JPS59227456A - Ink jet printer - Google Patents

Abstract

PURPOSE:To issue the alarm for an ink residual amount and to make it possible to continuously perform printing even if an ink residual amount is reduced, by supplying ink from the other ink container by the usually performed manipulation of a restoration system when the ink residual amount is reduced and a printing state becomes inferior. CONSTITUTION:An ink bag 7' is provided to the half-way of the arranged pipe to a nozzle 1 along with a valve or membrane 8 without being provided in an ink bag 5. This valve or membrane 8 is formed so as to be capable of sufficiently withstanding printing negative pressure during usual printing and preliminarily adjusted so as to be opened when a printing state become inferior as the result of the reduction of an ink residual amount and sucking work is performed by using a restoration system. When printing operation is succeeded after the restoration system is manipulated, the alarm of the ink residual amount is performed by the light-colored ink or the different color ink in the ink bag 7'.

Description

TECHNICAL FIELD The present invention relates to an inkjet printer, and more particularly to an inkjet printer equipped with a mechanism for generating suction negative pressure to recover from ink ejection failure.

BACKGROUND ART Traditionally, inkjet printers have used liquid ink to collide with paper in the form of droplets in accordance with the information to be recorded, thereby recording information such as letters and pictures as dots.

Therefore, the ink is stored in a liquid container, and when the amount of ink remaining in the container becomes low due to operation of the printer, an alarm device is provided to notify the user of this fact.

This type of remaining level alarm device includes 1) a flow of 1 in the ink container;
・Type that floats and detects the position of the float, 2
2) A type in which electrodes are provided in the ink container and the conduction state between the electrodes is detected, and 3) A type in which detection is performed using an optical sensor in the supply pipe section between the ink container and the ink ejection device. However, with the float method (1), the detector responds too sensitively to vibrations and rocking, causing a false alarm to be issued even though there is a considerable amount of ink remaining. The method using electrodes (2) has the problem of passing current between the electrodes, which affects the physical properties of the ink if it lasts for a long time, causing problems with ink ejection from the inkjet nozzle.
) In the case of the optical sensor, there is a problem that detection may become inaccurate due to ink sticking to the inner wall of the supply pipe, and it is not possible to accurately detect the remaining amount of ink and issue an alarm.

Also, for small, low-priced inkjet printers,
The so-called ink-on-demand method, which uses a suction method to fill the nozzle tip with ink, is used to restore normal ink ejection conditions, but when the ink is about to run out, the ejection deteriorates and the remaining It is presumed that the amount has decreased, but it is difficult to distinguish from the case where the nozzle is clogged and the ink ejection has deteriorated, and it is only when the ejection does not recover even if the suction method is used to return to normal state. You will find out that the remaining amount of ink has run out or is low.

The conceptual diagram of the ink-on-demand system in a conventional inkjet printer shown in FIG. 1 will be explained below. 1 is an inkjet nozzle; 2 is a suction mechanism, in which a suction pump 3 and a drain ink reservoir 4 are provided. An ink bag 5 containing ink is connected to the nozzle 1 with a tube,
Ink can also be ejected from the nozzle 1 by an ink ejection means (not shown). Reference numeral 6 denotes a cylindrical platen. Paper (not shown) is attached to the surface of this cylinder, and printing is normally performed with the suction mechanism 2 removed.

Although such inkjet printers have the advantage that the energy required to eject ink is very small, once air bubbles form in the nozzle, or if the printer is operated after a long period of rest or if the lamp suddenly changes in temperature, In such cases, when ink cannot be ejected normally from the tip of the nozzle and it becomes stagnant, the suction pump 3 is activated to remove the suction because the energy to break through the ink and eject the ink is not enough. A mechanism 2 is brought into contact with the nozzle 1 to suck out air bubbles accumulated in the nozzle 1 and ink whose viscosity has changed, and refill the nozzle with new ink.

However, as described above, although it is possible to estimate the amount of ink remaining, it is not always possible to accurately detect it, and stable inkjet flashing has not been achieved.

Purpose The present invention was made in order to eliminate the above-mentioned drawbacks of the conventional art, and provides an inkjet printer that is inexpensive and can notify when the amount of ink remaining in an ink container is low. It is intended to.

EXAMPLES The present invention will be described in detail below based on examples shown in the drawings.

2 and 3 illustrate an embodiment of the ink container used in the inkjet printer of the present invention. In FIG. In addition to the printing ink, a second ink bag 7 is stored, and the bag 7 contains ink of a lower density than the normal printing ink or a color different from the normal printing ink. is filled with ink.

It has been experimentally known that when the ink is consumed through the ink nozzle housed in the ink bag 5 during normal printing operations, the degree of negative pressure that attempts to suck the ink into the nozzle is approximately -1nv+t6 or less. There is.

When the remaining amount of ink runs out and the state of ink ejection from the nozzle begins to deteriorate, the suction mechanism 2 is turned off using the recovery system according to the normal operating procedure, that is, as in the conventional example shown in FIG. When it comes into contact with the tip of the nozzle, the suction pump 3 is activated to suck ink. At this time, the suction negative pressure is -8~
-10 mA, a pressure difference several times larger than the negative pressure during normal printing occurs, and during normal printing, the inner ink bag 7, which does not break, absorbs the negative pressure. It ruptures due to negative pressure and the ink inside flows out into the normal printing ink, and the ink that flows out to the nozzle starts to come out with ink of a lower concentration or a different color that was filled in the ink bag 7, worsening the ejection condition. When printing is performed after the printing has been recovered, the user visually recognizes that the density of the printed ink is low or the color has changed.

In this case, even if the color of the printed ink becomes lighter or a different color, the ink does not immediately run out, so there is no need to stop the printer immediately.

In addition, if a small amount of ink for normal printing remains in the ink bag 5, the printing condition may deteriorate due to air bubbles, etc., and the inner second ink bag 7 may be torn when a suction operation is performed. Since the outer normal printing ink storage bag 5 deforms and absorbs the negative pressure before the negative pressure is applied, the normal printing ink is supplied to the nozzle without tearing the second ink bag 7.

What is shown in FIG. 3 is for explaining another embodiment.
The ink bag 7' is provided not in the ink bag 5 but in the middle of the piping to the nozzle 1 together with a valve or membrane 8.

This valve or thin film 8 was designed to be able to sufficiently resist the printing negative pressure during normal printing, but when there was little ink remaining, the printing condition worsened and suction work was performed using a recovery brush. When the valve or membrane 8 opens,
Adjust in advance. When the printing operation is continued after this recovery system operation, the second ink bag 7 is
A warning of ink residue is provided by thin ink or colored ink inside '.

Effects As is clear from the above explanation, according to the present invention, no complicated mechanism is required, and when the remaining amount of ink becomes low and the printing condition worsens, the normal recovery system operation Since the ink is supplied from the ink teapot, the excellent effect of not only providing a warning of the remaining amount of ink but also allowing continuous printing even when the amount of ink remaining is low can be obtained.

[Brief explanation of the drawing]

Claims (1)

[Scope of Claims] 1) In an inkjet printer that uses negative pressure by suction to recover from a discharge failure of a nozzle that discharges ink supplied from an ink container, first and second ink containers are provided, and the first ink An inkjet printer characterized in that the ink is supplied from the second ink container by the negative pressure when the amount of ink remaining in the container becomes less than a predetermined value. 2) The characteristics of the ink in the first and second ink containers are changed, thereby informing that there is less ink remaining in the first ink container. The inkjet printer according to item 1. 3) The inkjet printer according to claim 1 or 2, wherein the second ink container is included within the first ink container.