GB2435447A

GB2435447A - Conduit for continuous inkjet printer

Info

Publication number: GB2435447A
Application number: GB0526150A
Authority: GB
Inventors: Peter Sidney Frank Hutchinson
Original assignee: Domino Printing Sciences PLC
Current assignee: Domino Printing Sciences PLC
Priority date: 2004-12-30
Filing date: 2005-12-22
Publication date: 2007-08-29
Also published as: GB0526150D0; GB0428480D0

Abstract

A conduit (20) for linking the printhead to the processor of a continuous inkjet printer. The conduit (20) includes enclosed channels (21,22) so that volotile liquids are kept isolated from electrical signal lines (19). Further, the conduit preferably has a preferred bending axis which assists with the accurate positioning of the printhead. The channels (21, 22) are kept apart by barrier (24).

Description

IMPROVEMENTS IN OR RELA TING To CONTINUOUS INJET PRINTERS

Field of the Invention

This invention relates to a continuous inkjet (Cli) printer.

Background to the Invention

CIJ printers are widely used in industrial marking and coding applications. In such applications, the typical Cli printer has a printhead located adjacent a moving production line, and a processing section located some distance apart. The processing section includes ink and solvent storage, one or more pumps to convey ink and solvent to the printhead, and electronic hardware, firmware and software to control the operation of the printer whereby ink is converted into droplets and directed, in a controlled manner, on to objects moving along the production line.

A multiplicity of lines convey fluids and electronic signals between the processing section and the printhead. These lines are typically held in a common conduit.

There are a number of problems associated with existing conduits. Firstly, lines containing inks and solvents are bundled in with lines conveying electrical charges.

Given that the inks andlor the solvents invariably contain volatile components, the environment within the conduit contains carriers of flammable vapours as well as potential sources of sparks which could ignite those vapours.

The second problem is that existing conduits containing a large number of lines and cables are bulky and difficult to bend. This, in turn, can make the task of positioning the printhead difficult, simply because the limited flexure of the conduit can limit available positions of the printhead.

It is an object of this invention to provide a continuous inkjet printer, and/or one or more components therefore, which will go at least some way in addressing aforementioned problems; or which will at least provide a novel and useful choice.

Summary of the Invention

Accordingly, in one aspect, the invention provides a continuous inkjet printer including a printhead; a processing section; a plurality of fluid conveying lines extending between said printhead and said processing section; a plurality of electrical signal conveying lines extending between said printhead and said processing section; and a flexible conduit enclosing said fluid conveying lines and said electrical signal conveying lines, said printer being characterised in that said flexible conduit includes a first enclosed channel in which said fluid conveying lines are located; and a second enclosed channel in which said electrical signal conveying lines are located, said first channel being sealed from said second channel.

Preferably said conduit has a preferred bending axis.

Preferably said conduit has a non-circular cross-section.

Preferably said conduit has a generally oval shaped outer surface when viewed in cross-section.

Preferably the part of said conduit defining the barrier between said first and second channels has a varying thickness.

Preferably said first channel is of substantially the same form and dimensions as said second channel.

Preferably the walls defining said first and second channels are substantially circular in cross-section.

In a second aspect the invention provides a method of organising components in a continuous inkjet printer having a printhead; a processing section; a plurality of fluid conveying lines extending between said printhead and said processing section; and a plurality of electrical signal conveying lines extending between said printhead and said processing section; said method being characterised in that said fluid conveying lines are located in a first enclosed channel of a conduit; and said electrical signal conveying lines are located in a second enclosed channel of said conduit, wherein said first channel is sealed from said second channel.

In a fifth aspect the invention provides a conduit for containing fluids conveying lines and electrical signal conveying lines of a continuous inkjet printer, said conduit being characterised in that it has a first enclosed channel for said fluids conveying lines and a second enclosed channel for said electrical signal conveying lines, said first channel being sealed from said second channel.

Many variations in the way the present invention can be performed will present themselves to those skilled in the art. The description which follows is intended as an illustration only of one means of performing the invention and the lack of description of variants or equivalents should not be regarded as limiting. Wherever possible, a description of a specific element should be deemed to include any and all equivalents thereof whether in existence now or in the future.

Brief Description of the Drawings

The various aspects of the invention, in one preferred form, will now be described with reference to the accompanying drawings in which: Figure 1: shows an elevational view of a typical continuous inkjet printer installation; and Figure 2: shows, in a much enlarged scale, a view along the line 2-2 in Figure 1.

Detailed Description of Working Embodiment

Referring firstly to Figure 1, the present invention has application to a continuous inkjet (CIJ) printer used, for example, for industrial marking and coding. To this end, the printer includes a printhead 10 and a processing section 12, the processing section 12 including sources (not shown) of ink and solvent together with hardware, firmware and software to control the operation of the Cli printer. All this is well known and the precise nature of these components does not form part of this invention.

The printhead 10 is fixed to a mounting bar 14 by a releasable clamp 15. This allows the position of the printhead to be adjusted and fixed with respect to a conveyor 16 on which components to be marked by the Cli printer, are conveyed past the printhead.

In the known manner, a multiplicity of fluid lines 18 (Figure 2) and a multiplicity of electrical signal conveying lines 19 (Figure 2) interconnect the printhead 10 and the processing section 12. These are conveniently retained in a conduit 20.

In prior art Cli printers, the conduit 20 is typically defined by a length of flexible tube of annular cross-section. The lines 18 and 19 are gathered together and placed inside the conduit. With the increasing functionality now demanded from Cli printers, there are a large number of individual lines and, as a result, the flexibility of the conduit 20 is becoming more limited. Depending on the relative positions of the printhead 10, the processing section 12 and the mounting bar 14, this can lead to difficulties in precisely positioning the printhead. Further, there is a concern about housing together, lines containing volatile inks and/or solvents, with lines carrying electrical charges.

Turning now to Figure 2, in accordance with one aspect of the invention the fluid conveying lines 18 are gathered together and placed in a first channel 21 of the conduit whilst the electrical signal conveying lines 19 are gathered together and placed in a second channel 22 within the conduit. The channels 21 and 22 are sealed from one another by a barrier 24 comprising part of the conduit moulding. Whilst the electric signal lines 19 are kept separate from the fluid lines, an electrical earth cable is preferably provided within the channel 21 and, in the form shown, is located substantially centrally within the cluster of fluid lines.

As can be seen, the outer surface of the conduit 20 is generally oval in form and has a short axis of symmetry Y -Y and a longer axis of symmetry X -X. The channels 21 and 22 are preferably identical in form and dimensions and are conveniently defined by substantially round-walled cavities within the conduit. The channels 21 and 22 are also arranged evenly with respect to the axes of symmetry X -X and Y -Y. Given that the channels 21 and 22 are circular or substantially circular in section, the barrier 24 between the channels has a section of varying thickness and, as can be seen, the point of minimum thickness preferably lies on the axis X -X. This is particularly advantageous in that it reduces still further, the effort required to deform the conduit about axis X -X, the preferred bending axis and thus makes it much easier to accurately position the print head 10.

A liner 26 is preferably provided about the inner periphery of channel 22 to provide EMC shielding, and the electrical cables 19 may be further arranged in a pre-defined manner to reduce signal cross-talk between lines.

In one method of assembly, the electrical cables 19 are inserted into the channel 22 whilst the fluid lines 18 are inserted into channel 21. Because the channels 21 and 22 are both circular in section, a twisting motion can easily be applied between the conduit and the bundles of lines which greatly assists the insertion process. In another method of assembly, the clusters of cables or lines 18 and 19 are drawn through an extrusion die and the material defining the conduit moulded about the clusters to define the overall configuration depicted and described. To impart a generally round section to the clusters, packing elements 28 may be added thereto.

It will be appreciated that, when the conduit is formed or assembled according to the second method described above, machine set-up is considerably simplified as a length of conduit can simply be cut to length from a roll, the ends of the lines prepared, and the lines then connected between the printhead 10 and the processor 12.

It will thus be appreciated that the present invention, at least in the case of the working embodiment depicted and described, has a number of advantages over existing CIJ assemblies, namely: i) The umbilical provides circular-section channels to receive the line bundles and thus allow the bundles to be inserted in the known, effective manner.

When assembled the fluids and electrical bundles are isolated from one another.

ii) The assembled conduit and lines has a readily obvious preferred axis of bending which eases the task of positioning the printhead and maintaining the alignment thereof.

Claims

Claims 1) A continuous inkjet printer including a printhead; a

processing section; a plurality of fluid conveying lines extending between said printhead and said processing section; a plurality of electrical signal conveying lines extending between said printhead and said processing section; and a flexible conduit enclosing said fluid conveying lines and said electrical signal conveying lines, said printer being characterised in that said flexible conduit includes a first enclosed channel in which said fluid conveying lines are located; and a second enclosed channel in which said electrical signal conveying lines are located, said first channel being sealed from said second channel.

2) A printer as claimed in claim 1 wherein said conduit has a preferred bending axis.

3) A printer as claimed in claim 1 or claim 2 wherein said conduit has a non-circular cross-section.

4) A printer as claimed in any one of claims I to 3 wherein said conduit has a generally oval shaped outer surface when viewed in cross-section.

5) A printer as claimed in any one of the preceding claims wherein that part of said conduit defining the barrier between said first and second channels has a varying thickness.

6) A printer as claimed in any one of the preceding claims wherein said first channel is of substantially the same form and dimensions as said second channel.

7) A printer as claimed in any one of the preceding claims wherein the walls defining said first and second channels are substantially circular in cross-section.

8) A method of organising components in a continuous inkjet printer having a printhead; a processing section; a plurality of fluid conveying lines extending between said printhead and said processing section; a plurality of electrical signal conveying lines extending between said printhead and said processing section; said method being characterised in that said fluid conveying lines are located in a first enclosed channel of a conduit; and said electrical signal conveying lines are located in a second enclosed channel of said conduit, wherein said first channel is sealed from said second channel.

9) A conduit for containing fluids conveying lines and electrical signal conveying lines of a continuous inkjet printer, said conduit being characterised in that it has a first enclosed channel for said fluids conveying lines and a second enclosed channel for said electrical signal conveying lines, said first channel being sealed from said second channel.

10) A conduit as claimed in claim 9 further characterised in that it has a non-circular cross-section and a preferred bending axis.