JP7327331B2 - inkjet printer - Google Patents

Description

The present invention relates to an inkjet printing apparatus that prints by ejecting ink from nozzles of a head.

When using an ink in which particle components (pigments, metal particles, etc.) are dispersed and printing is performed by an inkjet printing device, it is an important issue to suppress sedimentation and agglomeration of the ink particle components in the inkjet printing device. become. Sedimentation and agglomeration of ink particle components can cause the generation of coarse particles and fluctuations in ink density. These coarse particles can clog the nozzles of the head, making printing impossible, or the ink density can fluctuate, degrading print quality. This is because there is a risk that

Japanese Patent Application Laid-Open No. 2002-200002 discloses an inkjet printing apparatus that suppresses sedimentation and agglomeration of ink particle components. FIG. 13 shows an inkjet printing apparatus 1000 of Patent Document 1. As shown in FIG.

An inkjet printing device 1000 includes a tank 101 , a head 102 and a pump 103 . The head 102 includes an inlet 102a for introducing ink, a nozzle 102b for ejecting ink, and an outlet 102c for ejecting ink not ejected from the nozzle 102b. A head 102 and a pump 103 are arranged in a head circulation pipe 104 . The tank 101 and the head circulation pipe 104 are connected by a supply pipe 105 .

By driving the pump 103 , the ink 106 a stored in the tank 101 is supplied to the head circulation pipe 104 via the supply pipe 105 . The ink 106b supplied to the head circulation pipe 104 is circulated through the head circulation pipe 104 by driving the pump 103 and discharged from the nozzles 102b of the head 102 for printing.

The ink jet printing apparatus 1000 circulates the ink 106a in the head circulation pipe 104, thereby suppressing sedimentation and agglomeration of the particle components dispersed in the ink.

JP 2012-139949 A

In the inkjet printing apparatus 1000, the ink circulating in the head circulation pipe 104 is prevented from new sedimentation and agglomeration of particle components. However, when sedimentation or agglomeration of particle components occurs in the tank 101 or the supply pipe 105, the coarse particles cannot be removed from the ink, and the ink circulating in the head circulation pipe 104 contains coarse particles. As a result, there is a risk that the nozzle 102b of the head 102 will be clogged, making printing impossible, or that the ink density will fluctuate and print quality will deteriorate.

The present invention has been made to solve the above-described conventional problems, and as a means thereof, an inkjet printing apparatus according to a first embodiment of the present invention includes a first ink supply port, a first ink reservoir, a first tank having a first ink outlet; a head having an inlet for introducing ink; nozzles for ejecting ink; and outlets for ejecting ink not ejected from the nozzles; A first head circulation pipe connecting a first pump having a first suction port for sucking and a first ejection port for ejecting ink, the first ejection port of the first pump, and the inlet of the head a second head circulation pipe connecting the discharge port of the head and the first suction port of the first pump, a first ink outlet of the first tank, a first suction port of the first pump, and , an arbitrary position of the second head circulation pipe, a first upstream port and a first downstream port, and passes from the first upstream port to the first downstream port. and a first filter arranged in the supply pipe for filtering the ink to be discharged, and the filter is not arranged in the second head circulation pipe.

An inkjet printing apparatus according to a second aspect of the present invention includes a first tank having a first ink supply port, a first ink reservoir, and a first ink outlet, an inlet for introducing ink, a head having nozzles for ejecting ink and discharge ports for discharging ink not ejected from the nozzles; a first suction port for sucking ink; and a first ejection port for ejecting ink. A first head circulation pipe connecting the pump, the first discharge port of the first pump, and the inlet of the head; Supply connecting at least one of the 2-head circulation pipe, the first ink outlet of the first tank, the first suction port of the first pump, and an arbitrary position of the second head circulation pipe a first filter having a first upstream port and a first downstream port and arranged in the supply pipe for filtering ink passing from the first upstream port to the first downstream port; The flow resistance from the discharge port of the first pump to the first suction port of the first pump is defined as the first flow resistance, and the flow resistance from the first ink outlet of the first tank to the first suction port of the first pump is defined as , a second flow resistance, the second flow resistance is 10 times or more as large as the first flow resistance.

An inkjet printing apparatus according to a third aspect of the present invention includes a first tank having a first ink supply port, a first ink reservoir, and a first ink outlet, an inlet for introducing ink, a head having nozzles for ejecting ink and discharge ports for discharging ink not ejected from the nozzles; a first suction port for sucking ink; and a first ejection port for ejecting ink. A first head circulation pipe connecting the pump, the first discharge port of the first pump, and the inlet of the head; a second pump having a 2-head circulation pipe, a second suction port for sucking ink, and a second ejection port for ejecting ink; a first ink outlet of the first tank; 2 suction port; a second tank circulation pipe connecting the second discharge port of the second pump and the first ink supply port of the first tank; a supply pipe connecting an arbitrary position of the tank circulation pipe and at least one of the first suction port of the first pump and an arbitrary position of the second head circulation pipe; and a first upstream port. a first filter arranged in the supply pipe for filtering ink passing from the first upstream port to the first downstream port; is not arranged, and a filter is not arranged at the position of the first tank circulation pipe from the first ink outlet of the first tank to the part where the supply pipe is connected. do.

An inkjet printing apparatus according to a fourth aspect of the present invention includes a first tank having a first ink supply port, a first ink reservoir, and a first ink outlet, an inlet for introducing ink, a head having nozzles for ejecting ink and discharge ports for discharging ink not ejected from the nozzles; a first suction port for sucking ink; and a first ejection port for ejecting ink. A first head circulation pipe connecting the pump, the first discharge port of the first pump, and the inlet of the head; a second pump having a 2-head circulation pipe, a second suction port for sucking ink, and a second ejection port for ejecting ink; a first ink outlet of the first tank; 2 suction port; a second tank circulation pipe connecting the second discharge port of the second pump and the first ink supply port of the first tank; a supply pipe connecting an arbitrary position of the tank circulation pipe and at least one of the first suction port of the first pump and an arbitrary position of the second head circulation pipe; and a first upstream port. a first downstream port, and a first filter disposed in the supply pipe for filtering ink passing from the first upstream port to the first downstream port; The flow resistance up to the second suction port is the third flow resistance, and the flow resistance from the first ink outlet of the first tank to the second suction port of the second pump is the fourth flow resistance. Sometimes, the third flow path resistance is ten times or more the value of the fourth flow path resistance.

In the inkjet printing apparatus of the present invention, printing impossibility due to clogging of head nozzles, etc., deterioration of print quality due to fluctuations in ink density, entry of air bubbles into ink, leakage of ink from head nozzles, etc. is suppressed. there is

1 is an explanatory diagram showing an inkjet printer 100 according to a first embodiment; FIG. It is an explanatory view showing ink jet printer 110 concerning modification 1 of a 1st embodiment. It is an explanatory view showing the ink jet printer 120 concerning modification 2 of a 1st embodiment. FIG. 11 is an explanatory diagram showing an inkjet printer 130 according to Modification 3 of the first embodiment; FIG. 11 is an explanatory diagram showing an inkjet printer 140 according to Modification 4 of the first embodiment; It is an explanatory view showing an inkjet printer 200 according to a second embodiment. FIG. 11 is an explanatory diagram showing an inkjet printing apparatus 210 according to Modification 1 of the second embodiment; FIG. 11 is an explanatory diagram showing an inkjet printing apparatus 300 according to a third embodiment; FIG. 11 is an explanatory diagram showing an inkjet printer 310 according to Modification 1 of the third embodiment; It is an explanatory view showing ink jet printer 400 concerning a 4th embodiment. FIG. 11 is an explanatory diagram showing an inkjet printing device 410 according to Modification 1 of the fourth embodiment; FIG. 12 is an explanatory diagram showing an inkjet printing device 420 according to modification 2 of the fourth embodiment; 1 is an explanatory diagram showing an inkjet printing apparatus 1000 disclosed in Patent Document 1; FIG.

Embodiments for carrying out the present invention will be described below with reference to the drawings.

Each embodiment is an example of an embodiment of the present invention, and the present invention is not limited to the content of the embodiment. Moreover, it is also possible to combine the contents described in different embodiments, and the contents of the implementation in that case are also included in the present invention. In addition, the drawings are intended to aid understanding of the specification, and may be schematically drawn, and the drawn components or the ratio of dimensions between the components may not be the same as those described in the specification. The proportions of those dimensions may not match. In addition, there are cases where constituent elements described in the specification are omitted in the drawings, or where the number of constituent elements is omitted.

[First Embodiment]
FIG. 1 shows an inkjet printer 100 according to the first embodiment. However, FIG. 1 is an explanatory diagram of the inkjet printing apparatus 100 .

In the following, first, the outline of the inkjet printing apparatus 100 will be described, and then detailed description of each component will be given.

It is important to note that (a) the first filter 5 is provided in the supply pipe 12 (described later) and (b) the second head circulation pipe 9 (described later) is not provided with a filter. Characterized.

The inkjet printing device 100 includes a first tank 1 , a head 2 , a first pump 3 , a first filter 5 and a stage 7 . In addition, FIG. 1 also shows the ink 50 and the substrate 60 to be printed.

The first tank 1 has a third ink supply port 1c, a first ink reservoir 1d, and a first ink outlet 1e. Also, the third ink supply port 1c is closed by a lid 1f. Note that the tank is not limited to the first tank 1, and another tank may be provided. For example, a main tank may be provided separately from the first tank 1 as a sub-tank.

The head 2 includes an inlet 2a for introducing ink, a plurality of nozzles 2b for ejecting ink, and an outlet 2c for ejecting ink not ejected from the nozzles 2b. A stage 7 is arranged at a position facing the nozzle 2 b of the head 2 . A printed material 60 is placed on the stage 7 .

The first pump 3 includes a first suction port 3a for sucking ink and a first ejection port 3b for ejecting ink.

The first filter 5 has a first upstream port 5a and a first downstream port 5b, and filters ink passing from the first upstream port 5a to the first downstream port 5b.

A first discharge port 3 b of the first pump 3 and an inlet port 2 a of the head 2 are connected by a first head circulation pipe 8 . A discharge port 2 c of the head 2 and a first suction port 3 a of the first pump 3 are connected by a second head circulation pipe 9 .

The first ink outlet 1 e of the first tank 1 and the second head circulation pipe 9 are connected by a supply pipe 12 . A connection point of the supply pipe 12 to the second head circulation pipe 9 is defined as a first connection point J1. However, the supply pipe 12 may be directly connected to the first suction port 3 a of the first pump 3 instead of being connected to the second head circulation pipe 9 .

A first filter 5 is arranged in the supply pipe 12 . The first filter 5 is arranged with the first upstream port 5a on the first tank 1 side and the first downstream port 5b on the second head circulation pipe 9 side.

The inkjet printer 100 is used, for example, as follows.

First, the ink 50 is filled from the third ink supply port 1c of the first tank 1 into the first ink storage portion 1d and stored. Particle components such as pigments and metal particles may be dispersed in the ink 50 . In the following description, the symbol "50" of the ink 50 may be omitted in order to avoid complication.

Next, the first pump 3 is driven. As a result, the ink stored in the first ink reservoir 1d flows from the first ink outlet 1e through the supply pipe 12, the first filter 5, the supply pipe 12 again, and the second head circulation pipe 9. It is sucked into the first suction port 3a of the first pump 3 through the order. The driving force (suction force, discharge force) of the first pump 3 is appropriately adjusted. The first pump 3 is a pump that sucks ink from the first tank 1, and also a pump that circulates ink through a head circulation path (a first head circulation pipe 8 and a second head circulation pipe 9), which will be described later. is. That is, to the first suction port 3a of the first pump 3, the ink supplied from the first tank 1 via the supply pipe 12 and the ink not discharged from the nozzle 2b of the head 2 but discharged from the discharge port 2c The ink is added and sucked at the first connection point J1 of the second head circulation pipe 9 .

When the ink flowing from the first tank to the second head circulation pipe 9 via the supply pipe 12 contains coarse particles generated by sedimentation or agglomeration of particle components such as pigments and metal particles. is removed by the first filter 5 .

On the other hand, the ink sucked into the first suction port 3a of the first pump 3 is ejected from the first ejection port 3b, and flows through the first head circulation pipe 8, the head 2, and the second head circulation pipe 9 in this order. Then, it is again sucked into the first suction port 3a of the first pump 3. That is, the ink always circulates through the first pump 3, the first head circulation pipe 8, the head 2, the second head circulation pipe 9, and the first pump 3 in this order. Therefore, even if particle components such as pigments and metal particles are dispersed in the ink, sedimentation and agglomeration of the particle components are suppressed. Incidentally, the ink circulation path composed of the first head circulation pipe 8 and the second head circulation pipe 9 may be called a head circulation path.

In the head 2, ink is ejected from the nozzles 2b toward the printing material 60 to perform printing. The ink that has decreased due to printing is supplied from the first tank 1 to the second head circulation pipe 9 via the first tank circulation pipe 10 and the supply pipe 12 .

Next, details of each component will be described.

Although the material of the first tank 1 is arbitrary, for example, metal such as stainless steel or resin such as polypropylene can be used as the material of the inside of the first ink reservoir 1d. Although the capacity of the first tank 1 is also arbitrary, it can be, for example, 500 mL to 4000 mL. The shape of the first tank 1 is also arbitrary, but for example, the shape of the inside of the first ink reservoir 1d can be a cylindrical bottom surface with a mortar-shaped or conical slope added. . With this shape, the ink can be discharged smoothly from the first ink outlet 1e. It is also preferable that the first tank 1 has an internal air pressure adjustment mechanism, an ink amount sensor, a temperature control mechanism, a stirring mechanism, and the like.

The first head circulation pipe 8, the second head circulation pipe 9, and the supply pipe 12 may be made of any material. For example, metal such as stainless steel or resin such as Teflon (registered trademark) may be used. can. Although the shape and dimensions of the pipe are arbitrary, for example, a cylindrical pipe with an inner diameter of about 1 mm to 20 mm can be used. In addition, it is preferable that the inner surface does not have a portion such as a corner portion or a concave portion where the ink tends to stay.

For example, a tube pump, a rotary pump, a reciprocating pump, or the like can be used as the first pump 3 . It is preferable that the flow rate be adjustable. For example, it is preferable that the liquid has a suction and discharge capability of about 1 mL/min to 50 mL/min.

Although the material of the first filter 5 is arbitrary, for example, a metal such as stainless steel or a resin such as cellulose can be used. The mesh size of the first filter 5 is also arbitrary, but can be, for example, about 0.01 μm to 100 μm. The cross-sectional area of the first filter 5 is also arbitrary, but can be, for example, about 10 mm ² to 10000 mm ² . Preferably, the first filter 5 can be easily removed and washed as appropriate.

The head 2 is provided with a plurality of nozzles 2b in an aligned state. Here, the aligned state means that the nozzles 2b are arranged so that the directions in which ink is ejected are at least substantially the same, and in a plane perpendicular to the direction in which the nozzles 2b eject ink. are arranged at approximately equal intervals on one or more straight lines along one direction. The number of nozzles 2b in one head 2 is arbitrary, but can be, for example, about 1 to 1,000. The pitch of the nozzles 2b (the distance between the centers of adjacent nozzles 2b) is also arbitrary, but can be, for example, about 1 μm to 1000 μm. The resolution of the head 2 is also arbitrary, but can be, for example, about 50 dpi to 10000 dpi.

The ink ejection method of the head 2 is arbitrary, but for example, a piezo method, a thermal method, an electrostatic method, or the like can be used. The driving frequency of the head 2 is also arbitrary, but can be, for example, about 100 Hz to 200 kHz. The amount of ink ejected from one nozzle 2b at one time is also arbitrary, but can be, for example, about 0.001 pL to 100 pL. A plurality of heads 2 may be mounted on one inkjet printer 100 . If one ink jet printing apparatus 100 is desired to print with a plurality of types of ink, a plurality of heads 2 corresponding to the respective inks may be mounted.

A stage 7 that supports the printing material 60 is arranged so as to face the nozzles 2b of the head 2 along the ejection direction. The ink ejected from the nozzles 2 b adheres to the printing material 60 supported by the stage 7 , so that the ink is printed on the printing material 60 .

A driving mechanism (not shown) that drives at least one of the head 2 and the stage 7 so that the relative position between the nozzle 2b of the head 2 and the stage 7 (printing material 60) perpendicular to the ejection direction of the nozzle 2b is changed. ) is provided. In addition, when the relative position orthogonal to the ejection direction changes, the relative position along the ejection direction may also change. It is also preferable to provide a recognition function for recognizing the relative position between the nozzle 2b of the head 2 and the stage 7 (printing material 60).

In addition, the inkjet printing apparatus 100 is preferably provided with a head cleaning mechanism for cleaning the head 2, an alignment mechanism for aligning the print target position and the print target 60, a drying mechanism for drying the print target 60, and the like.

As described above, the inkjet printing apparatus 100 is characterized in that (a) the supply pipe 12 is provided with the first filter 5 and (b) the second head circulation pipe 9 is not provided with a filter. . Next, the reason for this will be explained.

In order to obtain excellent print quality, it is necessary that the ink does not contain coarse particles, that the ink does not contain air bubbles, and that there is no leakage of ink from the nozzles of the head.

In the present invention, by circulating the ink in the circulation path (the head circulation path and the tank circulation path), it is possible to suppress the sedimentation and agglomeration of the particle components to generate coarse particles in the ink. I am trying to remove the coarse particles that have been removed.

In the circulation path, the speed of circulating ink is important. If the ink circulates at a high speed, sedimentation and agglomeration of the particle components are less likely to occur and coarse particles are less likely to be generated, but air bubbles are more likely to enter the ink from the nozzles of the head. On the other hand, if the speed of the circulating ink is slow, it is possible to suppress the entry of air bubbles into the ink from the nozzles of the head, but the particle components tend to sediment or agglomerate to form coarse particles. Therefore, by adjusting the driving force (suction force, ejection force) of the pump, the speed of the ink circulating in the circulation path is controlled to suppress the generation of coarse particles due to sedimentation and agglomeration of the particle components. It is important to keep the speed at which the intrusion of air bubbles into is suppressed.

However, as a result of research by the present applicant, when a filter is provided in the path of the ink, depending on the position of the filter, the flow of the ink is affected, and the speed of the ink cannot be maintained. It has been found that there are cases where coarse particles are generated in the ink, air bubbles enter the ink, or the ink leaks from the nozzles of the head due to local changes in pressure.

Applicant conducted the following Experiment 1 to determine the proper position to place the filter. An inkjet printing apparatus 100 was used as the apparatus for Experiment 1. FIG. However, in Experiment 1, the supply pipe 12 may not be provided with the first filter 5 . In the inkjet printing apparatus 100 used in this experiment, the first flow path resistance, which is the flow path resistance from the discharge port 2c of the head 2 to the first suction port 3a of the first pump 3, was set to about 150 Pa, and the first tank The second flow path resistance, which is the flow path resistance from the first ink outlet 1e of the first pump 3 to the first suction port 3a of the first pump 3, was set to about 880Pa.

The flow path resistance can be appropriately set by selecting one or more of, for example, the inner diameter of the pipe, the length of the pipe, the roughness of the inner surface of the pipe, the material of the pipe, and the like. The flow path resistance can be changed by reducing or increasing the inner diameter of the pipe in part.

In Experiment 1, a filter was provided on both the supply pipe 12 and the second head circulation pipe 9 between the head 2 and the first connection point J1, or either one of them was provided with a filter. Either without a filter or not. Specifically, in the sample 1, filters were provided both in the supply pipe 12 and in the second head circulation pipe 9 between the head 2 and the first connection point J1. For Sample 2, a filter was provided between the head 2 of the second head circulation pipe 9 and the first connection point J1, and the supply pipe 12 was not provided with a filter. In Sample 3, a filter was provided in the supply pipe 12, and no filter was provided between the head 2 of the second head circulation pipe 9 and the first connection point J1. In Sample 4, no filter was provided between the supply pipe 12 and the second head circulation pipe 9 between the head 2 and the first connection point J1.

After adjusting the driving force (suction force, ejection force) of the first pump 3 to a size that does not cause sedimentation or agglomeration of particle components in the ink and that bubbles do not enter the ink from the head, , the presence or absence of ink leakage from the nozzles 2b of the head 2 was checked. The results are shown in Table 1.

As shown in Table 1, only the sample 3 in which the supply pipe 12 was provided with a filter and no filter was provided between the head 2 of the second head circulation pipe 9 and the first connection point J1 was the nozzle 2b of the head 2. Ink leakage did not occur in Samples 1, 2 and 4.

Based on the results of Experiment 1, the inkjet printing apparatus 100 (a) has the first filter 5 in the supply pipe 12 and (b) has no filter in the second head circulation pipe 9 . Therefore, in the ink jet printing apparatus 100, the ink circulating through the head circulation path (the first head circulation pipe 8 and the second head circulation pipe 9) does not cause sedimentation or aggregation of the particle component, and the ink from the nozzle 2b of the head 2 is It is possible to simultaneously satisfy the three requirements that air bubbles do not enter the nozzles 2b of the head 2 and ink does not leak from the nozzles 2b.

By driving the first pump 3, the ink jet printing apparatus 100 constantly supplies ink through the first pump 3, the first head circulation pipe 8, the head 2, and the second head circulation pipe 9, which are the head circulation paths. , and the first pump 3 in order, sedimentation and agglomeration of the particle components in the head circulation path are suppressed.

In the inkjet printing apparatus 100, in order to supplement the ink ejected from the nozzles 2b of the head 2, the ink is supplied from the first tank 1 to the head circulation path via the supply pipe 12, but the ink is stored in the first tank 1. Even if the applied ink contains coarse particles, they can be removed by the first filter 5. - 特許庁

In the inkjet printing apparatus 100, entry of air bubbles into the ink from the nozzles 2b of the head 2 and leakage of ink from the nozzles 2b of the head 2 are suppressed.

In the inkjet printing apparatus 100, the ink discharged from the discharge port 2c of the head 2 and the ink supplied from the supply pipe 12 are combined and sucked by the first suction port 3a of the first pump 3, and the first discharge port 3b is sucked. Since the ink is ejected from the head 2 and sent to the head 2 for printing, stable printing can be performed. That is, if the ink ejected from the first ejection port 3b of the first pump 3 and the ink supplied from the supply pipe 12 are sent together to the head 2 and printed without using such a method, , air bubbles tend to enter from the nozzles 2b of the head 2, and the printing becomes unstable.

(Modification 1 of First Embodiment: Inkjet Printing Apparatus 110)
FIG. 2 shows an inkjet printer 110 according to Modification 1 of the first embodiment.

The inkjet printing apparatus 110 has the second filter 6 arranged in the first head circulation pipe 8 of the inkjet printing apparatus 100 . The second filter 6 is arranged with the second upstream port 6a on the first pump 3 side and the second downstream port 6b on the head 2 side. As the second filter 6, the same filter as the first filter 5 was used.

In the inkjet printing apparatus 110, the ink circulating in the head circulation path (the first head circulation pipe 8 and the second head circulation pipe 9) contains coarse particles due to sedimentation or agglomeration of particle components such as pigments and metal particles. If so, it can be removed by the second filter 6 .

(Modified Example 2 of First Embodiment: Inkjet Printer 120)
FIG. 3 shows an inkjet printer 120 according to Modification 2 of the first embodiment. The inkjet printing device 120 is a modification of the inkjet printing device 110 according to Modification 1. FIG.

The inkjet printing apparatus 120 is provided with an air release flow path 13 extending vertically upward between the first pump 3 and the second filter 6 of the first head circulation pipe 8 of the inkjet printing apparatus 110. . The inkjet printing apparatus 120 can remove unnecessary air bubbles from the ink flowing through the first head circulation pipe 8 by the air vent channel 13 .

The upper surface of the ink contained in the air vent channel 13 is kept within a certain range by balancing the weight of the ink and the pressure with which the first pump 3 ejects the ink. Therefore, unnecessary air bubbles are released to the atmosphere from the tip of the air vent channel 13 without ink overflowing from the air vent channel 13 that is released to the atmosphere.

Although the material, dimensions, etc. of the air vent channel 13 are arbitrary, the length of the air vent channel 13 is preferably 10 mm or more. This is to prevent the ink from overflowing from the tip of the air vent channel 13 . In this modified example, the same material and inner diameter as the first head circulation pipe 8, the second head circulation pipe 9, and the supply pipe 12 are used for the air vent channel 13. FIG.

Since the ink jet printer 120 removes unnecessary air bubbles from the ink flowing through the first head circulation pipe 8 before the ink passes through the second filter 6 and the pressure is reduced, the efficiency of air bubble removal is high.

(Modified Example 3 of First Embodiment: Inkjet Printer 130)
FIG. 4 shows an inkjet printer 130 according to Modification 3 of the first embodiment. The inkjet printer 130 is also modified from the inkjet printer 110 according to Modification 1. FIG.

In the inkjet printing apparatus 130, an air release flow path 13 extending upward in the vertical direction is provided between the second filter 6 of the first head circulation pipe 8 of the inkjet printing apparatus 110 and the head 2. As shown in FIG. The inkjet printing apparatus 130 can remove unnecessary air bubbles from the ink flowing through the first head circulation pipe 8 by the air vent channel 13 .

Since the inkjet printer 130 removes unnecessary air bubbles just before the head 2 in the first head circulation pipe 8 , air bubbles can be reliably removed from the ink introduced into the inlet 2 a of the head 2 .

(Modification 4 of First Embodiment: Inkjet Printer 140)
FIG. 5 shows an inkjet printer 140 according to Modification 4 of the first embodiment. The inkjet printing device 140 further modifies the inkjet printing device 120 according to Modification 2. FIG.

The ink jet printer 140 provided the second ink supply port 1b in the first tank 1, and connected the tip of the air vent channel 13 to the second ink supply port 1b.

The ink jet printer 140 can return the overflowing ink to the first ink reservoir 1 d of the first tank 1 even if the ink overflows from the air vent channel 13 . Therefore, the ink jet printer 140 does not waste ink, and does not perform unnecessary work such as cleaning spilled ink stains.

[Second embodiment]
FIG. 6 shows an inkjet printing device 200 according to the second embodiment. However, FIG. 6 is an explanatory diagram of the inkjet printing apparatus 200 .

(c) the first filter 5 is provided in the supply pipe 12; setting the second flow resistance, which is the flow resistance, to be at least ten times as large as the first flow resistance, which is the flow resistance from the discharge port 2c of the head 2 to the first suction port 3a of the first pump 3; making it an important feature.

In this specification, the flow path resistance of the flow path provided with the filter refers to the flow path resistance including the filter.

In Experiment 1 described above, when filters were provided in both the supply pipe 12 and the second head circulation pipe 9 between the head 2 and the first connection point J1 (Sample 1), the nozzle 2b of the head 2 An ink leak has occurred. However, in Experiment 1, the second flow resistance, which is the flow resistance from the first ink outlet 1e of the first tank 1 to the first suction port 3a of the first pump 3, It was approximately 5.9 times the first flow resistance, which is the flow resistance up to the first suction port 3a of the No. 1 pump 3 .

As a result of trial and error, the applicant of the present application found that even when filters are provided in both the supply pipe 12 and between the head 2 and the first connection point J1 of the second head circulation pipe 9, the first The second flow path resistance, which is the flow path resistance from the first ink outlet 1e of the first tank 1 to the first suction port 3a of the first pump 3, is the first suction of the first pump 3 from the discharge port 2c of the head 2. It has been found that ink leakage from the nozzles 2b of the head 2 can be suppressed by making it 10 times or more the first flow path resistance, which is the flow path resistance to the port 3a.

Normally, the first flow path resistance, which is the flow path resistance from the discharge port 2c of the head 2 to the first suction port 3a of the first pump 3, is set to approximately 10Pa to 400Pa. On the other hand, the second flow path resistance, which is the flow path resistance from the first ink outlet 1e of the first tank 1 to the first suction port 3a of the first pump 3, is set to approximately 50Pa to 2000Pa. Within these ranges, if the second flow path resistance is set to 10 times or more of the first flow path resistance, the pressure between the supply pipe 12 and the head 2 of the second head circulation pipe 9 and the first connection point J1 can be reduced. Ink leakage from the nozzles 2b of the head 2 can be suppressed even when filters are provided in both of the above.

To confirm this finding, the following Experiment 2 was performed. For the apparatus of Experiment 2, the inkjet printing apparatus 100 of the first embodiment in which the first filter 5 is provided in the supply pipe 12 is used, and the head 2 of the second head circulation pipe 9 and the first connection point J1 are used. A filter was added between

In sample 11, the second flow path resistance was double the first flow path resistance. In sample 12, the second flow path resistance was eight times the first flow path resistance. In sample 13, the second flow path resistance was ten times the first flow path resistance. Then, the driving force (suction force, ejection force) of the first pump 3 is adjusted to a magnitude that does not cause sedimentation or agglomeration of particle components in the ink and that bubbles do not enter the ink from the head. The presence or absence of ink leakage from the nozzles 2b of the head 2 was checked for each sample. The results are shown in Table 2.

As shown in Table 2, only Sample 13, in which the second flow path resistance was set to 10 times the first flow path resistance, caused no ink leakage from the nozzle 2b of the head 2, while Samples 11 and 12 caused ink leakage. did.

Based on the results of Experiment 2, the inkjet printing apparatus 200 according to the second embodiment follows the basic configuration of the inkjet printing apparatus 100 according to the first embodiment, and (c) the supply pipe 12 has the first A filter 5 is provided, and (d) the second flow resistance, which is the flow resistance from the first ink outlet 1e of the first tank 1 to the first suction port 3a of the first pump 3, is measured by the discharge port 2c of the head 2. to the first suction port 3a of the first pump 3, which is 10 times or more of the first flow resistance. Therefore, in the ink jet printing apparatus 200 as well, the ink circulating through the head circulation (the first head circulation pipe 8 and the second head circulation pipe 9) does not undergo sedimentation or agglomeration of particle components. It is possible to simultaneously satisfy the three requirements that no bubbles enter and no ink leaks from the nozzles 2 b of the head 2 .

The inkjet printing apparatus 200 can be said to be an inkjet printing apparatus in which ink leakage from the nozzles 2b of the head 2 is reliably suppressed even when the second head circulation pipe 9 is not provided with a filter.

(Modification 1 of Second Embodiment: Inkjet Printing Apparatus 210)
FIG. 7 shows an inkjet printer 210 according to Modification 1 of the second embodiment.

The inkjet printer 210 has a third filter 14 added between the head 2 of the second head circulation pipe 9 and the first connection point J1. The third filter 14 is arranged with the third upstream port 14a on the head 2 side and the third downstream port 14b on the first connection point J1 side.

In the inkjet printing apparatus 210, the ink circulating in the head circulation path (the first head circulation pipe 8 and the second head circulation pipe 9) contains coarse particles due to sedimentation or agglomeration of particle components such as pigments and metal particles. If so, it can be removed by the third filter 14 .

[Third embodiment]
FIG. 8 shows an inkjet printing device 300 according to the third embodiment. However, FIG. 8 is an explanatory diagram of the inkjet printing device 300 .

The inkjet printing apparatus 300 is obtained by adding a tank circulation path to the inkjet printing apparatus 100 according to the first embodiment. Specifically, the starting point is the first ink outlet 1e of the first tank 1, the end point is the first ink supply port 1a newly provided in the first tank 1, and the first tank circulation A tank circulation path consisting of the pipe 10, the second pump 4, and the second tank circulation pipe 11 is added.

In the inkjet printing apparatus 100, one end of the supply pipe 12 is connected to the first ink outlet 1e of the first tank 1, but in the inkjet printing apparatus 300, instead of this, one end of the supply pipe 12 is connected to It is connected to the second connection point J2 provided on the first tank circulation pipe 10 .

The ink jet printing apparatus 300 has (e) the first filter 5 provided in the supply pipe 12, (f) no filter provided in the second head circulation pipe 9, and (g) the first tank circulation pipe. 10, an important feature is that no filter is provided at a position from the first ink outlet 1e of the first tank 1 to the second connection point J2.

The same pump as the first pump 3 was used for the second pump 4 . The second pump 4 is provided in the tank circulation path with the second suction port 4a on the first tank circulation pipe 10 side and the second discharge port 4b on the second tank circulation pipe 11 side.

The first tank circulation pipe 10 and the second tank circulation pipe 11 are made of the same material and have the same inner diameter as the first head circulation pipe 8, the second head circulation pipe 9, and the supply pipe 12.

By driving the second pump 4, the ink jet printer 300 constantly circulates the ink in the tank circulation path (the first tank circulation pipe 10 and the second tank circulation pipe 11). Sedimentation and agglomeration of particle components are suppressed.

In the inkjet printing apparatus 300, the reason why (f) no filter is provided in the second head circulation pipe 9 is to suppress ink leakage from the nozzles 2b of the head 2, as explained in Experiment 1 of the first embodiment. be.

Next, in the inkjet printing apparatus 300, (e) the first filter 5 is provided in the supply pipe 12, and (g) in the first tank circulation pipe 10, from the first ink outlet 1e of the first tank 1 to the first The reason why the filter is not provided at the position up to the second connection point J2 will be explained.

When the ink stored in the first tank 1 contains coarse particles generated by sedimentation or agglomeration of particle components, the ink flows through the head circulation path (first head circulation pipe 8, second head circulation pipe 9). must be removed by a filter before being supplied to the

However, as a result of research by the present applicant, when the tank circulation path (first tank circulation pipe 10, second tank circulation pipe 11) and the second pump 4 are provided in the inkjet printing apparatus, the installation position of the filter If not properly selected, the second pump 4 will affect the ink supplied to the head circulation path (the first head circulation pipe 8 and the second head circulation pipe 9). It was found that air bubbles entered the

Applicant conducted Experiment 3 below to determine the proper position to place the filter. An inkjet printing device 300 was used as the device for Experiment 3. FIG. However, in Experiment 3, the supply pipe 12 may not be provided with the first filter 5 . In the inkjet printing apparatus 300 used in this experiment, the third flow path resistance, which is the flow path resistance from the discharge port 2c of the head 2 to the second suction port 4a of the second pump 4, was set to about 880 Pa, and the first tank A fourth flow path resistance, which is a flow path resistance from the first ink outlet 1e of the second pump 4 to the second suction port 4a of the second pump 4, was set to about 110 Pa.

In Experiment 3, a filter was provided in both the supply pipe 12 and between the first ink outlet 1e of the first tank 1 and the second connection point J2 in the first tank circulation pipe 10. Either one had a filter or both had no filter. Specifically, the sample 21 is provided with filters both in the supply pipe 12 and in the first tank circulation pipe 10 between the first ink outlet 1e of the first tank 1 and the second connection point J2. Ta. In sample 22, a filter was provided between the first ink outlet 1e of the first tank 1 and the second connection point J2 in the first tank circulation pipe 10, and the supply pipe 12 was not provided with a filter. In sample 23, a filter was provided in the supply pipe 12, and no filter was provided between the first ink outlet 1e of the first tank 1 and the second connection point J2 in the first tank circulation pipe 10. In Sample 24, no filter was provided between the supply pipe 12 and the first tank circulation pipe 10 between the first ink outlet 1e of the first tank 1 and the second connection point J2.

First, the driving force (suction force, ejection force) of the first pump 3 was adjusted to such a magnitude that sedimentation and agglomeration of particle components would not occur in the head circulation path and air bubbles would not enter the ink from the head. Next, the driving force (suction force, discharge force) of the second pump 4 was adjusted to such a magnitude that sedimentation and agglomeration of the particle components would not occur in the tank circulation path. Then, for each sample, the presence or absence of air bubbles entering the ink from the nozzle 2b of the head 2 was checked. The results are shown in Table 3.

As shown in Table 3, a sample 23 in which a filter was provided in the supply pipe 12 and no filter was provided between the first ink outlet 1e of the first tank of the first tank circulation pipe 10 and the second connection point J2. However, air bubbles did not enter the ink from the nozzle 2b of the head 2, and air bubbles entered the ink in samples 21, 22, and 24. In the samples 21, 22, and 24, due to the influence of the second pump 4, the ink supplied to the head circulation path (the first head circulation pipe 8, the second head circulation pipe 9) is insufficient, and the nozzle 2b of the head 2 is It is thought that air bubbles entered the ink from the

Based on the results of Experiment 3, the inkjet printing apparatus 300 (e) provided the first filter 5 in the supply pipe 12, and A filter is not provided at a position from the outlet 1e to the second connection point J2. Therefore, the inkjet printing apparatus 300 does not run out of ink supplied to the head circulation path, and air bubbles are less likely to enter the ink from the nozzles 2 b of the head 2 .

Further, in the inkjet printing apparatus 300, the ink is always circulated through the head circulation path and the tank circulation path, so sedimentation and agglomeration of the particle components are suppressed in the head circulation path and the tank circulation path. Also, if the ink supplied from the head circulation path to the tank circulation path contains coarse particles, the first filter 5 removes the particles.

(Modification 1 of Third Embodiment: Inkjet Printing Apparatus 310)
FIG. 9 shows an inkjet printer 310 according to Modification 1 of the third embodiment.

The inkjet printer 310 has the second filter 6 arranged in the first head circulation pipe 8 .

Further, the inkjet printing apparatus 310 is provided with an air vent channel 13 between the first pump 3 and the second filter 6 of the first head circulation pipe 8 . Then, the tip of the air vent channel 13 was connected to the second ink supply port 1b of the first tank 1. As shown in FIG.

In the inkjet printing apparatus 310, the ink circulating through the head circulation path (the first head circulation pipe 8 and the second head circulation pipe 9) contains coarse particles due to sedimentation or agglomeration of particle components such as pigments and metal particles. If so, it can be removed by the second filter 6 .

Further, the ink jet printing apparatus 310 can remove unnecessary air bubbles from the ink flowing through the first head circulation pipe 8 by the air vent channel 13 . Even if the ink overflows from the air vent channel 13, the ink jet printing apparatus 310 can return the overflowed ink to the first ink reservoir 1d of the first tank, so that the ink is not wasted.

[Fourth embodiment]
FIG. 10 shows an inkjet printer 400 according to the fourth embodiment. However, FIG. 10 is an explanatory diagram of the inkjet printer 400 .

The inkjet printing apparatus 400 has (h) the provision of the first filter 5 in the supply pipe 12, and (i) the flow path resistance from the discharge port 2c of the head 2 to the second suction port 4a of the second pump 4. The third flow path resistance is 10 times or more the fourth flow path resistance, which is the flow path resistance from the first ink outlet 1e of the first tank 1 to the second suction port 4a of the second pump 4. making it an important feature.

In Experiment 3 described above, when filters were provided in both the supply pipe 12 and between the first ink outlet 1e of the first tank and the second connection point J2 in the first tank circulation pipe 10 (Sample 21 ), air bubbles entered the ink from the nozzle 2 b of the head 2 . However, in Experiment 3, the third flow path resistance, which is the flow path resistance from the discharge port 2c of the head 2 to the second suction port 4a of the second pump 4, It was approximately eight times the fourth flow resistance, which is the flow resistance up to the second suction port 4 a of the second pump 4 .

As a result of trial and error, the applicant of the present application provided a filter both between the first ink outlet 1e of the first tank and the second connection point J2 of the first tank circulation pipe 10 and the supply pipe 12. Even in the case of It was found that if the fourth flow resistance, which is the flow resistance to the second suction port 4a of the second pump 4, is set to 10 times or more, the intrusion of air bubbles into the ink from the nozzles 2b of the head 2 can be suppressed.

Normally, the third flow path resistance, which is the flow path resistance from the discharge port 2c of the head 2 to the second suction port 4a of the second pump 4, is set to approximately 50Pa to 2000Pa. On the other hand, the fourth flow path resistance, which is the flow path resistance from the first ink outlet 1e of the first tank 1 to the second suction port 4a of the second pump 4, is set to approximately 10Pa to 400Pa. Within these ranges, if the third flow path resistance is 10 times or more the fourth flow path resistance, the first ink outlet of the first tank 1 in the supply pipe 12 and the first tank circulation pipe 10 Even if a filter is provided both between 1e and the second connection point J2, it is possible to prevent air bubbles from entering the ink from the nozzles 2b of the head 2. FIG.

To confirm this finding, the following Experiment 4 was performed. For the apparatus of Experiment 4, the inkjet printing apparatus 300 of the third embodiment in which the first filter 5 is provided in the supply pipe 12 is used, and the first ink in the first tank 1 in the first tank circulation pipe 10 is used. A filter is additionally provided between the outlet 1e and the second connection point J2.

In sample 31, the third flow path resistance was double the fourth flow path resistance. In sample 32, the third flow path resistance was eight times the fourth flow path resistance. In sample 33, the third flow path resistance was ten times the fourth flow path resistance. Then, for each sample, the presence or absence of air bubbles entering the ink from the nozzle 2b of the head 2 was checked. The results are shown in Table 4.

As shown in Table 4, only Sample 33, in which the third flow resistance was set to 10 times the fourth flow resistance, did not allow air bubbles to enter the ink from the nozzles 2b of the head 2, whereas Samples 31 and 32 allowed air bubbles to enter. .

Based on the result of Experiment 4, the inkjet printing apparatus 400 according to the fourth embodiment follows the basic configuration of the inkjet printing apparatus 300 according to the third embodiment, and (h) the first supply pipe 12 A filter 5 is provided, and (i) the third flow resistance, which is the flow resistance from the discharge port 2c of the head 2 to the second suction port 4a of the second pump 4, is measured by the first ink outlet 1e of the first tank 1. to the second suction port 4a of the second pump 4, which is 10 times or more of the fourth flow resistance. Therefore, in the inkjet printing apparatus 400 as well, sedimentation and agglomeration of particle components in the head circulation path and the tank circulation path are suppressed, and air bubbles from the nozzles 2b of the head 2 are suppressed from entering the ink.

Also in the inkjet printing apparatus 400 , if the ink supplied from the head circulation path to the tank circulation path contains coarse particles, they are removed by the first filter 5 .

Note that even if the inkjet printing apparatus 400 does not provide a filter between the first tank 1 and the second connection point J2 of the first tank circulation pipe 10, air bubbles entering the ink from the nozzles 2b of the head 2 are prevented from entering the ink. can be said to be an inkjet printing apparatus in which is reliably suppressed.

(Modification 1 of Fourth Embodiment: Inkjet Printing Apparatus 410)
FIG. 11 shows an inkjet printer 410 according to Modification 1 of the fourth embodiment.

The inkjet printer 410 has a fourth filter 15 added between the first tank 1 of the first tank circulation pipe 10 and the second connection point J2. The fourth filter 15 is arranged with the fourth upstream port 15a on the first tank 1 side and the fourth downstream port 15b on the second connection point J2 side.

The inkjet printer 410 reduces the third flow path resistance, which is the flow path resistance from the discharge port 2c of the head 2 to the second suction port 4a of the second pump 4, from the first ink outlet 1e of the first tank 1 to the third flow path resistance. 2 pump 4 to the second suction port 4a or more, even if the fourth filter 15 is added, the entry of air bubbles into the ink from the nozzle 2b of the head 2 is suppressed. It is

In the inkjet printing apparatus 410, the ink circulating through the tank circulation path (the first tank circulation pipe 10 and the second tank circulation pipe 11) contains coarse particles due to sedimentation or agglomeration of particle components such as pigments and metal particles. If so, it can be removed by the fourth filter 15 .

(Modified example 2 of the fourth embodiment: inkjet printer 420)
FIG. 12 shows an inkjet printer 420 according to Modification 2 of the fourth embodiment. Inkjet printing device 420 is also a modification of inkjet printing device 400 .

The inkjet printing device 420 has the second filter 6 arranged in the first head circulation pipe 8 .

Further, the inkjet printing apparatus 420 is provided with an air vent channel 13 between the first pump 3 and the second filter 6 of the first head circulation pipe 8 .

In the inkjet printing apparatus 420, the ink circulating in the head circulation path (the first head circulation pipe 8 and the second head circulation pipe 9) contains coarse particles due to sedimentation or agglomeration of particle components such as pigments and metal particles. If so, it can be removed by the second filter 6 .

Further, the ink jet printing apparatus 420 can remove unnecessary air bubbles from the ink flowing through the first head circulation pipe 8 by the air vent channel 13 . Even if the ink overflows from the air vent channel 13, the ink jet printer 420 can return the overflowed ink to the first ink reservoir 1d of the first tank, so that the ink is not wasted.

The inkjet printing apparatuses according to the first to fourth embodiments and their modifications have been described above. However, the present invention is not limited to the contents described above, and various modifications can be made along the spirit of the invention.

For example, in the above-described embodiment, only the first tank 1 is provided in the inkjet printing apparatus, but the number of tanks is arbitrary. You may make it

Moreover, in the above embodiment, the minimum number of filters is shown, and filters may be additionally provided at other positions in the piping as long as they do not contradict the gist of the invention.

Also, a head cleaning mechanism may be added to the head 2 of the inkjet printing apparatus of each embodiment. As the head cleaning mechanism, for example, a nozzle opening wiping type, a head internal cleaning type, or the like can be adopted.

The nozzle opening wiping type head cleaning mechanism brings the wiping member into contact with the opening of the nozzle 2b of the head 2 and the vicinity thereof before, after, or between printing operations, and moves it relatively parallel to wipe off adhering matter. It is a cleaning mechanism that

The material of the portion of the wiping member that contacts the opening of the nozzle 2b of the head 2 and its vicinity may include at least one of cloth such as waste cloth, paper, resin, and rubber. At least the surface of the wiping member may be uneven, mesh-like, or spongy. The shape of the wiping member can be any shape that facilitates wiping, such as a planar shape, a blade shape, or a roller shape. A sheet-like wiping member may be wound around a roller or the like and wound up after use to prevent reattachment of contaminants from the wiping member to the opening of the nozzle 2b of the head 2. .

The head 2 is provided with a plurality of nozzles 2b in an aligned state, and the direction of wiping by the wiping member may be the orthogonal direction or the parallel direction. When there are a plurality of heads 2, they may be cleaned sequentially by one head cleaning mechanism, or may be provided with a plurality of head cleaning mechanisms. In addition, a plurality of wiping members may be provided so that a plurality of heads can be cleaned simultaneously by a single head cleaning mechanism, or a single wiping member may be provided with a plurality of protrusions, and each protrusion may be a different head. The head may be washed.

Prior to cleaning the head, cleaning liquid may be applied to the wiping member in advance. Alternatively, the cleaning liquid may be adhered to the nozzle openings of the head and the vicinity thereof by a method such as immersion or spraying before contact with the wiping member. Examples of the cleaning liquid include water, acidic or alkaline aqueous solutions, and organic solvents such as alcohol.

Instead of the wiping member, a suction mechanism may be arranged in contact with or separated from the opening of the nozzle 2b of the head 2 and in the vicinity thereof to suck and remove the adhering matter. When the wiping member is mesh-like or sponge-like, a suction mechanism may be placed in contact with or separated from the wiping member to suck the adhering matter and transfer it to the wiping member to remove it.

On the other hand, the internal head cleaning type head cleaning mechanism introduces cleaning liquid into the interior of the head 2 through at least one of the inlet 2a and the outlet 2c of the head 2 and through the nozzles 2b when the printing operation is not performed. By discharging, the deposits inside the head 2 are removed. The means for discharging the cleaning liquid inside the head 2 from the nozzles 2b may be the same as the means for ejecting the ink, or the cleaning liquid may be discharged by feeding the cleaning liquid into the head with a pump or the like and pressurizing it. Examples of the cleaning liquid include water, acidic or alkaline aqueous solutions, and organic solvents such as alcohol.

Both a nozzle opening wiping type head cleaning mechanism and a head internal cleaning type head cleaning mechanism may be added to the head 2 of the inkjet printing apparatus of each embodiment.

Further, a fixing mechanism for fixing the printing material 60 may be provided on the stage 7 of the inkjet printing apparatus of each embodiment. As a fixing method, for example, vacuum adsorption, mechanical holding, electrostatic adsorption, or the like can be adopted. Further, a heating mechanism for heating the printing material 60 may be provided on the stage 7 . The heating temperature can be, for example, 10.degree. C. to 100.degree. Also, a plurality of stages 7 may be provided in one inkjet printer.

Further, the inkjet printing apparatus of each embodiment may be provided with a driving mechanism for driving at least one of the stage 7 and the head 2 . The drive mechanism drives at least one of the stage 7 and the head 2 in one direction substantially perpendicular to the ejection direction of ink from the nozzles 2 b of the head 2 . The speed of relative movement between the head 2 and the stage 7 during scanning is, for example, about 1 mm/sec to 2000 mm/sec. Further, when the head 2 is driven by the drive mechanism, at least one of the tank (main tank, sub-tank), pump, filter, and piping may be driven integrally with the head 2 .

Further, the inkjet printing apparatus of each embodiment may be provided with a supply mechanism for supplying the printing material 60 to the stage 7 . The printed material 60 before printing is stored in a container such as a cassette, or is transported by the transport mechanism after being subjected to predetermined processing in the previous process. Before printing, the stage 7 moves to either a range driven by scanning or to a supply position set separately from the range driven by scanning and stops. The supply mechanism holds the printing material 60 by a vacuum suction holding function or a mechanical holding function, conveys the printing material 60 to the stage 7, and then releases the holding.

Further, the inkjet printing apparatus of each embodiment may be provided with a discharge mechanism for discharging the printing material from the stage 7 . The printed material 60 after printing needs to be stored in a container such as a cassette, or transferred to a transport mechanism in order to be subjected to predetermined processing in a later process. After printing, the stage 7 moves to either the range driven by scanning or to a discharge position set separately from the range driven by scanning and stops. The ejection mechanism holds the printing material 60 by a vacuum suction holding function or a mechanical holding function, and releases the holding after transporting the printing material 60 to a container or a transport mechanism.

Further, the inkjet printing apparatus of each embodiment may be provided with an alignment mechanism. Alignment mechanisms include, for example, lenses, cameras, and lighting. A lens with a magnification of, for example, 0.5 times to 10 times can be used. For the camera, for example, a CCD camera or a CMOS camera with 100,000 to 10,000,000 pixels can be used. For illumination, for example, LED illumination can be used.

The alignment mechanism recognizes the position of the workpiece by, for example, providing alignment marks on the material to be printed 60 in advance, illuminating the alignment marks, and taking an image with a camera. If the printing material 60 is printed a plurality of times or printed in another process in advance, part or all of the already formed print pattern may be used as the alignment mark. The alignment mechanism operates the drive mechanism so that the recognized position of the printing material 60 and the planned print position are brought closer.

Further, the inkjet printing apparatus of each embodiment may be provided with a drying mechanism, a degreasing mechanism, a synthesizing mechanism, and the like. The drying mechanism dries the ink adhered and printed on the substrate 60 to be printed. The degreasing mechanism reduces or removes the resin component by heating or the like when the ink adhered to and printed on the printing material 60 contains the resin component. The synthesizing mechanism synthesizes a desired material from the particles by heating or the like when the ink adhered to and printed on the printing substrate 60 contains particles of a precursor. Two or three of the drying mechanism, the degreasing mechanism, and the synthesizing mechanism may be combined into one mechanism.

As the drying, degreasing, and synthesizing methods, for example, one or more of hot air, heating of the workpiece, depressurization of the atmosphere, irradiation of visible light, ultraviolet light, infrared light, or laser light can be used.

The drying mechanism, the degreasing mechanism, and the synthesizing mechanism dry, degreasing, and synthesizing the ink after printing, for example, on the stage 7 on which printing has been performed. Alternatively, the printing material 60 is moved to a separately provided drying unit or the like, and the ink after printing is dried, degreased, and synthesized. When drying is performed by heating, for example, the maximum temperature is set to approximately 30° C. or higher and 150° C. or lower. When degreasing is performed by heating, for example, the maximum temperature is set to approximately 150° C. or higher and 800° C. or lower. When the synthesis is performed by heating, the maximum temperature is, for example, about 800° C. or higher and 1500° C. or lower.

The inkjet printing apparatuses according to the first to fourth embodiments of the present invention are as described in the section "Means for Solving the Problems".

In these inkjet printing apparatuses, the first head circulation pipe has a second upstream port and a second downstream port, and filters ink passing from the second upstream port to the second downstream port. It is also preferred to have two filters. In this case, the second filter can remove coarse particles from the ink circulating in the head circulation path.

Moreover, in these inkjet printing apparatuses, it is also preferable to provide an air vent flow path, one end of which is connected to the first head circulation pipe. In this case, air bubbles contained in the ink circulating in the head circulation path can be removed by the air vent channel.

Further, in these inkjet printing apparatuses, the first head circulation pipe has a second upstream port and a second downstream port, and filters ink passing from the second upstream port to the second downstream port. , a second filter, and an air vent passage for removing air bubbles contained in ink passing through the first head circulation pipe, one end of which is connected to the first head circulation pipe, and which is used for the first head circulation. In the piping, it is also preferable that the air vent channel is connected at a position close to the first pump and the second filter is located at a position close to the head. In this case, since unnecessary air bubbles are removed from the ink flowing through the first head circulation pipe before the pressure drops after passing through the second filter, the efficiency of removing air bubbles increases.

Alternatively, in these inkjet printing apparatuses, the first head circulation pipe has a second upstream port and a second downstream port, and filters ink passing from the second upstream port to the second downstream port. , a second filter, and an air vent passage for removing air bubbles contained in ink passing through the first head circulation pipe, one end of which is connected to the first head circulation pipe, and which is used for the first head circulation. In the piping, it is also preferable that the second filter is located near the first pump and the air vent channel is connected to the position near the head. In this case, since unnecessary air bubbles are removed immediately before the head in the first head circulation pipe, air bubbles can be reliably removed from the ink introduced into the inlet of the head.

The other end of the air vent channel may be open to the atmosphere, or may be connected to the first tank. In the former case, the configuration is simple. In the latter case, even if the ink overflows from the air vent channel, the overflowed ink can be returned to the first ink reservoir 1d of the first tank 1, so that the ink is not wasted or the device is dirty. do not have.

1 First tank 1a First ink supply port 1b Second ink supply port 1c Third ink supply port 1e First ink outlet 1f Lid 2 Head 2a Introduction port 2b Nozzle 2c Discharge port 3 First pump 3a First suction port 3b First discharge port 4 Second pump 4a Second suction port 4b Second discharge port 5 First filter 5a First upstream port 5b First downstream port 6 Second filter 6a Second upstream port 6b Second downstream port 7 Stage 8 First head circulation pipe 9 Second head circulation pipe 10 First tank circulation pipe 11・Second tank circulation pipe 12 Supply pipe 13 Air vent channel 14 Third filter 14a Third upstream port 14b Third downstream port 15 Third 4 Filter 15a Fourth upstream port 15b Fourth downstream port

Claims (9)

a first tank having a first ink reservoir and a first ink outlet;
a head having an inlet for introducing ink, a nozzle for ejecting ink, and an outlet for ejecting ink not ejected from the nozzle;
a first pump having a first suction port for sucking ink and a first ejection port for ejecting ink;
a first head circulation pipe that connects the first outlet of the first pump and the inlet of the head;
a second head circulation pipe that connects the discharge port of the head and the first suction port of the first pump;
a supply pipe connecting at least one of the first ink outlet of the first tank, the first suction port of the first pump, and an arbitrary position of the second head circulation pipe; ,
a first filter having a first upstream port and a first downstream port and disposed in the supply pipe for filtering ink passing from the first upstream port to the first downstream port;
A flow path resistance from the discharge port of the head to the first suction port of the first pump is defined as a first flow path resistance,
When the flow path resistance from the first ink outlet of the first tank to the first suction port of the first pump is defined as a second flow path resistance,
The second flow path resistance is 10 times or more the first flow path resistance,
Inkjet printing device. a first tank having a first ink supply port, a first ink reservoir, and a first ink outlet;
a head having an inlet for introducing ink, a nozzle for ejecting ink, and an outlet for ejecting ink not ejected from the nozzle;
a first pump having a first suction port for sucking ink and a first ejection port for ejecting ink;
a first head circulation pipe that connects the first outlet of the first pump and the inlet of the head;
a second head circulation pipe that connects the discharge port of the head and the first suction port of the first pump;
a second pump having a second suction port for sucking ink and a second ejection port for ejecting ink;
a first tank circulation pipe that connects the first ink outlet of the first tank and the second suction port of the second pump;
a second tank circulation pipe that connects the second discharge port of the second pump and the first ink supply port of the first tank;
a supply pipe connecting an arbitrary position of the first tank circulation pipe and at least one of the first suction port of the first pump and an arbitrary position of the second head circulation pipe;
a first filter having a first upstream port and a first downstream port and disposed in the supply pipe for filtering ink passing from the first upstream port to the first downstream port;
A filter is not arranged in the second head circulation pipe,
In the first tank circulation pipe, no filter is arranged at a position from the first ink outlet of the first tank to the portion to which the supply pipe is connected.
Inkjet printing device. a first tank having a first ink supply port, a first ink reservoir, and a first ink outlet;
a head having an inlet for introducing ink, a nozzle for ejecting ink, and an outlet for ejecting ink not ejected from the nozzle;
a first pump having a first suction port for sucking ink and a first ejection port for ejecting ink;
a first head circulation pipe that connects the first outlet of the first pump and the inlet of the head;
a second head circulation pipe that connects the discharge port of the head and the first suction port of the first pump;
a second pump having a second suction port for sucking ink and a second ejection port for ejecting ink;
a first tank circulation pipe that connects the first ink outlet of the first tank and the second suction port of the second pump;
a second tank circulation pipe that connects the second discharge port of the second pump and the first ink supply port of the first tank;
a supply pipe connecting an arbitrary position of the first tank circulation pipe and at least one of the first suction port of the first pump and an arbitrary position of the second head circulation pipe;
a first filter having a first upstream port and a first downstream port and disposed in the supply pipe for filtering ink passing from the first upstream port to the first downstream port;
A flow path resistance from the discharge port of the head to the second suction port of the second pump is defined as a third flow resistance,
When the flow path resistance from the first ink outlet of the first tank to the second suction port of the second pump is defined as a fourth flow path resistance,
The third flow path resistance is 10 times or more the fourth flow path resistance,
Inkjet printing device. a second filter having a second upstream port and a second downstream port and arranged in the first head circulation pipe for filtering ink passing from the second upstream port to the second downstream port; Ta,
An inkjet printing apparatus according to any one of claims 1 to 3 . An air vent passage for removing air bubbles contained in ink passing through the first head circulation pipe, one end of which is connected to the first head circulation pipe,
An inkjet printing apparatus according to any one of claims 1 to 4 . a second filter having a second upstream port and a second downstream port, and arranged in the first head circulation pipe for filtering ink passing from the second upstream port to the second downstream port;
an air vent channel, one end of which is connected to the first head circulation pipe, for removing air bubbles contained in the ink passing through the first head circulation pipe;
In the first head circulation pipe,
The air vent channel is connected to a position close to the first pump,
The second filter is located near the head,
An inkjet printing apparatus according to any one of claims 1 to 3 . a second filter having a second upstream port and a second downstream port, and arranged in the first head circulation pipe for filtering ink passing from the second upstream port to the second downstream port;
an air vent channel, one end of which is connected to the first head circulation pipe, for removing air bubbles contained in the ink passing through the first head circulation pipe;
In the first head circulation pipe,
The second filter is located near the first pump,
The air vent channel is connected to a position close to the head,
An inkjet printing apparatus according to any one of claims 1 to 3 . The other end of the air vent channel is open to the atmosphere,
An inkjet printing apparatus according to any one of claims 5 to 7 . The other end of the air vent channel is connected to the first tank,
An inkjet printing apparatus according to any one of claims 5 to 7 .

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