EP0045360A2 - Type band for a band printer - Google Patents

Abstract

1. Type belt for type belt printer, characterized in that the type belt (1) is coated with a synthetic material (12).

Description

The invention relates to a type tape for a type tape printer.

Usual type tape printers (e.g. the IBM type tape printer 3288, 3289) have an all-round type tape, which presents itself as a steel tape with raised print types and tact marks etched out by photochemical means.

The following arrangement of the steel strip in relation to a pressure abutment and the record carrier and ink ribbon to be considered is decisive for the printing of a character: The smooth back of the steel strip moves past the pressure abutment. The ribbon and the recording medium are located in front of the front of the ribbon with the raised printing types. The character imprint in a certain printing position is effected by a printing hammer, which strikes the recording medium and presses it against the ink ribbon, the type of steel ribbon to be printed and the platen.

One of the biggest problems with steel band printers, which has only been partially solved so far, lies in the heavy use of the ink ribbon by the sharp-edged printing types of the steel ribbon, which leads to the soon destruction and uselessness of the ink ribbon.

This disadvantage could only be kept inconspicuous with low printing capacities,

In order to increase the printing performance, efforts were made to reduce the destructive influence of the sharp-edged printing types on the ink ribbon in that the front side of the ribbon subjected to a polishing process. Character tapes of this type with a polished front have been / are used in type tape printers, e.g. B. of the type IBM 3262 used. The reduction in the destructive force of the previously sharp type edges on the ink sheet is due to the fact that the type edges are slightly rounded by the polishing process. 1

Such a polishing process turns out to be very complex and expensive and is also very difficult to control. In other words: the polishing process often does not lead to the desired result.

To avoid these disadvantages, it is an object of the invention to provide a type tape in which the destruction of the ribbon fabric due to the sharp type edges is enormously reduced and which is easy and controllable to manufacture.

This object of the invention is achieved by the measures mentioned in the characterizing part of claim 1.

Further advantageous embodiments of the invention can be found in the subclaims.

An embodiment of the invention is shown in the drawings and will be described in more detail below.

• Fig. 1. eine schematische Schnittdarstellung eines zwischen einem Druckwiderlager und einem Druckhammer angeordneten Typenbandes, eines Farbbandes und eines Aufzeichnungsträgers;
• Fig. 2 eine perspektivische Teilansichst der Vorderseite eines Typenbandes mit erhaben herausgeätzten Drucktypen und Taktmarken;
• Fig. 3 eine schematische Schnittansicht durch ein Typenband gemäß der Schnittlinie A-A in Fig. 2;
• Fig. 4 eine schematische Schnittansicht durch ein Typenband mit einer Kunststoffbeschichtung vor Ingebrauchnahme Fig. 4A und Fig. 4B nach Ingebrauchnahme.

Show it:

• Figure 1 is a schematic sectional view of a type ribbon, an ink ribbon and a recording medium arranged between a pressure abutment and a printing hammer.
• 2 shows a perspective partial view of the front of a type tape with raised etched out printing types and timing marks;
• 3 shows a schematic sectional view through a type strip according to section line AA in FIG. 2;
• Fig. 4 is a schematic sectional view through a type tape with a plastic coating before use. Fig. 4A and Fig. 4B after use.

In Fig. 1 is shown in a sectional view how the type tape 1 is arranged opposite the platen 2, the ink sheet 3 and the recording medium 4 and the print hammer 5. To generate a character print, the hammer 5 strikes against the recording medium 4, the ink ribbon 3, the raised etched print type 6 on the front side 1-1 of the type tape 1 and presses the type tape 1 with its rear side 1-2 against the pressure abutment 6. This results in an imprint of type 6 on the recording medium 4. During the imprint, the type ribbon 1 moves in the direction perpendicular to the plane of the drawing, while the ink ribbon 4 remains relatively stationary. At the moment of printing, there is a strong lateral stress on the ribbon, caused by the sharp printing type edges of the character 6. This stress can ultimately lead to destruction of the ribbon tissue, so that - as already indicated - when using "untreated" type ribbons, the ribbons must be replaced frequently.

In Fig. 2 is a partial perspective view of the front 1-1 of the type tape with raised etched out types (6-1, 6-2) and timing marks (6-1-1, 6-2-2) are shown. Excerpts of types H (6-1) and I (6-2) can be seen on the front 1-1 of volume 1. The timing marks assigned to these printing types (6-1-1 and 6-2-2) are also etched out. They are used to synchronize the pressure control.

FIG. 3 shows a sectional illustration of the type tape along the section line A-A according to FIG. 2. It can be seen that the type and timing mark edges (7) are extremely angular, which ultimately has a destructive effect on the ink ribbon (this sharpness of the printing types naturally also applies to the cutting direction indicated in FIG.

The destructive influence of the sharp type and clock mark edges is now avoided in that the drawing tape is coated with a plastic, preferably with a material containing polytetrafluoroethylene (PTFE). PTFE is e.g. B. known under the trade name "TEFLON" from Dupont.

From a technological point of view, such a coating is no longer a problem. However, such coatings have hitherto only been carried out for flat parts, in order, for example, _B. to prevent food from sticking to frying pans or saucepans or to achieve a certain lubricating effect with parts sliding past one another (carburettor bearings in automobiles).

_D ate a coating of irregular relief-like type belt surface with sublime etched-out type and the timing marks to making desired satisfaction of tasks could lead itself was held by specialists to be impossible and doubts.

4 A and B show schematic sectional representations of a type tape before and after use, which has been coated with a PTFE-containing material. The section line would correspond to B-B of FIG. 2 if the type tape shown there had been coated.

The metallic cut surface is heavily hatched, while the cut surface is only slightly hatched by the layer 12 containing PTFE.

Immediately after the coating, the PTFE-containing material is not only deposited on the locations 8 between the type elevations 6-1 and clock mark elevations 6-2, but also at locations 9 on the type surface to be printed, as well as embankment-like at locations 10 on both sides of the types - or time stamp surveys.

After the use of type tape 1, the material containing PTFE deposited in the areas 9 is rubbed off in the shortest possible time (with high printing performance after a few cycles); it also partially attaches to the embankments 11 (FIG. 4B). From this representation it can be seen that, compared to the representation according to FIG. 3, the effective type and clock mark edges are no longer so sharply formed (embedded in material containing PTFE) and therefore can no longer have such a destructive effect on the ribbon fabric.

The PTFE-containing layer must also contain certain additives (resins) that guarantee the abrasion resistance of the layer. Such admixtures for achieving a higher abrasion resistance are commercially available (eg as "TEFLON S", registered trademark of the Dupont company). The application of pure PTFE required e.g. B. for reasons of liability on the base material before outgoing sandblasting and a high temperature. However, both of these boundary conditions would not be acceptable, particularly for type bands. In the case of steel ribbons for type ribbon printers, the layer containing PTFE is applied by spraying with a subsequent moderate heat treatment.

As a result of the surface tension of the sprayed PTFE emulsion containing result - as well as from Figures _4A and 4B seen -. On the flanks of type plate or clock m _a rkenerhebungen ramped flail-like contours, favoring the passage of sliding of the type band on the ribbon g _s . Lateral carry-over of the ribbon is enormously reduced compared to an uncoated, but polished type ribbon. As a result of the coating, the mechanical destruction of the ribbon fabric is reduced to _{such an} extent _that the service life of the ribbon is at least doubled for new type ribbons.

Furthermore, the contamination occurring in the area of the type tape is reduced, since fewer type fibers and colored particles are entrained by the type tape in coated type tapes and are only transported to a small extent due to the anti-adhesive properties of the layer surface.

During a period insert coated type bands (after several million lines), and of course an overall _r ingfügiges removal takes place of the PTFE-containing layer. DC _z eitig with this removal takes place but also a Verrun- _d ung the Type tag or clock mark edge, so that one color does not occur t _u chzerstörende effect as it would be in an uncoated polished band and from the beginning of the case.

The coating on the front of the type tape also leads to a reduction in wear on the surface of the type tape, which is due to the formation of a thin film of the PTFE, which is also to be understood as a dry lubricant, both on the type surfaces to be printed and on the fabric of the ink sheet.

The use of a PTFE-containing layer for the relief-like type tape surface, taking into account the particular type of stress that occurs with impact printers, led to the surprising result that the destructive influence of the formerly sharp type and clock mark edges on the ink cloth fabric could be reduced enormously.

Furthermore, during the partial abrasion of the PTFE-containing layer, after several million print lines, there is a gradual, ribbon-friendly rounding off of the type or clock mark edges, as could not be achieved by a polishing process that is difficult to control. As a result, the destructive influence of sharp-edged print type and timing mark edges on the ink blanket is never given when a coated type tape is used.

Claims (3)

1. Type tape for type tape printer,
characterized,
that the type tape (1) is coated with a plastic (12). 2. Arrangement according to claim 1,
characterized,
that the layer material contains polytetrafluoroethylene (PTFE). 3. Arrangements according to claim 1 or 2,
characterized,
that the type tape (1) with the printing types (6) protruding on it (1) in a manner known per se is loaded with layer material (12) of such a thickness,
that the layer material is arranged like a slope (11) towards the edge of the printing type surface to form a slope crown.

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