JP2021154697A - Ink circulation device - Google Patents

Abstract

To surely uniformize temperatures and flow volumes of ink to be supplied to a plurality of ink circulation type heads, when supplying the ink through one ink circulation circuit to the plurality of ink circulation type heads.SOLUTION: In one ink circulation device, an IN manifold 111 and an OUT manifold are provided respectively at IN sides and OUT sides of heads HD1-HD5, and five flow paths leading from the IN manifold 111 through each of the heads HD1-HD5 to the OUT manifold 113 are provided. The five flow paths are configured in such a manner that lengths and resistances of piping thereof are identical to each other. In the IN manifold 111, ink is adjusted to a desired temperature by a temperature regulator TR13 including a heater HE13, and in individual blocks 121, 123, 125, 127 and 129 at the IN sides, temperatures of ink are adjusted to be uniformized by temperature regulators Tri including heaters HEi provided in the blocks respectively.SELECTED DRAWING: Figure 2

Description

The present invention relates to an ink circulation device for supplying ink to a plurality of ink circulation heads that eject relatively highly viscous ink such as solder resist ink.

A solder resist pattern is formed on the printed circuit board in order to cover the surface thereof and protect the circuit pattern. An inkjet device is known as a solder resist pattern forming device that ejects solder resist ink from a plurality of inkjet heads onto a printed circuit board in order to form the solder resist pattern. Such an inkjet device may include an ink circulation device that supplies solder resist ink to a plurality of inkjet heads. The solder resist ink used here has thermosetting and UV curability and has a relatively high viscosity. Therefore, in consideration of this point, the ink circulation device is configured so that the flow rate of the ink supplied to each of the plurality of inkjet heads is made uniform, and the ink is supplied to the plurality of inkjet heads. It has a heater for heating the solder resist ink to be used.

In relation to the ink circulation device disclosed in the present application, Patent Document 1 (Japanese Unexamined Patent Publication No. 2019-1000) describes a liquid circulation device that supplies a liquid to be discharged from a plurality of through-flow type heads. (Paragraphs [0036] to [0048], FIG. 5). This liquid circulation device has a circulation path from the pressurized sub-tank 220 to the pressurized sub-tank 220 via the first manifold 230, the plurality of heads 100, the second manifold 240, and the depressurized sub-tank 210. In this circulation path, a solenoid valve 232 is provided in the supply path 231 from the first manifold 230 to each head 100, and a solenoid valve 242 is also provided in the discharge path 241 from each head 100 to the second manifold. Has been done.

Further, Patent Document 2 (Japanese Unexamined Patent Publication No. 2009-233589) describes an ink supply device that supplies and circulates ink to a plurality of ink circulation type heads (claim 1, paragraphs [0016] to [0018]. ]). This ink supply device includes a supply manifold section including an ink supply section, a circulation pump section 4, a supply manifold 18 and the like, a recovery manifold section including a recovery manifold 17 and the like, and an ink ejection section 5, and appropriately adjusts the ink temperature in the head. A temperature controller 27 is provided between the supply manifold and the recovery manifold in order to maintain the temperature.

JP-A-2019-1000 JP-A-2009-233589

In an inkjet device that ejects solder resist ink or UV ink, when ink is supplied to a plurality of inkjet heads by one ink circulation device (one ink circulation circuit), the viscosity of the ink is relatively high, so that the temperature is 45 ° C. Ink is circulated at the above high temperature. For this reason, a configuration for reducing variations in the temperature and flow rate of the ink supplied to each of the plurality of inkjet heads is required.

On the other hand, in the liquid circulation device described in Patent Document 1, the liquid circulation device is supplied from the first manifold to the plurality of heads 100 via the plurality of supply paths 231 and from the plurality of heads 100 via the plurality of discharge paths 241. By discharging the ink, the flow rates of the inks supplied to the plurality of heads 100 are made uniform. However, Patent Document 1 does not describe any configuration for adjusting the temperature of the ink supplied to the plurality of heads 100.

In the ink supply device described in Patent Document 2, a temperature controller 27 is provided between the supply manifold and the recovery manifold in order to keep the ink temperature in the head at an appropriate temperature. However, there is a possibility that the ink temperature varies in the process of supplying ink from the supply manifold to the plurality of ink circulation type heads, and the ink temperature in the plurality of ink circulation type heads cannot be made uniform.

Therefore, when one ink circulation circuit is used to supply ink to a plurality of ink circulation heads that eject relatively high-viscosity ink such as solder resist ink, the temperature of the ink supplied to the plurality of ink circulation heads. And it is desired to ensure uniform flow rate.

The first aspect of the present invention is an ink circulation device that circulates ink in one circulation circuit that passes through a plurality of ink circulation type inkjet heads and supplies ink to the plurality of inkjet heads.
In the circulation circuit, the supply side manifold and the discharge side manifold arranged on the upstream side and the downstream side of the plurality of inkjet heads, respectively,
A plurality of supply-side branch paths for forming a part of the circulation circuit and supplying ink in the supply-side manifold to the plurality of inkjet heads, respectively.
A plurality of discharge side branch paths for forming a part of the circulation circuit and discharging ink in the plurality of inkjet heads to the discharge side manifold, respectively.
A common temperature controller that includes a heater that heats the ink in the supply side manifold and regulates the temperature of the ink.
A plurality of individual temperature controllers each including a heater for heating ink supplied to each of the plurality of inkjet heads via the plurality of supply side branch paths and adjusting the temperature of the ink at the same target temperature. Be prepared.

The second aspect of the present invention is the first aspect of the present invention.
The plurality of branch paths from the supply-side manifold to the discharge-side manifold via the plurality of supply-side branch paths and the plurality of discharge-side branch paths are configured so that the pipe length and the piping resistance are the same. Has been done.

The third aspect of the present invention is the second aspect of the present invention.
A plurality of individual valves for opening and closing each of the plurality of branch paths are further provided.

The fourth aspect of the present invention is the third aspect of the present invention.
The plurality of individual valves are configured so that the flow rate can be adjusted.

The fifth aspect of the present invention is the second aspect of the present invention.
A plurality of supply-side individual valves that open and close the plurality of supply-side branch paths, respectively.
A plurality of discharge-side individual valves for opening and closing the plurality of discharge-side branch paths are further provided.

The sixth aspect of the present invention is the fifth aspect of the present invention.
Bypass flow path from the supply side manifold to the discharge side manifold,
A bypass valve for opening and closing the bypass flow path is further provided.

The seventh aspect of the present invention is the sixth aspect of the present invention.
A supply tank for storing ink to be supplied to the plurality of inkjet heads via the supply side manifold, and a supply tank.
A circulation tank that stores ink discharged from a plurality of inkjet heads via the discharge side manifold, and
A flow path for discharging ink from the discharge side manifold to the circulation tank, and
A flow path for sending ink from the circulation tank to the supply tank,
A flow path for supplying ink from the supply tank to the supply side manifold, and
A pressure adjusting device that sets the air pressure in the supply tank to a positive pressure,
A decompression adjustment device that sets the air pressure in the circulation tank to a negative pressure,
The plurality of supply-side individual valves, the plurality of discharge-side individual valves, the bypass valve, the pressure adjusting device, and a control unit for controlling the depressurizing adjusting device are further provided.
The control unit
When the ink circulation device is activated,
The plurality of supply-side individual valves and the plurality of discharge-side individual valves so that the plurality of supply-side individual valves and the plurality of discharge-side individual valves are closed and the bypass valves are opened in a predetermined standby period. Control the valve and the bypass valve,
In the standby period, the difference between the positive pressure set as the pressure of the supply tank and the atmospheric pressure is the steady positive pressure set as the pressure of the supply tank in the steady operation state of the ink circulation device. The difference between the negative pressure set as the pressure of the circulation tank and the atmospheric pressure, which is larger than the difference from the atmospheric pressure, is the negative pressure set as the pressure of the circulation tank in the steady operation state of the ink circulation device. The pressurization adjustment device and the decompression adjustment device are controlled so as to be larger than the difference between the steady negative pressure and the atmospheric pressure.
After the waiting period has passed,
The plurality of supply-side individual valves, the plurality of discharge-side individual valves, and the said Control the bypass valve,
The pressurization adjustment device and the decompression adjustment device are controlled so that the air pressure in the supply tank becomes the steady positive pressure and the air pressure in the circulation tank becomes the steady negative pressure.

According to the first aspect of the present invention, in a configuration in which ink is supplied to a plurality of inkjet heads by one circulation circuit, not only the ink in the supply side manifold is heated to adjust the temperature of the ink, but also the temperature of the ink is adjusted. The ink supplied from the supply-side manifold to the plurality of inkjet heads via the plurality of supply-side branch paths is heated, and the temperature of the ink is adjusted to the same target temperature. Thereby, the ink temperature in the plurality of inkjet heads to which the ink is supplied by one ink circulation circuit can be surely made uniform.

According to the second aspect of the present invention, since the plurality of branch paths from the supply side manifold to the discharge side manifold are configured to have the same pipe length and pipe resistance, the plurality of branch paths have the same length and resistance. The flow rate of the ink is made uniform, and the variation in the amount of ink supplied to the plurality of inkjet heads is suppressed.

According to the third aspect of the present invention, a plurality of branch paths from the supply side manifold to the discharge side manifold can be opened and closed by a plurality of individual valves.

According to the fourth aspect of the present invention, the flow rate of ink in each of the plurality of branch paths can be adjusted by a plurality of individual valves provided in the plurality of branch paths from the supply side manifold to the discharge side manifold. Therefore, in combination with the fact that the pipe lengths and pipe resistances of the plurality of branch paths are configured to be the same, it is possible to ensure uniform ink flow rates in the plurality of branch paths. can.

According to the fifth aspect of the present invention, a plurality of supply-side individual valves can be used to open and close a plurality of supply-side branch paths, and a plurality of discharge-side individual valves can be used to open and close a plurality of discharge-side branch paths.

According to the sixth aspect of the present invention, by opening the bypass valve, the ink supplied to the supply side manifold can be sent to the discharge side manifold via the bypass flow path without being supplied to the inkjet head side.

According to the seventh aspect of the present invention, the plurality of supply-side individual valves and the plurality of discharge-side individual valves are closed and the bypass valve is open during the standby period at the time of starting the ink circulation device. .. In addition, the difference between the positive pressure and the atmospheric pressure, which is the pressure of the supply tank, is made larger than the difference between the steady positive pressure and the atmospheric pressure of the supply tank, and the difference between the negative pressure and the atmospheric pressure, which is the pressure of the circulation tank. Is larger than the difference between the steady negative pressure and the atmospheric pressure of the circulation tank. By changing the difference between the negative pressure of the supply tank and the positive pressure of the circulation tank to be large, the flow rate of ink becomes larger than that during steady circulation. During the standby period at startup, the mixed air bubbles are discharged to the outside of the tank in a shorter time than before in a state where the air bubbles mixed in while the ink circulation device is stopped are prevented from flowing to the inkjet head side. , The temperature rise of the ink and the piping portion constituting the flow path is accelerated, and the time required to reach the steady ink temperature is shortened as compared with the conventional case.

It is a perspective view which shows the whole structure of the solder resist inkjet apparatus provided with the ink circulation apparatus which concerns on one Embodiment of this invention. It is a figure which shows the flow path structure in the ink circulation apparatus which concerns on the said embodiment. It is a figure for demonstrating the tank pressure adjustment in the ink circulation apparatus which concerns on the said embodiment. It is a block diagram which shows the hardware composition of the control part in the ink circulation apparatus which concerns on the said embodiment. It is a flowchart which shows the control process for controlling the flow and temperature of ink in the ink circulation apparatus which concerns on the said embodiment. It is a figure which shows the flow of the ink in the ink circulation system in the period from the execution of the start-up sequence to the start of the steady temperature control sequence in the above embodiment. It is a figure which shows the flow of the ink in the steady operation state of the ink circulation system in the said embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<1. Overall configuration>
FIG. 1 is a perspective view showing an overall configuration of a solder resist inkjet device including an ink circulation device according to an embodiment of the present invention. In the following, as shown in FIG. 1, it is assumed that an XYZ Cartesian coordinate system is defined in which two horizontal directions orthogonal to each other are the X-axis direction and the Y-axis direction, and the upward direction in the vertical direction is the Z-axis direction. This solder resist inkjet device includes a base 2 and a support structure 6 fixed on the base 2, a Y-axis direction moving mechanism 4 on the base 2, and an X-axis direction moving mechanism 3 on the side surface of the support structure 6. However, each is provided. The X-axis direction moving mechanism 3 includes a linear motor or the like (not shown) that moves the carriage 30 along the guide rail 41. The Y-axis direction moving mechanism 4 includes two guide rails 21 and 21 extending in the Y-axis direction, and these guide rails 21 and 21 are guided by them to move the table 10 in the Y-axis direction. Is installed. The Y-axis direction moving mechanism 4 includes a linear motor or the like (not shown) that moves the table 10 along the guide rail 21.

As described above, the inkjet moving body 30 is attached to the guide rails 41 and 41 via the elevating mechanism 5 so as to be movable in the X-axis direction, and the elevating mechanism 5 functions as a Z-axis direction moving mechanism. Therefore, the inkjet moving body 30 is configured to be movable not only in the X-axis direction but also in the Z-axis direction. The inkjet mobile body 30 includes a head portion 31 that ejects solder resist ink, and a circulation mechanism main body 33 for supplying the solder resist ink to the head portion 31.

The table 10 is a member for mounting a printed circuit board on which a solder resist pattern should be formed by ejecting solder resist ink from the head portion 31, and is a mechanism for fixing the mounted printed circuit board to the table (non-standard). (Fig.) Is provided.

Further, this solder resist inkjet device includes a control unit 50, and the control unit 50 controls the X-axis direction moving mechanism 3, the Y-axis direction moving mechanism 4, and the elevating mechanism 5, so that the head portion in the inkjet moving body 30 The relative positional relationship between the 31 and the printed circuit board placed on the upper surface of the table 10 can be arbitrarily changed within a predetermined range. As will be described later, this control unit 50 is also used to control the flow and temperature of the solder resist ink in the ink circulation device according to the present embodiment, and can also be used as a control unit that is a component of the ink circulation device. Function.

<2. Ink circulation device configuration>
Next, the ink circulation device according to the present embodiment will be described. This ink circulation device corresponds to the head portion 31 and the circulation mechanism main body portion 33 of the inkjet moving body 30 shown in FIG. 1 and constitutes a circulation flow path of the solder resist ink (hereinafter, “ink circulation system””. Alternatively, it includes an "ink circulation circuit") and a control unit 50 for controlling the flow and temperature of solder resist ink (hereinafter, also simply referred to as "ink") in this ink circulation system.

FIG. 2 is a diagram showing a configuration of an ink circulation system according to the present embodiment. As shown in FIG. 2, the ink circulation system in the present embodiment includes a circulation BOX ink circulation portion, a circulation carriage piping portion, and a head portion. Of these, the head portion is included in the head portion 31 shown in FIG. 1, and the circulation BOX ink circulation portion and the circulation carriage piping portion are included in the circulation mechanism main body 33 shown in FIG.

As shown in FIG. 2, the circulation BOX ink circulation unit includes a replenishment tank 101, a circulation tank 102, a supply tank 103, first and second common path solenoid valves SV11 and SV12, and first and second liquid feeds. It includes pumps EP1 and EP2, a filter FL for removing dust, and several level sensors (LV) for detecting the arrival of the upper and lower limits of the ink amount in each of the tanks 101 to 103. .. The ink supplied to the ink circulation device from the outside via the flow path 200 is first stored in the replenishment tank 101. A flow path 211 is provided between the replenishment tank 101 and the circulation tank 102, and the inside of the replenishment tank 101 is provided by the first liquid feeding pump EP1 provided in this flow path (hereinafter referred to as “first common flow path”) 211. Ink is sent to the circulation tank 102 via the first common road solenoid valve SV11. A flow path 212 is provided between the circulation tank 102 and the supply tank 103, and the ink in the circulation tank 102 is provided by the second liquid feed pump EP2 provided in this flow path (hereinafter referred to as “second common flow path”) 212. Is sent to the supply tank 103 via the second common road solenoid valve SV12 and the filter FL. The replenishment tank 101, the circulation tank 102, and the supply tank 103 are arranged at the same height (the same position in the vertical direction), and the circulation tanks are arranged so that the ink flows appropriately in the ink circulation system shown in FIG. The air pressure in the circulation tank 102 is adjusted to a negative pressure Pn and the air pressure in the circulation tank 102 is adjusted to a positive pressure Pp (details will be described later). The temperature controllers TR12, TR13, TR1 to TR9 for adjusting the ink temperature of each heating unit in the present embodiment include heaters HE12, HE13, HE1 to 9 and a temperature sensor thermostat, and are set by the control unit 50. Each heater is controlled so as to have a temperature.

As shown in FIG. 2, the circulation carriage piping portion includes a temperature controller including an IN side common manifold 111 as a supply side manifold, an OUT side common manifold 112 as a discharge side manifold, and a heating pipe heater HE12 (hereinafter, “heating”). TR12 (referred to as "tube temperature controller"), IN manifold liquid temperature sensor TS6 that detects the temperature of ink in the IN side common manifold 111, and first to tenth individual solenoid valves SV1 to SV10 as head individual valves. The first to tenth couplers CV1 to CV10 are included. The first to tenth individual solenoid valves SV1 to SV10 may be valves capable of continuously adjusting the flow rate of ink flowing through the corresponding flow paths. Further, the circulation carriage piping unit includes 10 head individual blocks including a first individual block 121, a second individual block 122, ..., And a tenth individual block 130. The head portion includes five inkjet heads (hereinafter, also simply referred to as “heads”) including a first head HD1, a second head HD2, ..., And a fifth head HD5. The IN side common manifold 111 includes a temperature controller (hereinafter referred to as “IN side common manifold temperature controller”) TR13 including an IN side common manifold heater HE13. The individual blocks on the IN side, that is, the first, third, fifth, seventh, and ninth individual blocks 121, 123, 125, 127, and 129 are head individual blocks for ink supply, and head individual block heaters HE1 and HE3. , HE5, HE7, HE9, respectively (hereinafter referred to as "head individual block temperature controller") TR1, TR3, TR5, TR7, TR9, respectively. Further, the head thermistors TS1 to TS5 are received by the heads HD1 to HD5. The head thermistors TS1 to TS5 are head thermistor temperatures TSt1 to TSt5 corresponding to the temperatures of the corresponding heads HD1, HD2, HD3, HD4, HD5 (approximately equal to the liquid temperature of the ink in the heads HD1, HD2, HD3, HD4, HD5). Is output.
Both the IN side common manifold 111 and the OUT side common manifold 112 have an ink buffer function.

As shown in FIG. 2, in this ink circulation system, a flow path 213 for ink supply from the supply tank 103 to the IN side common manifold (hereinafter, also referred to as “IN manifold”) 111 is provided, and this flow path (also referred to as “IN manifold”) 111 is provided. A heating tube heater HE12 is provided in 213 (hereinafter referred to as "third common flow path"). The third common flow path 213 is an IN manifold 111, and is branched into five ink supply flow paths including a first individual flow path 201, a second individual flow path 202, ..., And a fifth individual flow path 205. The first to fifth individual flow paths 201 to 205 as these supply-side branch paths are the first individual block 121, the third individual block 123, ..., The ninth individual block, which are five head individual blocks for supplying ink. 129, respectively. Further, the first to fifth individual path solenoid valves SV1 to SV5 are provided in each of the first to fifth individual flow paths 201 to 205, and the first to fifth couplers CV1 to CV5 are provided, respectively. .. The first to fifth individual flow paths 201 to 205 are branched into two flow paths at the first, third, fifth, seventh, and ninth individual blocks 121, 123, 125, 127, and 129, respectively, and the first to fifth individual flow paths are divided into two flow paths. It is connected to the supply ports of the first to fifth heads HD1 to HD5, respectively. Each head HDi (i = 1 to 5) has two supply ports for receiving ink and two discharge ports for discharging ink.

Each head HDi (i = 1 to 5) is an ink circulation type inkjet head, and among the inks supplied from the two supply ports, the ink not ejected from the nozzle of the head HDi passes through the corresponding nozzle. It is configured to be discharged from the two discharge ports.

At the outlets of the first to fifth heads HD1 to HD5, there are two flow paths leading to the second, fourth, sixth, eighth, and tenth individual blocks 122, 124, 126, 128, 130, respectively. It is connected. As a result, the ink discharged from the first to fifth heads HD1 to HD5 is discharged from the second, fourth, sixth, eighth, and tenth individual blocks 122, 124, 126 via two flow paths, respectively. , 128, 130, respectively, and each of these second, fourth, sixth, eighth, and tenth individual blocks 122, 124, 126, 128, 130 has one flow path for ink ejection. Is connected. That is, in these second, fourth, sixth, eighth, and tenth individual blocks 122, 124, 126, 128, 130, the sixth individual flow path 206 and the seventh individual flow path 206 and the seventh individual flow path are used as the flow paths for ink ejection. The flow paths 207, ..., And the tenth individual flow paths 210 are connected to each other, and the sixth to tenth individual flow paths 206 to 210 as the discharge side branch paths are referred to as OUT side common manifolds (hereinafter, also referred to as "OUT manifolds"). It leads to 112. The sixth to tenth individual flow paths 206 to 210 are provided with the sixth to tenth couplers CV6 to CV10, respectively, and the sixth to tenth individual path solenoid valves SV6 to SV10 are provided, respectively.

A fourth common flow path 214 for discharging ink is provided between the OUT manifold 112 and the circulation tank 102, and the common flow path 214 is discharged via the sixth to tenth individual flow paths. It is used to send ink to the circulation tank 102.

Further, in this ink circulation system, a bypass flow path 215 from the IN manifold 111 to the OUT manifold is provided, and the bypass solenoid valve SV13 is provided in the bypass flow path 215. This bypass solenoid valve (hereinafter, also referred to as “IN-OUT common manifold valve”) SV13 is opened in the start-up temperature control sequence described later, but is closed in the subsequent steady temperature control sequence (step S102 in FIG. 5 described later). See S122).

In the ink circulation system configured as described above, the ink is supplied to the first to fifth heads HD1 to HD5 during steady operation (in the steady operation state after the start-up temperature control sequence and the steady temperature control sequence described later are executed). In order to equalize the amount of ink to be produced, the IN manifold 111 is passed through the first to fifth individual flow paths 201 to 205, the first to fifth heads HD1 to HD5, and the sixth to tenth individual flow paths. The five flow paths leading to the OUT manifold 112 are configured so that their pipe lengths and pipe resistances are the same as each other. In this configuration, the pipe lengths and pipe resistances of the first to fifth individual flow paths 201 to 205 on the supply side are made the same as each other, and the sixth to tenth individual flow paths 206 to 210 on the discharge side are made the same. It is preferable that the length and resistance of the pipes are the same as each other. Further, the first to fifth individual path solenoid valves SV1 provided in the first individual flow path 201, the second individual flow path 202, ..., And the fifth individual flow path 205 for ink supply connected to the IN manifold 111, respectively. ~ SV5 is configured so that the flow rate can be adjusted manually. As a result, the amount of ink supplied to the first to fifth heads HD1 to HD5 can be more reliably made uniform. The sixth to tenth individual solenoid valves SV6 to SV10 provided in the sixth to tenth individual flow paths 206 to 210 for ink discharge connected to the OUT manifold 112 are also configured so that the flow rate can be adjusted. There is.

As described above, in the ink circulation system, the air pressure in the circulation tank 102 is adjusted to the negative pressure Pn, and the air pressure in the supply tank 103 is adjusted to the positive pressure Pp. Therefore, as shown in FIG. 3, a decompression adjusting device 152 is connected to the circulation tank 102 in order to adjust the pressure inside the circulation tank 102 to a negative pressure (pressure lower than the atmospheric pressure) Pn, and a supply tank is connected to the circulation tank 102. A pressure adjusting device 153 is connected to 103 in order to adjust the internal pressure to a positive pressure (pressure higher than atmospheric pressure) Pp. The decompression adjustment device 152 is composed of, for example, a vacuum pump, a decompression buffer tank, a pressure adjustment mechanism (regulator), and the like, and the decompression adjustment device 152 is composed of, for example, a compressor, a pressure buffer tank, a pressure adjustment mechanism (regulator), and the like. Will be done. The operations of the depressurization adjusting device 152 and the pressurizing adjusting device 153 are configured to be controllable by the control unit 50 as described later.

FIG. 4 is a block diagram showing a hardware configuration of the control unit 50 in the present embodiment. The control unit 50 includes a CPU (Central Processing Unit) 511, a ROM (Read Only Memory), and a RAM (Random Access Memory) 513, and controls the flow and temperature of the ink in the ink circulation system shown in FIG. As an interface for this purpose, a flow path valve control interface 521, a head control interface 522, a pressure control interface 523, a heater control interface 525, a target temperature setting interface 527, and a temperature monitoring interface 259 are provided, and each of these control units 50 is provided. The components 511,513,515,521,522,523,525,527,529 are connected to each other via the system bus. An ink circulation control processing program is stored in the ROM 512, and the ink flow and temperature in the ink circulation system are controlled by executing the ink circulation control processing program while the CPU 511 uses the RAM 513 as a working memory. Will be done. Ink droplet ejection control of the heads HD1 to HD5 is performed based on the pattern formation data.

Here, in the flow path valve control interface 521, the CPU 511 opens and closes the first and second common path solenoid valves SV11 and SV12 and the bypass solenoid valve SV13, and opens and closes the first to tenth individual solenoid valves SV1 to SV10. It is an interface for controlling. The head control interface 522 transmits pattern formation data to the heads HD1 to HD5 and ejects droplets (ink droplets) from the heads HD1 to HD5 to form a pattern based on the pattern formation data by the heads HD1 to HD5. Interface for. When pattern formation data having different contents are transmitted to the heads HD1 to HD5, the amount of ink ejected from the heads HD1 to HD5 may be non-uniform. The pressure control interface 523 is an interface for controlling the decompression adjusting device 152 and the pressurizing adjusting device 153 for adjusting the air pressures of the circulation tank 102 and the supply tank 103, respectively. The heater control interface 525 is an interface for controlling ON / OFF of the heating tube heater HE12, the IN side common manifold heater HE13, and the head individual block heaters HE1, HE3, HE5, HE7, HE9. The target temperature setting interface 527 is the target temperature Tk1 of the heating tube temperature controller TR12, the target temperature Ti1 of the IN side common manifold temperature controller TR13, and the targets of the head individual block temperature controller TR1, TR3, TR5, TR7, TR9. It is an interface for setting the temperature Th1.

The system bus in the control unit 50 controls the X-axis direction moving mechanism 3, the Y-axis direction moving mechanism 4, and the elevating mechanism 5 shown in FIG. 1, and controls the amount of ink ejected from the heads HD1 to HD5. The interface for doing this is also connected to the system bus. Further, the solder resist pattern forming processing program is also stored in the ROM 512, and the CPU 511 executes the solder resist pattern forming processing program while using the RAM 513 as a working memory, thereby performing the X-axis via their interfaces. A solder resist pattern is formed on the printed circuit board placed on the table 10 by controlling the directional movement mechanism 3, the Y-axis direction movement mechanism 4, and the elevating mechanism 5 and controlling the ink ejection from the heads HD1 to HD5. Will be done. Since the details of these configurations and operations are the same as those in the prior art and are not directly related to the features of the present embodiment, the description thereof will be omitted.

<3. Operation of ink circulation device>
Next, the operation of the ink circulation device according to the present embodiment will be described by explaining the control process based on the ink circulation control processing program with reference to FIGS. 2 and 3 and FIG. FIG. 5 is a flowchart showing a control process for controlling the flow and temperature of the ink in the ink circulation device according to the present embodiment (hereinafter referred to as “ink circulation control process”). In the present embodiment, when the ink circulation device is started, the ink circulation control process of FIG. 5 is started. In this ink circulation control process, the CPU 511 in the control unit 50 uses the interface 521 based on the ink circulation control process program. Each part in the ink circulation device is controlled as follows via ~ 529. In this ink circulation device, when it is started, the first and second liquid feeding pumps EP1 and EP2 start to operate, and then the first one according to the detection result of the level sensor in each of the tanks 101 to 103. And the operation of the second liquid feed pumps EP1 and EP2 is controlled. The details of this configuration are the same as before.

In the ink circulation control process in the present embodiment, first, a start-up temperature control sequence for removing air bubbles in the ink circulation system and shortening the start-up time is executed (S100). In this start-up execution sequence, the initial setting of the flow path valve (S102), the initial setting of the tank pressure (S104), and the initial setting of the temperature controller (S106) are performed.

In the initial setting (S102) of the flow path valve, the first to tenth individual solenoid valves SV1 to SV10 as head individual valves are closed, and the bypass solenoid valve SV13 as an IN-OUT common manifold valve is opened.

In the initial setting of the tank pressure (S104), the air pressure Pp in the supply tank 103 is set to the high positive pressure value PpH, and the air pressure Pn in the circulation tank 102 is set to the high negative pressure value PnH. In the present embodiment, as the set value of the pressure (positive pressure) Pp in the supply tank 103, at least a high positive pressure value PpH which is a predetermined positive pressure value having a relatively large difference from the atmospheric pressure and the atmospheric pressure are used. A low positive pressure value PpL, which is a predetermined positive pressure value with a relatively small difference, is prepared, and at least the difference from the atmospheric pressure is relatively large as a set value of the pressure (negative pressure) Pn in the circulation tank 102. A high negative pressure value PnH, which is a large predetermined negative pressure value, and a low negative pressure value PnL, which is a predetermined negative pressure value with a relatively small difference from the atmospheric pressure, are prepared.

In the initial setting (S106) of the temperature controller, the heating tube heater HE12 and the IN side common manifold heater HE13 are turned on. Further, the ink temperature in the IN manifold 111 is acquired from the IN manifold liquid temperature sensor TS6 as the IN side common manifold liquid temperature TSt6, and the target temperature Tk1 of the heating tube heater HE12 is set to the heating tube based on the IN side common manifold liquid temperature TSt6. The temperature controller TR12 is set, and the target temperature Ti1 of the IN side common manifold heater HE13 is set to the IN side common manifold temperature controller TR13. As a result, the heating tube heater HE12 is heated to the corresponding target temperature Tk1, and the IN side common heater HE13 is heated to the corresponding target temperature Ti1. Further, the head individual block heaters HE1, HE3, HE5, HE7, and HE9 are turned on. Further, based on the head thermistor temperatures TSt1 to TSt5, a predetermined temperature Th1 is set as a target temperature in the head individual block temperature controllers TR1, TR3, TR5, TR7, and TR9. As a result, the ink temperature in the individual blocks 121, 123, 125, 127, 129 is heated to the temperature Th1.

When the start-up temperature control sequence (S100 consisting of S102 to S106) as described above is completed, the process waits until the IN side common manifold liquid temperature TSt6 reaches the predetermined temperature T1 (S110).

FIG. 6 shows the ink flow in the ink circulation system during this standby period, that is, the ink in the ink circulation system during the period from the execution of the start-up sequence (S100) to the start of the steady temperature control sequence (S120). It is a figure which shows the flow of. During this standby period, the first to tenth individual solenoid valves SV1 to SV10 as head individual valves are closed, and the bypass solenoid valves SV13 as IN-OUT common manifold valves are open. Ink does not flow through the first to tenth individual flow paths 201 to 210, and the supply tank 103 → IN manifold 111 → bypass flow path 215 → OUT manifold 112 → fourth common flow path 214 → circulation tank 102 → second. Ink circulates in the common flow path 212 → supply tank 103. At this time, since the atmospheric pressure Pp of the supply tank 103 is a high positive pressure value PpH and the atmospheric pressure Pn of the circulation tank 102 is a high negative pressure value PnH, the ink of the ink is compared with that during the steady operation after the steady temperature control sequence described later. The flow rate (circulation amount) increases.

When the IN side common manifold liquid temperature TSt6 reaches the predetermined temperature T1, the steady temperature control sequence (S120) is started. In this steady temperature control sequence, the flow path valve is constantly set (S122), the tank pressure is constantly set (S124), and the temperature controller is constantly set (S126).

In the steady setting of the flow path valve (S122), the first to tenth individual solenoid valves SV1 to SV10 as head individual valves are opened, and the bypass solenoid valve SV13 as an IN-OUT common manifold valve is closed.

In the steady setting of the tank pressure (S124), the air pressure Pp in the supply tank 103 is set to a low positive pressure value PpL, and the air pressure Pn in the circulation tank 102 is set to a low negative pressure value PnL.

In the steady setting (S126) of the temperature controller, the heating tube heater HE12 is continuously turned on, and the IN side common manifold heater HE13 is also continuously turned on. Further, the IN side common manifold liquid temperature TSt6 is acquired from the IN manifold liquid temperature sensor TS6, and the target temperature Tk2 of the heating tube heater HE12 is set in the heating tube temperature controller TR12 based on the IN side common manifold liquid temperature TSt6. , The target temperature Ti2 of the IN side common manifold heater HE13 is set to the IN side common manifold temperature controller TR13. Here, these set values Tk2 and Ti2 are selected so that all of them are larger than any of the above set values Tk1 and Ti1 in the start-up temperature control sequence.

Further, the head individual block heaters HE1, HE3, HE5, HE7, HE9 are continuously turned on, and the head individual block temperature controllers TR1, TR3, TR5, TR7, and TR9 are determined based on the head thermistor temperatures TSt1 to TSt5. By setting the temperature Th2 as the target temperature, the ink temperature in the individual blocks 121, 123, 125, 127, 129 is heated to the temperature Th2. Here, the predetermined temperature Th2 is selected to be higher than the predetermined temperature Th1 in the start-up temperature control sequence (Th2> Th1).

When the steady temperature control sequence (S120 consisting of S122 to S126) as described above is completed, the inks of the heads HD1 to HD5 are in a steady operation state in which the inks of the heads HD1 to HD5 are maintained at the target temperature (the temperature corresponding to the predetermined temperature Th2).

FIG. 7 is a diagram showing the flow of ink in the ink circulation system in this steady operation state. In this steady operation state, the first to tenth individual solenoid valves SV1 to SV10 as head individual valves are open, and the bypass solenoid valves SV13 as IN-OUT common manifold valves are closed. As described above, ink does not flow in the bypass flow path 215, and the supply tank 103 → IN manifold 111 → 1st to 5th individual flow paths 201 to 205 → 1st, 3rd, 5th, 7th and 9th individual blocks. 121,123,125,127,129 → 1st to 5th heads HD1 to HD5 → 2nd, 4th, 6th, 8th and 10th individual blocks 122, 124, 126, 128, 130 → 6th to 6th 10 Ink circulates in the order of individual flow paths 206 to 210 → OUT manifold 112 → fourth common flow path 214 → circulation tank 102 → second common flow path 212 → supply tank 103. At this time, the atmospheric pressure Pp of the supply tank 103 is a low positive pressure value PpL, and the atmospheric pressure Pn of the circulation tank 102 is a low negative pressure value PnL. Ink circulates.

While maintaining the above steady operation state, the heads HD1 to HD5 perform pattern formation on the printed circuit board placed on the table. That is, the heads HD1 to HD5 eject ink based on the pattern formation data. Since the pattern formation data transmitted to the heads HD1 to HD5 usually have different contents, the heads HD1 to HD5 eject different amounts of ink. In the present embodiment, the temperature controllers TR1, TR3, TR5, TR7, and TR9 are interposed in the individual flow paths 201 to 205, and the temperature controllers TR1, TR3, TR5, TR7, and TR9 are the individual flow paths 201 to 205. The temperature is controlled so that the temperature of the ink flowing through the ink is uniform. Therefore, even when the heads HD1 to HD5 eject different amounts of ink, ink having a uniform temperature can be supplied to the heads HD1 to HD5. As a result, high quality can be ensured for pattern formation on the printed circuit board.

Further, in the present embodiment, the temperature controllers TR1, TR3, TR5, TR7, and TR9 are arranged at positions close to the heads HD1 to HD5. That is, the pipe lengths of the individual flow paths 201 to 205 from the temperature controllers TR1, TR3, TR5, TR7, TR9 to the heads HD1 to HD5 are the temperature controllers TR1, TR3, TR5, TR7, from the IN side common manifold 111. The length is shorter than the pipe length of the individual flow paths 201 to 205 up to TR9. As a result, the ink having high temperature uniformity adjusted by the temperature controllers TR1, TR3, TR5, TR7, and TR9 can be supplied to the heads HD1 to HD5 at almost the same temperature. As a result, it is possible to further improve the quality of pattern formation on the printed circuit board.

Further, even if there are variations in the pipe lengths and pipe resistances of the individual flow paths 201 to 205, the individual path solenoid valves SV1 to SV5 (thus, ink) interposed in the individual flow paths 201 to 205. The flow rate can be adjusted individually for each head HD1 to HD5) and the temperature controller TR1, TR3, TR5, TR7, TR9 (this makes it possible to individually adjust the ink temperature for each head HD1 to HD5). It becomes possible to supply ink having a uniform temperature to the heads HD1 to HD5. That is, the head HD1 corrects the variation in ink temperature that may occur in the individual flow paths 201 to 205 interposed between the IN side common manifold 111 and the heads HD1 to HD5 with the temperature controllers TR1, TR3, TR5, TR7, and TR9. It becomes possible to supply to ~ HD5.

The ink circulation device according to the present embodiment includes both a temperature controller TR13 capable of heating the entire ink circulation circuit and temperature controllers TR1, TR3, TR5, TR7, and TR9 that individually heat the heads HD1 to HD5. I have. Therefore, when it is necessary to raise the ink temperature in a short time as in the start-up temperature control sequence S100 (see FIG. 5), the temperature controller TR13 is used to supply the ink temperature to the heads HD1 to HD5. In the steady temperature control sequence S120 (see FIG. 5) in which it is necessary to precisely adjust the temperature, the temperature controller TR13 and the temperature controllers TR1, TR3, TR5, TR7, and TR9 can be used in combination. As a result, the temperature controller can be operated efficiently.

<4. Effect>
In the present embodiment as described above, as shown in FIG. 2, ink is supplied to the five heads HD1 to HD5 in one ink circulation system, and the IN side (upstream side) and OUT side (upstream side) and OUT side (upstream side) of these heads HD1 to HD5 ( The IN manifold 111 and the OUT manifold are provided on the downstream side), respectively. In the steady operation state, the first to fifth individual flow paths 201 to 205, the first to fifth heads HD1 to HD5, and Ink circulates through the five flow paths from the sixth to the tenth individual flow paths to the OUT manifold 112, so that the ink is individually supplied to the five heads HD1 to HD5. Further, as described above, these five flow paths are configured so that the length and the pipe resistance of the pipes are the same as each other. As a result, the ink flow rates in the five flow paths for supplying ink to the five heads HD1 to HD5 are made uniform. Further, in the present embodiment, the individual flow rate solenoid valves SV1 to SV5 provided in the individual flow paths 201 to 205 on the IN side of the five heads HD1 to HD5 are all configured so that the flow rate can be adjusted. Therefore, if the ink flow rates in the five flow paths are still not sufficiently uniform even with the above configuration, the flow rates in the five flow paths can be adjusted by adjusting the flow rates with the individual solenoid valves SV1 to SV5. The ink flow rate can be reliably made uniform.

Further, in the present embodiment, in the third common path 213, the ink is heated by the temperature controller TR12 including the heater HE12 and adjusted to a desired temperature, and in the IN manifold 111, the temperature is adjusted including the IN side common manifold heater HE13. Ink is heated by the device (IN side common manifold temperature controller) TR13 and adjusted to a desired temperature. In addition, of the individual blocks 121 to 130, the IN side individual blocks 121, 123, 125, 127, 129 Ink also in the individual blocks 121, 123, 125, 127, 129 on the IN side by the temperature controller (head individual block temperature controller) TRi including the head individual block heater HEi provided in each (i = 1 to 5). The temperature is regulated and homogenized. Thereby, the ink temperature in the five heads HD1 to HD5 to which the ink is supplied by one ink circulation system can be surely made uniform. When a relatively high-viscosity ink such as solder resist ink is used in the ink circulation device, such temperature equalization is used to equalize the ink ejection amount from the five heads HD1 to HD5. It is valid.

Further, in the present embodiment, the start-up temperature control sequence is executed when the ink circulation device is started (see FIG. 5), so that the first to tenth individual solenoid valves SV1 to SV10 are closed and the supply tank 103. With the atmospheric pressure Pp set to a high positive pressure value PpH and the atmospheric pressure Pn of the circulation tank 102 set to a high negative pressure value PnH, the supply tank 103 → IN manifold 111 → bypass flow path 215 → OUT manifold 112 → circulation tank 102 → Ink circulates through a route called the supply tank 103 (see FIG. 6). As a result, the air bubbles mixed in while the ink circulation device is stopped are prevented from flowing to the head side (heads HD1 to HD5), and the air bubbles mixed in are discharged to the outside of the tank in a shorter time than before. In addition, since the flow rate of ink increases, the temperature rise of the ink and the piping portion forming the flow path is accelerated, and the time required to reach the steady ink temperature is shortened as compared with the conventional case.

Further, according to the present embodiment, since the air pressure Pn of the circulation tank 102 and the air pressure Pp of the supply tank 103 can be changed, this function is used to weakly purge the ink or change the meniscus pressure for cleaning. It is also possible to provide the function to do. Further, by independently controlling the opening and closing of the individual solenoid valves SV1 to SV10 provided on the IN side and the OUT side of the heads HD1 to HD5, it is possible to perform ink purging and cleaning for each head. Furthermore, by using the always-closed solenoid valves as these individual path solenoid valves SV1 to SV10, even if the ink circulation device or the device provided with it does not have a holding power supply (standby power supply), the head It is possible to prevent ink from flowing out from HD1 to HD.

<5. Modification example>
The present invention is not limited to the above-described embodiment, and various modifications can be further made without departing from the scope of the present invention. For example, in the above embodiment, one ink circulation system supplies ink to five heads HD1 to HD5 (see FIG. 2), but one ink circulation system supplies ink to a plurality of heads of 4 or less or 6 or more. It may be configured to be.

Further, the ink circulation device according to the above embodiment is a device that constitutes the main part of the solder resist inkjet device, and solder resist ink is used, but the present invention is an ink circulation device that uses other types of ink. It is also applicable to. However, the present invention is particularly effective when an ink having a relatively high viscosity such as a solder resist ink is used.

50 ... Control unit 102 ... Circulation tank 103 ... Supply tank 111 ... IN side common manifold (IN manifold)
112 ... OUT side common manifold (OUT manifold)
121-130 ... Head individual block 152 ... Decompression adjustment device 153 ... Pressurization adjustment device 211-214 ... Common flow path 215 ... Bypass flow path 201-205 ... Individual flow path on the IN side (individual flow path for ink supply)
206 to 210 ... Individual flow path on the OUT side (individual flow path for ink discharge)
SV11, SV12 ... Common road solenoid valve SV13 ... Bypass solenoid valve (bypass valve)
SV1 to SV5 ... (IN side) individual solenoid valve (supply side individual valve)
SV6 to SV10 ... (OUT side) individual solenoid valve (discharge side individual valve)
CV1 to CV10 ... Coupler TR12 ... Heating tube temperature controller TR13 ... IN side common manifold temperature controller TS1 to TS5 ... Head thermistor TS6 ... IN manifold liquid temperature sensor TR1, TR3, TR5, TR7, TR9 ... Head individual block temperature controller HD1 to HD5 ... Inkjet head (head)

Claims (7)

An ink circulation device that circulates ink in one circulation circuit that passes through a plurality of ink circulation type inkjet heads and supplies ink to the plurality of inkjet heads.
In the circulation circuit, the supply side manifold and the discharge side manifold arranged on the upstream side and the downstream side of the plurality of inkjet heads, respectively,
A plurality of supply-side branch paths for forming a part of the circulation circuit and supplying ink in the supply-side manifold to the plurality of inkjet heads, respectively.
A plurality of discharge side branch paths for forming a part of the circulation circuit and discharging ink in the plurality of inkjet heads to the discharge side manifold, respectively.
A common temperature controller that includes a heater that heats the ink in the supply side manifold and regulates the temperature of the ink.
A plurality of individual temperature controllers each including a heater for heating ink supplied to each of the plurality of inkjet heads via the plurality of supply-side branch paths and adjusting the temperature of the ink at the same target temperature. Ink circulation device to be equipped. The plurality of branch paths from the supply-side manifold to the discharge-side manifold via the plurality of supply-side branch paths and the plurality of discharge-side branch paths are configured so that the pipe length and the piping resistance are the same. The ink circulation device according to claim 1. The ink circulation device according to claim 2, further comprising a plurality of individual valves for opening and closing each of the plurality of branch paths. The ink circulation device according to claim 3, wherein the plurality of individual valves are configured so that the flow rate can be adjusted. A plurality of supply-side individual valves that open and close the plurality of supply-side branch paths, respectively.
The ink circulation device according to claim 2, further comprising a plurality of discharge side individual valves for opening and closing each of the plurality of discharge side branch paths. Bypass flow path from the supply side manifold to the discharge side manifold,
The ink circulation device according to claim 5, further comprising a bypass valve for opening and closing the bypass flow path. A supply tank for storing ink to be supplied to the plurality of inkjet heads via the supply side manifold, and a supply tank.
A circulation tank that stores ink discharged from a plurality of inkjet heads via the discharge side manifold, and
A flow path for discharging ink from the discharge side manifold to the circulation tank, and
A flow path for sending ink from the circulation tank to the supply tank,
A flow path for supplying ink from the supply tank to the supply side manifold, and
A pressure adjusting device that sets the air pressure in the supply tank to a positive pressure,
A decompression adjustment device that sets the air pressure in the circulation tank to a negative pressure,
The plurality of supply-side individual valves, the plurality of discharge-side individual valves, the bypass valve, the pressure adjusting device, and a control unit for controlling the depressurizing adjusting device are further provided.
The control unit
When the ink circulation device is activated,
The plurality of supply-side individual valves and the plurality of discharge-side individual valves so that the plurality of supply-side individual valves and the plurality of discharge-side individual valves are closed and the bypass valves are opened in a predetermined standby period. Control the valve and the bypass valve,
In the standby period, the difference between the positive pressure set as the pressure of the supply tank and the atmospheric pressure is the steady positive pressure set as the pressure of the supply tank in the steady operation state of the ink circulation device. The difference between the negative pressure set as the pressure of the circulation tank and the atmospheric pressure, which is larger than the difference from the atmospheric pressure, is the negative pressure set as the pressure of the circulation tank in the steady operation state of the ink circulation device. The pressurization adjustment device and the decompression adjustment device are controlled so as to be larger than the difference between the steady negative pressure and the atmospheric pressure.
After the waiting period has passed,
The plurality of supply-side individual valves, the plurality of discharge-side individual valves, and the said Control the bypass valve,
The ink circulation device according to claim 6, wherein the pressure adjusting device and the depressurizing adjusting device are controlled so that the air pressure in the supply tank becomes the steady positive pressure and the air pressure in the circulation tank becomes the steady negative pressure.

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