JP3804401B2 - Liquid consumption detection method and recording apparatus control method - Google Patents

Description

式２および式３より、図２１（Ａ)は、図２１（Ｂ)のように表すこともできる。
【０１０６】
コンプライアンスＣactは、振動部の単位面積に圧力をかけたときの変形によって媒体を受容できる体積を表す。また、コンプライアンスＣactは、変形のし易さを表すといってもよい。
【０１０７】
図２１（Ｃ)は、液体容器に液体が十分に収容され、アクチュエータ１０６の振動領域の周辺に液体が満たされている場合のアクチュエータ１０６の断面図を示す。図２１（Ｃ)のＭ’maxは、液体容器に液体が十分に収容され、アクチュエータ１０６の振動領域の周辺に液体が満たされている場合の付加イナータンスの最大値を表す。Ｍ’ maxは、
【０１０８】
Ｍ’max＝(π*ρ/(2*k³))*(2*(2*k*a)³/(3*π))/(π*a²)² （式４）
（ａは振動部の半径、ρは媒体の密度、ｋは波数である。）
【０１０９】
で表される。尚、式４は、アクチュエータ１０６の振動領域が半径ａの円形である場合に成立する。付加イナータンスＭ’は、振動部の付近にある媒体の作用によって、振動部の質量が見かけ上増加していることを示す量である。式４からわかるように、Ｍ’maxは振動部の半径ａと、媒体の密度ρとによって大きく変化する。
【０１１０】
波数kは、
ｋ＝２＊π＊ｆact／ｃ （式５）
（factは液体が触れていないときの振動部の共振周波数である。cは媒体中を伝播する音響の速度である。）
【０１１１】
で表される。
【０１１２】
図２１（Ｄ)は、液体容器に液体が十分に収容され、アクチュエータ１０６の振動領域の周辺に液体が満たされている図２１（Ｃ)の場合のアクチュエータ１０６の振動部およびキャビティ１６２の等価回路を示す。
【０１１３】
図２１（Ｅ)は、液体容器の液体が消費され、アクチュエータ１０６の振動領域の周辺に液体が無いものの、アクチュエータ１０６のキャビティ１６２内には液体が残存している場合のアクチュエータ１０６の断面図を示す。式４は、例えば、液体容器に液体が満たされている場合に、インクの密度ρなどから決定される最大のイナータンスＭ’maxを表す式である。一方、液体容器内の液体が消費され、キャビティ１６２内に液体が残留しつつアクチュエータ１０６の振動領域の周辺にある液体が気体または真空になった場合には、
【０１１４】
Ｍ’＝ρ*ｔ/Ｓ （式６）
と表せる。ｔは、振動にかかわる媒体の厚さである。Ｓは、アクチュエータ１０６の振動領域の面積である。この振動領域が半径ａの円形の場合は、Ｓ＝π*ａ²である。従って、付加イナータンスＭ’は、液体容器に液体が十分に収容され、アクチュエータ１０６の振動領域の周辺に液体が満たされている場合には、式４に従う。一方で、液体が消費され、キャビティ１６２内に液体が残留しつつアクチュエータ１０６の振動領域の周辺にある液体が気体または真空になった場合には、式６に従う。
【０１１５】
ここで、図２１（Ｅ)のように、液体容器の液体が消費され、アクチュエータ１０６の振動領域の周辺に液体が無いものの、アクチュエータ１０６のキャビティ１６２内には液体が残存している場合の付加イナータンスＭ’を便宜的にＭ’cavとし、アクチュエータ１０６の振動領域の周辺に液体が満たされている場合の付加イナータンスＭ’maxと区別する。
【０１１６】
図２１（Ｆ)は、液体容器の液体が消費され、アクチュエータ１０６の振動領域の周辺に液体が無いものの、アクチュエータ１０６のキャビティ１６２内には液体が残存している図２１（Ｅ)の場合のアクチュエータ１０６の振動部およびキャビティ１６２の等価回路を示す。
【０１１７】
ここで、媒体の状態に関係するパラメータは、式６において、媒体の密度ρおよび媒体の厚さｔである。液体容器内に液体が充分に収容されている場合は、アクチュエータ１０６の振動部に液体が接触し、液体容器内に液体が充分に収容されていない場合は、キャビティ内部に液体が残存するか、もしくはアクチュエータ１０６の振動部に気体または真空が接触する。アクチュエータ１０６の周辺の液体が消費され、図２１（Ｃ)のＭ’maxから図２１（Ｅ)のＭ’cavへ移行する過程における付加イナータンスをＭ’ varとすると、液体容器内の液体の収容状態によって、媒体の厚さｔが変化するため、付加イナータンスＭ’varが変化し、共振周波数ｆｓも変化することになる。従って、共振周波数ｆｓを特定することによって、液体容器内の液体の有無を検出することができる。ここで、図２１(Ｅ)に示すようにｔ＝ｄとした場合、式６を用いてＭ’cavを表すと、式６のｔにキャビティの深さｄを代入し、
【０１１８】
Ｍ’cav＝ρ*ｄ/Ｓ （式７）
となる。
【０１１９】
また、媒体が互いに種類の異なる液体であっても、組成の違いによって密度ρが異なるため、付加イナータンスＭ´が変化し、共振周波数ｆｓも変化する。従って、共振周波数ｆｓを特定することで、液体の種類を検出できる。
尚、アクチュエータ１０６の振動部にインクまたは空気のいずれか一方のみが接触し、混在していない場合には、式４によって計算しても、Ｍ’の相違を検出できる。
【０１２０】
図２２（Ａ）は、インクタンク内のインクの量とインクおよび振動部の共振周波数ｆｓとの関係を示すグラフである。ここでは液体の１例としてインクについて説明する。縦軸は、共振周波数ｆｓを示し、横軸は、インク量を示す。インク組成が一定であるとき、インク残量の低下に伴い、共振周波数ｆｓは、上昇する。
【０１２１】
インク容器にインクが十分に収容され、アクチュエータ１０６の振動領域の周辺にインクが満たされている場合には、その最大付加イナータンスＭ’maxは式４に表わされる値となる。一方で、インクが消費され、キャビティ１６２内に液体が残留しつつアクチュエータ１０６の振動領域の周辺にインクが満たされていないときには、付加イナータンスＭ’varは、媒体の厚さｔに基づいて式６によって算出される。式６中のｔは振動にかかわる媒体の厚さであるから、アクチュエータ１０６のキャビティ１６２のｄ(図２０（Ｂ）参照)を小さく、即ち、基板１７８を十分に薄くすることによって、インクが徐々に消費されていく過程を検出することもできる（図２１（Ｃ)参照）。ここで、ｔinkは振動にかかわるインクの厚さとし、ｔink−maxはＭ’maxにおけるｔinkとする。例えば、インクカートリッジの底面にアクチュエータ１０６をインクの液面に対してほぼ水平に配備する。インクが消費され、インクの液面がアクチュエータ１０６からｔink-maxの高さ以下に達すると、式６によりＭ’varが徐々に変化し、式１により共振周波数ｆｓが徐々に変化する。従って、インクの液面がｔの範囲内にある限り、アクチュエータ１０６はインクの消費状態を徐々に検出することができる。
【０１２２】
また、アクチュエータ１０６の振動領域を大きくまたは長くし、かつ縦に配置することによってインクの消費による液面の位置にしたがって、式６中のＳが変化する。従って、アクチュエータ１０６はインクが徐々に消費されていく過程を検出することもできる。例えば、インクカートリッジの側壁にアクチュエータ１０６をインクの液面に対してほぼ垂直に配備する。インクが消費され、インクの液面がアクチュエータ１０６の振動領域に達すると、水位の低下に伴い付加イナータンスＭ’が減少するので、式１により共振周波数ｆｓが徐々に増加する。従って、インクの液面が、キャビティ１６２の径２ａ（図２１（Ｃ)参照）の範囲内にある限り、アクチュエータ１０６はインクの消費状態を徐々に検出することができる。
【０１２３】
図２２(Ａ)の曲線Ｘは、アクチュエータ１０６のキャビティ１６２を十分に浅くした場合や、アクチュエータ１０６の振動領域を十分に大きくまたは長くした場合のインクタンク内に収容されたインクの量とインクおよび振動部の共振周波数ｆｓとの関係を表わしている。インクタンク内のインクの量が減少するとともに、インクおよび振動部の共振周波数ｆｓが徐々に変化していく様子が理解できる。
【０１２４】
より詳細には、インクが徐々に消費されていく過程を検出することができる場合とは、アクチュエータ１０６の振動領域の周辺において、互いに密度が異なる液体と気体とがともに存在し、かつ振動にかかわる場合である。インクが徐々に消費されていくに従って、アクチュエータ１０６の振動領域周辺において振動にかかわる媒体は、液体が減少する一方で気体が増加する。例えば、アクチュエータ１０６をインクの液面に対して水平に配備した場合であって、ｔinkがｔink−maxより小さいときには、アクチュエータ１０６の振動にかかわる媒体はインクと気体との両方を含む。したがって、アクチュエータ１０６の振動領域の面積Ｓとすると、式４のＭ’max以下になった状態をインクと気体の付加質量で表すと、
【０１２５】
Ｍ’＝Ｍ’air＋Ｍ’ink＝ ρair*ｔair/Ｓ+ρink*ｔink/Ｓ （式８）
となる。ここで、Ｍ’airは空気のイナータンスであり、Ｍ’inkはインクのイナータンスである。ρairは空気の密度であり、ρinkはインクの密度である。ｔairは振動にかかわる空気の厚さであり、ｔinkは振動にかかわるインクの厚さである。アクチュエータ１０６の振動領域周辺における振動にかかわる媒体のうち、液体が減少して気体が増加するに従い、アクチュエータ１０６がインクの液面に対しほぼ水平に配備されている場合には、ｔairが増加し、ｔinkが減少する。それによって、Ｍ’varが徐々に減少し、共振周波数が徐々に増加する。よって、インクタンク内に残存しているインクの量またはインクの消費量を検出することができる。尚、式７において液体の密度のみの式となっているのは、液体の密度に対して、空気の密度が無視できるほど小さい場合を想定しているからである。
【０１２６】
アクチュエータ１０６がインクの液面に対しほぼ垂直に配備されている場合には、アクチュエータ１０６の振動領域のうち、アクチュエータ１０６の振動にかかわる媒体がインクのみの領域と、アクチュエータ１０６の振動にかかわる媒体が気体の領域との並列の等価回路（図示せず）と考えられる。アクチュエータ１０６の振動にかかわる媒体がインクのみの領域の面積をＳinkとし、アクチュエータ１０６の振動にかかわる媒体が気体のみの領域の面積をＳairとすると、
【０１２７】

となる。
【０１２８】
尚、式９は、アクチュエータ１０６のキャビティにインクが保持されない場合に適用される。アクチュエータ１０６のキャビティにインクが保持される場合については、式７、式８および式９によって計算することができる。
【０１２９】
一方、基板１７８が厚く、即ち、キャビティ１６２の深さｄが深く、ｄが媒体の厚さｔink-maxに比較的近い場合や、液体容器の高さに比して振動領域が非常に小さいアクチュエータを用いる場合には、実際上はインクが徐々に減少する過程を検出するというよりはインクの液面がアクチュエータの装着位置より上位置か下位置かを検出することになる。換言すると、アクチュエータの振動領域におけるインクの有無を検出することになる。例えば、図２２(Ａ)の曲線Ｙは、小さい円形の振動領域の場合におけるインクタンク内のインクの量とインクおよび振動部の共振周波数ｆｓとの関係を示す。インクタンク内のインクの液面がアクチュエータの装着位置を通過する前後におけるインク量Ｑの間で、インクおよび振動部の共振周波数ｆｓが激しく変化している様子が示される。このことから、インクタンク内にインクが所定量残存しているか否かを検出することができる。
【０１３０】
図２２（Ｂ）は、図２２（Ａ）の曲線Ｙにおけるインクの密度とインクおよび振動部の共振周波数ｆｓとの関係を示す。液体の例としてインクを挙げている。図２２（Ｂ）に示すように、インク密度が高くなると、付加イナータンスが大きくなるので共振周波数ｆｓが低下する。すなわち、インクの種類によって共振周波数ｆｓが異なる。したがって共振周波数ｆｓを測定することによって、インクを再充填する際に、密度の異なったインクが混入されていないか確認することができる。
【０１３１】
つまり、互いに種類の異なるインクを収容するインクタンクを識別できる。
【０１３２】
続いて、液体容器内の液体が空の状態であってもアクチュエータ１０６のキャビティ１６２内に液体が残存するようにキャビティのサイズと形状を設定した時の、液体の状態を正確に検出できる条件を詳述する。アクチュエータ１０６は、キャビティ１６２内に液体が満たされている場合に液体の状態を検出できれば、キャビティ１６２内に液体が満たされていない場合であっても液体の状態を検出できる。
【０１３３】
共振周波数ｆｓは、イナータンスＭの関数である。イナータンスＭは、振動部のイナータンスＭactと付加イナータンスＭ’との和である。ここで、付加イナータンスＭ’が液体の状態と関係する。付加イナータンスＭ’は、振動部の付近にある媒体の作用によって振動部の質量が見かけ上増加していることを示す量である。即ち、振動部の振動によって見かけ上媒体を吸収することによる振動部の質量の増加分をいう。
【０１３４】
従って、Ｍ’cavが式４におけるＭ’maxよりも大きい場合には、見かけ上吸収する媒体は全てキャビティ１６２内に残存する液体である。よって、液体容器内に液体が満たされている状態と同じである。この場合にはＭ’が変化しないので、共振周波数ｆｓも変化しない。従って、アクチュエータ１０６は、液体容器内の液体の状態を検出できないことになる。
【０１３５】
一方、Ｍ’cavが式４におけるＭ’ maxよりも小さい場合には、見かけ上吸収する媒体はキャビティ１６２内に残存する液体および液体容器内の気体または真空である。このときには液体容器内に液体が満たされている状態とは異なりＭ’が変化するので、共振周波数ｆｓが変化する。従って、アクチュエータ１０６は、液体容器内の液体の状態を検出できる。
【０１３６】
即ち、液体容器内の液体が空の状態で、アクチュエータ１０６のキャビティ１６２内に液体が残存する場合に、アクチュエータ１０６が液体の状態を正確に検出できる条件は、Ｍ’cavがＭ’maxよりも小さいことである。尚、アクチュエータ１０６が液体の状態を正確に検出できる条件Ｍ’max＞Ｍ’cavは、キャビティ１６２の形状にかかわらない。
【０１３７】
ここで、Ｍ’cavは、キャビティ１６２の容量とほぼ等しい容量の液体の質量である。従って、Ｍ’max＞Ｍ’cavの不等式から、アクチュエータ１０６が液体の状態を正確に検出できる条件は、キャビティ１６２の容量の条件として表すことができる。例えば、円形状のキャビティ１６２の開口１６１の半径をaとし、およびキャビティ１６２の深さをｄとすると、
【０１３８】
Ｍ’max＞ρ＊ｄ/πa² （式１０）
である。式１０を展開すると
【０１３９】
ａ／ｄ＞３＊π／８ （式１１）
という条件が求められる。尚、式１０、式１１は、キャビティ１６２の形状が円形の場合に限り成立する。円形でない場合のＭ’maxの式を用い、式１０中のπa²をその面積と置き換えて計算すれば、キャビティの幅および長さ等のディメンジョンと深さの関係が導き出せる。
【０１４０】
従って、式１１を満たす開口１６１の半径aおよびキャビティ１６２の深さｄであるキャビティ１６２を有するアクチュエータ１０６であれば、液体容器内の液体が空の状態であって、かつキャビティ１６２内に液体が残存する場合であっても、誤作動することなく液体の状態を検出できる。
【０１４１】
付加イナータンスＭ’は音響インピーダンス特性にも影響するので、残留振動によりアクチュエータ１０６に発生する逆起電力を測定する方法は、少なくとも音響インピーダンスの変化を検出しているともいえる。
【０１４２】
また、本実施例によれば、アクチュエータ１０６が振動を発生してその後の残留振動によりアクチュエータ１０６に発生する逆起電力を測定している。しかし、アクチュエータ１０６の振動部が駆動電圧による自らの振動によって液体に振動を与えることは必ずしも必要ではない。即ち、振動部が自ら発振しなくても、それと接触しているある範囲の液体と共に振動することで、圧電層１６０がたわみ変形する。この残留振動が圧電層１６０に逆起電力電圧を発生させ、上部電極１６４および下部電極１６６にその逆起電力電圧を伝達する。この現象を利用することで媒体の状態を検出してもよい。例えば、インクジェット記録装置において、印字時における印字ヘッドの走査によるキャリッジの往復運動による振動によって発生するアクチュエータの振動部の周囲の振動を利用してインクタンクまたはその内部のインクの状態を検出してもよい。
【０１４３】
図２３(Ａ) および図２３（Ｂ）は、アクチュエータ１０６を振動させた後の、アクチュエータ１０６の残留振動の波形と残留振動の測定方法とを示す。インクカートリッジ内のアクチュエータ１０６の装着位置レベルにおけるインク水位の上下は、アクチュエータ１０６が発振した後の残留振動の周波数変化や、振幅の変化によって検出することができる。図２３(Ａ) および図２３（Ｂ）において、縦軸はアクチュエータ１０６の残留振動によって発生した逆起電力の電圧を示し、横軸は時間を示す。アクチュエータ１０６の残留振動によって、図２３(Ａ) および図２３（Ｂ）に示すように電圧のアナログ信号の波形が発生する。次に、アナログ信号を、信号の周波数に対応するデジタル数値に変換する。
【０１４４】
図２３(Ａ)および図２３（Ｂ）に示した例においては、アナログ信号の４パルス目から８パルス目までの４個のパルスが生じる時間を計測することによって、インクの有無を検出する。
【０１４５】
より詳細には、アクチュエータ１０６が発振した後、予め設定された所定の基準電圧を低電圧側から高電圧側へ横切る回数をカウントする。デジタル信号を４カウントから８カウントまでの間をＨｉｇｈとし、所定のクロックパルスによって４カウントから８カウントまでの時間を計測する。
【０１４６】
図２３（Ａ）はアクチュエータ１０６の装着位置レベルよりも上位にインク液面があるときの波形である。一方、図２３（Ｂ）はアクチュエータ１０６の装着位置レベルにおいてインクが無いときの波形である。図２３（Ａ）と図２３（Ｂ）とを比較すると、図２３（Ａ）の方が図２３（Ｂ）よりも４カウントから８カウントまでの時間が長いことがわかる。換言すると、インクの有無によって４カウントから８カウントまでの時間が異なる。この時間の相違を利用して、インクの消費状態を検出することができる。アナログ波形の４カウント目から数えるのは、アクチュエータ１０６の振動が安定してから計測をはじめるためである。４カウント目からとしたのは単なる一例であって、任意のカウントから数えてもよい。ここでは、４カウント目から８カウント目までの信号を検出し、所定のクロックパルスによって４カウント目から８カウント目までの時間を測定する。それによって、共振周波数を求める。クロックパルスは、インクカートリッジに取り付けられる半導体記憶装置等を制御するためのクロックと等しいクロックのパルスであることが好ましい。尚、８カウント目までの時間を測定する必要は無く、任意のカウントまで数えてもよい。図２３においては、４カウント目から８カウント目までの時間を測定しているが周波数を検出する回路構成にしたがって、異なったカウント間隔内の時間を検出してもよい。
【０１４７】
例えば、インクの品質が安定していてピークの振幅の変動が小さい場合には、検出の速度を上げるために４カウント目から６カウント目までの時間を検出することにより共振周波数を求めてもよい。また、インクの品質が不安定でパルスの振幅の変動が大きい場合には、残留振動を正確に検出するために４カウント目から１２カウント目までの時間を検出してもよい。
【０１４８】
また、他の実施例として所定期間内における逆起電力の電圧波形の波数を数えてもよい（図示せず）。この方法によっても共振周波数を求めることができる。より詳細には、アクチュエータ１０６が発振した後、所定期間だけデジタル信号をＨｉｇｈとし、所定の基準電圧を低電圧側から高電圧側へ横切る回数をカウントする。そのカウント数を計測することによってインクの有無を検出できるのである。
【０１４９】
さらに、図２３(Ａ)および図２３(Ｂ)を比較して分かるように、インクがインクカートリッジ内に満たされている場合とインクがインクカートリッジ内に無い場合とでは、逆起電力波形の振幅が異なる。従って、共振周波数を求めることなく、逆起電力波形の振幅を測定することによっても、インクカートリッジ内のインクの消費状態を検出してもよい。より詳細には、例えば、図２３(Ａ)の逆起電力波形の頂点と図２３(Ｂ) の逆起電力波形の頂点との間に基準電圧を設定する。アクチュエータ１０６が発振した後、所定時間にデジタル信号をＨｉｇｈとし、逆起電力波形が基準電圧を横切った場合には、インクが無いと判断する。逆起電力波形が基準電圧を横切らない場合には、インクが有ると判断する。
【０１５０】
図２４は、アクチュエータ１０６の製造方法を示す。複数のアクチュエータ１０６（図２４の例では４個）が一体に形成されている。図２４に示した複数のアクチュエータの一体成形物を、それぞれのアクチュエータ１０６において切断することにより、図２５に示すアクチュエータ１０６を製造する。図２４に示す一体成形された複数のアクチュエータ１０６のそれぞれの圧電素子が円形である場合、一体成形物をそれぞれのアクチュエータ１０６において切断することにより、図２０に示すアクチュエータ１０６を製造することができる。複数のアクチュエータ１０６を一体に形成することにより、複数のアクチュエータ１０６を同時に効率良く製造することができ、運搬時の取り扱いが容易となる。
【０１５１】
アクチュエータ１０６は、薄板又は振動板１７６、基板１７８、弾性波発生手段又は圧電素子１７４、端子形成部材又は上部電極端子１６８、及び端子形成部材又は下部電極端子１７０を有する。圧電素子１７４は、圧電振動板又は圧電層１６０、上電極又は上部電極１６４、及び下電極又は下部電極１６６を含む。基板１７８の上面に振動板１７６が、形成され、振動板１７６の上面に下部電極１６６が形成されている。下部電極１６６の上面には、圧電層１６０が形成され、圧電層１６０の上面に、上部電極１６４が、形成されている。したがって、圧電層１６０の主要部は、上部電極１６４の主要部及び下部電極１６６の主要部によって、上下から挟まれるように形成されている。
【０１５２】
振動板１７６上に複数（図２４の例では４個）の圧電素子１７４が形成されている。振動板１７６の表面に下部電極１６６が形成され、下部電極１６６の表面に圧電層１６０が形成され、圧電層１６０の上面に上部電極１６４が形成される。上部電極１６４及び下部電極１６６の端部に上部電極端子１６８及び下部電極端子１７０が形成される。４個のアクチュエータ１０６は、それぞれ別々に切断されて個別に使用される。
【０１５３】
図２５は、圧電素子が矩形のアクチュエータ１０６の一部分の断面を示す。
【０１５４】
図２６は、図２５に示したアクチュエータ１０６の全体の断面を示す。基板１７８の圧電素子１７４と対向する面には、貫通孔１７８ａが形成されている。貫通孔１７８ａは振動板１７６によって封止されている。振動板１７６はアルミナや酸化ジルコニア等の電気絶縁性を備え、かつ弾性変形可能な材料によって形成されている。貫通孔１７８ａと対向するように、圧電素子１７４が振動板１７６上に形成されている。下部電極１６６は貫通孔１７８ａの領域から一方向、図２６では左方に延びるように振動板１７６の表面に形成されている。上部電極１６４は貫通孔１７８ａの領域から下部電極とは反対の方向に、図２６では右方に延びるように圧電層１６０の表面に形成されている。上部電極端子１６８及び下部電極端子１７０は、それぞれ補助電極１７２及び下部電極１６６の上面に形成されている。下部電極端子１７０は下部電極１６６と電気的に接触し、上部電極端子１６８は補助電極１７２を介して上部電極１６４と電気的に接触して、圧電素子とアクチュエータ１０６の外部との間の信号の受け渡しをする。上部電極端子１６８及び下部電極端子１７０は、電極と圧電層とを合わせた圧電素子の高さ以上の高さを有する。
【０１５５】
図２７は、図２４に示したアクチュエータ１０６の製造方法を示す。まず、グリーンシート９４０にプレスあるいはレーザー加工等を用いて貫通孔９４０ａを穿孔する。グリーンシート９４０は焼成後に基板１７８となる。グリーンシート９４０はセラミック等の材料で形成される。次に、グリーンシート９４０の表面にグリーンシート９４１を積層する。グリーンシート９４１は、焼成後に振動板１７６となる。グリーンシート９４１は、酸化ジルコニア等の材料で形成される。次に、グリーンシート９４１の表面に導電層９４２、圧電層１６０、導電層９４４を圧膜印刷等の方法で順次形成する。導電層９４２は、後に下部電極１６６となり、導電層９４４は、後に上部電極１６４となる。次に、形成されたグリーンシート９４０、グリーンシート９４１、導電層９４２、圧電層１６０、及び導電層９４４を乾燥して焼成する。スペーサ部材９４７、９４８は、上部電極端子１６８と下部電極端子１７０の高さを底上げして圧電素子より高くする。スペーサ部材９４７、９４８は、グリーンシート９４０、９４１と同材料を印刷、あるいはグリーンシートを積層して形成する。このスペーサ部材９４７，９４８により貴金属である上部電極端子１６８及び下部電極端子１７０の材料が少なくて済む上に、上部電極端子１６８及び下部電極端子１７０の厚みを薄くできるので、上部電極端子１６８及び下部電極端子１７０を精度良く印刷でき、さらに安定した高さとすることができる。
【０１５６】
導電層９４２の形成時に導電層９４４との接続部９４４’及びスペーサ部材９４７及び９４８を同時に形成すると、上部電極端子１６８及び下部電極端子１７０を容易に形成したり、強固に固定することができる。最後に、導電層９４２及び導電層９４４の端部領域に、上部電極端子１６８及び下部電極端子１７０を形成する。上部電極端子１６８及び下部電極端子１７０を形成する際、上部電極端子１６８及び下部電極端子１７０が、圧電層１６０に電気的に接続されるように形成する。
【０１５７】
図２８は、本発明が適用されるインクカートリッジのさらに他の実施形態を示す。図２８（Ａ）は、本実施形態によるインクカートリッジの底部の断面図である。本実施形態のインクカートリッジは、インクを収容する容器１の底面１ａに貫通孔１ｃを有する。貫通孔１ｃの底部はアクチュエータ６５０によって塞がれ、インク溜部を形成する。
【０１５８】
図２８（Ｂ）は、図２８（Ａ）に示したアクチュエータ６５０及び貫通孔１ｃの詳細な断面を示す。図２８（Ｃ）は、図２８（Ｂ）に示したアクチュエータ６５０及び貫通孔１ｃの平面を示す。アクチュエータ６５０は振動板７２および振動板７２に固定された圧電素子７３とを有する。振動板７２及び基板７１を介して圧電素子７３が貫通孔１ｃに対向するように、アクチュエータ６５０は、容器１の底面に固定される。振動板７２は、弾性変形可能で耐インク性を備える。
【０１５９】
容器１のインク量に依存して、圧電素子７３及び振動板７２の残留振動によって発生する逆起電力の振幅及び周波数が変化する。アクチュエータ６５０に対向する位置に貫通孔１ｃが形成されていて、最小限の一定量のインクが貫通孔１ｃに確保される。したがって、貫通孔１ｃに確保されるインク量により決まるアクチュエータ６５０の振動の特性を予め測定しておくことにより、容器１のインクエンドを確実に検出することができる。
【０１６０】
図２９は貫通孔１ｃの他の実施形態を示す。図２９（Ａ）、（Ｂ）、及び（Ｃ）のそれぞれにおいて、左側の図は、貫通孔１ｃにインクＫが無い状態を示し、右側の図は、貫通孔１ｃにインクＫが残った状態を示す。図２８の実施形態においては、貫通孔１ｃの側面は垂直な壁として形成されている。図２９（Ａ）においては、貫通孔１ｃは、側面１ｄが上下方向に斜めであり外側に拡大して開いている。図２９（Ｂ）においては、段差部１ｅ及び１ｆが、貫通孔１ｃの側面に形成されている。上方にある段差部１ｆが、下方にある段差部１ｅより広くなっている。図２９（Ｃ）においては、貫通孔１ｃは、インクＫを排出しやすい方向、すなわちインク供給口２の方向へ延びる溝１ｇを有する。
【０１６１】
図２９(Ａ)〜（Ｃ）に示した貫通孔１ｃの形状によれば、インク溜部のインクＫの量を少なくできる。従って、図２０および図２１で説明したＭ’ｃａｖをＭ’ｍａｘと比較して小さくすることができるので、インクエンド時におけるアクチュエータ６５０の振動特性を、容器１に印刷可能な量のインクＫが残存している場合と大きく異ならせることができるので、インクエンドをより確実に検出することができる。
【０１６２】
図３０はアクチュエータの他の実施形態を示す斜視図である。アクチュエータ６６０は、アクチュエータ６６０を構成する基板または取付プレート７８の貫通孔１ｃよりも外側にパッキン７６を有する。アクチュエータ６６０の外周にはカシメ孔７７が形成されている。アクチュエータ６６０は、カシメ孔７７を介してカシメにより容器１に固定される。
【０１６３】
図３１（Ａ）、（Ｂ）は、アクチュエータの更に他の実施形態を示す斜視図である。本実施形態においては、アクチュエータ６７０は、凹部形成基板８０および圧電素子８２を備える。凹部形成基板８０の一方の面には凹部８１がエッチング等の手法により形成され、他方の面には圧電素子８２が取り付けられる。凹部形成基板８０のうち、凹部８１の底部が振動領域として作用する。従って、アクチュエータ６７０の振動領域は凹部８１の周縁によって規定される。また、アクチュエータ６７０は、図２０の実施例によるアクチュエータ１０６のうち、基板１７８および振動板１７６が一体として形成された構造と類似する。従って、インクカートリッジを製造する際に製造工程を短縮することができ、コストを低減させる。アクチュエータ６７０は、容器１に設けられた貫通孔１ｃに埋め込み可能なサイズである。それによって、凹部８１がキャビティとしても作用することができる。尚、図２０の実施例によるアクチュエータ１０６を、図３１の実施例によるアクチュエータ６７０と同様に貫通孔１ｃに埋め込み可能なように形成してもよい。
【０１６４】
図３２は、アクチュエータ１０６を取り付けモジュール体１００として一体形成した構成を示す斜視図である。モジュール体１００はインクカートリッジの容器１の所定個所に装着される。モジュール体１００は、インク液中の少なくとも音響インピーダンスの変化を検出することにより、容器1内の液体の消費状態を検知するように構成されている。本実施形態のモジュール体１００は、容器１にアクチュエータ１０６を取り付けるための液体容器取付部１０１を有する。液体容器取付部１０１は、平面がほぼ矩形の基台１０２上に駆動信号により発振するアクチュエータ１０６を収容した円柱部１１６を載せた構造になっている。モジュール体１００が、インクカートリッジに装着されたときに、モジュール体１００のアクチュエータ１０６が外部から接触できないように構成されているので、アクチュエータ１０６を外部の接触から保護することができる。なお、円柱部１１６の先端側エッジは丸みが付けられていて、インクカートリッジに形成された孔へ装着する際に嵌めやすくなっている。
【０１６５】
図３３は、図３２に示したモジュール体１００の構成を示す分解図である。モジュール体１００は、樹脂からなる液体容器取付部１０１と、プレート１１０および凹部１１３を有する圧電装置装着部１０５とを含む。さらに、モジュール体１００は、リードワイヤ１０４ａ及び１０４ｂ、アクチュエータ１０６、およびフィルム１０８を有する。好ましくは、プレート１１０は、ステンレス又はステンレス合金等の錆びにくい材料から形成される。液体容器取付部１０１に含まれる円柱部１１６および基台１０２は、リードワイヤ１０４ａ及び１０４ｂを収容できるよう中心部に開口部１１４が形成され、アクチュエータ１０６、フィルム１０８、及びプレート１１０を収容できるように凹部１１３が形成される。アクチュエータ１０６はプレート１１０にフィルム１０８を介して接合され、プレート１１０およびアクチュエータ１０６は液体容器取付部１０１に固定される。従って、リードワイヤ１０４ａ及び１０４ｂ、アクチュエータ１０６、フィルム１０８およびプレート１１０は、液体容器取付部１０１に一体として取り付けられる。リードワイヤ１０４ａ及び１０４ｂは、それぞれアクチュエータ１０６の上部電極及び下部電極と結合して圧電層に駆動信号を伝達し、一方、アクチュエータ１０６が検出した共振周波数の信号を記録装置等へ伝達する。アクチュエータ１０６は、リードワイヤ１０４ａ及び１０４ｂから伝達された駆動信号に基づいて一時的に発振する。アクチュエータ１０６は発振後に残留振動し、その振動によって逆起電力を発生させる。このとき、逆起電力波形の振動周期を検出することによって、液体容器内の液体の消費状態に対応した共振周波数を検出することができる。フィルム１０８は、アクチュエータ１０６とプレート１１０とを接着してアクチュエータを液密にする。フィルム１０８は、ポリオレフィン等によって形成し、熱融着で接着することが好ましい。
【０１６６】
プレート１１０は円形状であり、基台１０２の開口部１１４は円筒状に形成されている。アクチュエータ１０６及びフィルム１０８は矩形状に形成されている。リードワイヤ１０４、アクチュエータ１０６、フィルム１０８、及びプレート１１０は、基台１０２に対して着脱可能としてもよい。基台１０２、リードワイヤ１０４、アクチュエータ１０６、フィルム１０８、及びプレート１１０は、モジュール体１００の中心軸に対して対称に配置されている。更に、基台１０２、アクチュエータ１０６、フィルム１０８、及びプレート１１０の中心は、モジュール体１００のほぼ中心軸上に配置されている。
【０１６７】
基台１０２の開口部１１４の面積は、アクチュエータ１０６の振動領域の面積よりも大きく形成されている。プレート１１０の中心でアクチュエータ１０６の振動部に直面する位置には、貫通孔１１２が形成されている。図２０および図２１に示したようにアクチュエータ１０６にはキャビティ１６２が形成され、貫通孔１１２とキャビティ１６２は、共にインク溜部を形成する。プレート１１０の厚さは、残留インクの影響を少なくするために貫通孔１１２の径に比べて小さいことが好ましい。例えば貫通孔１１２の深さはその径の３分の１以下の大きさであることが好ましい。貫通孔１１２は、モジュール体１００の中心軸に対して対称なほぼ真円の形状である。また貫通孔１１２の面積は、アクチュエータ１０６のキャビティ１６２の開口面積よりも大きい。貫通孔１１２の断面の周縁はテ-パ形状であっても良いしステップ形状でもよい。モジュール体１００は、貫通孔１１２が容器１の内側へ向くように容器１の側部、上部、又は底部に装着される。インクが消費されアクチュエータ１０６周辺のインクがなくなると、アクチュエータ１０６の共振周波数が大きく変化するので、インクの水位変化を検出することができる。
【０１６８】
図３４は、モジュール体の他の実施形態を示す斜視図である。本実施形態のモジュール体４００は、液体容器取付部４０１に圧電装置装着部４０５が形成されている。液体容器取付部４０１は、平面がほぼ角丸の正方形上の基台４０２上に円柱状の円柱部４０３が形成されている。更に、圧電装置装着部４０５は、円柱部４０３上に立てられた板状要素４０６および凹部４１３を含む。板状要素４０６の側面に設けられた凹部４１３には、アクチュエータ１０６が配置される。なお、板状要素４０６の先端は所定角度に面取りされていて、インクカートリッジに形成された孔へ装着する際に嵌めやすくなっている。
【０１６９】
図３５は、図３４に示したモジュール体４００の構成を示す分解斜視図である。図３２に示したモジュール体１００と同様に、モジュール体４００は、液体容器取付部４０１および圧電装置装着部４０５を含む。液体容器取付部４０１は基台４０２および円柱部４０３を有し、圧電装置装着部４０５は板状要素４０６および凹部４１３を有する。アクチュエータ１０６は、プレート４１０に接合されて凹部４１３に固定される。モジュール体４００は、リードワイヤ４０４ａ及び４０４ｂ、アクチュエータ１０６、及びフィルム４０８をさらに有する。
【０１７０】
本実施形態によれば、プレート４１０は矩形状であり、板状要素４０６に設けられた開口部４１４は矩形状に形成されている。リードワイヤ４０４ａ及び４０４ｂ、アクチュエータ１０６、フィルム４０８、及びプレート４１０は基台４０２に対して着脱可能として構成しても良い。アクチュエータ１０６、フィルム４０８、及びプレート４１０は、開口部４１４の中心を通り、開口部４１４の平面に対して鉛直方向に延びる中心軸に対して対称に配置されている。更に、アクチュエータ４０６、フィルム４０８、及びプレート４１０の中心は、開口部４１４のほぼ中心軸上に配置されている。
【０１７１】
プレート４１０の中心に設けられた貫通孔４１２の面積は、アクチュエータ１０６のキャビティ１６２の開口の面積よりも大きく形成されている。アクチュエータ１０６のキャビティ１６２と貫通孔４１２とは、共にインク溜部を形成する。プレート４１０の厚さは貫通孔４１２の径に比べて小さく、例えば貫通孔４１２の径の３分の１以下の大きさに設定することが好ましい。貫通孔４１２は、モジュール体４００の中心軸に対して対称なほぼ真円の形状である。貫通孔４１２の断面の周縁はテ-パ形状であっても良いしステップ形状でもよい。モジュール体４００は、貫通孔４１２が容器１の内部に配置されるように容器１の底部に装着することができる。アクチュエータ１０６が垂直方向に延びるように容器１内に配置されるので、基台４０２の高さを変えてアクチュエータ１０６が容器１内に配置される高さを変えることによりインクエンドの時点の設定を容易に変えることができる。
【０１７２】
図３６は、モジュール体の更に他の実施形態を示す。図３２に示したモジュール体１００と同様に、図３６のモジュール体５００は、基台５０２および円柱部５０３を有する液体容器取付部５０１を含む。また、モジュール体５００は、リードワイヤ５０４ａ及び５０４ｂ、アクチュエータ１０６、フィルム５０８、及びプレート５１０をさらに有する。液体容器取付部５０１に含まれる基台５０２は、リードワイヤ５０４ａ及び５０４ｂを収容できるよう中心部に開口部５１４が形成され、アクチュエータ１０６、フィルム５０８、及びプレート５１０を収容できるように凹部５１３が形成される。アクチュエータ１０６はプレート５１０を介して圧電装置装着部５０５に固定される。従って、リードワイヤ５０４ａ及び５０４ｂ、アクチュエータ１０６、フィルム５０８およびプレート５１０は、液体容器取付部５０１に一体として取り付けられる。本実施形態のモジュール体５００は、平面がほぼ角丸の正方形上の基台上に上面が上下方向に斜めな円柱部５０３が形成されている。円柱部５０３の上面の上下方向に斜めに設けられた凹部５１３上にアクチュエータ１０６が配置されている。
【０１７３】
モジュール体５００の先端は傾斜しており、その傾斜面にアクチュエータ１０６が装着されている。そのため、モジュール体５００が容器１の底部又は側部に装着されると、アクチュエータ１０６が容器１の上下方向に対して傾斜する。モジュール体５００の先端の傾斜角度は、検出性能を鑑みてほぼ３０°から６０°の間とすることが望ましい。
【０１７４】
モジュール体５００は、アクチュエータ１０６が容器１内に配置されるように容器１の底部又は側部に装着される。モジュール体５００が容器１の側部に装着される場合には、アクチュエータ１０６が、傾斜しつつ、容器１の上側、下側、又は横側を向くように容器１に取り付けられる。一方、モジュール体５００が、容器１の底部に装着される場合には、アクチュエータ１０６が、傾斜しつつ、容器１のインク供給口側を向くように容器１に取り付けられることが好ましい。
【０１７５】
図３７は、図３２に示したモジュール体１００を容器１に装着したときのインク容器の底部近傍の断面図である。モジュール体１００は、容器１の側壁を貫通するように装着されている。容器１の側壁とモジュール体１００との接合面には、Ｏリング３６５が設けられ、モジュール体１００と容器１との液密を保っている。Ｏリングでシールが出来るようにモジュール体１００は図３２で説明したような円柱部を備えることが好ましい。モジュール体１００の先端が容器１の内部に挿入されることで、プレート１１０の貫通孔１１２を介して容器１内のインクがアクチュエータ１０６と接触する。アクチュエータ１０６の振動部の周囲が液体か気体かによってアクチュエータ１０６の残留振動の共振周波数が異なるので、モジュール体１００を用いてインクの消費状態を検出することができる。また、モジュール体１００に限らず、図３４に示したモジュール体４００、図３６に示したモジュール体５００、又は図３８に示したモジュール体７００Ａ及び７００Ｂ、及びモールド構造体６００を容器１に装着してインクの有無を検出してもよい。
【０１７６】
図３８（Ａ）はモジュール体７００Ｂを容器１に装着したときのインク容器の断面図を示す。本実施例では取付構造体の１つとしてモジュール体７００Ｂを使用する。モジュール体７００Ｂは、液体容器取付部３６０が容器１の内部に突出するようにして容器１に装着されている。取付プレート３５０には貫通孔３７０が形成され、貫通孔３７０とアクチュエータ１０６の振動部が面している。更に、モジュール体７００Ｂの底壁には孔３８２が形成され、圧電装置装着部３６３が形成される。アクチュエータ１０６が孔３８２の一方を塞ぐようにして配備される。したがって、インクは、圧電装置装着部３６３の孔３８２及び取付プレート３５０の貫通孔３７０を介して振動板１７６と接触する。圧電装置装着部３６３の孔３８２及び取付プレート３５０の貫通孔３７０は、共にインク溜部を形成する。圧電装置装着部３６３とアクチュエータ１０６とは、取付プレート３５０及びフィルム部材によって固定されている。液体容器取付部３６０と容器１との接続部にはシーリング構造３７２が設けられている。シーリング構造３７２は合成樹脂等の可塑性の材料により形成されてもよいし、Ｏリングにより形成されてもよい。図３８（Ａ）のモジュール体７００Ｂと容器１とは別体であるが、図３８（Ｂ）ようにモジュール体７００Ｂの圧電装置装着部を容器１の一部で構成してもよい。
【０１７７】
図３８（Ａ）のモジュール体７００Ｂは、図３２から図３６に示したリードワイヤのモジュール体への埋め込みが不要となる。そのため成形工程が簡素化される。更に、モジュール体７００Ｂの交換が可能となりリサイクルが可能となる。
【０１７８】
インクカートリッジが揺れる際にインクが容器１の上面あるいは側面に付着し、容器１の上面あるいは側面から垂れてきたインクがアクチュエータ１０６に接触することでアクチュエータ１０６が誤作動する可能性がある。しかし、モジュール体７００Ｂは液体容器取付部３６０が容器１の内部に突出しているので、容器１の上面や側面から垂れてきたインクによりアクチュエータ１０６が誤作動しない。
【０１７９】
また、図３８（Ａ）の実施例では、振動板１７６と取付プレート３５０の一部のみが、容器１内のインクと接触するように容器１に装着される。図３８（Ａ）の実施例では、図３２から図３６に示したリードワイヤ１０４ａ、１０４ｂ、４０４ａ、４０４ｂ、５０４ａ、及び５０４ｂの電極のモジュール体への埋め込みが不要となる。そのため成形工程が簡素化される。更に、アクチュエータ１０６の交換が可能となりリサイクルが可能となる。
【０１８０】
図３８（Ｂ）は、アクチュエータ１０６を容器１に装着したときの実施例としてインク容器の断面図を示す。図３８（Ｂ）の実施例によるインクカートリッジでは、保護部材３６１はアクチュエータ１０６とは別体として容器１に取り付けられている。従って、保護部材３６１とアクチュエータ１０６とはモジュールとして一体となっていないが、一方で、保護部材３６１はアクチュエータ１０６にユーザーの手が触れないように保護することができる。アクチュエータ１０６の前面に設けられる孔３８０は、容器１の側壁に配設されている。アクチュエータ１０６は、圧電層１６０、上部電極１６４、下部電極１６６、振動板１７６及び取付プレート３５０を含む。取付プレート３５０の上面に振動板１７６が形成され、振動板１７６の上面に下部電極１６６が形成されている。下部電極１６６の上面には圧電層１６０が形成され、圧電層１６０の上面に上部電極１６４が形成されている。したがって、圧電層１６０の主要部は、上部電極１６４の主要部及び下部電極１６６の主要部によって上下から挟まれるように形成されている。圧電層１６０、上部電極１６４、及び下部電極１６６のそれぞれの主要部である円形部分は、圧電素子を形成する。圧電素子は振動板１７６上に形成される。圧電素子及び振動板１７６の振動領域はアクチュエータが実際に振動する振動部である。取付プレート３５０には貫通孔３７０が設けられている。更に、容器１の側壁には孔３８０が形成されている。したがって、インクは、容器１の孔３８０及び取付プレート３５０の貫通孔３７０を介して振動板１７６と接触する。容器１の孔３８０及び取付プレート３５０の貫通孔３７０は、共にインク溜部を形成する。また、図３８（Ｂ）の実施例では、アクチュエータ１０６は保護部材３６１により保護されているのでアクチュエータ１０６を外部との接触から保護できる。
【０１８１】
尚、図３８（Ａ）および（Ｂ）の実施例における取付プレート３５０に代えて、図２０の基板１７８を使用してもよい。
【０１８２】
図３８（Ｃ）はアクチュエータ１０６を含むモールド構造体６００を備える実施形態を示す。本実施例では、取付構造体の１つとしてモールド構造体６００を使用する。モールド構造体６００はアクチュエータ１０６とモールド部３６４とを有する。アクチュエータ１０６とモールド部３６４とは一体に成形されている。モールド部３６４はシリコン樹脂等の可塑性の材料によって成形される。モールド部３６４は内部にリードワイヤ３６２を有する。モールド部３６４はアクチュエータ１０６から延びる２本の足を有するように形成されている。モールド部３６４はモールド部３６４と容器１とを液密に固定するために、モールド部３６４の２本の足の端が半球状に形成される。モールド部３６４はアクチュエータ１０６が容器１の内部に突出するよう容器１に装着され、アクチュエータ１０６の振動部は容器１内のインクと接触する。モールド部３６４によって、アクチュエータ１０６の上部電極１６４、圧電層１６０、及び下部電極１６６はインクから保護されている。
【０１８３】
図３８（Ｃ）のモールド構造体６００は、モールド部３６４と容器１との間にシーリング構造３７２が必要ないので、インクが容器１から漏れにくい。また、容器１の外部からモールド構造体６００が突出しない形態であるので、アクチュエータ１０６を外部との接触から保護することができる。インクカートリッジが揺れる際に、インクが容器１の上面あるいは側面に付き、容器１の上面あるいは側面から垂れてきたインクが、アクチュエータ１０６に接触することで、アクチュエータ１０６が、誤作動する可能性がある。モールド構造体６００は、モールド部３６４が、容器１の内部に突出しているので、容器１の上面や側面から垂れてきたインクにより、アクチュエータ１０６が誤作動しない。
【０１８４】
図３９は、図２０に示したアクチュエータ１０６を用いたインクカートリッジ及びインクジェット記録装置の実施形態を示す。複数のインクカートリッジ１８０は、それぞれのインクカートリッジ１８０に対応した複数のインク導入部１８２及びホルダー１８４を有するインクジェット記録装置に装着される。複数のインクカートリッジ１８０は、それぞれ異なった種類、例えば色のインクを収容する。複数のインクカートリッジ１８０のそれぞれの底面には、少なくとも音響インピーダンスを検出する手段であるアクチュエータ１０６が装着されている。アクチュエータ１０６をインクカートリッジ１８０に装着することによって、インクカートリッジ１８０内のインク残量を検出することができる。
【０１８５】
図４０は、インクジェット記録装置のヘッド部周辺の詳細を示す。インクジェット記録装置は、インク導入部１８２、ホルダー１８４、ヘッドプレート１８６、及びノズルプレート１８８を有する。インクを噴射するノズル１９０がノズルプレート１８８に複数形成されている。インク導入部１８２は空気供給口１８１とインク導入口１８３とを有する。空気供給口１８１はインクカートリッジ１８０に空気を供給する。インク導入口１８３はインクカートリッジ１８０からインクを導入する。インクカートリッジ１８０は空気導入口１８５とインク供給口１８７とを有する。空気導入口１８５はインク導入部１８２の空気供給口１８１から空気を導入する。インク供給口１８７はインク導入部１８２のインク導入口１８３にインクを供給する。インクカートリッジ１８０がインク導入部１８２から空気を導入することによって、インクカートリッジ１８０からインク導入部１８２へのインクの供給を促す。ホルダー１８４は、インクカートリッジ１８０からインク導入部１８２を介して供給されたインクをヘッドプレート１８６に連通する。
【０１８６】
図４１は、図４０に示したインクカートリッジ１８０の他の実施形態を示す。図４１（Ａ）のインクカートリッジ１８０Ａは、上下方向に斜めに形成された底面１９４ａにアクチュエータ１０６が装着されている。インクカートリッジ１８０のインク容器１９４の内部には、インク容器１９４の内部底面から所定の高さの、アクチュエータ１０６と直面する位置に防波壁１９２が設けられている。アクチュエータ１０６が、インク容器１９４の上下方向に対し斜めに装着されているので、インクの掃けが良好になる。
【０１８７】
アクチュエータ１０６と防波壁１９２との間には、インクで満たされた間隙が形成される。また、防波壁１９２とアクチュエータ１０６との間隔は、毛細管力によりインクが保持されない程度に空けられている。インク容器１９４が横揺れしたときに、横揺れによってインク容器１９４内部にインクの波が発生し、その衝撃によって、気体や気泡がアクチュエータ１０６によって検出されてアクチュエータ１０６が誤作動する可能性がある。防波壁１９２を設けることによって、アクチュエータ１０６付近のインクの波を防ぎ、アクチュエータ１０６の誤作動を防ぐことができる。
【０１８８】
図４１（Ｂ）のインクカートリッジ１８０Ｂのアクチュエータ１０６は、インク容器１９４の供給口の側壁上に装着されている。インク供給口１８７の近傍であれば、アクチュエータ１０６は、インク容器１９４の側壁又は底面に装着されてもよい。また、アクチュエータ１０６はインク容器１９４の幅方向の中心に装着されることが好ましい。インクは、インク供給口１８７を通過して外部に供給されるので、アクチュエータ１０６をインク供給口１８７の近傍に設けることにより、インクニアエンド時点までインクとアクチュエータ１０６とが確実に接触する。したがって、アクチュエータ１０６はインクニアエンドの時点を確実に検出することができる。
【０１８９】
更に、アクチュエータ１０６をインク供給口１８７の近傍に設けることで、インク容器をキャリッジ上のカートリッジホルダに装着する際に、インク容器上のアクチュエータ１０６とキャリッジ上の接点との位置決めが確実となる。その理由は、インク容器とキャリッジとの連結において最も重要なのは、インク供給口と供給針との確実な結合である。少しでもずれがあると供給針の先端を痛めてしまったりあるいはＯリングなどのシーリング構造にダメージを与えてしまいインクが漏れ出してしまうからである。このような問題点を防ぐために、通常インクジェットプリンタはインク容器をキャリッジにマウントする時に正確な位置合わせができるような特別な構造を有している。よって供給口近傍にアクチュエータを配置させることにより、アクチュエータの位置合わせも同時に確実なものとなるのである。さらに、アクチュエータ１０６をインク容器１９４の幅方向の中心に装着することで、より確実に位置合わせすることができる。インク容器が、ホルダへの装着時に幅方向中心線を中心として軸揺動した場合に、もっともその揺れが少ないからである。
【０１９０】
図４２はインクカートリッジ１８０の更に他の実施形態を示す。図４２（Ａ）はインクカートリッジ１８０Ｃの断面図、図４２（Ｂ）は図４２（Ａ）に示したインクカートリッジ１８０Ｃの側壁１９４ｂを拡大した断面図、及び図４２（Ｃ）はその正面からの透視図である。インクカートリッジ１８０Ｃは、半導体記憶手段７とアクチュエータ１０６とが同一の回路基板６１０上に形成されている。図４２（Ｂ）、（Ｃ）に示すように、半導体記憶手段７は回路基板６１０の上方に形成され、アクチュエータ１０６は同一の回路基板６１０において半導体記憶手段７の下方に形成されている。アクチュエータ１０６の周囲を囲むように異型Ｏリング６１４が、側壁１９４ｂに装着される。側壁１９４ｂには、回路基板６１０をインク容器１９４に接合するためのカシメ部６１６が複数形成されている。カシメ部６１６によって回路基板６１０をインク容器１９４に接合し、異型Ｏリング６１４を回路基板６１０に押しつけることで、アクチュエータ１０６の振動領域がインクと接触することをできるようにしつつ、インクカートリッジの外部と内部とを液密に保つ。
【０１９１】
半導体記憶手段７及び半導体記憶手段７付近には端子６１２が形成されている。端子６１２は半導体記憶手段７とインクジェット記憶装置等の外部との間の信号の受け渡しをする。半導体記憶手段７は、例えばＥＥＰＲＯＭなどの書き換え可能な半導体メモリによって構成されてもよい。半導体記憶手段７とアクチュエータ１０６とが同一の回路基板６１０上に形成さているので、アクチュエータ１０６及び半導体記憶手段７をインクカートリッジ１８０Ｃに取付ける際に１回の取付け工程で済む。また、インクカートリッジ１８０Ｃの製造時及びリサイクル時の作業工程が簡素化される。更に、部品の点数が削減されるので、インクカートリッジ１８０Ｃの製造コストが低減できる。
【０１９２】
アクチュエータ１０６は、インク容器１９４内のインクの消費状態を検知する。半導体記憶手段７はアクチュエータ１０６が検出したインク残量などインクの情報を格納する。すなわち、半導体記憶手段７は検出する際に用いられるインク及びインクカートリッジの特性等の特性パラメータに関する情報を格納する。半導体記憶手段７は、予めインク容器１９４内のインクがフルのとき、すなわちインクがインク容器１９４内に満たされたとき、又はエンドのとき、すなわちインク容器１９４内のインクが消費されたときの共振周波数を特性パラメータの一つとして格納する。インク容器１９４内のインクがフル又はエンド状態の共振周波数は、インク容器が初めてインクジェット記録装置に装着されたときに格納されてもよい。また、インク容器１９４内のインクがフル又はエンド状態の共振周波数は、インク容器１９４の製造中に格納されてもよい。半導体記憶手段７に予めインク容器１９４内のインクがフル又はエンドのときの共振周波数を格納し、インクジェット記録装置側で共振周波数のデータを読出すことによりインク残量を検出する際のばらつきを補正できるので、インク残量が基準値まで減少したことを正確に検出することができる。
【０１９３】
図４３は、インクカートリッジ１８０の更に他の実施形態を示す。図４３（Ａ）に示すインクカートリッジ１８０Ｄは、インク容器１９４の側壁１９４ｂに複数のアクチュエータ１０６を装着する。図２４に示した、一体成形された複数のアクチュエータ１０６を、これら複数のアクチュエータ１０６として用いることが好ましい。複数のアクチュエータ１０６は、上下方向に間隔をおいて側壁１９４ｂに配置されている。複数のアクチュエータ１０６を上下方向に間隔をおいて側壁１９４ｂに配置することによって、インク残量を段階的に検出することができる。
【０１９４】
図４３（Ｂ）に示すインクカートリッジ１８０Ｅは、インク容器１９４の側壁１９４ｂに上下方向に長いアクチュエータ６０６を装着する。上下方向に長いアクチュエータ６０６によって、インク容器１９４内のインク残量の変化を連続的に検出することができる。アクチュエータ６０６の長さは、側壁１９４ｂに高さの半分以上の長さを有することが望ましく、図４３（Ｂ）においては、アクチュエータ６０６は側壁１９４ｂのほぼ上端からほぼ下端までの長さを有する。
【０１９５】
図４３（Ｃ）に示すインクカートリッジ１８０Ｆは、図４３（Ａ）に示したインクカートリッジ１８０Ｄと同様に、インク容器１９４の側壁１９４ｂに複数のアクチュエータ１０６を装着し、複数のアクチュエータ１０６の直面に所定の間隔をおいて上下方向に長い防波壁１９２を備える。図２４に示した、一体成形された複数のアクチュエータ１０６を、これら複数のアクチュエータ１０６として用いることが好ましい。アクチュエータ１０６と防波壁１９２との間には、インクで満たされた間隙が形成される。また、防波壁１９２とアクチュエータ１０６との間隔は、毛細管力によりインクが保持されない程度に空けられている。インク容器１９４が横揺れしたときに横揺れによってインク容器１９４内部にインクの波が発生し、その衝撃によって気体や気泡がアクチュエータ１０６によって検出されてしまい、アクチュエータ１０６が誤作動する可能性がある。本発明のように防波壁１９２を設けることによって、アクチュエータ１０６付近のインクの波立ちを防ぎ、アクチュエータ１０６の誤作動を防ぐことができる。また、防波壁１９２はインクが揺動することで発生した気泡がアクチュエータ１０６に侵入するのを防ぐ。
【０１９６】
図４４は、インクカートリッジ１８０の更に他の実施形態を示す。図４４（Ａ）のインクカートリッジ１８０Ｇは、インク容器１９４の上面１９４ｃから下方に延びる複数の隔壁２１２を有する。それぞれの隔壁２１２の下端とインク容器１９４の底面とは所定の間隔が空けられているので、インク容器１９４の底部は連通している。インクカートリッジ１８０Ｇは複数の隔壁２１２のそれぞれによって区画された複数の収容室２１３を有する。複数の収容室２１３の底部は互いに連通する。複数の収容室２１３のそれぞれにおいて、インク容器１９４の上面１９４ｃにはアクチュエータ１０６が装着されている。図２４に示した、一体成形されたアクチュエータ１０６を、これら複数のアクチュエータ１０６として用いることが好ましい。アクチュエータ１０６は、インク容器１９４の収容室２１３の上面１９４ｃのほぼ中央に配置される。収容室２１３の容量はインク供給口１８７側が最も大きく、インク供給口１８７からインク容器１９４の奥へ遠ざかるにつれて、収容室２１３の容量が徐々に小さくなっている。したがって、アクチュエータ１０６が配置される間隔はインク供給口１８７側が広く、インク供給口１８７からインク容器１９４の奥へと遠ざかるにつれ、狭くなっている。
【０１９７】
インクは、インク供給口１８７から排出され、空気が空気導入口１８５から入るので、インク供給口１８７側の収容室２１３からインクカートリッジ１８０Ｇの奥の方の収容室２１３へとインクが消費される。例えば、インク供給口１８７に最も近い収容室２１３のインクが消費されて、インク供給口１８７に最も近い収容室２１３のインクの水位が下がっている間、他の収容室２１３にはインクが満たされている。インク供給口１８７に最も近い収容室２１３のインクが消費され尽くすと、空気が、インク供給口１８７から数えて２番目の収容室２１３に侵入し、２番目の収容室２１３内のインクが消費され始めて、２番目の収容室２１３のインクの水位が下がり始める。この時点で、インク供給室１８７から数えて３番目以降の収容室２１３には、インクが満たされている。このように、インク供給口１８７に近い収容室２１３から遠い収容室２１３へと順番にインクが消費される。
【０１９８】
このように、アクチュエータ１０６がそれぞれの収容室２１３ごとにインク容器１９４の上面１９４ｃに間隔をおいて配置されているので、アクチュエータ１０６はインク量の減少を段階的に検出することができる。更に、収容室２１３の容量が、インク供給口１８７から収容室２１３の奥へと徐々に小さくなっているので、アクチュエータ１０６が、インク量の減少を検出する時間間隔が徐々に小さくなり、インクエンドに近づくほど頻度を高く検出することができる。
【０１９９】
図４４（Ｂ）のインクカートリッジ１８０Ｈは、インク容器１９４の上面１９４ｃから下方に延びる一つの隔壁２１２を有する。隔壁２１２の下端とインク容器１９４の底面とは所定の間隔が空けられているので、インク容器１９４の底部は連通している。インクカートリッジ１８０Ｈは隔壁２１２によって区画された２室の収容室２１３ａ及び２１３ｂを有する。収容室２１３ａ及び２１３ｂの底部は互いに連通する。インク供給口１８７側の収容室２１３ａの容量はインク供給口１８７から見て奥の方の収容室２１３ｂの容量より大きい。収容室２１３ｂの容量は、収容室２１３ａの容量の半分より小さいことが好ましい。
【０２００】
収容室２１３ｂの上面１９４ｃにアクチュエータ１０６が装着される。更に、収容室２１３ｂには、インクカートリッジ１８０Ｈの製造時に入る気泡を捕らえる溝であるバッファ２１４が形成される。図４４（Ｂ）において、バッファ２１４は、インク容器１９４の側壁１９４ｂから上方に延びる溝として形成される。バッファ２１４はインク収容室２１３ｂ内に侵入した気泡を捕らえるので、気泡によってアクチュエータ１０６がインクエンドと検出する誤作動を防止することができる。また、アクチュエータ１０６を収容室２１３ｂの上面１９４ｃに設けることにより、インクニアエンドが検出されてから完全にインクエンド状態になるまでのインク量に対して、ドットカウンタによって把握した収容室２１３ａでのインクの消費状態に対応した補正をかけることで、最後までインクを消費することができる。更に、収容室２１３ｂの容量を隔壁２１２の長さや間隔を変えたりすることなどによって調節することにより、インクニアエンド検出後の消費可能インク量を変えることができる。
【０２０１】
図４４（Ｃ）は、図４４（Ｂ）のインクカートリッジ１８０Ｉの収容室２１３ｂに多孔質部材２１６が充填されている。多孔質部材２１６は、収容室２１３ｂ内の上面から下面までの全空間を埋めるように設置される。多孔質部材２１６は、アクチュエータ１０６と接触する。インク容器が倒れたときや、キャリッジ上での往復運動中に空気がインク収容室２１３ｂ内に侵入してしまい、これがアクチュエータ１０６の誤作動を引き起こす可能性がある。しかし、多孔質部材２１６が備えられていれば、空気を捕らえてアクチュエータ１０６に空気が入るのを防ぐことができる。また、多孔質部材２１６はインクを保持するのでインク容器が揺れることにより、インクがアクチュエータ１０６にかかってアクチュエータ１０６がインク無しをインク有りと誤検出するのを防ぐことができる。多孔質部材２１６は最も容量が小さい収容室２１３に設置することが好ましい。また、アクチュエータ１０６を収容質２１３ｂの上面１９４ｃに設けることにより、インクニアエンドが検出されてから完全にインクエンド状態になるまでのインク量に補正をかけ、最後までインクを消費することができる。更に、収容室２１３ｂの容量を隔壁２１２の長さや間隔を変えたりすることなどによって調節することにより、インクニアエンド検出後の消費可能インク量を変えることができる。
【０２０２】
図４４（Ｄ）は、図４４（Ｃ）のインクカートリッジ１８０Ｉの多孔質部材２１６が孔径の異なる２種類の多孔質部材２１６Ａ及び２１６Ｂによって構成されているインクカートリッジ１８０Ｊを示す。多孔質部材２１６Ａは、多孔質部材２１６Ｂの上方に配置されている。上側の多孔質部材２１６Ａの孔径は、下側の多孔質部材２１６Ｂの孔径より大きい。もしくは、多孔質部材２１６Ａは、多孔質部材２１６Ｂよりも液体親和性が低い部材で形成される。孔径の小さい多孔質部材２１６Ｂの方が孔径の大きい多孔質部材２１６Ａより毛細管力は大きいので、収容室２１３ｂ内のインクが下側の多孔室部材２１６Ｂに集まり、保持される。したがって、一度空気がアクチュエータ１０６まで到達してインク無しを検出すると、インクが再度アクチュエータに到達してインク有りと検出することが無い。更に、アクチュエータ１０６から遠い側の多孔質部材２１６Ｂにインクが吸収されることで、アクチュエータ１０６近傍のインクの捌けが良くなり、インク有無を検出するときの音響インピーダンス変化の変化量が大きくなる。また、アクチュエータ１０６を収容質２１３ｂの上面１９４ｃに設けることにより、インクニアエンドが検出されてから完全にインクエンド状態になるまでのインク量に補正をかけ、最後までインクを消費することができる。更に、収容室２１３ｂの容量を隔壁２１２の長さや間隔を変えたりすることなどによって調節することにより、インクニアエンド検出後の消費可能インク量を変えることができる。
【０２０３】
図４５は、図４４（Ｃ）に示したインクカートリッジ１８０Ｉの他の実施形態であるインクカートリッジ１８０Ｋを示す断面図である。図４５に示すインクカートリッジ１８０の多孔質部材２１６は、多孔質部材２１６の下部の水平方向の断面積が、インク容器１９４の底面の方向にむけて徐々に小さくなるように圧縮され、孔径が小さくなるよう設計されている。図４５（Ａ）のインクカートリッジ１８０Ｋは、多孔質部材２１６の下の方の孔径が小さくなるように圧縮するために側壁にリブが設けられている。多孔質部材２１６下部の孔径は圧縮されることにより、小さくなっているので、インクは多孔質部材２１６下部へと集められ、保持される。アクチュエータ１０６から遠い側の多孔質部材２１６下部にインクが吸収されることで、アクチュエータ１０６近傍のインクの捌けが良くなり、インク有無を検出するときの音響インピーダンス変化の変化量が大きくなる。したがって、インクが揺れることによってインクカートリッジ１８０Ｋ上面に装着されたアクチュエータ１０６にインクがかかっていしまい、アクチュエータ１０６が、インク無しをインク有りと誤検出することを防止することができる。
【０２０４】
一方、図４５（Ｂ）及び図４５（Ｃ）のインクカートリッジ１８０Ｌは、多孔質部材２１６の下部の水平方向の断面積が、インク容器１９４の幅方向において、インク容器１９４の底面にむけて徐々に小さくなるよう圧縮するために、収容室の水平方向の断面積がインク容器１９４の底面の方向にむけて徐々に小さくなっている。多孔質部材２１６下部の孔径は圧縮されることにより、小さくなっているので、インクは多孔質部材２１６の下部へと集められ、保持される。アクチュエータ１０６から遠い側の多孔質部材２１６Ｂの下部にインクが吸収されることで、アクチュエータ１０６近傍のインクの捌けが良くなり、インク有無を検出するときの音響インピーダンス変化の変化量が大きくなる。したがって、インクが揺れることによって、インクカートリッジ１８０Ｌの上面に装着されたアクチュエータ１０６にインクがかかっていしまい、アクチュエータ１０６が、インク無しをインク有りと誤検出することを防止することができる。
【０２０５】
図４６は、アクチュエータ１０６を用いたインクカートリッジの更に他の実施形態を示す。図４６（Ａ）のインクカートリッジ２２０Ａは、インクカートリッジ２２０Ａの上面から下方へと延びるように設けられた第１の隔壁２２２を有する。第１の隔壁２２２の下端とインクカートリッジ２２０Ａの底面との間には所定の間隔が空けられているので、インクは、インクカートリッジ２２０Ａの底面を通じてインク供給口２３０へ流入できる。第１の隔壁２２２よりインク供給口２３０側には、インクカートリッジ２２０Ａの底面より上方に延びるように第２の隔壁２２４が、形成されている。第２の隔壁２２４の上端とインクカートリッジ２２０Ａ上面との間には所定の間隔が空けられているので、インクは、インクカートリッジ２２０Ａの上面を通じてインク供給口２３０へ流入できる。
【０２０６】
第１の隔壁２２２によって、インク供給口２３０から見て、第１の隔壁２２２の奥の方に第１の収容室２２５ａが形成される。一方、第２の隔壁２２４によって、インク供給口２３０から見て第２の隔壁２２４の手前側に第２の収容室２２５ｂが形成される。第１の収容室２２５ａの容量は、第２の収容室２２５ｂの容量より大きい。第１の隔壁２２２及び第２の隔壁２２４の間に、毛管現象を起こせるだけの間隔が空けられることにより、毛管路２２７が形成される。したがって、第１の収容室２２５ａのインクは、毛管路２２７の毛細管力により、毛管路２２７に集められる。そのため、気体や気泡が第２の収容室２２５ｂへ混入するのを防止することができる。また、第２の収容室２２５ｂ内のインクの水位は、安定的に徐々に下降できる。インク供給口２３０から見て、第１の収容室２２５ａは、第２の収容室２２５ｂより奥に形成されているので、第１の収容室２２５ａのインクが消費された後、第２の収容室２２５ｂのインクが消費される。
【０２０７】
インクカートリッジ２２０Ａのインク供給口２３０側の側壁、すなわち第２の収容室２２５ｂのインク供給口２３０側の側壁には、アクチュエータ１０６が装着されている。アクチュエータ１０６は、第２の収容室２２５ｂ内のインクの消費状態を検知する。アクチュエータ１０６を、第２の収容室２２５ｂの側壁に装着することによって、インクエンドにより近い時点でのインク残量を安定的に検出することができる。更に、アクチュエータ１０６を第２の収容室２２５ｂの側壁に装着する高さを変えることにより、どの時点でのインク残量をインクエンドにするかを、自由に設定することができる。毛管路２２７によって第１の収容室２２５ａから第２の収容室２２５ｂへインクが供給されることにより、アクチュエータ１０６は、インクカートリッジ２２０Ａの横揺れによるインクの横揺れの影響を受けないので、アクチュエータ１０６は、インク残量を確実に測定できる。更に、毛管路２２７が、インクを保持するので、インクが第２の収容室２２５ｂから第１の収容室２２５ａへ逆流するのを防ぐ。
【０２０８】
インクカートリッジ２２０Ａの上面には、逆止弁２２８が設けられている。逆止弁２２８によって、インクカートリッジ２２０Ａが横揺れしたときに、インクがインクカートリッジ２２０Ａ外部に漏れるのを防ぐことができる。更に、逆止弁２２８をインクカートリッジ２２０Ａの上面に設置することで、インクのインクカートリッジ２２０Ａからの蒸発を防ぐことができる。インクカートリッジ２２０Ａ内のインクが消費されて、インクカートリッジ２２０Ａ内の負圧が逆止弁２２８の圧力を越えると、逆止弁２２８が開いて、インクカートリッジ２２０Ａに空気を吸入し、その後閉じてインクカートリッジ２２０Ａ内の圧力を一定に保持する。
【０２０９】
図４６（Ｃ）及び（Ｄ）は、逆止弁２２８の詳細の断面を示す。図４６（Ｃ）の逆止弁２２８は、ゴムにより形成された羽根２３２ａを有する弁２３２を有する。インクカートリッジ２２０の外部との通気孔２３３が、羽根２３２ａに対向してインクカートリッジ２２０に設けられる。羽根２３２ａによって、通気孔２３３が、開閉される。逆止弁２２８は、インクカートリッジ２２０内のインクが減少し、インクカートリッジ２２０内の負圧が逆止弁２２８の圧力を越えると、羽根２３２ａが、インクカートリッジ２２０の内側に開き、外部の空気をインクカートリッジ２２０内に取り入れる。図４６（Ｄ）の逆止弁２２８は、ゴムにより形成された弁２３２とバネ２３５とを有する。逆止弁２２８は、インクカートリッジ２２０内の負圧が逆止弁２２８の圧力を越えると、弁２３２が、バネ２３５を押圧して開き、外部の空気をインクカートリッジ２２０内に吸入し、その後閉じてインクカートリッジ２２０内の負圧を一定に保持する。
【０２１０】
図４６（Ｂ）のインクカートリッジ２２０Ｂは、図４６（Ａ）のインクカートリッジ２２０Ａにおいて逆止弁２２８を設ける代わりに第１の収容室２２５ａに多孔質部材２４２を配置している。多孔質部材２４２は、インクカートリッジ２２０Ｂ内のインクを保持すると共に、インクカートリッジ２２０Ｂが横揺れしたときに、インクがインクカートリッジ２２０Ｂの外部へ漏れるのを防ぐ。
【０２１１】
以上、キャリッジに装着される、キャリッジと別体のインクカートリッジにおいて、インクカートリッジ又はキャリッジにアクチュエータ１０６を装着する場合について述べたが、キャリッジと一体化され、キャリッジと共に、インクジェット記録装置に装着されるインクタンクにアクチュエータ１０６を装着してもよい。更に、キャリッジと別体の、チューブ等を介して、キャリッジにインクを供給するオフキャリッジ方式のインクタンクにアクチュエータ１０６を装着してもよい。またさらに、記録ヘッドとインク容器とが一体となって交換可能に構成されたインクカートリッジに、本発明のアクチュエータを装着してもよい。
【０２１２】
「複数の液体センサを用いたインク検出技術」
以上、液体センサ（弾性波発生手段およびアクチュエータ）を利用してインク消費を検出する各種のインクカートリッジを説明した。これらの中には、例えば図１０に示されるように、複数の液体センサをインクカートリッジに設ける構成が示された。本実施の形態では、これら複数の液体センサを利用してインク消費をさらに適切に検出する。
【０２１３】
図４７は、本実施の形態にかかるインクジェット記録装置の制御システムを示している。インクカートリッジ８００の容器壁には、三つの液体センサ８０２、８０４、８０６が設置されている。各液体センサは圧電素子を有し、上述のアクチュエータまたは弾性波発生手段に相当する。三つの液体センサ８０２〜８０６は、インク消費による液面変化方向（典型的には液面低下方向であり、そして、本実施の形態では液面低下方向を主として想定する）に沿って異なる位置に設置されている。これらの液体センサは、記録装置制御部８１０の計測処理部８１２により制御される。記録装置制御部８１０は、さらに、提示処理部８１４、印刷動作制御部８１６、インク補充処理部８１８、カートリッジ交換処理部８２０および印刷データ記憶処理部８２２を有する。これらの構成については後述する。
【０２１４】
計測処理部８１２の制御のもとで、各液体センサ８０２〜８０６に駆動電圧が印加されると、液体センサが振動する。上述した一つの手法では、インク消費に伴う音響インピーダンスの変化が利用される。液体センサを駆動した後の残留振動が検出される。別の手法では、液体センサは、振動により弾性波を発生した後、弾性波に対する反射波に応じた信号を出力する。反射波が返ってくるまでの時間が検出されてもよい。圧電素子を利用するその他の手法が適用されてもよい。
【０２１５】
液面がセンサより高いか否かによって音響インピーダンスが大きく変化するので、液体センサの検出信号が異なる。計測処理部８１２は、検出信号に基づいて、インクの液面が各センサを通過したか否かを判定できる。検出処理は、予め定められたタイミングで定期的に行われる。
【０２１６】
ここで、液面がセンサより低い状態を「インク空状態」とし、液面がセンサより高い状態を「インク有り状態」とする。液面がセンサを通過すると、「インク有り状態」から「インク空状態」へ検出結果が変化する。本実施の形態では、液面通過の検知とは、この検出結果の変化を示す。
【０２１７】
本実施形態の特徴として、計測処理部８１２は、センサの検出位置を、インク消費の進行に応じて、インク液面の低下方向に沿って切り換える。カートリッジの装着直後、すなわちインクフル状態では、液体センサ８０２のみが使用される。インクが消費され、液面がセンサ８０２を通過すると、液体センサ８０２はインク空状態を検出する。これに応えて、計測処理部８１２は、インク検出位置を中段に切り換える。すなわち、液体センサ８０４のみを用いてインク消費が検出される。同様にして、液体センサ８０４がインク空状態を検出すると、検出位置が最下段（液体センサ８０６）へと切り換えられる。
【０２１８】
本実施の形態によれば、検出位置を順次下方に切り換えていくので、全ての液体センサが常に動作しなくてもよく、液体センサの動作が少なくなる。これにより、計測処理部８１２でのデータ処理量も減らすことができる。
【０２１９】
さらに、本実施の形態では、インク液面の変化に応じて検出頻度が増大される。検出位置を下側にシフトするときに、検出頻度を増大することが好ましい。すなわち、検出処理の間隔が短く変更される。これにより、以下に説明するように、全体としての検出回数を少なくできる。
【０２２０】
例えば、インクの液面が液体センサ８０２よりも高いときは、インクが十分に大量にあるので、液面のセンサ通過を早く発見する必要性は低い。そこで、液体センサ８０２がインク空状態を検出するまでは、検出頻度が比較的小さく設定される。一方、インクの液面が液体センサ８０４を通過した後は、次にインク液面の通過を検出するのは液体センサ８０６である。液体センサ８０６は一番下に位置し、インクニアエンド（インクの完全消費に近い状態）を検出する。液体センサ８０６は、液面の通過を早く検出することが好ましい。そこで、液体センサ８０６の検出頻度は、液体センサ８０２よりも大きく設定される。このような制御により、インク消費を早めに検出することが望まれるときの検出頻度を大きくするとともに、その他の状態での検出頻度を低くできる。必要な情報の入手を確保した上で、全体としての検出処理回数を少なくできる。
【０２２１】
本実施形態の利点は、液体センサがひとつの場合と比べると顕著である。仮に、インクニアエンドを検出する液体センサ８０６のみが設けられているとする。この場合、液体センサ８０６は液面の到来をいち早く検出するために、常に高い頻度で検出処理を繰り返さなければならない。これに対し、本実施形態によれば、インクの消費が進んでいないときは、液体センサ８０２または液体センサ８０４を用いて比較的低い頻度でインク消費を検出すればよい。したがって、液体センサの動作する回数を大幅に低減することができる。
【０２２２】
以上に説明したように、本実施の形態によれば、比較的少ない検出動作で効率よく正確にインクの消費状態を捕捉できる。計測処理部８１２による処理の負担が軽くなる。これは記録装置制御部８１０の他の構成にとっても有利である。例えば、大型の記録装置において長時間高速で印刷を続ける場合を考えると、印刷処理の途中で計測処理を行う回数を少なくできる。
【０２２３】
なお、本実施形態においては、検出位置を切り換えるたびに常に検出頻度を変える必要はない。例えば、図４７の液体センサ８０２および液体センサ８０４は同じ頻度でインク消費を検出してもよい。あるいは、液体センサ８０４と液体センサ８０６の検出頻度が同じでもよい。
【０２２４】
また、本実施の形態においては、液体センサの数が三つであった。しかしながら、液体センサの数は二つ以上であればいくつでもよい。また、液体センサの間隔は一定でなくてもよい。たとえば、液面が低くなるほど液体センサの間隔を狭くすることが好適である。こうした変形は、以下の他の実施形態においても同様に適用可能である。
【０２２５】
「インク消費状態に基づくインクジェット記録装置の制御」
図４７に戻り、記録装置制御部８１０は、さらに、提示処理部８１４、印刷動作制御部８１６、インク補充処理部８１８、カートリッジ交換処理部８２０および印刷データ記憶処理部８２２を有している。これらの構成は、計測処理部８１２により検出されたインク消費状態に基づいてインクジェット記録装置を制御する。本実施の形態では、複数の検出位置でインピーダンス変化を検出することにより、液面位置が段階的に検出される。センサがひとつの場合には得られない複数の液面位置がもとめられる。この液面位置情報を利用するので、記録装置の制御も好適に行える。なお、記録装置制御部８１０は、インクジェット記録装置の内部に設けられてもよく、あるいは外部に設けられてもよい。制御部８１０の一部または全部の機能が、記録装置に接続されたコンピュータ等の外部装置に与えられてもよい。
【０２２６】
提示処理部８１４は、液面通過を検知した液体センサに対応する情報を提示する。情報の提示には、ディスプレイ８３０およびスピーカ８３２が用いられる。ディスプレイ８３０は、例えば記録装置の表示パネルである。また、ディスプレイ８３０は、記録装置に接続されたコンピュータの画面でもよい。好ましくは、液面通過を検出した液体センサに応じて表示形態が変更される。
【０２２７】
図４８は、表示形態を異ならせる処理の例を示している。最も高い位置にある液体センサ８０２が液面通過を検出した時は、青色の長い棒図形が表示される。液体センサ８０２の検出前から、同様の図形が表示されていてもよい。次に、中段の液体センサ８０４が液面通過を検出したときは、中くらいの長さの棒図形であって黄色い棒図形が表示される。さらに、一番下の液体センサ８０６が液面通過を検知したときは、赤色の短い棒図形が表示される。また、表示は直接ＬＥＤ等を用いる形態でもよい。こうした表示形態の変更、詳細には色および図形の変更により、インクの消費状態をわかりやすくユーザに伝えることができる。
【０２２８】
また、提示処理部８１４は、スピーカ８３２を用いて情報を提示する。液体センサが液面通過を検出すると、報知音がスピーカ８３２から出力される。スピーカ８３２は、記録装置のスピーカでもよく、記録装置に接続されたコンピュータ等の外部装置のスピーカでもよい。好ましくは、ここでも液体センサに応じて報知音を異ならせる。また報知音として音声信号を用いることも好適である。音声合成処理によりインク消費状態を示す合成音声が生成される。このときは、メッセージの中身がインク量に応じて、すなわち液面通過を検知した液体センサに応じて変更される。
【０２２９】
記録装置制御部８１０の他の構成（８１６、８１８・・・）は、インクカートリッジの最も低い位置に取り付けられた液体センサ（図４７、８０６）が液面通過を検知したのに応答して、所定の低インク量対応処理を行う。低インク量対応処理は、インクが残り少なくなったことを考慮して、不適切な印刷等の記録装置の動作を禁止または抑制する処理である。
【０２３０】
印刷動作制御部８１６は、印刷装置８３４を制御して、低インク対応処理として、印刷動作を停止する。これにより、インクが無くなった後の印刷動作が回避される。
【０２３１】
印刷動作制御部８１６は、低インク対応処理として、印刷メンテナンス動作（クリーニング動作）を禁止してもよい。本実施の形態では、印刷メンテナンスの対象に印刷ヘッドが含まれる。この印刷ヘッドのメンテナンスの際に、比較的多くのインクがヘッドから吸引される。この形態によれば、残り少ないインクがメンテナンスのためにヘッドから吸引されるのを回避でき、これにより、メンテナンスのためにインクが不足するという事態も回避できる。
【０２３２】
また、印刷動作制御部８１６は、低インク量対応処理の他の例として、ある印刷処理を終了してから次の印刷処理に移るのを禁止してもよい。これにより、ひとつの印刷処理、たとえば一連の文章の印刷途中で印刷が停止するのを回避できる。
【０２３３】
インク補充処理部８１８は、低インク量対応処理として、インク補充装置８３６を制御してインクカートリッジにインクを自動的に補充する。これにより、印刷を継続することができる。
【０２３４】
カートリッジ交換処理部８２０は、低インク量対応処理として、カートリッジ交換装置８３８を制御してインクカートリッジを自動的に交換する。この対応処理によっても印刷動作を継続することができる。
【０２３５】
印刷データ記憶処理部８２２は、低インク量対応処理として、印刷完了前の印刷データを印刷データ記憶部８４０に格納する。これにより、印刷前の印刷データが失われるのを回避できる。
【０２３６】
これらの構成８１４〜８２２の全てが記録装置制御部８１０に設けられていなくてもよい。少なくともひとつの低インク量対応処理が行われればよい。例えば、インク補充処理部８１８またはカートリッジ交換処理部８２０が設けられていれば、印刷動作制御部８１６は印刷動作の停止処理を行わなくてもよい。また、上記に例示した以外の低インク量対応処理を行う構成であって、インク不足による不適切な動作を回避する構成が設けられてもよい。
【０２３７】
また、上記の低インク量対応処理は、最も低い位置の液体センサが液面通過を検知してから「所定の余裕量」の印刷が行われた後に実行することが好適である。「所定の余裕量」は、液体センサの液面検知後に全インクを消費する印刷量より少ない適当な値に設定される。
【０２３８】
図４７を参照すると、液体センサ８０６が検出するのはインクニアエンド状態である。液体センサ８０６の検出後も、少量のインクが残っている。この形態によれば、インクをさらに消費してから、すなわちできるだけインクを使い切ってから低インク量対応処理を実行することができる。
【０２３９】
上記の「所定の余裕量」は、印刷枚数で定義されてもよい。たとえば、一番下の液体センサが液面通過を検出してから低インク量対応処理の実行までの印刷枚数が予め設定される。この形態によれば、あるページの印刷途中で低インク量対応処理を実行することが回避される。あるページの印刷途中で印刷を停止したり、印刷途中でカートリッジ交換処理を開始することが回避される。したがって、低インク量対応処理を適切なタイミングで行うことができる。
【０２４０】
「センサの走査による液面把握」
図４９は、本発明のもうひとつの実施の形態に係る記録装置制御システムを示している。インクカートリッジ９００は、縦長形状を有し、例えばいわゆるオフキャリッジ用の固定型インクカートリッジである。インクカートリッジ９００は、インク消費による液面低下方向に沿って七つの液体センサ９０２〜９１４を有している。液体センサ９０２〜９１４は、記録装置制御部８１０の計測処理部８１２により制御される。各液体センサの動作は、図４７の実施形態と実質的に同様である。計測処理部８１２は、各液体センサに駆動電圧を与えるとともに、各センサが出力する逆起電圧を得る。
【０２４１】
計測処理部８１２は、所定の計測間隔をおいて定期的にインクの液面位置を検出する。毎回の検出処理のたびに、液体センサ９０２〜９１４が使用される。例えば、最も上の液体センサ９０２から最も下の液体センサ９１４へ向けて順番に液体センサが動作する（液体センサのスキャン動作）。仮に液面が液体センサ９１０と液体センサ９１２の間にあったとする。この場合、液体センサ９０２〜９１０は、インク空状態を検出する。一方、液体センサ９１２および液体センサ９１４は、インク有り状態を検出する。したがって、液面位置を正確にもとめることができる。なお液体センサのスキャン方向は逆向きでもよい。
【０２４２】
計測処理部８１２は、すでに液面が通過した検出位置にある液体センサを使わないでもよい。例えば図４９の例では、液体センサ９０２〜９１０はすでに液面が通過した位置にあるので、検出処理に使われないでもよい。ここで、所定の回数にわたってインク空状態を検出した液体センサが、検出処理の対象から除外されてもよい。これにより、液面より上にあることが確実な液体センサを検出処理の対象から外すことができる。
【０２４３】
計測処理部８１２は、好ましくは、検出処理に使わない液体センサが増えたときに、検出頻度を増大する。検出処理に使わない液体センサが増えたということは、液面が低下したことを意味する。液面が低下してインクが少なくなったとき、検出頻度の増大により、インク消費を早めに検出できる。センサ数が減っているので、計測処理部の負担の増大も少ない。したがって、この形態によれば、検出処理の負担の増大を抑えつつ、インクが少なくなったときにインク消費をより早く検出できる。
【０２４４】
好適な一形態においては、インクの消費が進む途中で、液体センサのスキャン方向が切り換えられる。図５０は、スキャン方向の切り換え処理を示している。所定の検出方向切り換えレベル９２０（スキャン方向切り換えレベル）が予め設定されている。この例では、切り換えレベル９２０は液体センサ９０８の高さと一致している。液体センサ９０８はインクカートリッジのほぼ中央にある。液面が切り換えレベル９２０より上にあるときは、スキャン方向は下向きである。したがって、最初に液体センサ９０２が動作し、次に液体センサ９０４が動作し、順次下側のセンサが動作する。一方、インク消費が進み、液面が切り換えレベル９２０を下回ると、すなわち液体センサ９０８がインク空状態を検出すると、液体センサのスキャン方向が上向きへと切り換えられる。まず、液体センサ９１４が動作して次に液体センサ９１２が動作し、順次上側のセンサが動作する。
【０２４５】
ここで、液面が高いときは、上から下へ液面を探す方が、より早く液面を見つけられる。逆に液面が低いときは、下から上に液面を探すと、より早く液面を見つけられる。したがって本実施の形態によれば効率よく液面位置を把握できる。
【０２４６】
またこの形態では、液面位置を把握できたら、予定の全ての検出位置での検出を終了する前でも、液体検出を終了してしまってよい。たとえば図５０の左側では、液体センサ９０６がインク有り状態を検出したら、液面位置が分かったので、検出処理を終了してもよい。
【０２４７】
上記の説明から明らかなように、本実施の形態によれば、液面の位置を効率よく早く見つけることができ、さらには無駄な液体センサの動作を減らせる。
【０２４８】
なお、切り換えレベル９２０は、カートリッジの中央でなくてもよい。また、切り換えレベル９２０は、中央のセンサと同じ位置でなくてもよい。
【０２４９】
「印刷動作中のセンサ使用制限」
好ましくは、インクジェット記録装置が印刷動作中か否かによって、計測制御処理が変更される。印刷動作中は、検出に用いる液体センサの数が制限される。これは、検出結果に基づく記録装置制御が可能な範囲で制限された情報を入手すべく、通常よりも少ない数の液体センサを使用する処理である。
【０２５０】
好ましくは、印刷動作中は最も下の液体センサ（図４９、９１４）のみが使用される。この最も下の液体センサを用いて、インクが残り少なくなったか否かのみが判断される。印刷動作中でなければ、上述した処理にしたがって他の液体センサも使用される。
【０２５１】
この形態の利点を説明する。印刷動作中は、インク消費検出処理の負担をできるだけ軽くすることが望ましい。例えば、図４９の記録装置制御部８１０は、検出処理と印刷動作を制御する。検出処理は、印刷動作にも影響を与える可能性がある。検出処理が簡単な方が、印刷処理が速やかに進むと考えられる。本実施の形態によれば、有用な情報が得られる範囲で液体センサの動作を制限するので、印刷動作中の検出処理の負担を軽くできる。
【０２５２】
センサ動作の制限の形態については各種の変形が可能である。例えば、液体センサが適当に間引かれる。奇数番目あるいは偶数番目の液体センサのみが使われてもよい。また、一番上、真中および一番下の液体センサのみが使われてもよい。また、次に液面通過を検出すると予想される液体センサのみが使われてもよい。図４９の例では、印刷動作中は液体センサ９１２のみが使用される。
【０２５３】
「フェール対策」
さらに、本実施の形態では、プリンタフェール対策として以下の処理を行う。図５１は、本実施形態のフェール対策を示している。図中において白い丸印は、液体センサがインク空状態を検出したことを示す。黒い丸印は、液体センサがインク有り状態を検出したことを示す。図示のように、上側の三つの液体センサ９０２〜９０６は、インク空状態を検出している。４番目の液体センサ９０８はインク有り状態を検出する。しかしながら、５番目の液体センサ９１０はインク空状態を検出している。さらに下側の二つの液体センサ９１２、９１４はインク有り状態を検出している。
【０２５４】
このとき、液体センサ９０８または液体センサ９１０にフェールが発生したと考えられる。しかしながら、どちらの液体センサにフェールが発生したかは判別できない。そこで、本実施形態では、液面が液体センサ９１０と液体センサ９１２の間にあると判断する。これは、複数の液体センサにフェールの可能性があるときに、より上側の液体センサがフェールしたと判断することを意味している。このような判断により、液面が低く推定されるので、誤判断による弊害を最小限に抑えることができる。
【０２５５】
以上、本発明を実施の形態を用いて説明したが、本発明の技術的範囲は上記実施の形態に記載の範囲には限定されない。上記実施の形態に、多様な変更又は改良を加えることができる。その様な変更又は改良を加えた形態も本発明の技術的範囲に含まれ得ることが、特許請求の範囲の記載から明らかである。
【０２５６】
例えば本実施形態では本発明がインクカートリッジに適用された。これに対して、本発明は、インクカートリッジに限定されず、他のインクタンクまたはインク容器に適用されてもよく、またインク以外の液体を収容する容器に適用されてもよい。
【０２５７】
また上記の実施の形態では、液体センサが振動を発生するとともに、インク消費状態を示す検出信号を発生した。一つの手法では、振動の発生後、残留振動状態を示す信号が出力された。別の手法では、振動による弾性波の発生後、反射波に応じた信号が出力された。これに対して、液体センサは自分で振動を発生しないでもよい。すなわち、振動発生と検出信号出力の両方を行わないもよい。別のアクチュエータによって振動が発生される。あるいは、キャリッジの移動などに伴ってインクカートリッジに振動が発生したときに、インク消費状態を示す検出信号を液体センサが生成してもよい。積極的に振動を発生することなく、プリンタ動作によって自然に発生する振動を用いてインク消費が検出される。
【０２５８】
【発明の効果】
以上の説明から明らかになるように、本発明によれば、液体容器内の液体消費状態が、圧電素子を利用して振動に基づき検出される。検出位置を切り換えることによって適切に液体消費状態を捕捉できる。さらに、液体消費状態に基づいてインクジェット記録装置を適切に制御することができる。
【図面の簡単な説明】
【図１】単色、例えばブラックインク用のインクカートリッジの一実施例を示す図である。
【図２】複数種類のインクを収容するインクカートリッジの一実施例を示す図である。
【図３】図１及び２に示したインクカートリッジに適したインクジェット記録装置の一実施例を示す図である。
【図４】サブタンクユニット３３の詳細な断面を示す図である。
【図５】弾性波発生手段３、１５、１６、及び１７の製造方法を示す図である。
【図６】図５に示した弾性波発生手段３の他の実施形態を示す図である。
【図７】本発明のインクカートリッジの他の実施例を示す図である。
【図８】本発明のインクカートリッジの更に他の実施例を示す図である。
【図９】本発明のインクカートリッジの更に他の実施例を示す図である。
【図１０】本発明のインクカートリッジの更に他の実施例を示す図である。
【図１１】本発明のインクカートリッジの更に他の実施形態を示す図である。
【図１２】図１１に示したインクカートリッジの他の実施形態を示す図である。
【図１３】本発明のインクカートリッジの更に他の実施形態を示す図である。
【図１４】貫通孔１ｃの更に他の実施形態の平面を示す図である。
【図１５】本発明のインクジェット記録装置の実施形態の断面を示す図である。
【図１６】図１５に示した記録装置に適したインクカートリッジの実施形態を示す図である。
【図１７】本発明のインクカートリッジ２７２の他の実施形態を示す図である。
【図１８】本発明のインクカートリッジ２７２及びインクジェット記録装置の更に他の実施形態を示す図である。
【図１９】図１６に示したインクカートリッジ２７２の他の実施形態を示す図である。
【図２０】アクチュエータ１０６の詳細を示す図である。
【図２１】アクチュエータ１０６の周辺およびその等価回路を示す図である。
【図２２】インクの密度とアクチュエータ１０６によって検出されるインクの共振周波数との関係を示す図である。
【図２３】アクチュエータ１０６の逆起電力波形を示す図である。
【図２４】アクチュエータ１０６の他の実施形態を示す図である。
【図２５】図２４に示したアクチュエータ１０６の一部分の断面を示す図である。
【図２６】図２６に示したアクチュエータ１０６の全体の断面を示す図である。
【図２７】図２４に示したアクチュエータ１０６の製造方法を示す図である。
【図２８】本発明のインクカートリッジの更に他の実施形態を示す図である。
【図２９】貫通孔１ｃの他の実施形態を示す図である。
【図３０】アクチュエータ６６０の他の実施形態を示す図である。
【図３１】アクチュエータ６７０の更に他の実施形態を示す図である。
【図３２】モジュール体１００を示す斜視図である。
【図３３】図３２に示したモジュール体１００の構成を示す分解図である。
【図３４】モジュール体１００の他の実施形態を示す図である。
【図３５】図３４に示したモジュール体１００の構成を示す分解図である。
【図３６】モジュール体１００の更に他の実施形態を示す図である。
【図３７】図３２に示したモジュール体１００をインク容器１に装着した断面の例を示す図である。
【図３８】モジュール体１００の更に他の実施形態を示す図である。
【図３９】図２０および図２１に示したアクチュエータ１０６を用いたインクカートリッジ及びインクジェット記録装置の実施形態を示す図である。
【図４０】インクジェット記録装置の詳細を示す図である。
【図４１】図４０に示したインクカートリッジ１８０の他の実施形態を示す図である。
【図４２】インクカートリッジ１８０の更に他の実施形態を示す図である。
【図４３】インクカートリッジ１８０の更に他の実施形態を示す図である。
【図４４】インクカートリッジ１８０の更に他の実施形態を示す図である。
【図４５】図４４（Ｃ）に示したインクカートリッジ１８０の他の実施形態を示す図である。
【図４６】モジュール体１００を用いたインクカートリッジの更に他の実施形態を示す図である。
【図４７】本実施の形態にかかるインクジェット記録装置の制御システムを示す図である。
【図４８】インク消費状態を表示するときに表示形態を異ならせる処理の例を示す図である。
【図４９】本実施の形態に係るもう１つのインクジェット記録装置の制御システムを示す図である。
【図５０】図４８のシステムにおいて、インク消費過程で液面位置の検出方向を切り換える処理を示す図である。
【図５１】図４８のシステムにおけるセンサフェール対策処理を示す図である。
【符号の説明】
８００ インクカートリッジ
８０２〜８０６ 液体センサ
８１０ 記録装置制御部
８１２ 計測処理部
８１４ 提示処理部
８１６ 印刷動作制御部
８１８ インク補充処理部
８２０ カートリッジ交換処理部
８２２ 印刷データ記憶処理部
９００ インクカートリッジ
９０２〜９１４ 液体センサ[0001]
BACKGROUND OF THE INVENTION
The present invention includes a piezoelectric device for detecting a change in acoustic impedance, and in particular, detecting a change in resonance frequency, and in particular, detecting a liquid consumption state in a liquid container that contains the liquid. More specifically, the liquid container is provided in an ink cartridge that is applied to an ink jet recording apparatus that performs printing by ejecting ink droplets from nozzle openings by pressurizing ink in a pressure generating chamber in accordance with print data by pressure generating means. The present invention relates to a piezoelectric device that detects a consumption state of ink in an ink cartridge.
[0002]
[Prior art]
An example of an ink cartridge mounted on an ink jet recording apparatus will be described as a liquid container to which the present invention is applied. In general, an ink jet recording apparatus includes a carriage on which an ink jet recording head including a pressure generating unit that pressurizes a pressure generating chamber, a nozzle opening that discharges pressurized ink as ink droplets from a nozzle opening, And an ink tank that stores ink supplied to the recording head via the path, and is configured to be capable of continuous printing. The ink tank is generally configured as a cartridge that is detachable from the recording apparatus so that the user can easily replace the ink tank when the ink is consumed.
[0003]
Conventionally, as a method for managing ink consumption of an ink cartridge, the number of ink droplets ejected by the recording head and the amount of ink sucked in the maintenance process of the print head are integrated by software, and the ink consumption is calculated. There have been known a method for managing, a method for managing ink consumption by detecting when a predetermined amount of ink is actually consumed by attaching two electrodes for detecting a liquid level directly to an ink cartridge, and the like.
[0004]
However, the method of managing the ink consumption by calculating the number of ink droplets ejected and the amount of ink sucked by software is calculated depending on the usage environment, for example, the temperature and humidity in the use room, after the ink cartridge is opened. The pressure in the ink cartridge and the viscosity of the ink change due to the elapsed time and the usage frequency on the user side, resulting in a non-negligible error between the calculated ink consumption and the actual consumption. There was a problem that. Further, when the same cartridge is once removed and remounted, the accumulated count value is once reset, so that there is a problem that the actual ink remaining amount cannot be known at all.
[0005]
On the other hand, the method of managing the point in time when ink is consumed by the electrode can detect the actual amount of ink at one point, so that the remaining amount of ink can be managed with high reliability. However, in order to detect the ink level, the ink must be conductive, which limits the type of ink used. In addition, there is a problem that the liquid-tight structure between the electrode and the ink cartridge is complicated. Furthermore, since a noble metal having high conductivity and high corrosion resistance is usually used as the electrode material, there is a problem that the manufacturing cost of the ink cartridge is increased. Furthermore, since it is necessary to mount the two electrodes in different locations of the ink cartridge, there is a problem that the manufacturing process increases and as a result, the manufacturing cost increases.
[0006]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide a liquid container that can solve the above-described problems, can accurately detect a liquid consumption state, and does not require a complicated seal structure. Another object of the present invention is to provide an ink cartridge that can accurately detect the ink consumption state and does not require a complicated seal structure.
[0007]
In particular, the present invention provides a technique for detecting the remaining amount of liquid using vibration, and particularly provides a technique that can appropriately supplement the consumption of liquid. Also, the detection operation is reduced. Thus, for example, in the recording apparatus, the printing operation process is prevented from being affected by the detection process, such as being interrupted. Furthermore, the present invention provides a method for appropriately controlling the printing apparatus based on the detected ink consumption state. The present invention is not limited to ink consumption detection of an ink cartridge, but can be applied to liquid detection of other liquid containers.
The above object can be achieved by a combination of features described in the independent claims. The dependent claims define further advantageous specific examples of the present invention.
[0008]
[Means for Solving the Problems]
(1) An aspect of the present invention is a liquid consumption detection method. This method is a liquid consumption detection method for detecting the consumption state of the liquid in the liquid container based on vibration using a piezoelectric element, and each of the detection positions at a plurality of detection positions along the liquid surface change direction. When a plurality of liquid sensors having piezoelectric elements are provided and the liquid level is higher than a predetermined detection direction switching level, the plurality of liquid sensors are used in order from the high detection position toward the low detection position, and the liquid level is in a predetermined detection direction. When the level is lower than the switching level, a change in the liquid level due to consumption of the liquid is detected by using a plurality of liquid sensors in order from the low detection position to the high detection position. When the liquid level is high, it is faster to find the liquid level from the top to the bottom. Conversely, when the liquid level is low, searching for the liquid level from the bottom to the top can find the liquid level more quickly. Therefore, according to the present invention, the liquid level position can be grasped efficiently with a small number of detection operations.
[0009]
Preferably, the method of the present invention increases the detection frequency according to the liquid level change. When the detection position is changed along the liquid level change direction, the detection frequency is increased.
[0010]
Preferably, a plurality of liquid sensors each having a piezoelectric element are provided corresponding to a plurality of detection positions along the liquid level change direction. There are two or more liquid sensors. After a liquid sensor detects the passage of the liquid level, the liquid sensor used for liquid detection is switched to the liquid level change direction.
[0011]
Preferably, the consumption state is detected based on a change in acoustic impedance accompanying the liquid consumption. The liquid sensor may output a signal indicating a residual vibration state after vibration is generated. The liquid consumption state is detected based on the residual vibration state changing according to the liquid consumption state.
[0012]
The liquid sensor may generate an elastic wave toward the inside of the liquid container and generate a signal corresponding to a reflected wave with respect to the elastic wave.
[0013]
An appropriate detection target is ink consumption of an ink cartridge mounted on the ink jet recording apparatus. However, the detection target is not limited to this.
[0014]
According to the present invention, since the detection position is switched in the liquid level change direction, the liquid consumption state can be efficiently supplemented with a small number of detection operations (use of sensors). Since the detection frequency increases as the detection position changes, the detection frequency when there is a lot of liquid can be reduced. Thereby, the total number of detection processes can be reduced.
[0015]
(2) A liquid consumption detection method according to another aspect of the present invention is a liquid consumption detection method for detecting a liquid consumption state in a liquid container based on vibration using a piezoelectric element. A plurality of liquid sensors each having a piezoelectric element are provided at a plurality of detection positions along the direction, and when the liquid level is higher than a predetermined detection direction switching level, the plurality of liquid sensors are sequentially arranged from the high detection position toward the low detection position. When the liquid level is lower than a predetermined detection direction switching level, a plurality of liquid sensors are used in order from the low detection position to the high detection position, and the liquid level is detected at a plurality of detection positions at each liquid detection. It is a liquid consumption detection method characterized by grasping a liquid level position by detecting passage. In this method, the liquid level passage is detected at a plurality of detection positions set along the liquid level change direction due to liquid consumption in each liquid detection. For example, liquid consumption is detected while scanning a plurality of detection positions. According to the present invention, the liquid level position can be grasped by detection at a plurality of detection positions.
[0016]
Preferably, the liquid surface position is obtained using a plurality of liquid sensors provided corresponding to the plurality of detection positions, each having a piezoelectric element. The liquid level position may be obtained without using the liquid sensor at the detection position where the liquid level has already passed. For example, the detection process is performed without using a liquid sensor that has not detected liquid for a predetermined number of times. Thereby, the load of the detection process can be reduced.
[0017]
Preferably, the detection frequency is increased when the number of liquid sensors used for detection decreases. A decrease in the number of liquid sensors used means that liquid consumption has progressed. According to the present invention, the liquid consumption information can be obtained quickly by increasing the detection frequency when the liquid is reduced. On the other hand, before the liquid consumption progresses, the detection frequency can be lowered to reduce the number of detection processes.
[0019]
If the liquid level position can be grasped, the liquid detection at that time may be ended even before the detection at all planned detection positions is ended. Furthermore, the detection operation can be reduced.
[0020]
Preferably, the consumption state is detected based on a change in acoustic impedance accompanying the liquid consumption. The liquid sensor may output a signal indicating a residual vibration state after vibration is generated. The liquid consumption state is detected based on the residual vibration state changing according to the liquid consumption state.
[0021]
The liquid sensor may generate an elastic wave toward the inside of the liquid container and generate a signal corresponding to a reflected wave with respect to the elastic wave.
[0022]
An appropriate detection target is ink consumption of an ink cartridge mounted on the ink jet recording apparatus. However, the detection target is not limited to this.
[0023]
The method of the present invention preferably limits the number of liquid sensors used for liquid detection during a printing operation by an inkjet recording device. The number of detection operations during printing can be reduced, and the printing process can be advanced promptly. Preferably, the liquid sensor at the lowest position is used during a printing operation by the inkjet recording apparatus, and a plurality of liquid sensors are used when the printing operation is not being performed. Detection operation during printing can be minimized. The liquid sensor used for detection may be thinned out.
[0024]
(3) Another aspect of the present invention is a recording apparatus control method for controlling an inkjet recording apparatus based on an ink consumption state of an ink container. This method is a recording apparatus control method for controlling an ink jet recording apparatus based on an ink consumption state of an ink container, and a piezoelectric element is provided at each of a plurality of detection positions set along a liquid level lowering direction of the ink. When the liquid level is higher than a predetermined detection direction switching level, a plurality of liquid sensors are used in order from the high detection position to the low detection position, and the liquid level is lower than the predetermined detection direction switching level. When the liquid level is low, the liquid level position is detected by detecting the passage of the liquid level based on vibration using a piezoelectric element using a plurality of liquid sensors in order from the low detection position to the high detection position. The inkjet recording apparatus is controlled according to the position. Preferably, the liquid surface position is obtained using a plurality of liquid sensors provided corresponding to a plurality of detection positions, each having a piezoelectric element.
[0025]
As the control process, information corresponding to the liquid sensor that has detected passage of the liquid level may be presented. The information may be displayed on the ink jet recording apparatus or outside thereof. Preferably, the display form is varied depending on the liquid sensor. The color of the information indicating the ink amount may be changed. Further, the graphic indicating the ink amount may be changed. In addition, a notification sound may be used for information presentation. Preferably, the notification sound is varied according to the liquid sensor. An audio signal may be generated as the notification sound.
[0026]
Further, as the control process, a predetermined low ink amount handling process may be performed in response to detection of the passage of the liquid level by the liquid sensor provided at the lowest position. The process corresponding to the low ink amount is, for example, (i) at least one of stopping the printing operation or prohibiting the print maintenance operation, or (ii) after completing a certain printing process (for example, printing a series of documents) and then performing the next printing. This is a process for prohibiting the process from proceeding. Further, for example, the low ink amount handling process is (iii) automatic refilling of ink into the ink container, (iv) automatic replacement of the ink container, or (v) storage of print data before completion of printing.
[0027]
The low ink amount handling process may be executed after a predetermined margin amount of printing is performed after the liquid sensor provided at the lowest position detects passage of the liquid level. The predetermined margin may be defined by the number of printed sheets.
[0028]
Preferably, the ink consumption state is detected based on a change in acoustic impedance accompanying ink consumption. The liquid sensor may output a signal indicating a residual vibration state after vibration is generated. The liquid consumption state is detected based on the residual vibration state changing according to the ink consumption state.
[0029]
The liquid sensor may generate an elastic wave toward the inside of the ink container and generate a signal corresponding to a reflected wave with respect to the elastic wave.
[0030]
The present invention is not limited to the method embodiment described above. For example, according to another aspect of the present invention, there is provided a liquid consumption detection device that detects a consumption state of a liquid in a liquid container based on vibration using a piezoelectric element, and a plurality of detection positions along a liquid surface change direction. Are provided with a plurality of liquid sensors each having a piezoelectric element, and when the liquid level is higher than a predetermined detection direction switching level, the plurality of liquid sensors are used in order from the high detection position to the low detection position. When the level is lower than the detection direction switching level, the liquid level detection device detects the liquid level position using a plurality of liquid sensors in order from the low detection position to the high detection position.
Further, the liquid consumption detecting device detects the consumption state of the liquid in the liquid container based on the vibration using the piezoelectric element, and has a plurality of piezoelectric elements respectively at a plurality of detection positions along the liquid surface change direction. When the liquid level is higher than a predetermined detection direction switching level, a plurality of liquid sensors are used in order from the high detection position to the low detection position, and when the liquid level is lower than the predetermined detection direction switching level. Using a plurality of liquid sensors in order from the low detection position to the high detection position, the liquid level position is grasped by detecting the passage of the liquid level at a plurality of detection positions at each liquid detection. And a liquid consumption detecting device.
Furthermore, the recording apparatus control system controls the ink jet recording apparatus based on the ink consumption state of the ink container, and a plurality of liquid sensors each having a piezoelectric element are provided at a plurality of detection positions along the liquid surface change direction. When the liquid level is higher than the predetermined detection direction switching level, a plurality of liquid sensors are used in order from the high detection position to the low detection position. When the liquid level is lower than the predetermined detection direction switching level, the low detection position is used. Using a plurality of liquid sensors in order toward the high detection position, the liquid level position is detected by detecting the passage of the liquid level based on the vibration using the piezoelectric element, and the ink jet recording apparatus according to the detected liquid level It can also be a recording apparatus control system characterized by controlling the above.
[0031]
The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the claimed invention, and all combinations of features described in the embodiments are the solution of the invention. It is not always essential to the means.
[0033]
First, the principle of this embodiment will be described. In the present embodiment, the present invention is applied to detection of an ink consumption state of an ink cartridge. The consumption state of ink is detected based on vibration using a piezoelectric element. The detection positions are set at a plurality of locations along the liquid level change direction due to liquid consumption (typically the liquid level lowering direction, and in this embodiment, the liquid level lowering direction is mainly assumed). A liquid sensor having a piezoelectric element is installed at each detection position. By using a plurality of detection positions, the ink consumption state can be detected at a plurality of stages.
[0034]
In the present embodiment, in particular, the detection position is switched along the liquid level lowering direction in accordance with the progress of ink consumption. For example, after one liquid sensor detects passage through a station surface, the use of the liquid sensor is stopped and the next lower liquid sensor is used. Such switching of the detection position eliminates the operation of the liquid sensor. That is, compared with the case where all the liquid sensors are always used, the operation of the liquid sensors is reduced and the burden of the detection process is reduced.
[0035]
In the present embodiment, the detection frequency increases as the detection position becomes lower. When the liquid level decreases, the decrease in the ink amount can be detected at an early stage by increasing the detection frequency. On the other hand, when the liquid level is still high, there is a margin in the amount of ink, so there is little need to detect ink consumption early. Therefore, the detection frequency is lowered when the liquid level is high. By changing the detection frequency according to the necessity of ink detection, the number of detection processes as a whole can be reduced.
[0036]
Thus, according to this embodiment, ink consumption can be tracked efficiently with a small number of detection operations. The burden of the ink consumption detection process is reduced, which is advantageous for the printing operation process.
[0037]
Hereinafter, the ink consumption detection technique of this embodiment will be described in more detail with reference to the drawings. First, a basic technique for ink consumption detection using a liquid sensor will be described. In this series of descriptions, an ink cartridge including a plurality of liquid sensors is shown. After describing various ink cartridges, detection position switching control according to the present embodiment will be described.
[0038]
In the present embodiment, the liquid sensor is specifically composed of a piezoelectric device. In the following description, “actuator” and “elastic wave generating means” correspond to a liquid sensor.
[0039]
"Cartridge for detecting ink consumption"
The basic concept of the present invention is to use the vibration phenomenon to determine the state of the liquid in the liquid container (including the presence or absence of the liquid in the liquid container, the amount of the liquid, the level of the liquid, the type of liquid, and the composition of the liquid). Is to detect. Several methods are conceivable for detecting the state of the liquid in the liquid container using a specific vibration phenomenon. For example, the elastic wave generating means generates an elastic wave to the inside of the liquid container, and receives a reflected wave reflected by the liquid surface or an opposing wall, thereby detecting a medium in the liquid container and a change in the state thereof. There is a way. In addition, there is a method for detecting a change in acoustic impedance from the vibration characteristics of a vibrating object. As a method of using a change in acoustic impedance, a vibration part of a piezoelectric device or an actuator having a piezoelectric element is vibrated, and then a counter electromotive force generated by residual vibration remaining in the vibration part is measured, whereby a resonance frequency or an inverse is obtained. A method for detecting a change in acoustic impedance by detecting the amplitude of an electromotive force waveform, or measuring a liquid impedance characteristic or an admittance characteristic with an impedance analyzer such as a measuring machine, for example, a transmission circuit, and a change in current value or voltage value or There is a method of measuring a change in current value or voltage value depending on the frequency when vibration is applied to a liquid. Details of the operating principles of the elastic wave generating means and the piezoelectric device or actuator will be described later.
[0040]
FIG. 1 is a cross-sectional view of an embodiment of an ink cartridge for a single color, for example, black ink to which the present invention is applied. The ink cartridge shown in FIG. 1 is based on a method of detecting the position of the liquid surface in the liquid container and the presence or absence of liquid by receiving the reflected wave of the elastic wave among the methods described above. Elastic wave generating means 3 is used as means for generating and receiving elastic waves. An ink supply port 2 that joins an ink supply needle of a recording apparatus is provided in a container 1 that stores ink. Outside the bottom surface 1a of the container 1, an elastic wave generating means 3 is attached so that the elastic wave can be transmitted to the ink inside through the container. When the ink K is almost consumed, that is, when the ink near end is reached, the elastic wave generating means 3 is positioned slightly above the ink supply port 2 so that the transmission of the elastic wave is changed from ink to gas. Is provided. Note that the receiving means may be provided separately, and the elastic wave generating means 3 may be simply used as the generating means.
[0041]
The ink supply port 2 is provided with a packing 4 and a valve body 6. As shown in FIG. 3, the packing 4 is fluid-tightly engaged with an ink supply needle 32 communicating with the recording head 31. The valve body 6 is always elastically contacted with the packing 4 by a spring 5. When the ink supply needle 32 is inserted, the valve body 6 is pushed by the ink supply needle 32 to open the ink flow path, and the ink in the container 1 passes through the ink supply port 2 and the ink supply needle 32 and the recording head 31. Supplied to. On the upper wall of the container 1, semiconductor storage means 7 that stores information about ink in the ink cartridge is mounted.
[0042]
FIG. 2 is a perspective view seen from the back side showing an embodiment of an ink cartridge containing a plurality of types of ink. The container 8 is divided into three ink chambers 9, 10 and 11 by a partition wall. Ink supply ports 12, 13 and 14 are formed in the respective ink chambers. Elastic wave generating means 15, 16 and 17 are attached to the bottom surfaces 8 a of the respective ink chambers 9, 10 and 11 so that the elastic waves can be transmitted to the ink accommodated in each ink chamber via the container 8. ing.
[0043]
FIG. 3 is a cross-sectional view showing an embodiment of the main part of an ink jet recording apparatus suitable for the ink cartridge shown in FIGS. The carriage 30 that can reciprocate in the width direction of the recording paper includes a sub tank unit 33, and the recording head 31 is provided on the lower surface of the sub tank unit 33. The ink supply needle 32 is provided on the ink cartridge mounting surface side of the sub tank unit 33.
[0044]
FIG. 4 is a cross-sectional view showing details of the sub tank unit 33. The sub tank unit 33 includes an ink supply needle 32, an ink chamber 34, a membrane valve 36, and a filter 37. Ink chamber 34 stores ink supplied from an ink cartridge via ink supply needle 32. The membrane valve 36 is designed to open and close due to a pressure difference between the ink chamber 34 and the ink supply path 35. The ink supply path 35 communicates with the recording head 31 so that ink is supplied to the recording head 31.
[0045]
As shown in FIG. 3, when the ink supply port 2 of the container 1 is inserted into the ink supply needle 32 of the sub tank unit 33, the valve body 6 moves backward against the spring 5, and an ink flow path is formed. Ink flows into the ink chamber 34. When the ink chamber 34 is filled with ink, a negative pressure is applied to the nozzle openings of the recording head 31 to fill the recording head 31 with ink, and then a recording operation is performed.
[0046]
When ink is consumed in the recording head 31 by the recording operation, the pressure on the downstream side of the membrane valve 36 decreases, so that the membrane valve 36 opens away from the valve body 38 as shown in FIG. By opening the membrane valve 36, the ink in the ink chamber 34 flows into the recording head 31 via the ink supply path 35. As the ink flows into the recording head 31, the ink in the container 1 flows into the sub tank unit 33 via the ink supply needle 32.
[0047]
During the operation period of the recording apparatus, a drive signal is supplied to the elastic wave generating means 3 at a preset detection timing, for example, at a constant period. The elastic wave generated by the elastic wave generating means 3 propagates through the bottom surface 1a of the container 1 and is transmitted to the ink, and propagates the ink.
[0048]
By sticking the elastic wave generating means 3 to the container 1, the ink cartridge itself can be provided with a remaining amount detecting function. According to the present invention, since there is no need to embed an electrode for detecting the liquid level when the container 1 is molded, the injection molding process is simplified, liquid leakage from the electrode embedding area is eliminated, and the reliability of the ink cartridge is improved. Can be improved.
[0049]
FIG. 5 shows a method for manufacturing the elastic wave generating means 3, 15, 16, and 17. The fixed substrate 20 is made of a fireable ceramic material or the like. First, as shown in FIG. 5I, a conductive material layer 21 to be one electrode is formed on the surface of the fixed substrate 20. Next, as shown in FIG. 5 (II), a green sheet 22 of piezoelectric material is overlaid on the surface of the conductive material layer 21. Next, as shown in FIG. 5 (III), the green sheet 22 is shaped into a predetermined shape by a press or the like, and is naturally dried, and then fired at a firing temperature, for example, 1200 ° C. Next, as shown in FIG. 5 (IV), a conductive material layer 23 to be the other electrode is formed on the surface of the green sheet 22 and is polarized so that it can be flexibly vibrated. Finally, as shown in FIG. 5 (V), the fixed substrate 20 is cut for each element. By fixing the fixed substrate 20 to a predetermined surface of the container 1 with an adhesive or the like, the elastic wave generating means 3 is fixed to the predetermined surface of the container 1, and the ink cartridge with the remaining amount detecting function is completed.
[0050]
FIG. 6 shows another embodiment of the elastic wave generating means 3 shown in FIG. In the embodiment of FIG. 5, the conductive material layer 21 is used as a connection electrode. On the other hand, in the embodiment of FIG. 6, the connection terminals 21a and 23a are formed by solder or the like at a position above the surface of the piezoelectric material layer formed by the green sheet 22. The connection terminals 21a and 23a allow the elastic wave generating means 3 to be directly mounted on the circuit board, and lead wires are not required to be routed.
[0051]
By the way, an elastic wave is a kind of wave which can propagate using gas, liquid, and solid as a medium. Accordingly, the wavelength, amplitude, phase, frequency, propagation direction, propagation speed, etc. of the elastic wave change due to changes in the medium. On the other hand, the reflected wave of the elastic wave also varies in the state and characteristics of the wave depending on the change of the medium. Therefore, it is possible to know the state of the medium by using the reflected wave that changes according to the change of the medium through which the elastic wave propagates. When detecting the state of the liquid in the liquid container by this method, for example, an elastic wave transceiver is used. The transmitter / receiver first applies an elastic wave to a medium, for example, a liquid or a liquid container, and the elastic wave propagates in the medium and reaches the surface of the liquid. Since the liquid surface has a boundary between the liquid and the gas, the reflected wave is returned to the transceiver. The transmitter / receiver receives the reflected wave, and the transmitter / receiver and the liquid surface are determined based on the return time of the reflected wave and the attenuation rate of the amplitude between the elastic wave generated by the transmitter and the reflected wave reflected by the liquid surface. Can be measured. By utilizing this, the state of the liquid in the liquid container can be detected. The elastic wave generating means 3 may be used as a transmitter / receiver in a method using a reflected wave due to a change of a medium through which the elastic wave propagates as a single unit, or may be equipped with a dedicated receiver.
[0052]
As described above, the elastic wave generated by the elastic wave generating means 3 and propagating through the ink liquid has the arrival time of the reflected wave generated on the surface of the ink liquid depending on the density of the ink liquid and the liquid level at the elastic wave generating means 3. Change. Therefore, when the composition of the ink is constant, the arrival time of the reflected wave generated on the ink liquid surface depends on the amount of ink. Therefore, the amount of ink can be detected by detecting the time from when the elastic wave generating means 3 generates an elastic wave until the reflected wave from the ink surface reaches the elastic wave generating means 3. In addition, since the elastic wave vibrates particles contained in the ink, it contributes to preventing precipitation of the pigment or the like in the case of pigment-based ink using a pigment as a colorant.
[0053]
By providing the elastic wave generating means 3 in the container 1, the ink in the ink cartridge decreases to near the ink end by the printing operation or the maintenance operation, and when the reflected wave cannot be received by the elastic wave generating means 3, the ink It can be determined that the ink cartridge is near-end, and the replacement of the ink cartridge can be prompted.
[0054]
FIG. 7 shows another embodiment of the ink cartridge of the present invention. A plurality of elastic wave generating means 41 to 44 are provided on the side wall of the container 1 at intervals in the vertical direction. The ink cartridge in FIG. 7 can detect the presence or absence of ink at the level of the mounting position of each of the elastic wave generating means 41 to 44 depending on whether or not the ink is present at each position of the elastic wave generating means 41 to 44. For example, when the water level of the ink is at a level between the elastic wave generating means 44 and 43, the elastic wave generating means 44 detects that there is no ink, and the elastic wave generating means 41, 42 and 43 Since it is detected that the ink is present, it can be seen that the water level of the ink is at a level between the elastic wave generating means 44 and 43. Therefore, by providing the plurality of elastic wave generating units 41 to 44, the remaining amount of ink can be detected in stages.
[0055]
8 and 9 show still other embodiments of the ink cartridge of the present invention. In the embodiment shown in FIG. 8, the elastic wave generating means 65 is mounted on the bottom surface 1a formed obliquely in the vertical direction. In the embodiment shown in FIG. 9, elastic wave generating means 66 extending in the vertical direction is provided in the vicinity of the bottom surface of the side wall 1b.
[0056]
8 and 9, when ink is consumed and a part of the elastic wave generating means 65 and 66 is exposed from the liquid surface, the elastic wave generating means 65 and 66 generate the elastic wave generated by the elastic wave generating means 65 and 66. The arrival time and acoustic impedance of the reflected wave continuously change corresponding to the changes Δh1 and Δh2 in the liquid level. Therefore, the process from the ink near-end state to the ink end of the remaining amount of ink can be accurately detected by detecting the arrival time of the reflected wave of the elastic wave or the degree of change in the acoustic impedance.
[0057]
In the above-described embodiments, an example of an ink cartridge that directly stores ink in a liquid container has been described. As another embodiment of the ink cartridge, the elastic wave generating means described above may be attached to an ink cartridge in which a porous elastic body is loaded in the container 1 and the porous elastic body is impregnated with liquid ink. In the above-described embodiments, the use of a flexural vibration type piezoelectric vibrator suppresses an increase in the size of the cartridge, but a longitudinal vibration type piezoelectric vibrator can also be used. Furthermore, in the above-described embodiment, an elastic wave is transmitted and received by the same elastic wave generating means. As another embodiment, the remaining ink amount may be detected by using different elastic wave generating means for transmitting and receiving waves.
[0058]
FIG. 10 shows still another embodiment of the ink cartridge of the present invention. A plurality of elastic wave generating means 65 a, 65 b and 65 c are provided in the container 1 at intervals in the vertical direction on a bottom surface 1 a formed obliquely in the vertical direction. According to this embodiment, the level of the mounting position of each elastic wave generating means 65a, 65b, and 65c depends on whether or not ink is present at each position of the plurality of elastic wave generating means 65a, 65b, and 65c. , The arrival times of the reflected waves of the elastic waves to the respective elastic wave generating means 65a, 65b and 65c are different. Accordingly, by scanning each elastic wave generating means 65 and detecting arrival times of reflected waves of the elastic waves at the elastic wave generating means 65a, 65b and 65c, the respective elastic wave generating means 65a, 65b and 65c are mounted. The presence or absence of ink at the position level can be detected. Therefore, it is possible to detect the remaining amount of ink step by step. For example, when the ink liquid level is at a level between the elastic wave generating means 65b and the elastic wave generating means 65c, the elastic wave generating means 65c detects the absence of ink, while the elastic wave generating means 65b and 65a indicate that ink is present. To detect. By comprehensively evaluating these results, it can be seen that the ink liquid level is located between the elastic wave generating means 65b and the elastic wave generating means 65c.
[0059]
FIG. 11 shows still another embodiment of the ink cartridge of the present invention. In the ink cartridge of FIG. 11, in order to increase the intensity of the reflected wave from the liquid surface, a plate material 67 is attached to the float 68 to cover the ink liquid surface. The plate material 67 is formed of a material having high acoustic impedance and ink resistance, such as a ceramic plate material.
[0060]
FIG. 12 shows another embodiment of the ink cartridge shown in FIG. In the ink cartridge of FIG. 12, similarly to the ink cartridge of FIG. 11, in order to increase the intensity of the reflected wave from the liquid surface, a plate material 67 is attached to the float 68 to cover the ink liquid surface. In FIG. 12A, the elastic wave generating means 65 is fixed to the bottom surface 1a formed obliquely in the vertical direction. When the remaining amount of ink is reduced and the elastic wave generating means 65 is exposed from the liquid surface, the arrival time of the reflected elastic wave generated by the elastic wave generating means 65 to the elastic wave generating means 65 changes. The presence or absence of ink at the level of the mounting position of the means 65 can be detected. Since the elastic wave generating means 65 is mounted on the bottom surface 1a formed obliquely in the vertical direction, even after the elastic wave generating means 65 detects that there is no ink, some ink remains in the container 1. From this, it is possible to detect the remaining amount of ink at the time of ink near end.
[0061]
In FIG. 12B, a plurality of elastic wave generating means 65a, 65b, and 65c are provided in the container 1 at intervals in the vertical direction on a bottom surface 1a formed obliquely in the vertical direction. According to the embodiment of FIG. 12B, each of the elastic wave generating means 65a, 65b and 65c depends on whether ink is present at each of the plurality of elastic wave generating means 65a, 65b and 65c. The arrival times of the reflected waves to the elastic wave generating means 65a, 65b and 65c at the mounting position level are different. Therefore, by scanning each elastic wave generating means 65 and detecting the arrival time of the reflected wave at each elastic wave generating means, the presence or absence of ink at the level of the mounting position of each elastic wave generating means 65a, 65b and 65c. Can be detected. For example, when the ink level is at a level between the elastic wave generating means 65b and the elastic wave generating means 65c, the elastic wave generating means 65c detects the absence of ink, while the elastic wave generating means 65b and 65a have ink. Is detected. By comprehensively evaluating these results, it can be seen that the ink liquid level is located between the elastic wave generating means 65b and the elastic wave generating means 65c.
[0062]
FIG. 13 shows still another embodiment of the ink cartridge of the present invention. In the ink cartridge shown in FIG. 13A, an ink absorber 74 is arranged so that at least part of the ink cartridge faces a through hole 1c provided in the container 1. The elastic wave generating means 70 is fixed to the bottom surface 1a of the container 1 so as to face the through hole 1c. In the ink cartridge shown in FIG. 13B, an ink absorber 75 is disposed so as to face a groove 1h formed in communication with the through hole 1c.
[0063]
According to the embodiment shown in FIG. 13, when the ink in the container 1 is consumed and the ink absorbers 74 and 75 are exposed from the ink, the ink in the ink absorbers 74 and 75 flows out by its own weight, and the ink is supplied to the recording head 31. Supply. When the ink is completely consumed, the ink absorbers 74 and 75 suck up the ink remaining in the through hole 1c, so that the ink is completely discharged from the concave portion of the through hole 1c. For this reason, the state of the reflected wave of the elastic wave generated by the elastic wave generating means 70 at the ink end changes, so that the ink end can be detected more reliably.
[0064]
FIG. 14 shows a plan view of still another embodiment of the through hole 1c. As shown in FIGS. 14A to 14C, the planar shape of the through hole 1c may be any shape such as a circle, a rectangle, and a triangle as long as the elastic wave generating means can be attached. .
[0065]
FIG. 15 shows a cross section of another embodiment of the ink jet recording apparatus of the present invention. FIG. 15A shows a cross section of only the ink jet recording apparatus. FIG. 15B shows a cross section when the ink cartridge 272 is attached to the ink jet recording apparatus. The carriage 250 that can reciprocate in the width direction of the inkjet recording paper has a recording head 252 on the lower surface. The carriage 250 has a sub tank unit 256 on the upper surface of the recording head 252. The sub tank unit 256 has the same configuration as the sub tank unit 33 shown in FIG. The sub tank unit 256 has an ink supply needle 254 on the mounting surface side of the ink cartridge 272. The carriage 250 has a convex portion 258 in a region where the ink cartridge 272 is mounted so as to face the bottom of the ink cartridge 272. The convex portion 258 has elastic wave generating means 260 such as a piezoelectric vibrator.
[0066]
FIG. 16 shows an embodiment of an ink cartridge suitable for the recording apparatus shown in FIG. FIG. 16A shows an embodiment of an ink cartridge for single color, for example, black ink. The ink cartridge 272 of this embodiment includes a container 274 that stores ink and an ink supply port 276 that is joined to the ink supply needle 254 of the recording apparatus. The container 274 has a concave portion 278 that engages with the convex portion 258 on the bottom surface 274a. The concave portion 278 accommodates an ultrasonic transmission material, for example, a gelling material 280.
[0067]
The ink supply port 276 includes a packing 282, a valve body 286, and a spring 284. The packing 282 engages with the ink supply needle 254 in a liquid-tight manner. The valve body 286 is always elastically contacted with the packing 282 by the spring 284. When the ink supply needle 254 is inserted into the ink supply port 276, the valve element 286 is pushed by the ink supply needle 254 to open the ink flow path. On the top of the container 274, a semiconductor storage means 288 that stores information relating to the ink and the like of the ink cartridge 272 is mounted.
[0068]
FIG. 16B shows an embodiment of an ink cartridge that contains a plurality of types of ink. The container 290 is divided into a plurality of regions, that is, three ink chambers 292, 294, 296 by walls. Each ink chamber 292, 294, and 296 has ink supply ports 298, 300, and 302. Gelling materials 304, 306, and 308 for transmitting the elastic waves generated by the elastic wave generating means 260 are formed in cylindrical recesses in regions facing the ink chambers 292, 294, and 296 on the bottom surface 290a of the container 290. 310, 312, and 314.
[0069]
As shown in FIG. 15B, when the ink supply port 276 of the ink cartridge 272 is inserted into the ink supply needle 254 of the sub tank unit 256, the valve element 286 moves backward against the spring 284 to form an ink flow path. Therefore, the ink in the ink cartridge 272 flows into the ink chamber 262. When the ink chamber 262 is filled with ink, a negative pressure is applied to the nozzle openings of the recording head 252 to fill the recording head 252 with ink, and then a recording operation is performed. When ink is consumed by the recording head 252 by the recording operation, the pressure on the downstream side of the membrane valve 266 decreases, so that the membrane valve 266 opens away from the valve body 270. The ink in the ink chamber 262 flows into the recording head 252 by opening the membrane valve 266. As the ink flows into the recording head 252, the ink in the ink cartridge 272 flows into the sub tank unit 256.
[0070]
During the operation period of the recording apparatus, a drive signal is supplied to the elastic wave generating means 260 at a preset detection timing, for example, at a constant period. The elastic wave generated by the elastic wave generating means 260 is radiated from the convex portion 258, propagates through the gelling material 280 on the bottom surface 274a of the ink cartridge 272, and is transmitted to the ink in the ink cartridge 272. In FIG. 15, the elastic wave generating means 260 is provided in the carriage 250, but the elastic wave generating means 260 may be provided in the sub tank unit 256.
[0071]
Since the elastic wave generated by the elastic wave generation means 260 propagates in the ink liquid, the time for the reflected wave reflected on the liquid surface to reach the elastic wave derivation means 260 depends on the density of the ink liquid and the liquid level of the ink. Change. Therefore, when the composition of the ink is constant, the arrival time of the reflected wave generated on the liquid surface depends only on the ink amount. Therefore, the amount of ink in the ink cartridge 272 can be detected by detecting the time until the reflected wave from the ink liquid surface after excitation of the elastic wave generating means 260 reaches the elastic wave generating means 260. The elastic wave generated by the elastic wave generating means 260 vibrates the particles contained in the ink, thereby preventing precipitation of pigments and the like.
[0072]
When the ink in the ink cartridge 272 decreases to near the ink end due to the printing operation or the maintenance operation, and the reflected wave from the surface of the ink liquid after the elastic wave generation by the elastic wave generating means 260 cannot be received, the ink near end Therefore, it is possible to prompt the user to replace the ink cartridge 272. When the ink cartridge 272 is not mounted on the carriage 250 as specified, the elastic wave propagation form by the elastic wave generating means 260 changes extremely. By utilizing this, when an extreme change in elastic wave is detected, an alarm can be issued to prompt the user to check the ink cartridge 272.
[0073]
The arrival time of the reflected elastic wave generated by the elastic wave generating means 260 to the elastic wave generating means 260 is affected by the density of the ink stored in the container 274. Since the ink density may differ depending on the type of ink, the data relating to the type of ink stored in the ink cartridge 272 is stored in the semiconductor storage unit 288, and a detection sequence corresponding to that is executed to execute the ink remaining. The amount can be detected more accurately.
[0074]
FIG. 17 shows another embodiment of the ink cartridge 272 of the present invention. The ink cartridge 272 shown in FIG. 17 has a bottom surface 274a formed obliquely in the vertical direction. In the ink cartridge 272 of FIG. 17, when the remaining amount of ink is reduced and a part of the elastic wave irradiation area of the elastic wave generating means 260 is exposed from the ink liquid surface, the reflected wave of the elastic wave generated by the elastic wave generating means 260 is obtained. The arrival time at the elastic wave generating means 260 continuously changes corresponding to the change Δh1 in the ink level. Δh1 indicates a difference in height of the bottom surface 274a at both ends of the gelling material 280. Therefore, by detecting the arrival time of the reflected wave to the elastic wave generating means 260, the process from the ink near end state to the ink end can be accurately detected.
[0075]
FIG. 18 shows still another embodiment of the ink cartridge 272 and the ink jet recording apparatus of the present invention. The ink jet recording apparatus of FIG. 18 has a convex portion 258 ′ on the side surface 274b of the ink cartridge 272 on the ink supply port 276 side. The convex portion 258 ′ includes elastic wave generating means 260 ′. A gelling material 280 ′ is provided on the side surface 274 b of the ink cartridge 272 so as to engage with the convex portion 258 ′. According to the ink cartridge 272 of FIG. 18, when the remaining amount of ink is reduced and a part of the elastic wave irradiation area of the elastic wave generating means 260 ′ is exposed from the liquid surface, the elastic wave generated by the elastic wave generating means 260 ′ is generated. The arrival time and acoustic impedance of the reflected wave to the elastic wave generating means 260 ′ continuously change corresponding to the change Δh2 in the liquid level. Δh2 represents the difference in height between the upper end and the lower end of the gelled material 280 ′. Therefore, the process from the ink near-end state to the ink end can be accurately detected by detecting the arrival time of the reflected wave to the elastic wave generating means 260 ′ or the degree of change in the acoustic impedance.
[0076]
In the above-described embodiment, an example of an ink cartridge in which ink is directly stored in the container 274 has been described. As another embodiment, the elastic wave generating means 260 may be applied to an ink cartridge in which a porous elastic body is loaded in the container 274 and the porous elastic body is impregnated with ink. Further, in the above-described embodiment, when detecting the remaining amount of ink based on the reflected wave on the liquid surface, the elastic wave is transmitted and received by the same elastic wave generating means 260 and 260 ′. The present invention is not limited to this. For example, as another embodiment, different elastic wave generating means 260 may be used for transmitting and receiving elastic waves.
[0077]
FIG. 19 shows another embodiment of the ink cartridge 272 shown in FIG. The ink cartridge 272 attaches the plate material 316 to the float 318 and covers the ink liquid surface, thereby increasing the intensity of the reflected wave from the ink liquid surface. The plate member 316 is preferably formed of a material having high acoustic impedance and ink resistance, such as ceramic.
[0078]
20 and 21 show details and an equivalent circuit of the actuator 106 which is an embodiment of the piezoelectric device. The actuator here is used in a method of detecting a consumption state of a liquid in a liquid container by detecting at least a change in acoustic impedance. In particular, it is used in a method for detecting a consumption state of liquid in a liquid container by detecting at least a change in acoustic impedance by detecting a resonance frequency by residual vibration. FIG. 20A is an enlarged plan view of the actuator 106. FIG. 20B shows a BB cross section of the actuator 106. FIG. 20C shows a CC cross section of the actuator 106. Further, FIGS. 21A and 21B show an equivalent circuit of the actuator 106. FIGS. 21C and 21D show the periphery including the actuator 106 and its equivalent circuit when the ink cartridge is filled with ink, respectively, and FIGS. 21E and 21F. ) Shows the periphery including the actuator 106 and its equivalent circuit when there is no ink in the ink cartridge.
[0079]
The actuator 106 includes a substrate 178 having a circular opening 161 at substantially the center, a vibration plate 176 disposed on one surface (hereinafter referred to as a surface) of the substrate 178 so as to cover the opening 161, and the vibration plate 176. The piezoelectric layer 160 disposed on the surface side, the upper electrode 164 and the lower electrode 166 sandwiching the piezoelectric layer 160 from both sides, the upper electrode terminal 168 electrically coupled to the upper electrode 164, and the lower electrode 166 electrically A lower electrode terminal 170 to be coupled and an auxiliary electrode 172 disposed between the upper electrode 164 and the upper electrode terminal 168 and electrically coupled to each other are provided. The piezoelectric layer 160, the upper electrode 164, and the lower electrode 166 each have a circular portion as a main part. Each circular portion of the piezoelectric layer 160, the upper electrode 164, and the lower electrode 166 forms a piezoelectric element.
[0080]
The diaphragm 176 is formed on the surface of the substrate 178 so as to cover the opening 161. The cavity 162 is formed by a portion facing the opening 161 of the vibration plate 176 and the opening 161 on the surface of the substrate 178. A surface of the substrate 178 opposite to the piezoelectric element (hereinafter referred to as a back surface) faces the liquid container side, and the cavity 162 is configured to come into contact with the liquid. The diaphragm 176 is liquid-tightly attached to the substrate 178 so that the liquid does not leak to the surface side of the substrate 178 even if the liquid enters the cavity 162.
[0081]
The lower electrode 166 is located on the surface of the vibration plate 176, that is, the surface opposite to the liquid container, and is attached so that the center of the circular portion which is the main part of the lower electrode 166 and the center of the opening 161 are substantially coincided with each other. It has been. The area of the circular portion of the lower electrode 166 is set to be smaller than the area of the opening 161. On the other hand, on the surface side of the lower electrode 166, the piezoelectric layer 160 is formed so that the center of the circular portion and the center of the opening 161 substantially coincide. The area of the circular portion of the piezoelectric layer 160 is set to be smaller than the area of the opening 161 and larger than the area of the circular portion of the lower electrode 166.
[0082]
On the other hand, on the surface side of the piezoelectric layer 160, the upper electrode 164 is formed so that the center of the circular portion which is the main part thereof substantially coincides with the center of the opening 161. The area of the circular portion of the upper electrode 164 is set to be smaller than the area of the circular portion of the opening 161 and the piezoelectric layer 160 and larger than the area of the circular portion of the lower electrode 166.
[0083]
Accordingly, the main part of the piezoelectric layer 160 is structured to be sandwiched between the main part of the upper electrode 164 and the main part of the lower electrode 166 from the front surface side and the back surface side, respectively. Deformation drive is possible. The circular portions that are the main portions of the piezoelectric layer 160, the upper electrode 164, and the lower electrode 166 form a piezoelectric element in the actuator 106. As described above, the piezoelectric element is in contact with the diaphragm 176. Of the circular portion of the upper electrode 164, the circular portion of the piezoelectric layer 160, the circular portion of the lower electrode 166, and the opening 161, the opening 161 has the largest area. With this structure, the vibration region of the diaphragm 176 that actually vibrates is determined by the opening 161. Further, since the circular portion of the upper electrode 164, the circular portion of the piezoelectric layer 160, and the circular portion of the lower electrode 166 have a smaller area than the opening 161, the diaphragm 176 is more likely to vibrate. Furthermore, of the circular portion of the lower electrode 166 and the circular portion of the upper electrode 164 that are electrically connected to the piezoelectric layer 160, the circular portion of the lower electrode 166 is smaller. Accordingly, the circular portion of the lower terminal 166 determines the portion of the piezoelectric layer 160 that generates the piezoelectric effect.
[0084]
The upper electrode terminal 168 is formed on the surface side of the diaphragm 176 so as to be electrically connected to the upper electrode 164 via the auxiliary electrode 172. On the other hand, the lower electrode terminal 170 is formed on the surface side of the diaphragm 176 so as to be electrically connected to the lower electrode 166. Since the upper electrode 164 is formed on the surface side of the piezoelectric layer 160, it is necessary to have a step equal to the sum of the thickness of the piezoelectric layer 160 and the thickness of the lower electrode 166 in the middle of connection with the upper electrode terminal 168. It is difficult to form the step with only the upper electrode 164, and even if possible, the connection state between the upper electrode 164 and the upper electrode terminal 168 becomes weak and there is a risk of disconnection. Therefore, the upper electrode 164 and the upper electrode terminal 168 are connected using the auxiliary electrode 172 as an auxiliary member. By doing so, the piezoelectric layer 160 and the upper electrode 164 are both supported by the auxiliary electrode 172, and a desired mechanical strength can be obtained, and the connection between the upper electrode 164 and the upper electrode terminal 168 is ensured. It becomes possible to.
[0085]
The vibration region facing the piezoelectric element in the piezoelectric element and the diaphragm 176 is a vibration part that actually vibrates in the actuator 106. Moreover, it is preferable that the members included in the actuator 106 are integrally formed by firing each other. By integrally forming the actuator 106, the handling of the actuator 106 becomes easy. Furthermore, the vibration characteristics are improved by increasing the strength of the substrate 178. That is, by increasing the strength of the substrate 178, only the vibration portion of the actuator 106 vibrates, and portions other than the vibration portion of the actuator 106 do not vibrate. Further, in order not to vibrate parts other than the vibration part of the actuator 106, the strength of the substrate 178 can be increased, whereas the piezoelectric element of the actuator 106 is made thin and small and the vibration plate 176 is made thin.
[0086]
As the material of the piezoelectric layer 160, it is preferable to use lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), or lead-free piezoelectric film that does not use lead, and the substrate 178 is made of zirconia or alumina. It is preferable to use it. Further, it is preferable to use the same material as the substrate 178 for the diaphragm 176. For the upper electrode 164, the lower electrode 166, the upper electrode terminal 168, and the lower electrode terminal 170, a conductive material, for example, a metal such as gold, silver, copper, platinum, aluminum, or nickel can be used.
[0087]
The actuator 106 configured as described above can be applied to a container that contains a liquid. For example, the ink cartridge can be attached to an ink cartridge or an ink tank used in an ink jet recording apparatus, or a container containing a cleaning liquid for cleaning the recording head.
[0088]
The actuator 106 shown in FIGS. 20 and 21 is mounted at a predetermined position of the liquid container so that the cavity 162 is in contact with the liquid contained in the liquid container. When the liquid is sufficiently contained in the liquid container, the inside of the cavity 162 and the outside thereof are filled with the liquid. On the other hand, when the liquid in the liquid container is consumed and the liquid level drops below the mounting position of the actuator, there is no liquid in the cavity 162, or liquid remains only in the cavity 162 and there is gas outside the cavity 162. It becomes a state to do. The actuator 106 detects at least a difference in acoustic impedance caused by the change in the state. Accordingly, the actuator 106 can detect whether the liquid is sufficiently contained in the liquid container or whether a certain amount of liquid is consumed. Furthermore, the actuator 106 can also detect the type of liquid in the liquid container.
[0089]
Here, the principle of the liquid level detection by the actuator will be described.
[0090]
In order to detect a change in the acoustic impedance of the medium, the impedance characteristic or admittance characteristic of the medium is measured. When measuring impedance characteristics or admittance characteristics, for example, a transmission circuit can be used. The transmission circuit applies a constant voltage to the medium, changes the frequency, and measures the current flowing through the medium. Alternatively, the transmission circuit supplies a constant current to the medium and changes the frequency to measure the voltage applied to the medium. A change in current value or voltage value measured by the transmission circuit indicates a change in acoustic impedance. In addition, a change in the frequency fm at which the current value or voltage value becomes maximum or minimum also indicates a change in acoustic impedance.
[0091]
Apart from the above method, the actuator can detect a change in the acoustic impedance of the liquid using a change only in the resonance frequency. When using the method of detecting the resonance frequency by measuring the counter electromotive force generated by the residual vibration remaining in the vibration part after the vibration part of the actuator vibrates as a method using the change in the acoustic impedance of the liquid, for example, A piezoelectric element can be used. The piezoelectric element is an element that generates a counter electromotive force due to residual vibration remaining in the vibration part of the actuator, and the magnitude of the counter electromotive force varies depending on the amplitude of the vibration part of the actuator. Therefore, detection is easier as the amplitude of the vibration part of the actuator is larger. In addition, the period in which the magnitude of the back electromotive force changes depends on the frequency of residual vibration in the vibration part of the actuator. Therefore, the frequency of the vibration part of the actuator corresponds to the frequency of the counter electromotive force. Here, the resonance frequency is a frequency in a resonance state between the vibration part of the actuator and the medium in contact with the vibration part.
[0092]
In order to obtain the resonance frequency fs, the waveform obtained by the back electromotive force measurement when the vibration part and the medium are in the resonance state is Fourier-transformed. The vibration of the actuator is not only deformed in one direction but is accompanied by various deformations such as deflection and extension, and therefore has various frequencies including the resonance frequency fs. Therefore, the resonance frequency fs is determined by Fourier-transforming the back electromotive force waveform when the piezoelectric element and the medium are in the resonance state and specifying the most dominant frequency component.
[0093]
The frequency fm is a frequency when the admittance of the medium is maximum or the impedance is minimum. Assuming the resonance frequency fs, the frequency fm causes a slight error with respect to the resonance frequency fs due to dielectric loss or mechanical loss of the medium. However, since it takes time to derive the resonance frequency fs from the actually measured frequency fm, the frequency fm is generally used instead of the resonance frequency. Here, by inputting the output of the actuator 106 to the transmission circuit, the actuator 106 can detect at least the acoustic impedance.
[0094]
A resonance specified by a method for measuring the frequency fm by measuring the impedance characteristic or admittance characteristic of the medium, and a method for measuring the resonance frequency fs by measuring the counter electromotive force generated by the residual vibration vibration in the vibration part of the actuator. Experiments have shown that there is little difference in frequency.
[0095]
The vibration region of the actuator 106 is a portion constituting the cavity 162 determined by the opening 161 of the vibration plate 176. When the liquid is sufficiently stored in the liquid container, the cavity 162 is filled with the liquid, and the vibration region comes into contact with the liquid in the liquid container. On the other hand, when there is not enough liquid in the liquid container, the vibration region is in contact with the liquid remaining in the cavity in the liquid container, or is not in contact with the liquid but is in contact with gas or vacuum.
[0096]
The actuator 106 of the present invention is provided with a cavity 162, whereby the liquid in the liquid container can be designed to remain in the vibration region of the actuator 106. The reason is as follows.
[0097]
Depending on the mounting position and mounting angle of the actuator on the liquid container, the liquid may adhere to the vibration area of the actuator even though the liquid level of the liquid in the liquid container is below the mounting position of the actuator. is there. When the actuator detects the presence or absence of liquid only by the presence or absence of liquid in the vibration region, the liquid attached to the vibration region of the actuator hinders accurate detection of the presence or absence of liquid. For example, when the liquid level is below the mounting position of the actuator, if the liquid container is swung due to the reciprocating movement of the carriage, etc. An erroneous determination is made that there is sufficient liquid in the liquid container. Therefore, conversely, even when the liquid remains there, by actively providing a cavity designed to accurately detect the presence or absence of the liquid, the liquid container oscillates and the liquid level undulates However, the malfunction of the actuator can be prevented. In this manner, malfunctions can be prevented by using an actuator having a cavity.
[0098]
Further, as shown in FIG. 21E, the case where there is no liquid in the liquid container and the liquid in the liquid container remains in the cavity 162 of the actuator 106 is set as the threshold value for the presence or absence of the liquid. That is, if there is no liquid around the cavity 162 and there is less liquid in the cavity than this threshold, it is determined that there is no ink. If there is liquid around the cavity 162 and there is more liquid than this threshold, ink is present. to decide. For example, when the actuator 106 is mounted on the side wall of the liquid container, it is determined that there is no ink when the liquid in the liquid container is below the mounting position of the actuator, and the liquid in the liquid container is above the mounting position of the actuator. In some cases, it is determined that ink is present. By setting the threshold in this way, it is determined that there is no ink even when the ink in the cavity has dried and the ink has run out. Even if it adheres to the cavity, the threshold value is not exceeded, so it can be determined that there is no ink.
[0099]
Here, the operation and principle of detecting the state of the liquid in the liquid container from the resonance frequency of the medium and the vibrating portion of the actuator 106 by measuring the back electromotive force will be described with reference to FIGS. In the actuator 106, a voltage is applied to the upper electrode 164 and the lower electrode 166 via the upper electrode terminal 168 and the lower electrode terminal 170, respectively. An electric field is generated in a portion of the piezoelectric layer 160 sandwiched between the upper electrode 164 and the lower electrode 166. The piezoelectric layer 160 is deformed by the electric field. When the piezoelectric layer 160 is deformed, the vibration region of the vibration plate 176 is flexibly vibrated. For a while after the piezoelectric layer 160 is deformed, the flexural vibration remains in the vibration portion of the actuator 106.
[0100]
The residual vibration is free vibration between the vibration part of the actuator 106 and the medium. Therefore, by setting the voltage applied to the piezoelectric layer 160 to a pulse waveform or a rectangular wave, it is possible to easily obtain the resonance state between the vibrating portion and the medium after the voltage is applied. The residual vibration causes the vibration portion of the actuator 106 to vibrate, so that the piezoelectric layer 160 is also deformed. Accordingly, the piezoelectric layer 160 generates a counter electromotive force. The counter electromotive force is detected through the upper electrode 164, the lower electrode 166, the upper electrode terminal 168 and the lower electrode terminal 170. Since the resonance frequency can be specified by the detected back electromotive force, the state of the liquid in the liquid container can be detected.
[0101]
In general, the resonant frequency fs is
fs = 1 / (2 * π * (M * Cact) ^1/2 (Formula 1)
It is represented by Here, M is the sum of the inertance Mact and the additional inertance M ′ of the vibration part. Cact is the compliance of the vibration part.
[0102]
FIG. 20C is a cross-sectional view of the actuator 106 when no ink remains in the cavity in this embodiment. 21A and 21B are equivalent circuits of the vibrating portion of the actuator 106 and the cavity 162 when no ink remains in the cavity.
[0103]
Mact is obtained by dividing the product of the thickness of the vibration part and the density of the vibration part by the area of the vibration part. In more detail, as shown in FIG.
Mact = Mpzt + Melectrode1 + Melectrode2 + Mvib (Formula 2)
It is expressed. Here, Mpzt is obtained by dividing the product of the thickness of the piezoelectric layer 160 and the density of the piezoelectric layer 160 in the vibrating portion by the area of the piezoelectric layer 160. Melectrode1 is obtained by dividing the product of the thickness of the upper electrode 164 and the density of the upper electrode 164 in the vibrating portion by the area of the upper electrode 164. Melectrode2 is obtained by dividing the product of the thickness of the lower electrode 166 and the density of the lower electrode 166 in the vibrating portion by the area of the lower electrode 166. Mvib is obtained by dividing the product of the thickness of the diaphragm 176 and the density of the diaphragm 176 in the vibration section by the area of the vibration region of the diaphragm 176. However, in this embodiment, Mact can be calculated from the thickness, density, and area of the entire vibration part. In this embodiment, each of the vibration regions of the piezoelectric layer 160, the upper electrode 164, the lower electrode 166, and the vibration plate 176 is obtained. Although the areas have the above-described magnitude relationship, the difference between the areas is preferably small. In the present embodiment, in the piezoelectric layer 160, the upper electrode 164, and the lower electrode 166, it is preferable that portions other than the circular portion, which is the main portion thereof, are so small as to be negligible with respect to the main portion. Accordingly, in the actuator 106, Mact is the sum of the inertances of the vibration regions of the upper electrode 164, the lower electrode 166, the piezoelectric layer 160 and the vibration plate 176. The compliance Cact is a compliance of a portion formed by the vibration region of the upper electrode 164, the lower electrode 166, the piezoelectric layer 160, and the vibration plate 176.
[0104]
21A, FIG. 21B, FIG. 21D, and FIG. 21F show equivalent circuits of the vibrating portion of the actuator 106 and the cavity 162. In these equivalent circuits, Cact is The compliance of the vibration part of the actuator 106 is shown. Cpzt, Celectrode1, Celectrode2, and Cvib respectively indicate the compliance of the piezoelectric layer 160, the upper electrode 164, the lower electrode 166, and the diaphragm 176 in the vibration part. Cact is expressed by Equation 3 below.
[0105]

From Equation 2 and Equation 3, FIG. 21A can also be expressed as FIG. 21B.
[0106]
The compliance Cact represents a volume that can receive the medium by deformation when pressure is applied to the unit area of the vibration part. The compliance Cact may be said to represent the ease of deformation.
[0107]
FIG. 21C is a cross-sectional view of the actuator 106 when the liquid is sufficiently contained in the liquid container and the liquid is filled around the vibration region of the actuator 106. M′max in FIG. 21C represents the maximum value of additional inertance when the liquid is sufficiently contained in the liquid container and the liquid is filled around the vibration region of the actuator 106. M 'max is
[0108]
M'max = (π * ρ / (2 * k ^Three )) * (2 * (2 * k * a) ^Three / (3 * π)) / (π * a ² ) ² (Formula 4)
(A is the radius of the vibration part, ρ is the density of the medium, and k is the wave number.)
[0109]
It is represented by Equation 4 is established when the vibration region of the actuator 106 is a circle having a radius a. The additional inertance M ′ is an amount indicating that the mass of the vibration part is apparently increased by the action of the medium in the vicinity of the vibration part. As can be seen from Equation 4, M′max varies greatly depending on the radius a of the vibrating portion and the density ρ of the medium.
[0110]
Wave number k is
k = 2 * π * fact / c (Formula 5)
(Fact is the resonance frequency of the vibrating part when the liquid is not touching. C is the speed of sound propagating through the medium.)
[0111]
It is represented by
[0112]
FIG. 21D shows an equivalent circuit of the vibration part of the actuator 106 and the cavity 162 in the case of FIG. 21C in which the liquid is sufficiently contained in the liquid container and the liquid is filled around the vibration region of the actuator 106. Indicates.
[0113]
FIG. 21E is a cross-sectional view of the actuator 106 when the liquid in the liquid container is consumed and there is no liquid around the vibration region of the actuator 106, but the liquid remains in the cavity 162 of the actuator 106. Show. Formula 4 is a formula representing the maximum inertance M′max determined from the density ρ of the ink, for example, when the liquid container is filled with liquid. On the other hand, when the liquid in the liquid container is consumed, and the liquid around the vibration region of the actuator 106 becomes gas or vacuum while the liquid remains in the cavity 162,
[0114]
M ′ = ρ * t / S (Formula 6)
It can be expressed. t is the thickness of the medium involved in the vibration. S is the area of the vibration region of the actuator 106. When this vibration region is a circle having a radius a, S = π * a ² It is. Therefore, the additional inertance M ′ follows the equation 4 when the liquid is sufficiently contained in the liquid container and the liquid is filled around the vibration region of the actuator 106. On the other hand, when the liquid is consumed and the liquid around the vibration region of the actuator 106 becomes a gas or a vacuum while the liquid remains in the cavity 162, Equation 6 is satisfied.
[0115]
Here, as shown in FIG. 21E, the liquid in the liquid container is consumed and there is no liquid in the vicinity of the vibration region of the actuator 106, but the liquid remains in the cavity 162 of the actuator 106. For the sake of convenience, the inertance M ′ is referred to as M′cav, and is distinguished from the additional inertance M′max in the case where liquid is filled around the vibration region of the actuator 106.
[0116]
FIG. 21F shows the case of FIG. 21E where the liquid in the liquid container is consumed and there is no liquid around the vibration region of the actuator 106, but the liquid remains in the cavity 162 of the actuator 106. 3 shows an equivalent circuit of the vibrating portion of the actuator 106 and the cavity 162.
[0117]
Here, the parameters related to the state of the medium are the density ρ of the medium and the thickness t of the medium in Equation 6. When the liquid is sufficiently stored in the liquid container, the liquid comes into contact with the vibrating portion of the actuator 106, and when the liquid is not sufficiently stored in the liquid container, the liquid remains in the cavity, Alternatively, gas or vacuum comes into contact with the vibrating portion of the actuator 106. When the liquid around the actuator 106 is consumed and the additional inertance in the process of shifting from M′max in FIG. 21C to M′cav in FIG. 21E is M ′ var, the liquid is contained in the liquid container. Since the thickness t of the medium changes depending on the state, the additional inertance M′var changes and the resonance frequency fs also changes. Therefore, the presence or absence of liquid in the liquid container can be detected by specifying the resonance frequency fs. Here, when t = d as shown in FIG. 21 (E), when M′cav is expressed using Equation 6, the cavity depth d is substituted for t in Equation 6,
[0118]
M′cav = ρ * d / S (Formula 7)
It becomes.
[0119]
Even if the mediums are different types of liquid, the density ρ varies depending on the composition, so that the additional inertance M ′ changes and the resonance frequency fs also changes. Therefore, the type of liquid can be detected by specifying the resonance frequency fs.
When only one of ink or air is in contact with the vibrating portion of the actuator 106 and they are not mixed, the difference in M ′ can be detected even if calculated by Equation 4.
[0120]
FIG. 22A is a graph showing the relationship between the amount of ink in the ink tank and the resonance frequency fs of the ink and the vibration part. Here, ink will be described as an example of liquid. The vertical axis represents the resonance frequency fs, and the horizontal axis represents the ink amount. When the ink composition is constant, the resonance frequency fs increases as the remaining ink amount decreases.
[0121]
When ink is sufficiently stored in the ink container, and the ink is filled around the vibration region of the actuator 106, the maximum additional inertance M′max is a value expressed by Equation 4. On the other hand, when the ink is consumed and the liquid remains in the cavity 162 and the ink is not filled around the vibration region of the actuator 106, the additional inertance M′var is expressed by the equation 6 based on the thickness t of the medium. Is calculated by Since t in Equation 6 is the thickness of the medium involved in the vibration, the ink gradually increases by making d of the cavity 162 of the actuator 106 (see FIG. 20B) small, that is, by making the substrate 178 sufficiently thin. It is also possible to detect the process of being consumed by the battery (see FIG. 21C). Here, tink is the thickness of the ink involved in vibration, and tink-max is the tink at M′max. For example, the actuator 106 is disposed almost horizontally with respect to the ink level on the bottom surface of the ink cartridge. When the ink is consumed and the ink level reaches the height of tink-max or less from the actuator 106, M′var gradually changes according to Equation 6, and the resonance frequency fs gradually changes according to Equation 1. Therefore, as long as the ink level is within the range t, the actuator 106 can gradually detect the ink consumption state.
[0122]
Further, by increasing or decreasing the vibration area of the actuator 106 and arranging it vertically, S in Equation 6 changes according to the position of the liquid level due to ink consumption. Therefore, the actuator 106 can also detect a process in which ink is gradually consumed. For example, the actuator 106 is disposed on the side wall of the ink cartridge substantially perpendicular to the ink level. When the ink is consumed and the ink level reaches the vibration region of the actuator 106, the additional inertance M ′ decreases as the water level decreases, so that the resonance frequency fs gradually increases according to Equation 1. Therefore, as long as the ink level is within the range of the diameter 2a of the cavity 162 (see FIG. 21C), the actuator 106 can gradually detect the ink consumption state.
[0123]
A curve X in FIG. 22A indicates the amount of ink stored in the ink tank and the ink and the ink when the cavity 162 of the actuator 106 is sufficiently shallow or the vibration region of the actuator 106 is sufficiently large or long. The relationship with the resonance frequency fs of a vibration part is represented. It can be understood that the amount of ink in the ink tank decreases and the resonance frequency fs of the ink and the vibration part gradually changes.
[0124]
More specifically, the case where the process in which ink is gradually consumed can be detected means that both liquid and gas having different densities exist in the vicinity of the vibration region of the actuator 106 and are involved in vibration. Is the case. As the ink is gradually consumed, the medium involved in the vibration around the vibration region of the actuator 106 increases the gas while decreasing the liquid. For example, when the actuator 106 is disposed horizontally with respect to the ink level and when tink is smaller than tink-max, the medium involved in the vibration of the actuator 106 includes both ink and gas. Therefore, when the area S of the vibration region of the actuator 106 is expressed as a state where M′max or less in Expression 4 is expressed by the additional mass of ink and gas,
[0125]
M ′ = M′air + M′ink = ρair * tair / S + ρink * tink / S (Formula 8)
It becomes. Here, M′air is an inertance of air, and M′ink is an inertance of ink. ρair is the density of air, and ρink is the density of ink. tair is the thickness of air involved in vibration, and tink is the thickness of ink involved in vibration. Among the media involved in vibration around the vibration region of the actuator 106, as the liquid decreases and the gas increases, the tair increases when the actuator 106 is arranged substantially horizontally with respect to the ink surface. Tink decreases. Thereby, M′var gradually decreases and the resonance frequency gradually increases. Therefore, it is possible to detect the amount of ink remaining in the ink tank or the amount of ink consumed. The reason why only the liquid density is calculated in Expression 7 is that it is assumed that the air density is negligibly small relative to the liquid density.
[0126]
In the case where the actuator 106 is disposed substantially perpendicular to the ink liquid level, the medium that is involved in the vibration of the actuator 106 is the ink only area and the medium that is involved in the vibration of the actuator 106 among the vibration areas of the actuator 106. It is considered as an equivalent circuit (not shown) in parallel with the gas region. If the medium related to the vibration of the actuator 106 is Sink and the area of the medium only related to the vibration of the actuator 106 is Sair, then Sair.
[0127]

It becomes.
[0128]
Equation 9 is applied when ink is not held in the cavity of the actuator 106. The case where ink is held in the cavity of the actuator 106 can be calculated by Equation 7, Equation 8, and Equation 9.
[0129]
On the other hand, when the substrate 178 is thick, that is, when the depth d of the cavity 162 is deep and d is relatively close to the medium thickness tink-max, or when the vibration region is very small compared to the height of the liquid container In practice, rather than detecting a process in which the ink gradually decreases, it is detected that the ink level is higher than the actuator mounting position. In other words, the presence or absence of ink in the vibration region of the actuator is detected. For example, the curve Y in FIG. 22A shows the relationship between the amount of ink in the ink tank and the resonance frequency fs of the ink and the vibration part in the case of a small circular vibration region. A state is shown in which the ink and the resonance frequency fs of the vibrating part change drastically between the ink amount Q before and after the ink level in the ink tank passes through the mounting position of the actuator. From this, it is possible to detect whether or not a predetermined amount of ink remains in the ink tank.
[0130]
FIG. 22B shows the relationship between the ink density and the resonance frequency fs of the ink and the vibration part on the curve Y in FIG. Ink is used as an example of the liquid. As shown in FIG. 22B, when the ink density is increased, the added inertance is increased, so that the resonance frequency fs is decreased. That is, the resonance frequency fs varies depending on the type of ink. Therefore, by measuring the resonance frequency fs, it is possible to confirm whether or not inks having different densities are mixed when refilling the ink.
[0131]
That is, it is possible to identify ink tanks containing different types of ink.
[0132]
Subsequently, the conditions under which the liquid state can be accurately detected when the size and shape of the cavity are set so that the liquid remains in the cavity 162 of the actuator 106 even when the liquid in the liquid container is empty. Detailed description. If the actuator 106 can detect the liquid state when the cavity 162 is filled with the liquid, the actuator 106 can detect the liquid state even when the cavity 162 is not filled with the liquid.
[0133]
The resonance frequency fs is a function of the inertance M. The inertance M is the sum of the inertance Mact and the additional inertance M ′ of the vibration part. Here, the additional inertance M ′ is related to the liquid state. The additional inertance M ′ is an amount indicating that the mass of the vibration part is apparently increased by the action of the medium in the vicinity of the vibration part. That is, it means an increase in mass of the vibrating part due to apparent absorption of the medium by the vibration of the vibrating part.
[0134]
Therefore, when M′cav is larger than M′max in Equation 4, all the medium that apparently absorbs is the liquid remaining in the cavity 162. Therefore, it is the same as the state where the liquid container is filled with the liquid. In this case, since M ′ does not change, the resonance frequency fs also does not change. Therefore, the actuator 106 cannot detect the state of the liquid in the liquid container.
[0135]
On the other hand, when M′cav is smaller than M′max in Equation 4, the medium that apparently absorbs is the liquid remaining in the cavity 162 and the gas or vacuum in the liquid container. At this time, unlike the state in which the liquid container is filled with liquid, M ′ changes, so the resonance frequency fs changes. Therefore, the actuator 106 can detect the state of the liquid in the liquid container.
[0136]
That is, when the liquid in the liquid container is empty and the liquid remains in the cavity 162 of the actuator 106, the condition under which the actuator 106 can accurately detect the liquid state is that M′cav is higher than M′max. It is small. Note that the condition M′max> M′cav that allows the actuator 106 to accurately detect the liquid state is not related to the shape of the cavity 162.
[0137]
Here, M′cav is the mass of the liquid having a volume approximately equal to the volume of the cavity 162. Therefore, from the inequality M′max> M′cav, the condition under which the actuator 106 can accurately detect the liquid state can be expressed as the condition of the capacity of the cavity 162. For example, when the radius of the opening 161 of the circular cavity 162 is a and the depth of the cavity 162 is d,
[0138]
M'max> ρ * d / πa ² (Formula 10)
It is. Expanding Equation 10
[0139]
a / d> 3 * π / 8 (Formula 11)
This condition is required. Expressions 10 and 11 are valid only when the shape of the cavity 162 is circular. Using the formula of M′max when not circular, πa in formula 10 ² Can be calculated by substituting for the area, and the relationship between the dimension such as the width and length of the cavity and the depth can be derived.
[0140]
Therefore, if the actuator 106 has the cavity 162 having the radius a of the opening 161 and the depth d of the cavity 162 satisfying Expression 11, the liquid in the liquid container is empty and the liquid is contained in the cavity 162. Even if it remains, the liquid state can be detected without malfunction.
[0141]
Since the additional inertance M ′ also affects the acoustic impedance characteristics, it can be said that the method of measuring the counter electromotive force generated in the actuator 106 due to the residual vibration detects at least a change in acoustic impedance.
[0142]
Further, according to this embodiment, the back electromotive force generated in the actuator 106 due to the subsequent residual vibration after the actuator 106 generates vibration is measured. However, it is not always necessary for the vibrating portion of the actuator 106 to vibrate the liquid by its own vibration caused by the drive voltage. That is, even if the vibration part does not oscillate by itself, the piezoelectric layer 160 is bent and deformed by vibrating with a certain range of liquid in contact therewith. This residual vibration generates a counter electromotive force voltage in the piezoelectric layer 160 and transmits the counter electromotive force voltage to the upper electrode 164 and the lower electrode 166. The state of the medium may be detected by using this phenomenon. For example, in an ink jet recording apparatus, even if the state of the ink tank or the ink in the ink tank is detected by using the vibration around the vibration part of the actuator generated by the vibration caused by the reciprocating movement of the carriage by the scanning of the print head during printing Good.
[0143]
FIGS. 23A and 23B show a residual vibration waveform of the actuator 106 and a method for measuring the residual vibration after the actuator 106 is vibrated. The upper and lower levels of the ink water level at the mounting position level of the actuator 106 in the ink cartridge can be detected by a change in the frequency or amplitude of the residual vibration after the actuator 106 oscillates. In FIGS. 23A and 23B, the vertical axis represents the voltage of the counter electromotive force generated by the residual vibration of the actuator 106, and the horizontal axis represents time. The residual vibration of the actuator 106 generates a voltage analog signal waveform as shown in FIGS. 23 (A) and 23 (B). Next, the analog signal is converted into a digital numerical value corresponding to the frequency of the signal.
[0144]
In the example shown in FIGS. 23A and 23B, the presence or absence of ink is detected by measuring the time during which four pulses from the fourth pulse to the eighth pulse of the analog signal occur.
[0145]
More specifically, after the actuator 106 oscillates, the number of times that a predetermined reference voltage set in advance is crossed from the low voltage side to the high voltage side is counted. The digital signal is set to High between 4 counts and 8 counts, and the time from 4 counts to 8 counts is measured by a predetermined clock pulse.
[0146]
FIG. 23A shows a waveform when the ink level is higher than the mounting position level of the actuator 106. On the other hand, FIG. 23B shows a waveform when there is no ink at the mounting position level of the actuator 106. Comparing FIG. 23A and FIG. 23B, it can be seen that FIG. 23A has a longer time from 4 counts to 8 counts than FIG. 23B. In other words, the time from 4 counts to 8 counts varies depending on the presence or absence of ink. By using this time difference, it is possible to detect the ink consumption state. The reason for counting from the fourth count of the analog waveform is to start measurement after the vibration of the actuator 106 is stabilized. The count from the fourth count is merely an example, and the count may be counted from an arbitrary count. Here, signals from the 4th count to the 8th count are detected, and the time from the 4th count to the 8th count is measured by a predetermined clock pulse. Thereby, the resonance frequency is obtained. The clock pulse is preferably a clock pulse equal to a clock for controlling a semiconductor memory device or the like attached to the ink cartridge. Note that it is not necessary to measure the time up to the 8th count, and it may be counted up to an arbitrary count. In FIG. 23, the time from the 4th count to the 8th count is measured, but the time within different count intervals may be detected according to the circuit configuration for detecting the frequency.
[0147]
For example, when the ink quality is stable and the fluctuation of the peak amplitude is small, the resonance frequency may be obtained by detecting the time from the 4th count to the 6th count in order to increase the detection speed. . When the ink quality is unstable and the fluctuation of the pulse amplitude is large, the time from the 4th count to the 12th count may be detected in order to accurately detect the residual vibration.
[0148]
As another example, the wave number of the voltage waveform of the back electromotive force within a predetermined period may be counted (not shown). The resonance frequency can also be obtained by this method. More specifically, after the actuator 106 oscillates, the digital signal is set to High for a predetermined period, and the number of times the predetermined reference voltage is crossed from the low voltage side to the high voltage side is counted. The presence or absence of ink can be detected by measuring the count number.
[0149]
Further, as can be seen by comparing FIG. 23A and FIG. 23B, the amplitude of the back electromotive force waveform between when the ink is filled in the ink cartridge and when the ink is not inside the ink cartridge. Is different. Therefore, the ink consumption state in the ink cartridge may be detected by measuring the amplitude of the counter electromotive force waveform without obtaining the resonance frequency. More specifically, for example, a reference voltage is set between the peak of the counter electromotive force waveform in FIG. 23A and the peak of the counter electromotive force waveform in FIG. After the actuator 106 oscillates, the digital signal is set to High at a predetermined time, and if the back electromotive force waveform crosses the reference voltage, it is determined that there is no ink. If the back electromotive force waveform does not cross the reference voltage, it is determined that ink is present.
[0150]
FIG. 24 shows a method for manufacturing the actuator 106. A plurality of actuators 106 (four in the example of FIG. 24) are integrally formed. The actuator 106 shown in FIG. 25 is manufactured by cutting the integrally molded product of the plurality of actuators shown in FIG. 24 at each actuator 106. When the piezoelectric elements of the plurality of integrally formed actuators 106 shown in FIG. 24 are circular, the actuator 106 shown in FIG. 20 can be manufactured by cutting the integrally formed product at each actuator 106. By integrally forming the plurality of actuators 106, the plurality of actuators 106 can be efficiently manufactured at the same time, and handling during transportation becomes easy.
[0151]
The actuator 106 includes a thin plate or vibration plate 176, a substrate 178, an elastic wave generating means or piezoelectric element 174, a terminal forming member or upper electrode terminal 168, and a terminal forming member or lower electrode terminal 170. The piezoelectric element 174 includes a piezoelectric diaphragm or piezoelectric layer 160, an upper electrode or upper electrode 164, and a lower electrode or lower electrode 166. A vibration plate 176 is formed on the upper surface of the substrate 178, and a lower electrode 166 is formed on the upper surface of the vibration plate 176. A piezoelectric layer 160 is formed on the upper surface of the lower electrode 166, and an upper electrode 164 is formed on the upper surface of the piezoelectric layer 160. Therefore, the main part of the piezoelectric layer 160 is formed so as to be sandwiched from above and below by the main part of the upper electrode 164 and the main part of the lower electrode 166.
[0152]
A plurality of (four in the example of FIG. 24) piezoelectric elements 174 are formed on the vibration plate 176. A lower electrode 166 is formed on the surface of the diaphragm 176, a piezoelectric layer 160 is formed on the surface of the lower electrode 166, and an upper electrode 164 is formed on the upper surface of the piezoelectric layer 160. Upper electrode terminals 168 and lower electrode terminals 170 are formed at the ends of the upper electrode 164 and the lower electrode 166. The four actuators 106 are cut separately and used individually.
[0153]
FIG. 25 shows a cross section of a part of the actuator 106 having a rectangular piezoelectric element.
[0154]
FIG. 26 shows an overall cross section of the actuator 106 shown in FIG. A through hole 178 a is formed on the surface of the substrate 178 facing the piezoelectric element 174. The through hole 178a is sealed by the vibration plate 176. The diaphragm 176 is made of an elastically deformable material such as alumina or zirconia oxide. A piezoelectric element 174 is formed on the vibration plate 176 so as to face the through hole 178a. The lower electrode 166 is formed on the surface of the diaphragm 176 so as to extend in one direction from the region of the through hole 178a, to the left in FIG. The upper electrode 164 is formed on the surface of the piezoelectric layer 160 so as to extend from the region of the through hole 178a in the direction opposite to the lower electrode, and to the right in FIG. The upper electrode terminal 168 and the lower electrode terminal 170 are formed on the upper surfaces of the auxiliary electrode 172 and the lower electrode 166, respectively. The lower electrode terminal 170 is in electrical contact with the lower electrode 166, and the upper electrode terminal 168 is in electrical contact with the upper electrode 164 through the auxiliary electrode 172, so that a signal between the piezoelectric element and the outside of the actuator 106 can be transmitted. Deliver it. The upper electrode terminal 168 and the lower electrode terminal 170 have a height equal to or higher than the height of the piezoelectric element in which the electrode and the piezoelectric layer are combined.
[0155]
FIG. 27 shows a manufacturing method of the actuator 106 shown in FIG. First, the through-hole 940a is drilled in the green sheet 940 using a press or laser processing. The green sheet 940 becomes the substrate 178 after firing. The green sheet 940 is formed of a material such as ceramic. Next, the green sheet 941 is laminated on the surface of the green sheet 940. The green sheet 941 becomes the diaphragm 176 after firing. The green sheet 941 is formed of a material such as zirconia oxide. Next, a conductive layer 942, a piezoelectric layer 160, and a conductive layer 944 are sequentially formed on the surface of the green sheet 941 by a method such as pressure film printing. The conductive layer 942 later becomes the lower electrode 166, and the conductive layer 944 later becomes the upper electrode 164. Next, the formed green sheet 940, green sheet 941, conductive layer 942, piezoelectric layer 160, and conductive layer 944 are dried and fired. The spacer members 947 and 948 raise the height of the upper electrode terminal 168 and the lower electrode terminal 170 to be higher than the piezoelectric element. The spacer members 947 and 948 are formed by printing the same material as the green sheets 940 and 941 or by laminating green sheets. The spacer members 947 and 948 can reduce the material of the upper electrode terminal 168 and the lower electrode terminal 170, which are noble metals, and can reduce the thickness of the upper electrode terminal 168 and the lower electrode terminal 170. The electrode terminal 170 can be printed with high accuracy, and the height can be further stabilized.
[0156]
If the connection portion 944 ′ with the conductive layer 944 and the spacer members 947 and 948 are formed at the same time when the conductive layer 942 is formed, the upper electrode terminal 168 and the lower electrode terminal 170 can be easily formed or firmly fixed. Finally, an upper electrode terminal 168 and a lower electrode terminal 170 are formed in end regions of the conductive layer 942 and the conductive layer 944. When the upper electrode terminal 168 and the lower electrode terminal 170 are formed, the upper electrode terminal 168 and the lower electrode terminal 170 are formed so as to be electrically connected to the piezoelectric layer 160.
[0157]
FIG. 28 shows still another embodiment of an ink cartridge to which the present invention is applied. FIG. 28A is a cross-sectional view of the bottom of the ink cartridge according to the present embodiment. The ink cartridge of the present embodiment has a through hole 1c on the bottom surface 1a of the container 1 that stores ink. The bottom of the through-hole 1c is closed by the actuator 650 to form an ink reservoir.
[0158]
FIG. 28B shows a detailed cross section of the actuator 650 and the through hole 1c shown in FIG. FIG. 28C shows a plan view of the actuator 650 and the through hole 1c shown in FIG. The actuator 650 has a diaphragm 72 and a piezoelectric element 73 fixed to the diaphragm 72. The actuator 650 is fixed to the bottom surface of the container 1 so that the piezoelectric element 73 faces the through hole 1c through the vibration plate 72 and the substrate 71. The diaphragm 72 is elastically deformable and has ink resistance.
[0159]
Depending on the amount of ink in the container 1, the amplitude and frequency of the counter electromotive force generated by the residual vibration of the piezoelectric element 73 and the diaphragm 72 change. A through hole 1c is formed at a position facing the actuator 650, and a minimum amount of ink is secured in the through hole 1c. Therefore, the ink end of the container 1 can be reliably detected by measuring in advance the vibration characteristics of the actuator 650 determined by the amount of ink secured in the through hole 1c.
[0160]
FIG. 29 shows another embodiment of the through hole 1c. In each of FIGS. 29A, 29B, and 29C, the left figure shows a state where no ink K is present in the through hole 1c, and the right figure shows a state where the ink K remains in the through hole 1c. Indicates. In the embodiment of FIG. 28, the side surface of the through hole 1c is formed as a vertical wall. In FIG. 29 (A), the through hole 1c has a side surface 1d that is slanted in the vertical direction and is open to the outside. In FIG. 29B, stepped portions 1e and 1f are formed on the side surface of the through hole 1c. The upper step portion 1f is wider than the lower step portion 1e. In FIG. 29C, the through hole 1c has a groove 1g extending in the direction in which the ink K is easily discharged, that is, in the direction of the ink supply port 2.
[0161]
According to the shape of the through hole 1c shown in FIGS. 29A to 29C, the amount of ink K in the ink reservoir can be reduced. Accordingly, since M ′ cav described in FIGS. 20 and 21 can be made smaller than M′max, the vibration characteristics of the actuator 650 at the ink end can be determined by the amount of ink K that can be printed on the container 1. Since it can be greatly different from the remaining case, the ink end can be detected more reliably.
[0162]
FIG. 30 is a perspective view showing another embodiment of the actuator. The actuator 660 has a packing 76 outside the through hole 1c of the substrate or the mounting plate 78 constituting the actuator 660. A caulking hole 77 is formed on the outer periphery of the actuator 660. The actuator 660 is fixed to the container 1 by caulking through the caulking hole 77.
[0163]
31A and 31B are perspective views showing still another embodiment of the actuator. In the present embodiment, the actuator 670 includes a recess forming substrate 80 and a piezoelectric element 82. A recess 81 is formed on one surface of the recess forming substrate 80 by a technique such as etching, and a piezoelectric element 82 is attached to the other surface. Of the recess forming substrate 80, the bottom of the recess 81 acts as a vibration region. Therefore, the vibration region of the actuator 670 is defined by the peripheral edge of the recess 81. Further, the actuator 670 is similar to the structure in which the substrate 178 and the diaphragm 176 are integrally formed in the actuator 106 according to the embodiment of FIG. Accordingly, the manufacturing process can be shortened when manufacturing the ink cartridge, and the cost is reduced. The actuator 670 has a size that can be embedded in the through hole 1 c provided in the container 1. Thereby, the recess 81 can also act as a cavity. Note that the actuator 106 according to the embodiment of FIG. 20 may be formed so as to be embedded in the through hole 1c in the same manner as the actuator 670 according to the embodiment of FIG.
[0164]
FIG. 32 is a perspective view showing a configuration in which the actuator 106 is integrally formed as the mounting module body 100. The module body 100 is attached to a predetermined portion of the container 1 of the ink cartridge. The module body 100 is configured to detect the consumption state of the liquid in the container 1 by detecting a change in at least the acoustic impedance in the ink liquid. The module body 100 of the present embodiment includes a liquid container mounting portion 101 for mounting the actuator 106 to the container 1. The liquid container mounting portion 101 has a structure in which a cylindrical portion 116 that houses an actuator 106 that oscillates in response to a drive signal is placed on a base 102 having a substantially rectangular plane. When the module body 100 is mounted on the ink cartridge, the actuator 106 of the module body 100 is configured so as not to contact from the outside, so that the actuator 106 can be protected from external contact. The leading edge of the cylindrical portion 116 is rounded so that it can be easily fitted into a hole formed in the ink cartridge.
[0165]
FIG. 33 is an exploded view showing the configuration of the module body 100 shown in FIG. The module body 100 includes a liquid container mounting portion 101 made of resin, and a piezoelectric device mounting portion 105 having a plate 110 and a recess 113. Further, the module body 100 includes lead wires 104a and 104b, an actuator 106, and a film 108. Preferably, the plate 110 is made of a material that hardly rusts, such as stainless steel or a stainless alloy. The cylindrical portion 116 and the base 102 included in the liquid container mounting portion 101 have an opening 114 formed at the center so that the lead wires 104a and 104b can be accommodated, and can accommodate the actuator 106, the film 108, and the plate 110. A recess 113 is formed. The actuator 106 is joined to the plate 110 via the film 108, and the plate 110 and the actuator 106 are fixed to the liquid container mounting portion 101. Accordingly, the lead wires 104 a and 104 b, the actuator 106, the film 108, and the plate 110 are attached to the liquid container attaching portion 101 as a unit. The lead wires 104a and 104b are coupled to the upper electrode and the lower electrode of the actuator 106, respectively, and transmit a drive signal to the piezoelectric layer, while transmitting a resonance frequency signal detected by the actuator 106 to a recording device or the like. The actuator 106 oscillates temporarily based on the drive signal transmitted from the lead wires 104a and 104b. The actuator 106 vibrates residually after oscillation, and generates back electromotive force by the vibration. At this time, the resonance frequency corresponding to the liquid consumption state in the liquid container can be detected by detecting the vibration period of the counter electromotive force waveform. The film 108 adheres the actuator 106 and the plate 110 to make the actuator liquid-tight. The film 108 is preferably formed of polyolefin or the like and bonded by heat fusion.
[0166]
The plate 110 has a circular shape, and the opening 114 of the base 102 is formed in a cylindrical shape. The actuator 106 and the film 108 are formed in a rectangular shape. The lead wire 104, the actuator 106, the film 108, and the plate 110 may be detachable from the base 102. The base 102, the lead wire 104, the actuator 106, the film 108, and the plate 110 are arranged symmetrically with respect to the central axis of the module body 100. Furthermore, the centers of the base 102, the actuator 106, the film 108, and the plate 110 are disposed on the substantially central axis of the module body 100.
[0167]
The area of the opening 114 of the base 102 is formed larger than the area of the vibration region of the actuator 106. A through hole 112 is formed at a position facing the vibration portion of the actuator 106 at the center of the plate 110. As shown in FIGS. 20 and 21, a cavity 162 is formed in the actuator 106, and the through hole 112 and the cavity 162 together form an ink reservoir. The thickness of the plate 110 is preferably smaller than the diameter of the through hole 112 in order to reduce the influence of residual ink. For example, it is preferable that the depth of the through hole 112 is not more than one third of the diameter. The through-hole 112 has a substantially perfect circular shape that is symmetric with respect to the central axis of the module body 100. The area of the through hole 112 is larger than the opening area of the cavity 162 of the actuator 106. The peripheral edge of the cross section of the through hole 112 may be a taper shape or a step shape. The module body 100 is mounted on the side, top, or bottom of the container 1 so that the through hole 112 faces the inside of the container 1. When the ink is consumed and the ink around the actuator 106 runs out, the resonance frequency of the actuator 106 changes greatly, so that a change in the ink level can be detected.
[0168]
FIG. 34 is a perspective view showing another embodiment of the module body. In the module body 400 of this embodiment, a piezoelectric device mounting portion 405 is formed in the liquid container mounting portion 401. In the liquid container mounting portion 401, a cylindrical column portion 403 is formed on a base 402 on a square whose plane is substantially rounded. Further, the piezoelectric device mounting portion 405 includes a plate-like element 406 and a concave portion 413 that stand on the cylindrical portion 403. The actuator 106 is disposed in the recess 413 provided on the side surface of the plate-like element 406. Note that the tip of the plate-like element 406 is chamfered at a predetermined angle so that it can be easily fitted into a hole formed in the ink cartridge.
[0169]
FIG. 35 is an exploded perspective view showing the configuration of the module body 400 shown in FIG. Similar to the module body 100 shown in FIG. 32, the module body 400 includes a liquid container mounting portion 401 and a piezoelectric device mounting portion 405. The liquid container mounting portion 401 has a base 402 and a cylindrical portion 403, and the piezoelectric device mounting portion 405 has a plate-like element 406 and a recess 413. The actuator 106 is joined to the plate 410 and fixed to the recess 413. The module body 400 further includes lead wires 404a and 404b, an actuator 106, and a film 408.
[0170]
According to the present embodiment, the plate 410 has a rectangular shape, and the opening 414 provided in the plate-like element 406 is formed in a rectangular shape. The lead wires 404 a and 404 b, the actuator 106, the film 408, and the plate 410 may be configured to be detachable from the base 402. The actuator 106, the film 408, and the plate 410 are disposed symmetrically with respect to a central axis that passes through the center of the opening 414 and extends in the vertical direction with respect to the plane of the opening 414. Further, the centers of the actuator 406, the film 408, and the plate 410 are disposed on the substantially central axis of the opening 414.
[0171]
The area of the through hole 412 provided at the center of the plate 410 is formed larger than the area of the opening of the cavity 162 of the actuator 106. The cavity 162 and the through hole 412 of the actuator 106 together form an ink reservoir. The thickness of the plate 410 is smaller than the diameter of the through hole 412, and is preferably set to a size equal to or less than one third of the diameter of the through hole 412, for example. The through hole 412 has a substantially perfect circular shape that is symmetric with respect to the central axis of the module body 400. The peripheral edge of the cross section of the through hole 412 may be a taper shape or a step shape. The module body 400 can be attached to the bottom of the container 1 such that the through hole 412 is disposed inside the container 1. Since the actuator 106 is arranged in the container 1 so as to extend in the vertical direction, the ink end point is set by changing the height of the base 402 and changing the height at which the actuator 106 is arranged in the container 1. Can be easily changed.
[0172]
FIG. 36 shows still another embodiment of the module body. Similar to the module body 100 shown in FIG. 32, the module body 500 of FIG. 36 includes a liquid container mounting portion 501 having a base 502 and a cylindrical portion 503. The module body 500 further includes lead wires 504a and 504b, an actuator 106, a film 508, and a plate 510. The base 502 included in the liquid container mounting portion 501 has an opening 514 at the center so as to accommodate the lead wires 504a and 504b, and a recess 513 so as to accommodate the actuator 106, the film 508, and the plate 510. Is done. The actuator 106 is fixed to the piezoelectric device mounting portion 505 via the plate 510. Accordingly, the lead wires 504a and 504b, the actuator 106, the film 508, and the plate 510 are integrally attached to the liquid container attachment portion 501. In the module body 500 of the present embodiment, a columnar portion 503 whose upper surface is slanted in the vertical direction is formed on a base on a square whose plane is substantially rounded. The actuator 106 is disposed on a recess 513 provided obliquely in the vertical direction on the upper surface of the cylindrical portion 503.
[0173]
The tip of the module body 500 is inclined, and the actuator 106 is mounted on the inclined surface. Therefore, when the module body 500 is mounted on the bottom or side of the container 1, the actuator 106 is inclined with respect to the vertical direction of the container 1. The inclination angle of the tip of the module body 500 is preferably between approximately 30 ° and 60 ° in view of detection performance.
[0174]
The module body 500 is mounted on the bottom or side of the container 1 so that the actuator 106 is disposed in the container 1. When the module body 500 is attached to the side portion of the container 1, the actuator 106 is attached to the container 1 so as to face the upper side, the lower side, or the lateral side of the container 1 while being inclined. On the other hand, when the module body 500 is mounted on the bottom of the container 1, it is preferable that the actuator 106 is attached to the container 1 so as to face the ink supply port side of the container 1 while being inclined.
[0175]
FIG. 37 is a cross-sectional view of the vicinity of the bottom of the ink container when the module body 100 shown in FIG. The module body 100 is mounted so as to penetrate the side wall of the container 1. An O-ring 365 is provided on the joint surface between the side wall of the container 1 and the module body 100 to keep the module body 100 and the container 1 liquid-tight. The module body 100 is preferably provided with a cylindrical portion as described in FIG. 32 so that the O-ring can be sealed. By inserting the tip of the module body 100 into the container 1, the ink in the container 1 comes into contact with the actuator 106 through the through hole 112 of the plate 110. Since the resonance frequency of the residual vibration of the actuator 106 differs depending on whether the surrounding of the vibration part of the actuator 106 is liquid or gas, the ink consumption state can be detected using the module body 100. Further, not only the module body 100 but also the module body 400 shown in FIG. 34, the module body 500 shown in FIG. 36, or the module bodies 700A and 700B and the mold structure 600 shown in FIG. The presence or absence of ink may be detected.
[0176]
FIG. 38A shows a cross-sectional view of the ink container when the module body 700B is mounted on the container 1. FIG. In this embodiment, the module body 700B is used as one of the mounting structures. The module 700B is mounted on the container 1 such that the liquid container mounting portion 360 protrudes into the container 1. A through hole 370 is formed in the mounting plate 350, and the through hole 370 faces the vibration portion of the actuator 106. Further, a hole 382 is formed in the bottom wall of the module body 700B, and a piezoelectric device mounting portion 363 is formed. Actuator 106 is deployed to block one of the holes 382. Therefore, the ink comes into contact with the vibration plate 176 through the hole 382 of the piezoelectric device mounting portion 363 and the through hole 370 of the mounting plate 350. The hole 382 of the piezoelectric device mounting portion 363 and the through hole 370 of the mounting plate 350 together form an ink reservoir. The piezoelectric device mounting portion 363 and the actuator 106 are fixed by a mounting plate 350 and a film member. A sealing structure 372 is provided at a connection portion between the liquid container mounting portion 360 and the container 1. The sealing structure 372 may be formed of a plastic material such as a synthetic resin, or may be formed of an O-ring. Although the module body 700B and the container 1 in FIG. 38A are separate bodies, the piezoelectric device mounting portion of the module body 700B may be configured as a part of the container 1 as shown in FIG.
[0177]
The module 700B in FIG. 38A does not require the lead wires shown in FIGS. 32 to 36 to be embedded in the module. Therefore, the molding process is simplified. Furthermore, the module body 700B can be replaced and recycled.
[0178]
When the ink cartridge is shaken, the ink adheres to the upper surface or the side surface of the container 1, and the ink dripping from the upper surface or the side surface of the container 1 may contact the actuator 106, so that the actuator 106 may malfunction. However, since the liquid container mounting portion 360 protrudes into the container 1 in the module 700B, the actuator 106 does not malfunction due to ink dripping from the upper surface or side surface of the container 1.
[0179]
In the embodiment of FIG. 38A, only a part of the vibration plate 176 and the mounting plate 350 is attached to the container 1 so as to come into contact with the ink in the container 1. In the embodiment of FIG. 38A, it is not necessary to embed the electrodes of the lead wires 104a, 104b, 404a, 404b, 504a, and 504b shown in FIGS. 32 to 36 in the module body. Therefore, the molding process is simplified. Furthermore, the actuator 106 can be replaced and recycled.
[0180]
FIG. 38B shows a cross-sectional view of an ink container as an example when the actuator 106 is mounted on the container 1. In the ink cartridge according to the embodiment of FIG. 38B, the protection member 361 is attached to the container 1 as a separate body from the actuator 106. Therefore, although the protection member 361 and the actuator 106 are not integrated as a module, the protection member 361 can protect the actuator 106 from being touched by the user's hand. A hole 380 provided in the front surface of the actuator 106 is disposed on the side wall of the container 1. The actuator 106 includes a piezoelectric layer 160, an upper electrode 164, a lower electrode 166, a vibration plate 176, and a mounting plate 350. A vibration plate 176 is formed on the upper surface of the mounting plate 350, and a lower electrode 166 is formed on the upper surface of the vibration plate 176. A piezoelectric layer 160 is formed on the upper surface of the lower electrode 166, and an upper electrode 164 is formed on the upper surface of the piezoelectric layer 160. Accordingly, the main part of the piezoelectric layer 160 is formed so as to be sandwiched from above and below by the main part of the upper electrode 164 and the main part of the lower electrode 166. The circular portions that are the main parts of the piezoelectric layer 160, the upper electrode 164, and the lower electrode 166 form a piezoelectric element. The piezoelectric element is formed on the vibration plate 176. The vibration region of the piezoelectric element and the diaphragm 176 is a vibration part where the actuator actually vibrates. A through hole 370 is provided in the mounting plate 350. Further, a hole 380 is formed in the side wall of the container 1. Therefore, the ink contacts the vibration plate 176 through the hole 380 of the container 1 and the through hole 370 of the mounting plate 350. The hole 380 of the container 1 and the through hole 370 of the mounting plate 350 together form an ink reservoir. In the embodiment of FIG. 38B, the actuator 106 is protected by the protective member 361, so that the actuator 106 can be protected from contact with the outside.
[0181]
In addition, it may replace with the attachment plate 350 in the Example of FIG. 38 (A) and (B), and may use the board | substrate 178 of FIG.
[0182]
FIG. 38C shows an embodiment including a mold structure 600 including the actuator 106. In this embodiment, a mold structure 600 is used as one of the attachment structures. The mold structure 600 includes an actuator 106 and a mold part 364. The actuator 106 and the mold part 364 are integrally formed. The mold part 364 is formed of a plastic material such as silicon resin. The mold part 364 has a lead wire 362 inside. Mold portion 364 is formed to have two legs extending from actuator 106. In order to fix the mold part 364 and the container 1 in a liquid-tight manner, the mold part 364 has two hemispherical ends of the mold part 364. The mold part 364 is mounted on the container 1 so that the actuator 106 protrudes into the container 1, and the vibration part of the actuator 106 contacts the ink in the container 1. The mold part 364 protects the upper electrode 164, the piezoelectric layer 160, and the lower electrode 166 of the actuator 106 from ink.
[0183]
The mold structure 600 in FIG. 38C does not require the sealing structure 372 between the mold part 364 and the container 1, so that the ink hardly leaks from the container 1. In addition, since the mold structure 600 does not protrude from the outside of the container 1, the actuator 106 can be protected from contact with the outside. When the ink cartridge is shaken, the ink is applied to the upper surface or the side surface of the container 1, and the ink dripping from the upper surface or the side surface of the container 1 contacts the actuator 106, so that the actuator 106 may malfunction. . In the mold structure 600, since the mold part 364 protrudes inside the container 1, the actuator 106 does not malfunction due to the ink dripping from the upper surface or the side surface of the container 1.
[0184]
FIG. 39 shows an embodiment of an ink cartridge and an ink jet recording apparatus using the actuator 106 shown in FIG. The plurality of ink cartridges 180 are mounted on an ink jet recording apparatus having a plurality of ink introduction portions 182 and holders 184 corresponding to the respective ink cartridges 180. The plurality of ink cartridges 180 accommodate different types of ink, for example, colors. On the bottom surface of each of the plurality of ink cartridges 180, an actuator 106 that is a means for detecting at least acoustic impedance is mounted. By mounting the actuator 106 on the ink cartridge 180, the remaining amount of ink in the ink cartridge 180 can be detected.
[0185]
FIG. 40 shows details of the periphery of the head portion of the ink jet recording apparatus. The ink jet recording apparatus includes an ink introduction unit 182, a holder 184, a head plate 186, and a nozzle plate 188. A plurality of nozzles 190 for ejecting ink are formed on the nozzle plate 188. The ink introduction part 182 has an air supply port 181 and an ink introduction port 183. The air supply port 181 supplies air to the ink cartridge 180. The ink introduction port 183 introduces ink from the ink cartridge 180. The ink cartridge 180 has an air introduction port 185 and an ink supply port 187. The air introduction port 185 introduces air from the air supply port 181 of the ink introduction unit 182. The ink supply port 187 supplies ink to the ink introduction port 183 of the ink introduction unit 182. When the ink cartridge 180 introduces air from the ink introduction part 182, the supply of ink from the ink cartridge 180 to the ink introduction part 182 is promoted. The holder 184 communicates the ink supplied from the ink cartridge 180 via the ink introduction unit 182 to the head plate 186.
[0186]
FIG. 41 shows another embodiment of the ink cartridge 180 shown in FIG. In the ink cartridge 180A of FIG. 41A, the actuator 106 is mounted on a bottom surface 194a formed obliquely in the vertical direction. Inside the ink container 194 of the ink cartridge 180, a wave barrier 192 is provided at a position facing the actuator 106 at a predetermined height from the inner bottom surface of the ink container 194. Since the actuator 106 is mounted obliquely with respect to the vertical direction of the ink container 194, the ink can be swept well.
[0187]
A gap filled with ink is formed between the actuator 106 and the wave barrier 192. Further, the interval between the wave preventing wall 192 and the actuator 106 is set to such an extent that the ink is not retained by the capillary force. When the ink container 194 rolls, an ink wave is generated inside the ink container 194 due to the roll, and the shock may cause the actuator 106 to malfunction because the actuator 106 detects a gas or a bubble. By providing the wave preventing wall 192, ink waves near the actuator 106 can be prevented, and malfunction of the actuator 106 can be prevented.
[0188]
The actuator 106 of the ink cartridge 180B shown in FIG. 41B is mounted on the side wall of the supply port of the ink container 194. The actuator 106 may be mounted on the side wall or bottom surface of the ink container 194 as long as it is in the vicinity of the ink supply port 187. The actuator 106 is preferably mounted at the center of the ink container 194 in the width direction. Since the ink passes through the ink supply port 187 and is supplied to the outside, providing the actuator 106 in the vicinity of the ink supply port 187 ensures that the ink and the actuator 106 come into contact until the ink near end point. Therefore, the actuator 106 can reliably detect the time point of the ink near end.
[0189]
Further, by providing the actuator 106 in the vicinity of the ink supply port 187, the positioning of the actuator 106 on the ink container and the contact on the carriage is ensured when the ink container is mounted on the cartridge holder on the carriage. The reason is that the most important in the connection between the ink container and the carriage is a reliable connection between the ink supply port and the supply needle. This is because even if there is a slight deviation, the tip of the supply needle is damaged, or the sealing structure such as the O-ring is damaged and the ink leaks out. In order to prevent such problems, an ink jet printer usually has a special structure that allows accurate alignment when an ink container is mounted on a carriage. Therefore, by arranging the actuator in the vicinity of the supply port, the alignment of the actuator can be ensured at the same time. Furthermore, by mounting the actuator 106 at the center in the width direction of the ink container 194, the alignment can be performed more reliably. This is because, when the ink container swings about the center line in the width direction when mounted on the holder, the vibration is least.
[0190]
FIG. 42 shows still another embodiment of the ink cartridge 180. 42A is a sectional view of the ink cartridge 180C, FIG. 42B is an enlarged sectional view of the side wall 194b of the ink cartridge 180C shown in FIG. 42A, and FIG. 42C is a front view thereof. FIG. In the ink cartridge 180C, the semiconductor storage means 7 and the actuator 106 are formed on the same circuit board 610. As shown in FIGS. 42B and 42C, the semiconductor memory means 7 is formed above the circuit board 610, and the actuator 106 is formed below the semiconductor memory means 7 on the same circuit board 610. Atypical O-ring 614 is attached to side wall 194b so as to surround actuator 106. A plurality of crimping portions 616 for joining the circuit board 610 to the ink container 194 are formed on the side wall 194b. The caulking unit 616 joins the circuit board 610 to the ink container 194, and presses the odd-shaped O-ring 614 against the circuit board 610, so that the vibration region of the actuator 106 can come into contact with the ink, and the outside of the ink cartridge. Keep inside and fluid tight.
[0191]
Terminals 612 are formed in the semiconductor memory means 7 and in the vicinity of the semiconductor memory means 7. The terminal 612 exchanges signals between the semiconductor storage means 7 and the outside of the ink jet storage device or the like. The semiconductor memory means 7 may be constituted by a rewritable semiconductor memory such as an EEPROM. Since the semiconductor storage means 7 and the actuator 106 are formed on the same circuit board 610, a single attachment process is sufficient when the actuator 106 and the semiconductor storage means 7 are attached to the ink cartridge 180C. Further, the work process at the time of manufacturing and recycling the ink cartridge 180C is simplified. Furthermore, since the number of parts is reduced, the manufacturing cost of the ink cartridge 180C can be reduced.
[0192]
The actuator 106 detects the ink consumption state in the ink container 194. The semiconductor storage means 7 stores ink information such as the remaining ink amount detected by the actuator 106. In other words, the semiconductor storage means 7 stores information on characteristic parameters such as the characteristics of ink and ink cartridges used for detection. The semiconductor storage unit 7 is configured to resonate when the ink in the ink container 194 is full, that is, when the ink is filled in the ink container 194 or at the end, that is, when the ink in the ink container 194 is consumed. Store the frequency as one of the characteristic parameters. The resonance frequency when the ink in the ink container 194 is full or in an end state may be stored when the ink container is first attached to the ink jet recording apparatus. Further, the resonance frequency when the ink in the ink container 194 is full or in an end state may be stored during the manufacture of the ink container 194. The resonance frequency when the ink in the ink container 194 is full or end is stored in the semiconductor storage unit 7 in advance, and the variation in detecting the remaining amount of ink is corrected by reading the resonance frequency data on the ink jet recording apparatus side. Therefore, it is possible to accurately detect that the ink remaining amount has decreased to the reference value.
[0193]
FIG. 43 shows still another embodiment of the ink cartridge 180. In the ink cartridge 180D shown in FIG. 43A, a plurality of actuators 106 are mounted on the side wall 194b of the ink container 194. A plurality of integrally molded actuators 106 shown in FIG. 24 are preferably used as the plurality of actuators 106. The plurality of actuators 106 are arranged on the side wall 194b at intervals in the vertical direction. By disposing a plurality of actuators 106 on the side wall 194b at intervals in the vertical direction, the remaining amount of ink can be detected stepwise.
[0194]
In the ink cartridge 180E shown in FIG. 43B, an actuator 606 that is long in the vertical direction is mounted on the side wall 194b of the ink container 194. A change in the remaining amount of ink in the ink container 194 can be continuously detected by the actuator 606 that is long in the vertical direction. The length of the actuator 606 is preferably at least half the height of the side wall 194b. In FIG. 43B, the actuator 606 has a length from the upper end to the lower end of the side wall 194b.
[0195]
In the ink cartridge 180F shown in FIG. 43C, a plurality of actuators 106 are mounted on the side wall 194b of the ink container 194 in the same manner as the ink cartridge 180D shown in FIG. A wave barrier 192 that is long in the vertical direction is provided. A plurality of integrally molded actuators 106 shown in FIG. 24 are preferably used as the plurality of actuators 106. A gap filled with ink is formed between the actuator 106 and the wave barrier 192. Further, the interval between the wave preventing wall 192 and the actuator 106 is set to such an extent that the ink is not retained by the capillary force. When the ink container 194 rolls, a wave of ink is generated inside the ink container 194 due to the roll, and gas or bubbles are detected by the actuator 106 due to the impact, and the actuator 106 may malfunction. By providing the wave preventing wall 192 as in the present invention, it is possible to prevent the ink from flowing near the actuator 106 and prevent the actuator 106 from malfunctioning. Further, the wave preventing wall 192 prevents bubbles generated by the ink swinging from entering the actuator 106.
[0196]
FIG. 44 shows still another embodiment of the ink cartridge 180. The ink cartridge 180G in FIG. 44A includes a plurality of partition walls 212 extending downward from the upper surface 194c of the ink container 194. Since the lower end of each partition wall 212 and the bottom surface of the ink container 194 are spaced apart from each other, the bottom of the ink container 194 communicates. The ink cartridge 180G has a plurality of storage chambers 213 defined by a plurality of partition walls 212, respectively. The bottoms of the plurality of storage chambers 213 communicate with each other. In each of the plurality of storage chambers 213, the actuator 106 is mounted on the upper surface 194 c of the ink container 194. The integrally formed actuator 106 shown in FIG. 24 is preferably used as the plurality of actuators 106. The actuator 106 is disposed approximately at the center of the upper surface 194 c of the storage chamber 213 of the ink container 194. The capacity of the storage chamber 213 is the largest on the ink supply port 187 side, and the capacity of the storage chamber 213 gradually decreases as the ink supply port 187 moves away from the ink container 194. Therefore, the interval at which the actuator 106 is disposed is wide on the ink supply port 187 side, and becomes narrower as the distance from the ink supply port 187 to the back of the ink container 194 increases.
[0197]
Since the ink is discharged from the ink supply port 187 and air enters from the air introduction port 185, the ink is consumed from the storage chamber 213 on the ink supply port 187 side to the storage chamber 213 at the back of the ink cartridge 180G. For example, while the ink in the storage chamber 213 closest to the ink supply port 187 is consumed and the ink level in the storage chamber 213 closest to the ink supply port 187 is lowered, the other storage chamber 213 is filled with ink. ing. When the ink in the storage chamber 213 closest to the ink supply port 187 is consumed, air enters the second storage chamber 213 counted from the ink supply port 187 and the ink in the second storage chamber 213 is consumed. For the first time, the ink level in the second storage chamber 213 begins to drop. At this time, the third and subsequent storage chambers 213 counted from the ink supply chamber 187 are filled with ink. In this way, ink is consumed in order from the storage chamber 213 close to the ink supply port 187 to the storage chamber 213 far away.
[0198]
As described above, since the actuator 106 is arranged at an interval on the upper surface 194c of the ink container 194 for each of the storage chambers 213, the actuator 106 can detect a decrease in the ink amount in stages. Further, since the capacity of the storage chamber 213 gradually decreases from the ink supply port 187 to the back of the storage chamber 213, the time interval at which the actuator 106 detects a decrease in the ink amount gradually decreases, and the ink end The frequency can be detected higher as the value approaches.
[0199]
The ink cartridge 180H in FIG. 44B has one partition wall 212 extending downward from the upper surface 194c of the ink container 194. Since the lower end of the partition wall 212 and the bottom surface of the ink container 194 are spaced apart from each other, the bottom of the ink container 194 is in communication. The ink cartridge 180H has two storage chambers 213a and 213b divided by a partition wall 212. The bottoms of the storage chambers 213a and 213b communicate with each other. The capacity of the storage chamber 213a on the ink supply port 187 side is larger than the capacity of the storage chamber 213b at the back as viewed from the ink supply port 187. The capacity of the storage chamber 213b is preferably smaller than half of the capacity of the storage chamber 213a.
[0200]
The actuator 106 is mounted on the upper surface 194c of the storage chamber 213b. Further, the storage chamber 213b is formed with a buffer 214, which is a groove for catching air bubbles entering when the ink cartridge 180H is manufactured. In FIG. 44B, the buffer 214 is formed as a groove extending upward from the side wall 194 b of the ink container 194. Since the buffer 214 captures the bubbles that have entered the ink storage chamber 213b, the malfunction that the actuator 106 detects as the ink end due to the bubbles can be prevented. Further, by providing the actuator 106 on the upper surface 194c of the storage chamber 213b, the ink amount in the storage chamber 213a grasped by the dot counter can be determined with respect to the ink amount from the detection of the ink near end to the complete ink end state. By applying correction corresponding to the consumption state, ink can be consumed to the end. Furthermore, by adjusting the capacity of the storage chamber 213b by changing the length or interval of the partition wall 212, the amount of ink that can be consumed after ink near-end detection can be changed.
[0201]
44C, the porous member 216 is filled in the storage chamber 213b of the ink cartridge 180I of FIG. 44B. The porous member 216 is installed so as to fill the entire space from the upper surface to the lower surface in the accommodation chamber 213b. The porous member 216 is in contact with the actuator 106. When the ink container falls down or during reciprocation on the carriage, air may enter the ink storage chamber 213b, which may cause the actuator 106 to malfunction. However, if the porous member 216 is provided, air can be trapped and air can be prevented from entering the actuator 106. In addition, since the porous member 216 holds ink, the ink container is shaken, so that it is possible to prevent the ink from being applied to the actuator 106 and causing the actuator 106 to erroneously detect that there is no ink. The porous member 216 is preferably installed in the storage chamber 213 having the smallest capacity. Further, by providing the actuator 106 on the upper surface 194c of the storage material 213b, it is possible to correct the ink amount from the detection of the ink near end to the complete ink end state, and to consume the ink to the end. Furthermore, by adjusting the capacity of the storage chamber 213b by changing the length or interval of the partition wall 212, the amount of ink that can be consumed after ink near-end detection can be changed.
[0202]
FIG. 44D shows an ink cartridge 180J in which the porous member 216 of the ink cartridge 180I of FIG. 44C is composed of two types of porous members 216A and 216B having different hole diameters. The porous member 216A is disposed above the porous member 216B. The hole diameter of the upper porous member 216A is larger than the hole diameter of the lower porous member 216B. Alternatively, the porous member 216A is formed of a member having a lower liquid affinity than the porous member 216B. Since the porous member 216B having a smaller pore diameter has a larger capillary force than the porous member 216A having a larger pore diameter, the ink in the storage chamber 213b is collected and held in the lower porous chamber member 216B. Therefore, once the air reaches the actuator 106 and the absence of ink is detected, the ink reaches the actuator again and does not detect the presence of ink. Further, the ink is absorbed by the porous member 216B on the side far from the actuator 106, so that the ink in the vicinity of the actuator 106 is improved, and the amount of change in the acoustic impedance change when detecting the presence or absence of ink increases. Further, by providing the actuator 106 on the upper surface 194c of the storage material 213b, it is possible to correct the ink amount from the detection of the ink near end to the complete ink end state, and to consume the ink to the end. Furthermore, by adjusting the capacity of the storage chamber 213b by changing the length or interval of the partition wall 212, the amount of ink that can be consumed after ink near-end detection can be changed.
[0203]
FIG. 45 is a cross-sectional view showing an ink cartridge 180K, which is another embodiment of the ink cartridge 180I shown in FIG. The porous member 216 of the ink cartridge 180 shown in FIG. 45 is compressed so that the horizontal sectional area of the lower part of the porous member 216 gradually decreases toward the bottom surface of the ink container 194, and the pore diameter is small. Designed to be Ink cartridge 180K in FIG. 45A is provided with ribs on the side walls in order to compress the hole diameter on the lower side of porous member 216 to be small. Since the pore diameter at the bottom of the porous member 216 is reduced by being compressed, the ink is collected and held at the bottom of the porous member 216. Ink is absorbed by the lower portion of the porous member 216 far from the actuator 106, so that the ink in the vicinity of the actuator 106 is improved, and the amount of change in the acoustic impedance change when detecting the presence or absence of ink increases. Therefore, the ink is applied to the actuator 106 mounted on the upper surface of the ink cartridge 180K due to the shaking of the ink, and the actuator 106 can be prevented from erroneously detecting that no ink is present.
[0204]
On the other hand, in the ink cartridge 180L of FIGS. 45B and 45C, the horizontal cross-sectional area of the lower portion of the porous member 216 gradually increases toward the bottom surface of the ink container 194 in the width direction of the ink container 194. In order to compress the ink container so as to be smaller, the horizontal sectional area of the storage chamber gradually decreases toward the bottom surface of the ink container 194. Since the pore diameter at the bottom of the porous member 216 is reduced by being compressed, the ink is collected and held at the bottom of the porous member 216. Ink is absorbed in the lower portion of the porous member 216B far from the actuator 106, so that ink near the actuator 106 is improved, and the amount of change in acoustic impedance change when detecting the presence or absence of ink increases. Therefore, when the ink shakes, ink is applied to the actuator 106 mounted on the upper surface of the ink cartridge 180L, and the actuator 106 can be prevented from erroneously detecting that no ink is present.
[0205]
FIG. 46 shows still another embodiment of the ink cartridge using the actuator 106. The ink cartridge 220A shown in FIG. 46A includes a first partition 222 provided so as to extend downward from the upper surface of the ink cartridge 220A. Since a predetermined gap is provided between the lower end of the first partition 222 and the bottom surface of the ink cartridge 220A, ink can flow into the ink supply port 230 through the bottom surface of the ink cartridge 220A. A second partition 224 is formed on the ink supply port 230 side from the first partition 222 so as to extend upward from the bottom surface of the ink cartridge 220A. Since a predetermined gap is provided between the upper end of the second partition 224 and the upper surface of the ink cartridge 220A, ink can flow into the ink supply port 230 through the upper surface of the ink cartridge 220A.
[0206]
A first storage chamber 225 a is formed in the back of the first partition 222 when viewed from the ink supply port 230 by the first partition 222. On the other hand, the second partition 224 forms a second storage chamber 225 b on the front side of the second partition 224 when viewed from the ink supply port 230. The capacity of the first storage chamber 225a is larger than the capacity of the second storage chamber 225b. Capillary passages 227 are formed by providing a gap between the first partition 222 and the second partition 224 to allow capillary action. Therefore, the ink in the first storage chamber 225 a is collected in the capillary passage 227 by the capillary force of the capillary passage 227. Therefore, it is possible to prevent gas or bubbles from entering the second storage chamber 225b. Further, the water level of the ink in the second storage chamber 225b can be gradually and stably lowered. Since the first storage chamber 225a is formed behind the second storage chamber 225b when viewed from the ink supply port 230, after the ink in the first storage chamber 225a is consumed, the second storage chamber 225b of ink is consumed.
[0207]
The actuator 106 is attached to the side wall of the ink cartridge 220A on the ink supply port 230 side, that is, the side wall of the second storage chamber 225b on the ink supply port 230 side. The actuator 106 detects the ink consumption state in the second storage chamber 225b. By mounting the actuator 106 on the side wall of the second storage chamber 225b, it is possible to stably detect the remaining amount of ink at a point closer to the ink end. Furthermore, by changing the height at which the actuator 106 is mounted on the side wall of the second storage chamber 225b, it is possible to freely set at which point the remaining amount of ink is used as the ink end. Since the ink is supplied from the first storage chamber 225a to the second storage chamber 225b by the capillary passage 227, the actuator 106 is not affected by the roll of the ink due to the roll of the ink cartridge 220A. Can reliably measure the remaining amount of ink. Furthermore, since the capillary passage 227 holds the ink, the ink is prevented from flowing back from the second storage chamber 225b to the first storage chamber 225a.
[0208]
A check valve 228 is provided on the upper surface of the ink cartridge 220A. The check valve 228 can prevent ink from leaking outside the ink cartridge 220A when the ink cartridge 220A rolls. Further, by installing the check valve 228 on the upper surface of the ink cartridge 220A, it is possible to prevent ink from evaporating from the ink cartridge 220A. When the ink in the ink cartridge 220A is consumed and the negative pressure in the ink cartridge 220A exceeds the pressure of the check valve 228, the check valve 228 is opened, air is sucked into the ink cartridge 220A, and then the ink is closed and the ink is closed. The pressure in the cartridge 220A is kept constant.
[0209]
46 (C) and 46 (D) show a detailed cross section of the check valve 228. The check valve 228 in FIG. 46C includes a valve 232 having a blade 232a formed of rubber. A ventilation hole 233 for the outside of the ink cartridge 220 is provided in the ink cartridge 220 so as to face the blade 232a. The air hole 233 is opened and closed by the blade 232a. When the ink in the ink cartridge 220 decreases and the negative pressure in the ink cartridge 220 exceeds the pressure of the check valve 228, the check valve 228 opens the blade 232 a to the inside of the ink cartridge 220 and removes external air. The ink cartridge 220 is taken in. The check valve 228 shown in FIG. 46D includes a valve 232 and a spring 235 made of rubber. When the negative pressure in the ink cartridge 220 exceeds the pressure of the check valve 228, the check valve 228 opens the spring 235 by pressing the spring 235, and sucks outside air into the ink cartridge 220 and then closes. Thus, the negative pressure in the ink cartridge 220 is kept constant.
[0210]
In the ink cartridge 220B of FIG. 46B, a porous member 242 is disposed in the first storage chamber 225a instead of providing the check valve 228 in the ink cartridge 220A of FIG. 46A. The porous member 242 holds the ink in the ink cartridge 220B and prevents the ink from leaking out of the ink cartridge 220B when the ink cartridge 220B rolls.
[0211]
As described above, the ink cartridge mounted on the carriage is separated from the carriage, and the ink cartridge or the actuator 106 is mounted on the carriage. However, the ink is integrated with the carriage and mounted on the inkjet recording apparatus together with the carriage. The actuator 106 may be attached to the tank. Further, the actuator 106 may be mounted on an off-carriage type ink tank that supplies ink to the carriage via a tube or the like that is separate from the carriage. Furthermore, the actuator of the present invention may be attached to an ink cartridge that is configured so that the recording head and the ink container are integrated and replaceable.
[0212]
"Ink detection technology using multiple liquid sensors"
In the foregoing, various ink cartridges that detect ink consumption using liquid sensors (elastic wave generating means and actuators) have been described. Among these, as shown in FIG. 10, for example, a configuration in which a plurality of liquid sensors are provided in an ink cartridge is shown. In the present embodiment, ink consumption is more appropriately detected using the plurality of liquid sensors.
[0213]
FIG. 47 shows a control system of the ink jet recording apparatus according to the present embodiment. Three liquid sensors 802, 804, and 806 are installed on the container wall of the ink cartridge 800. Each liquid sensor has a piezoelectric element and corresponds to the above-described actuator or elastic wave generating means. The three liquid sensors 802 to 806 are at different positions along the direction of liquid level change due to ink consumption (typically the liquid level lowering direction, and the liquid level lowering direction is mainly assumed in the present embodiment). is set up. These liquid sensors are controlled by the measurement processing unit 812 of the recording apparatus control unit 810. The recording device control unit 810 further includes a presentation processing unit 814, a printing operation control unit 816, an ink replenishment processing unit 818, a cartridge replacement processing unit 820, and a print data storage processing unit 822. These configurations will be described later.
[0214]
When a driving voltage is applied to each of the liquid sensors 802 to 806 under the control of the measurement processing unit 812, the liquid sensor vibrates. In one method described above, a change in acoustic impedance accompanying ink consumption is used. Residual vibration after the liquid sensor is driven is detected. In another method, the liquid sensor generates an elastic wave by vibration and then outputs a signal corresponding to the reflected wave with respect to the elastic wave. The time until the reflected wave returns may be detected. Other methods using a piezoelectric element may be applied.
[0215]
Since the acoustic impedance varies greatly depending on whether the liquid level is higher than the sensor, the detection signal of the liquid sensor is different. The measurement processing unit 812 can determine whether the ink level has passed through each sensor based on the detection signal. The detection process is periodically performed at a predetermined timing.
[0216]
Here, a state in which the liquid level is lower than the sensor is referred to as “ink empty state”, and a state in which the liquid level is higher than the sensor is referred to as “ink present state”. When the liquid level passes through the sensor, the detection result changes from “ink present state” to “ink empty state”. In the present embodiment, the detection of passing through the liquid level indicates a change in the detection result.
[0217]
As a feature of the present embodiment, the measurement processing unit 812 switches the detection position of the sensor along the ink liquid level decreasing direction according to the progress of ink consumption. Immediately after mounting the cartridge, that is, in the ink full state, only the liquid sensor 802 is used. When ink is consumed and the liquid level passes through the sensor 802, the liquid sensor 802 detects an ink empty state. In response to this, the measurement processing unit 812 switches the ink detection position to the middle stage. That is, ink consumption is detected using only the liquid sensor 804. Similarly, when the liquid sensor 804 detects an ink empty state, the detection position is switched to the lowest level (liquid sensor 806).
[0218]
According to the present embodiment, since the detection position is sequentially switched downward, all the liquid sensors need not always operate, and the operation of the liquid sensors is reduced. Thereby, the data processing amount in the measurement processing unit 812 can also be reduced.
[0219]
Further, in the present embodiment, the detection frequency is increased according to the change in the ink liquid level. The detection frequency is preferably increased when the detection position is shifted downward. That is, the detection processing interval is changed to be shorter. Thereby, as described below, the number of detections as a whole can be reduced.
[0220]
For example, when the ink level is higher than that of the liquid sensor 802, the amount of ink is sufficiently large, so that there is little need to find the liquid level passing through the sensor early. Therefore, the detection frequency is set to be relatively low until the liquid sensor 802 detects the ink empty state. On the other hand, after the ink level has passed through the liquid sensor 804, it is the liquid sensor 806 that detects the passage of the ink level next. The liquid sensor 806 is located at the bottom, and detects an ink near end (a state in which ink is almost completely consumed). The liquid sensor 806 preferably detects the passage of the liquid level early. Therefore, the detection frequency of the liquid sensor 806 is set larger than that of the liquid sensor 802. By such control, the detection frequency when it is desired to detect ink consumption early can be increased, and the detection frequency in other states can be decreased. It is possible to reduce the number of times of detection processing as a whole while ensuring acquisition of necessary information.
[0221]
The advantage of this embodiment is significant compared to the case where there is only one liquid sensor. Suppose that only the liquid sensor 806 for detecting the ink near end is provided. In this case, the liquid sensor 806 must always repeat the detection process at a high frequency in order to quickly detect the arrival of the liquid level. On the other hand, according to the present embodiment, when the ink consumption is not progressing, the ink consumption may be detected at a relatively low frequency using the liquid sensor 802 or the liquid sensor 804. Therefore, the number of times the liquid sensor operates can be greatly reduced.
[0222]
As described above, according to the present embodiment, it is possible to capture the ink consumption state efficiently and accurately with relatively few detection operations. The burden of processing by the measurement processing unit 812 is reduced. This is also advantageous for other configurations of the printing apparatus control unit 810. For example, considering the case where printing is continued at a high speed for a long time in a large recording apparatus, the number of times the measurement process is performed during the printing process can be reduced.
[0223]
In the present embodiment, it is not always necessary to change the detection frequency every time the detection position is switched. For example, the liquid sensor 802 and the liquid sensor 804 in FIG. 47 may detect ink consumption at the same frequency. Alternatively, the detection frequencies of the liquid sensor 804 and the liquid sensor 806 may be the same.
[0224]
In the present embodiment, the number of liquid sensors is three. However, the number of liquid sensors is not limited as long as it is two or more. Further, the interval between the liquid sensors may not be constant. For example, it is preferable to narrow the interval between the liquid sensors as the liquid level becomes lower. Such a modification can be similarly applied to other embodiments described below.
[0225]
"Control of inkjet printing device based on ink consumption"
Returning to FIG. 47, the recording apparatus control unit 810 further includes a presentation processing unit 814, a printing operation control unit 816, an ink supplement processing unit 818, a cartridge replacement processing unit 820, and a print data storage processing unit 822. These configurations control the ink jet recording apparatus based on the ink consumption state detected by the measurement processing unit 812. In the present embodiment, the liquid level position is detected in stages by detecting impedance changes at a plurality of detection positions. A plurality of liquid level positions that cannot be obtained with a single sensor are obtained. Since this liquid surface position information is used, the recording apparatus can also be suitably controlled. The recording device control unit 810 may be provided inside the ink jet recording device or may be provided outside. A part or all of the functions of the control unit 810 may be given to an external device such as a computer connected to the recording device.
[0226]
The presentation processing unit 814 presents information corresponding to the liquid sensor that has detected passage of the liquid level. A display 830 and a speaker 832 are used for presenting information. The display 830 is a display panel of a recording device, for example. The display 830 may be a screen of a computer connected to the recording device. Preferably, the display form is changed according to the liquid sensor that detects passage of the liquid level.
[0227]
FIG. 48 shows an example of processing for changing the display form. When the liquid sensor 802 at the highest position detects passage of the liquid level, a blue long bar figure is displayed. A similar figure may be displayed before detection by the liquid sensor 802. Next, when the liquid sensor 804 at the middle stage detects the passage of the liquid level, a yellow bar figure having a medium length is displayed. Further, when the lowermost liquid sensor 806 detects passage of the liquid level, a red short bar figure is displayed. The display may be in the form of using LEDs or the like directly. By changing the display form, in detail, by changing the color and graphic, the user can easily inform the user of the ink consumption state.
[0228]
In addition, the presentation processing unit 814 presents information using the speaker 832. When the liquid sensor detects the passage of the liquid level, a notification sound is output from the speaker 832. The speaker 832 may be a speaker of a recording device or a speaker of an external device such as a computer connected to the recording device. Preferably, also in this case, the notification sound is varied according to the liquid sensor. It is also preferable to use an audio signal as the notification sound. A synthesized voice indicating the ink consumption state is generated by the voice synthesis process. At this time, the content of the message is changed according to the amount of ink, that is, according to the liquid sensor that has detected passage of the liquid level.
[0229]
Other configurations (816, 818,...) Of the recording apparatus control unit 810 respond to the liquid sensor (FIG. 47, 806) attached to the lowest position of the ink cartridge detecting the passage of the liquid level. A predetermined low ink amount handling process is performed. The low ink amount handling process is a process for prohibiting or suppressing the operation of the recording apparatus such as improper printing in consideration of the fact that the remaining ink is low.
[0230]
The printing operation control unit 816 controls the printing apparatus 834 to stop the printing operation as the low ink handling process. Thereby, the printing operation after the ink runs out is avoided.
[0231]
The printing operation control unit 816 may prohibit the printing maintenance operation (cleaning operation) as the low ink handling process. In this embodiment, the print head is included in the print maintenance target. During the maintenance of the print head, a relatively large amount of ink is sucked from the head. According to this embodiment, it is possible to avoid the remaining little ink from being sucked from the head for maintenance, and it is also possible to avoid a situation where the ink is insufficient for maintenance.
[0232]
In addition, as another example of the low ink amount handling process, the printing operation control unit 816 may prohibit a certain printing process from moving to the next printing process. Thereby, it is possible to avoid the printing from stopping during one printing process, for example, printing a series of sentences.
[0233]
The ink replenishment processing unit 818 automatically replenishes ink in the ink cartridge by controlling the ink replenishing device 836 as the low ink amount handling process. Thereby, printing can be continued.
[0234]
The cartridge replacement processing unit 820 controls the cartridge replacement device 838 to automatically replace the ink cartridge as the low ink amount handling process. The printing operation can be continued by this handling process.
[0235]
The print data storage processing unit 822 stores the print data before completion of printing in the print data storage unit 840 as the low ink amount handling process. Thereby, it is possible to avoid the loss of print data before printing.
[0236]
All of these configurations 814 to 822 may not be provided in the recording apparatus control unit 810. It is sufficient that at least one low ink amount handling process is performed. For example, if the ink replenishment processing unit 818 or the cartridge replacement processing unit 820 is provided, the printing operation control unit 816 may not perform the printing operation stop process. In addition, a configuration for performing processing corresponding to a low ink amount other than those exemplified above, and a configuration for avoiding an inappropriate operation due to ink shortage may be provided.
[0237]
Further, it is preferable that the low ink amount handling process is executed after the “predetermined margin amount” is printed after the liquid sensor at the lowest position detects passage of the liquid level. The “predetermined margin” is set to an appropriate value that is smaller than the printing amount that consumes all ink after the liquid level is detected by the liquid sensor.
[0238]
Referring to FIG. 47, the liquid sensor 806 detects the ink near end state. Even after detection by the liquid sensor 806, a small amount of ink remains. According to this aspect, it is possible to execute the low ink amount handling process after further consuming ink, that is, using up as much ink as possible.
[0239]
The “predetermined margin” may be defined by the number of printed sheets. For example, the number of prints from when the bottom liquid sensor detects the passage of the liquid level until the execution of the low ink amount handling process is preset. According to this aspect, it is possible to avoid performing the low ink amount handling process in the middle of printing a certain page. Stopping printing in the middle of printing a certain page or starting cartridge replacement processing in the middle of printing is avoided. Therefore, the low ink amount handling process can be performed at an appropriate timing.
[0240]
"Liquid level grasp by scanning of sensor"
FIG. 49 shows a recording apparatus control system according to another embodiment of the present invention. The ink cartridge 900 has a vertically long shape, and is a so-called fixed ink cartridge for off-carriage, for example. The ink cartridge 900 has seven liquid sensors 902 to 914 along the liquid level lowering direction due to ink consumption. The liquid sensors 902 to 914 are controlled by the measurement processing unit 812 of the recording device control unit 810. The operation of each liquid sensor is substantially the same as that of the embodiment of FIG. The measurement processing unit 812 obtains a back electromotive voltage output from each sensor while giving a driving voltage to each liquid sensor.
[0241]
The measurement processing unit 812 periodically detects the ink surface level at a predetermined measurement interval. The liquid sensors 902 to 914 are used for each detection process. For example, the liquid sensors sequentially operate from the uppermost liquid sensor 902 to the lowermost liquid sensor 914 (liquid sensor scanning operation). Assume that the liquid level is between the liquid sensor 910 and the liquid sensor 912. In this case, the liquid sensors 902 to 910 detect an ink empty state. On the other hand, the liquid sensor 912 and the liquid sensor 914 detect the presence of ink. Therefore, the liquid level position can be accurately determined. Note that the scanning direction of the liquid sensor may be reversed.
[0242]
The measurement processing unit 812 may not use the liquid sensor at the detection position where the liquid level has already passed. For example, in the example of FIG. 49, since the liquid sensors 902 to 910 are already in positions where the liquid level has passed, they may not be used for the detection process. Here, the liquid sensor that has detected the ink empty state for a predetermined number of times may be excluded from the detection processing target. As a result, the liquid sensor that is surely above the liquid level can be removed from the detection processing target.
[0243]
The measurement processing unit 812 preferably increases the detection frequency when the number of liquid sensors not used in the detection process increases. An increase in the number of liquid sensors that are not used for the detection process means that the liquid level has decreased. When the liquid level is lowered and the amount of ink is reduced, ink consumption can be detected early due to an increase in the detection frequency. Since the number of sensors is reduced, there is little increase in the burden on the measurement processing unit. Therefore, according to this embodiment, it is possible to detect ink consumption earlier when the amount of ink is reduced while suppressing an increase in the burden of detection processing.
[0244]
In a preferred embodiment, the scanning direction of the liquid sensor is switched while the ink consumption is progressing. FIG. 50 shows a scan direction switching process. A predetermined detection direction switching level 920 (scan direction switching level) is preset. In this example, the switching level 920 matches the height of the liquid sensor 908. The liquid sensor 908 is approximately at the center of the ink cartridge. When the liquid level is above the switching level 920, the scan direction is downward. Accordingly, the liquid sensor 902 operates first, then the liquid sensor 904 operates, and the lower sensor sequentially operates. On the other hand, when ink consumption progresses and the liquid level falls below the switching level 920, that is, when the liquid sensor 908 detects an ink empty state, the scanning direction of the liquid sensor is switched upward. First, the liquid sensor 914 operates, then the liquid sensor 912 operates, and the upper sensor sequentially operates.
[0245]
Here, when the liquid level is high, it is possible to find the liquid level earlier by searching for the liquid level from the top to the bottom. Conversely, when the liquid level is low, searching for the liquid level from the bottom to the top can find the liquid level more quickly. Therefore, according to this embodiment, the liquid level position can be grasped efficiently.
[0246]
Further, in this embodiment, if the liquid level position can be grasped, the liquid detection may be ended even before the detection at all the planned detection positions is ended. For example, on the left side of FIG. 50, when the liquid sensor 906 detects the ink presence state, the liquid level position is known, so the detection process may be terminated.
[0247]
As is clear from the above description, according to the present embodiment, the position of the liquid level can be found quickly and efficiently, and the operation of the useless liquid sensor can be reduced.
[0248]
Note that the switching level 920 need not be at the center of the cartridge. Further, the switching level 920 may not be the same position as the center sensor.
[0249]
`` Restrict sensor usage during printing ''
Preferably, the measurement control process is changed depending on whether or not the ink jet recording apparatus is performing a printing operation. During the printing operation, the number of liquid sensors used for detection is limited. This is a process of using a smaller number of liquid sensors than usual in order to obtain information limited to the extent that the printing apparatus control based on the detection result is possible.
[0250]
Preferably, only the lowest liquid sensor (FIGS. 49, 914) is used during the printing operation. Using this lowermost liquid sensor, it is determined only whether or not the remaining ink is low. If not in a printing operation, other liquid sensors are also used according to the process described above.
[0251]
The advantages of this form will be described. During the printing operation, it is desirable to reduce the burden of the ink consumption detection process as much as possible. For example, the recording device control unit 810 in FIG. 49 controls detection processing and printing operation. The detection process may affect the printing operation. It is considered that the printing process proceeds more quickly when the detection process is simpler. According to this embodiment, since the operation of the liquid sensor is limited within a range where useful information can be obtained, the burden of detection processing during the printing operation can be reduced.
[0252]
Various modifications can be made to the form of restriction of the sensor operation. For example, the liquid sensor is appropriately thinned out. Only odd or even liquid sensors may be used. Also, only the top, middle and bottom liquid sensors may be used. Further, only the liquid sensor that is expected to detect the passage of the liquid level next may be used. In the example of FIG. 49, only the liquid sensor 912 is used during the printing operation.
[0253]
"Fail measures"
Further, in the present embodiment, the following processing is performed as a countermeasure against printer failure. FIG. 51 shows the failure countermeasure of this embodiment. In the figure, white circles indicate that the liquid sensor has detected an ink empty state. A black circle indicates that the liquid sensor has detected an ink presence state. As shown in the drawing, the upper three liquid sensors 902 to 906 detect the ink empty state. The fourth liquid sensor 908 detects the presence of ink. However, the fifth liquid sensor 910 detects an ink empty state. Further, the two lower liquid sensors 912 and 914 detect the presence of ink.
[0254]
At this time, it is considered that a failure has occurred in the liquid sensor 908 or the liquid sensor 910. However, it cannot be determined which liquid sensor has failed. Therefore, in this embodiment, it is determined that the liquid level is between the liquid sensor 910 and the liquid sensor 912. This means that when there is a possibility of failure in a plurality of liquid sensors, it is determined that the upper liquid sensor has failed. Due to such determination, the liquid level is estimated to be low, so that adverse effects due to erroneous determination can be minimized.
[0255]
As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.
[0256]
For example, in the present embodiment, the present invention is applied to an ink cartridge. On the other hand, the present invention is not limited to the ink cartridge, but may be applied to other ink tanks or ink containers, or may be applied to containers that contain liquids other than ink.
[0257]
In the above embodiment, the liquid sensor generates vibration and generates a detection signal indicating the ink consumption state. In one method, after the occurrence of vibration, a signal indicating a residual vibration state is output. In another method, after generating an elastic wave due to vibration, a signal corresponding to the reflected wave was output. On the other hand, the liquid sensor may not generate vibrations by itself. That is, both vibration generation and detection signal output may not be performed. Vibration is generated by another actuator. Alternatively, the liquid sensor may generate a detection signal indicating the ink consumption state when vibration occurs in the ink cartridge as the carriage moves. Ink consumption is detected using vibrations that are naturally generated by printer operation without actively generating vibrations.
[0258]
【The invention's effect】
As will be apparent from the above description, according to the present invention, the liquid consumption state in the liquid container is detected based on vibration using the piezoelectric element. The liquid consumption state can be appropriately captured by switching the detection position. Furthermore, the ink jet recording apparatus can be appropriately controlled based on the liquid consumption state.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an embodiment of an ink cartridge for a single color, for example, black ink.
FIG. 2 is a diagram illustrating an embodiment of an ink cartridge that stores a plurality of types of ink.
3 is a diagram showing an embodiment of an ink jet recording apparatus suitable for the ink cartridge shown in FIGS. 1 and 2. FIG.
4 is a diagram showing a detailed cross section of a sub tank unit 33. FIG.
FIG. 5 is a diagram showing a method of manufacturing the elastic wave generating means 3, 15, 16, and 17.
6 is a diagram showing another embodiment of the elastic wave generating means 3 shown in FIG.
FIG. 7 is a view showing another embodiment of the ink cartridge of the present invention.
FIG. 8 is a view showing still another embodiment of the ink cartridge of the present invention.
FIG. 9 is a view showing still another embodiment of the ink cartridge of the present invention.
FIG. 10 is a view showing still another embodiment of the ink cartridge of the present invention.
FIG. 11 is a view showing still another embodiment of the ink cartridge of the present invention.
12 is a view showing another embodiment of the ink cartridge shown in FIG. 11. FIG.
FIG. 13 is a view showing still another embodiment of the ink cartridge of the present invention.
FIG. 14 is a view showing a plane of still another embodiment of the through hole 1c.
FIG. 15 is a view showing a cross section of an embodiment of the ink jet recording apparatus of the present invention.
16 is a diagram showing an embodiment of an ink cartridge suitable for the recording apparatus shown in FIG.
17 is a view showing another embodiment of the ink cartridge 272 of the present invention. FIG.
FIG. 18 is a view showing still another embodiment of the ink cartridge 272 and the ink jet recording apparatus of the present invention.
FIG. 19 is a view showing another embodiment of the ink cartridge 272 shown in FIG.
20 is a diagram showing details of the actuator 106. FIG.
FIG. 21 is a diagram showing the periphery of an actuator and its equivalent circuit.
FIG. 22 is a diagram illustrating a relationship between ink density and ink resonance frequency detected by an actuator.
23 is a diagram showing a back electromotive force waveform of the actuator 106. FIG.
24 is a diagram showing another embodiment of the actuator 106. FIG.
FIG. 25 is a view showing a cross section of a part of the actuator shown in FIG. 24;
26 is a diagram showing an overall cross section of the actuator 106 shown in FIG. 26;
27 is a diagram showing a method of manufacturing the actuator 106 shown in FIG. 24. FIG.
FIG. 28 is a view showing still another embodiment of the ink cartridge of the present invention.
FIG. 29 is a diagram showing another embodiment of the through hole 1c.
30 is a view showing another embodiment of the actuator 660. FIG.
31 is a view showing still another embodiment of the actuator 670. FIG.
32 is a perspective view showing the module body 100. FIG.
33 is an exploded view showing a configuration of the module body 100 shown in FIG. 32. FIG.
FIG. 34 is a diagram showing another embodiment of the module body 100. FIG.
35 is an exploded view showing a configuration of the module body 100 shown in FIG. 34. FIG.
36 is a view showing still another embodiment of the module body 100. FIG.
37 is a diagram showing an example of a cross section in which the module body 100 shown in FIG. 32 is mounted on the ink container 1. FIG.
38 is a view showing still another embodiment of the module body 100. FIG.
39 is a diagram showing an embodiment of an ink cartridge and an ink jet recording apparatus using the actuator 106 shown in FIGS. 20 and 21. FIG.
FIG. 40 is a diagram illustrating details of the ink jet recording apparatus.
41 is a view showing another embodiment of the ink cartridge 180 shown in FIG. 40. FIG.
42 is a view showing still another embodiment of the ink cartridge 180. FIG.
43 is a view showing still another embodiment of the ink cartridge 180. FIG.
44 is a view showing still another embodiment of the ink cartridge 180. FIG.
45 is a view showing another embodiment of the ink cartridge 180 shown in FIG. 44 (C). FIG.
46 is a view showing still another embodiment of the ink cartridge using the module body 100. FIG.
FIG. 47 is a diagram showing a control system of the ink jet recording apparatus according to the present embodiment.
FIG. 48 is a diagram illustrating an example of processing for changing a display form when displaying an ink consumption state;
FIG. 49 is a diagram showing another control system of the ink jet recording apparatus according to the present embodiment.
FIG. 50 is a diagram showing a process of switching the detection direction of the liquid surface position in the ink consumption process in the system of FIG. 48.
51 is a diagram showing a sensor failure countermeasure process in the system of FIG. 48. FIG.
[Explanation of symbols]
800 ink cartridge
802-806 Liquid sensor
810 Recording device controller
812 Measurement processing unit
814 Presentation processing unit
816 Printing operation control unit
818 Ink replenishment processing unit
820 Cartridge replacement processing unit
822 Print data storage processing unit
900 Ink cartridge
902-914 Liquid sensor

Claims (27)

A liquid consumption detection method for detecting a consumption state of a liquid in a liquid container based on vibration using a piezoelectric element,
A plurality of liquid sensors each having a piezoelectric element are provided at a plurality of detection positions along the liquid level change direction of the liquid,
When the liquid level is higher than a predetermined detection direction switching level, using the plurality of liquid sensors in order from the high detection position toward the low detection position,
When the liquid level is lower than the predetermined detection direction switching level, using the plurality of liquid sensors in order from the low detection position toward the high detection position,
A method for detecting liquid consumption, comprising detecting a change in liquid level due to consumption of the liquid.   The liquid consumption detection method according to claim 1, wherein the detection frequency is increased in accordance with the change in the liquid level.   3. The liquid sensor used for liquid detection is switched to one in the liquid level change direction when a liquid sensor of the plurality of liquid sensors detects passage of the liquid level. 4. Liquid consumption detection method. A liquid consumption detection method for detecting a consumption state of a liquid in a liquid container based on vibration using a piezoelectric element,
A plurality of liquid sensors each having a piezoelectric element are provided at a plurality of detection positions along the liquid level change direction of the liquid,
When the liquid level is higher than a predetermined detection direction switching level, using the plurality of liquid sensors in order from the high detection position toward the low detection position,
When the liquid level is lower than the predetermined detection direction switching level, using the plurality of liquid sensors in order from the low detection position to the high detection position,
A liquid consumption detection method characterized by grasping a liquid surface position by detecting passage of the liquid surface at a plurality of detection positions at each liquid detection.   The liquid consumption detection method according to claim 4, wherein a liquid level position is obtained using a plurality of liquid sensors provided corresponding to the plurality of detection positions, each having a piezoelectric element.   6. The liquid consumption detection method according to claim 5, wherein the liquid level position is obtained without using a liquid sensor at a detection position where the liquid level has already passed.   The liquid consumption detection method according to claim 6, wherein when the number of liquid sensors used for detection decreases, the detection frequency is increased.   The liquid consumption detection method according to claim 1, wherein once the liquid level position is grasped, the liquid detection at that time is ended even before the detection at all planned detection positions is ended.   The liquid consumption detection method according to claim 1, wherein a liquid consumption state is detected by the liquid sensor based on a change in acoustic impedance.   The liquid consumption state according to claim 9, wherein the liquid sensor outputs a signal indicating a residual vibration state, and the liquid consumption state is detected based on the residual vibration state changing according to the liquid consumption state. Detection method.   The liquid consumption detection method according to claim 1, wherein ink consumption of an ink cartridge which is a liquid container mounted on the ink jet recording apparatus is detected.   The liquid consumption detection method according to claim 11, wherein the number of liquid sensors used for liquid detection is limited during a printing operation by the ink jet recording apparatus.   The liquid consumption detection method according to claim 12, wherein the lowermost liquid sensor is used during a printing operation by the ink jet recording apparatus, and a plurality of liquid sensors are used when the printing operation is not being performed. A recording apparatus control method for controlling an inkjet recording apparatus based on an ink consumption state of an ink container,
A plurality of liquid sensors each having a piezoelectric element are provided at a plurality of detection positions set along the liquid level lowering direction of the ink,
When the liquid level is higher than a predetermined detection direction switching level, using the plurality of liquid sensors in order from the high detection position toward the low detection position,
When the liquid level is lower than the predetermined detection direction switching level, using the plurality of liquid sensors in order from the low detection position toward the high detection position,
Detecting the liquid surface position by detecting passage of the liquid surface based on vibration using the piezoelectric element,
A recording apparatus control method, comprising: controlling the ink jet recording apparatus in accordance with a detected liquid level position.   The recording apparatus control method according to claim 14, wherein a liquid surface position is obtained using a plurality of liquid sensors provided corresponding to the plurality of detection positions, each having a piezoelectric element.   The recording apparatus control method according to claim 15, wherein information corresponding to the liquid sensor that has detected passage of the liquid level is presented.   16. The recording apparatus control method according to claim 15, wherein information corresponding to a liquid sensor that detects passage of the liquid level is displayed on the inkjet recording apparatus or outside thereof.   The recording apparatus control method according to claim 17, wherein the display form is changed according to the liquid sensor that detects passage of the liquid level.   The recording apparatus control method according to claim 15, wherein predetermined low ink amount handling processing is performed in response to detection of passage of a liquid level by a liquid sensor provided at a lowest position.   The recording apparatus control method according to claim 19, wherein the predetermined low ink amount handling process is at least one of stopping a printing operation or prohibiting a printing maintenance operation.   20. The recording apparatus control method according to claim 19, wherein the predetermined low ink amount handling process is a process of prohibiting a transition to a next printing process after a certain printing process is completed.   The predetermined low ink amount handling process is executed after a predetermined margin amount of printing is performed after the liquid sensor provided at the lowest position detects passage of the liquid level. 21. The recording apparatus control method according to any one of 21.   23. The recording apparatus control method according to claim 15, wherein a liquid consumption state is detected by the liquid sensor based on a change in acoustic impedance.   The recording apparatus according to claim 23, wherein the liquid sensor outputs a signal indicating a residual vibration state, and the liquid consumption state is detected based on the residual vibration state changing according to the liquid consumption state. Control method. A liquid consumption detection device that detects a consumption state of a liquid in a liquid container based on vibration using a piezoelectric element,
A plurality of liquid sensors each having a piezoelectric element are provided at a plurality of detection positions along the liquid surface change direction,
When the liquid level is higher than a predetermined detection direction switching level, using the plurality of liquid sensors in order from the high detection position toward the low detection position,
When the liquid level is lower than the predetermined detection direction switching level, using the plurality of liquid sensors in order from the low detection position toward the high detection position,
A liquid consumption detecting apparatus for detecting the liquid level position. A liquid consumption detection device that detects a consumption state of a liquid in a liquid container based on vibration using a piezoelectric element,
A plurality of liquid sensors each having a piezoelectric element are provided at a plurality of detection positions along the liquid surface change direction,
When the liquid level is higher than a predetermined detection direction switching level, using the plurality of liquid sensors in order from the high detection position toward the low detection position,
When the liquid level is lower than the predetermined detection direction switching level, using the plurality of liquid sensors in order from the low detection position toward the high detection position,
A liquid consumption detection apparatus characterized by grasping a liquid surface position by detecting passage of the liquid surface at a plurality of detection positions in each liquid detection. A recording apparatus control system for controlling an inkjet recording apparatus based on an ink consumption state of an ink container,
A plurality of liquid sensors each having a piezoelectric element are provided at a plurality of detection positions along the liquid surface change direction,
When the liquid level is higher than a predetermined detection direction switching level, using the plurality of liquid sensors in order from the high detection position toward the low detection position,
When the liquid level is lower than the predetermined detection direction switching level, using the plurality of liquid sensors in order from the low detection position to the high detection position,
A recording apparatus control system, wherein a liquid surface position is detected by detecting passage of the liquid surface based on vibration using the piezoelectric element, and the ink jet recording apparatus is controlled according to the detected liquid surface.

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