JP4879692B2 - Printing device - Google Patents

Description

  The present invention relates to a technique for applying a discharge liquid, and more particularly to a printing apparatus that can reliably clean a print head.

  Ink-jet printers are used in consumer and office applications, as well as color filters for liquid crystal display devices, alignment films, spacer coating, light emitting layers for organic EL devices, wiring for plasma display elements, and FPD fields. It is used for manufacturing, mounting wiring board manufacturing and the like.

  A plurality of ejection holes are provided on the bottom surface of the print head of the printing apparatus, and an organic material solution for an organic EL element or a spacer dispersion liquid for a liquid crystal display element is filled as an ejection liquid inside the print head, When discharged from the discharge holes and landed at a desired position on the surface of the printing object, an organic thin film can be formed and spacers can be arranged.

  In such an ink jet printing apparatus, if the surface is soiled by the discharge liquid discharged from the print head, a high-viscosity lump is formed in the discharge liquid due to drying, or if bubbles are involved, the discharge liquid is normal. If it is not discharged, printing failure occurs.

Therefore, countermeasures have been taken even in the prior art, and when a printing defect occurs, the inside of the print head was washed with a cleaning liquid, but the old discharge liquid could not be completely removed, and there were bubbles and high in the inside of the print head. There is a case in which a viscous mass remains, and if a new discharge liquid is filled in this state, there is a problem that printing defects cannot be solved.
Further, when the spacer dispersion liquid is discharged, if a transfer pump such as a screw pump is used, the spacer is crushed and the recovered discharged liquid cannot be reused.
JP 2001-1555 A JP 2003-231276 A

  The present invention was created in order to solve the above-described conventional technology, and provides a technology capable of reliably performing cleaning.

  Another object of the present invention is to provide a technique capable of cleaning a print head and piping without using a transfer pump.

In order to solve the above-described problems, the present invention provides a discharge liquid supply source tank in which discharge liquid is disposed, a cleaning liquid supply source tank in which cleaning liquid is disposed, a cleaning liquid recovery tank that collects cleaning liquid, and a discharge hole in a wall surface. When the discharge liquid is applied to the surface of a print object, the discharge liquid is supplied from the discharge liquid supply source tank to the print head, and the print target is discharged from the discharge hole. When cleaning the inside of the print head, the cleaning liquid is supplied from the cleaning liquid supply source tank to the print head and flows through the print head to clean the print head. some of the cleaning solution flowing through the is recovered in the cleaning solution recovery tank to fall from the discharge hole, the other part is recovered in the cleaning solution recovery tank through a pipe connected to said print head Configured urchin, the cleaning liquid recovery tank, the concentration measuring device for measuring the concentrations of the components of the ejection liquid contained in said cleaning liquid is connected printing apparatus.
The present invention includes a discharge liquid supply tank in which discharge liquid is disposed, a cleaning liquid supply tank in which cleaning liquid is disposed, a cleaning liquid recovery tank in which cleaning liquid is collected, and a print head in which discharge holes are provided on a wall surface. When the discharge liquid is applied to the surface of the print object, the discharge liquid is supplied from the discharge liquid supply source tank to the print head, and is discharged from the discharge hole to the print object. when cleaning the inside of the head, the cleaning liquid is supplied to the print head from the cleaning liquid supply source tank, the washed printing heads flowing in said print head, said cleaning liquid flows through the said print head one parts are recovered in the cleaning solution recovery tank to fall from the discharge hole, another part of the cleaning solution passes through a pipe that connects the washing liquid recovery tank and the print head, said cleaning solution recovery tank Is configured to be recovered, to measure the concentrations of the components of the ejection liquid to the contained in the cleaning liquid in the middle of any of the routes for transferring the cleaning liquid flows in the print head to the cleaning solution recovery tank This is a printing apparatus to which a density measuring device is connected.
The present invention includes a discharge liquid supply source tank in which discharge liquid is disposed, a cleaning liquid supply source tank in which cleaning liquid is disposed, a cleaning liquid recovery tank that collects cleaning liquid, a print head having a discharge hole provided on a wall surface, And a tray disposed at a position where the liquid pushed out from the print head falls, and when the discharge liquid is applied to the surface of the printing object, the discharge liquid is printed from the discharge liquid supply source tank. When cleaning the inside of the print head, the cleaning liquid is supplied from the cleaning liquid supply tank to the print head and flows through the print head. the print head is washed Te, the portion of the cleaning liquid flowing through the print head is transferred to the cleaning solution recovery tank is collected in the tray, the other part of the cleaning liquid, the print f Through a piping connecting de and with said washing liquid recovery tank is configured to be recovered in the cleaning solution recovery tank, the tray measures the concentrations of the components of the ejection liquid contained in said washing liquid This is a printing apparatus to which a density measuring device is connected.
The present invention includes a supply tank, the supply tank is connected to the print head, the discharge liquid supply source tank and the cleaning liquid supply source tank are connected to the supply tank, and a discharge in the discharge liquid supply source tank The printing apparatus is configured to supply the liquid and the cleaning liquid in the cleaning liquid supply source tank to the print head from the supply tank after being transferred into the supply tank.
In the present invention , a pressure reducing pump can be connected to the supply tank, the print head is disconnected from the supply tank, and either the discharge liquid supply tank or the cleaning liquid supply tank is connected to the supply tank. When the pressure inside the supply tank is reduced by the pressure reducing pump, the liquid disposed in the discharge liquid supply source tank connected to the supply tank or the cleaning liquid supply source tank connected to the supply tank is A printing device configured to be transferred to a supply tank.
In the present invention , a pressurizing pump is connectably connected to the supply tank, the supply tank is disconnected from the discharge liquid supply source tank and the cleaning liquid supply source tank, the supply tank is connected to the print head, When the inside of the supply tank is pressurized, the liquid in the supply tank is a printing apparatus configured to be transferred to the print head.
The present invention includes a discharge liquid recovery tank that recovers the discharge liquid, and when the discharge liquid is recovered, the discharge liquid in the print head is pushed out by the pressure pump, and the discharged discharge liquid is pushed out. Is a printing apparatus configured to collect the liquid in the discharge liquid collection tank.
The present invention is configured so that a suction pump can be connected to the discharge liquid recovery tank, and when the discharge liquid recovery tank and the print head are connected, the inside of the discharge liquid recovery tank is decompressed by the suction pump. In the printing apparatus, the liquid inside the print head is transferred to the inside of the discharge liquid recovery tank.
The present invention is configured such that a suction pump can be connected to the cleaning liquid recovery tank, and when the pressure inside the cleaning liquid recovery tank is reduced by the suction pump in a state where the cleaning liquid recovery tank and the print head are connected, the printing In the printing apparatus, the liquid inside the head is transferred to the inside of the cleaning liquid recovery tank.
The present invention has a control device in which a reference value is set, and the cleaning is terminated when the concentration of the component of the discharge liquid measured by the concentration measuring device is equal to or lower than the reference value. Device.

  According to the present invention, it is possible to remove the old discharge liquid from the print head and the supply tank, and the printing defect is eliminated. Since the discharge liquid can be discharged from the print head or supply tank without using a transfer pump, the discharge liquid can be reused even when a spacer dispersion liquid is used as the discharge liquid.

Reference numeral 1 in FIGS. 1A to 1D denotes a printing apparatus according to an example of the present invention. FIG. 1A is a plan view, and FIG. 1B is a side view of FIG. It is.
The printing apparatus 1 includes a table 11, a support unit 12 disposed on the table 11 so as to be separated from the surface of the table 11, and a print head 20 disposed on a surface of the support unit 12 facing the table 11. Have.

Reference numeral 7 in FIGS. 1A and 1B denotes a print object placed on one side of the support portion 12 on the table 11. The print object 7 is placed on the table 11 by a moving mechanism (not shown). It is configured to move up.
FIG. 1C shows a state in which the print object 7 moves while passing through a position facing the support unit 12, and FIG. 1D shows that the print object 7 faces the support unit 12. It shows a state in which it has passed through the position to be moved and moved to a position on the opposite side to the printing object 7 before the movement.

The print head 20 is connected to the discharge liquid supply system 40 and the discharge liquid recovery system 60. As described later, when the discharge liquid is supplied from the discharge liquid supply system 40, the print head 20 is filled with the discharge liquid. Is configured to do.
As shown in FIG. 4A, a plurality of discharge holes 25 are provided on the bottom surface of the print head 20.

  A discharge element (not shown here) such as a piezoelectric element is disposed inside the print head 20, and when the piezoelectric element operates in a state where the discharge liquid 45 is full, the discharge liquid is shown in FIG. As shown in FIG. 4C, the ink is ejected from the print head 20 as shown in FIG. When the discharge target is located immediately below the print head 20, the discharge liquid 45 lands on the print target.

  The print head 20 is movably supported by the support unit 12. The movement direction of the print head 20 is a direction perpendicular to the movement direction of the print object 7. When the print head 20 and the print object 7 are moved, the discharge liquid 45 is landed on a desired position of the print object 7. Can be made.

FIG. 3 shows the inside of the discharge liquid supply system 40 and the discharge liquid recovery system 60.
The discharge liquid supply system 40 includes a supply tank 41, a cleaning liquid supply source tank 42, a discharge liquid supply source tank 43, a decompression pump 56, and a pressurization pump 57. Reference numeral 59 in the figure is a regulator.

  The supply tank 41 is connected to the print head 20, the discharge liquid supply source tank 43, and the cleaning liquid supply source tank 42 via the supply side tank switching device 48, and operates the supply side tank switching device 48. Accordingly, any one of the print head 20, the discharge liquid supply source tank 43, and the cleaning liquid supply source tank 42 is connected to the supply tank 41. Reference numerals 52a and 52b in the figure are switching valves of the supply-side tank switching device 48, and the operation of the supply-side tank switching device 48 is to switch the switching valves 52a and 52b here.

  The supply tank 41 is connected with a decompression pump 56 and a pressurization pump 57 via a pump switching device 49, and either the decompression pump 56 or the pressurization pump 57 is connected to the supply tank 41. It is configured so that it can be connected. Reference numerals 51a to 51c in the figure indicate the opening / closing valves of the pump switching device 49, and the operation of the pump switching device 49 is here to open / close the opening / closing valves 51a to 51c.

A discharge liquid 45 is disposed in the discharge liquid supply source tank 43, and a cleaning liquid 46 is disposed in the cleaning liquid supply source tank 42.
The capacity of the supply tank 41 is smaller than the capacity of the discharge liquid supply source tank 43 and the cleaning liquid supply source tank 42, and the discharge liquid 45 and the cleaning liquid 46 are first arranged in the discharge liquid supply source tank 43 and the cleaning liquid supply source tank 42, respectively. And transferred to the supply tank 41 as described below.

  When the discharge liquid in the discharge liquid supply source tank 43 is transferred to the supply tank 41, the discharge liquid supply source tank 43 and the decompression pump 56 are connected to the supply tank 41, and the upper space in the supply tank 41 is removed by the decompression pump 56. When exhausted to a reduced pressure atmosphere, the discharge liquid 45 in the discharge liquid supply source tank 43 is sucked into the supply tank 41 from the supply port on the bottom surface of the supply tank 41.

  A liquid amount sensor 58a is connected to the supply tank 41, and the amount of the discharge liquid 45 in the supply tank 41 is detected by the liquid amount sensor 58a and transmitted to a control device (not shown).

  When a predetermined amount of the discharge liquid 45 is transferred into the supply tank 41, the control device controls the pump switching device 49, closes the on-off valve 51b between the decompression pump 56 and the supply tank 41, and connects the decompression pump 56 to the supply tank 41. When it is separated from the supply, the increase in the discharge liquid 45 in the supply tank 41 stops.

  In this state, the supply-side tank switching device 48 and the pump switching device 49 are operated, the print head 20 and the pressure pump 57 are connected to the supply tank 41, and the discharge liquid 45 level of the supply tank 41 by the pressure pump 57. When the upper space is pressurized, the discharge liquid 45 in the supply tank 41 is pressurized, flows toward the print head 20, and fills the print head 20.

When the discharge liquid 45 is filled in the print head 20, the supply tank 41 is connected to the decompression pump 56, and when the pressure in the supply tank 41 is reduced, the discharge liquid 45 in the print head 20 does not fall and enters the print head 20. Retained.
In this state, the discharge liquid 45 is discharged from the print head 20 onto the print object 7. When the discharge liquid 45 in the print head 20 decreases, the decrease is replenished from the supply tank 41.

A tray 55 is disposed outside the range in which the print object 7 moves and at a position where the print head 20 can arrive. FIG. 2 shows a state where the print head 20 is positioned on the tray 55.
When air bubbles are mixed in the print head 20, the air bubbles can be removed by pressurizing the inside of the print head 20 and forcibly discharging the discharge liquid 45.

When the print head 20 is positioned on the tray 55, the discharge liquid 45 discharged from the print head 20 is received by the tray 55.
A waste system 54 and a discharge liquid recovery system 60 are connected to the tray 55, and the discharge liquid discharged to the tray 55 can be discarded from the waste system 54. The reference numeral 51d in the figure indicates an on-off valve that connects the waste system 54 to the tray 55.

  Further, the discharge liquid discharged to the tray 55 may be recovered by the discharge liquid recovery system 60. The discharge liquid recovery system 60 will be described. The discharge liquid recovery system 60 includes a discharge liquid recovery tank 61, a cleaning liquid recovery tank 62, and a suction pump 65.

The discharge liquid recovery tank 61 and the cleaning liquid recovery tank 62 are connected to the print head 20 and the tray 55 via a recovery side tank switching device 66 and on-off valves 51e and 51f.
When the on-off valves 51e and 51f are in the open state, by operating the recovery side tank switching device 66, the discharge liquid recovery tank 61 and the cleaning liquid recovery tank 62 are connected to either the print head 20 or the tray 55, respectively. It is like that.
The reference numerals 52c and 52d in the figure indicate the switching valve of the recovery side tank switching device 66, and the operation of the recovery side tank switching device 66 is to switch the switching valves 52c and 52d here.
When the discharge liquid 45 is discharged from the print head 20 and landed on the surface of the print object 7, the on-off valve 51f is kept closed.

  The suction pump 65 is connected to the discharge liquid recovery tank 61 and the cleaning liquid recovery tank 62 via the switching valve 52e and the opening / closing valve 51g, and by operating the switching valve 52e with the opening / closing valve 51g open. The suction pump 65 is connected to one of the discharge liquid recovery tank 61 and the cleaning liquid recovery tank 62, and is configured to discard the gas inside the connected tank and depressurize the inside of the tank.

  When the discharge liquid 45 in the print head 20 and the discharge liquid 45 in the supply tank 41 are collected, the supply tank 41 and the print head 20 are connected and the supply tank 41 is opened to the atmosphere or the pressure pump 57 is connected. Then, the print head 20 is connected to the discharge liquid recovery tank 61.

  When the suction pump 65 is connected to the discharge liquid recovery tank 61 and operated, the discharge liquid 45 in the supply tank 41 and the print head 20 is recovered in the discharge liquid recovery tank 61. When the supply tank 41 is connected to the pressurizing pump 57, when the inside of the supply tank 41 is pressurized, the recovery speed is increased.

  The discharge liquid recovery tank 61 is provided with a liquid amount sensor 58b, and when the discharge liquid 45 in the supply tank 41 and the print head 20 is recovered in the discharge liquid recovery tank 61, the suction pump 65 and the discharge liquid recovery tank. The opening / closing valve 51g between the suction pump 61 and the suction pump 65 is closed, and the suction pump 65 is disconnected from the discharge liquid recovery tank 61.

On the discharge liquid supply system 40 side, when the decompression pump 56 and the cleaning liquid supply source tank 42 are connected to the supply tank 41 and the inside of the supply tank 41 from which the discharge liquid 45 has been discharged is decompressed by the decompression pump 56, the cleaning liquid supply source tank The cleaning liquid 46 is transferred from 42 to the inside of the supply tank.
On the other hand, on the discharge liquid recovery system 60 side, the on-off valve 51g is opened, the switching valve 52e is operated, the suction pump 65 is connected to the cleaning liquid recovery tank 62, and the connection between the print head 20 and the tray 55 is connected to the discharge liquid recovery tank. 61 is changed to the cleaning liquid recovery tank 62.

  On the discharge liquid supply system 40 side, when the cleaning liquid 46 is transferred to a position where the liquid level in the supply tank 41 is higher than the liquid level where the discharge liquid 45 was located, the supply tank 41 is connected to the pressure pump 57 and the print head. When the inside of the supply tank 41 is pressurized, the cleaning liquid 46 inside the supply tank 41 is pushed out of the discharge hole 25 by the pressure and falls onto the tray 55 after cleaning the inside of the print head 20. When ejected from the ejection holes 25, the ejection holes 25 are also cleaned.

  When the pressure in the cleaning liquid recovery tank 62 is reduced by the suction pump 65, the cleaning liquid 46 that has dropped on the tray 55 is recovered in the cleaning liquid recovery tank 62. At this time, the print head 20 is also connected to the cleaning liquid recovery tank 62, and when the cleaning liquid recovery tank 62 is depressurized, a part of the cleaning liquid 46 inside the print head 20 does not pass through the discharge holes 25, and the cleaning liquid recovery tank 62. 62 is recovered.

A concentration measuring device 53 a is attached to the cleaning liquid recovery tank 62. The concentration measuring device 53a is connected to the control device. The concentration measuring device 53a detects the content of solid components in the cleaning liquid 46 such as the solid components of the discharge liquid 45 dissolved in the recovered cleaning liquid 46.
When the discharge liquid 45 is a spacer dispersion liquid and the cleaning liquid 46 is a solvent that does not contain a spacer, the content of the spacer contained in the cleaning liquid 46 is detected by the concentration measuring device 53a.

A reference value is set in advance in the control device, and the measured concentration is compared with the reference value. If the measured value is higher than the reference value, cleaning is continued.
When the cleaning is continued, if the cleaning liquid 46 in the supply tank 41 is all sucked and does not become lower than the reference value even if it becomes empty, the supply tank 41 is connected to the cleaning liquid supply source tank 42 and the decompression pump 56. Then, the cleaning liquid 46 in the cleaning liquid supply source tank 42 is transferred to the supply tank 41, and the supply tank 41 is again filled with the cleaning liquid. Then, the supply tank 41 is connected to the print head 20 and the pressure pump 57, and a part is discharged. The liquid is ejected from the holes 25, and other parts are allowed to flow without passing through the discharge holes 25, and the supply tank 41, the piping, and the print head 20 are continuously cleaned.

The cleaning liquid 46 is repeatedly supplied into the supply tank 41 and the print head 20 is cleaned until the measured value is lower than the reference value. When the measured value is lower than the reference value, the cleaning is terminated.
When ending the cleaning, the cleaning liquid 46 in the supply tank 41 may be recovered to the cleaning liquid recovery tank 62 through the print head 20 or may be returned to the cleaning liquid supply tank 42.

  When the cleaning liquid in the supply tank 41, the print head 20, and the piping is removed, the on-off valves 51e and 51f between the discharge liquid recovery system 60 and the print head 20 are closed, and the discharge liquid 45 is supplied to the supply tank 41 as described above. After the transfer, the discharge liquid 45 is supplied from the supply tank 41 to the print head 20 and discharged onto the print object 7.

In the above description, the concentration measuring device 53a is provided in the cleaning solution recovery tank 62, and it is determined whether or not the cleaning is completed by changing the concentration of the cleaning solution measured by the concentration measuring device 53a. Reference numerals 53b and 53c in FIG. As shown in FIG. 2, a concentration measuring device is provided in a pipe connecting the print head 20 and the discharge liquid recovery system 60 and a pipe connecting the tray 55 and the cleaning liquid recovery tank 62, and the concentration measuring devices 53b and 53c measure the concentration. The end of cleaning may be determined by a change.
Similarly, a concentration measuring device 53d may be provided on the tray 55, and it may be determined whether or not cleaning has been completed based on a change in the concentration of the cleaning liquid 46 measured by the concentration measuring device 53d.

In short, in addition to providing the cleaning liquid in the cleaning liquid recovery tank 62, the concentration measuring devices 53 a to 53 d can be provided in the path through which the cleaning liquid 46 that has flowed through the print head 20 is recovered in the cleaning liquid recovery tank 62.
The case where the discharge liquid recovery tank 61 and the cleaning liquid recovery tank 62 are connected to the same suction pump 65 has been described above. However, the present invention is not limited to this, and the discharge liquid recovery tank 61 and the cleaning liquid recovery tank 62 are connected. May be connected to separate suction pumps.

  The cleaning liquid supply source tank 42 and the discharge liquid supply source tank 43 may be connected to separate supply tanks 41 via on-off valves without using the switching device 48. Further, the cleaning liquid supply source tank 42 and the discharge liquid supply source tank 43 may be connected to separate decompression pumps and pressurization pumps via an on-off valve without using the switching device 48.

  In the above embodiment, the discharge liquid recovery tank 61 and the cleaning liquid recovery tank 62 are provided separately. However, when the recovered discharge liquid 45 is not reused, as shown in FIG. The cleaning liquid 46 and the discharge liquid 45 may be recovered in the cleaning liquid recovery tank 62.

  In this case, the liquid amount sensor 58c and the concentration measuring device 53a may be provided in the cleaning liquid recovery tank 62, respectively, but the discharge liquid 45 is recovered before the cleaning liquid 46 is recovered in the cleaning liquid recovery tank 62, and the cleaning liquid Since the solid components and the spacers of the cleaning liquid 46 in the recovery tank 62 remain at a high concentration, concentration measuring devices 53b and 53d are provided on the pipe 55 for connecting the print head 20 and the cleaning liquid recovery tank 62 and the tray 55 to change the concentration. Should be measured. Note that the concentration measuring device 53 c may be provided in a pipe connecting the tray 55 to the cleaning liquid recovery tank 62 instead of the tray 55.

  When the discharge liquid 45 is discharged to the tray 55 to eliminate the clogging of the discharge holes 25, or when the concentration of the liquid discharged to the tray 55 is clearly high, such as when the cleaning liquid 46 starts to be discharged to the tray 55 The discharge liquid 45 and the cleaning liquid 46 discharged to the tray 55 may be discarded from the disposal system 54.

(A): a plan view for explaining a printing apparatus used in the present invention, (b) to (d): a side view for explaining a step of moving a printing object. The top view for demonstrating the state which has arrange | positioned the print head on a tray Schematic diagram for explaining the relationship between the print head, the discharge liquid supply system, and the discharge liquid recovery system (A)-(c): Sectional drawing for demonstrating the process of discharging discharge liquid Schematic diagram for explaining another example of the discharge liquid recovery system

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printing apparatus 7 ... Print target object 20 ... Print head 25 ... Discharge hole 41 ... Supply tank 45 ... Discharge liquid 46 ... Cleaning liquid 42 ... Cleaning liquid supply source tank 43 ... Discharge liquid supply source tank 53a to 53d …… Concentration measuring device 55 …… Tray 56 …… Decompression pump 57 …… Pressure pump 61 …… Discharge liquid recovery tank 62 …… Cleaning liquid recovery tank 65 …… Suction pump

Claims (10)

A discharge liquid supply source tank in which the discharge liquid is disposed;
A cleaning liquid supply tank in which the cleaning liquid is disposed;
A cleaning liquid recovery tank for recovering the cleaning liquid;
And a print head provided with discharge holes on the wall surface,
When applying the discharge liquid on the surface of the print object, the discharge liquid is supplied from the discharge liquid supply source tank to the print head, and is discharged from the discharge hole to the print object.
When cleaning the inside of the print head, the cleaning liquid is supplied from the cleaning liquid supply source tank to the print head, and flows through the print head to clean the print head.
Part of the cleaning liquid that has flowed through the print head falls from the discharge hole and is recovered in the cleaning liquid recovery tank, and the other part is recovered in the cleaning liquid recovery tank through a pipe connected to the print head. Configured to be
A printing apparatus in which a concentration measuring device for measuring a concentration of a component of the discharge liquid contained in the cleaning liquid is connected to the cleaning liquid recovery tank. A discharge liquid supply source tank in which the discharge liquid is disposed;
A cleaning liquid supply tank in which the cleaning liquid is disposed;
A cleaning liquid recovery tank for recovering the cleaning liquid;
And a print head provided with discharge holes on the wall surface,
When applying the discharge liquid on the surface of the print object, the discharge liquid is supplied from the discharge liquid supply source tank to the print head, and is discharged from the discharge hole to the print object.
When cleaning the inside of the print head, the cleaning liquid is supplied from the cleaning liquid supply source tank to the print head, and flows through the print head to clean the print head.
A portion of the cleaning liquid that has flowed through the print head falls from the discharge holes and is recovered in the cleaning liquid recovery tank .
The other part of the cleaning liquid is configured to be recovered in the cleaning liquid recovery tank through a pipe connecting the print head and the cleaning liquid recovery tank.
A printing apparatus in which a concentration measuring device for measuring the concentration of the component of the discharge liquid contained in the cleaning liquid is connected to any of the paths for transferring the cleaning liquid flowing in the print head to the cleaning liquid recovery tank. . A discharge liquid supply source tank in which the discharge liquid is disposed;
A cleaning liquid supply tank in which the cleaning liquid is disposed;
A cleaning liquid recovery tank for recovering the cleaning liquid;
A print head with discharge holes on the wall;
A tray disposed at a position where the liquid pushed out of the print head falls,
When applying the discharge liquid on the surface of the print object, the discharge liquid is supplied from the discharge liquid supply source tank to the print head, and is discharged from the discharge hole to the print object.
When cleaning the inside of the print head, the cleaning liquid is supplied from the cleaning liquid supply source tank to the print head, and flows through the print head to clean the print head.
Some of the cleaning solution flowing through the said printing head is transferred to the cleaning solution recovery tank is collected in the tray,
The other part of the cleaning liquid is configured to be recovered in the cleaning liquid recovery tank through a pipe connecting the print head and the cleaning liquid recovery tank.
A printing apparatus in which the tray is connected to a concentration measuring device for measuring the concentration of the component of the discharge liquid contained in the cleaning liquid. A supply tank, the supply tank is connected to the print head, the discharge liquid supply source tank and the cleaning liquid supply source tank are connected to the supply tank,
The discharge liquid in the discharge liquid supply source tank and the cleaning liquid in the cleaning liquid supply source tank are configured to be supplied from the supply tank to the print head after being transferred into the supply tank. The printing apparatus according to any one of claims 1 to 3. The supply tank is configured to be connected to a decompression pump,
When the print head is disconnected from the supply tank, either the discharge liquid supply source tank or the cleaning liquid supply source tank is connected to the supply tank, and the pressure inside the supply tank is reduced by the pressure reducing pump, the supply tank The printing apparatus according to claim 4, wherein the liquid disposed in the discharge liquid supply source tank connected or the cleaning liquid supply source tank connected to the supply tank is transferred to the supply tank. . A pressure pump is connected to the supply tank so as to be connectable,
Separating the supply tank from the discharge liquid supply source tank and the cleaning liquid supply source tank;
Connecting the supply tank to the print head;
The printing apparatus according to claim 4, wherein when the inside of the supply tank is pressurized, the liquid in the supply tank is transferred to the print head. A discharge liquid recovery tank for recovering the discharge liquid;
7. When collecting the discharge liquid, the discharge liquid in the print head is pushed out by the pressure pump, and the discharged discharge liquid is collected in the discharge liquid collection tank. Printing device. A suction pump can be connected to the discharge liquid recovery tank,
When the inside of the discharge liquid collection tank is depressurized by the suction pump in a state where the discharge liquid collection tank and the print head are connected, the liquid inside the print head is transferred to the inside of the discharge liquid collection tank. The printing apparatus according to claim 7, which is configured as follows. A suction pump can be connected to the cleaning liquid recovery tank,
In a state where the cleaning liquid recovery tank and the print head are connected, when the pressure inside the cleaning liquid recovery tank is reduced by the suction pump, the liquid inside the print head is transferred to the inside of the cleaning liquid recovery tank. The printing apparatus according to any one of claims 1 to 7. A control device having a reference value set, wherein the cleaning is terminated when the concentration of the component of the discharge liquid measured by the concentration measuring device is equal to or lower than the reference value. Item 10. The printing device according to any one of Items 9 to 9.

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