CARD HOLDING PRINTABLE TAGS TO MAKE IDENTIFICATION MARKS FOR CABLES AND ELECTRIC COMPONENTS AND METHOD OF PRINTING IDENTIFICATION MARKS ON SAID TAGS
D e s c r i p t i o n
The present invention relates to a card holding printable tags to make identification marks for cables and electric components, of the type comprising the features set out in the preamble of claim 1.
The invention also relates to a method of printing identifications marks for cables and electric components.
In the accomplishment of electric systems, particularly either in buildings or on industrial-use machinery, appropriate code marks are known to be associated with the electric cables and the electric equipment such as switches, contactors, terminals or others, in order to enable easy identification of the executed wiring so that subsequent control operations and/or new wiring operations are facilitated, when servicing and/or repair interventions are required.
In many cases, these identification marks or codes are reproduced on small tags of plastic material with which the cables or the electric equipment are engaged also through connecting lugs jutting out on one base side of the tag itself.
Tags are usually made by an injection-moulding step. In more detail, by a single injection-moulding operation at least one card is produced which has a substantially flat conformation and is made up of at least one moulding deadhead or sprue to which a plurality of tags is linked by frangible connecting portions. Said tags lend
themselves to be individually separated, in case of need, by breaking of the respective frangible portion.
The code marks are written on the tags at a later time, by a plotter essentially comprising at least one pen-nib movable along two orthogonal axes over a table on which the card is disposed. Operation of the plotter is governed by an electronic processor in which the work program for writing the code marks on the individual tags is stored.
During the last two decades and even earlier, i.e. since the code mark writing method with the aid of a plotter was proposed on the market, great efforts have been made in trying to improve the plotters'1 efficiency, particularly in terms of writing speed and accuracy in the performed work. In order to give some information on the results hitherto achieved, it should be pointed out that writing of six-alphanumeric-character codes on a card containing 59 4x4 mm tags is completed in a period in the order of 6 minutes.
Under this circumstance, for manufacturing the above specified tags, use of plotters has been always considered as satisfactory and indispensable for accomplishing code writing in an automated, versatile, sufficiently quick and accurate manner.
All that being stated, the Applicant has tried to cope with the problem of reproducing marks also of the chromatic type on the tags, for example comprising alphanumeric characters disposed on a coloured background of one or more colours, and/or bar codes presently unsuitable to be conceived with the aid of plotters; thus the Applicant has become aware of the fact that by replacing the writing methods using plotters with
printing methods involving hot transfer, thermal transfer or ink sublimation, the problem highlighted above can be solved and a surprising increase in the versatility and flexibility of - the types of marks suitable for reproduction on tags can be achieved. Such a printing method described in the Patent Application EP 1 058 201 in the name of the same Applicant, has also enabled a drastic reduction in the time necessary to reproduce the coded marks on the tags .
In spite of the above, at the present state of the art printing by thermal transfer has shown some difficulties in obtaining satisfactory qualitative results.
In accordance with the present invention, the Applicant has found that the causes of such difficulties are to be ascribed to an insufficient geometric and dimensional accuracy of the tags made in accordance with the known art. In particular it was possible to see that the presence of the connecting lugs jutting out on the base side of each tag to enable engagement of same with cables or electric components with which it is intended to be associated involves draw phenomena due to cooling taking place at the end of the injection moulding operation carried out for card manufacture, which phenomena cause slight flaws in the planar surfaces of the tags to be printed. These flaws have been always neglected because they do not give rise to particular problems in code printing by plotter, but they appeared unexpectedly dangerous with reference to the execution of a printing process by thermal transfer or ink sublimation.
In accordance with the present invention, it was found that by arranging engagement lugs geometrically structured in such a manner that said draw phenomena are prevented, excellent results can be achieved in terms of
printing even with the printing methods by thermal transfer.
In more detail, it is an object of the present invention to provide a card holding printable tags to make identification marks for cables and electric components, characterized in that it comprises the features set out in the characterizing portion of claim 1.
In a further aspect of the invention, it is also an object of the invention to provide a method of printing identifications marks for cables and electric components on a tag-holding card, in particular a card holding printable tags as claimed in claim 1, as defined in claim 4.
Further features and advantages will become more apparent from the detailed description of a preferred, but not exclusive, embodiment of a card holding printable tags to make identification marks for cables and electric components, and of a method of printing these identification marks, in accordance with the present invention.
This description will be taken hereinafter with reference to the accompanying drawings, given by way of non- limiting example, in which:
- Fig. 1 is a perspective view of a tag-holding card in accordance with the present invention, disposed on a support associated with a thermal-transfer printer;
- Fig. 2 is a plan view of the card and support shown in Fig. 1;
- Fig. 3 shows a section taken along line III-III in Fig. 2, to an enlarged scale; - Fig. 4 shows a detail of the card in Fig. 2 to an enlarged scale, seen in a direction opposite to that in
Fig. 2.
With reference to the drawings,, a card holding printable tags to make identification codes for cables and electric components in accordance with the present invention has been generally identified by reference numeral 1.
Card 1 comprises a plate-like support 2, preferably of plastic material and of substantially rectangular conformation which is made by injection moulding.
Support 2 is provided with slits 4 such shaped as to delimit a plurality of tags 5 connected with at least one deadhead or sprue 6.
Tags 5 are supported by the sprue 6 through frangible connecting portions 7. Each connecting portion 7 is made up of a flap of the plate-like support 2 of smaller sizes that those of tag 5 and of reduced thickness, to enable e'asy breaking of. same when tags 5 are to be cut off.
Preferably, card 1 comprises a plurality of sprues 6 of elongated shape and mutually interconnected by auxiliary frangible connecting portions 8.
Sprues 6 are disposed parallel to, and suitably spaced apart from each other; along a major side 9 of each sprue 6 a tag series 5 is attached that takes up the space between one sprue and the next one .
According to possible alternative embodiments not shown, tags 5 lying between two adjacent sprues 6 can be connected to both of the sprues 6 or alternately to only one of them.
Preferably, to facilitate cutting off of tags 5, each tag
has a single connecting portion 7 placed on one attachment side 10 thereof.
All tags 5 of a series are connected to a single sprue 6 so that all attachment sides 10 are oriented in the same direction.
The plate-like support 2 further has a flat face 11 adapted to be printed with a printing machine or press by thermal transfer 12.
Each tag 5 therefore has a printable surface 13 coplanar with an upper face βa of the respective sprue 6 and being part, together with said sprue, of the flat face 11 of support 2.
Preferably at least one connecting lug 15 projects from a base side 14 of each tag 5 opposite to the printable surface 13; said lug is adapted to fasten the tag 5 itself to cables or electric components such as terminals, contactors, connectors, etc. (not shown) , on laying of same.
Each lug 15 is joined, by a small attachment surface, to the base side 14 and is geometrically structured in such a manner that draw effects on the printable surface 13 are prevented during cooling of the material.
In order to avoid said draw effects, the minimum linear dimension "1" of the attachment surface concerned with lug 15 is smaller than the thickness "t" of tag 5.
In particular, the attachment surface in a plane parallel to the printable surface 13 has at least one dimension "1" smaller than 1/3 of the thickness λt" of tag 5 as measured between the printable surface 13 and the base
side 14. Preferably, the overall volume of each connecting lug 15 is provided to be smaller than 1/3 of the overall volume of tag 5.
Still in accordance with the present invention, a method of printing identification codes for cables and electric components on a tag-holding card is now described.
In particular, this method is adapted to print codes on each tag 5 of a tag-holding card 1.
Card 1 is disposed on a rest element 17 to supply a steady and flat support surface for insertion in a printing machine of the thermal transfer type 12.
Preferably the rest element 17 is formed of an elastically yielding substrate 18 in which provision is made for appropriate housings 19 for the lugs 15 and appropriate holes 20 for respective dowels 21 projecting each from a base side βb of the respective sprue β opposite to the upper face 6a.
The substrate stiffness is much lower than that of the card 1 to enable suitable arrangement of each tag 5 during printing.
In addition, the substrate 18 can be placed on a platelike counter-element 22 to ensure more stiffness to the assembly.
Tags 5 are submitted to a printing treatment by hot transfer, thermal transfer or ink sublimation on respective printable surfaces 13 facing away from a base side 14 put in contact with the elastically yielding substrate 18.
In the same manner as described in the above mentioned document EP 1 058 201, the printing treatment involves the step of moving a ribbon-like carrier known by itself and therefore not shown and carrying at least one ink layer, close to the printable surfaces 13 of tags 5; a printing head being part of a printing machine of the thermal transfer type 12, governed by an electronic processor, heats the ribbon-like carrier and the tags 5 at least on one portion of the respective surfaces disposed in mutual side by side relationship to cause ink transfer from the ribbon-like carrier to the tag 5.
Transfer takes place concurrently with passage of the plate-like counter-element 22, card 1 and substrate 18, under the printing head in a forward stroke and a return stroke.
As shown in Fig. 1, card 1 put on the yielding substrate 18 and on the plate-like element 22 is laid down on a drawer 23 of the printing machine 12; drawer 23, retracted into the machine 12, makes card 1 pass under the printing head, said card being then extracted again following the return stroke so that it is made available to a user. Alternatively, the card 1, substrate 18 and possible plate-like element 22 can be introduced into a printing unit as described in document EP 1 058 201.
The present invention achieves important advantages.
First of all an improved print quality can be achieved due to the perfect planar character of the tag surfaces enabling a uniform distribution of the ink thereon and to the possibility of the tags of settling down on the yielding substrate during passage under the printing head, which ensures a perfect parallelism between the tags themselves and the printing head.
In addition, accuracy in the translation movement of the drawer to which the card is linked enables either printing to be carried out in different passages or a faulty print to be corrected, being always sure that during each passage the head accurately and faithfully follows the already written regions.
Finally, the method is very flexible because it allows printing to be carried out on cards of different sizes and shapes after possibly replacing either the yielding substrate alone or the stiff counter-element too.