Patent GB-1061825-A (GB)
Title: Improvements in or relating to methods of applying coloured bands to electrical conductors
IPC: B05B5/08
Filed: 1965-06-11
Abstract: 1,061,825. Coated electrical conductors. INTERNATIONAL STANDARD ELECTRIC CORPORATION. June 11, 1965 [June 12, 1964], No. 24749/65. Heading B2K. [Also in Division D1] An elongated electrical conductor has a succession of coloured bands applied thereto by moving the conductor longitudinally through a surrounding electrode structure, feeding a vapourized colouring material into the space surrounded by said structure, and applying a series of voltage pulses to produce potential differences between the conductor and an electrode of the electrode structure, wherein at least some of the potential differences are of sufficient amplitude to cause electrostatic precipitation of particles of the colouring material on the surface of the conductor. The electrode 4 may be provided with a set of radially inward pointing spikes 5 disposed in a ring inside the structure. The interval between successive pulses may be adjustable whereby for a given rate of movement of the conductor the spacing between successive coloured marking rings may be controlled. The voltage pulses may be of substantially rectangular wave form. The duration of the voltage pulses may be equal to or less than the interval between successive pulses. The electrode structure may comprise a plurality of co-axial electrodes each at an equal distance from the next the electrodes being joined to one another in a tubular fashion whereby the thickness of a coloured band caused to be deposited by a first one of the electrodes when subjected to one of the voltage pulses may be enhanced by a further precipitation of particles of the colouring material under the influence of a second electrode when subjected to a later voltage pulse. The distance between adjacent electrodes may be equal to the distance between adjacent coloured bands to be applied and wherein adjacent electrodes are subjected to pulses simultaneously. Adjacent electrodes may be electrically connected together. The step of feeding a vapourized colouring material into the space may be effected by feeding the vapour into the structure in a direction paraxial therewith or by feeding the vapour to the or each electrode through at least one aperture in (at 13) or closely adjacent to (at 14) the electrode. The pulses may be superimposed upon a unidirectional voltage which may be of mutually opposite polarities. The electrode structure may comprise a mask 7 interposed between the electrodes 5 and the conductor 1. The mask comprising tube sections held coaxially with the conductor and apart from one another to provide gaps between adjacent tube sections, and wherein each of the gaps has an axial length about equal to the axial length of the coloured bands and is in alignment with an electrode. The mask may be of an electrically insulating material e.g. polytetra fluoro ethylene, or of an electrically conductive material, which may be charged to a potential of a polarity opposite to the polarity of the charge on the particles of colouring material. A controllable unidirectional voltage may be applied between the conductor and the electrodes, and a pulsating voltage applied to the mask, whereby the masks acts as an electrostatic control element in the path of the particles of colouring material. The conductor may be bare or covered with insulating material e.g. a vinyl polymer or a polyolefin.