Liquid drop ejector and method for detecting/judging abnormality of head

Abstract

A droplet ejection apparatus of the invention includes: a plurality of droplet ejection heads (100); ejection failure detecting means (10) for detecting an ejection failure of droplets through nozzles; and recovery means (24) for performing recovery processing to eliminate a cause of the ejection failure of the droplets, wherein in a case where detection by the ejection failure detecting means (10) is performed for all of the nozzles and the presence of a failing nozzle in which an ejection failure is occurring is detected, recovery processing depending on the cause of the ejection failure is performed by the recovery means (24) at least for the failing nozzle, after which detection by the ejection failure detecting means (10) is performed again by forcing the failing nozzle alone to perform a droplet ejection operation.

Description

field of invention [0001] The present invention relates to a liquid drop ejecting device and a method for recovering abnormal ejection. Background technique [0002] An inkjet printer, which is one of the droplet ejection devices, ejects ink droplets (droplets) from a plurality of nozzles to form an image on predetermined paper. The print head (inkjet head) of an inkjet printer is equipped with multiple nozzles, but due to reasons such as increased ink viscosity, air bubbles, dust and paper dust adhesion, sometimes several nozzles are blocked and ink droplets cannot be ejected. When the nozzles are clogged, missing dots are generated in the printed image, which causes image quality to deteriorate. [0003] In the past, as a method for detecting such an abnormality in the ejection of ink droplets (hereinafter also referred to as "missing dots"), in Japanese Patent Laid-Open No. 8-309963, a method is disclosed. A state in which ink droplets are not ejected from the nozzles o...

AI Technical Summary

Problems solved by technology

Such detectors are generally expensive, and as a result there is a problem of increasing the manufacturing cost of inkjet printers

In addition, the reliability of the detector may also become a problem due to the contamination of the light source output part and the detection part of the optical sensor due to mis-ejection of ink from the nozzle and paper powder such as printing paper.

[0005] In the above-mentioned optical leak detection method, the leak of the nozzle can be detected, i.e., the ejection of the ink droplet is abnormal (not ejected), but the cause of the leak (abnormal ejection) cannot be judged (determined) based on the detection result, Cannot choose to perform the appropriate recovery process corresponding to the cause of the leak point

Therefore, in the missing dot detection method of the prior art, the sequence recovery process is performed regardless of the cause of the missing dots. For example, in the wiping process, regardless of whether it is a recoverable state, by sucking ink from the inkjet head with a pump, etc., the discharge rate is increased. Ink (Useless ink), due to inability to perform proper recovery processing, will reduce or deteriorate the throughput of the inkjet printer (droplet ejection device) by performing multiple recovery processes

[0006] However, generally, a droplet ejection device (inkjet printhead) has a plurality of nozzles and corresponding actuators, but in such a droplet ejection device with a plurality of nozzles, it is difficult to reduce or deteriorate the throughput of the device. In the case of liquid droplet (ink) ejection abnormality (non-ejection) is detected, that is, dot omission during printing (recording) operation is detected

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