JP5264616B2 - Printer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer equipped with an ink supply device that stably supplies ink to a printer head by preventing ink from flowing into inner pressure control valves. <P>SOLUTION: The printer is equipped with an ink supply device for supplying ink to printer heads 52a, 52b. The ink supply device includes: sub tanks 53a, 53b, a supply pump 61, a pressure adjusting pump 66, a liquid level detecting substrate, and a controller. A liquid ink is branched and supplied to the sub tanks 53a, 53b, to which the printer heads 52a, 52b are connected respectively. The sub tanks 53a, 53b are each connected to the pressure adjusting pump 66 through the inner pressure control valves 55a, 55b. When the ink is supplied to the sub tanks 53a, 53b, the inner pressure control valves corresponding to the sub tanks with the lower limit height position detected are controlled for opening while the inner pressure control valves corresponding to other sub tanks are controlled for closing. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a printer apparatus including an ink supply device that supplies ink to a printer head that performs printing by discharging ink.

  In the printer apparatus, the printer head is generally mounted on a carriage that is moved relative to the print medium, and ejects ink from ejection nozzles formed on the lower surface while being moved relative to the print medium. It is configured to perform printing by adhering to a print medium in a predetermined pattern. In the printer apparatus configured as described above, when the internal pressure of the printer head becomes higher than the atmospheric pressure, the ink is pushed out from the discharge nozzle and dropped onto the print medium, causing a problem of so-called “dropping”. As a method for solving this problem, a configuration in which a subtank in which a small-capacity ink chamber is formed is provided. During printing, by adjusting the internal pressure of the sub tank to a slightly negative pressure slightly lower than the atmospheric pressure, ink is supplied from the sub tank to the printer head, thereby forming a meniscus on the discharge nozzle and preventing dripping. It is like that.

For example, ink supply means for supplying ink from an ink cartridge (main tank) to the sub tank and pressure adjusting means for adjusting the internal pressure of the ink chamber are connected to the sub tank. The ink supply device is mainly composed of the sub tank, the ink supply means and the pressure adjusting means. For example, FIG. 1 of Patent Document 1 discloses a configuration in which an ink supply tube 4 and an exhaust tube 6 are connected to a sub tank 3 connected to a recording head 1.
With this configuration, ink is supplied from the main tank 5 via the ink supply tube 4, and the exhaust pump 11 is driven to apply a negative pressure to the sub tank 3.

  Recently, for the purpose of shortening the printing time, a configuration has been developed in which printer heads that eject the same ink are mounted adjacent to each other on a carriage and printing is performed using these printer heads. FIG. 8 shows a conventional printing unit 500 in which two printer heads 540a and 540b that discharge the same ink are mounted on a carriage (not shown) so as to be adjacent to the left and right. Sub tanks 530a and 530b are connected to the printer heads 540a and 540b, respectively. The ink stored in the ink cartridge 510 is supplied to the sub tanks 530a and 530b by the supply pump 520. The sub tanks 530a and 530b are connected to a pressure regulating pump 560 via internal pressure control valves 550a and 550b, respectively.

  With such a configuration, at the time of printing, while maintaining the internal pressure of the sub tanks 530a and 530b at a slight negative pressure by the pressure adjusting pump 560, the sub tanks 530a and 530a, Ink is supplied to 530b. Specifically, when it is detected that the ink storage amount has reached the lower limit in one of the sub tanks 530a and 530b, the supply pump 520 maintains the internal pressure of the sub tanks 530a and 530b at a slightly negative pressure. Driven for a predetermined time, substantially the same amount (including the same amount) of ink is supplied to each of the sub tanks 530a and 530b.

JP 2002-240310 A

  By the way, it is not always the case that printing is performed by always ejecting ink from the printer heads 540a and 540b in the same manner. For example, there is a case where ejection control is performed such that the amount of ink ejected per unit time is larger in the printer head 540b than in the printer head 540a. In this case, it is detected in the sub tank 530b that the ink storage amount has reached the lower limit, and ink is supplied to each of the sub tanks 530a and 530b. At this time, since the inside of the sub tanks 530a and 530b is maintained at a slight negative pressure, substantially the same amount of ink is supplied to each of the sub tanks 530a and 530b. At this time, ink is supplied to the sub tank 530a even though a sufficient amount of ink is stored, and ink exceeding the capacity of the sub tank 530a may be supplied. Then, there is a problem that ink overflowing from the sub tank 530a flows into the internal pressure control valve 550a and it is difficult to adjust the internal pressure of the sub tank 530a (printer head 540a).

  The present invention has been made in view of the above problems, and an ink supply device that can stably supply ink to a printer head by preventing ink from flowing into an internal pressure control valve while having a relatively simple configuration. It is an object of the present invention to provide a printer apparatus provided.

  In order to achieve the above object, a printer device according to the present invention includes an ink supply device that supplies liquid ink to a printer head that performs printing by discharging liquid ink in a state of facing a print medium, and the ink supply device includes: The liquid ink connected to the printer head and temporarily supplied from a main tank (for example, the ink cartridge 60 in the embodiment) in which the liquid ink is stored is temporarily stored in an ink chamber formed therein, and then transferred to the printer head. A sub-tank to be supplied; ink supply means for supplying liquid ink from the main tank to the ink chamber (for example, the supply pump 61 in the embodiment); and pressure adjusting means for adjusting the internal pressure of the ink chamber (for example, in the embodiment) Pressure regulating pump 66) and a liquid level for detecting a liquid level height position of the liquid ink stored in the ink chamber Performing drive control of the ink supply means and drive control of the pressure adjusting means according to the detection results detected by the discharge means (for example, the liquid level detection substrates 72a and 72b in the embodiment) and the liquid level detection means Control means (for example, the controller 43 in the embodiment), the liquid ink stored in the main tank is branched and supplied to the plurality of sub tanks, and the printer head is connected to each of the plurality of sub tanks. Each of the plurality of sub-tanks is arranged corresponding to each of the plurality of sub-tanks and is connected to the pressure regulating means via an internal pressure control valve that is controlled to open and close by the control means. And when the liquid ink is supplied to the sub tank, the control means includes the liquid level of the plurality of sub tanks. Opening control of the internal pressure control valve corresponding to the lower limit amount sub tank in which the lower limit height position is detected by the output means, and causing the negative pressure by the pressure adjusting means to act on the ink chamber of the lower limit amount sub tank, and Of the plurality of subtanks, the internal pressure control valve corresponding to the other subtanks excluding the lower limit amount subtank is controlled to be closed, and the internal pressure adjustment by the pressure adjusting means is restricted for the ink chambers of the other subtanks. .

  In the printer apparatus, the printer head is mounted on a carriage that is relatively moved with respect to a print medium, and a plurality of the printer heads that discharge the same liquid ink that is branched and supplied from the main tank includes: A configuration mounted adjacent to the carriage is preferred.

  In the printer device according to the present invention, each of the plurality of sub-tanks is connected to the pressure adjusting means via the internal pressure control valve, and when the ink is supplied to the sub-tank, the sub-tank whose ink storage amount has reached the lower limit While the corresponding internal pressure control valve is opened to apply a negative pressure, the internal pressure control valve corresponding to the sub-tank in which an appropriate amount of other ink is stored is closed to prevent the negative pressure from being applied. With this configuration, the ink can be selectively supplied by applying a negative pressure to the sub tank with the lower limit amount of ink, and the corresponding internal pressure control valve is closed to the sub tank storing the appropriate amount of ink. Can be prevented from being supplied. Therefore, it becomes possible to supply ink only to the sub-tank that has reached the lower limit amount and needs to be supplied with ink. Can be prevented from flowing into.

  In the printer apparatus described above, a configuration in which a plurality of printer heads that discharge the same liquid ink are mounted on the carriage so as to be adjacent to each other is preferable. For example, when printing is performed by simultaneously ejecting the same ink from two printer heads mounted on the carriage adjacent to each other, the printing time is shorter than when printing is performed using one printer head. Can be halved. Therefore, it is possible to improve work efficiency as a whole.

1 is a perspective view of a printer apparatus to which the present invention is applied. It is the perspective view which showed the printing unit periphery of the said printer apparatus. FIG. 4 is a diagram illustrating an ink supply path to a printer head. It is sectional drawing of the IV-IV part in FIG. FIG. 3 is a control system diagram of the printer apparatus. It is sectional drawing of a subtank (when ink is supplied). It is a flowchart when supplying ink to a sub tank. It is a figure showing a conventional ink supply path.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience of explanation, the arrow directions shown in the drawings are defined as front and rear, left and right, and up and down. First, the configuration of the printer device 10 according to the present invention will be described with reference to FIGS. In the following description, the printer device 10 configured to print on the plate-like print medium B using ultraviolet curable ink that is cured by being irradiated with ultraviolet rays will be described as an example.

  As shown in FIG. 1, the printer device 10 mainly includes a support portion 2 provided at a lower portion and a printing portion 3 attached to the support portion 2 so as to be movable back and forth. The support portion 2 is mainly composed of a plurality of support legs 11, a table 12 supported horizontally by the support legs 11, and front and rear moving mechanisms 20 and 30 provided at the left and right ends of the table 12 and extending in the front-rear direction. . A decompression chamber (not shown) is formed on the lower side (back side) of the table 12, and the surface of the table 12 and the decompression chamber communicate with each other by a plurality of supply / discharge holes (not shown) penetrating vertically. Has been. A supply / discharge blower (not shown) can suck air in the decompression chamber or send air into the decompression chamber. For example, by sucking air in the decompression chamber, air is sucked from the supply / discharge hole to the decompression chamber, and the print medium B placed on the surface of the table 12 can be adsorbed to the table 12 and fixed.

  The front and rear moving mechanisms 20 and 30 are configured to move the printing unit 3 straight back and forth with respect to the table 12 by operating each of them in synchronization. Note that various well-known techniques can be used as the back-and-forth movement mechanisms 20 and 30, and description thereof is omitted in this specification.

  The printing unit 3 mainly includes a main body unit 40 that extends over the table 12 and extends to the left and right, and a printing unit 50. The printing unit 50 is attached to a guide rail 42 that extends in the left and right directions inside the main body 40. An operation unit 41 including operation switches and display devices is provided on the left front side of the main body 40. In addition, a controller 43 is mounted inside the main body 40 on the left end side, and the controller 43 is electrically connected to the operation unit 41 and each component described later. The controller 43 receives an operation signal from the operation unit 41 and outputs an operation signal to each constituent member to perform operation control.

  Specifically, as shown in FIG. 5, the controller 43 receives detection results detected on liquid level detection substrates 72 a, 72 b, which will be described later, and the printer head 52, right ultraviolet irradiation device 54 </ b> R, left ultraviolet irradiation device. 54L, internal pressure control valves 55a, 55b, etc., supply pump 61, pressure adjusting pump 66, forward / backward moving mechanisms 20, 30, and left / right moving mechanism 44 for reciprocating the printing unit 50 to the left and right, and so on. It is configured.

  As shown in FIG. 2, the printing unit 50 mainly includes a carriage 51, a plurality of (for example, eight) printer heads 52, a plurality of (for example, eight) sub tanks 53, a right ultraviolet irradiation device 54R, and a left ultraviolet irradiation device 54L. Composed. The printing unit 50 is moved left and right along the guide rail 42 by the left and right moving mechanism 44. Note that various well-known techniques can be used as the left-right moving mechanism 44, and description thereof is omitted in this specification.

  The carriage 51 is attached to the guide rail 42 so as to be movable left and right. The carriage 51 is a mounting base for the printer head 52, the sub tank 53, the right ultraviolet irradiation device 54R, and the left ultraviolet irradiation device 54L. The printer head 52 is formed with a plurality of ejection nozzles (not shown) for ejecting ink downward on the lower surface. In addition, two printer heads 52 that discharge ink of the same color are mounted on the carriage 51 so as to be adjacent to the left and right. FIG. 2 illustrates a configuration in which two printer heads 52 that eject magenta (M), yellow (Y), cyan (C), and black (K) inks are mounted in order from the right side. doing. Each of the printer heads 52 is configured to be able to print at a resolution of 150 dpi, for example. In this embodiment, the configuration using the printer heads 52 for four colors is illustrated, but a configuration using multicolor printer heads 52 of six colors or more may be used in addition to this configuration.

  The sub tank 53 is provided so as to correspond to each of the printer heads 52 and is mounted above the printer head 52. The sub tank 53 is configured to temporarily store ink therein and to supply the stored ink to the printer head 52 according to the amount of ink discharged from the printer head 52. The detailed structure of the sub tank 53 will be described later. In the following description, the configuration of the printer heads 52a and 52b that discharge magenta (M) ink and the sub tanks 53a and 53b connected to the printer heads 52a and 52b will be mainly described. Note that the printer head 52 and the sub tank 53 that eject ink of other colors have the same configuration as the printer heads 52a and 52b and the sub tanks 53a and 53b described below.

  Each of the right ultraviolet ray irradiation device 54R and the left ultraviolet ray irradiation device 54L has a built-in light source (for example, LED) capable of emitting ultraviolet rays, and the ultraviolet rays from the light source are emitted downward. . In addition, it is also possible to use a metal halide lamp etc. instead of said LED as a light source which irradiates an ultraviolet-ray.

  FIG. 3 shows the printer heads 52a and 52b and the sub tanks 53a and 53b extracted from the printing unit 50 shown in FIG. As can be seen from FIG. 3, a supply tube 62 is connected to the upper front side of each of the sub tanks 53 a and 53 b (near the height position of a full detection sensor 73 </ b> F described later). The supply tube 62 is mounted on the lower side of the table 12, for example, and is connected to an ink cartridge 60 in which magenta ink is stored. A supply pump 61 is disposed in the supply tube 62. By driving the supply pump 61, magenta ink is supplied from the ink cartridge 60 to each of the sub tanks 53a and 53b. Each of the printer heads 52 a and 52 b is independently controlled by the controller 43 to eject ink.

  The pressure regulating tube 65 connected to the pressure regulating pump 66 is provided with internal pressure control valves 55a and 55b made up of, for example, two-way solenoid valves, corresponding to the sub tanks 53a and 53b. The upper part of the sub tank 53a and the internal pressure control valve 55a are connected by the branch tube 64a, and the upper part of the sub tank 53b and the internal pressure control valve 55b are connected by the branch tube 64b. A part of the pressure adjusting tube 65 and the internal pressure control valves 55 a and 55 b are mounted on the carriage 51.

  By the way, when the insides of the printer heads 52a and 52b are in a positive pressure state, the ink is pushed out from the ejection nozzles, causing a problem of “dropping off”. Therefore, in order to avoid this problem, control is performed to drive the pressure adjustment pump 66 and open the internal pressure control valves 55a and 55b during printing (see FIG. 4). By doing so, a negative pressure is applied to the inside of the sub tanks 53a and 53b, and a meniscus can be formed in the discharge nozzles of the printer heads 52a and 52b.

  FIG. 4 shows a cross-sectional view of the sub tanks 53a and 53b. The sub tank 53a and the sub tank 53b have the same configuration. Here, the configuration of the sub tank 53a will be described with reference to FIG. The sub tank 53a is mainly configured by a tank body 70, a guide wall 71, a liquid level detection substrate 72a, and a float 74. The tank body 70 is formed in a substantially rectangular parallelepiped using, for example, a black resin material, and an ink chamber 79 for storing ink is formed therein. By forming the black resin material in this way, it is possible to reduce the entry of light (ultraviolet light) into the tank body 70 and to prevent the ink stored in the ink chamber 79 from being cured. The sub tank 53b is provided with a liquid level detection board 72b for detecting the liquid level of the ink chamber 79 in the sub tank 53b.

  The guide wall 71 is formed to extend vertically so as to divide the ink chamber 79. The liquid level detection board 72a is configured by mounting a full detection sensor 73F on the top, a middle detection sensor 73M on the middle, and a lower limit detection sensor 73L on the bottom. The float 74 floats on the ink and is always positioned on the liquid surface, and a magnet (not shown) is fixed to the float 74. The float 74 moves up and down substantially straight while being guided by the guide wall 71 according to the amount of ink (liquid level) stored in the ink chamber 79.

  For example, when the float 74 falls to the position of the lower limit detection sensor 73L, the magnetic force of the magnet is detected by the lower limit detection sensor 73L, and it is detected that the ink stored in the ink chamber 79 has decreased to the lower limit amount. Similarly, when the magnetic force is detected by the full detection sensor 73F, the ink chamber 79 is full of ink, and when the magnetic force is detected by the middle detection sensor 73M, about half of the ink is in the ink chamber 79. It is detected that it is stored. This detection result is output to the controller 43 via the liquid level detection board 72a.

  The configuration of the printer device 10 has been described above. Hereinafter, the operation of the printer apparatus 10 when printing on the print medium B will be described.

  First, as shown in FIG. 1, the printing medium B is placed on the table 12 and the air in the decompression chamber is sucked so that the printing medium B is attracted to the table 12 and fixed. Then, the printing unit 3 is moved forward with respect to the table 12 by the front and rear moving mechanisms 20 and 30 so that the printing unit 50 and the printing medium B are opposed to each other. In this state, while the printing unit 50 is moved left and right by the left and right moving mechanism 44, ink is ejected from the printer head 52 and ultraviolet rays are emitted from the right ultraviolet ray irradiation device 54R and the left ultraviolet ray irradiation device 54L. By doing so, the ink can be adhered to the printing medium B in a desired pattern, and the adhered ink can be cured to perform printing.

  When ink is ejected from the printer head 52, for example, magenta ink with a resolution of 150 dpi is ejected from each of the printer heads 52a and 52b. As a result, printing with a resolution of 300 dpi is performed in a short time (for example, one printer Compared with the case where printing with a resolution of 300 dpi is performed using the head 52a, the printing can be performed in about half the time).

  While performing the above operation, the printing unit 50 is reciprocated left and right along the guide rail 42 a predetermined number of times, and then the printing unit 3 is moved forward by a predetermined distance by the front and rear moving mechanisms 20 and 30. Then, while the printing unit 50 is reciprocated left and right a predetermined number of times, ink ejection and ultraviolet irradiation are performed. By repeating such an operation, desired printing can be performed on the entire print medium B.

  When printing is performed as described above, ink stored in the sub tank 53 is supplied to the printer head 52 according to, for example, the amount of ink discharged from the printer head 52. As described above, when ink is supplied from the sub tank 53 to the printer head 52, the ink stored in the sub tank 53 decreases. When the ink stored in the sub-tank 53 decreases to the lower limit amount, the ink is supplied from the ink cartridge 60, and a constant amount of ink is always maintained.

  The operation when ink is supplied from the ink cartridge 60 to the sub tank 53 as described above will be described below along the flowchart shown in FIG.

  Depending on the image shape or the like to be printed, each of the printer heads 52a and 52b may be independently controlled to discharge, and the ink discharge amount per unit time may differ between the printer head 52a and the printer head 52b. For example, as shown in FIG. 4, in the state where the liquid level heights of the sub-tanks 53a and 53b are substantially the same, the printer head 52b is controlled so as to continuously discharge ink, while the printer head 52a is almost the same. Control may be performed so as not to eject ink. The operation described below will be described by exemplifying a case where such discharge control is performed.

  When printing is continued while the above-described ejection control is performed, the ink in the sub tank 53a does not decrease, while the ink in the sub tank 53b gradually decreases and the liquid level (float 74) falls (see FIG. 6). Then, in step S101 shown in FIG. 7, it is detected that the float 74 of the sub tank 53b has dropped to the position of the lower limit detection sensor 73L and has decreased to the lower limit amount on the liquid level detection substrate 72b. At this time, the controller 43 receives the detection result from the liquid level detection board 72b.

  Subsequently, the process proceeds to step S102, where the controller 43, based on the detection result input in step S101, stores the sub-tank 53a in which an appropriate amount of ink is stored (the lower limit amount is not detected) as shown in FIG. Control to close the corresponding internal pressure control valve 55a is performed. By doing so, the ink chamber 79 of the sub tank 53a is blocked from the pressure adjusting pump (outside air). In step S101, the internal pressure control valve 55b corresponding to the sub tank 53b in which the lower limit amount is detected is left open to apply a negative pressure to the ink chamber 79 of the sub tank 53b.

  In step S103, the controller 43 drives the supply pump 61 by outputting an operation signal to the supply pump 61. Thereby, the ink of the ink cartridge 60 is sent to the sub tanks 53a and 53b through the supply tube 62. At this time, ink is hardly supplied to the ink chamber 79 of the sub-tank 53a that is blocked from the outside air, while ink is automatically supplied to the ink chamber 79 of the sub-tank 53b where the negative pressure acts and ink tends to flow. Is supplied (step S104).

  As a result, most of the ink supplied from the ink cartridge 60 can be selectively supplied to the ink chamber 79 of the sub tank 53b that has been reduced to the lower limit amount (needed to be supplied with ink). It is. Also, ink is hardly supplied to the ink chamber 79 of the sub tank 53a where an appropriate amount of ink is stored and does not need to be supplied. Therefore, it is possible to reliably prevent the occurrence of a situation in which the ink exceeding the capacity of the ink chamber 79 is supplied and the overflowed ink flows into the internal pressure control valve, and the internal pressure adjustment to the sub tank 53 (printer head 52) can be accurately performed. it can. Therefore, the printer head 52 can perform high-quality printing without causing dropout or ejection failure.

  The supply pump 61 is driven for a predetermined time by an operation signal from the controller 43. When the magnetic force is not detected by the lower limit detection sensor 73L after driving for a certain time (when the float 74 in the sub tank 53b is located between the middle detection sensor 73M and the lower limit detection sensor 73L), the ink is supplied. finish. On the other hand, after the supply pump 61 is driven for a fixed time, if the magnetic force is still detected by the lower limit detection sensor 73L, the supply pump 61 is driven again for a fixed time. In this way, ink is supplied so that the float 74 in the sub tank 53b is positioned between the middle detection sensor 73M and the lower limit detection sensor 73L.

  It should be noted that no matter how many times the supply pump 61 is driven, if the float 74 in the sub tank 53b is not located between the middle detection sensor 73M and the lower limit detection sensor 73L (the position of the lower limit detection sensor 73L remains unchanged). The controller 43 determines that the ink cartridge 60 is empty. In this case, the controller 43 outputs a signal to the operation unit 41 to display, for example, “cartridge replacement” and prompt the operator to replace the ink cartridge 60.

  Subsequently, the process proceeds to step S105, where control is performed to open the internal pressure control valve 55a corresponding to the sub tank 53a closed in step S102, and the flow of supplying ink to the ink chamber 79 of the sub tank 53b is completed. By doing so, it is possible to store an appropriate amount of ink in each of the sub tanks 53a and 53b and to apply a negative pressure to each ink chamber 79. Therefore, ink can be stably supplied from the sub tanks 53a, 53b to the printer heads 52a, 52b, and printing can be continued.

  In the above-described embodiment, the configuration is illustrated in which two printer heads 52 (for example, the printer heads 52a and 52b) that discharge the same ink are adjacent to each other. However, the present invention is limited to this configuration. It is not something. For example, the present invention can be similarly applied to a configuration in which three or more printer heads 52 that discharge the same ink are adjacent to each other.

  In the above-described embodiment, the configuration example in which the present invention is applied to the two-axis printer head moving type printer device 10 has been described. However, the present invention is not limited to the printer device having such a configuration. For example, the present invention can also be applied to a printer device of a uniaxial printing medium movement type, a uniaxial printer head movement type, and a biaxial printing medium movement type printer device. Further, the ink to be used is not limited to the ultraviolet curable ink, and the present invention can be applied to a printer apparatus using another type of ink such as water-based ink.

B Print medium 10 Printer device 43 Controller (control means)
51 Carriage 52 Printer head 53 Sub tank 55a Internal pressure control valve 55b Internal pressure control valve 60 Ink cartridge (main tank)
61 Supply pump (ink supply means)
66 Pressure regulating pump (pressure regulating means)
72a Liquid level detection substrate (liquid level detection means)
72b Liquid level detection substrate (Liquid level detection means)
79 Ink chamber

Claims (2)

A printer device including an ink supply device that supplies liquid ink to a printer head that performs printing by discharging liquid ink in a state of facing a print medium,
The ink supply device comprises:
A sub-tank connected to the printer head and temporarily storing liquid ink supplied from a main tank in which liquid ink is stored in an ink chamber formed therein and supplying the ink to the printer head;
Ink supply means for supplying liquid ink from the main tank to the ink chamber;
Pressure adjusting means for adjusting the internal pressure of the ink chamber;
A liquid level detection means for detecting a liquid level height position of the liquid ink stored in the ink chamber;
Control means for performing drive control of the ink supply means according to the detection result detected by the liquid level detection means, and drive control of the pressure adjusting means,
The liquid ink stored in the main tank is branched and supplied to the plurality of sub tanks, and the printer head is connected to each of the plurality of sub tanks.
Each of the plurality of sub tanks is connected to the pressure regulating means via an internal pressure control valve that is disposed corresponding to each of the plurality of sub tanks and is controlled to be opened and closed by the control means.
When liquid ink is supplied to the sub tank,
The control means includes
Among the plurality of sub tanks, the pressure control is performed on the ink chamber of the lower limit amount sub-tank by opening the internal pressure control valve corresponding to the lower limit amount sub tank whose lower limit height position is detected by the liquid level detection unit. While applying negative pressure by means,
Among the plurality of sub tanks, the internal pressure control valve corresponding to the other sub tanks excluding the lower limit amount sub tank is controlled to be closed, and the internal pressure adjustment by the pressure adjusting means is restricted for the ink chambers of the other sub tanks. A printer apparatus characterized by: The printer head is mounted on a carriage that is moved relative to a print medium,
The printer apparatus according to claim 1, wherein a plurality of the printer heads that discharge the same liquid ink that is branched and supplied from the main tank are mounted adjacent to the carriage.

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