FR2475722A3 - Fast response ink jet X-Y pen recorder - has parallel lines of different coloured ink pens directed towards common point - Google Patents

Abstract

A recording device has a writer for automatically displaying curves, diagrams or images in a fixed orthogonal coordinate system. A movable writer head is arranged above the recording plane. It contains two or more pens. The construction of the writing unit is improved w.r.t. similar devices so as to yield a shorter writing head reaction line. A conventional piezoelectrically activated ink gun writing pen with a spray nozzle (3) is used. A large number of ink guns is arranged parallel to one axis (X) of the coordinate system. Guns dispensing the same colour ink are uniformly distributed along a straight line at a fixed distance (d) from the recording plane (1). Lines of different colour ink pens are arranged in parallel. The associated pens are aimed at a common point in the recording plane.

Description

The invention relates to the field of recording devices, and it is to be applied to the development relating to the construction of a writing device for the multicolored trace for a two-coordinate recording device.
In the recording of measured values by plotting measuring devices, there is interest, inter alia, in the reciprocal behavior between two measured quantities, possibly their interdependence. The corresponding measuring devices are provided with a device for writing, the writing head of which is arranged above the writing plane, is capable of being displaced in both directions of a system of coordinates in X and in Y ("Messtechnische Mitteilungen" of Siemens AG, Messgeràte Messsysteme - Prtifautomaten, Noves 1972). The writing head is provided with a tracing style which, in the case of a multicolored recording, is likely to be replaced by tracing styles of other colors. The tracing styles of different colors can be located in a fixed magazine from which the writing device picks up the necessary tracing style, in response to corresponding ordering instructions. Such a multicolored writing device comprises, for the change of the tracing style, a relatively expensive mechanical arrangement. The frequent raising and lowering of the tracing styles, leads, moreover, to a strong wear of the tracing styles which are, in as a general rule, made up of fiber styles. The recording devices constituted as just indicated are designated by "Rotter", and they are also used as output devices in installations for data processing.

 In fact, we know, for the reproduction of alpha-numeric signs, writing heads with the help of which the signs are constituted by mosaics of individual points.

The individual dots are produced using ink cannons capable of being excited by piezoelectric means, said ink cannons ejecting for each excitation pulse, a droplet of ink at the level of an ejection nozzle which is located at the end of the ink gun (patent
US N 3,298,030 and patent application published in the Republic
Federal Republic of Germany under NO 25 43 420).

 Starting from a recording device with a writing device for the automatic drawing of curves, diagrams or images in a fixed spatial system of coordinates in X and in Y, of the type constituted by a transportable writing head, arranged above the writing plane and with which are associated at least two tracing styles or styli, the object of the invention is to reduce the reaction time of the writing head by improving the construction of the writing device .

To this end, it is provided, by the invention, that the tracing styles are constituted by known ink cannons, provided with ejection nozzles and capable of being excited by piezoelectric means, and that the ink cannons which are provided for lines of the same color are arranged in large numbers and in a fixed position in the writing head with their injection nozzles parallel to one of the coordinate axes, and uniformly distributed along a line, as well as at a some distance from the writing plane.

In a recording apparatus thus produced, the necessary movement of the writing head in a direction of one of the coordinate axes can be replaced totally or partially by an electric control of the ink cannons arranged along lines. Advantageously, the arrangement of the ink cannons along lines extends over the entire length of one of the coordinate axes so that one can completely renounce a displacement of the writing head in this direction. However, one can also consider dividing the movement of the writing head in the direction of one of the coordinate axes into two or even three basic positions, the intermediate positions which are necessary possibly being obtained by a command. corresponding ink cannons.

The recording device, intended - first of all for a plot in one color, can therefore be supplemented. For a multicolored plot by arranging the ejection nozzles of ink cannons for plots of different colors along several lines parallel and by providing such a spatial position of the ejection nozzles that the axes of nozzles adjacent to different lines intersect the writing plane at a point.

The color change can therefore be carried out in a particularly simple and rapid manner without the need to use an expensive mechanism. The passage from a line of a specific color to a line of another color takes place practically without loss of time. Since the ejection nozzles of ink cannons of different lines, and which are adjacent to each other, are directed at a same point of the writing plane, the change from one color to another can be carried out without interruption . We can also do without a particular adjustment of the tracing styles, in connection with the problem of color change. Wear and tear of tragic styles or styli is practically eliminated.

 The coordination of the ink cannons with one another in the writing head is advantageously carried out in such a way that the outlet openings of the ejection nozzles arranged along a line are spaced apart by less than 1 mm.

As a result, sufficient resolution is obtained. In addition, it is desirable that the axial distance between the outlet openings of the ejection nozzles and the writing plane is the same for all the ejection nozzles. This axial distance is advantageously of the order of 2 mm. It is thus certain that during a continuous displacement of the writing head with a speed of approximately 0.25 m / sec and for an exit speed of the droplets d ink of approximately 4 m / sec, the maximum error of the trace is 0.125 mm, therefore low enough to be neglected.

Two embodiments of a writing head according to the invention are shown diagrammatically in FIGS. 1 and 2.

Figure 1 shows at a distance d from the writing plane 1 the writing head 2 in the form of a beam, and in which there has been arranged, in the manner of the teeth of a comb, in a row or a line, a large number of ejection nozzles 3 which belong to ink cannons not shown in detail and capable of being excited by piezoelectric means.

The ejection nozzles 3 are spaced about 0.3 mm apart and the distance d to the plane of the paper is to twist 2 mm.

The writing head extends over the entire writing plane, in the direction of the X coordinate axis, and it is movable in the direction of the Y coordinate axis. For drawing a curve or of a diagram, one excites, in a short sequence, one of the ejection nozzles 3, so that an ink droplet 4 is ejected and forms for example the point A.

According to FIG. 2, the writing head 10 has been placed above the writing plane 1 in which are arranged, for a multicolored drawing of curves or diagrams, the ejection nozzles 11, 12 and 13 belonging to different color ink cannons. In the manner not shown, to each ejection nozzle 11, 12, 13 belongs a whole line of ejection nozzles of the same color and which, according to the representation of FIG. 1, are arranged in the longitudinal direction of the axis of the coordinates in X. In the case of the writing head 10, the axes a of three adjacent ejection nozzles of different lines intersect at a point A of the writing plane, so that the ink droplets 14, 15 or 16 which are ejected individually or simultaneously or alternatively successively to produce a mixing color, trace the same point A.

 In the representation according to FIG. 2, the outlet openings of the ejection nozzles 11, 12 and 13 are arranged on a circular arc whose center coincides with the point A and whose diameter is approximately 4 mm.

Claims (4)

 1. Recording apparatus with writing device for the automatic drawing of curves, diagrams or images in a fixed spatial system of coordinates in X and in Y, of the type constituted by a transportable writing head, arranged above the plane writing and which are associated with at least two tracing styles or styli, characterized in that the tracing styles or styli are constituted by known ink cannons, provided with ejection nozzles (3) and capable of being excited by piezoelectric path and that said ink guns which are intended for traces of the same color are arranged in large numbers and in a fixed position in the writing head (2) with their ejection nozzles (3) parallel to one of the axes (X) of the coordinates and uniformly distributed along a line as well as at a certain distance (d) from the writing plane. 2. Recording apparatus according to claim 1 for a multicolored trace, characterized in that the ejection nozzles (11, 12, 13) of the ink cannons adapted for a multicolored trace are arranged in several parallel lines and that the axes (a ) nearby injection nozzles of different lines intersect at a point (A) of the writing plane.  3. Recording device according to claim 1 or 2, characterized in that the openings of the ejection nozzles (3) arranged in a line, are spaced apart by less than 1 mm.  4. Recording apparatus according to any one of. Claims 1 to 3, characterized in that the axial distance between the outlet openings of the ejection nozzles (3, 12, 13, 14) and the writing plane is approximately 2 mm.