JPH0569552A - Preventing device for clogging of ink jet head - Google Patents

Abstract

PURPOSE:To prevent ink outlet ports from clogging with ink by making a simple structure without requiring any caps and thereby provide an inexpensive device for preventing the clogging of an ink jet head. CONSTITUTION:After printing is finished, an orifice plate 2 and a head main body 3 are moved relative to each other by means of a relative movement mechanism consisting of a drive gear 10, a drive shaft 9 and a semicircular cam 11. Thereby, each of a plurality of ink chambers 12 formed in the head main body 3 becomes uncommuicated with each of ink outlet ports 6 bored in the orifice plate 2 so as to communicate with each ink chamber 12. As a result, ink L in each ink chamber 12 is not exposed to the external air through the ink outlet port 6 when printing is not done and, accordingly, evaporation of solvent components of the ink L in the ink chambers 12 is prevented, so that a viscosity of the ink L can be kept constant without being changed. Therefore, the clogging of the ink outlet ports 6 due to ink can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head clogging prevention device, and more particularly to an ink jet caused by drying of ink by releasing communication between the ink chamber of the head body and the ink discharge port of the orifice plate. The present invention relates to a device for preventing clogging of an inkjet head that prevents clogging.

[0002]

2. Description of the Related Art Conventionally, various printers have been proposed as a printing device, and these printers are roughly classified into two types of printers due to the difference in printing method. One of them is an impact-type printer typified by a wire dot printer. Since this printer is a method of hitting a wire on a printing paper via a printing ribbon or the like to perform printing, noise generated during printing is a problem. Was becoming.

The other one is a non-impact printer represented by an ink jet printer which performs printing by a printing method such as a bubble jet method using an electrothermal conversion element and a piezoelectric method using an electromechanical conversion element. Printers have been attracting more and more attention in recent years because of lower noise during printing than the impact printers.

An ink jet head in such an ink jet printer is generally provided with a head body having a plurality of ink chambers formed therein and an orifice plate having an ink discharge port communicating with each ink chamber, and the electrothermal conversion. An element or an electromechanical conversion element is used to increase the internal pressure of the ink chamber to eject ink droplets from the ink ejection port to perform printing.

In such an ink jet head,
At the time of non-printing, the solvent component of the ink in the ink chamber evaporates through the ink ejection port that comes into contact with the outside air, and as a result,
The ink component changes. Since the viscosity of the ink becomes higher than this, the ink is likely to be clogged at the ink ejection port, and there is a possibility that normal printing cannot be performed at the time of reprinting.

Under these circumstances, various clogging prevention devices have been proposed for conventional ink jet heads, and are described, for example, in Japanese Patent Publication No. 63-62395 and Japanese Patent Publication No. 1-18866. As described above, there is proposed a device for preventing clogging by providing a cap covering the ink ejection port in order to avoid drying of the ink in the ink ejection port during non-printing.

[0007]

However, in the above-mentioned conventional clogging prevention device, a cap for covering the ink ejection port is required, and during printing, the cap is moved to the retracted position separated from the ink ejection port. In order to do so, a complicated cap moving mechanism is required. As a result, the number of components increases and the structure becomes complicated, resulting in an increase in the cost of the device.

The present invention has been made in order to solve the above-mentioned problems of the prior art, since the viscosity of the ink increases as the solvent component of the ink evaporates with a simple structure without the need for a cap. It is an object of the present invention to provide a device for preventing clogging of an ink jet head, which can prevent clogging of ink at an ink ejection port that occurs and is low in cost.

[0009]

In order to achieve this object, an ink-jet head clogging prevention device of the present invention comprises:
A head main body in which a plurality of partially open ink chambers are formed with a predetermined pitch, and a plurality of ink ejection ports that communicate with each of the ink chambers are formed with the same pitch as the predetermined pitch. A relative member that relatively moves the orifice plate disposed so as to close the opening and the head body and the orifice plate to release communication between each ink chamber of the head body and each ink ejection port of the orifice plate. And a moving mechanism.

Further, the relative movement mechanism connects the head body and the orifice plate to 1/2 of the predetermined pitch.
It is configured to move relative to the pitch.

[0011]

In the ink jet head clogging prevention device according to the present invention having the above-described structure, the orifice plate and the head body are relatively moved via the relative movement mechanism at the time of non-printing after the completion of printing. As a result, the communication between the plurality of ink chambers formed in the head main body and the ink ejection ports formed in the orifice plate so as to communicate with the respective ink chambers is released.

As a result, the ink in each ink chamber does not come into contact with the outside air through the ink ejection port during non-printing, so that the solvent component of the ink in the ink chamber is prevented from evaporating and the viscosity of the ink changes. Instead, the ink is held constant and the clogging of the ink at the ink ejection port is prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the drawings. FIG. 1 is an enlarged schematic perspective view of an inkjet head according to the present embodiment. The inkjet head 1 includes an orifice plate 2, a head body 3, and a pair of guide plates 4 fixed to both side surfaces of the orifice plate 2. (Only one is shown in Fig. 1)
And a support plate 5 for guiding and supporting the head body 3 on the lower surface of the head body 3.

The orifice plate 2 is provided with a plurality of ink discharge ports 6 at a constant pitch, and a pair of guide plates 4 are provided on both side surfaces of the orifice plate 2.
The upper ends of the are fixed. At the rear end (left end in FIG. 1) of each guide plate 4, there is a leaf spring member 7 (only one shown in the figure) for restricting movement of the head body 3 described later in the rearward direction (leftward in FIG. 1). ) Is stuck.

The front of each guide plate 4 (rightward in FIG. 1)
The shaft hole 8 is provided in the shaft hole 8, and the drive shaft 9 is inserted into the shaft hole 8. The drive gear 1 is provided at one end of the drive shaft 9.
0 is fixed, and the drive gear 10 is rotationally driven by a drive motor (not shown). Further, a half-moon cam 11 is fixed to an intermediate portion of the drive shaft 9, and the half-moon cam 11 is fixed.
Is integrally rotated by the rotation of the drive shaft 9 to move the head main body 3 described later relative to the orifice plate 2 in the arrow A direction. Further, a support plate 5 is fixed to the lower end portions of both guide plates 4, and the support plate 5 guides and supports the head main body 3 moved by the meniscus cam 11.

A head body 3 is arranged between the orifice plate 2 and the support plate 5 so as to be movable relative to the two orifice plates 2 and the support plate 5. As shown in FIGS. 2 and 3, the head body 3 is provided with a plurality of ink chambers 12 at the same pitch as the pitch of the ink ejection ports 6 formed in the orifice plate 2.
The ink L is filled in each ink chamber 12. Also,
The open side of each ink chamber 12 is the orifice plate 2
As a result, the ink ejection ports 6 are communicated with the respective ink chambers 12 as shown in FIG.

Piezoelectric elements 13 are fixed to the lower surface of the head main body 3 so as to correspond to the ink chambers 12. The piezoelectric elements 13 are selectively driven to increase the internal pressure of the ink chambers 12. Ink droplets of the ink L are ejected from the ink ejection port 6 to print desired characters or the like on a print sheet (not shown).

Next, the operation for preventing ink clogging in the ink jet head 1 thus constructed will be described with reference to FIGS. 4 and 5.

In FIG. 4, when the drive shaft 9 is rotated in the direction of arrow B via a drive motor (not shown) and the drive gear 10 during non-printing after printing is completed, the half-moon cam 1
1 is also rotated in the same direction, and accordingly, the head body 3 is guided by the support plate 5 and moved in the direction of arrow A relative to the orifice plate 2.

Here, the meniscus cam 11 is such that when the meniscus cam 11 is rotated 180 degrees from the state shown in FIG. 1 (the state shown in FIG. 5), the head main body 3 has a pitch of the ink ejection ports 6 (pitch of the ink chamber 12). The radius is determined so as to move 1/2 of (equal to). Therefore, at this time, the state shown in FIG. 5 is established, and the communication between the ink ejection ports 6 and the ink chambers 12 is released.

Since the leaf spring member 7 is fixed to the head main body 3 as described above, the head main body 3 is always biased in the direction opposite to the arrow A direction. The head body 3 does not overshoot in the direction of the arrow A even when relatively moved by the meniscus cam 11, so that the head body 3 is at a position where the communication between the ink ejection port 6 and the ink chamber 12 is released. Securely locked by 7.

As a result, the ink L in the ink chamber 12 is
Is no longer in contact with the outside air via the ink discharge port 6,
As a result, it is possible to prevent the solvent component of the ink L in the ink chamber 12 from evaporating and increasing the viscosity of the ink L. Therefore, it is possible to reliably prevent the clogging of the ink L.

On the other hand, when the printing is restarted, the drive motor (not shown), the drive gear 10, the drive shaft 9 are reversed, contrary to the above.
The half-moon cam 11 is rotated in the direction opposite to the arrow B direction via. As a result, the head body 3 relatively moves in the direction opposite to the arrow A direction by 1/2 pitch, and as a result, the ink ejection ports 6 and the ink chambers 12 communicate with each other, as shown in FIG. In that case, printing can be restarted.

As described in detail above, in the ink jet head clogging prevention device according to this embodiment, the ink chamber 12 of the head main body 3 and the ink discharge port 6 of the orifice plate 2 are formed at the same pitch, and the drive shaft is Since the head main body 3 is moved relative to the orifice plate 2 through the half-moon cam 11 fixed to 9 to release the communication between the ink chamber 12 and the ink ejection port 6, it is possible to use the conventional device. A cap and a complicated moving mechanism for moving the cap can be omitted.

Therefore, the ink discharge port 6 has a simple structure.
It is possible to provide a low-cost clogging prevention device that can reliably prevent the clogging of the ink. In this embodiment, the head body 3 is connected to the pair of guide plates 4.
Although the guide is performed by the cooperation of the support plate 5 and the support plate 5, the present invention is not limited to this, and various modifications and improvements can be made without departing from the spirit of the present invention.

For example, as shown in FIG. 6, a guide groove 14 having orifice plates 2 formed on both sides of the head body 3 is formed.
You may be guided by. In addition, as shown in FIG. 7, the edge portion 15 of the lid body 15 that covers the upper surface of the head body 3
The lid body 15 is fixed to the head body 3 so that A extends from the head body 3, and an extension portion 3A is also provided in the lower portion of the head body 3, and the end extension portion 15A and the extension portion 3A guide The portion C may be configured so that the orifice plate 2 is slidably guided through the guide portion C.

[0027]

As described above, according to the present invention, the clogging of the ink at the ink ejection port, which is caused by the increase in the viscosity of the ink as the solvent component of the ink evaporates with a simple structure without the need for a cap, is described. It is possible to provide a device for preventing clogging of an inkjet head, which can prevent the clogging of the inkjet head, and the industrial effect thereof is great.

[Brief description of drawings]

FIG. 1 is an enlarged schematic perspective view of an inkjet head.

FIG. 2 is a sectional view of a main part of an inkjet head.

FIG. 3 is an exploded explanatory view of a main part of the inkjet head.

FIG. 4 is an enlarged schematic perspective view of an inkjet head showing a state where an orifice plate and a head body are relatively moved.

FIG. 5 is a cross-sectional view showing a state where the orifice plate and the head main body are relatively moved.

FIG. 6 is an explanatory view showing another method of relatively moving the orifice plate and the head main body.

FIG. 7 is an explanatory diagram showing still another method of relatively moving the orifice plate and the head main body.

[Explanation of symbols]

 1 Inkjet Head 2 Orifice Plate 3 Head Body 6 Ink Discharge Port 9 Drive Shaft 10 Drive Gear 11 Half Moon Cam 12 Ink Chamber

Claims (2)

[Claims] 1. A head main body in which a plurality of ink chambers, which are partially opened, are formed with a predetermined pitch, and a plurality of ink ejection ports communicating with each of the ink chambers are formed with the same pitch as the predetermined pitch. An orifice plate disposed so as to close the open portion of each ink chamber, and the head main body and the orifice plate are moved relative to each other so that each ink chamber of the head main body and each ink ejection port of the orifice plate A device for preventing clogging of an inkjet head, comprising: a relative movement mechanism that releases communication. 2. The apparatus for preventing clogging of an inkjet head according to claim 1, wherein the relative movement mechanism is configured to relatively move the head body and the orifice plate by 1/2 pitch of the predetermined pitch. ..