JPS58199162A - Ink droplet jet apparatus - Google Patents

Abstract

PURPOSE:To obtain printing in a high resolving degree, by discharging an ink filling an air layer through a third orifice provided so as to be parted from a first and a second orifices when printing operation is not carried out to prevent the clogging of the orifices. CONSTITUTION:In a home position, a second orifice 6 is under a lid closed state by a lid body 7 and an air layer 5 is filled with an ink to prevent the clogging of a first orifice 4. In this state, the air layer 5 is communicated with an air pump and a solenoid valve 13 is opened to operate the air pump. By this operation, the ink filling the air layer 5 is discharged to the outside from a third orifice 12 pressurized by the air stream 14 shown by an arrow through the solenoid valve 13 under an open state. Because the third orifice 12 is provided so as to be parted from the first and the second orifices 4, 6, the air stream 14 added from the air pump is parallelly flowed along the wall surface of the first orifice and the flowing direction thereof is not abruptly altered even in the vicinity of the first orifice 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink drop ejecting device that prevents clogging of an orifice through which ink is ejected.

It is widely known that the greatest drawback in ink droplet ejection devices is clogging of the orifice through which the ink droplets are ejected. In particular, in an on-demand type ink droplet ejecting device that ejects ink droplets by applying a minute pressure change to the ink near the orifice, the ink droplet is ejected by a minute pressurizing force like a recirculation. When clogging occurs, the 1M clogging cannot be easily recovered by itself, and therefore, it is necessary to prevent clogging in advance during non-printing operations.

On the other hand, for the purpose of assisting the ejection operation of ink droplets, an orifice of WI2 is provided to sandwich air 1IiI in the axial direction of the first stopper from which ink droplets are ejected, and pressure is applied from the outer periphery of the @C air layer. An ink drop ejecting device to which an air flow is added is disclosed in Japanese Patent Laid-Open No. 109758/1983.

The present applicant has filed a patent application for a clogging prevention method suitable for an ink drop ejecting Vita having an air layer in the direction of the first orifice as disclosed in Japanese Patent Application Laid-Open No. 51-169758. The application has been filed as No. 112727, etc. Figure 181 shows the state of the ink droplet ejecting device proposed in the above-mentioned Japanese Patent Application No. 112727/1983 during ink filling operation. il+ is an on-demand diaphragm type ink droplet ejecting device, In addition to the width of the small diameter diaphragm (31!),
The ink on the surface 11U is pressurized to eject ink droplets from the first orifice (4). Then, the ink droplets are ejected from the orifice 182 (6) provided on the axis of the orifice 181 (4) while being blown away by the air flow added from the direction outside the air layer +51. Furthermore, J.
The explanation above is for the printing operation, and there is a difference between it and the 115th non-printing operation. That is.

During non-printing operation, the second orifice (6) is connected to the fish body (
7) causes the air space (5) to be supplied with ink from the first orifice (4), so that the orifice (4) of the trench 1 is covered with the ink. Therefore, the ink filled in the air layer (51) prevents the orifice (4) of the ill from drying out and clogging mainly due to the adhesion of dust.

In FIG. 1, (8) is a replaceable ink cartridge (91 is an air pump that adds air flow to the air layer (51) of the cartridge (8) and the ink droplet ejecting device (1); A three-way solenoid valve installed in the flow path leading to the air layer (51) of the air pump (9) opens the air layer (5) to the outside as shown in the figure during ink filling during non-printing operation. Close the air supply end of the
°Rotate to close the air layer (5) that was open to the outside and drain the filled ink ('rarrtce-1)
It is held by the principle of t1), and the air pump holder and the air layer (5) are communicated with each other during the printing operation.

However, due to such ink filling, the orifice of Yuu 1 (41
Ink droplet ejecting device (11) that prevents clogging in
In this case, the filled ink must be discharged prior to the printing operation.

Therefore, in the past, the three-way solenoid valve 0e was operated to pump air pump +91 and air! In this state, the air pump 19+ is operated to pressurize the filled ink from the #l edge and the second hole opened from the center.
The liquid was discharged to the outside through the orifice (6).

However, in the case where the ink is discharged from the second orifice (6) as shown in FIG. It may cause the wall surface σ11 to become contaminated or the first orifice (4
) It has also been confirmed that ink remains in the vicinity as well by forming the orifice wall of 182 with a transparent material. J Self-Essay 2 - Although dripping of ID ink can be dealt with by wiping it off with an appropriate cleaning device, the cleaning device becomes very dirty and the cleaning device must be used frequently. Must be replaced or cleaned.

On the other hand, there is no appropriate countermeasure for the residual ink near the orifice 147 of @1. This residual ink is caused by the air flow flowing toward the center from the circumference of the air layer t5+ colliding near the first orifice (41), causing the flow to flow toward the second orifice (6). This is due to the bending in the right angle direction.

11!181 orifices (4
), the air flow does not become an axial flow and is discharged without leaving the filled ink in order to form an air 'tA'.
It is not possible to do so. The remainder of this ink is printed @
This may cause non-uniform ejection of ink droplets, generation of afterjet, or undesirable sight lines.

Furthermore, the remaining ink and the dripping of the ink on the second orifice wall surface (Ill) are affected by the viscosity of the ink. If a cylindrical ink with a viscosity of, for example, 4 to 5 cps at room temperature is used to obtain the same, this effect will be significant.

The present invention has been accomplished in this respect.

An embodiment of the present invention will be described in detail with reference to FIGS. 4 and 5.

Figure '@4 is a Tl1i plane view showing an embodiment of the present invention, and the same parts as the conventional example shown in Figure '@1 are omitted with reference to station numbers and explanations. That is, one feature of the present invention is that the first and 182nd orifices +41 are opposed to each other with the air layer (5) in between.
A sixth orifice a' which communicates to the outside with the central air-(5) station line separated from (6);! Along with establishing J.

This is where a normally closed solenoid valve a3 is connected which opens and closes the orifice α2 of II5. During the non-printing operation, the ink filled in the air layer (51) is discharged from the orifice α2 of @I!21B5 by the opening operation of the solenoid valve α3.

The discharge operation of the filled ink will be explained with reference to FIG. 4 and FIG. 5, which shows an enlarged view of the main part.

In the home position, the second orifice (6) is in a ghost state due to the placement body (7), and the air space (5) is filled with ink to prevent the orifice 181 (41) from clogging. In this state, the air layer +51 and the air pump (9) are made to communicate with each other, and the solenoid valve (13) is opened to operate the air pump (9)%.
The ink filled in 51 flows through the air flow r14 as shown by the arrow.
The solenoid valve α3M which is pressurized by 1 and opened from the third orifice C13! :Expelled to the outside through. The fifth orifice α3 is provided at a distance of 11!1 from the second orifice (4)+61, and the air flow a4 added from the air pump (9) flows through the orifice wall surface (151 The filling ink flows in parallel along the orifice (4) of @1, but the flow direction does not suddenly change even near the orifice (4) of the filling ink.
Even in the vicinity of the first orifice (4), the air flow I becomes a uniform flow as shown in FIG. After the discharge is completed, the solenoid valve a3 closes and substantially closes the third orifice a2, resulting in a standby state.

In addition, the ejection operation of the first filling ink @? The second orifice (
There is a risk that ink may remain in the second orifice (6), but in order to prevent ink from remaining in the second orifice (6), the shape of the second orifice (6) should be changed, for example, by changing the shape of the air layer (
5) This can be dealt with by machining it into a funnel shape with a larger diameter on the side. Furthermore, even if the ink remains without being processed into a funnel shape, only the air flow α is added prior to the printing operation. Since the residual ink can also be ejected to the outside, the residual ink in the 1 lB2 orifice (6) does not pose an acid root problem.

As is clear from the above description, the present invention provides a sixth orifice separately from the two orifices 18 and 182 facing each other with an air layer in between;
Since the ink filled in the air layer during non-printing operation is discharged through this orifice, ink will not remain near the orifice @1, and ink will not drip from the second orifice. do not have. Therefore, good ink droplets can be ejected during the printing operation, and since there is a risk that ink may remain in the vicinity of the @1 orifice or ink may drip from the second orifice if a conventional knife is used. This makes it possible to use high-viscosity ink, which has been limited in use, and allows high-resolution printing to be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the ink filling operation of a conventional ink control jetting device, FIG. 2 is a front view showing the conventional ink discharging operation, and FIG. 6 is an enlarged cross-sectional view of the inner part thereof. FIG. 4 is a sectional view showing the ink ejecting operation of the ink droplet ejecting device of the present invention, and FIG. W15 is an enlarged sectional view of the ink droplet ejecting device. 11J...Ink droplet ejecting device, (4)...Wll orifice. (5)...Air layer, (6th...11!2 orifice%0...6th orifice, (13...Solenoid valve.

Claims (1)

[Claims] (1) First and second orifices Yl facing each other with air WI in between! In the ink droplet ejecting device that closes the second orifice set out in the table fil during non-printing operation, fills the air layer with ink and covers the first orifice with the ink, the printing is performed. Prior to the printing operation, the ink that has been filled for a period of time is discharged from an orifice 183 provided apart from the first and second orifices, and during the printing operation, this fifth orifice is substantially closed. An ink droplet ejecting device characterized by: