JP2005088525A - Inkjet printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printing apparatus which has no system open to the atmospheric air except a head in order to hold deaeration ink properties of an ink in an ink passage while an ink water level in a main tank is easily adjusted, and performs a large amount of printing by one ink feeding as an industrial printing apparatus. <P>SOLUTION: The inkjet printing apparatus comprises an inkjet head having a plurality of nozzles jetting ink liquid drops in the same direction as the gravity direction, a bag-like main tank feeding the ink to the head and filled with a deaerated ink, an ink feeding pipeline system for feeding the ink to the head from the bag-like main tank, a plurality of ink on-off valve additionally provided on a part of the ink feeding pipeline system, and an ink feeding means extended and arranged in the ink feeding pipeline system. In this inkjet printing apparatus, the ink feeding means for feeding the ink into the bag-like main tank with an ink liquid level measuring means in the bag-like main tank, and an inclined plate for finely adjusting the water level of the ink in the bag-like main tank so as to make the water level of the head always higher by an arbitrary position than the water level of the bag-like main tank, are provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an industrial inkjet apparatus capable of printing in a downward direction and capable of printing a large amount with a single ink supply.

  2. Description of the Related Art Conventionally, there is a printing apparatus in which a print head faces downward and an ink supply path is a tube (see, for example, Patent Document 1). In this example, an air release part is required in the main tank. In order to achieve an ink path that does not have an air release system, it is necessary to make the ink tank into a bag shape, but there are also printing apparatuses that make the ink tank into a bag shape and do not allow air to enter the ink tank (for example, patents) Reference 2).

  Further, a configuration in which the ink tank can be replaced so that ink can be supplied (for example, see Patent Document 3), and a method for measuring the ink water level by opening the ink chamber to the atmosphere (see, for example, Patent Document 4) can also be seen. .

  Furthermore, a method of filling an ink bag with ink and using it for printing is also shown (for example, see Patent Document 5). In order to always install a bag-shaped ink tank that does not open to the atmosphere and replenish ink with another ink container, it is necessary to know the ink water level in the ink tank. doing. However, considering the purge operation for printing, ink replenishment, or recovery when nozzles are not ejected while adjusting the fine ink water level of the head, it is not easy to accurately adjust the pressure of the main tank by pressure increase / decrease.

JP 2002-234180 A

JP-A-7-17047 Japanese Patent Application Laid-Open No. 11-157098 JP 2002-120374 A JP 2000-141687 A

  The problem to be solved by the present invention is to maintain the degassing ink property of the ink in the ink path while easily adjusting the ink water level of the main tank. An object of the present invention is to enable a large amount of printing to be continuously performed with a single ink supply as a printing apparatus for printing. It is another object of the present invention to provide a printing apparatus that enables ink supply to a main tank during printing and avoids interruption of printing due to ink supply.

  In order to achieve the above object, according to the first aspect of the present invention, an ink jet head having a plurality of nozzles for ejecting ink droplets in the same direction as the direction of gravity and an ink supplied to the head and degassed are filled. A bag-shaped main tank, an ink supply line system for supplying ink from the bag-shaped main tank to the head, a plurality of ink on-off valves attached to a part of the ink supply line system, and the ink supply An ink jet printing apparatus comprising an ink replenishing means extending in a pipeline system, and an ink replenishing means and a head for replenishing the bag main tank together with an ink water level measuring means in the bag main tank An inclined plate is provided for finely adjusting the water level of the bag-shaped main tank so that the water level is always higher than the water level of the bag-shaped main tank by an arbitrary position.

  In the second aspect of the invention, the ink level of the head when printing is held so as to be 10 mm to 30 mm above the ink level of the main tank.

  Furthermore, in the invention of claim 3, the capacity of the bag-shaped main tank is set to a large capacity of at least 300 cc to 1 liter.

Further, in the invention of claim 4, the ink replenishing means for the bag-shaped main tank is constituted by a detachable replenishing tank, a bag-shaped main tank, an ink replenishing pipe connecting the replenishing tank, and an electromagnetic valve capable of opening and closing the ink supply.
Furthermore, in the invention of claim 5, the ink water level measuring means of the bag-shaped main tank is carried on the upper surface of the main tank, and a movable thin plate with one end locked, a water level sensor partition plate attached to the movable thin plate, A water level sensor and a lower limit water level sensor were used.

  Further, in the invention of claim 6, there is provided a bag-shaped sub ink tank that is smaller than the bag-shaped main tank and can secure a water level substantially equal to the water level of the bag-shaped main tank in the ink supply conduit system between the bag-shaped main tank and the head. Configured. This can be achieved by providing another bag-shaped sub-ink tank at a position where the water level is substantially equal to the water level of the bag-shaped main tank.

According to the present invention, an inkjet head having a plurality of nozzles that eject ink droplets in the same direction as the direction of gravity, a bag-like main tank filled with degassed ink supplied to the inkjet head, and the bag An ink supply line system for supplying ink from the main tank to the head, a plurality of ink on-off valves attached to a part of the ink supply line system, and the ink supply line system In an ink jet printing apparatus comprising an ink replenishing means, an ink replenishing means for replenishing ink to the bag-shaped main tank together with an ink water level measuring means for the bag-shaped main tank and a water level of the head are always in the bag-shaped main tank. An inclined plate is provided to finely adjust the water level of the bag-like main tank so that it is arbitrarily higher than the water level. And the ink dripping from the head can automatically replenish the ink and within a movable range of the head in a state, air does not flow back into the head broken meniscus of the head.

  Further, since the ink level of the head at the time of printing is kept 10 mm to 30 mm above the ink level of the main tank, it is possible to always keep the printing conditions optimal.

  In addition, since the capacity of the bag-shaped main tank is at least 300 cc to 1 liter, continuous printing is possible and it can be used as an industrial printing apparatus.

Also, the ink supply means for the bag-shaped main tank is composed of a detachable supply tank, an ink supply pipe connecting the bag-shaped main tank and the supply tank, and an electromagnetic valve that can open and close the ink supply. It could be a replenishment device.
Further, the ink water level measuring means of the bag-shaped main tank is composed of a movable thin plate carried on the upper surface of the main tank and locked at one end, a water level sensor partition plate attached to the movable thin plate, and upper and lower limit water level sensors. Therefore, the ink water level measuring device could be simplified.

  In addition, a bag-shaped sub-ink tank is configured in the ink supply line system between the bag-shaped main tank and the head, which is smaller than the bag-shaped main tank and can secure a water level substantially equal to the water level of the bag-shaped main tank. Ink supply from the ink replenishment tank to the main tank is possible, and a printing apparatus capable of continuous mass printing without interrupting printing due to ink supply can be provided.

  An embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic configuration diagram illustrating an inkjet printing apparatus 10.

  As shown in FIG. 1, an inkjet printing apparatus 10 includes heads 11a, 11b,... 11z having a plurality of nozzles that can be printed downward, and a filter unit 13 that removes foreign matters in the ink. 13 and the head 11 are connected by a tube 12. The filter unit 13 is connected to a manifold a (16) arranged at the highest position by a plurality of tubes 15. The manifold a (16) is connected to a manifold b (32) that branches into a plurality of tubes 31 and increases the ink feeding capacity.

Further, the ink jet printing apparatus 10 includes a main tank 39 for supplying ink to the head 11, an ink supply tank 38, and an ink supply pipe 45 for transferring ink in the ink supply tank 38 to the main tank 39. And an ink pipe 46 connecting the main tank 39 and the manifold 32 to measure the remaining amount of ink in the electromagnetic valve a (34), the electromagnetic valve b (36), the electromagnetic valve c (37), and the main tank 39. A thin plate 40 mounted on the upper portion of the main tank, an ink sensor 43, and a partition plate 42 fixed and attached to the end of the thin plate 40 for on / off of the ink sensor. Reference numeral 44 denotes an inclined plate on which a main tank is mounted so that the ink water level can be finely adjusted. The inclined plate 44 can be rotated up and down at the right end in the figure, but is fixed after the ink water level is determined.
Air bubble vents 14, 17, and 33 are attached to the upper portions of the filter unit 13, the manifold a (16), and the manifold b (32) to collect and collect the air bubbles contained in the connected tubes. 35 and 41 are manual stoppers.

  Reference numeral 20 (inside the frame) indicates means for moving a part of the head 11, the tube a12, the filter unit 13 and the tube b15 in the direction of gravity. Similarly, 21 (inside the frame) indicates means for moving the gravity direction moving means 20, the manifold a (16), and a part of the tube c (31) in the horizontal direction.

  In FIG. 1, during printing, the head 11 can be moved to a predetermined position for printing by the horizontal direction moving means 21 and the gravity direction moving means 20. During printing, the manual stop plug 35, the electromagnetic valve a34, and the electromagnetic valve b36 are opened, and the electromagnetic valve c37 is closed. When the ink in the main tank is reduced and the ink level partition plate 42 indicates the lower limit position of the ink sensor 43, the solenoid valve a34 is closed and the solenoid valve b36 and the solenoid valve c37 are opened. Since the replenishing tank 38 is arranged so that the water level is higher than that of the main tank 39, the ink is injected from the replenishing tank 38 into the main tank 39.

  Further, when ink is supplied to the main tank and indicates the upper limit position of the ink sensor 43, the ink supply to the main tank can be stopped by closing the electromagnetic valve c37. In order to continue printing, the electromagnetic valve a34 may be opened. If the three solenoid valves and ink sensor signals are automatically managed by a control board (not shown), automatic ink supply is possible.

  In this example, a 1 liter aluminum bag with a plastic coating was used for the main tank. When the ink is full, the bag-shaped main tank used in the present invention has a height of about 40 mm even when placed horizontally, the height is about 30 mm when the ink is about 500 cc, and the height is high when the amount of ink is reduced to 100 cc. Therefore, the on / off position of the ink sensor 43 can be set according to the height of the main tank. That is, the bag-shaped ink tank used in the present invention has a size having an appropriate thickness so that the height can be appropriately changed by increasing or decreasing the ink content.

  This device cannot easily check the ink level in the main tank. Therefore, a method for checking the ink level of the main tank and a method for setting the ink level will be described below.

  FIG. 2 is a schematic U-shaped tube for explaining the ink water level in the main tank 39. The water level can be measured even if a pressure gauge (manometer) is attached instead of the U-shaped tube. From the middle of the ink supply pipe 46 (actually, if a bubble does not enter, the pipe and tube at any position are the same even if the U-shaped tube is erected). Columns are generated and the water level can be measured.

  Now, when the head at the printing position is set to the water level zero position and the ink water level amount is measured, as shown in FIG. 3, the water level changes depending on the ink remaining amount in the main tank 39, and the ink remaining amount increases. It can be seen that the water level does not become the same when the remaining amount of ink decreases. This is because of the rigidity of the bag of the main tank, when the ink is supplied from the replenishing tank 38 to the main tank, the main tank tries to push out the ink, so that the water level becomes high, and conversely when the ink is discharged. This is because the ink water level drops in order to suck ink back.

  From the past trials, it has been found that the ink tank has a good printability when it is -10 mm to -30 mm higher than the head water level during printing.

  Here, the factors that determine the ink level in the main tank include the remaining amount of ink in the main tank, whether ink is being supplied / discharged, and then tilting / supplying the main tank supply port upward Should it be tilted so that the mouth is down, there is also the weight of the thin plate 40 that rests on the main tank.

  In the present embodiment, first, the main tank is slightly tilted by the inclined plate 44 and the supply port is slightly inclined, the thin plate placed on the main tank is suppressed to about 50 to 100 gr, and the ink remaining amount of the main tank 39 is about 400 gr. The installation position of the main tank where the ink water level was −30 mm was found. Thereafter, the remaining amount of ink in the main tank when the ink level was -10 mm was determined. Further, the difference between the upper limit and the lower limit of the remaining amount of ink is the ink replenishment amount that can be supplied at one time, and the ink amount that can be continuously printed.

  In this apparatus, the amount of ink that can be continuously printed is 300 gr. However, the amount of ink that can be continuously printed can be easily increased by changing the bag size of the main tank or the inclination angle of the bag.

  As described above, the remaining ink amount and ink water level of the main tank, and the positional relationship between the partition plate 42 fixed to the upper end of the thin plate 40 and the ink sensor 43 are prepared in advance as data, and the data is used. Thus, the ink remaining amount and the ink water level of the main tank can be calculated only by the position of the partition plate 42.

As another embodiment, a method for continuing printing while supplying ink to the main tank will be described.
A bag-like ink tank smaller in size than the main tank (called a sub ink tank) is attached at the position of the manifold b (32), and the water level of the sub ink tank is adjusted to the water level of the main tank considering the height of the attachment position.
When the water level of the main tank 39 approaches the lower limit during printing, the solenoid valve a34 is closed and printing is continued, and the solenoid valve b36 and the solenoid valve c37 are opened to supply ink from the ink supply tank 38 to the main tank 39. When the ink in the main tank is full, the solenoid valve c37 is closed, and then the solenoid valve a34 and the solenoid valve b36 are opened, so that the ink lost from printing is supplied from the main tank to the sub ink tank and the printing ink is used. Can be continuously supplied to the head.
In the case of the configuration of this embodiment, the ink supply is normally completed within 1 minute to 3 minutes, so the ink amount in the sub ink tank may be a capacity that can compensate for the ink amount for 3 minutes. In this embodiment, a 100 cc ink bag can be used.
The present invention is not limited to this embodiment, and the inclination of the inclined plate can be changed as appropriate according to the capacity of the ink tank and the water head difference from the ink jet head.

It is a block diagram of an inkjet printing apparatus. It is a simulation diagram for explaining the ink water level of the ink tank. It is an ink water level graph.

Explanation of symbols

10 is an ink jet printing apparatus, 11 is a downward head, 34 is an electromagnetic valve a, 36 is an electromagnetic valve b, 37 is an electromagnetic valve c, 38 is an ink supply tank, 39 is a main tank, 40 is a thin plate, 42 is a partition plate, 43 Denotes an ink sensor, 44 denotes an inclined plate, 45 denotes an ink supply pipe, and 46 denotes an ink pipe.

Claims (6)

An inkjet head having a plurality of nozzles that eject ink droplets in the same direction as the direction of gravity, a bag-shaped main tank filled with degassed ink supplied to the head, and the head from the bag-shaped main tank An ink supply line system for supplying ink to the ink supply apparatus, a plurality of ink on-off valves attached to a part of the ink supply line system, and ink replenishment extending to the ink supply line system In an inkjet printing apparatus comprising:
The water level of the bag-shaped main tank is set so that the water level of the head and the ink supply means for supplying ink to the bag-shaped main tank together with the ink water level measuring means in the bag-shaped main tank is always higher than the water level of the bag-shaped main tank. An ink jet printing apparatus comprising an inclined plate for fine adjustment.   2. An ink jet printing apparatus according to claim 1, wherein the ink water level of the head when printing is maintained 10 mm to 30 mm above the ink water level of the main tank.   2. The industrial inkjet printing apparatus according to claim 1, wherein the capacity of the bag-shaped main tank is at least 300 cc to 1 liter.   2. The ink jet printing apparatus according to claim 1, wherein the ink supply means for the bag-shaped main tank comprises a detachable supply tank, a bag-shaped main tank, an ink supply pipe connecting the supply tank, and an electromagnetic valve capable of opening and closing the ink supply. The ink water level measuring means of the bag-shaped main tank comprises a movable thin plate carried on the upper surface of the main tank and locked at one end thereof, a water level sensor partition plate attached to the movable thin plate, and upper and lower limit water level sensors. The inkjet printing apparatus according to 1. 2. The ink jet printing according to claim 1, further comprising a bag-like sub ink tank in the ink supply pipe line system between the bag-like main tank and the head, which is smaller than the bag-like main tank and can secure a water level substantially equal to the water level of the bag-like main tank. apparatus.

Images