FR2476303A3 - Multi-colour graphical recording device - has recording head movable in coordinate directions and incorporating several ink jets - Google Patents

Abstract

The recording device, for curves diagrams etc., has a recording head (2) with at least two different coloured recording pens. Each of these comprises a piezoelectrically operated ink jet (3,4,5) and they are fixed in position relative to the head (2) so that the axes (a) run parallel to one another or intersect at a point (A) within the plane of the recording surface (1). Pref. the axial distance of the outlet opening of each ink jet (3,4,5) from the recording surface (1) is about 2mm. The recording head (2) can be moved across the recording surface at a rate of 0.25 m/sec with the ink droplets projected at a velocity of 4 m/sec. The max. recording error for these parameters is 0.125 mm. The unit allows the colour of the printing ink to be rapidly altered and uses a recording head (2) of simple construction.

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 recording device with two coordinates.

In the recording of measured values by plotting measuring devices, an interest attaches, inter alia, to the reciprocal behavior between two measured quantities, possibly their interdependence. The corresponding measuring devices are provided with a writing device whose writing head which is arranged above the writing plane, is capable of being moved in the two directions of a system of coordinates in X and in Y ("Messtechnische Mitteilungen" of Siemens AG, Messgeràte
Messsysteme - Prûfautomaten, Nov. 1972). The writing head is provided with a tracing style which, in the case of a multicolored recording, is likely to be replaced by tragic styles of other colors. The tracing styles of different colors may be located in a fixed magazine from which the writing device takes the necessary tracing style, in response to corresponding control 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, as a rule, made up, by fiber styles. 'to be indicated are designated by "Plotter", and they are also used as output devices in installations for data processing.

In fact, for the restitution of al-jha-numerical signs, we know writing heads with the help of which the signs consist of mosaics of individual points and individual points are produced using ink cannons likely to be piezoelectrically excited,
Said ink cannons ejecting, for each excitation pulse, a droplet of ink at the level of an ejection nozzle which is at the end of the ink cannon (patent
US Lv 3,298,030 and patent application published in the Republic
Federal of Allemag, do not sos N 25 43 4209.

 Starting from a recording device comprising a writing device for the automatic and multicolored drawing of a diagram or image curve in a fixed coordinate system in X and in Y, in which the writing device consists of a writing head situated above the writing plane and capable of being transported, of the type comprising at least two writing styles of different colors and associated with the writing head, the object of the invention is to reduce the operation of color change by improving the construction of the writing device.

 For this purpose, the tracing styles or styli consist of ink cannons capable of being excited by piezoelectricity and provided with nozzles, said ink cannons are arranged in a fixed position in the writing head and the axes of the nozzles which are located at a certain distance from the writing plane are parallel to each other or intersect at a point located in the writing plane.

 In a recording apparatus thus produced, the complex mechanism for the color change is first removed. Linked to this is a notable shortening of the color change operation. This is assisted by the genre and layout of the tracing styles used.

The transition from an ink gun capable of being excited by a piezoelectric path to another gun takes place practically without loss of time. Since the ejection nozzles of the ink cannons which are arranged in a fixed position in the writing head are each directed at the same point of the writing plane, the change from one color to another can take place without interruption. It is also unnecessary to make any particular adjustment of the tracing styles in connection with the color change. A wear of the tracing styles practically does not take place. by electronic measurements when ordering the writing head.

 The reciprocal arrangement of the ink cannons in the writing head is advantageously carried out in such a way that the axial distance of the outlet openings of the respective ejection nozzles to the writing plane is identical to that of all the ejection nozzles. This distance is advantageously around 2mm. It is thus ensured that during a continuous displacement of the writing head, at a speed of approximately 0.25 m / sec and an exit speed of the ink droplets of approximately 4 m / sec, the error of trace is at most equal to 0.125 mm, therefore weak to the point of being able to be neglected.

 In Figure 1 attached, there is shown schematically an exemplary embodiment of a writing head provided in 1 t object of the invention.

 The figure shows, below the writing plane 1, a writing head 2 in which are fixed three ink guns, not shown in detail, and capable of being excited by piezoelectric path, as well as the ejection nozzles 3, 4 and 5. The latter are adjusted so that their axes a intersect at point A located in the writing plane 1. I7 is further provided that the distance from the outlet openings of the ejection nozzles is the even for all the ejection nozzles, that is to say that the outlet openings are located on an arc of a circle or on a portion of a sphere whose center is located at point A.

 When multicolored recording, the ink guns which are associated with the ejection nozzles can be excited individually or simultaneously. A simultaneous excitation of two or more guns would lead to a mixture of the ejected ink droplets 6,7 and 8 and, consequently, to the production of a mixture color.

Claims (2)

R E V E N D I C A T I 0 N S  1. Recording device with writing device for the automatic and multicolored drawing of curves, diagrams or images in a system of coordinates in X and in Y fixed in space, constituted by a transportable writing head, placed above above the writing surface and with which are associated at least two tracer pens of different colors, characterized in that the tracer pens consist of ink cannons capable of being excited by piezoelectric path and provided with nozzles (3, 4, 5), that said ink cannons are disposed in a fixed position in the writing head (2) and that the axes (a) of the nozzles which are located at a certain distance from the writing plane (1) are parallel between them and intersect at a point (A) located in the writing plane.  2. Recording apparatus according to claim 1, characterized in that the axial distance between the outlet opening of the nozzles (3, 14, 5) and the writing plane (1) is of the order of 2 mm.