JP3781284B2 - Inkjet recording head and recording apparatus therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording head that performs recording by discharging ink jet ink onto a transported recording paper and an apparatus thereof, and in particular, prevents adhesion of paper dust, dust, and the like around the nozzle portion of the recording head, and the nozzle portion. This relates to the prevention of drying of the surrounding ink.
[0002]
[Prior art]
In the case of an apparatus that performs ink jet recording on recording paper, it may be caused by ink flying bend or non-ejection caused by adhesion of paper dust or dust around the nozzle part of the recording head or ink thickening around the nozzle part. It is important to eliminate printing defects.
[0003]
Up to now, recording paper with reduced generation of paper dust and ink that is difficult to dry have been developed, but the performance is not sufficient. Therefore, countermeasures on the ink jet recording head and its apparatus side are necessary, and many proposals have been made to prevent adhesion of paper dust and dust to the periphery of the nozzle portion of the recording head and to prevent ink drying of the nozzle portion.
[0004]
For example, in the case of a continuous ink jet recording head that charges ink particles continuously ejected from nozzles and collects ink particles unnecessary for recording, ink is ejected while air is ejected from an air duct provided at the tip of the nozzle. Therefore, there is very little adhesion of paper dust, dust, etc. around the nozzle part. Moreover, since ink is discharged and collected in the air duct, the inside of the air duct can be kept at high humidity, and ink drying around the nozzle portion can be prevented.
[0005]
However, nothing is disclosed about cleanability of thickened ink and dust adhered to the periphery of the nozzle portion covered with the air duct, and so-called workability during maintenance of the recording head.
[0006]
On the other hand, as a countermeasure on the apparatus side, as described in Japanese Patent Laid-Open No. 11-035186, a paper dust suction pipe communicating with a suction fan is disposed in the vicinity of the recording head, or described in Japanese Patent No. 2796719. As described above, proposals have been made to remove paper dust adhering to a paper feed roller with a cleaning tool in which an adhesive layer is formed.
[0007]
[Problems to be solved by the invention]
Printing failure is caused by adhesion of paper dust or dust around the nozzle portion of the recording head, ink flying bend or non-ejection caused by ink thickening around the nozzle portion. Recording paper with reduced generation of paper dust and ink that is difficult to dry have been developed, but the performance is not sufficient.
[0008]
It is possible to dispose the paper dust suction pipe connected to the suction fan near the recording head on the apparatus side, or to remove the paper dust adhering to the paper feed roller with a cleaning tool in which an adhesive layer is formed. There is a limit in terms of removal performance of powder and dust.
[0009]
In addition, as a measure to prevent paper dust and dust from adhering to the periphery of the nozzle section on the recording head side, in the case of a continuous inkjet recording head, ink is ejected while ejecting air from an air duct provided at the nozzle tip. Although it corresponds, there is a big problem in the cleanability around the nozzle part in a narrow area covered with the air duct.
[0010]
An object of the present invention is that there is very little adhesion of paper dust, dust, etc. to the periphery of the nozzle part, ink drying around the nozzle part can be prevented, and thickened ink or paper attached to the periphery of the nozzle part. It is an object of the present invention to provide an ink jet recording head excellent in cleanability of powder, dust and the like and its recording apparatus.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a nozzle plate having a plurality of nozzles arranged in a line at a constant pitch, an air duct provided so as to surround the nozzles of the nozzle plate, and the air duct In an ink jet recording head that discharges ink from the nozzle while sending air from the air duct to the nozzle, movable means that can move relative to the nozzle plate. I made it. In this case, during ink jet recording and recording standby, the air duct is projected from the nozzle forming surface of the nozzle plate to inject air, so that not only paper dust and dust can be prevented from adhering to the periphery of the nozzle, but also head maintenance. Sometimes the air duct moves backward toward the nozzle plate, so that the cleanability of the nozzle plate surface can be improved.
[0012]
Further, since the air duct movable means is provided in conjunction with the recording head or the air duct movable means in conjunction with the retraction operation of the recording head, the air duct can be easily moved.
[0013]
Alternatively, since the air duct is provided with a cap member that caps the nozzle forming surface of the nozzle plate by moving the air duct, it is possible to prevent ink from drying around the nozzle portion.
[0014]
In addition, the air speed and air volume ejected from the air duct during ink jet recording and recording standby are reduced, and the air air speed and air volume are increased during the maintenance operation of the recording head. Ink can be prevented from entering the air duct during the maintenance operation.
[0015]
Alternatively, humidified air is jetted from the air duct during recording and a moisturizing material is provided on the inner wall of the air duct, so that ink drying around the nozzle portion can be prevented.
[0016]
Further, since the air duct is made of ink repellent material or the air duct surface is subjected to ink repellent treatment, ink does not adhere to the air duct.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a partial sectional view showing an ink jet recording head as an example of the present invention.
[0018]
First, the configuration will be described with reference to FIG. 1. 1 is a nozzle plate, 1a is a nozzle arranged in a line at a fixed pitch on the nozzle forming surface 1b of the nozzle plate 1, 2 is an ink chamber, 3 is a filled ink, 4 Is an air duct made of an ink repellent material provided so as to surround the nozzle 1 a of the nozzle plate 1, 4 a is an air ejection hole provided facing the position of the nozzle 1 a, and 5 is a continuous line provided on the inner wall of the air duct 4. Moisturizing material made of foam sponge, 6 is connected to the air duct 4, blower for sending clean air 7 filtered in advance, etc. 8 is a humidifier for humidifying the air 7 sent out from the blower 6, 9 is the air duct 4. Solenoids 10, which are movable means capable of projecting and retreating the nozzle plate 1, are recording sheets.
[0019]
Next, the operation of the recording head during printing will be described with reference to FIG. 1. The filling ink 3 in the ink chamber 2 is caused by the pressure change in the ink chamber 2 due to the displacement of the vibration plate to which a piezoelectric element (not shown) is bonded. The ink droplets 3a from the nozzles 1a land on the recording paper 10 moving at a constant speed. Since the piezoelectric element is driven only when recording is necessary, it is called a drop-on-demand ink jet recording head for the continuous ink jet recording head.
[0020]
The filled ink 3 in the ink chamber 2 is supplied from an ink tank (not shown). The stop position of the air duct 4 with respect to the nozzle plate 1 is held by the solenoid 9 so that the air ejection hole 4a protrudes from the nozzle forming surface 1b. On the other hand, the air 7 indicated by a plurality of arrows is sent out from the blower 6 and is then humidified by the humidifier 8 and is jetted onto the recording paper 10 from the air ejection holes 4a through the air flow paths 4b on both sides of the nozzle 1a. The At this time, the wind speed and the air volume of the air 7 ejected from the air ejection holes 4a are set to be small enough not to cause problems such as bending of the ink droplets 3a.
[0021]
Accordingly, since the ink droplet 3a ejected from the nozzle 1a passes through the air ejection hole 4a together with the humidified air 7, the periphery of the nozzle 1a such as paper dust or dust conveyed by the moving recording paper 10 Entry to the part can be prevented.
[0022]
In addition, since the position of the air duct 4 and the jetting state of the air 7 are the same as those during printing during standby for printing, paper dust and dust are prevented from entering the nozzle 1a and the ink around the nozzle 1a. Drying prevention is possible.
[0023]
Further, since the air duct 4 protrudes from the nozzle plate 1, even if the recording paper 10 is jammed at the nozzle plate 1, the paper dust on the nozzle 1 a due to the recording paper 10 coming into contact with the nozzle plate 1 Adhesion of dust and the like can be avoided. In addition, since there is the moisture retaining material 5 provided on the inner wall of the air duct 4, the humidified state in the air duct 4 is stabilized, and drying around the nozzles 1a can be prevented even when the temperature of the recording paper is high.
[0024]
Next, the operation during recording head maintenance will be described. FIG. 2 is a partial cross-sectional view for explaining the recording head maintenance operation state of the ink jet recording head as an example of the present invention.
[0025]
The position of the air duct 4 with respect to the nozzle plate 1 is held by a solenoid 9 so that the air ejection hole 4a is retracted toward the nozzle forming surface 1b and the air ejection hole 4a is slightly left with respect to the nozzle plate 1. On the other hand, 11 is a recording head maintenance part having an air suction hole 11a facing the position of the air ejection hole 4a, and has a function of sucking air from the air suction hole 11a by having a suction means (not shown). When the recording head maintenance operation is performed, the air suction hole 11a of the recording head maintenance unit 11 is brought into contact with the air suction hole 11a of the air duct 4 by moving means (not shown). Can flow into the air suction hole 11a from the air ejection hole 4a.
[0026]
Here, since the ink droplet 3a is ejected from the nozzle 1a at the same time as the air 7 flows into the recording head maintenance unit 11, unnecessary ink whose viscosity has been increased by contact with the outside air at the tip of the nozzle 1a or the nozzle 1a. It is possible to discharge paper dust and dust from the periphery to the recording head maintenance unit 11 together.
[0027]
If the ink droplet 3a is ejected from the nozzle 1a with the air ejection hole 4a protruding from the nozzle plate 1 as shown in FIG. 1, the ink droplet 3a overflows around the air ejection hole 4a, and the recording head maintenance unit 11 Needless to say, it cannot be discharged smoothly. In particular, in the case of a drop-on-demand ink jet recording head, ink droplets are likely to adhere to the periphery of the nozzle portion when ink is ejected during recording head maintenance, so that the overflow of ink droplets becomes significant.
[0028]
Therefore, when the recording apparatus is turned on or in recording standby, thickened ink, paper dust, dust, or the like adhering to the periphery of the nozzle portion can be sucked into the air suction hole 11a of the recording head maintenance unit 11.
[0029]
Further, since the air speed and the air volume of the air 7 sent out from the blower 6 and ejected from the air ejection hole 4a are large, paper dust, dust, ink, etc. adhering to the periphery of the nozzle portion do not enter the air duct 4, The cleanability of the nozzle plate can be improved. This is particularly effective in the case of a drop-on-demand ink jet recording head that consumes a small amount of ink.
[0030]
Next, a capping operation around the nozzle portion when the power is turned off, which is another function during recording head maintenance, will be described with reference to FIGS.
[0031]
FIG. 3 is a partial cross-sectional view for explaining the operation of the recording head cap mechanism of the ink jet recording head as an example of the present invention.
[0032]
In FIG. 3, a cap 12 fixed to the inner wall of the air duct 4 is held by a solenoid 9 so as to be pressed against the nozzle 1a. In this state, not only paper dust and dust can be prevented from adhering to the nozzle 1a, but also ink drying of the nozzle 1a can be prevented. The material of the cap 12 is preferably a rubber that is elastic and is not affected by ink.
[0033]
4A is a view of the nozzle plate 1 and the air duct 4 in FIG. 3 as viewed from the direction A. The nozzles 1a arranged in a line at a constant pitch on the nozzle plate 1 are arranged on the inner wall of the air duct 4. FIG. The fixed caps 12 are aligned with each other. Further, an air ejection hole 4a facing the nozzle 1a is provided between the caps 12, respectively.
[0034]
FIG. 4B is a diagram in which the position of the air duct 4 with respect to the nozzle plate 1 in FIG. 4A is shifted by a moving means (not shown) in the B direction which is the nozzle arrangement direction. Here, the nozzle 1a and the air ejection hole 4a are aligned with each other, and shows the state at the time of ink jet recording shown in FIG. 1 or at the time of recording standby shown in FIG. In this state, since the nozzle 1a and the cap 12 are separated from each other, the ink ejection or the like is not adversely affected.
[0035]
In this example, the moving means of the air duct with respect to the nozzle plate is provided on the recording head side, but this moving means may be interlocked with the retracting mechanism of the recording head. This retraction mechanism of the recording head performs an operation of moving the recording head away from the recording paper when a recording paper jam or the like occurs, and a recording head movable means is provided on the recording apparatus side. Since the moving direction of the recording head is the same as the moving direction of the air duct with respect to the nozzle plate in this example, for example, a protrusion is provided on a part of the air duct, and the head moving force on the recording apparatus side is provided via the protrusion. May be configured to transmit to the air duct.
[0036]
【The invention's effect】
As described above, according to the present invention, at the time of ink jet recording and recording standby, the air duct is projected from the nozzle forming surface of the nozzle plate to inject air, so that paper dust, dust and the like adhere to the periphery of the nozzle portion. Not only can this be prevented, but the air duct is retracted toward the nozzle plate during head maintenance, so that the cleanability of the nozzle plate surface can be improved.
[0037]
Further, since the air duct is provided with a cap member for capping the nozzle forming surface of the nozzle plate by the movement of the air duct, it is possible to prevent ink from drying around the nozzle portion.
[0038]
Alternatively, humidified air is jetted from the air duct and the moisture retaining material is provided on the inner wall of the air duct, so that ink drying around the nozzle portion can be prevented.
[0039]
In addition, the air speed and air volume ejected from the air duct during ink jet recording and recording standby are reduced, and the air air speed and air volume are increased during the maintenance operation of the recording head. Ink can be prevented from entering the air duct during the maintenance operation.
[0040]
And since the air duct protrudes from the nozzle plate, there is no risk of the recording paper coming into contact with the nozzle plate when the recording paper is jammed, causing paper dust or dust to adhere to the periphery of the nozzle or giving mechanical impact. .
[0041]
Further, since there is the moisturizing material 5 provided on the inner wall of the air duct, the humidified state in the air duct is stabilized, and drying around the nozzles can be prevented even when the temperature of the recording paper is high.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing an ink jet recording head as an example of the present invention.
FIG. 2 is a partial cross-sectional view for explaining a recording head maintenance operation state of an ink jet recording head as an example of the present invention.
FIG. 3 is a partial cross-sectional view for explaining the operation of a recording head cap mechanism of an ink jet recording head as an example of the present invention.
4 is a schematic view of the nozzle plate 1 and the air duct 4 in FIG. 3 as viewed from the direction A. FIG.
[Explanation of symbols]
1 is a nozzle plate, 1a is a nozzle, 1b is a nozzle forming surface, 2 is an ink chamber, 3 is a filling ink, 3a is an ink droplet, 4 is an air duct, 4a is an air ejection hole, 4b is an air flow path, and 5 is a moisture retention 6 is a blower, 7 is air, 8 is a humidifier, 9 is a renoid, 10 is a recording paper, 11 is a recording head maintenance unit, 11 a is an air suction hole, and 12 is a cap.

Claims (8)

A nozzle plate having a plurality of nozzles arranged in a row at a constant pitch, an ink chamber communicating with the nozzle plate and filled with ink, and a driving means for ejecting ink in the ink chamber from the nozzles; , an air duct provided to surround the nozzle of the nozzle plate consists of an air injection means communicating with said air duct, the ink-jet ink is ejected from the air duct through the nozzle while feeding air to said nozzle recording In the head
The air duct is provided a soluble motion means, at the time of ink jet recording and recording standby injected air and the air duct is projected from the nozzle surface of the nozzle plate, the nozzle plate the air duct during maintenance operation of the recording head An ink jet recording head, wherein the air is ejected by retreating to the side . Claim 1 Symbol placement ink jet recording head, characterized in that said movable means of the air duct in conjunction with retraction mechanism of the recording head. 3. An ink jet recording head according to claim 1, wherein said air duct is provided with a cap member for capping the nozzle by moving in the nozzle arrangement direction. Air wind speed at the time of ink jet recording and recording standby injected from the air duct, to reduce the air volume, air wind ejected from the air duct during maintenance operation of the recording head, according to claim 1 to 3, characterized in that to increase the air volume The ink jet recording head according to any one of the above. The ink jet print head according to any one of claims 1 to 4, characterized in that injecting the humidified air from the air duct when the ink jet recording. The ink jet print head according to any one of claims 1 to 5, characterized in that a moisturizing material to the inner wall of the nozzle plate side of the air duct. The ink jet recording head according to any one of claims 1 to 6, wherein the air duct is made of an ink repellent material, or the surface of the air duct is subjected to ink repellent treatment. Recording apparatus comprising the ink jet recording head according to any one of claims 1 to 7.

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