JP2637961B2 - Ink jet recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an ink jet recording apparatus. More specifically, the present invention relates to an ink jet recording apparatus. More specifically, an information signal at the time of recording is applied to a nozzle head to eject ink particles, and information is recorded on a recording medium. to recreate,
The present invention relates to an improvement of a so-called on-demand type ink jet recording apparatus.

[Conventional technology]

The on-demand type ink jet recording apparatus deforms an ink chamber volume of a nozzle head by an information signal, ejects ink particles from nozzle holes, and reproduces information on a recording medium. The recording apparatus does not require a special ink pressurizing mechanism to eject ink particles, and a printer with a simple structure can be obtained.

The above-described on-demand type ink jet recording apparatus has a nozzle section for ejecting ink, and an ink chamber for guiding ink in the ink tank through the ink supply path to the ink nozzle section. Electricity-
By driving the mechanical conversion element, ink particles are ejected onto a recording medium to record an image. In particular, a multi-nozzle head is suitable for high-speed printing and recording of a color image.

By the way, when air bubbles are mixed in the nozzle head of the ink jet recording apparatus, the ejection efficiency of the ink particles is remarkably reduced, and the image of the recording medium becomes uneven.

Conventionally, in the ink jet recording apparatus as described above, detection of air bubbles in the nozzle head is performed by driving the above-described electro-mechanical conversion element and detecting an abnormal nozzle by the air bubble detection means. By operating the bubble exhaust device and discharging bubbles from the abnormal nozzle, the recording image quality is improved.

A conventional technique relating to bubble detection in an ink jet recording apparatus employing a multi-nozzle method is disclosed in, for example,
-262655.

[Problems to be solved by the invention]

Thus, in the conventionally proposed ink jet recording apparatus, the image recording on the recording medium and the bubble detection operation are performed by driving the electro-mechanical conversion element using the same driving pulse voltage. In this type of conventional apparatus, there is a problem in that even when there is no abnormality in the nozzle when detecting bubbles, ink particles are ejected and ink is wasted.

The present invention has been made as a result of reviewing the nozzle head of a conventional ink jet recording apparatus employing a multi-nozzle system, and its purpose is to record an image on a recording medium and to detect an abnormality in the nozzle head (for example, nozzle head). Detection of air bubbles and foreign matter in the nozzle, and detection of nozzle clogging, etc.) even when the electro-mechanical conversion element is driven using the same drive pulse voltage, even when an abnormality is detected in the nozzle head. ,
An object of the present invention is to provide an improved ink jet recording apparatus which has no jetting of ink particles, prevents an increase in the number of parts in the entire apparatus, and further prevents the apparatus from being enlarged in size, and which is excellent in economical efficiency. is there.

[Means for solving the problem]

An object of the present invention is to provide a multi-nozzle ink jet recording apparatus, in which a plurality of electro-mechanical conversion elements are provided for each nozzle, and a part of the electro-mechanical conversion elements provided for each nozzle is subjected to electro-mechanical conversion. An abnormality search signal is applied to the element, and at least one of the electro-mechanical conversion elements provided with the respective nozzles, to which no abnormality search signal is applied, is used as an abnormality detector. And an abnormality detection unit that detects an abnormality by comparing a sensor signal from the abnormality detector with a sensor signal from an electromechanical conversion element serving as an abnormality detector in another nozzle. You.

[Action]

Here, the principle of operation when an abnormality is detected in the nozzle head using the ink jet recording apparatus according to the present invention will be described as follows.

That is, in the present invention, at least one of the at least two electro-mechanical conversion elements provided corresponding to the ink chambers is supplied with a drive pulse signal serving the purpose of detecting an abnormality. Is applied. Then, the drive pulse signal causes a mechanical drive in the ink chamber, the mechanical change propagates to the fluid in the ink chamber, and the hydrodynamic change further changes the electric force applied to the drive pulse signal. -Propagate mechanical changes to electro-mechanical transducers other than mechanical transducers. This series of operations will be referred to as fluid-mechanical vibration. This fluid-mechanical vibration occurs when bubbles or foreign substances are mixed in the fluid in the ink chamber or on the fluid supply side, or when a nozzle that ejects ink particles becomes clogged, and any abnormality occurs. Subtle changes. That is, in the ink jet recording apparatus according to the present invention, the change of the fluid-mechanical vibration is detected by the remaining electric-mechanical transducers of the plurality of electro-mechanical transducers to which the drive pulse signal for abnormality detection is not applied.
This is detected by a mechanical conversion element. In other words, when printing on a recording medium by causing ink particles to fly from the nozzles, a series of drive pulse signals are applied to the plurality of electro-mechanical conversion elements, and the ink particles are ejected by their interaction. However, when performing abnormality detection in the nozzle head, a drive pulse signal serving the purpose of abnormality detection is applied to a part of the plurality of electro-mechanical conversion elements, and the other electro-mechanical conversion elements are used. By detecting a change in the fluid-mechanical drive, an abnormality in the nozzle head is detected.

〔Example〕

Hereinafter, the present invention will be described with reference to the drawings.
FIG. 1A is a partial cross-sectional plan view of a nozzle head showing an embodiment of an ink jet recording apparatus according to the present invention, and FIG. 1B is a sectional view taken along line AA of FIG. 1A.

In FIG. 1, reference numeral 1 denotes a nozzle head, and two nozzles 1a and 1b are arranged in the nozzle head 1. The nozzle head 1 composed of the nozzles 1a and 1b is formed with grooves or by electrostatically bonding the silicon plate 2 and the glass plate 3 to form constrictions 4a and 4b, ink chambers 5a and 5b, and 5a 'and 5a.
b ', and the ink chambers 5a' and 5b '
6a and 6b and the ink chambers 5a and 5b
a, 7b, and the silicon plate 2 has ink chambers 5a, 5b.
b and 5a ', 5b', corresponding to the electro-mechanical conversion elements 8a, 8
b and 9a, 9b are bonded respectively.

In the above configuration, as the first pressure means for the nozzle head 1, drive pulse voltages P _a and P _c shown in FIG. 2 are applied to the electro-mechanical conversion elements 8a and 8b and 9a and 9b, respectively. a second pressure means for one, electro - mechanical conversion element 8a, to 8b, when applying a drive pulse voltage P _b shown in FIG. 2, orifice 6a, each one of the ink particles 10a from 6b, 10b is ejected . That is, as a pressure means for the nozzle head 1, the above-mentioned series of drive pulse voltages P _{a to} P _c are all applied, and only one ink particle 10a, 10b is orifice 6a, 6b respectively.
In other cases, the ink particles 10a and 10b are not ejected from the orifices 6a and 6b.

If this further detail, in Figure 1, an electrical - mechanical conversion element 9a, the 9b, respectively switching switch SW _1, Sn ₂
Are connected, while the electro-mechanical conversion elements 8a, 8b
Is always connected to the drive pulse voltage generation circuit 11,
The switching switches SW ₁ and SW ₂ are connected to the terminals A ₁ and A ₂ , respectively, and the electro-mechanical conversion elements 9 a and 9 b are connected to the drive pulse voltage generation circuit 12, and the electro-mechanical conversion elements 8 a and 8 b and 9 a and 9 b Against
Drive pulse voltages P _a and P _c shown in FIG. 2 are applied, respectively.
Thereafter, electro - mechanical conversion element 8a, to 8b, by applying a driving pulse voltage P _b shown in FIG. 2, orifice
One ink particle 10a, 10b is ejected from each of 6a, 6b, and information is reproduced on a recording medium. In the above description, the case where the ink particles 10a and 10b are ejected from the orifices 6a and 6b at the same time is exemplified. However, it is needless to say that the ink particles 10a and 10b are controlled by controlling the driving pulse signal.
By adjusting the ejection timing of b, it is possible to eject the ink particles 10a and 10b continuously or intermittently.

On the other hand, when performing an abnormality detection operation in the nozzle head 1 (in the following description, for convenience of explanation, the description will be made by taking an example of bubble detection as an example of abnormality detection), the switch SW _{1 is used.} , SW ₂ are switched to the terminals B ₁ and B ₂ respectively, the electro-mechanical conversion elements 9 a and 9 b are connected to the sensor device 13, and one pulse voltage search signal P _d shown in FIG. When voltage is applied to the electro-mechanical conversion elements 8a and 8b from the circuit 11,
When a and 8b are driven, pressure vibrations are generated in the ink chambers 5a and 5a 'and 5b and 5b'. Then, these pressure vibrations are extracted as two electric signals from the electro-mechanical conversion elements 9a and 9b constituting the abnormality detector, and then input to the sensor device 13, and the nozzles 1a and 1b are obtained from the difference signal. Detects the presence or absence of air bubbles in the interior.

Here, the operation example of the bubble detection in the nozzles 1a and 1b will be described in more detail with reference to FIGS. 4 and 5. FIGS. 4 (a) to 4 (d) show the nozzle head 1 shown in FIG. Various electric signal waveform diagrams at the time of bubble detection operation, FIG.
The figure is an explanatory view of the internal structure of the sensor device indicated by reference numeral 13 in FIG.

As described above, the pulse voltage search signal P shown in FIG.
_{When d} is applied to the electro-mechanical conversion elements 8a, 8b of the two nozzles 1a, 1b shown in FIG. 1, if no bubbles exist in both nozzles 1a, 1b, an abnormality detector other electrical constituting the - mechanical conversion element 9a, the 9b, the electric signal P _e shown in FIG. 4 (a) is output. Then, the two electrical signals P _e mentioned above, C of FIG. 5, when input to a differential amplifier 14 for outputting a difference signal in the two inputs of the D terminal, the difference signal of the output, Fig. 4 (c) As shown in FIG. 7, the electric signal _Pg becomes almost zero, the voltage comparator 15 does not operate, and the display device 16 made of, for example, a light emitting diode does not light. Similarly, for example, assuming that no air bubbles exist in the nozzle 1a shown in FIG. 1B and air bubbles exist in the other nozzle 1b, the electro-mechanical conversion element 9a of the nozzle 1a , similar to the above, the electric signal P _e shown in FIG. 4 (a) is outputted, electric nozzles 1b - the transducer 9b, the electric signal P _f as shown in FIG. 4 (b) is output You. When the two electric signals P _e and P _f are input to the differential amplifier 14 in FIG. 5, the difference signal between the outputs is the electric signal shown in FIG.
P _h, and the is input to a voltage comparator 15, its actuates the output signal display device 16, for example, a light-emitting diode is turned on to detect the presence of air bubbles in the nozzle 1b. That is, as shown in FIG. 5, a comparison voltage source 17 is connected to one end on the input side of the voltage comparator 15, and a comparison signal of a voltage such that, for example, a difference signal of a nozzle without bubbles is not output is set. Therefore, if the input signal, that is, the difference signal is equal to or less than the set value, the comparator 15
When the output signal becomes zero and exceeds the set value, the display device
16 works.

Thus, as it is apparent from the foregoing description, the Nozuruhetsudo 1 Inkujietsuto recording apparatus shown in FIG. 1, all the series of pulse voltage P _a to P _c is applied, the first one of the ink particles 10a, 10b is ejected from the orifices 6a and 6b, respectively. In other cases, the ink particles 10a and 10b are not ejected from the orifices 6a and 6b. In FIG. 1 in which the mechanical conversion elements 9a and 9b are used as bubble detectors, ink particles 10a and 1
0b does not erupt.

As described above, according to the present invention, the image recording on the recording medium and the bubble detection in the nozzle head 1 are performed by using the same driving pulse voltage for the electro-mechanical conversion element (the electro-mechanical conversion element in the embodiment of FIG. 1). Even when the mechanical conversion elements 8a, 8b) are driven, there is no ejection of the ink particles 10a, 10b from the orifices 6a, 6b at the time of the abnormality detection operation in the nozzle head 1, thereby eliminating wasteful consumption of ink. Not only is it impossible, but there is no need to take any measures to deal with the unnecessary ejection of ink.

In addition, in the present invention, it is not necessary to provide a special sensor for detecting bubbles, and for example, in the case of FIG. 1, one of the plurality of electro-mechanical conversion elements 8a, 8b and 9a, 9b Since the electro-mechanical conversion elements 9a and 9b described above can be used for detecting bubbles, it is possible to prevent an increase in the number of parts in the entire apparatus and, consequently, an increase in the size of the entire apparatus.

FIG. 6 is a schematic plan view of a nozzle head 1 showing another embodiment of the ink jet recording apparatus according to the present invention.
The nozzle head 1 shown in the figure has eight nozzles 1a to 1h, and the structure and operation system of each nozzle 1a to 1h
This is the same as the case of the nozzle head 1 shown in the figure.

A drive pulse voltage generation circuit 11 is connected to each of the electro-mechanical conversion elements 8a to 8h of the nozzles 1a to 1h, while the electro-mechanical conversion elements of the four nozzles 1a to 1d are connected.
9a to 9d and the electro-mechanical conversion elements 9e to 9h of the other four nozzles 1e to 1h are connected in parallel to the input side of the sensor circuit via resistors 18a and 18b, respectively.

In the sixth figure, when performing, for example, air bubble detection by combining the nozzle 1a and 1e, and enter the pulse voltage search signal P _d shown in FIG. 3 from the driving pulse voltage generating circuit 11 already described, electro - mechanical conversion When the elements 8a and 8e are driven, an electric signal is output from the other electro-mechanical conversion elements 9a and 9e based on the mechanical vibration generated thereby, and this output signal is input to the differential amplifier 14, and thereafter, the same applies. And nozzle 1b
FIG. 7 (a) shows various timing charts of the bubble search signal in the case where the abnormal nozzle can be detected by comparing the values 1f, 1c and 1g, 1d and 1h.

In FIG. 6, the nozzles of group A consisting of 1a to 1d and the nozzles of group B consisting of 1e to 1h each have four combinations (for example, if attention is paid to the nozzle 1a, as described above). In addition to the combination with the nozzle 1e, the nozzles 1a and 1f, 1a and 1g, 1a
And 1h) are possible, and A consisting of 1a to 1d
The flexibility of the combination of the nozzles of the group and the nozzles of the group B consisting of 1e to 1h can be provided.

7 (b) and 7 (c) show examples of bubble detection using a different nozzle combination from FIG. 7 (a).

That is, the example of the bubble detection shown in FIG.
The nozzles 1a to 1d of the group A and the nozzles 1e to 1h of the group B shown in FIG.
In both cases, a bubble search is performed by combining two nozzles each. _First , the group A includes pulse search signals Pd ₁ and Pd _1.
combination of d _2, also Group B searches the presence or absence of by connexion bubbles to a combination of pulse search signal Pd ₅ and Pd _6, then after t becomes the signal processing timing period, A group pulse search signal Pd
The combination of ₃ and Pd ₄ and the B group are the pulse search signals Pd ₇ and Pd ₈
The presence or absence of air bubbles is searched by the combination with.

On the other hand, in the example of bubble detection shown in FIG. 7C, the pulse search signals Pd _{1 to} Pd ₄ and Pd _{5 are} supplied to the nozzles 1a to 1d of the group A and the nozzles 1e to 1h of the group B shown in FIG. To Pd ₈ at the same time, add the respective sensor signals of the electro-mechanical conversion elements 9a to 9d and 9e to 9h, and convert the added sensor signals of the group A and the sensor group B to the differential amplifier 14. , The presence or absence of air bubbles in all the nozzles 1a to 1h can be searched within one search time.

In the illustrated embodiment, the electric power on the ink supply side is
The pulse voltage search signal is input to the mechanical conversion element, and the orifice-side electro-mechanical conversion element is used for the bubble detector. However, on the contrary, the pulse voltage is applied to the orifice-side electro-mechanical conversion element. A search signal may be input, and the electro-mechanical conversion element on the ink supply side may be used for the bubble detector.

Further, in the above-described embodiment, the case of detecting the presence or absence of bubbles has been exemplified as a case of detecting an abnormality in the nozzle head. Also works effectively with the device according to the invention.

〔The invention's effect〕

The present invention is as described above.According to the present invention, in an ink jet recording apparatus employing a multi-nozzle system, the same drive pulse voltage is used for recording an image on a recording medium and detecting an abnormality such as air bubble mixing in a nozzle head. Even when the electro-mechanical conversion element is used to drive the electro-mechanical conversion element, there is no ejection of ink particles at the time of an abnormality detection operation in the nozzle head, and the number of parts as a whole apparatus increases, and as a result, the size of the whole apparatus increases. And an improved ink jet recording apparatus which is more economical can be obtained.

[Brief description of the drawings]

FIG. 1 (a) is a partial cross-sectional plan view of a nozzle head showing one embodiment of an ink jet recording apparatus according to the present invention, FIG. 1 (b) is a cross-sectional view taken along line AA of FIG. FIGS. 3A and 3B are drive pulse voltage waveform diagrams when ink droplets are ejected from the nozzle head shown in FIG. 1, and FIG.
4 (a) to 4 (d) are waveform charts of various electric signals during the bubble detection operation, and FIG. 5 is a first pulse signal search signal waveform diagram during the bubble detection operation of the nozzle head shown in FIG.
Explanatory drawing of the internal structure of the sensor device indicated by reference numeral 13 in FIG.
FIG. 7 is a schematic plan view of a nozzle head showing another embodiment of the ink jet recording apparatus according to the present invention, and FIGS.
(C) shows various timing charts of the bubble search signal generated from the nozzle head shown in FIG. 1. Nozzle head, 1a to 1h ... Nozzle, 5a, 5a 'and 5b, 5b' ... Ink chamber, 6a and 6b ... Orifice, 7
a and 7b ... ink supply paths, 8a to 8h and 9a to 9h ...
Electro-mechanical conversion elements, 11 and 12 pulse voltage generating circuit, 13 sensor device, 14 differential amplifier, 15 voltage comparator, 16 display device.

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasumasa Matsuda 292 Yoshidacho, Totsuka-ku, Yokohama-shi Inside Microelectronics Device Development Laboratory, Hitachi, Ltd. (56) References JP-A-55-118878 (JP, A)

Claims (3)

(57) [Claims] An ink chamber provided for at least one orifice; an ink supply path; and an electro-mechanical conversion element arranged corresponding to the ink chamber. In an ink jet recording apparatus comprising a plurality of nozzles for performing printing by ejecting one ink particle by applying a driving pulse signal to each of the electro-mechanical conversion elements, a plurality of electro-mechanical conversion elements are provided for each of the nozzles. And applying an abnormal search signal to a part of the electro-mechanical conversion elements of the plurality of electro-mechanical conversion elements provided in each of the nozzles, among the electro-mechanical conversion elements provided in the plurality of nozzles, At least one of the electro-mechanical conversion elements to which the abnormality search signal is not applied is used as an abnormality detector, and a sensor signal from the abnormality detector and another In the nozzle, the abnormality detector to become electrically - ink jet recording apparatus characterized by comprising comprises an abnormality detecting means for detecting the abnormality by comparing the sensor signals from the transducer. 2. The method according to claim 1, wherein two or more nozzles are divided into two groups, a group A and a group B, respectively, and one sensor signal of the group A and one sensor signal of the group B are provided. An ink jet recording apparatus having means for detecting an abnormality by taking a difference from the above. 3. The method according to claim 1, wherein the four or more nozzles are divided into two groups, a group A and a group B, respectively.
N ₁ (N ₁ ≧ 2) sensor signals and N _{2 of} group B (N ₂ ≧ 2, N ₁
= N ₂₎ ink jet recording apparatus having a means for detecting an abnormality by taking the difference between the sensor signals.