JPS6287357A - Ink drip detector - Google Patents
Ink drip detectorInfo
- Publication number
- JPS6287357A JPS6287357A JP22831585A JP22831585A JPS6287357A JP S6287357 A JPS6287357 A JP S6287357A JP 22831585 A JP22831585 A JP 22831585A JP 22831585 A JP22831585 A JP 22831585A JP S6287357 A JPS6287357 A JP S6287357A
- Authority
- JP
- Japan
- Prior art keywords
- ink
- electrode
- nozzle
- electrodes
- head
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/07—Ink jet characterised by jet control
- B41J2/125—Sensors, e.g. deflection sensors
Landscapes
- Ink Jet (AREA)
- Particle Formation And Scattering Control In Inkjet Printers (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明はインクジェット印刷装置のインク滴の飛行状態
を検出する検出装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a detection device for detecting the flight state of ink droplets of an inkjet printing device.
インクジェット印刷装置、特にインクオンデマンド型印
刷装置は音は静かであるが、インク滴の飛行が不安定で
あり、種々の外乱によりインクの飛行が不能となる欠点
があった。そこで従来からインク滴の状態を検出し、不
良の場合印刷装置を停止したり、何等かの復帰動作を行
なうことが提案されている。例えば圧電素子の駆動波形
を検出して加圧室内の気泡の有無からインク滴の飛行不
良を検出したり、飛行インク滴に荷電し、インク滴によ
る誘導電流を検出してインク滴速度を検出する方法が提
案されている。Inkjet printing devices, particularly ink-on-demand printing devices, are quiet, but have the disadvantage that the flight of ink droplets is unstable, and the flight of ink becomes impossible due to various disturbances. Therefore, it has been proposed to detect the condition of ink droplets and, if a defect occurs, to stop the printing apparatus or perform some kind of recovery operation. For example, by detecting the driving waveform of a piezoelectric element and detecting the presence or absence of air bubbles in the pressurized chamber, it is possible to detect ink droplet flight failure, or by charging the flying ink droplets and detecting the induced current caused by the ink droplets to detect the ink droplet speed. A method is proposed.
しかし、これらの従来技術では、検出感度が悪かったり
、高電圧を必要としたり、回路が抄雑で高価になる等の
欠点があった。However, these conventional techniques have drawbacks such as poor detection sensitivity, high voltage requirements, and complicated and expensive circuits.
従って本発明の目的は上記欠点をなくした、簡単な回路
構成で確実なインク滴検出装置を得ることにある。SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a reliable ink droplet detection device with a simple circuit configuration, which eliminates the above-mentioned drawbacks.
本発明のインク滴検出装置は、複数の電極を有し、すく
なくともそのひとつはインクを射出するノズルから所定
距離部れて対向配置きれた第１の電極であり、前記ノズ
ルから射出された導電性を有するインクが前記第１の電
極に到達した時の前記第１の電極と、他の電極間の抵抗
値の変化を検出することを特徴とする。The ink droplet detection device of the present invention has a plurality of electrodes, at least one of which is a first electrode disposed facing a predetermined distance from a nozzle that ejects ink, and the ink droplet detecting device has a plurality of electrodes. The present invention is characterized in that a change in resistance value between the first electrode and other electrodes is detected when ink having the above-mentioned ink reaches the first electrode.
本発明によれば、ノズルから射出された導電性インクが
第１の電極と、他の電極間を導通することでインクの第
１の電極への到達が検出でき、これによってインク滴の
飛行状態が検出できる。According to the present invention, the arrival of the ink at the first electrode can be detected by conducting the conductive ink ejected from the nozzle between the first electrode and the other electrodes, thereby determining the flight state of the ink droplets. can be detected.
第１図は本発明の一実施例を示す平断面図で、１はイン
クジェットのヘッド、２は導電性を有する水性のインク
、６はインク２を射出するノズル、４はノズル３に対向
し距離ｌ離れて配置された第１の電極、５は第１の電極
４と距離ｇ離れて配置された第２の電極である。距離１
は０．２７Ｈｆｉないし１．２ ｍ、７７１であり、距
離ｇは約０．１ ｆｉ ７７１である。FIG. 1 is a plan cross-sectional view showing an embodiment of the present invention, in which 1 is an inkjet head, 2 is a water-based ink having conductivity, 6 is a nozzle for ejecting the ink 2, and 4 is a nozzle facing the nozzle 3 at a distance. The first electrode 5 is placed a distance l apart from the first electrode 4, and the second electrode 5 is placed a distance g apart from the first electrode 4. distance 1
is 0.27Hfi to 1.2 m, 771, and the distance g is approximately 0.1 fi 771.
また電極４，５は黄銅に金メッキし、て作られる。Further, the electrodes 4 and 5 are made of gold-plated brass.
６は電極４，５を保持する合成樹脂製の電極基板で、電
極基板６と電極４，５はノズル３に対向する側が平滑な
平面に作られている。Reference numeral 6 denotes an electrode substrate made of synthetic resin that holds the electrodes 4 and 5, and the electrode substrate 6 and the electrodes 4 and 5 are made to have a smooth flat surface on the side facing the nozzle 3.
７はノズル３かも射出され電極基板６に到達したインク
滴で、８は電極基板６の表面を摺動するゴム製のワイパ
ーである。7 is an ink droplet ejected from the nozzle 3 and reaching the electrode substrate 6, and 8 is a rubber wiper that slides on the surface of the electrode substrate 6.
上記構成においてその動作を説明する。インク滴７がノ
ズル３から射出する前は、電極基板乙の表面にはインク
滴が存在せず、電極４，５間は非導通であり抵抗はほぼ
無限大とみなせる。インクジェットヘッド１の図示され
ていない圧電素子を駆動してノズル３からインク２を射
出すると、所定時間経過後インク滴７が電極４，５を導
通ずるように電極基板乙の表面に付着する。後に詳述す
る検出回路によシミ極４，５間の抵抗値変化を検出する
ことで、インク滴７の飛行状態の良、不良を検出し、不
良の場合は不良信号を発生するとともに、後に述べるヘ
ッド回復手段によりヘッドを回復し、再びインク滴７を
射出して飛行状態の良、不良を検出し、良となれば通常
の印字動作に入る。The operation of the above configuration will be explained. Before the ink droplet 7 is ejected from the nozzle 3, there is no ink droplet on the surface of the electrode substrate B, there is no conduction between the electrodes 4 and 5, and the resistance can be considered to be almost infinite. When a piezoelectric element (not shown) of the inkjet head 1 is driven to eject ink 2 from the nozzle 3, ink droplets 7 adhere to the surface of the electrode substrate B so that the electrodes 4 and 5 are electrically connected after a predetermined period of time. By detecting the change in resistance value between the stain electrodes 4 and 5 using a detection circuit, which will be described in detail later, it is possible to detect whether the flight condition of the ink droplet 7 is good or bad, and if it is defective, it will generate a defect signal and will notify you later. The head is recovered by the head recovery means described above, and the ink droplets 7 are ejected again to detect whether the flying condition is good or bad.If it is found to be good, normal printing operation begins.
数回の回復動作にもかかわらず良状態にならない場合に
は不良信号を表示して印刷装置を停止させる。ワイパー
８はインク滴７の有無の検出が終るたびに図示されてい
ない機構により電極基板６の表面を摺動し、インク滴７
をかき落して初期状態に戻り、次の検出にそなえる。If the printer is not in good condition despite several recovery operations, a defect signal is displayed and the printing device is stopped. The wiper 8 slides on the surface of the electrode substrate 6 by a mechanism (not shown) every time the presence or absence of the ink droplet 7 is detected.
Scrape it off to return to the initial state and prepare for the next detection.
第２図に第１図で説明した電極４，５間の抵抗値変化を
検出する検出回路を示す。１０は電圧コンパレータで入
力ｖ１は電源ｖｃ を抵抗Ｒ１：抵抗Ｒ２の比に分圧し
た電圧であり、入力ｖ２は電源ｖｃ を抵抗Ｒ３：抵抗
Ｒｉに分圧した電圧であ′る。FIG. 2 shows a detection circuit for detecting a change in resistance value between the electrodes 4 and 5 explained in FIG. 1. Reference numeral 10 denotes a voltage comparator, and input v1 is a voltage obtained by dividing the power source vc into a ratio of resistor R1:resistor R2, and input v2 is a voltage obtained by dividing power source vc into a ratio of resistor R3:resistor Ri.
Ｖｏ はコンパレータ１０の出力で電圧Ｖｔ と電圧
ｖ２の大小により出力が反転する。この例では、Ｖｃ
”’ ” Ｖｓ Ｒ１＝ Ｒ２＝ １０ Ｋ Ｄ 、Ｒ
ｓ＝２Ｋｇである。抵抗Ｒ１は電極４，５の間の抵抗値
であり、インク滴が付着していない時Ｒｉ ＝ω、付着
している時Ｒｉ＝ＩＫΩである。Vo is the output of the comparator 10, and the output is inverted depending on the magnitude of the voltage Vt and the voltage v2. In this example, Vc
"'" Vs R1= R2= 10 K D , R
s=2Kg. The resistance R1 is the resistance value between the electrodes 4 and 5, and when no ink droplet is attached, Ri=ω, and when it is attached, Ri=IKΩ.
以上の構成においてその動作を第３図で説明する。本実
施例ではヘッドの駆動はいわゆる引きうち法と称する駆
動方法を用いており、ヘッドの圧電素子にはＶｄで示す
電圧が印加される。すなわち直接的にヘッドの圧力室の
容積を小さくしてインクを射出するのではなく、一度圧
力室容積を増大させインクを圧力室内に供給した後、所
定の時間たった時刻Ｔ２に圧力室容積をもとに戻しイン
ク射出を行なう。ノズル６から射出されたインク滴７が
電極４，５に付着するとコンパレータ１０の入力電圧ｖ
２は電源ｖｃＯ値から、ＶｃＸＲａ／ＲｉＯ値まで下が
シ、時刻Ｔ３ に入力電圧Ｖｌ よシ下がる。その結
果コンパレータ１０の出力Ｖ 。The operation of the above configuration will be explained with reference to FIG. In this embodiment, the head is driven by a driving method called the so-called pulling method, and a voltage indicated by Vd is applied to the piezoelectric element of the head. That is, instead of directly reducing the volume of the pressure chamber of the head and ejecting ink, the pressure chamber volume is increased once, ink is supplied into the pressure chamber, and then the pressure chamber volume is increased at time T2 after a predetermined period of time. Return to the original position and perform ink ejection. When the ink droplet 7 ejected from the nozzle 6 adheres to the electrodes 4 and 5, the input voltage v of the comparator 10 increases.
2, the voltage decreases from the power supply vcO value to the VcXRa/RiO value, and at time T3, the input voltage Vl decreases. As a result, the output of comparator 10 is V.
は時刻Ｔ３に反転する。時刻Ｔ３とＴ２の間すなわち時
間ｔと、第１図に示した距離１１およびインク滴の飛行
速度υとの間には、およそυ＝１／ｌの関係がある。従
って時刻ｔを測定することによりインク飛行速度υが判
り、所定の速度以上ない場合にはインク飛行不良と判定
できる。例えば飛行速度υの下限をυＳとすると５ｔｓ
−ｔ／υ８であるような時間ｔｓ経過後もコンパレータ
出力ＶＯが反転しない場合には飛行不良と判定できる。is reversed at time T3. There is approximately a relationship of υ=1/l between time T3 and T2, that is, time t, and the distance 11 and the flight speed υ of the ink droplet shown in FIG. Therefore, by measuring the time t, the ink flight speed υ can be determined, and if the speed is less than a predetermined speed, it can be determined that the ink flight is defective. For example, if the lower limit of flight speed υ is υS, it is 5ts
If the comparator output VO does not invert even after the elapse of time ts, which is -t/υ8, it can be determined that the flight is defective.
具体的には％ １ ＝ １１ｒＬＴｒＬ、 ｖ 、＝
２７Ｈ／Ｓとすればｔｓ＝ｏ、ｓｎｓとなる。Specifically, % 1 = 11rLTrL, v , =
27H/S, ts=o, sns.
第４図は本発明の他の一実施例でマルチノズルヘッドに
対応したインク検出装置を示す。この例では電極基板乙
に、電極４−１ 、４−２ 、・・・４−９および、電
極５−１ 、５−２ 、・・・５−９が設けられている
。しかしながら電極４−１〜４−９および５−１〜５−
９は電極基板６の背面で各々導通がとられており、電気
的にはひと組の電極４および、電極５と見なせる。ヘッ
ド１には各々の電極と対応して９コのノズルが設けられ
ている。例えば４番目のノズルからインク滴７−４が射
出された時、電極４−４と電極５−４の間の抵抗値を検
出すれば、４番目のノズルからのインク飛行状態を検出
できる。第１図の実施例で示したようにインク飛行の有
無だけでなく、規格よりも遅く、従って印字品質の悪い
インク滴の検出ができる。FIG. 4 shows an ink detection device compatible with a multi-nozzle head, which is another embodiment of the present invention. In this example, electrodes 4-1, 4-2, . . . 4-9 and electrodes 5-1, 5-2, . . . 5-9 are provided on the electrode substrate B. However, electrodes 4-1 to 4-9 and 5-1 to 5-
9 are electrically connected to each other on the back surface of the electrode substrate 6, and can be electrically regarded as a pair of electrodes 4 and 5. The head 1 is provided with nine nozzles corresponding to each electrode. For example, when the ink droplet 7-4 is ejected from the fourth nozzle, the state of ink flight from the fourth nozzle can be detected by detecting the resistance value between the electrode 4-4 and the electrode 5-4. As shown in the embodiment of FIG. 1, it is possible not only to detect the presence or absence of ink flight, but also to detect ink droplets that are slower than the standard and therefore have poor print quality.
また本実施例ではインク飛行速度だけでなく、インク飛
行方向の不良も検出できる。すなわち正常なインク滴で
きりぎシ検出できるよう小面積の電極を、離れて配置し
であるため、５番目のノズルから射出されたインク滴７
−５は電極４−５に接触せず、従って不良と検出される
。もちろんインク滴７−５の飛行方向が極端に悪くなり
例えば電極４−６．５−６を導通させれば良と判定され
るが、速度検出と併用して検出すれば殆んど間違って判
定することはない。Furthermore, in this embodiment, not only the ink flying speed but also defects in the ink flying direction can be detected. In other words, since the small-area electrodes are spaced apart so that normal ink droplets can be detected, the ink droplet 7 ejected from the fifth nozzle
-5 does not contact the electrode 4-5 and is therefore detected as defective. Of course, if the flight direction of the ink droplet 7-5 becomes extremely bad, for example, if the electrode 4-6, 5-6 is made conductive, it will be judged as good, but if it is detected in conjunction with speed detection, it will almost always be judged incorrectly. There's nothing to do.
本実施例では電極４の系列と５の系列それぞれ導通をと
っているため検出回路としては第２図に示すもので良く
、たとえ２４ノズルのような多数のノズルのヘッドにも
ただひとつのコンパレータで良い。しかし前述したイン
ク飛行方向の厳密な判定のために個々の電極を独立させ
、各々のノズルに対応した電極の抵抗だけを検出するこ
ともできる。In this embodiment, conduction is established between the series of electrodes 4 and the series of electrodes 5, so the detection circuit shown in FIG. 2 may be sufficient. good. However, in order to accurately determine the direction of ink flight as described above, it is also possible to separate each electrode and detect only the resistance of the electrode corresponding to each nozzle.
本実施例ではノズルを順次駆動して時系列的に独立して
検出することでひとつでも飛行不良のノズルがあれは検
出し回復動作に入れる。なお順次検出する間に第１図に
示したワイパーでインク滴７を１回ずつきれいＫする必
要がある。In this embodiment, by sequentially driving the nozzles and independently detecting them in chronological order, if even one nozzle has a flight failure, it is detected and a recovery operation is initiated. Incidentally, during the sequential detection, it is necessary to wipe each ink droplet 7 once with the wiper shown in FIG.
第５図に本発明の他の実施例を示す。本実施例は片側８
ノズルが２列で１６ノズルに構成されたヘッドの検出を
示す。左側に１４−１〜１４−９の電極が配列され、右
側に１４−９〜１４−１７の電極が配列され、左側の電
極１４−９と右側の電極１４−９は連結され同一の電極
となっている。FIG. 5 shows another embodiment of the invention. In this example, one side has 8
Detection of a head configured with two rows of nozzles and 16 nozzles is shown. Electrodes 14-1 to 14-9 are arranged on the left side, electrodes 14-9 to 14-17 are arranged on the right side, and the left electrode 14-9 and the right electrode 14-9 are connected and are the same electrode. It has become.
電極１４−１と電極１４−１７が第２図の電極４と５に
相当する。この構成において、ノズルからインク滴１７
−１から１７−１６を同時に射出し、所定時間内にひと
つでも所定電極にインク滴が到達していなければ飛行不
良と判定する。この図ではインク滴１７−４が電極１４
−４と１４−５の間に付着しないため不良と判定される
。このように各インク滴の導通を直列的に検出すること
で、多数のノズルのインク飛行速度、方向を同時に瞬間
的に判定できる。本実施例の電極は約ｏ、ｚ＠＝ピッチ
で配列されているためセラミックを電極基板１６とし、
その上にスクリーン印刷で金電極を配置し、焼付けであ
る。Electrode 14-1 and electrode 14-17 correspond to electrodes 4 and 5 in FIG. In this configuration, the ink droplet 17 from the nozzle
-1 to 17-16 are simultaneously ejected, and if at least one ink droplet does not reach a predetermined electrode within a predetermined time, it is determined that there is a flight failure. In this figure, the ink droplet 17-4 is located on the electrode 14.
Since it does not adhere between -4 and 14-5, it is determined to be defective. By serially detecting the continuity of each ink droplet in this way, the ink flight speed and direction of a large number of nozzles can be determined simultaneously and instantaneously. Since the electrodes of this embodiment are arranged with a pitch of approximately o, z@=, ceramic is used as the electrode substrate 16,
A gold electrode is placed on top of it by screen printing and then baked.
本実施例のように各インク滴の有無を直列的に検出する
方法は、本実施例のように同時忙射出されたインク滴が
直接型ならないνスズかが複数列に配置されたヘッドに
好適であるが、たとえば縦１列ヘッドのように同時に各
ノズルを射出するとインク滴がつながってしまう場合は
、寄数ノズルのみ射出し、その後ヘッドを横方向に移動
しその場所で対向する次の電極群で直列的に検出するご
とく２度に分けることでほぼ同様な検出が可能である。The method of serially detecting the presence or absence of each ink droplet as in this embodiment is suitable for a head in which the ink droplets ejected at the same time do not form directly, and in which v-tin is arranged in multiple rows, as in this embodiment. However, if the ink droplets are connected when ejecting each nozzle at the same time, such as in a vertically single-row head, only the ink droplets are ejected from the ink droplets, and then the head is moved horizontally and the next electrode opposite to that location is ejected. Approximately similar detection is possible by dividing the detection into two stages, such as serial detection in groups.
以上述べた第４図、第５図の実施例では電極基板６，１
６とヘッド１との位置精度が重要であり、具体的には、
ヘッド１のノズル面の外形を基準として電極基板をなら
れせる機構、あるいは電極基板の位置調整機構が必要と
なる。In the embodiments shown in FIGS. 4 and 5 described above, the electrode substrates 6, 1
The positional accuracy between 6 and head 1 is important, and specifically,
A mechanism for aligning the electrode substrate with reference to the outer shape of the nozzle surface of the head 1 or a mechanism for adjusting the position of the electrode substrate is required.
第６図に本発明の他の実施例を示す。この例では電極基
板２６上に、電極２４．２５がインク滴にくらべ小さな
ピッチで相互に入り込むようにクシ形に配置されている
。従ってインク滴２７がどこについてもインク滴の有無
が検出でき、電極基板２６とヘッドとの位置合せ精度が
要求されない。FIG. 6 shows another embodiment of the invention. In this example, electrodes 24 and 25 are arranged in a comb shape on the electrode substrate 26 so as to interpenetrate each other at a smaller pitch than the ink droplets. Therefore, the presence or absence of an ink droplet 27 can be detected wherever the ink droplet 27 is located, and alignment accuracy between the electrode substrate 26 and the head is not required.
具体的にはインク滴２７の直径１５０μに対し電極２５
の縦方向のピッチｐは１００μ、くシ形の−１〇 −
横方向の巾Ｗは２ｍｍである。Specifically, the electrode 25 is
The pitch p in the vertical direction is 100μ, and the width W in the horizontal direction of the comb shape is 2 mm.
第７図に第６図の実施例をさらに発展させた実施例を示
す。この例では電極２５巾Ｗを２０ｍｆｉとし、４色の
ヘッド１−Ｙ、ｊ−Ｍ、１−Ｃ，１−Ｂに対しただひと
つの電極板２６で検出可能としている。FIG. 7 shows an embodiment that is a further development of the embodiment shown in FIG. In this example, the electrode 25 width W is set to 20 mfi, and only one electrode plate 26 can detect the four color heads 1-Y, j-M, 1-C, and 1-B.
第８図に第１図〜第７図と異る他の実施例を示す。３１
はインクジェットヘッド、３２は水性インク、３３はノ
ズル、５４はノズル３３と距離ｌ離して設けられた第１
の電極、３５はインク容器３６を結合する結合針で第２
の電極を兼ねる。電極３４．３５はステンレス鋼で作ら
れている。６７はノズル３３から射出されたインク柱で
あり、６８は電極５４の表面をきれいにするワイパーで
ある。FIG. 8 shows another embodiment different from those shown in FIGS. 1 to 7. 31
32 is an inkjet head, 32 is a water-based ink, 33 is a nozzle, and 54 is a first head provided at a distance l from the nozzle 33.
The second electrode 35 is a connecting needle that connects the ink container 36.
Also serves as an electrode. Electrodes 34,35 are made of stainless steel. 67 is a column of ink ejected from the nozzle 33, and 68 is a wiper for cleaning the surface of the electrode 54.
３９はインク容器３６のインクをヘッド３１に供給する
プラスチックチューブ、４０はプラスチックチューブ６
９内に発生した気泡であわ通常は存在しない。39 is a plastic tube that supplies ink from the ink container 36 to the head 31; 40 is a plastic tube 6;
9. Normally, there is no foam due to air bubbles generated within the container.
第８図の実施例において、電極５４．５５は第２図の検
出回路の電極４，５に相当する。しかしＲ２は約５００
Ｋｇと高くなり従ってＲ３も１ＭΩ程度にする必要があ
る。In the embodiment of FIG. 8, electrodes 54,55 correspond to electrodes 4, 5 of the detection circuit of FIG. But R2 is about 500
Kg, so R3 must also be about 1 MΩ.
第８図の実施例の動作を説明する前に、第９図により通
常のインクオンデマント型ヘッドのインク滴の飛行状態
を説明する。まずノズル３６から射出されたインク３７
はａ図のように柱状に飛行を始め、ヘッド内部が負圧に
なるにつれてｂ図のように細くくびれで切れ、０図のよ
うにインク表面張力によシ個々のインク滴に分かれて飛
行する１、次に第８図の動作を説明すると、まずヘッド
６１を駆動し、ノズル３３からインク柱３７を射出し、
インク柱６７が電極６４と接触した時の電極６４と６５
間の抵抗変化を検出する。検出波形としては第３図とほ
ぼ同様になる。ただし、コンパレータ１０の出力波形が
切れる時刻Ｔ４は、第９図すに示すように、インク柱３
７か細くくびれインク滴となった時刻となる。第１図で
説明したように第６図に示す時間ｔを測足することでイ
ンク柱６７の速度が判り、飛行の良悪が判定できる。Before explaining the operation of the embodiment shown in FIG. 8, the flying state of ink droplets in a normal ink-on-demand type head will be explained with reference to FIG. First, the ink 37 ejected from the nozzle 36
The ink begins to fly in a columnar shape as shown in figure a, and as the pressure inside the head becomes negative, it breaks into a narrow constriction as shown in figure b, and the ink separates into individual ink droplets and flies due to the ink surface tension as shown in figure 0. 1. Next, to explain the operation shown in FIG. 8, first, the head 61 is driven, the ink column 37 is ejected from the nozzle 33,
Electrodes 64 and 65 when ink column 67 contacts electrode 64
Detects resistance changes between The detected waveform is almost the same as that shown in FIG. However, the time T4 when the output waveform of the comparator 10 is cut off is as shown in FIG.
This is the time when the ink droplets become thin and constricted. As explained in FIG. 1, by measuring the time t shown in FIG. 6, the speed of the ink column 67 can be determined, and the quality of the flight can be determined.
本実施例では例えば第８図に示すような気泡４０がチュ
ーブ４０内に存在した場合、インク柱３７が電極５４に
正常に導通しても気泡４０で電気的導通がとれず不良と
判断される。したがってヘッド３１が射出不良となる前
に将来ヘッドに流入して射出不良となる気泡を前もって
検出できる。In this embodiment, for example, if a bubble 40 as shown in FIG. 8 exists in the tube 40, even if the ink column 37 is normally connected to the electrode 54, the bubble 40 prevents electrical continuity and it is determined to be defective. . Therefore, before the head 31 becomes defective in ejection, it is possible to detect air bubbles that will flow into the head in the future and cause defective ejection.
本実施例では距離ｌは２００μから４００μ程度に選ば
れる。２００μ以下であると検出感度が下がシ飛行速度
の早いものと遅いものの区別がしにくくなる。また４０
０μ以上だとインク柱が切れてから電極３．４に到達す
る距離となり検出ができなくなる。In this embodiment, the distance l is selected to be approximately 200μ to 400μ. If it is less than 200μ, the detection sensitivity will be low and it will be difficult to distinguish between fast and slow flight speeds. 40 again
If it is 0μ or more, the distance from the ink column being cut to reaching the electrode 3.4 makes detection impossible.
第１０図に第８図の実施例をマルチノズルに応用した実
施例を示す。第８図と異なるのはノズルが３３−１〜３
５−４まで４ノズルあること、電極３５がヘッド内に設
けられていること、またノズルとめ゛距離、１ｔ、正確
に出すための電極３４の両端に度決め４２が設けられ、
レバー４３を介してバネ４４により電極３４はヘッド３
１に回動可能に押しつけられている。FIG. 10 shows an example in which the embodiment shown in FIG. 8 is applied to a multi-nozzle. The difference from Figure 8 is that the nozzles are 33-1 to 3.
There are 4 nozzles up to 5-4, the electrode 35 is provided in the head, the target distance from the nozzle is 1t, and there are measuring holes 42 at both ends of the electrode 34 for accurate discharge.
The electrode 34 is connected to the head 3 by a spring 44 via a lever 43.
1 is rotatably pressed.
駆動はノズル５３−４から３３−１に向かって下から順
々に行なわれる。各ノズル毎に導通の後非導通の状態が
くるため、電極６４上にインクが残っていても独立して
順々に検出が可能である。The driving is performed sequentially from the bottom toward the nozzles 53-4 to 33-1. Since each nozzle becomes conductive and then non-conductive, even if ink remains on the electrode 64, it can be detected independently and sequentially.
また下から検出して行くためインクが流れ下りてもその
上側の検出には悪影響がない。３３−１′！ｉで検出が
終った時点で、レバー４３は図示されていないカムによ
りヘッド３１から離され、スポンジ製のロール状のワイ
パー３８が下りて来て電極６４表面のインク滴をきれい
にして次の検出にそなえる。Furthermore, since detection is performed from below, even if ink flows down, there is no adverse effect on detection above it. 33-1′! When the detection is completed at step i, the lever 43 is separated from the head 31 by a cam (not shown), and the sponge roll-shaped wiper 38 comes down to clean the ink droplets on the surface of the electrode 64 and perform the next detection. Prepare for.
なおこの例では度決め４２を電極３４に設けているが、
ヘッド５１のノズル面の外周部処凸部を設けてこれを度
決めとし電極６４を平面にしても良い。このようにすれ
ば、電極６４０表面のインクはふき取シやすくなシ、度
決め部が紙とノズル面との接触によるノズルの故障の防
止手段にもなる。Note that in this example, the degree setting 42 is provided on the electrode 34,
A convex portion may be provided on the outer periphery of the nozzle surface of the head 51 to determine the degree, and the electrode 64 may be made flat. In this way, the ink on the surface of the electrode 640 can be easily wiped off, and the measuring section also serves as a means to prevent nozzle failure due to contact between the paper and the nozzle surface.
以上述べたように本発明によれば、少なくとも一方がノ
ズルと対向した位置に設けられた電極によりインク滴の
有無を抵抗値の変化として検出するため、機械的にも電
気的にも極めて簡単な構成ですむ。また電極の形状、配
置を適当に設定すれば、インクの飛行速度だけでなく、
飛行方向の検出も可能である。またマルチノズルヘッド
に対しても検出回路の増加をおさえることが可能であり
、シリアルプリンタ、ラインプリンタ、プロッタ、ファ
クシミリ等広く応用できる。また熱によりインクに圧力
を与えるサーマルインクジェットにも用いることができ
る。As described above, according to the present invention, the presence or absence of ink droplets is detected as a change in resistance value using an electrode, at least one of which is provided at a position facing the nozzle. Configuration is enough. In addition, by appropriately setting the shape and arrangement of the electrodes, you can increase not only the flight speed of the ink, but also the
Detection of flight direction is also possible. Furthermore, it is possible to suppress the increase in the number of detection circuits for multi-nozzle heads, and the present invention can be widely applied to serial printers, line printers, plotters, facsimiles, etc. It can also be used in thermal inkjet, which applies pressure to ink using heat.
第１図は本発明の一実施例を示す平断面図、第２図は第
１図の実施例に用いられる検出回路図、第３図は第１図
の実施例のタイミング線図、第４図は本発明の他の実施
例を示す要部斜視図、第５図は本発明の他の実施例の電
極基板の正面図、第６図は本発明のさらに他の実施例の
電極基板の正面図、第７図は第６図の実施例をカラーヘ
ッドに応用した場合の要部平面図、第８図は第１図〜第
７図と異なる本発明の他の実施例を示す要部側断面図、
第９図は第８図の実施例を説明するための側面図、第１
０図は第８図の実施例を発展させマルチノズルに応用し
た実施例を示す要部側面図を示す。
１．１−Ｙ、１−Ｍ、１−Ｃ，１−Ｂ、３１・・・ヘッ
ド
３．５３・・・ノズル
４．５．１４，２４，２５，３４．３５ ・・・電極
７．１７．２７・・・インク滴
３７・・・インク柱
以上1 is a plan sectional view showing an embodiment of the present invention, FIG. 2 is a detection circuit diagram used in the embodiment of FIG. 1, FIG. 3 is a timing diagram of the embodiment of FIG. 1, and FIG. 5 is a front view of an electrode substrate according to another embodiment of the present invention, and FIG. 6 is a front view of an electrode substrate according to another embodiment of the present invention. A front view, FIG. 7 is a plan view of the main part when the embodiment of FIG. 6 is applied to a color head, and FIG. 8 is a main part showing another embodiment of the present invention which is different from FIGS. 1 to 7. side sectional view,
FIG. 9 is a side view for explaining the embodiment shown in FIG.
FIG. 0 shows a side view of essential parts showing an embodiment in which the embodiment shown in FIG. 8 is developed and applied to a multi-nozzle. 1.1-Y, 1-M, 1-C, 1-B, 31... Head 3.53... Nozzle 4.5.14, 24, 25, 34.35... Electrode 7.17 .27...Ink drop 37...More than ink column
Claims (1)
有し、すくなくともそのひとつはインクを射出するノズ
ルから所定距離離れて対向配置された第１の電極であり
、前記ノズルから射出された導電性を有するインクが前
記第１の電極に到達した時の前記第１の電極と、他の電
極間の抵抗値の変化を検出することを特徴とするインク
滴検出装置。The ink-on-demand printing device has a plurality of electrodes, at least one of which is a first electrode disposed facing a predetermined distance from a nozzle that ejects ink, and has conductivity ejected from the nozzle. An ink droplet detection device that detects a change in resistance between the first electrode and another electrode when ink reaches the first electrode.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60228315A JP2724998B2 (en) | 1985-10-14 | 1985-10-14 | Ink drop detector |
| DE3634034A DE3634034C2 (en) | 1985-10-09 | 1986-10-06 | Ink detector for an inkjet printer |
| US06/917,641 US4768045A (en) | 1985-10-09 | 1986-10-09 | Ink droplet detecting apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60228315A JP2724998B2 (en) | 1985-10-14 | 1985-10-14 | Ink drop detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6287357A true JPS6287357A (en) | 1987-04-21 |
| JP2724998B2 JP2724998B2 (en) | 1998-03-09 |
Family
ID=16874514
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60228315A Expired - Lifetime JP2724998B2 (en) | 1985-10-09 | 1985-10-14 | Ink drop detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2724998B2 (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01297253A (en) * | 1988-05-25 | 1989-11-30 | Canon Inc | Ink jet recording apparatus |
| JPH02198847A (en) * | 1989-01-27 | 1990-08-07 | Canon Inc | Liquid injection recorder |
| JPH04115398U (en) * | 1991-03-27 | 1992-10-13 | シヤープ株式会社 | flash memory |
| EP0771655A3 (en) * | 1995-10-31 | 1998-09-16 | SCITEX DIGITAL PRINTING, Inc. | Short detection circuit for ink jet printer |
| JP2014097642A (en) * | 2012-11-15 | 2014-05-29 | Ricoh Co Ltd | Image forming apparatus |
| JP2015047853A (en) * | 2013-09-04 | 2015-03-16 | 株式会社リコー | Image forming apparatus and ejection detecting device |
| JP2015074106A (en) * | 2013-10-07 | 2015-04-20 | 株式会社リコー | Image formation device |
| JP2015164793A (en) * | 2014-02-04 | 2015-09-17 | 株式会社リコー | Image formation device, discharge detection unit, and liquid discharge device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60206660A (en) * | 1984-03-31 | 1985-10-18 | Canon Inc | Liquid jet recording device |
-
1985
- 1985-10-14 JP JP60228315A patent/JP2724998B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60206660A (en) * | 1984-03-31 | 1985-10-18 | Canon Inc | Liquid jet recording device |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01297253A (en) * | 1988-05-25 | 1989-11-30 | Canon Inc | Ink jet recording apparatus |
| JPH02198847A (en) * | 1989-01-27 | 1990-08-07 | Canon Inc | Liquid injection recorder |
| JPH04115398U (en) * | 1991-03-27 | 1992-10-13 | シヤープ株式会社 | flash memory |
| EP0771655A3 (en) * | 1995-10-31 | 1998-09-16 | SCITEX DIGITAL PRINTING, Inc. | Short detection circuit for ink jet printer |
| JP2014097642A (en) * | 2012-11-15 | 2014-05-29 | Ricoh Co Ltd | Image forming apparatus |
| JP2015047853A (en) * | 2013-09-04 | 2015-03-16 | 株式会社リコー | Image forming apparatus and ejection detecting device |
| JP2015074106A (en) * | 2013-10-07 | 2015-04-20 | 株式会社リコー | Image formation device |
| JP2015164793A (en) * | 2014-02-04 | 2015-09-17 | 株式会社リコー | Image formation device, discharge detection unit, and liquid discharge device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2724998B2 (en) | 1998-03-09 |
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| EXPY | Cancellation because of completion of term |