JPS63173648A - Detection of erroneous jetting in ink jet printer - Google Patents

Abstract

PURPOSE:To securely detect erroneous jetting of an ink dot, by jetting ink droplets to an erroneous jet detecting electrode pair disposed opposite to a recording head, and detecting normal jetting of the ink droplets based on an electric current flowing between the pair of the electrodes. CONSTITUTION:A recording head 25 comprising n-jet nozzles 26 for each page of a recording paper is moved to a position opposite to a erroneous jet detector 29. When ink droplets 8 are sequentially jetted, ink dots 9, 10...14 jetted respectively from first, second... jet nozzles 26 sequentially reach detection gaps 2, 3...7 between a common electrode 1 and discrete electrodes 16. When the ink dots are normally jetted, electric currents flow in corresponding wirings 15, and when the electric currents do not flow, erroneous jetting is detected. When the erroneous jetting is detected, the head 25 is moved to a purging position 31, and the ink is forced to flow out of the head by a purging mechanism 30, thereby clogging with the ink or the like is solved. Thus, secure erroneous jetting detection can be performed even for a recording head with any dot diameter and any number of jet nozzles.

Description

[Detailed Description of the Invention] Industrial Application Field 1 The present invention relates to a method for detecting ejection errors in inkjet printers, and particularly in on-demand type inkjet printers, whether or not ink particles ejected from the ejection nozzles of a recording head are ejected normally. The present invention relates to an injection error detection method for detecting whether or not an injection error occurs.

! BACKGROUND ART An on-demand inkjet printer uses a method in which ink particles are ejected from a nozzle by changing the volume of a pressure chamber each time an electric pulse is applied to a piezoelectric transducer of a recording head in response to an electric signal for recording. It is. In this type of on-demand inkjet printer,
Compared to so-called continuous inkjet printers, which eject ink particles continuously from a nozzle,
Ink droplet ejection errors are likely to occur. This is because the ejection nozzle of the print head is close to the recording paper, so dust such as paper powder may adhere to the ejection nozzle surface, air bubbles may enter the inside of the print head, or the ink inside the ejection nozzle may dry. This is an abnormal accident such as a mistake in the injection direction or the inability to injection, which occurs due to reasons such as solidification due to changes over time. Missing ink dots on the recording paper due to these ejection errors degrade print quality, so it is necessary to promptly detect this and take recovery measures.

] Problem to be Solved by the Invention 1 However, the method of detecting the above-mentioned injection error is currently performed visually, and everything from detection to recovery measures is performed manually. As a result, there are problems in that monitoring work is cumbersome and the discovery of injection errors is not accurate or quick.Furthermore, there are also problems in the troublesome accident recovery operation and the time required for corrective action.To solve these problems, Various injection error detection devices have been considered so far. SUMMARY OF THE INVENTION An object of the present invention is to provide an ejection error detection device for an inkjet printer that solves such problems and easily detects ejection errors.

]Means for Solving Problems 1 The method of detecting an ejection error according to the present invention is to measure the resistance of ejected ink.

In this method, ink particles containing an electrolyte are ejected to a pair of ejection error detection electrodes placed opposite the ejection nozzle surface of the recording head, and the ink particles are detected depending on whether or not a current flows between the electrode pair. This detects whether or not the fuel is being injected normally, thereby making it possible to reliably detect misfires and eliminating the need for human monitoring.

1 Example 1 FIG. 4 shows the detection principle of the present invention. The dots 9 of ink containing an electrolyte as a component are injected into the detection gap 18 between the common electrode 1 and the individual electrodes 16, and due to the ionization of the electrolyte, a rectangular wave (5 μs) of 1 to 100 μs is generated between the common electrode 1 and the individual electrodes 16. 24 V) is applied, a current flows between the pair of electrodes, and a voltage VOV is generated across the detection resistor 17 in the detection circuit. A circuit (not shown) determines that the injection is erroneous when the generated voltage is o■, and that the injection is normal when it is vov. The electrolyte is
There are dyes, preservatives, chelating agents, pH 1 regulators, etc. The common electrode 1 and the individual electrodes 16 can be formed of a metal thin film of nickel, chromium, gold, or the like formed by photolithography or printing on an insulator such as glass (not shown).

FIG. 1 is a configuration diagram of an electrode pattern showing an embodiment of the present invention. The recording head is mounted on a carriage controlled by a space feed position detector (not shown) and is scanned from left to right across the electrode pattern in the figure. As the carriage scans, the 1# injection nozzle among the n injection nozzles of the recording head (not shown) reaches a point 8 about 2 to 20 dots away from the 1# dot detection gap 2, and then the 1# injection nozzle Start ink jetting from .

When the carriage moves to the right and the dot reaches the 1# dot detection gap 2, a current flows between the common electrode 1 and the individual electrode 16, and a potential is generated in the detection circuit (not shown) connected to the wiring group 15, thereby establishing continuity. It turns out that The absolute position of the position detector at this time is memorized, and a certain distance d is
When the 2# injection nozzle reaches the 2# dot detection gap 3 which is m+a away, ink is ejected from the 2# injection nozzle and an ejection error is detected. The carriage further moves to the right and dims.
The distant 3# dot detection gap 4 detects the injection error of the 3# injection nozzle. Thereafter, the remaining injection nozzles are detected in the same manner. If a jetting error is detected during the process, the recording head will automatically return to its original state at that point.

When the amount of ejected ink is small and it is not possible to fill between the electrode pairs with one dot, or when the electrode pattern is too fine and manufacturing is difficult and the detection gap is widened, the common electrode 1 is used as shown in Figure 2. , a plurality of dots (for example, three dots) are injected so that dots are continuous between the individual electrodes 16. 1#
When detecting the dot detection position, the position 19 of a plurality of injection dots (3) before the injection dot for which continuity was obtained is memorized and used as the reference position for the detection of injection errors after the 2# dot. ) to detect injection errors.

This method allows use with inkjet heads of any dot diameter.

By carrying out these embodiments, the objects of the present invention can be achieved.

Next, the operation of the inkjet printer equipped with the ejection error detection device configured as described above will be explained.

FIG. 3 is a configuration diagram showing one embodiment of an inkjet printer. The inkjet printer selectively ejects ink particles from n internal ejection nozzles 26 while scanning a preset recording section of recording paper with a recording head 25 mounted on a carriage 24. Printing is performed on the recording paper 28 on the platen 27 facing the head 25, and is printed every predetermined number of times and for a predetermined period of time (for example, 60
2 recording heads per second) or per page of recording paper.
5 is moved in front of the ejection error detection device 29, and while moving the carriage 24, ink is sequentially ejected from all the ejection nozzles 26, and the ink ejection error is detected by the detection circuit. If an ejection error is detected, the print head is moved to the purge position 31 outside the print section, and the ink inside the print head 25 is forcibly flowed out by the purge mechanism 30. Remove air bubbles, solidified ink, and dust inside and outside the jet nozzle.

Further, if no ejection error is detected, the printing operation is executed again.

[Advantageous Effects of the Invention 1] As described above, according to the present invention, it is possible to reliably detect ink dot ejection errors for recording heads with any dot diameter and any number of ejection nozzles. Furthermore, since the mutual positioning of the recording head and the ejection error detection device can be easily achieved by ejecting a plurality of dots from an arbitrary ejection nozzle, the design of the inkjet printer is also facilitated. According to the device of the present invention, it is easy to operate, and injection errors can be detected accurately and quickly. Furthermore, since recovery measures are automatically performed even after detection, it is easy for printer users to use.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention. FIG. 2 is a configuration diagram showing an embodiment of the present invention. FIG. 3 is a configuration diagram of an inkjet printer. FIG. 4 is a configuration diagram showing the detection principle of the present invention. 5...4# dot detection gap, 6...(n-1)
#Dot detection gap, 7...n#Dot detection gap, 10 ・2 #dot, 11...3#dot,
12...4# dot 13...(n-1) dot,
14...n# dot, 20...dot that complements between electrodes, 21...open collector buffer, 22...
...Pull-up resistor, 23...Guide shaft. Applicant: Seiko Epson Co., Ltd. Representative Patent Attorney Tsutomu Mogami and 1 other person Figure I11 Figure 2

Claims (1)

[Claims] In an inkjet printer jetting error detection method for detecting whether or not ink particles are jetted normally from a jetting nozzle of a recording head of an inkjet printer, in order to detect jetting mistakes, a plurality of jetting nozzles are An ink containing an electrolyte as a component is ejected from any one of the ejection nozzles toward a pair of ejection error detection electrodes formed on opposing substrates, and is scanned. After detecting the relative position of the injection nozzle and the electrode pair group based on the presence or absence of electrical continuity between the electrode pairs, sequentially starting from the injection nozzles other than the arbitrary one injection nozzle, using the arbitrary one injection nozzle as a reference. An ejection error detection method for an inkjet printer, characterized in that ejection errors of all ejection nozzles are detected by ejecting ink particles at predetermined positions of the ejection error detection electrode pair group and sequentially detecting electrical continuity.