JPH106524A - Circulation system of inkjet recording device - Google Patents

Abstract

(57) [Summary] A piping system that improves the air bleeding property in a recording nozzle at the time of starting an ink jet recording apparatus, shortens the operation preparation time required at the time of starting the apparatus, and has a stable recovery performance. I will provide a. A chamber section (1) having a partition wall that hinders the ink flow direction is provided on the side of an ink circulation path near a junction of an ink circulation path and a recovery path. The ink flowing through the ink circulation path flows into the chamber section 1 having a wide gap with respect to the piping tube.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention selectively charges ink particles continuously ejected from a recording nozzle, deflects the charged ink particles by a deflecting electric field, and prints characters and symbols on a printing object. Print. Other inks are related to a charge control type ink jet recording apparatus that is caught and collected by gutter.

[0002]

2. Description of the Related Art When an ink-jet recording apparatus of a charge control type is stopped, it is necessary to keep ink from remaining in recording nozzles in order to prevent nozzle clogging with ink. However, in the case of a recording nozzle that has a vibration source inside which makes ink into particles, the ink is simply supplied to the recording nozzle due to structural restrictions such as a large gap inside the nozzle or a complicated internal structure. There is a problem that the air that has once entered the recording nozzle cannot easily escape through the mere execution of the operation.

If the air that has entered the recording nozzle cannot be completely removed, the residual air will act as a damper, making it difficult for the vibration energy of the vibration source to be transmitted 100% to the ink, or the air may suddenly escape from the nozzle of the recording nozzle. This causes problems such as disturbing the jet flow of ink at that moment, changing the timing at which ink particles are created, and causing printing disturbance. In order to solve these problems, it is necessary to immediately remove the air contained in the recording nozzle when the apparatus is started.

In order to release air from the recording nozzles when the apparatus is started, it is necessary to generate a large amount of ink flow inside the recording nozzles. To achieve this function, for example,
International Publication Number WO91 / 170
As described in 52, in addition to the ink supply path, an ink circulation path which is an air release path is connected to the recording nozzle,
Further, an electromagnetic valve is disposed on the side opposite to the recording nozzle of the present ink circulation path, and has a piping system structure capable of flowing a large amount of ink from a supply port to a discharge port of the recording nozzle at an arbitrary timing.

[0005]

As described above, since the ink circulation path also serves as a suction path for ink inside the recording nozzles when the apparatus is stopped, the side opposite to the recording nozzles must be connected to a negative pressure pump. On the other hand, a charge control type ink jet recording apparatus requires an ink recovery path in which ink not used for printing is caught by gutter and returned to the ink container, and this path also has a negative pressure on the anti-gutter side similarly to the ink circulation path. Must be connected to the pump.

[0006] Under these conditions, if a negative pressure pump is separately installed in each of the ink circulation path and the ink recovery path, a problem such as an increase in the size of the apparatus occurs. Therefore, usually, as described in the above-mentioned conventional example, the negative pressure pump is shared by the two paths, and a piping system is configured such that both paths join immediately before the negative pressure pump.

The problem with this piping system is that, in order to efficiently discharge the residual air in the recording nozzle in a short period of time, the maximum flow rate of ink that does not impair the straightness of the ejected ink must be supplied to the ink supply port of the recording nozzle. It is necessary to supply a rapid change in the flow velocity by opening / closing a circulation solenoid valve provided in the ink circulation path. But,
When the device is started, the path is suctioned by the negative pressure pump until the circulating solenoid valve opens, so it is maintained at a high vacuum, and at the moment the circulating solenoid valve opens, high-speed ink is merged into the ink circulation path and the ink recovery path. Flow into the point. At this time, since the flow rate of the ink is high, all the flowing ink cannot be drawn into the negative pressure pump side, and flows back to the gutter side to make it impossible to collect the ink particles. Therefore, also in the conventional example, a restrictor for restricting the flow rate is provided in the ink circulation path. As a result, there is a problem that the air bleeding property in the recording nozzle is reduced and it takes time to prepare for the operation of the ink jet recording apparatus. SUMMARY OF THE INVENTION It is an object of the present invention to provide a piping system of an ink jet recording apparatus which can maintain the recovery performance, improve the air bleeding property in the recording nozzle, and reduce the operation preparation time required at the time of starting the apparatus. .

[0008]

In order to achieve the above object, the present invention provides a chamber having a partition wall on the side of an ink circulation path near a junction of an ink circulation path and a recovery path, which obstructs the flow direction of ink. Set up the department. When the ink flows into the chamber having a wide gap with respect to the pipe tube, the ink flow velocity is reduced, and then the ink collides with the partition wall in the flow direction, and the flow velocity is further reduced.
Therefore, the ink flowing into the junction of the circulation path and the recovery path has a sufficiently low speed, and is all drawn into the negative pressure pump side, and the recovery performance is stabilized without flowing back to the gutter side.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a circulating system of a charge control type ink jet recording apparatus according to the present invention and the principle of recording. In the drawing, a solid line indicates an ink supply path, a broken line indicates an ink recovery path, a dashed line indicates an ink circulation path, and a two-dot chain line indicates an ink physical property adjustment path.

In the ink supply path, the ink 7 in the ink container 11 is pressurized by the ink supply pump 22 through the ink supply electromagnetic valve 31, adjusted to a predetermined pressure by the pressure regulating valve 10, and passed through the ink ejection electromagnetic valve 33. It is supplied to the recording nozzle 2. An electrostrictive element is provided inside the recording nozzle 2, and ink ejected by the vibration of the present electrostrictive element becomes ink particles. The ink particles are selectively charged by the charging electrode 3, and the charged ink particles are deflected by the deflection electric field generated by the deflection electrode 4 to print characters and symbols on the printing target 6. On the other hand, the uncharged ink particles go straight and are caught by the gutter 5, and are collected by the collection solenoid valve 34 and the negative pressure pump 2.
3 and is returned to the ink container 11 again.

Next, the ink physical property adjustment path will be described. This route has three operations. First, when a large number of printings are performed and the amount of ink in the ink container 11 decreases, the electromagnetic valve is switched so that ink is supplied to the recording nozzle 2 from the sub-ink container 12 (ink supply electromagnetic valve 31:
(Open → closed, sub ink supply solenoid valve 32: closed → open) This is an operation of replenishing the ink container 11 with the sub ink 8 via the recording nozzle 2. The second is an operation of periodically replenishing the ink 7 with the same amount of solvent as the solvent in the ink 7 evaporated during the flight of the ink particles. During this operation, the solvent supply pump 21
And the solvent supply solenoid valve 36 is operated to operate the solvent 9 in the solvent container 13.
To the ink container 11. The third is to forcibly feed the solvent 9 to the recording nozzle 2 to clean the inside of the recording nozzle 2, and the solvent supply pump 21 and the solvent ejection solenoid valve 37 operate. A piping system capable of performing each of the above operations is configured.

Finally, the ink circulation path will be described.
As shown in FIG. 2, the recording nozzle 2 used in the charge control type ink jet recording apparatus is composed of a number of components such as an electrostrictive element 41, a resonator 42, a body 43, and an orifice plate 44 having an ink ejection port 44a. You. There are many voids inside and it has a complicated structure, so it can be said that the air that has entered once is difficult to escape. As described above, since the residual air in the recording nozzle has an adverse effect on the formation of ink particles, it is necessary to sufficiently release air when the apparatus is started. For that purpose, it is necessary to flow a large amount of ink from the ink supply port 25 to the ink discharge port 26 and to give a rapid change in the flow velocity. Therefore, a circulation solenoid valve 35 is provided in the ink circulation path, and the opening and closing of the solenoid valve 35 is operated. However, since the ink circulation path merges with the ink recovery path immediately before the negative pressure pump 23, the chamber section 10 is provided immediately before the junction, and the flow rate of the ink entering from the ink circulation path is reduced before the ink circulation path is merged. The piping system has no adverse effect on the environment.

FIGS. 3 and 4 show a specific example of the structure of the chamber section 10. FIG. Both inks enter from the ink inlet 10a into the gap 10b, then collide with the partition wall 10c which is an obstacle to the ink flow, and then flow into the ink outlet 10d. In FIG. 3, the ink inlet 10 a and the ink outlet 10 d are arranged so as to be orthogonal to each other, and in FIG. 4, they are arranged on a straight line. In each case, the ink outlet 10 d is the extreme end point of the internal void portion. Therefore, by fixing the chamber portion to the apparatus so that the ink outlet 10d is at the lowest position, there is no occurrence of an ink pool that cannot be circulated in the chamber.

By providing the above-described chamber section with a piping system provided in the ink circulation path, when the ink in the recording nozzle is circulated for air bleeding at the time of starting the apparatus, the ink path from the ink circulation path to the recovery path is established. The flow velocity of the ink flowing into the junction can be reduced.

[0016]

According to the present invention, by arranging the chamber in a piping system provided in the ink circulation path, when the ink in the recording nozzle is circulated for air bleeding at the time of starting the apparatus, the junction from the ink circulation path to the collection path. Since the flow rate of the ink flowing into the printer can be reduced, the recovery path is not adversely affected, and a large amount of ink can be flowed, so that the operation preparation time required at the time of starting the apparatus can be shortened, and the handleability of the ink jet recording apparatus is improved. .

[Brief description of the drawings]

FIG. 1 is a system diagram of an ink jet recording apparatus according to the present invention.

FIG. 2 is a sectional view of a recording nozzle of the inkjet recording apparatus.

FIG. 3 is an explanatory view of a structural example of a chamber section according to the present invention.

FIG. 4 is an explanatory view of a structural example of a chamber section according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Chamber part, 2 ... Recording nozzle, 3 ... Charging electrode, 4 ...
Deflection electrode, 5: gutter, 6: printing object, 10: pressure regulating valve,
11 ink container, 12 sub-ink container, 13 solvent container, 21 solvent supply pump, 22 ink supply pump, 23 negative pressure pump, 31 ink supply solenoid valve, 35
... Circulation solenoid valve.

Claims (3)

[Claims] A supply path for supplying the ink in the ink container to a recording nozzle from which the ink particles are ejected; and a recovery path for capturing the ink particles not used for recording by a gutter and returning the ink particles to the ink container. The charge control type ink jet recording apparatus, comprising: a circulation path serving as a path for bleeding air from the recording nozzle when the apparatus is started; and an ink property adjusting path for replenishing the ink container with new ink or ink solvent. And a circulation path near the junction of the circulation path and a chamber section in which a partition wall obstructing the ink flow direction is formed. 2. A piping system for an ink jet recording apparatus according to claim 1, wherein said chamber section is formed at an angle such that an ink inlet and an ink outlet are linear or intersecting with each other. 3. The piping system of an ink jet recording apparatus according to claim 1, wherein the ink outlet of the chamber portion is formed at a lowermost position when the chamber portion is fixed in the apparatus. .