JPS5830832B2 - inkjet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording device used in facsimile receivers and the like, and more particularly to an inkjet recording device provided with means for preventing clogging of nozzles.

Generally, in the recording head of an inkjet recording device, if the minute nozzles that eject ink particles (hereinafter referred to as ejection nozzles) are left in contact with air for a long time, the ink near the ejection nozzles dries and becomes highly viscous. Become,
As a result, a problem occurred in that the nozzle became clogged.

Hereinafter, the problems of this conventional technique will be explained in detail based on the drawings.

FIG. 1 is a schematic diagram showing a conventional on-demand type inkjet recording apparatus.

In FIG. 1, numeral 1 denotes a recording head that performs recording, and numeral 2 denotes an ink supply tank storing ink a.

Reference numeral 3 indicates an ejection nozzle that is opened in the recording head 1 and ejects ink particles, 4 is a piezoelectric element, and input terminals f, .
An image signal is input from f2, and in accordance with this image signal, the ink a in the ink chamber 8 in the recording head 1 is pressed to eject ink particles from the ejection nozzle.

5 is a tube for supplying ink a stored in the ink supply cylinder 2 into the recording head 1, 6 is a recording paper, and 7 is an ink particle.

Next, the operation of the conventional inkjet recording apparatus having the above configuration will be explained.

Input terminal f1 of piezoelectric element 4. When an image signal is applied to f2, the piezoelectric element 4 vibrates, and the ink a in the recording head 1 is pressed in accordance with this image signal.

Therefore, ink particles 7 are ejected from the nozzle 3, adhere to the recording paper 6 provided at a predetermined position, and recording is performed.

Note that the ink a, which is the source of the ink particles 7, is supplied from the ink supply tank 2 through the pipe 5.

However, the above inkjet recording apparatus has various problems.

In particular, the ejection nozzle is a minute opening provided in the recording head, and as mentioned above, if the ejection nozzle is left in contact with air for a long time, the ink near the nozzle dries and becomes more viscous, causing this ejection. The nozzle becomes clogged.

Conventionally, as a countermeasure against clogging of discharge nozzles, many clogging prevention or clogging devices have been devised.

These devices can be broadly classified into those using the following six methods.

(a) A method of covering the ejection nozzle when not recording.

(Middle) A method of sealing the ejection nozzle with saturated vapor of ink solvent when not recording.

(c) A method of intermittently ejecting ink particles in a time cycle that does not cause clogging of the ejection nozzle during non-recording.

2) A method of extracting ink from the print head when not printing.

(e) A method of applying slight vibrations to the recording head when not recording and using this vibration energy to prevent clogging of the ejection nozzles.

(F) Even if the ejection nozzle becomes clogged during non-recording, a method of eliminating the clogging by adding ink solvent to the ejection nozzle before recording.

However, the above-mentioned six methods have practical drawbacks as shown below.

In method (a), when dust or the like adheres to the lid, this dust or the like may enter the discharge nozzle, making it impossible to perform normal recording.

Methods (b) and (f) require the installation of a new ink solvent tank, making the configuration complicated.

In method (c), if the non-printing time is long, a large amount of ink is intermittently ejected, resulting in a lot of waste.

In method (2), after ink is drained from the print head during non-printing, when ink is injected into the print head for printing again, air tends to get trapped, which may prevent normal printing.

Method (e) applies vibration from outside the recording head,
Screws and the like that support the recording head tend to loosen, causing the recording head to become misaligned and making it impossible to perform normal recording.

As described above, each of the above-mentioned conventional methods for preventing or eliminating clogging of a discharge nozzle has its own drawbacks.

SUMMARY OF THE INVENTION In view of the drawbacks of the conventional methods for preventing or eliminating clogging of ejection nozzles of a recording head, an object of the present invention is to provide an inkjet recording apparatus that provides a method for reliably eliminating clogging of ejection nozzles of a recording head. It's about doing.

Hereinafter, an inkjet recording apparatus according to the present invention will be explained in detail based on the drawings.

FIG. 2 is a schematic configuration diagram showing an embodiment in which the present invention is applied to an ink jet recording apparatus having an air flow mechanism.

In FIG. 2, numeral 9 is an air pump that applies pressure to air and supplies air C at a constant air pressure to the ink supply tank 2 together with the recording head 1; This is an air pressure regulator that adjusts the air pressure and supplies it to the recording head 1.

Reference numeral 11 denotes an ejection nozzle, in which the ink a supplied from the ink supply tank 2 through the pipe 5 to the ink chamber 8 of the recording head 1 is applied to the ink particles ejected from the ejection nozzle 3 by the vibration of the piezoelectric element 4, and the air pressure regulator Ink particles are ejected and adhered onto the recording paper outside the recording head 1 by air C supplied from the recording head 1 to the recording head 1 through the air supply pipe 12.

13 is a three-way pipe that guides the air C supplied from the air pump 9 to the air pressure regulator 10 and also to the ink supply tank 2, pressurizes the ink a in the ink supply tank 2 and releases the ink a. It is guided to the ink chamber 8 of the recording head 1.

14 is an on-off valve such as a solenoid valve which forms the main part of the present invention;
The air flow supplied from the air pump 9 through the three-way pipe 13 is interrupted by a signal input from the input terminal g12g2,
It is allowed to pass.

Note that the same members and locations as in FIG. 1 are given the same numbers.

Next, the operation of this embodiment having the above configuration will be explained.

First, at the time of recording, the input terminal g12g of the on-off valve 14
A signal for opening the on-off valve 14 is input to 2, and the air C from the air pump 9 presses the ink a in the ink supply tank 2 via the three-way pipe 13, and the air pressure regulator I am led by 10.

The ink a in the ink supply tank 2 pressurized by the air pump 9 is supplied to the ink chamber 8 in the recording head 1 via the pipe 5.

Next, the input terminal f1 of the piezoelectric element 4. When an image signal is input to f2, a pressure corresponding to this image signal is applied to the ink a in the ink chamber 8, and ink particles are ejected from the ejection nozzle 3.

Here, air at a predetermined pressure is guided to the recording head 1 by the air pressure regulator 10, and this air causes the injection nozzle 1 to
Ink particles are ejected from 1.

The on-demand inkjet recording device having this air flow mechanism accelerates incoming particles ejected from the ejection nozzle 3 by the air flow supplied from the air pump 9 in order to improve the flying distance and flying speed of the ink particles. This differs from the on-demand type ink jet recording apparatus in that the inkjet recording apparatus can be reliably attached to the recording paper.

During non-recording, the air pump 9 stops its operation;
Air C having a predetermined pressure is no longer supplied to the ink supply tank 2 and the air pressure regulator 2.

Note that this crest on-off valve 14 is open.

Therefore, the ink a supplied to the ink chamber 8 in the recording head 1 is not pressed, and therefore no ink particles are ejected.

Next, the operation immediately before recording will be explained.

Open/close valve 1 for a predetermined time to input terminal g12g2 of open/close valve 14
Input the signal that causes 4 to close.

When the air pump 9 operates and the on-off valve 14 closes, all of the air C sent from the air pump 9 passes through the three-way pipe 13,
The liquid level of the ink a in the ink supply tank 2 is pressed, and the pressure of the ink a increases.

Therefore, the pressure of the ink a in the ink chamber 8 in the recording head 1 also increases, the ink a is pushed out from the ejection nozzle 3, and the clogging of the ejection nozzle 3 that is in the clogging state is cleared.

Note that the timing at which the on-off valve 14 closes is determined by the air pump 9.
It is counted by a predetermined value counter etc. from the time when it starts operating,
At the same time as the counting is completed, a signal indicating that the on-off valve 14 is closed is inputted to the input terminal g12g2 of the on-off valve 14, and a predetermined value sufficient to eliminate the clogging is counted using a counter or the like, and the signal is input to the input terminal g.
A signal indicating that the on-off valve 14 is open is input to 12g2.

As is clear from the above description, the inkjet recording device according to the present invention pushes out the ink remaining at the tip of the inkjet nozzle to the outside of the inkjet nozzle immediately before recording, so even if the nozzle becomes clogged, It can be easily resolved.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a conventional on-demand type inkjet recording device, a schematic configuration diagram of the recording device, and FIG. 2 is a schematic configuration diagram of an on-demand type inkjet recording device having an air flow mechanism showing another embodiment of the present invention. It is a diagram. 1... Recording head, 2... Ink supply tank, 3... Ejection nozzle, 4...
Piezoelectric element, 8... Ink chamber, 9... Air pump, 10... Air pressure regulator, 11...
...Injection nozzle, 14...Opening/closing valve.

Claims (1)

[Claims] 1. An inkjet recording bed that includes a first nozzle for ejecting ink particles and a second nozzle that covers and faces the first nozzle, and that generates and ejects ink particles;
a storage chamber for ink to be supplied to the recording pen H; and for pressurizing the ink in the storage chamber to supply the ink to the recording head and to cause ink particles discharged from the first nozzle to fly from a second nozzle. an air pump for creating an air flow, an air pressure adjustment means provided in a part of an air supply pipe connecting the air pump and the recording head, and an air pressure adjustment means provided between the air pressure adjustment means and the air pump. An inkjet recording device comprising an on-off valve for a supply pipe, the on-off valve being closed only immediately before recording starts.