JPH0250871B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for leaving no trace of text on single-use ink ribbons for typewriters and the like.

It is well known that written text remains clearly visible on such ink ribbons.
On the one hand, visibility is caused by the application of ink particles corresponding to the selected characters during the printing process.
On the other hand, the text can also be read when the remaining ink particles are removed from the ink ribbon. This is therefore because the characters of the type bar leave an impression on the ink ribbon, so that the written text remains clearly legible.

In particular, government offices, notaries' offices, public prosecutor's offices, etc. constantly have the requirement to prevent written texts from being able to be read by outsiders on the ink ribbon of a typewriter. This requirement exists as long as the operator is instructed a few times to remove the ink ribbon cassette from the typewriter and store it in a safe before leaving the office, for example in the evening or on weekends.

A method and a device for erasing text on typewriter ink ribbons are known from German Patent Application No. P 31 35 897.7-27. However, this method is only suitable for used ink ribbons. The request to erase the written text on a ribbon that is only partially used cannot be fulfilled.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a device which makes it possible to erase the text visible on the ink ribbon as soon as possible after printing in a typewriter, printing device, etc., so that it is impossible to identify the text. shall be.

Claim 1 describes an apparatus for solving the above problem. While the ink ribbon passes between the rollers, the protrusion forces a - into the ink ribbon, thereby erasing the characters.

Embodiments of the present invention will be described in detail based on the drawings.

Reference numeral 1 designates an ink ribbon, which is composed of a layer of synthetic resin foil and removable ink particles in a known manner. As is clear from the figure, character 2 can be clearly read. According to the device according to the invention, the ink ribbon 1 is provided with a large number of small, closely spaced deformations 3, the deformations making it impossible to read the characters 2. Another partial ink application also occurs in the deformation 3.

FIG. 3 shows two rollers 4 and 5 with axes 6 and 7. The roller 4 has a projection 8 formed in the shape of a papilla. In the embodiment shown, the projections 8 are distributed evenly around the roller 4 in axial rows. The protrusions 8 in one row are arranged in axial displacement with respect to one adjacent row.
As a result, a grid of fine deformations 3 is created in the ink ribbon 1.

The roller 5 follows the same grid of protrusions 8 into the recesses 9
ink ribbon 1 when it is fed between opposed spring-loaded rollers 4 and 5.
is pushed into the recess. By means of shafts 6 and 7 rollers 4 and 5 can be rotatably supported.

According to FIG. 4, the projection 8 can be designed in the form of a barb.

The tips of the protrusions pierce the plastic foil of the ink ribbon 1 during deformation, thereby eliminating mechanical strains in the material, so that spring backs of the deformation section 3 are avoided.

From the above, both rollers 4 and 5 can be removed in a simple manner.
The mechanical action on the ink ribbon 1 is caused by the character 2
is no longer read. At that time, roller 4
It is not important where and 5 are located.

According to FIG. 5, rollers 4 and 5 are rotatably and drivably mounted in an ink ribbon cassette 10. Ink ribbon 1 is rewinding spool 11
and is wound onto the take-up spool 12. Printing location A between arms 13 of cassette 10
The ink ribbon 1 passes through. After reloading the cassette 10, the ink ribbon 1 is guided between the driveable rollers 4 and 5, and a corresponding erasing action is carried out by the device according to the invention.

In the embodiment according to FIG. 6, rollers 4 and 5 are arranged in a typewriter, printing device or similar machine. At this time, the housing 1 is placed on a plate 14 used as a support for the ink ribbon cassette 15.
6 is arranged, and the housing can be closed in an expedient manner by means of a cover, not shown.
The roller 5 is rotatably supported in the housing 16. The roller 4 is supported by a projection 8 on a lever 17 which is pivotably supported on an axle 18 and is under the action of a spring 19. A spring presses both rollers 4 and 5 together. The roller 5 is drivable in the embodiment shown. A belt 20 can be used for this purpose, which retains its drive by the ink ribbon feeder. It is of course provided that the drive of the rollers 4 and 5 is synchronous with the drive of the take-up spool 21 in the ink ribbon cassette 15. For example, rollers 4 and 5
and the formation of undesirable loops of the ink ribbon 1 between the take-up spool 21 can be avoided.

The ink ribbon runs from the unwinding spool 22 to the printing location A and then exits the ink ribbon cassette 15 again and is guided into the housing 16.
It must then be guided around the deflection section 23 and between the two rollers 4 and 5. For this purpose, roller 4 can be lifted off roller 5 against the action of spring 19. Then ink ribbon 1
The ink ribbon 1 is returned to the ink ribbon cassette 15 again so that it can be taken up on the take-up spool 21.

As is common in typewriters and the like, the ink ribbon 1 is moved toward the take-up spools 12, 21 by a predetermined amount each time a character 2 is printed. The character 2 thereby reaches between the short sections of the rollers 4 and 5 after the printing point A, where the deformation of the ink ribbon 1 is carried out by the pressing of the projections in the direction opposite to the direction of the printing pressure, resulting in a zigzag pattern. will be deleted. If necessary, use rollers 4 and 5 to erase sentences that should not be erased.
After the printing of the text which is to be kept secret in order to be conveyed to the rear of the print position, a few extraneous characters 2 can be printed after the printing location. It appears that the rollers 4 and 5 should be arranged as close as possible to the printing location A in order to achieve the best possible utilization of the ink ribbon 1. The housing 16 should be as sealable as possible; in order to avoid that, during mechanical deformation of the ink ribbon, ink particles fall into the interior of the typewriter, for example, and cause dirt or malfunctions there.

A device similar to that described in FIG. 6 can also be provided in typewriters in which the ink ribbon 1 is used wound on removable spools rather than in cassettes 10, 15. It is conceivable there for rollers 4 and 5 to additionally take on the function of transport rollers for ink ribbon 1.

West German patent application specification stated at the beginning of the specification
In accordance with the task according to P3135897.7-27, rollers 4 and 5 can also be arranged in a separate housing, where the rollers are driven by a motor. Of course, the erasure of the text contained on the ink ribbon 1 then only takes place after the ink ribbon 1 has been completely used.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of a part of the ink ribbon after printing, FIG. 2 is a sectional view of the ink ribbon after erasing by the device according to the invention, FIG. 3 is a roller pair, and FIG. 4 is another embodiment. A partial front view of the roller according to the example, FIG.
The figure shows the arrangement of the device, for example in a typewriter, alongside an ink ribbon cassette. Codes in the figure, 1... Ink ribbon, 2... Characters,
4, 5...Device, A...Printing location.

Claims (1)

[Scope of Claims] 1. A device for erasing text on a one-time use ink ribbon for typewriters, etc., in which the ink ribbon is machined in such a way that the text is no longer recognized after passing the printing location. In the device for erasing the above-mentioned text, which is fed into a device which is deformed by the action of one of the rollers 4 has a protrusion 8 that pierces the ink ribbon, and the other 5 has a corresponding recess 9
An erasing device characterized in that the rollers 4 and 5 are disposed inside the ink ribbon cassette 10. 2. The apparatus according to claim 1, wherein the ink ribbon 1 is deformed by pressing the protrusion 8 in a direction opposite to the printing direction of the text 2 to form a zigzag shape. 3. The device according to claim 1, wherein the protrusion 8 is formed in the shape of a papilla. 4. The device according to claim 1, wherein the protrusion 8 is formed in the shape of a barbed piece.