DE3507782A1 - BRACKET FOR A THERMAL PRINT HEAD - Google Patents

Description

TER MEER - MÜLLER ■ STEiNMEISTER ':' - ■ ' ' - '- "Saints - PW-p 490

- - 36U7782

description

Holder for a thermal printhead

The invention relates to a holder according to the preamble of claim 1 for support and guidance of a thermal printhead in the drive of a thermal printer and / or thermal recorder.

At. Thermal printers or registrars of the type mentioned the thermal print head (hereinafter "thermal head") is on an axis in the drive of the printer (recorder) so out that the juxtaposed in a row thermal printing elements or heating points against the paper web press, which on its back by a rubber-coated, at the same time acting as a counter-pressure roller Transport roller is supported. In order to get a clean typeface, the heating points must have a certain Pressing force must be pressed evenly against the paper. This sets one across the length of the row of heating points very even pressure on the one hand and a very precise, axially parallel alignment of the bearing axis of the bracket the thermal head and the shaft of the transport roller on the other hand, as well as a very precise feeding of the paper web in advance. The thermal head must therefore be very precise during manufacture, but also after every cleaning or renewal adjusted. If these requirements are not met, the result is an uneven typeface or the trace of a written curve is imaged unevenly sharp.

TER MEER · MÜLLER ■ STEINMEISTFR .- Hellige - PW-P 490

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The invention is therefore based on the object to improve thermal printer (thermal register) so that at A consistently uniform typeface is achieved with the least possible manufacturing and assembly effort. 5

The solution according to the invention consists in a holder for supporting and guiding a thermal print head in the drive of a thermal printer or register according to type mentioned in the implementation of the characterizing features of claim 1.

Advantageous further developments of the inventive concept are specified in subclaims.

The idea of the invention goes to the holder of the thermal print head s not rigid relative to the drive, but rather flexible due to a bearing that is slightly movable to apply, but in such a way that when a pressure force is applied over the entire length of the row of heating points even pressure against the paper web is achieved.

The invention and advantageous details are described below in an exemplary manner with reference to the drawing Embodiment explained in more detail. It show: 25

Fig. La is the side view of a thermal head holder

with features according to the invention, seen from the

Side of the transport roller, and

Fig. Ib shows the partial sectional side view of the thermal head holder according to Fig. la-

The thermal head 6 in the form of a not shown in detail The ceramic plate fitted with the heating points and the corresponding control logic is coated with a heat-resistant adhesive at the support points marked with "x" on a holding

TER SEA. MÜLLER ■ STEINMEtSTER

Saints - PW-P 490

Plate 3 made of glass fiber reinforced thermoplastic material glued on, with for precise positioning Serve stops 3d, the parallel to groove-like guides 13 with stop surfaces 3b, 3c in lateral webs 9 of the Holding plate 3 are made. The thermal head 6 is to be described in more detail below via the holder 3 Way pressed against a paper web 8 in the area of its heating points, the back side by a rubber-coated Transport roller 7 is guided and supported, which can also be referred to as a counter-pressure roller. The transport roller 7 is driven by a motor, not shown. So it forms the counter-bearing for the individual, heating points 11 of the thermal head 6 arranged close to one another in a row. Die.Heizpunkte 11 must be pressed evenly against the paper web 8 with a certain force. this is achieved according to the invention in that the holding plate 3 in the setting direction against the paper web 8 in only one Support point of a knob-like protruding approach 3a in the middle between the two groove-like guides 13 rests on the axle 4 mounted in the frame of the drive, which is not shown in detail. That is, the bottom of the groove of the guides 13 does not normally touch the axis 4. The holding plate 3 is on the one hand in the vertical direction the illustration only in the area of the stop surfaces 3b, 3c of the guides 13 and in the horizontal or adjustment direction supported only at the support point of the approach 3a. The pressure force and its even distribution on the through single-point support so to speak "floating" over the Holding plate 3 held thermal head 6 is achieved by a leaf spring 2, which in the area between the point-like Support of the holding plate 3 by the approach 3a and the stops 3d on the thermal head 6 facing away Outside of the holding plate is clamped on one side and at its free (distal) end either on the frame of the Drive is applied or - if the contact pressure is adjustable

¹ UCTED

TERMEER-MOLLER-STEINMEISTrR-- ..Holy PWP 490

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should be - can be adjusted in their pressing force by means of a screw 1 anchored in the frame. Of the by two rays 14, 15 emanating from the point of support on extension 3a, this angle area roughly defines the effective area the adjustment force by the leaf spring 2.

The transport roller 7 and the axis 4 must be manufactured lying parallel, which is achieved, for example, in this way is that the same frame board is used in production. Assuming the usual manufacturing tolerances an adjustment of the parallelism of the thermal head 6 and the transport roller 7 is not necessary for such writing units more required.

Reference 5 denotes a connector 5, which can also serve as a transport lock and is removed when the mounting plate with the thermal head 6 is to be removed from the top. This can be done in a simple manner e.g. B. at occasional cleaning beneficial. Readjustment when changing the thermal head is no longer necessary. Reference 12 indicates the encapsulated integrated circuits of the control logic. At 16 it's a multi-core Flat ribbon cable, via which the power supply and the supply of the control signals for the control logic he follows.

Another advantage is that there are multiple thermal heads e can be arranged next to each other, with each individual thermal head automatically following the transport roller 7 aligns. If - as shown in the drawings - the holding plate 3 is narrower than the thermal head 6, so several thermal heads can be arranged without a gap. This allows a curve to be drawn over several thermal combs Write without gaps with a thermal recorder.

Claims (4)

TER MEER-MÜLLER-STEINMEISTER PATENTANWÄLTE - EUROPEAN PATENT ATTORNEYS Dipl.-Chem. Dr. N. tar Meer Dipl.-Ing. H. Steinmeister Mai ipv * l / -i TvViiayG + "y 4 R / nrtUr-L9Q © D © CK" "wtr3SSÖ Ol D-8OOO MUNICH 80 D-48OO BIELEFELD 1 Mü / cb PW-P 490 March 05, 1985 HELLIGE GMBH Heinrich-von-Stephan-Straße 4 D - 7800 Freiburg im Breisgau Bracket for a thermal print head Patent claims 1. Bracket for supporting and guiding a thermal printhead (6) in the drive of a thermal printer and / or thermal recorder, its in a row next to each other arranged thermal printing elements pivotably mounted on an axis (4) supported in the frame of the drive Holding plate (3) against a paper web (8) supported on the underside by a driven transport roller (7) are employed with light pressure, characterized in that - the retaining plate (3) on two perpendicular to the axis (4) end webs (9) each one the axis (4) TER MEER · MÜLLER ■ STEtNMEISTFR - .. ^: - Saints - PW-P 490 supporting stop surface (3b, 3c) and a centrally located, protruding from the inner surface of the holding plate (3) opposite the thermal print head (6), on the axis (4) aligned approach (3a) which provides a point-like support for the Forms retaining plate (3) on the axis (4), and that - in the area between the projection (3a) and the row of Thermal printing elements (11) on the outside of the holding plate (3) facing away from the thermal head (6), a pressure spring (2), the other end of which is supported in the frame of the drive. 2. Holder according to claim 1, characterized in that the spring is a leaf spring (2) on the outside of the Holding plate (3) clamped on one side is fixed (at 26), and its spring pressure force on the holding plate (3) can be adjusted by an adjusting screw (1) which acts on its distal end (2a) and is mounted in the frame. 20th 3. Holder according to one of the preceding claims, characterized in that the The thermal head (6) is rigidly connected to the holding plate (3), in particular by gluing. 4. Holder according to one of the preceding claims, characterized in that the holding plate (3) is narrower than the width dimension of the thermal printhead (6).