JP2004167961A - Ink jet type recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the discharging port of a nozzle from being clogged caused by evaporating a solvent portion in an ink without performing a blank discharge. <P>SOLUTION: This ink jet type recording device 20 is equipped with a head 1 which discharges ink drops from the discharging port of the nozzle by an ink jet method, a receiving tray 21 which is arranged in a manner to be adjacent by a distance for not coming into contact with the head 1 under the head 1, and filled with the solvent 31 constituting the ink, and a head moving device 22 which moves the head 1 at the time of recording, and moves the head 1 to the location of the receiving tray 21 when the head 1 is not used. The ink jet type recording device is also equipped with a driving pulse voltage applying circuit 23 which applies a driving pulse voltage to a piezo element 12 of the head 1, and a control circuit 24 or the like which performs a moving control through the head moving device 22 and a control of a meniscus location of the head 1 through the driving pulse voltage applying circuit 23. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink jet recording apparatus that records an image or the like by discharging ink from a nozzle discharge port by an ink jet method.
[0002]
[Prior art]
9 and 10 are views showing an example of a head of a conventional ink jet recording apparatus.
As shown in FIG. 9, the head 1 has a plurality of nozzles 13 arranged therein, and a meniscus of the ink 30 supplied into the nozzles 13 by piezoelectric (piezo) driving for applying a voltage to a piezoelectric element (piezo element). By controlling the position, the ink droplet 30a is ejected in a predetermined ejection direction A.
Here, the nozzle 13 is a penetrating hole in a plate formed by laminating thin plates and fusing the joining surfaces by applying a high temperature, and is a portion from which ink droplets are ejected. The meniscus refers to the ink level in the nozzle 13. 2. Description of the Related Art A piezoelectric element is a device that converts an electric input into a mechanical output through a piezoelectric effect and drives a load, and a piezo element is mainly used. The ink is supplied to an ink tank in the head 1.
[0003]
The head 1 can control a meniscus position as shown in FIG. 10B by applying a voltage to the piezo element with an applied waveform as shown in FIG. 10A as an example.
In this control, in the case of FIG. 10, the potential difference is 100 [V], and the potential difference is large, so that the vibration of the meniscus position is large, and as a result, the ink droplet 30a can be ejected.
[0004]
FIG. 11 is a view showing a state in which the solvent in the ink in the nozzle portion evaporates and the nozzle discharge port is clogged when the head of the conventional ink jet recording apparatus does not discharge for a long time.
In the ink jet recording apparatus, if the ink 30b is clogged due to evaporation of the solvent, even if the ink is not completely clogged, a flying bend or the like occurs and the basic performance is impaired.
[0005]
Conventionally, when the ejection port of the nozzle is clogged due to evaporation of the solvent in the ink at the nozzle portion when ejection is not performed for a long time, for example, empty ejection is performed to forcibly remove the clogged component. I was going.
This idle ejection is not ejected to the printing medium, but is ejected away from the medium in order to remove clogging or the like, and is also called a purge operation.
[0006]
[Problems to be solved by the invention]
However, according to this method, a large amount of ink is used by performing idle discharge, which causes a problem that cost increases, ink supply work and time increase.
In addition, there is a problem that it is necessary to perform processing of waste ink generated by idle discharge.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet type recording apparatus capable of preventing a discharge port of a nozzle from being clogged due to evaporation of a solvent component in ink without performing idle discharge.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 provides a head unit (1) for discharging ink from a nozzle discharge port by an ink-jet method, and a solvent constituting the ink from a nozzle discharge port side of the head unit. By controlling a meniscus position of the ink supplied into the nozzles of the head unit and the solvent supplied from the solvent supply unit into the nozzles. And a drying prevention unit (24, S104) for preventing drying of the ink.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings and the like.
FIG. 1 is a block diagram showing an embodiment of an ink jet recording apparatus according to the present invention.
The ink jet recording apparatus 20 according to the present embodiment is arranged so that a head 1 that discharges ink droplets from nozzle orifices by an ink jet method is disposed below and close to the head 1 at a distance that does not contact the head 1. The receiving tray 21 in which the solvent 31 is immersed, a head moving device 22 for moving the head 1 during recording and moving the head 1 to the receiving tray 21 when not in use, and a piezo element 12 of the head 1 to be described later. A drive pulse voltage application circuit 23 for applying a pulse voltage, a control circuit 24 for controlling movement via the head moving device 22 and controlling the meniscus position of the head 1 via the drive pulse voltage application circuit 23 are provided. ing.
[0010]
Here, the ink 30 is mainly composed of a pigment + solvent and a dye + solvent. Normally, the solvent evaporates under air, and the ratio of the pigment and the dye component increases to increase the viscosity.
In the present embodiment, when the ink 30 for inkjet is used, BCA (butyl carbitol acetate) can be used as the solvent 31.
[0011]
FIG. 2 is a perspective view showing an example of a head constituting the ink jet recording apparatus of the present embodiment.
In FIG. 2, a head 1 is an ink-jet type head, and a plurality of ink ejection units 2 are formed and arranged inside a head member 3.
Each ink ejection unit 2 includes an ink chamber 11, a piezo element 12 for changing the volume of the ink chamber 11, and a nozzle 13 communicating with the ink chamber 11 and ejecting ink to the outside.
[0012]
The ink chamber 11 of the ink discharge section 2 is connected to the ink supply path 4 via the ink supply port 5. In the illustrated example, the ink supply ports 5 are provided alternately at both ends of the ink supply path 4.
The ink chambers 11 are also arranged alternately on both sides of the head 1, and the nozzles 13 are positioned so as to form a straight line.
[0013]
FIG. 3 is a longitudinal sectional view taken along line AA of one ink ejection section 2 of the head shown in FIG. 2, and FIG. 4 is a BB section of one ink ejection section 2 of the head shown in FIG. It is a cross-sectional view in a line.
3 and 4, the piezo element 12 is mounted on the head member 3 such that the deformable surface 12a is in contact with the inside of the ink chamber 11 via the elastic plate 14 and can be deformed by voltage application as described later. ing.
Each piezo element 12 is provided with a central electrode 15a for applying a voltage and a plurality of grounded electrodes 15b, and a variable resistor (not shown) is connected to the central electrode 15a. .
[0014]
When a voltage is applied to the central electrode 15a and an electric field (indicated by a dashed line in FIG. 4) is formed between the central electrode 15a and the ground electrode 15b, the piezo element 12 is distorted and deformed, and the ink chamber 11 is deformed. Is increased, the internal pressure decreases, and ink is drawn into the ink chamber 11 from the ink supply path 4 via the ink supply port 5.
Next, by stopping the voltage application, the piezo element 12 returns to the original state, the pressure in the ink chamber 11 increases, and the ink is extruded and ejected from the nozzle 13.
Therefore, by applying a drive pulse voltage to the center electrode 15a, ink droplets are ejected from the nozzle 13 at intervals synchronized with the drive pulse.
[0015]
FIG. 5 is a flowchart illustrating the operation of the ink jet recording apparatus according to the embodiment, and FIGS. 6 to 8 are schematic diagrams illustrating the operation of the ink jet recording apparatus according to the embodiment.
In S101, a time T0 at which the ejection port of the nozzle 13 is clogged due to the evaporation of the solvent 31 in the ink 30 at the nozzle 13 and the ejection of the ink droplet 30a becomes defective is investigated and set in advance.
[0016]
In S102, the meniscus control is performed and adjusted so that the meniscus position in the nozzle 13 is farthest from the discharge port of the nozzle 13.
[0017]
In S103, the head 1 is moved to the position of the tray 21 to supply the solvent 31 to be drawn in from the discharge port of the nozzle 13.
Here, as shown in FIG. 6, the solvent 31 is drawn from the discharge port of the nozzle 13 by utilizing the vacuum state generated by the meniscus position being drawn from the discharge port of the nozzle 13.
[0018]
In S104, after the ink is sucked, the meniscus position is controlled so that the ink in the nozzle does not seep out from the ejection hole so that the ink in the nozzle becomes uniform.
[0019]
As shown in FIG. 7, the control of the meniscus position is performed in a range where the ink 30 does not ooze out of the ejection hole so that the sucked solvent 31 and the ink 30 in the nozzle 13 are uniform.
At this time, the waveform to be controlled has a potential difference as low as 25 [V], as shown in FIG. 8, so that the meniscus position moves, but does not receive the energy required for ejection, and thus oscillates repeatedly. Will be.
[0020]
In S105, it is determined whether or not a predetermined time has elapsed. If the predetermined time has elapsed, the process proceeds to S106.
In S106, it is determined whether or not the printing operation, that is, the ink discharging operation is performed. If the discharging operation is not performed, S102 to S105 are repeated. If the discharging operation is performed, the process returns.
[0021]
In the case where the ejection is not performed for a long time, it is preferable that the solvent that has evaporated every 24 hours before the ejection port of the nozzle is clogged be sucked from the nozzle ejection port.
Thereafter, in the meniscus control, a waveform as shown in FIG. 8 may be applied for 10 [s] within a range in which the ink does not ooze from the ejection port. The above values are all found from test results.
[0022]
As described above, according to the present embodiment, for example, when the ejection is not performed for a long time, the meniscus position is controlled, and the evaporated solvent is drawn into the nozzle, thereby preventing the ink from drying. It is possible to prevent the ejection opening of the nozzle from being clogged due to the evaporation of the solvent component in the ink in the nozzle portion, thereby preventing the ejection failure of the ink droplet.
[0023]
【The invention's effect】
As described above, according to the present invention, when the ejection is not performed for a long time, the meniscus position is controlled, and the evaporated solvent is drawn into the nozzle, thereby preventing the ink from drying. In addition, it is possible to prevent ejection failure of ink droplets.
Accordingly, it is possible to prevent the ink from drying even without performing the idle discharge, and it is possible to reduce the amount of used ink, and to shorten the work and time for supplying the ink to the inkjet head. Further, waste ink due to idle discharge can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of an ink jet recording apparatus according to the present invention.
FIG. 2 is a perspective view showing an example of a head constituting the ink jet recording apparatus of the embodiment.
FIG. 3 is a longitudinal sectional view of one ink ejection section 2 of the head shown in FIG. 2 taken along line AA.
FIG. 4 is a cross-sectional view of one ink ejection section 2 of the head shown in FIG. 2 taken along line BB.
FIG. 5 is a flowchart illustrating an operation of the ink jet recording apparatus according to the embodiment.
FIG. 6 is a schematic diagram illustrating the operation (drawing of a solvent) of the ink jet recording apparatus of the present embodiment.
FIG. 7 is a schematic diagram illustrating an operation (control of a meniscus position) of the ink jet recording apparatus according to the embodiment.
FIG. 8 is a schematic diagram for explaining the operation (applied waveform) of the ink jet recording apparatus of the present embodiment.
FIG. 9 is a diagram illustrating an example of a head of a conventional ink jet recording apparatus.
FIG. 10 is a diagram illustrating an example of a head of a conventional ink jet recording apparatus.
FIG. 11 is a diagram illustrating a state in which the solvent in the ink at the nozzle portion evaporates and the nozzle orifice is clogged when the head of the conventional ink jet recording apparatus does not eject for a long time.
[Explanation of symbols]
Reference Signs List 20 inkjet recording device 21 tray 22 head moving device 23 drive pulse voltage application circuit 24 control circuit 1 head 30 ink 31 solvent

Claims (1)

A head section for discharging ink from nozzle discharge ports by an inkjet method,
From the nozzle discharge port side of the head unit, a solvent supply unit that supplies a solvent constituting the ink,
A drying prevention unit for controlling drying of the ink by controlling a meniscus position of the ink supplied to the nozzles of the head unit and drawing the solvent supplied from the solvent supply unit into the nozzles; When,
An ink jet recording apparatus comprising:

Images