JPH1158770A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize the structure of a print head while enhancing the maintenance work thereof by securing a three-way valve to an ink heater or a member secured with the ink heater thereby connecting an ink supply channel. SOLUTION: An ink supplied to the inner channel 12 of a ink heater 4 is heated by the heating surface 13 thereof and passed through the channel joint 14 of the ink heater to the channel joint 15 of a three-way valve. Furthermore, the ink is fed into a channel 16 in the three-way valve 3 and passed through a jet coupling 17 to a jet tube 8. When a cleaning liquid is fed to the jet tube 8, power supply to the three-way valve 3 is interrupted and the cleaning liquid is fed from a cleaning tube through a jet coupling 20 to the jet tube 8. In the case of failure of the three-way valve 3 or the ink heater 4, they can be separated easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial ink jet recording apparatus, and more particularly to printing such as arrangement of parts of a print head in which nozzles for forming ink particles for performing printing are arranged, connection between parts, and the like. It relates to the configuration of the head section.

[0002]

2. Description of the Related Art In a continuous ink jet recording apparatus, a print head section has a nozzle for ejecting ink particles, an ink supply passage for supplying ink to the nozzle,
Charging electrode for charging ink particles, deflection electrode for deflecting ink particles, gutter and collection channel for collecting ink to reuse ink particles not used for printing, suitable for charging ink particles An auto-phase sensor for measuring various timings is provided. Printing can be performed with at least these parts.

However, in order to improve reliability and performance, a cleaning liquid ejection flow path for preventing ink sticking to the nozzle portion, a solenoid valve for switching between the cleaning liquid and ink, a filter for preventing clogging of the nozzle portion by foreign matter, In some cases, an ink heating device for controlling the ink temperature in order to keep the production of ink particles optimal, a solenoid valve or a check valve for preventing backflow of ink when the device is stopped, and the like may be provided. Usually, these components are selectively adopted and arranged in the print head unit.

Conventionally, the connection between these components is made by a tube, so that the structure is complicated. Also, the connection between these parts and the tube is made in such a manner that the tube does not come off even if the part is removed from the print head.

[0005] In addition, a component serving as a base of a print head is generally formed of a metal, a substrate, or a resin.
They are provided with screw holes so that the parts can be fixed with screws, but are limited to the function for mounting said parts.

[0006]

An industrial ink jet recording apparatus is used for printing on a product on a production line. However, depending on the configuration of the production line and the timing of printing, the printing of the ink jet recording apparatus is performed. The place where the head unit is attached is determined. For this reason, the ink jet recording apparatus drives a circulating system including a pump and a bottle of ink for pressurizing and recovering ink, and drives a nozzle and a solenoid valve, and charges and deflects ink particles. A structure that separates into a main unit consisting of a substrate for controlling them in a software manner and a print head that actually creates and prints in particles, so that the print head can be easily installed on the production line. It is made.

On the other hand, in addition to components essential for printing, components for preventing nozzle clogging and stabilizing the state of ink ejected from the nozzles are mounted on the print head to improve reliability and performance. Therefore, it is desirable to mount components for improving reliability and performance other than components essential for printing. However, when these components are mounted, in addition to increasing the production cost, there is a problem in that the dimensions of the print head section are increased, and workability in maintenance work on those components is also a problem.

When the size of the print head becomes large, it may be difficult to mount the print head on a production line. In the print head unit, the direction of ink ejection is up and down, left and right, and the rotation angle when the ink ejection direction is set as an axis is also 360 due to the constraints from the structure of the production line.
There is a need to be able to attach in any direction and angle. Due to such features, it is required that the print head can be mounted in any direction and angle in a small space, but it is necessary to increase the reliability and performance without increasing the size of the print head. Is a problem.

Also, reliability other than parts indispensable for printing,
The components for improving the performance are, specifically, solenoid valves, heaters,
The problem is how to improve the handleability of the check head and the like in terms of the print head structure in terms of the parts replacement work and the like, assuming that maintenance work of those parts is required.

In addition, by appropriately arranging, structuring, and connecting the components mounted on the print head, it is possible to improve the effect of the purpose of use of those components and to simplify the structure. It is a matter of how you plan.

An object of the present invention is to solve the above problems.
An object of the present invention is to provide an ink jet recording apparatus that optimizes the structure of a print head for mounting components for improving reliability and performance, and further improves the workability of print head maintenance work.

[0012]

In order to achieve the above object, the present invention provides an ink supply passage for supplying pressurized ink, and a nozzle for ejecting the supplied ink as ink particles. A print head section of an ink jet recording apparatus having a cleaning liquid supply flow path for supplying a cleaning liquid to the nozzle section; an ink heating device for heating ink supplied to the nozzle section; and A three-way valve for switching between an ink supply flow path and the cleaning liquid supply flow path, and the ink supply flow path is formed by fixing the three-way valve to the ink heating device or a member to which the ink heating device is fixed. It is characterized by being connected.

Another feature of the present invention is that the ink heating device is arranged upstream of the three-way valve for the ink flowing in the ink supply flow path.

Another feature of the present invention is that the filter has a filter for removing foreign matters in the ink flowing in the ink supply path, and the filter is disposed near an ink supply flow path outlet of the three-way valve. It is characterized by having.

Another feature of the present invention is that the three-way valve and the wiring portion of the ink heating device are water-tightly isolated from the vicinity of the ink supply flow path.

Another feature of the present invention resides in a print head of an ink jet recording apparatus having an ink supply passage for supplying pressurized ink, and a nozzle for ejecting the supplied ink as ink particles. A first connection part of the flow path of a component having a flow path for flowing the ink, a second connection part of a tube for flowing the ink, the first connection part by fixing the component A second connection part is also fixed at the same time, and a flow path for flowing the ink is connected.

Another feature of the present invention is that it has a base for fixing the components constituting the print head, and the base is made of resin, and further has a part of the function of the components other than the fixing of the components. It is characterized by also serving as.

According to the present invention, there is provided an ink heating device for heating ink in order to keep the production of ink particles ejected from the nozzle optimal, and an ink supply device for supplying ink to a flow path connected to the nozzle portion. The connection of the flow path with the three-way valve that switches to the flow path and the cleaning liquid supply flow path without using a pipe such as a tube,
The airtightness of the connection part is maintained by directly inserting the connection part of the flow path of the three-way valve into the flow path connection part of the ink heating device and fixing the three-way valve.

In this way, when it is necessary to remove the three-way valve or the ink heating device, for example, for replacement thereof, it becomes easy for the user to disconnect the two.

In order to prevent nozzle clogging due to sticking of ink to the nozzle portion when the apparatus is stopped, the nozzle portion is washed. When the nozzle is washed, a flow path connected to the nozzle by a three-way valve is supplied to the solvent supply flow. Perform the operation of switching to the road. When cleaning the nozzle, in addition to the cleanability of the nozzle, if the cleanability of the flow path to the nozzle is poor, the nozzle cannot be sufficiently cleaned unless a large amount of cleaning liquid is used. Since the cleaning liquid used for cleaning the nozzle portion is collected in the ink bottle of the main body, using a large amount of the cleaning liquid causes a change in the physical properties of the ink. Therefore, it is preferable that the cleaning liquid be as small as possible. Therefore, it is necessary to improve the cleanability of the flow channel, but the most effective is to reduce the volume of the flow channel. According to the present invention, since the ink heating device is disposed on the upstream side of the three-way valve with respect to the direction in which ink flows, it is not necessary to clean the flow path inside the ink heating device. The passage is only the passage from the three-way valve to the nozzle.

The problem here is that, during printing, the ink heated by the ink heating device radiates heat until it passes through the three-way valve and is supplied to the nozzles. Although the temperature of the ink is lowered, according to the present invention, since the ink heating device and the three-way valve are directly connected,
Since the temperature of the heated ink hardly drops from the ink heating device to the three-way valve, the effect of the temperature drop on the heated ink due to the attachment of the three-way valve can be ignored.

Further, according to the present invention, since the filter is disposed near the outlet of the ink supply flow path of the three-way valve, there is no need to provide a special filter casing when installing the filter. In addition, foreign matter generated inside the three-way valve can be trapped in front of the nozzle.

Also, the three-way valve and the ink heating device require wiring because of the need to supply electricity. However, industrial ink jet recording devices often require quick-drying ink due to their characteristics, and flammable solvents. Because I often use
In order to prevent ignition, it is necessary to seal the wiring mounting portion and the connector portion so that the solvent does not come into contact with the electric components inside the three-way valve and the ink heating device. According to the present invention, since the wiring portion is water-tightly isolated from the vicinity of the ink supply flow path and the place where the solvent may be applied, it is not necessary to seal the mounting portion of the wiring and the connector portion alone. Becomes

Further, according to the present invention, the first connecting part of the flow path of the component having the flow path for flowing ink and the second connecting part of the tube for flowing the ink can be replaced by the part having the flow path for flowing the ink. By fixing, the first connection part and the second connection part are also fixed at the same time, and by connecting the flow path for flowing the ink, when the part is removed when the part is replaced, it is connected to it. The tube can be removed at the same time, so that workability can be improved and the number of parts can be reduced.

According to the present invention, a base for fixing a component constituting a print head is provided, and the base is made of resin, and further has a part of the function of the component other than fixing of the component. The number of parts can be reduced, and the heat insulating material of the ink heating device mounting portion can be eliminated.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A print head of an ink jet recording apparatus according to one embodiment of the present invention will be described below with reference to the drawings. 1 to 4 are denoted by the same reference numerals.

First, with reference to FIGS. 1 and 2, the arrangement and basic operation of components of a print head of an ink jet recording apparatus according to an embodiment of the present invention will be described. FIG. 1 shows the arrangement of components of the print head unit, and FIG. 2 shows the configuration of the ink heating device and the flow path of the three-way valve.

As shown in FIG. 1, a print head unit 1 is provided with a nozzle 2. In front of the nozzle 2, an electromagnetic three-way valve 3, an ink heating device 4, and a check valve 5 are arranged. When ejecting the ink particles 6 from the nozzle 2, the pressurized ink is sent from the supply tube 7, and the ink is supplied to the ink heating device 4. The ink supplied to the ink heating device 4 flows into the inside of the three-way valve 3 and the ejection tube 8
Through the nozzle 2. At this time, the three-way valve 3 is energized so that the ink heating device 4 and the flow path of the ejection tube 8 are conducted. When the air mixed in the nozzle 2 is removed, the nozzle 2 is kept ejected while the ink particles 6 are jetted.
The ink is sent from the inside to the circulation tube (a) 9, and the ink is circulated through the check valve 5 and the circulation tube (b) 10 to the ink jet recording apparatus main body (not shown).

When stopping the ink, the three-way valve 3 shuts off the flow path from the ink heating device 4 to the ejection tube 8, and instead supplies the cleaning tube 11 to the three-way valve 3 so that the ejection tube 8 is electrically connected. Is stopped, and the inside of the nozzle 2 is washed with the washing liquid supplied into the washing tube 11. The inside of the nozzle 2 is also cleaned by sucking the cleaning liquid supplied into the nozzle 2 from the circulation tube 9. When the cleaning of the nozzle 2 is completed, the supply of the cleaning liquid from the cleaning liquid tube 11 is stopped, and the ejection of the cleaning liquid from the nozzle 2 is stopped.

Next, the flow paths of the ink heating device 4 and the three-way valve 3 will be described with reference to FIG. The ink sent to the ink heating device channel 12 inside the ink heating device 4 is heated from the ink heating device heating surface 13 and passes through the ink heating device channel connection portion 14 to form a three-way valve. It flows to the flow path connection part 15. Further, the ink flows into the three-way valve passage 16 inside the three-way valve 3 and is supplied to the ejection tube 8 through the ejection joint 17. When the cleaning liquid is supplied to the ejection tube 8, the power supply to the three-way valve 3 is stopped, and the cleaning liquid in the cleaning tube 11 is supplied to the ejection tube 8 through the cleaning joint 20. A filter is provided at the outlet of the flow path in the three-way valve 3. Also, each part is an O-ring (a) 21 and an O-ring (b) 2
2. Sealed by O-ring (c) 23.

With such a configuration, in order to prevent nozzle clogging of the nozzle 2 due to sticking of ink which occurs when the ink is stopped, a three-way valve 3 is provided and the liquid supplied to the ejection tube 8 is switched between cleaning liquid and ink. be able to. In addition, the three-way valve 3 and the ink heating device 4 are fixed to the print head unit 1. However, by forming the three-way valve flow path connecting part 15 as shown in FIG. Channel connection with the heating device 4 can be performed. According to this method, when the three-way valve 3 and the ink heating device 4 are to be separated from each other, for example, when the three-way valve 3 or the ink heating device is out of order, it is possible to easily perform the maintenance work. it can.

Here, in consideration of the efficiency of the ink heating device, the ink heated by the ink heating device 4 radiates heat before reaching the nozzle 2, so that the ink should be located between the nozzle 2 and the three-way valve. Although it is better to dispose, according to the configuration of the present invention, there is almost no distance from the ink heating device 4 to the supply to the three-way valve 3.
When the ink is inserted between the nozzle and the nozzle 2, heat radiation of the ink occurs, and there is no problem that the temperature of the ink in the nozzle portion decreases. The temperature drop that occurs from the time when the ink heating device 4 is actually ejected to the time when the ink is ejected from the nozzle 2 is about 2 to 3 ° C. There is no problem if the ink heating device is driven in anticipation thereof.

The fact that the ink heating device 4 can be installed upstream of the three-way valve 3 with respect to the flow of ink is very advantageous when the nozzle 2 is washed.

Since the filter in FIG. 2 is disposed at the outlet of the flow path of the three-way valve 3, foreign matter flowing from the inside of the ink heating device 4 and the three-way valve 3 can be trapped. The filter can be easily replaced by removing the spout joint 17. Next, a seal structure of a wiring portion of the ink heating device 4 and the three-way valve 3 will be described with reference to FIG. In FIG. 3, a lead wire (a) 24 and a connector (a) 25 are attached to the ink heating device 4. Further, a lead wire (b) 26 and a connector (b) 27 are attached to the three-way valve 3. The ink heating device 4 and the three-way valve 3 are attached to the print head base 28, but the lead wires and connectors of the ink heating device 4 and the three-way valve 3 are packed (a) 29, packing (B) Sealed watertight by 30. Since the seal portion of the three-way valve 3 is a curved surface while the seal surface of the print head base 28 is a flat surface, the packing (a) 29 can be water-tightly isolated by using a sponge-like rubber that is independently foamed. it can.

Here, the ink heating device 4 and the three-way valve 3
, A voltage of 24 V is applied. However, industrial ink jet recording apparatuses are often required to use quick-drying inks due to their characteristics, and therefore, a flammable solvent is often used. To prevent the solvent or cleaning liquid from coming into contact with the electric parts inside the three-way valve 3 and the ink heating device 4 to prevent ignition, do not allow the solvent to ignite even if the solvent is applied to the mounting part of the wiring. The structure must be such that the solvent or the cleaning liquid is not applied.

In some cases, the print head unit 1 is washed when the print head unit 1 becomes dirty.
Parts that may be exposed to cleaning liquid or solvent, such as when cleaning
In a portion 32, which is watertightly isolated from and not exposed to the cleaning liquid and the solvent, a lead wire (a) 24, a connector (a) 25, and a lead wire (b) 2 of the ink heating device 4 and the three-way valve 3 are provided.
6. By arranging the connector (b) 27, a fire prevention structure is provided.

Next, the structure of connection between the flow path of the three-way valve 3 and the flow path of the washing tube 19 will be described with reference to FIG. The flow path connection portion is a typical example. In the print head portion according to the present embodiment, the flow path connection portion between the three-way valve 3 and the ejection tube 8, the check valve 5, the circulation tube (a) 9, and the circulation tube (b) are provided. 10) has the same structure.

In FIG. 4, the three-way valve 3 can be removed by removing the screw 33 and removing the three-way valve holding member 35 from the print head base 28. At the same time that the three-way valve 3 is removed, the joint support 3 of the print head base 28 is removed.
From FIG. 4, the washing joint 20 is to be detached, so that the ejection tube 8 and the three-way valve 3 are detached. At this time, the O-ring (c) 23 remains inside the three-way valve 3 unless it is intentionally removed.

By removing the three-way valve 3 in this manner, the tube connected to the three-way valve 3 is also removed.
Workability when replacing parts has been improved.

Although the print head base 28 is made of resin, other than fixing the components mounted on the print head, other functions such as a joint support portion 34 in FIG. 4 and a watertight isolation in FIG. , The structure of the print head unit 1 can be simplified and the number of components of the print head unit 1 can be reduced.

[0041]

According to the present invention, the structure of a print head for mounting components for improving reliability and performance can be optimized,
The workability of the print head maintenance work was improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a print head unit of an ink jet recording apparatus according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating a flow path of an ink heating device and a three-way valve of FIG. 1;

FIG. 3 is a diagram illustrating a seal of a wiring portion of an ink heating device and a three-way valve of FIG. 1;

FIG. 4 is a view showing a fixed portion of the three-way valve of FIG. 1 and a connection portion with a tube.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Print head part, 2 ... Nozzle, 3 ... Three-way valve, 4 ... Ink heating device, 5 ... Check valve, 6 ... Ink particles, 7 ... Supply tube, 8 ... Spray tube, 9 ... Circulation tube (a) ,
10: circulation tube (b), 11: washing tube, 12
... Ink heating device flow path, 13 ... Ink heating device heating surface, 14 ... Ink, 15 ... Three-way valve flow path connection part, 16 ... Three-way valve flow path, 17 ... Ejection joint, 19 ... Cleaning liquid, 20 …
Cleaning joint, 21 O-ring (a), 22 O-ring (b), 23 O-ring (c), 24 Lead wire (a), 25 Connector (a), 26 Lead wire (b), 27: connector (b), 28: print head base, 29: packing (a), 30: packing (b), 3
Reference numeral 1 denotes a portion which is likely to be exposed to a cleaning liquid or a solvent, 32 denotes a portion which is not exposed to a cleaning liquid or a solvent, 33 denotes a screw, 34 denotes a joint support portion, and 35 denotes a three-way valve press fitting.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Takashi Takahashi 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside the Taga Headquarters, Hitachi, Ltd.Electrical Equipment Division

Claims (6)

[Claims] An ink supply passage for supplying pressurized ink, a nozzle for ejecting the supplied ink as ink particles, and a cleaning liquid supply passage for supplying a cleaning liquid to the nozzle. In a print head unit of the ink jet recording apparatus, the print head unit includes an ink heating device for heating ink supplied to the nozzle unit, and a three-way valve for switching between the ink supply channel and the cleaning liquid supply channel connected to the nozzle unit. An ink jet recording apparatus, wherein the ink supply flow path is connected by fixing the three-way valve to the ink heating device or a member to which the ink heating device is fixed. 2. An ink jet recording apparatus according to claim 1, wherein said ink heating device is arranged upstream of said three-way valve for ink flowing in said ink supply flow path. 3. A filter according to claim 1, further comprising a filter for removing foreign matter in the ink flowing in the ink supply path, wherein the filter is disposed near an ink supply flow path outlet of the three-way valve. An ink jet recording apparatus characterized by the following. 4. An ink jet recording apparatus according to claim 1, wherein the three-way valve and a wiring portion of the ink heating device are water-tightly isolated from the vicinity of the ink supply flow path. 5. A flow path for flowing said ink in a print head section of an ink jet recording apparatus having an ink supply flow path for supplying pressurized ink and a nozzle section for ejecting said supplied ink as ink particles. The first connection portion of the flow path of the component having a, the second connection portion of the tube through which the ink flows, the first connection portion and the second connection portion by fixing the component An ink jet recording apparatus characterized in that the ink is also fixed at the same time and a flow path for flowing the ink is connected. 6. A printing apparatus according to claim 1, further comprising a base for fixing a component constituting the print head, wherein the base is formed of resin, and further includes a function of the component other than the fixing of the component. An ink jet recording apparatus characterized by also serving as a unit.