JP7233897B2 - Inkjet recording device - Google Patents

Description

The present invention relates to an inkjet recording apparatus.

Among inkjet recording devices, continuous ejection type inkjet devices are highly stable droplet ejection devices with high reliability and high maintainability compared to on-demand type inkjet devices used in home or office printers. be.

In most of the continuous ejection type ink jet recording apparatuses, a gutter for collecting non-charged particles that are not used for printing is installed in front of the printed material. In order to collect the ink droplets, the gutter uses a pump installed downstream to suck the air around the gutter. Due to the effect of this suction air, the ink droplet particles that have entered the gutter are efficiently recovered.

However, some of the ink droplet particles that have entered the gutter are scattered when they collide with the inlet of the gutter. The scattered droplets accumulate at the inlet of the gutter as the apparatus is operated, and grow into a liquid film or large ink droplets. As a result, the droplets for printing come into contact with the liquid film or droplets deposited at the gutter entrance, which causes poor printing or clogging of the gutter.

Therefore, as disclosed in Japanese Unexamined Patent Application Publication No. 2002-100001, by forming a ring of different diameters in the circumferential direction on the inner wall of the means for collecting the unnecessary ink droplets, the unnecessary ink droplets are formed on the inner wall of the means for collecting the unnecessary ink droplets in the circumferential direction. It is disclosed that the ink spreads out and generally flows as a slug flow, increasing ink recovery.

JP 2017-74712 A

The technique of Patent Document 1 is effective for collecting ink droplet particles inside the gutter, but does not consider collecting the ink liquid film or ink droplets deposited at the gutter inlet. .

Therefore, it is necessary to prevent the ink liquid film and ink droplets from depositing on the gutter inlet. For this purpose, it is necessary to move the ink liquid film and ink droplets deposited at the gutter entrance into the inside of the gutter.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce ink droplets or ink film build-up at the entrance of the gutter.

A preferred example of the present invention includes a charging electrode that charges ink droplets, a deflection electrode that generates an electric field that deflects the flying direction of the charged ink droplets, and a gutter that collects the ink droplets that are not used for printing. , wherein the input portion of the gutter for taking in the ink droplets is provided with a notch.

According to the present invention, it is possible to reduce the amount of ink droplets or ink liquid film deposited at the inlet of the gutter.

1 is a configuration diagram of a main part of a continuous ejection type inkjet recording apparatus of Example 1. FIG. 4 is a view showing radial cutouts at the inlet of the gutter in Example 1. FIG. FIG. 3 is a view of the radial notch of FIG. 2 viewed from the direction in which ink droplet particles fly; In FIG. 2, it is the figure which showed the internal structure of the inlet part of a gutter. FIG. 10 is a configuration diagram of a continuous ejection type inkjet recording apparatus in Example 2; FIG. 11 is a configuration diagram of a continuous ejection type inkjet recording apparatus in Example 3; FIG. 11 is a configuration diagram of a continuous ejection type inkjet recording apparatus in Example 4; FIG. 11 is a configuration diagram of a continuous ejection type inkjet recording apparatus in Example 5; It is a figure explaining the mechanism by which an ink droplet moves inside a gutter cylinder.

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

1 to 3 and 9, the configuration of a continuous ejection type ink jet recording apparatus (or continuous ink jet apparatus) in Example 1 will be described.

In FIG. 1, the inkjet head of the continuous ejection type inkjet recording apparatus includes a nozzle head 102 having an ink chamber 101 for ejecting ink droplets, a charging electrode 103 for individually charging the formed ink droplets, and a charging electrode. 108, a pair of deflection electrodes 105 and 111 for deflecting charged ink droplets by an electric field, and a gutter 113 for collecting ink droplets not used for printing to reuse them. It has

The deflection electrodes 105 and 111 are installed so as to have parallel facing surfaces. The ink droplets are printed by landing on the print body 116 .

In the configuration shown in FIG. 1, the liquid column 107 ejected from the nozzles of the nozzle head 102 is cut by vibration applied from the upper part of the ink chamber 101 in the nozzle head 102 to form a droplet array as shown. .

Here, the entire housing of the nozzle head 102 is grounded. The formed ink droplets are formed on the charged electrode substrate 104 and the charged electrode substrate 109, and the charged electrodes 103 and 108 arranged close to each other so as to be parallel to the flight direction of the ink droplets. Negatively charged.

Here, the charging voltage controller 114 applies an arbitrary voltage to the charging electrode 103 at arbitrary timing. As a result, the charging electrodes 103 and 108 will apply any voltage to the ink droplets at any timing, thereby charging the individual ink droplets in accordance with the desired print form. It is configured so that

At this time, the breaking points of the liquid column 107 (the ink droplets are formed by cutting the liquid column) are positioned on the charging electrodes 103 and 108 provided corresponding to the ink droplet row. It is designed to Moreover, the charging electrodes 103 and 108 are preferably arranged so that the ink droplet row passes through the vicinity of the center in the width direction (the direction perpendicular to the paper surface of the drawing).

Here, a deflection electric field for deflecting the ink droplets 112 charged by the electric field in an arbitrary direction is formed below the ink flying direction (below the charging electrode 103 and the charging electrode 108) in the charging process. Deflection electrodes are installed.

These deflection electrodes are composed of a ground deflection electrode 105 (first deflection electrode) and a high-voltage deflection electrode 111 (second deflection electrode), which are arranged in parallel and face each other. are perpendicular to the ground deflection electrode plane 105 and the high voltage deflection electrode plane 111 and are formed parallel to each other.

A deflection electric field is formed between the ground deflection electrode 105 and the high voltage deflection electrode 111 by the voltage applied to the high voltage deflection electrode 111 from the deflection voltage controller 115 . Ink droplets (including charged ink droplets and uncharged ink droplets) after passing through the charging electrodes 103 and 108 fly within the region in which the deflection electric field is formed. Then, the charged ink droplet 112 is deflected in a direction opposite to the charge sign to approach the electrode 111 by the influence of the deflection electric field, and lands on the print body 116 to form a print pattern.

Since the highly charged ink droplets approach the high voltage deflection electrode surface 111, which is the positive side electrode, the ink incident line 101' is set at a position close to the surface of the ground deflection electrode 105 in order to print large characters. be.

The flight of these particles also induces an air current 120 between the ground deflection electrode 105 and the high voltage deflection electrode 111 . At this time, the non-charged particles fly along this linear ink incident line 101' and enter the gutter 113 that collects the ink droplets. Although not shown, downstream of the gutter 113, there are provided a pump for sucking ink droplets for collection, an ink container for storing ink such as the collected ink droplets, and the like.

Details of the first embodiment will be described with reference to FIG. The inlet of the gutter 113, which takes in ink droplets, is around the tip of the cylindrical gutter 113, and is provided with radial cutouts 201. As shown in FIG. Although four cutouts are provided in FIG. 2, the number of cutouts 201 is not limited to this embodiment.

FIG. 3 is a view of the radial notch 201 provided at the entrance of the gutter, viewed from the incident direction 204 in which the ink droplet particles of FIG. 2 fly. A groove 203 is provided in the inner wall of the inlet of the gutter in the direction of the central axis of the cylinder, and the radial notch 201 communicates with the groove 203 .

FIG. 4 is a diagram showing the internal structure of the inlet of the gutter 113 (illustrated by dotted lines). The cross-sectional area of the radial notch 201 provided at the inlet of the gutter 113 decreases from the outer circumference of the cylinder toward the inner circumference of the cylinder. A groove 203 formed in the inner wall portion of the inlet portion of the gutter 113 in the direction of the central axis of the cylinder is indicated by a dotted line.

FIG. 9 illustrates the mechanism by which an ink droplet 901 flying to the inlet of the gutter 113 moves inside the cylinder of the gutter 113 . A pump is installed on the downstream side of the gutter 113 and sucks the air around the gutter exit in the direction of arrow 904 . As a result, air currents as indicated by arrows 905 , 906 and 907 are generated around the entrance of the gutter 113 .

Due to the air drag of this airflow, the ink droplets 902 deposited at the inlet of the gutter 113 move to the notch 201 and enter the groove in the direction of the central axis of the cylinder provided on the inner wall of the inlet of the gutter 113. It moves downstream of the gutter 113 .

A feature of this embodiment is that the ink droplets or liquid film deposited at the inlet of the gutter 113 can be moved into the gutter 113 even when no air current is generated by the pump. As shown in FIGS. 2 and 3, a structure in which the cross-sectional area of the radial notch 201 provided at the entrance of the gutter 113 decreases from the outer circumference of the cylinder toward the inner circumference of the cylinder (the surface 202 of the cylinder is tapered). It has become.

Due to the meniscus effect of the surface tension generated by this configuration, it is possible to move the ink droplets 902 and the liquid film around the notch 201 into the cylinder. An ink droplet or liquid film passing through the notch 201 has a mechanism of wetting and spreading into the groove 203 .

The configuration of the continuous ejection type inkjet recording apparatus according to the second embodiment will be described with reference to FIG. In the second embodiment, the gutter 113 is formed so that the cross-sectional area of the radial notch 201 provided at the inlet of the gutter 113 becomes smaller in the ink droplet collection direction, which is the direction toward the ink container that stores the ink. The notch 201 has a tapered shape 501 .

By forming the tapered shape 501 , the flow velocity of the air sucked by the pump becomes faster in the downstream direction of the notch 201 , and ink droplets and liquid films deposited at the inlet of the gutter 113 are more efficiently removed from the gutter 113 . You can move inside.

The configuration of the continuous ejection type inkjet recording apparatus according to the third embodiment will be described with reference to FIG. The third embodiment is characterized in that a groove 601 is provided in the circumferential direction of the cylinder on the outer peripheral surface of the inlet of the gutter 113 and the groove 601 communicates with the radial notch 201 .

The ink droplets or liquid film deposited on the outer peripheral surface of the inlet of the gutter 113 soaks into the groove 601 due to the meniscus effect and moves to the notch 201 . Therefore, it is possible to efficiently move the ink droplets or the liquid film adhering to a place away from the notch 201 to the notch 201 .

The configuration of the continuous ejection type inkjet recording apparatus according to the fourth embodiment will be described with reference to FIG. The fourth embodiment is characterized in that a ring 701 is provided upstream of the radial notch 201 provided at the entrance of the gutter 113 , that is, in the direction of the tip of the gutter 113 . By adopting this configuration, it is possible to reduce the scattering of ink droplets when they land on the edge portion of the notch portion 201 .

The configuration of the continuous ejection type inkjet recording apparatus according to the fifth embodiment will be described with reference to FIG. In Example 5, the part including the radial notch 201 and the grooves in the cylindrical circumferential direction on the outer peripheral surface is made into a separate member 801, which can be attached to the entrance of the existing gutter or can be removed for maintenance.

In the configuration of FIG. 8, the inner diameter of the inlet portion of the gutter 113 to which the gutter 113 is attached is larger than the inner diameter of the separate member. Also, 802 indicates the groove in the direction of the central axis of the cylinder, and 803 indicates the inner wall surface of the gutter.

According to the fifth embodiment, by minimizing the structural change of the current model, it becomes possible to collect ink droplets and liquid films deposited at the inlet of the gutter 113 inside the gutter.

If the structure is such that ink droplets and liquid films are smoothly collected from the separate member into the existing gutter, the inner diameter of the separate member and the inner diameter of the inlet of the gutter 113 to which it is attached should be substantially the same. I don't mind. Alternatively, the inner diameter of the separate member of the gutter 113 may be made larger than the inner diameter of the inlet portion of the gutter 113 to which it is attached, so as to prevent the ink droplets from scattering toward the print body.

113 gutter, 201 notch, 202 tapered surface of notch, 203 groove in the central axis direction of the cylinder, 601 groove in the circumferential direction of the cylinder, 701 ring

Claims (7)

a charging electrode for charging the ink droplets;
a deflection electrode that generates an electric field that deflects the flight direction of the charged ink droplets;
An inkjet recording apparatus having a gutter for collecting the ink droplets not used for printing,
A notch is provided at the inlet of the gutter that takes in the ink droplets ,
A groove is arranged in the central axis direction of the inner wall of the gutter,
An inkjet recording apparatus , wherein the notch and the groove communicate with each other . a charging electrode for charging the ink droplets;
a deflection electrode that generates an electric field that deflects the flight direction of the charged ink droplets;
An inkjet recording apparatus having a gutter for collecting the ink droplets not used for printing,
A notch is provided at the inlet of the gutter that takes in the ink droplets ,
Having a groove in the circumferential direction of the cylinder on the outer peripheral surface of the gutter,
An inkjet recording apparatus , wherein the groove communicates with the notch . a charging electrode for charging the ink droplets;
a deflection electrode that generates an electric field that deflects the flight direction of the charged ink droplets;
An inkjet recording apparatus having a gutter for collecting the ink droplets not used for printing,
A notch is provided at the inlet of the gutter that takes in the ink droplets ,
An inkjet recording apparatus, wherein a ring is provided in the tip direction of the notch . In the inkjet recording apparatus according to any one of claims 1 to 3 ,
An ink jet recording apparatus, wherein the cross-sectional area of the notch portion decreases in the collecting direction of the ink droplets. In the inkjet recording apparatus according to any one of claims 1 to 3 ,
The entrance portion of the gutter having the notch includes:
An ink jet recording apparatus characterized by being mountable. In the inkjet recording apparatus according to any one of claims 1 to 3 ,
An inkjet recording apparatus, comprising an ink droplet ejection section for ejecting the ink droplets toward the charging electrode. In the inkjet recording apparatus according to any one of claims 1 to 3 ,
a pump that sucks the ink droplets taken in from the gutter;
and an ink container for storing the ink droplets.

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