SYSTEM FOR REGULATING INK INJECTOR SUPPLY IN A PRINT HEAD AND PRINTING EQUIPMENT INCLUDING SAME

Abstract

The present invention relates to a system for regulating ink injector supply in a print head, of the type installed in printing equipment and that use ink injectors which, by the installation of a measurement assembly parallel to the head and configured to emulate said print head, allows making an ink pressure measurement that does not require placing the ink system next to the head and prevents the use of pressure sensors with a wide range, using a single sensor without having to known the elevation of the head with respect to the system, nor the density of the liquid, or even the variation of viscosity with temperature.

Claims

1. A system for regulating ink supply to injectors of a print head with ink recirculation system, characterised in that the system for regulating ink supply comprises at least one measurement assembly installed parallel to the flow of ink to the injection head emulating conditions of said injection head, where the measurement assembly of the system for regulating ink supply comprises at least: a pressure measurement point to which a pressure sensor is connected; a first connection of the pressure measurement point (11) in an ink supply inlet circuit of the print head; and a second connection of the pressure measurement point in an ink supply outlet circuit of the print head; where the first and second connections of the measurement point to each of parts of an ink supply circuit have identical characteristics of hydraulic resistance to ink flow; and where each connection of the measurement point to each of the parts of the ink supply circuit includes at least one or more conduct segments and connection elements to the ink supply circuit, where the hydraulic resistance to ink flow from the point of connection of the measurement assembly at the ink inlet circuit of the print head to the pressure measurement point is identical to the hydraulic resistance to ink flow from the pressure measurement point to the connection point of the measurement assembly at the supply outlet circuit of the print head.

2. The system for regulating ink supply to the injectors of a print head, according to claim 1, where the pressure measurement point is located at an elevation identical to the elevation of the central area in which the injectors are placed.

3. The system for regulating ink supply to the injectors of a print head, according to claim 1, where the pressure measurement point is placed at an elevation identical to the elevation of the central area in which the injectors are placed.

4. The system for regulating ink supply to the injectors of a print head, according to claim 1, where the elevation of the measurement point of the measurement assembly installed parallel to a print head with a vertical orientation corresponds to the mean elevation of the various injectors distributed vertically in the print head.

5. The system for regulating ink supply to the injectors of a print head, according to claim 1, where the elevation of the measurement point of the measurement assembly installed parallel to a print head with a horizontal orientation corresponds to the elevation of any of the injectors in the print head, as this elevation is defined by the horizontal distribution of the injectors.

6. The system for regulating ink supply to the injectors of a print head, according to claim 1, where the ink supply system for the injectors has a control system that receives information from the pressure measurement assembly by the pressure sensor at the measurement point, regulating the pressure in the ink recirculation circuit according to predetermined parameters by acting on the ink pumping/suctioning means.

7. An ink printing equipment of the type that print ink on a surface or support and formed by at least one ink supply system to at least one print head, characterized in that the print head comprises the system for regulating the ink supply of the injectors in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] For the better understanding of the description made herein, a set of drawings has been provided wherein, schematically and solely by way of a non-limiting example, a practical case of an embodiment is portrayed.

[0041] FIG. 1 is a schematic view of a possible operation scheme for a supply system in which the measurement assembly is integrated, showing the pumps, auxiliary reservoirs, filters, stabilizers etc. that form part of the supply system but which are not part of the specific novel features of the invention as they are known conventionally, yet do form part of the system in which the invention is integrated.

[0042] FIGS. 2a and 2b are respectively a partial side view of a head showing the manifolds and the conducts containing the injectors and a schematic view of the measurement assembly with the measurement point at the central area and the connection elements to the manifold.

[0043] FIG. 3 is an upper plan view of a print head with a horizontal orientation.

[0044] FIG. 4 is a side plan view of a print head with a vertical orientation.

DESCRIPTION OF A PREFERRED EMBODIMENT

[0045] Various embodiments of the present invention of a system for regulating supply to the ink injectors of a print head are described below, as well as of the printing equipment including same, with reference to the aforementioned figures.

[0046] According to the present invention, as can be seen in FIG. 1, the preferred embodiment of the invention is based on an ink printing equipment (100) that is provided with a horizontally arranged print head (200) and injectors (201) fed by an ink supply system (300), which is provided with an ink regulation system with recirculation through said injectors (201).

[0047] The heads are fed by an ink inlet circuit (301) which supplies ink, according to the present embodiment, to a first manifold (202) for ink inlet to the injection chamber of the head (200), a second manifold (203) arranged for ink outlet from the injection chamber of the head (200) that opens into the outlet (302) and return circuit of the ink to the reservoir (303).

[0048] Between each manifold (202, 203) are conducts that communicate them, the ink ejection injector (201) being located at the central area of each conduct.

[0049] As can be seen in FIGS. 1, 2 and 3, connected on one side to the inlet circuit (301) and one the other to the outlet circuit (302) of the head (200), and therefore in a parallel flow of ink to same, is a measurement assembly (10) that forms part of the supply regulation system and that includes a measurement point (11).

[0050] This measurement point (11) emulates the pressure conditions of the injectors (201) such that it has a measurement point (11) at the central part of said communication between the inlet circuit (301) and the outlet circuit (302). The measurement point (11) has a connection to a pressure sensor (12) to obtain this pressure and supply the data to the supply regulation system.

[0051] The segments (13, 14) of the conduct before and after the measurement point (11) have the design requirement that the first connection segment (13) of the pressure measurement point (11) to the inlet circuit (301) for ink supply to the print head (200), and the second connection segment (14) of the pressure measurement point (11) to the outlet circuit (302) for ink supply to the print head (200), must have identical characteristics of hydraulic resistance to ink flow in each one (13, 14).

[0052] In the present preferred embodiment, as shown in FIG. 3, the pressure measurement point (11) emulates a horizontally-arranged print head (200), and thus said measuring point (11) is at an elevation (h) identical to the elevation (h′) defined approximately by all the injectors (201) of the head (200).

[0053] The location of the elevation (h) of the measurement point (11) can vary and not be identical to the elevation (h′) of the injectors (201), normally due to problems of available space in the connection of the inlet circuit (301) and the outlet circuit (302), and to the external location of the injectors (201), but this variation must be minimised so that the measurement is as correct as possible. Alternatively, the measurement point could be placed at a different elevation, although this will lower the accuracy of the measurement obtained.

[0054] In this regard, and alternatively, if the head (200′) has a vertical orientation, as can be seen in FIG. 4, the pressure measurement point (11′) emulates a print head (200′) with a vertical orientation, and is therefore located at an elevation (h) identical to the elevation (h′) approximately resulting from the mean of the elevations at which the injectors (201′) are distributed in the head (200′).

[0055] Each connection segment (13, 14) of the measurement point (11) to each of the corresponding parts of the ink supply circuit (301, 302) includes a connection element (15) to the supply circuit and a conduct (16), in the form of a narrowing, where this narrowing is formed by a capillary with a cross-section diameter of 1 mm.

[0056] As indicated this configuration must comply with the requirement that the segment (13) before and the segment (14) after the measurement point (11) have identical hydraulic resistance to flow. To this end in the present embodiment the two segments (13, 14) have the same physical characteristics, lengths and sizes.

[0057] The pressure at the measurement point (11) is obtained by a pressure sensor (12) that automatically supplies this information, according to any of the conventional communication means known, to the system for regulating ink supply to the head (200), which allows obtaining accurate information on the ink pressure at the injectors (201) of the print head (200) by emulating the conditions thereof at the measurement point (11) and allowing to regulate the pressure of the supply ink.

[0058] Regulation is performed in view of the parameters assigned for specific printing conditions, determined by the characteristics of the ink, temperature, support, etc. by acting on the actuation elements of the supply system (300), mainly on the pumping devices (304).

[0059] Despite the fact that reference has been made to a specific embodiment of the invention, it is evident for a person skilled in the art that the system for regulating ink supply to the injectors of a print head, as well as the printing equipment including same, as described are susceptible of numerous variations and modifications, and that all the aforementioned details can be replaced by other technically equivalent ones without detracting from the scope of the protection defined by the attached claims.