or the second relational expression T2 to process the data according to the type and basis weight of the medium P. Furthermore, the control unit 60 can store the type of media P, basis weight, etc. in the storage unit 61 based on input from the user to the input / output unit 50 of the printing device 1, or instructions from an external device obtained by the communication unit 52. Based on this, the control unit 60 can, for example, select the second relational expression T2 when the type of media P or basis weight results in a large amount of steam.

[0062] The control unit 60 may also select the second relational expression T2 when the printing device 1 is used in a low-temperature environment or immediately after startup. Figure 7 shows examples of the first relational expression T1 and the second relational expression T2. ​​However, the control unit 60 may use multiple relational expressions similar to the first relational expression T1, in addition to the second relational expression T2, as described above, depending on the combination of conditions described above.

[0063] Thus, under the control of the control unit 60, the heater 31, which is the heating unit, heats the platen 30 according to the set temperature TP. The target temperature TH, which is a predetermined temperature for heating the head 12, is defined to vary with the set temperature TP. Furthermore, the target temperature TH is defined to be lower than the set temperature TP. Furthermore, as shown in Figure 7, the target temperature TH, which is a predetermined temperature, has a first predetermined temperature defined by the first relational expression T1 and a second predetermined temperature defined by the second relational expression T2. ​​The second predetermined temperature is set higher than the first predetermined temperature. The control unit 60 can heat the head 12 at either the first predetermined temperature or the second predetermined temperature.

[0064] Furthermore, the control unit 60 does not need to heat the print head 12 when printing nozzle check patterns to check the nozzles 13 or when printing patterns to adjust the ink color. This is because the amount of ink is often not enough to cause condensation on the print head 12. The print data for these prescribed patterns is stored in advance in the storage unit 61.

[0065] As described above, the printing apparatus 1 includes a head 12 that ejects liquid ink onto a medium P, a platen 30 that supports the medium P, a heater 31 which is a heating unit that heats the platen 30, a first sensor 15 which is a head temperature detection unit that detects the temperature of the head 12, a carriage 11 that supports the head 12 and is movable in the scanning direction via the top of the platen 30, and a control unit 60 that controls the heater 31 and the carriage 11. When the temperature detected by the first sensor 15 is below a predetermined target temperature TH, the control unit 60 moves the head 12 above the platen 30 using the carriage 11, and warms the head 12 with the platen 30 heated by the heater 31.

[0066] In this way, the printing apparatus 1 can warm the head 12 by moving the head 12 above the platen 30 heated by the heater 31. The temperature difference between the head 12 and the platen 30 becomes smaller. As a result, condensation of steam rising from the medium P adhering to the nozzle plate 14 of the head 12 is suppressed, and nozzle 13 ejection failure is suppressed. The printing apparatus 1 can suppress condensation on the print head 12 by warming the print head 12 using a platen 30 which has a heater 31 for drying the ink adhering to the medium P. The printing apparatus 1 does not require any new components to suppress condensation on the print head 12, and can suppress an increase in size.

[0067] Although embodiments have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may be modified, substituted, deleted, etc., as long as it does not depart from the spirit of this invention. For example, in the above description, the maintenance unit 20 was placed on the right side of the printing device 1, but it may also be placed on the left side. In this case, the arrangement of each unit within the maintenance unit 20, and the arrangement of the maintenance area MA and the heating area HA, will be the reverse of the above description. [Explanation of Symbols]

[0068] 1…Printing device, 10…Printing unit, 11…Carriage, 12…Head, 13…Nozzle, 14…Nozzle plate, 15…First sensor, 20…Maintenance unit, 21…Flushing unit, 22…Suction unit, 23…Capping unit, 30…Platen, 30a…Platen end, 31…Heater, 32…Second sensor, 50…Input / output unit, 60…Control unit, 61…Storage unit, DH…First detected temperature, DP…Second detected temperature, HA…Heating area, MA…Maintenance area, P…Media, S1…First scanning direction, S2…Second scanning direction, T1…First relation, T2…Second relation, TH…Target temperature, TP…Set temperature.

Claims

1. A head that dispenses liquid into the medium, A platen supporting the aforementioned medium, A heating section for heating the platen, A head temperature detection unit for detecting the temperature of the head, A carriage that supports the head and is movable in the scanning direction via the top of the platen, A control unit that controls the heating unit and the carriage, Equipped with, The printing apparatus is characterized in that, when the temperature detected by the head temperature detection unit is below a predetermined temperature, the control unit moves the head above the platen using the carriage and warms the head with the platen heated by the heating unit.

2. The printing apparatus according to claim 1, characterized in that the heating unit heats the platen according to a set temperature, and the predetermined temperature fluctuates according to the set temperature.

3. The printing apparatus according to claim 2, characterized in that the predetermined temperature is lower than the set temperature.

4. The printing apparatus according to claim 3, wherein the predetermined temperature comprises a first predetermined temperature and a second predetermined temperature higher than the first predetermined temperature, and the control unit heats the head by the first predetermined temperature or the second predetermined temperature.

5. The printing apparatus according to claim 1, further comprising a maintenance unit for maintaining the head, wherein the control unit moves the head to the maintenance unit by carriage when a predetermined time has elapsed while the head has been warmed, and performs maintenance on the head.

6. The printing apparatus according to claim 5, characterized in that the maintenance unit has a flushing unit in which the head performs a waste print of the liquid.

7. The printing apparatus according to claim 5, characterized in that the maintenance unit has a suction unit for sucking the liquid from the head.

8. A control method for a printing apparatus comprising: a head for dispensing liquid onto a medium; a platen for supporting the medium; a heating unit for heating the platen; a head temperature detection unit for detecting the temperature of the head; and a carriage that supports the head and is movable in the scanning direction via the top of the platen, A method for controlling a printing apparatus, characterized in that, when the temperature detected by the head temperature detection unit is below a predetermined temperature, the carriage moves the head above the platen, and the platen heated by the heating unit warms the head.

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