RU2231448C2 - Vibration-type dot line printing head - Google Patents

Abstract

FIELD: printing heads of printers on paper media, in particular, cash registers and other loggers.

SUBSTANCE: the head has a body, permanent magnet, magnetic core, compensation coils with cores, unit of springs-hammers, each having a dot printing area located on its top, and the root is branched into two parts turned to the top, the turned parts of the adjacent springs are integrated and have holes for attachment to the body. A tab of soft magnetic material is fastened to the permanent magnet in the area of each core on the side of one of the poles, the tab end is bent to the opposite pole of the permanent magnet to the position at which the magnetic flux in the cores of all section is the same and minimum for operation of the spring-hammers.

EFFECT: reduced strength of current in the compensation coils due to equalization of the magnetic fluxes in the cores to the position of the "weak" section, and reduced power consumption.

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Description

The invention relates to the field of print heads for printing devices that output information on paper, in particular cash registers and other recording devices.

The print head is the main node of the printing mechanism, converting the incoming electrical signals into a print of points from which the desired character or image is synthesized.

The point-by-line dot-type printing head of an oscillatory type has a plurality of percussion elements arranged in a single row along the printed line with step t, and oscillating along the line within step t.

The present invention relates to printheads of a releasing type in which the impact force in the print direction is determined by the elastic force of a flat spring equipped with an impact element held (locked) in a stressed state by a permanent magnet. Release (release) of the spring from the stress state to strike is carried out by applying an electric current pulse to the compensation coil located on the magnetic circuit section in which the magnetic flux is induced, which neutralizes the initial magnetic flux from the permanent magnet.

Known print head according to US patent No. 5219235, MK 41 B 2/245, containing a housing, a permanent magnet attached to it by one pole, a yoke with cores to the other magnet pole, a front wall, a block of hammer springs with anchors located against the cores , and shock elements, compensation coils, worn on the cores.

Known print head according to A.S. USSR No. 1482820, MKI B 41 J 3/12, which is closest to the claimed invention.

The prototype print head contains a housing, a permanent magnet attached to it by one pole, a yoke with cores, a front wall and a block of hammer springs with shock elements attached to the other pole of the magnet.

Each spring has a root, branched into two parts, which are turned to the top of the spring, and the rotated parts of adjacent springs are connected in one piece. Holes are made at the junction points for attaching the hammer-spring unit to the head housing. Compensation coils are put on the cores. Each print head can be conditionally divided into sections according to the number of hammer springs with percussion elements. Moreover, each section has an individual part, for example, a flat hammer spring, an anchor attached to the spring, a core, a compensation coil, a working gap and a common part including a permanent magnet, a housing and a yoke that attaches individual cores to the permanent magnet. Each section has its own individual magnetic circuit, including a core passing inside the compensation coil, an anchor attached to the spring, a working gap, a part of the permanent magnet, part of the yoke and part of the body. An individual magnetic flux passes through each individual magnetic circuit, the magnitude of which in different sections will be different. In some sections having favorable conditions for magnetic conductivity, it will be more, in sections with lower magnetic conductivity it will be less. The magnetic conductivity of the magnetic circuit is influenced by both structural factors associated with various passage sections of the housing elements, as well as technological factors associated with manufacturing errors. A permanent magnet common to the entire head may have spotting magnetic properties over the area of contact with the body and yoke. Due to the different magnetic fluxes in the sections, the force holding the spring in tension will be different in different sections. Consequently, the optimal magnitude of the current pulse supplied to the compensation coils will be different in different sections. A section that is “strong” in magnetic flux will require a larger current pulse, while a “weak” section will require less. For guaranteed operation of all sections, current pulses must be supplied to the head, taking into account the "strong" section, therefore, the "weak" sections will work with an excess of electrical energy that is unproductive for heating the compensation coils. This is a drawback of the above print heads.

The aim of the invention is to eliminate this drawback, i.e. reduction of energy losses.

This goal is achieved by the fact that in the zone of each core to the permanent magnet on the side of one of the poles is attached a tab of magnetically soft material, the end of which is bent to the opposite pole of the permanent magnet to a position where the magnetic flux in the cores of all sections is the same and optimal for spring hammers.

Figure 1 shows a cross section of the head, figure 2 is a front view.

The print head consists of a block of hammer springs 1 with anchors 2 and percussion elements 3 (the head can have several blocks of hammer springs located in series with the first along the printing line to expand the print area), front wall 4, body 5, permanent magnet 6, block of cores 7, compensation coils 8 and reeds 9.

The print head is arranged in two non-separable assemblies: a housing assembly including a permanent magnet 6, a core block 7, compensation coils 8 and a housing 5, and a printing assembly including a front wall 4, a spring-hammer block. These two nodes are fastened together in the plane "B" (figure 1) only by the forces of magnetic attraction of a permanent magnet.

The head works as follows. In the initial position, the spring-hammer of each section is cocked due to the attraction of the armature 2 under the action of the magnetic flux F1 generated by the permanent magnet 6. The direction of the magnetic flux F1 is shown by arrows from the permanent magnet 6 through the core 7, the working annular gap "b", joint B "and further branches through the front wall 4, through the upper and lower shelves of the housing 5 to the opposite pole of the magnet 6. Such a distribution of magnetic flux will be in conditionally" weak "sections. In these sections, the tongue 9 will not be bent. In conditionally “strong” sections, part of the magnetic flux Ф2 generated by the permanent magnet 6, through the bent tab 9 will branch (close) to the opposite pole of the permanent magnet. Moreover, the “stronger” the section, the more the tongue will be bent to the opposite pole. Thus, the main flow in the core 7 decreases to a value commensurate with the flow in the “weak” section.

When a current pulse is applied to the compensation coil 8, an electromagnetic flow with an opposite direction is formed in the core 7. The magnetic flux F1 in the core decreases sharply, the anchor 2 is released and under the action of the spring 1 rushes to the anvil 10 and the impact element 3 strikes through the ink ribbon on a paper tape. Upon completion of the current pulse, the armature 2 under the influence of magnetic flux F1 returns the spring to its original position and blocks it in a stressed state.

Claims (1)

The point-by-line dot printing head of an oscillatory type, comprising a housing, a permanent magnet, a magnetic circuit, compensation coils with cores, a block of hammer springs, each of which has a dot-type printing element located on its top, and the root is branched into two parts, turned to the top, and the rotated parts of adjacent springs are connected integrally and have holes for attachment to the housing, in the area of each core to the permanent magnet from one of the poles is attached a tongue of soft magnetic material and the end of which is folded to the opposite pole of the permanent magnet to a position in which the magnetic flux in the cores is the same for all sections of the hammer actuation-springs.

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