DE29818398U1 - Ribbon cassette with a ribbon guide for writing instruments - Google Patents

Description

p. mg. Friedrich Meier .... ...

Patent Attorney - European Patent Attorney J I · * · ··*·.£.··.

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Description

Ribbon cassette with a ribbon guide for writing instruments

The invention relates to a ribbon cassette with a continuous ribbon which is held in the printing area of a printer corresponding to a matrix dot matrix printer by a ribbon guide which encloses the ribbon and is assigned to the print head and moves with it.

Writing instruments with ink ribbons are equipped with ink ribbon cassettes to make changing the ink ribbon easier. With small ink ribbon cassettes that are carried along the print head along the print line, the ink ribbon is guided freely over a short distance so that when the cassette is changed, this section of ribbon finds the gap between the paper and the printing element when the cassette body is inserted into the designated holder.

In dot matrix printers in particular, the gap in which the needles must find the ribbon is very small. In these known designs, it cannot be ruled out that the ribbon will be compressed when changing, which can cause operational problems. If ribbon cassettes with a longer ribbon life are used, the cassette is connected to the frame of the writing instrument and the free ribbon section extends over more than the maximum possible line length. In order to guide the ribbon under the print head with the desired accuracy, the ribbon is guided on the print head in a slider that is carried along the line by the print head. This ribbon guide must be connected to the print head when the cassette is changed. To do this, the operator must establish or at least note the relative position of the ribbon guide and the print head. He must also position the guide correctly in the gap between the print head and the paper. If the ribbon guide is connected to the cassette via guide elements, e.g. a guide rod, this is done when the cassette is inserted into its holder. The operator must then pay attention to the positioning of the guide and the cassette at the same time. Inserting the ribbon requires practice and particular care. This is a source of interference that can endanger the operational reliability of the writing instrument.

The invention aims to largely eliminate this possible source of error by replacing the skill and care required to position the ribbon guide under the print head by hand with an automatic

working construction is replaced.

According to the invention, the stated object is achieved when using a ribbon cassette of the type described at the outset in that the ribbon guide is provided with preferably spring-elastic connecting elements, by means of which an operationally detachable coupling can be established, preferably during the printing gap adjustment, with parts of the print head for holding, guiding and moving.

To achieve a defined starting position, it is advantageous to arrange holding parts in the area of the ribbon outlet, which is usually arranged on protruding cassette arms, preferably molded into them, with which the detachable connecting elements of the ribbon guide come into engagement. This results in a defined parking position for the ribbon guide, which can be adopted and set down by parts of the print head, for example when positioning the print gap setting at the beginning or end of the print lines.

The invention is described and its mode of operation is explained with the aid of the drawing.

Fig. 1 shows a schematic elevation view of a portion of a ribbon cassette with a ribbon guide in the park position, as well as a print head also in a park position.

Fig. 2 shows a schematic plan view of the detachable connection of the ribbon guide with the cassette arms in the park position, as well as the connection with parts of the print head.

Fig. 3 and 4 show a print head with its connections to the ribbon guide in working position.

Identical parts are provided with the same reference symbols in all figures.

The print head, which is inserted into a holder of the writing instrument (not shown), consists of the magnetic drive 1 and the printing element, a needle body 2. The ribbon cassette consists of a container 3 which holds a continuous ribbon and to which arms 4, preferably foldable and U-shaped in cross-section, are attached at the side in the area of the ribbon outlet for guiding the ribbon 5. The arm 4 has contour parts 6 formed thereon which engage with clamp-like locking elements 7 of the ribbon guide 8.

The ribbon guide 8 has formed deflection parts 9 and 10, through which the ribbon 5 is enclosed and guided in the area of the printing opening 11. The printing opening 11 can be formed by the ribbon guide 8 itself, which is preferably made of plastic, or by a metallic, inserted sliding skid, which rests against the printing abutment 12 or the inserted paper.

A connecting plate 13 is attached to the print head 1 and is provided with openings 14 and 15. The pin-shaped connecting elements 16 and 17 of the ink ribbon guide 8 engage in these openings 14, 15. The print head 1 is detachably connected to the ink ribbon guide 8 by the pins 16, 17.

The connecting pin 16 consists of spring-loaded parts whose hook-shaped ends grip the edge of the opening 14 and thus form a connection to the print head that can be released in the direction of movement of the needles, i.e. perpendicular to the pressure abutment 12. The pin 17 ensures that the ribbon guide 8 and thus the print opening are in a parallel position with respect to the needle body 2. The pins 16, 17 allow a slight mobility of the ribbon guide 8 perpendicular to the paper plane.

By designing the openings 14 and 15 as elongated holes, the print head can be pivoted relative to the ribbon guide by a small angle of about 10° around the center of the printing element. See Fig. 2 in comparison with Fig. 4.

In order to prevent a tilting movement of the ribbon guide 8 relative to the pressure abutment 12, a support 18 is formed laterally in the area of the locking elements 7, which in the coupled state (Fig. 3) rests against a surface of the magnetic drive 1.

When delivered, the cassette arms 4 are folded in so that they rest against the cassette housing 3 to save space. The contour parts 6 formed on the outer end of the cassette arm 4 take up the clamp-like locking element 7 of the ribbon guide 8 and hold it. After folding out the cassette arms 4 and inserting the cassette into the writing instrument, the ribbon holder 8 comes into the parking position shown in Fig. 1. This so-called parking position usually also corresponds to the position of the print head for the necessary adjustment of the printing gap to the inserted paper thickness.

If the print head is now moved against the paper or the print abutment 12 when adjusting the print gap, the connecting pin 16 engages in the opening 14 of the connecting plate 13 and the pin 17 engages in the slot 15. As the print head moves in the printing direction, the print head releases the ribbon guide 8 from the locking element 6 and thus from the parking position via the connecting plate 13.

tion The ribbon guide 8 is thus part of the printing system and moves with it.

After completion of the printing process, the print head and the ribbon guide 8 are moved into the parking position shown in Fig. 1 and locked in place with the locking element 7 in the
Contour part 6 is held on the cassette arm 4. When the print head is pulled back, the pins 16 and 17 are pulled out of the elongated holes 14, 15 against the hold of the locking elements 6, 7 on the cassette arm, thus releasing the ribbon guide 8 so that the cassette can be removed from the printer.

Claims (8)

1. Ink ribbon cassette with a continuous ink ribbon which is held in the printing area of a printer corresponding to a matrix needle printer by an ink ribbon guide which encloses the ink ribbon and which is assigned to the print head and is moved with it, characterized in that the ink ribbon guide ( 8 ) is provided with preferably spring-elastic connecting elements ( 16 , 17 ) by means of which an operationally detachable connection, preferably during the printing gap adjustment, can be produced with parts ( 13 ) of the print head for holding, guiding and movement. 2. Ink ribbon cassette according to claim 1, characterized in that contour parts ( 6 ) are formed on projecting cassette arms ( 4 ) in the region of the ink ribbon outlet, which form a detachable holder with spring-elastic locking elements ( 7 ) of the ink ribbon guide ( 8 ). 3. Ribbon guide for a cassette according to claim 1 and 2, characterized in that the connecting elements ( 16 , 17 ) are arranged and designed axially parallel to the printing needles ( 2 ) in such a way that they lock with openings ( 14 , 15 ) on a connecting plate ( 13 ) on the print head during a printing gap adjustment movement. 4. Ribbon guide according to claim 3, characterized in that locking elements ( 7 ) are arranged, preferably molded, parallel to the printing movement direction, which form a detachable connection with contour parts ( 6 ) of the cassette for their parking position on the cassette. 5. Ribbon guide according to claim 4, characterized in that the locking elements ( 7 ) are designed as elastic snap parts, preferably molded on. 6. Ribbon guide according to claim 3 to 5, characterized in that the connecting elements ( 16 , 17 ) engage in slot-shaped openings ( 15 , 16 ) of a connecting plate ( 13 ) assigned to the print head in such a way that the print head can be pivoted by a few angular degrees. 7. Ribbon guide according to claim 3 to 8, characterized in that at least the connecting elements ( 16 , 17 ) are formed from spring-elastic material. 8. Ribbon guide according to claims 3 to 7, characterized in that a guide support ( 18 ) is arranged on at least one side of the print head.