JPS649739U

JPS649739U -

Info

Publication number: JPS649739U
Application number: JP10271787U
Authority: JP
Priority date: 1987-07-06
Filing date: 1987-07-06
Publication date: 1989-01-19

Description

[Brief explanation of the drawing]

第１図は本考案の機能ブロツク図である。第２
図は本考案の一実施例の概略ブロツク図である。
第３図は本考案の一実施例に適用されるドロツプ
センサならびにプリントヘツドおよびガターの概
略斜視図である。第４図は第３図に示されたガタ
ーの縦断面図である。第５図は本考案の一実施例
に適用されるドロツプセンサの拡大正面図および
フオトデイテクタ対３０Ａの出力信号特性を示す
グラフである。第６図はＬＥＤ駆動手段の詳細を
示す回路図である。第７図は出力差検出手段の詳
細を示す回路図である。第８図は各ノズルのｘ軸
方向の方向性誤差を検出する場合の本考案の一実
施例の動作を示すフローチヤートである。第９図
は第８図のステツプＳ６において検出された出力
差Ｄｉを、各ノズルにｘ軸方向の方向性誤差がな
いと仮定した場合に該各ノズルより噴出されるイ
ンク滴のｘ軸方向の飛翔位置ｘｉに対応させたグ
ラフである。第１０図は各ノズルのｚ軸方向の方
向性誤差を検出する場合の本考案の一実施例の動
作を示すフローチヤートである。第１１図は本考
案の一実施例に適用されるドロツプセンサの拡大
正面図およびフオトデイテクタ対３０Ｂの出力信
号特性を示すグラフである。第１２図は本考案の
一実施例の機能ブロツク図である。第１３図はマ
ルチノズルインクジエツトプリンタにおけるイン
ク滴飛翔の様子を示す概略図である。第１４図は
従来のドロツプセンサの概略図である。第１５図
はドロツプセンサと該ドロツプセンサを通過する
インク滴の位置座標を示す図である。第１６図は
第１５図に示されたドロツプセンサより出力され
る出力差Ｄとインク滴のｘ軸方向の飛翔位置との
関係を示すグラフである。１Ａ，１Ｂ……ＬＥＤ、６……プリントヘツド
、７，７Ａ……ドロツプセンサ、９―ｉ……ノズ
ル、３０Ａ，３０Ｂ……フオトデイテクタ対、３
１，３２，３３，３４……フオトデイテクタ、４
１……インク供給手段、４２……インク滴噴射手
段、４３……ＬＥＤ駆動手段、４４……出力差検
出手段、４５……マイクロコンピユータ、６１，
６１Ａ……制御手段、６２……Ｄｉ記憶手段、６
３……出力特性算出記憶手段、６３Ａ……出力特
性記憶手段、６４……ｘｉ記憶手段、６５……ｘ
ｉ′算出手段、６６……δｘｉ算出手段、６７…
…方向性誤差記憶手段、６８，６９……切換器、
７０……方向性誤差算出手段。 FIG. 1 is a functional block diagram of the present invention. Second
The figure is a schematic block diagram of one embodiment of the present invention.
FIG. 3 is a schematic perspective view of a drop sensor, print head, and gutter applied to one embodiment of the present invention. FIG. 4 is a longitudinal sectional view of the gutter shown in FIG. 3. FIG. 5 is an enlarged front view of a drop sensor applied to one embodiment of the present invention and a graph showing output signal characteristics of the photodetector pair 30A. FIG. 6 is a circuit diagram showing details of the LED driving means. FIG. 7 is a circuit diagram showing details of the output difference detection means. FIG. 8 is a flowchart showing the operation of an embodiment of the present invention when detecting the directional error of each nozzle in the x-axis direction. FIG. 9 shows the output difference Di detected in step S6 of FIG. 8 in the x-axis direction of the ink droplets ejected from each nozzle, assuming that each nozzle has no directional error in the x-axis direction. It is a graph made to correspond to flight position xi. FIG. 10 is a flowchart showing the operation of an embodiment of the present invention when detecting the directional error of each nozzle in the z-axis direction. FIG. 11 is an enlarged front view of a drop sensor applied to one embodiment of the present invention and a graph showing output signal characteristics of the photodetector pair 30B. FIG. 12 is a functional block diagram of an embodiment of the present invention. FIG. 13 is a schematic diagram showing how ink droplets fly in a multi-nozzle inkjet printer. FIG. 14 is a schematic diagram of a conventional drop sensor. FIG. 15 is a diagram showing a drop sensor and the position coordinates of an ink droplet passing through the drop sensor. FIG. 16 is a graph showing the relationship between the output difference D output from the drop sensor shown in FIG. 15 and the flying position of the ink droplet in the x-axis direction. 1A, 1B...LED, 6...Print head, 7,7A...Drop sensor, 9-i...Nozzle, 30A, 30B...Photodetector pair, 3
1, 32, 33, 34...photo detector, 4
1... Ink supply means, 42... Ink droplet ejection means, 43... LED driving means, 44... Output difference detection means, 45... Microcomputer, 61,
61A...control means, 62...Di storage means, 6
3...Output characteristic calculation storage means, 63A...Output characteristic storage means, 64...xi storage means, 65...x
i′ calculation means, 66...δxi calculation means, 67...
...Directional error storage means, 68, 69...Switcher,
70...Directional error calculation means.

Claims

[Scope of Claim for Utility Model Registration] (1) A flying droplet detection device for an inkjet printer equipped with a print head in which a plurality of nozzles are arranged in one direction, the flying path of ink droplets ejected from the plurality of nozzles. a drop sensor comprising: a light source arranged to illuminate the light source; and at least one pair of photodetectors arranged to face the light source; driving means for energizing the light source; connected to the pair of photodetectors; Output difference detection means for detecting a temporal integral value Di of the difference between the signals output from each photodetector; Output characteristic storage means for storing the output signal characteristics of the photodetector pair; Output from the output difference detection means directional error calculation means for detecting a directional error of a nozzle from a temporal integral value Di and an output signal characteristic stored in the output characteristic storage means; and a directional error output from the directional error calculation means. 1. A flying droplet detection device for an inkjet printer, comprising: directional error storage means for storing directional error storage means. (2) The drop sensor includes a light source arranged to perpendicularly illuminate a surface including an ideal flight path of ink droplets ejected from a plurality of nozzles, and a pair of photodetectors arranged to face the light source. The directional error calculation means uses the output signal characteristics stored in the output characteristic storage means to detect the nozzle of the ink drop corresponding to the temporal integral value Di output from the output difference detection means. xi' calculation means for calculating the actual flight position xi' in the arrangement direction; xi storage means in which the ideal flight position xi of ink droplets ejected from each nozzle in the nozzle arrangement direction is stored; and the xi' calculation. and δxi calculating means for calculating the directional error δxi of each nozzle by calculating the difference between xi' calculated by the means and xi stored in the xi storage means. A flying droplet detection device for an inkjet printer according to claim 1. (3) The drop sensor includes a light source arranged parallel to a plane including an ideal flight path of ink droplets ejected from a plurality of nozzles so as to illuminate the flight path, and a light source arranged to face the light source. The directional error calculation means corresponds to the temporal integral value Di output from the output difference detection means, using the output signal characteristics stored in the output characteristic storage means. Claim 1 of the above-mentioned utility model registration claim, characterized by comprising zi' calculation means for calculating the actual flight position zi' of the ink droplet in a direction perpendicular to the nozzle arrangement direction as a nozzle directional error δzi. The flying droplet detection device for the inkjet printer described above. (4) The output signal characteristics of the photodetector pair stored in the output characteristic storage means are based on the temporal integral value Di output from the output difference detection means and the nozzle arrangement direction of the ink droplets ejected from each nozzle. A flying droplet detection device for an inkjet printer according to claim 1 or 2, characterized in that the flying droplet detection device for an inkjet printer is approximately calculated using the ideal flying position xi. (5) The utility model registration claim characterized in that the output signal characteristics of the photodetector pair stored in the output characteristics storage means are calculated by approximating the central part of the characteristic curve as a linear function. 5. The flying droplet detection device for an inkjet printer according to item 4. (6) The utility model according to any one of claims 1 to 3, wherein the output signal characteristics of the photodetector pair stored in the output characteristics storage means are determined in advance through experiments. Flying droplet detection device for inkjet printers.