GB2080736A

GB2080736A - Device for supplying current to a movable print head

Info

Publication number: GB2080736A
Application number: GB8118810A
Authority: GB
Original assignee: Kienzle Apparate GmbH
Current assignee: Digital Kienzle Computersysteme GmbH and Co KG
Priority date: 1980-07-24
Filing date: 1981-06-18
Publication date: 1982-02-10
Also published as: DE8019863U1; GB2080736B; FR2487260A1; FR2487260B1

Abstract

To avoid the use of a single flexible plate cable, which supplies electricity to a moving print head carriage 20, and which because of its weight may tend to kink or impose a drag on the carriage a pair of cables 23, 23' are used. These need have only half the number of leads and so avoid the above disadvantages. <IMAGE>

Description

SPECIFICATION Device for supplying current to a movable print head The invention relates to a device for supplying current by means of a flexible flat cable to a printing head arranged transversely movable in front of a printing support, for instance for the current supply to the printing magnets of a needle printer.

There is a great number of printers in which the print head is transversely movable in line direction in front of a printing support and in which during the passage of the print head printing symbols are produced on the printing support in that either a full character printing type is suddenly moved to the printing support by an electromagnetic or other driving means or in that the printing type is composed by printing signs in the form of dots. Printers of the last kind are for instance needle printers; but also electrostatic printers, ink jet printers and such like work according to the principle of composing the symbol to be printed out of dots. In each case the print head contains electrically controlled parts, for instance printing magnets or printing electrodes which must be energized by pulses.It is therefore always necessary to supply pulses for actuating the printing means from a fixed base part to the print head movable in line direction.

In order to allow for the flexible flat cables comprising several leads have already been used.

However, the more printing means there are to be operated individually or in combination the bigger is the number of leads to be introduced into the print head and the wider and heavier the flat cable to be used must be chosen. As a consequence hereof the cable has a tendency to bend due to its weight which can naturally lead to quite undesired damages to the cable. For this reason the cable has already been connected to metallic parts for stiffening the cable being fastened to such parts with clamps. This kind of stiffening the flat cables has, however, the disadvantage that the weight is additionally increased so that as a consequence hereof also the drive of the print head is loaded with this additional weight which is naturally undesired.It is also a disadvantage that in accordance with the length of movement of the print head the cable must have a considerable length and is therefore relatively expensive. It is therefore the object of the invention to introduce the flat cable from the base part of the printer to the movable print head in such a manner that the weight is not increased and that the cable is simultaneously safeguarded against any unwanted bending and as a consequence thereof against damages thereto. At the same time the cable should be as short as possible.

According to the invention a cable material is used which contains only approximately half of the necessary leads, one lane each of this cable material being led to the print head from the two sides thereof the introduction of the two lanes being arranged in the middle between the two end positions of the movement of the print head.

According to the further invention the cable lanes - I~ L ^ .. ..:A ~ S S TCl;e niiirln nark . ", U-shaped bar, in which the two lanes are supported and guided by the free shanks of the bar. At the two sides the individual leads of the flat cable are connected to plugs so that there is only a plug and socket connection between the print head, its current input leads and the base part through the flat cable.

Further details of the arrangement of the cable input to the movable print head according to the invention may be taken from the following specification of an embodiment of the invention. In the enclosed drawings Figure lisa top view of the total arrangement of the print head in its base part, Figure 2 is a side view of the print head and its cable input whilst Figure 3 is a special top view of the arrangement according to the invention.

According to Figure 1 between the plates 1 and 2 there are guide bars 3 and 4 on which the printing slide 5 is mounted and guided. In the printing slide 5 the print head 6 is arranged through the mouth 7 of which the printing needles protrude. To the slide 5 a driving belt 8 is fastened which is driven by a motor 9 via a small gear wheel 10 and other gearing parts which have not been shown in detail. The slide 5 with the print head 6 tabulates on the two guide bars 3 and 4 and the print needles arranged in the print head produce a corresponding printing sign on the print support 11.

To this end there is an endless ink ribbon 12 which is arranged between two cassette parts 13 and 14.

Thetwocasetteparts 13 and 14are arranged on a guide 15 which is fastened on top of the printer.

Figure 2 especially shows that the slide 5 which carries the print head 6 by means of two bushings 16 and 17 surrounds the two guide bars 3 and 4. The print head 6 itself is not immediately arranged on the printing slide 5 but in a frame part 18 which against the action of a spring is slidable on a shaft 19 in the slide 5. To make the print head 6 with its frame 18 slidable relatively to the slide 6 has the purpose to be able to set the distance between the openings for the printing needle in the mouth piece 7 and the printing support 11 in order to be able to take into consideration differing strength of paper. As a part of the frame 18 there is a plug part 20, in which a printed circuit plate 21 at the printing head 6 can be inserted.

Via the printed circuit plate 21 the individual electromagnets which drive the printing needles are supplied with driving pulses. The plug part 20 is connected to the individual leads 22 of the flat cable 23, which is spliced at its ends to be fastened to the plug 20.

The flexible flat cable 23 is guided in a guide part 24 in the form of a U-shaped bar. The two shanks 25 and 26 of this U-shaped guide part support the flexible flat cable on the outside. At the plug part 20 there are two guide parts 27 and 28 around which two lanes 23' and 23" of the flexible flat cable 23 are guided. The material of the flexible flat cable is chosen so that the number of available leads is only half of the leads required at the print head. This means that the width of the flat cable is also reduced to half. One lane 23' of the flat cable is guided towards the right out of the plug 20 round the right guide part 27 whilst the other lane 23" of the flat cable is guided towards the left side round the left guide part 28 at the plug 20.A cap 29 is placed on top of parts 20, 28, 27 and keeps the flat cable in touch to the two guide parts 28 and 27 so that the cables can move practically without friction relatively to the U-shaped bar 24 especially its free shanks 25, 26.

From Figure 3 the position ofthe plug 20 and the flat cable 23 may be seen in full lines when the print head takes up its left end position. In dotted lines, however, the position in which the plug 20 is to be seen when the print head takes up its right end position (Figure 1 dash-dotted lines). The two lanes 23' and 23" of the flat cable 23 are guided by another guide part 29 to another plug 30 which penetrates the bottom 24 of the U-shaped bar. The two ends of the flat cable 23 here are also spliced and are individually connected to the connecting points in the plug 30. Another plug 31 serves to introduce more leads to the printer leads which are not required in the print head but which serve for instance to drive the motor or the ink ribbon orfor moving the print head 6 relatively to the slide 5 etc.

Claims

1. A device for supplying current by means of a flexible flat cable from a base part to a print head arranged movable in front of a printing support, for instance to the printing magnets of a needle printer characterized in that a flat cable material is used which comprises only half of the required leads and that one lane (23', 23") of the flexible flat cable (23) each is led to the print head (6) from its two sides so that the introduction of the two lanes (23', 23") is effected in the middle between the end positions of the range of movement of the print head (6).

2. A device according to Claim 1, characterized in that the lanes (23', 23") are supported by a guide part (24).

3. A device according to Claims 1 and 2, characterized in that the guide part is a U-shaped bar (24) in which the two lanes (23', 23") are supported by the free shanks (25, 26) of the bar (24).

4. A device according to Claims 1 to 3, characterized in that in the bottom of the guide part (24) in the middle between the ends there is an introduction plug (30) to which the two lanes (23', 23") are connected.

5. A device according to Claims 1 to 4, characterized in that the base part (18) carrying the print head (6) is provided with a plug (20) to which the two lanes (23', 23") are led.

6. A device according to Claims 1 to 5, characterized in that the print head (6) is provided with a printed circuit plate (21) which connects the plug to the printing magnets.

7. A device substantially as described herein with reference to the accompanying drawings.