EP0018311A1 - Electronically controlled printing mechanism - Google Patents

Abstract

1. Electronically controlled printing mechanism of modular design for either manually or mechanically fed papers, characterized by the following components : a) a basic module consisting of a desk (3), two friction rollers (6) for feeding the paper, a toothed belt (7) which drives them and which is driven by a large wheel (8) via a pinion (9) by means of an electric motor (10), counter rollers (12) for pressing the paper against the two friction rollers (6), a light barrier (14) arranged at one end of the paper track (4) for generating a pulse to start the feeding of the paper when the paper is fed manually from this end, and a second light barrier (15) for generating pulses for the print and control timing which are triggered when the toothed wheel rim of the large wheel (8) passes through the light barrier (15) so that one pulse per column of a needle character and/or per bit of the magnetic type can be picked up at the toothed wheel rim of the gear wheel (8) for the paper transport, and that the number of teeth on the large wheel (8) is selected such that one tooth corresponds to one column of a needle character or to one bit of the magnetic type, respectively ; b) a supplementary module to enable conversion from the longitudinal type to the transverse type process, consisting of a threaded spindle (16) mounted vertically in relation to the paper feeding device for moving a carriage carrying the printing heads (1 and 13, respectively) along the spindle, a rod (17) for guiding this carriage, a large wheel (18) which drives the threaded spindle (16) via a pinion (19) and via an electric motor (20), and a light barrier (21) for generating pulses for the print and control timing which is effected by means of pulses which are triggered when the toothed wheel rim of the large wheel (18) passes through the light barrier (21), with the number of teeth on the large wheel (18) in combination with the pitch of the threaded spindle (16) being selected such that, as in the case of the basic module according to a), one tooth corresponds to one column of a needle character or to one bit of the magnetic type, respectively ; c) a supplementary module consisting of a printing head (13) mounted on the desk (3) for machine-readable type and/or an electronically controlled printing head (1) arranged above the desk (3) for visually-readable type with a ribbon cartridge (2) and a motor, with the printing head (1) for visually-readable type being swivable through 90 degrees at the carriage for conversion from the longitudinal type to the transverse type process, and the control leads for the motors (10, 20) and the light barriers (15, 21) being exchangeable to enable use of the same print program ; d) a supplementary module for mechanical paper feed from the other end of the paper track (4) opposite the light barrier (14), consisting of a third friction roller (6), a wedge member (11) serving as one longitudinal side of the paper feed channel (5), a rocker (22) mounted longitudinally along the other side of the channel, with a brake shoe (26) pressable against the wedge member (11) to clamp the paper, and with a counter roller (23), with the rocker (22), when caused to swivel by an actuating magnet (24), pressing the counter roller (23) against the friction roller (6) to activate the paper feed from this end of the paper track and moving the brake shoe (26) away from the wedge member (11) so that the paper is freely movable through the feeding channel (5), and a pulse-controlled cutting device (30-35) provided at the opposite end of the paper track (4) adjacent to the light barrier (14) ; e) a supplementary module located adjacent to the supplementary module according to d) for generating pulses for proper form synchronization, consisting of a light rod (27) and a phototransistor (28) which scans form sheets provided with control apertures and provides corresponding synchronization pulses.

Description

The invention relates to an electronically controlled writing mechanism in a modular design according to the preamble of claim 1.

Writing mechanisms for visually and / or machine-readable writing are already known, furthermore, writing mechanisms for manually pre-inserted fined forms or for automatically transported continuous paper, writing mechanisms for one or more retrievable paper formats, writing mechanisms for form-independent or form-correct printing as well as writing mechanisms for longitudinal or that Cross-scripting process. It is also already known to control these writing mechanisms electronically. All of these writing mechanisms are designed in a wide variety of combinations. But so far there is no writing mechanism that combines all of the above-mentioned requirements.

The task is therefore to create a writing mechanism that is electronically controllable and that is modularly constructed so that it can be used both for visually and / or machine-readable fonts, for manually inserted individual forms or for automatically transported continuous paper, for one or more paper formats that can be called up , can be used for form-independent or form-correct printing as well as for the longitudinal or cross-writing method. The modular design means that the requirement can be met with a minimum of parts and volume by moving or omitting modules.

The object is achieved by the measures specified in the patent claims.

The invention is explained in more detail below using an exemplary embodiment using a drawing.

The following description is always based on a needle head for the visually readable writing and a magnetic head for the machine-readable writing, although other serial writing heads can also be used for the subject of the invention.

1 shows a needle head 1 with an ink ribbon cassette 2 and a desk 3. The paper track 4 is located between the needle head 1 and the desk 3. All paper movements take place in this and the diagonally underneath paper track 5. For this purpose, three identical rubber-covered friction rollers 6 are used, which are driven by an electric motor 10 via a common toothed belt 7 by an upstream spur gear transmission consisting of a large gear 8 and pinion 9. The two friction rollers 6 lying in the paper track 4 are so tight arranged as possible on the Nadolkepf 1 or the ribbon cassette 2. The friction roller 6 lying in the paper track 5 is arranged according to the invention in such a way that in connection with the wedge piece 11 it does not hinder the straight-line movement of a writing paper located in the paper track 4. At the desk 3, two identical counter-rollers 12 are assigned to the two opposite friction rollers and are rotatably supported in the latter. The two counter rollers are pressed against the two friction rollers 6 by a spring, not shown, acting on the desk 3.

Depending on the direction of rotation of the electric motor 10, a paper located between the roller pairs 6 and 12 can be moved back and forth between the needle head 1 and the desk 3. A magnetic head 13 embedded in the desk 3 is provided for the magnetic writing and reading of a magnetically coated paper.

The paper movement can be triggered z. B. in that a paper is inserted manually through the light barrier 14 from left to right and this starts the electric motor 10 in the direction of rotation, which rotates the friction rollers 6 in the counterclockwise direction, so that the paper detected by these is conveyed from left to right.

In the simplest case, this paper movement and expedient electronic control of the needle head 1 and / or the magnetic head 13 can be used to serialize a paper. If you only want to write or read magnetically, you can use a plastic card instead of paper. For the correct control of the needle head 1 and / or the magnetic head 13 a control cycle is required which is in a fixed ratio to the paper movement in order to ensure a high uniformity of the needle and / or the magnetic writing. If the electric motor 10 is a stepper motor, its steps are usually used as a control clock for writing. The use of a motor with a pulse disc is cheaper, but the uniformity suffers due to the tooth play of the reduction gear that is always required. For further reduction in cost and high uniformity, it is proposed in an embodiment of the invention to scan the ring gear of the large wheel 8 by means of a light barrier 15 instead of a pulse disk seated on the motor shaft (which acts directly on the friction rollers 6 via the toothed belt 7). According to the invention, the number of teeth of the large wheel 8 and the diameter of the friction roller 6 are matched to one another such that a tooth corresponds to a column of the 7 columns of a needle character or a bit of the magnetic font. By clocking heads 1 and / or 13 by means of light barrier 15, speed fluctuations in the paper drive no longer play a role. After completion of the text line, the motor 10 can be switched to reverse operation after a predetermined number of cycles, so that the paper described is output again to the left.

The sequence described above can only produce a one-line font because of the rigidly mounted write heads 1 and / or 13. However, if the print heads 1 and / or 13 are made to be displaceable perpendicular to FIG. 1, several lines can be written on the paper. Of practical interest is only the displacement of the needle head 1. Needle head 1 and ribbon cassette 2 are mounted on a carriage, not shown, which with engages a Muttargeinde in the Gawinden spindle 16 and is guided on the rod 17. The threaded spindle 16 is driven by GroPrad 18 from pinion 19 of the electric motor 20. The pinions 9 and 19 and the motors 10 and 20 are expediently the same. The ring gear of the large wheel 18 is scanned by light barrier 21 as previously described for the large wheel 8. An electronic counter (not shown) counts the pulses occurring at the light barrier 21 when the threaded spindle 16 rotates and can therefore bring the needle head 1 to a standstill at predetermined pulse numbers. (With this pulse specification, the electronic line tab is set.) Between the line jumps caused by motor 20, the paper is moved back and forth by motor 10 for the purpose of writing a line. By writing backwards "every second line, empty movements and time are saved. The line positions are defined by counting the pulses at light barrier 15 and comparing them with the specified pulse numbers (column debulator). Normally, therefore, the motors 10 and 2o always work alternately. With simultaneous specification of pulse number pairs for Row and column is also possible for plotter operation.

In a further embodiment of the invention it is provided that the needle head 1 with the ribbon cassette 2 can also be mounted perpendicular to the position shown in FIG. 1 on the carriage, not shown. According to the invention, it is further provided that the number of teeth of the large wheel 18 and the pitch of the threaded spindle 16 are matched to one another such that a tooth corresponds to one of the seven columns of a needle character. The threaded spindle 16 then moves the needle head 1 mounted with the ribbon cassette 2 for cross-printing in the direction of the cross-printing line. By the above-mentioned dimensioning is achieved so that the electronic writing program can remain completely identical in both longitudinal and transverse writing; only the feed lines of the motors 10 and 20 and the feed lines of the light barriers 15 and 21 have to be interchanged. The cross-writing method (line direction transverse to the paper transport direction) is often preferred to the longitudinal writing method because the paper movement is less (but the head movement is larger) and because journaling is only possible crosswise.

In the previously described writing processes, the paper was always fed into the writing mechanism by hand as a single form. For other applications, it is necessary to feed the paper mechanically, the paper supply as a roll or in a zigzag fold (leporello) being customary. In many cases, it is also required that several differently dimensioned and / or colored paper stocks be kept in a writing mechanism and can be controlled. Finally, it is also required that papers which have been pre-inserted or fed by machine can be written on. This task is usually carried out in separate, side by side (perpendicular to Fig. 1) paper tracks. This makes typewriters considerably wider and more expensive. Therefore, efforts are made to write by hand as machine-fed paper in the same paper path. Such a solution is already known, which, however, requires considerable effort in flaps, pawls, timing disks and tractors (DE-OS 27 15 428).

According to the invention, instead, a mechanical wallpaper feed (paper dispenser) is integrated into the previously described writing mechanism, which consists of a rocker 22 with a counter roller 23 and actuating magnet 24 consists of the parts already described at the beginning of the wedge piece 11 and the right-hand friction roller 6, which has remained unused in the previously described writing methods. The paper 25 held in roll or fan-shaped form runs from the right into the paper track 5 and is known there Way pressed by the brake pad 26 seated in the rocker 22 against the wedge piece 11. In this rocker position, the friction roller 6 projecting into the paper track 5 does not yet come into contact with the paper 25. Only after actuation of the magnet 24, the rocker 22 tilts in the counterclockwise direction such that the counter roller 23 presses the paper 25 against the friction roller 6 and at the same time the brake pad 26 lifts off the wedge piece 11 and thus releases the paper 25. If at the same time the engine 10 starts so that the friction rollers 6 rotate clockwise, then the paper 25 runs from the paper track 5 into the paper track 4 and, as already explained, can be written there in needle letters and / or magnetic letters, in one line or in multiple lines, in longitudinal letters. or be described in cross-writing. If several paper supplies are required in a writing mechanism, several paper dispensers can be arranged side by side, which cooperate with the same friction roller 6 and the same wedge piece 11. The special paper supply is selected by actuating the special actuating magnet 24.

If the paper supply is available as a form, error sum tolerances, which can result from paper stretching, slippage and friction roller wear, are inevitable despite precisely programmed row and column tabs. In this case, the paper must be provided with control holes that are always in the same position for form printing. For this there is a continuous light in the wedge piece 11 stabbed 27, which throws a narrow strip of light into the paper track 5. Opposite, in the rocker 22, there is a photo transistor 28 which is covered by the paper 25, unless a control hole runs through the paper 25. Then the phototransistor 28 emits a signal which is used for the form-correct synchronization of the column tabs in the case of the longitudinal writing or the line tabs in the case of the cross-writing.

After the writing process, the machine-fed paper 25 must be cut off automatically. For this purpose, a cutting tab must be set in the control program in the form of the number of cycles that brings the edge to be cut in the paper 25 transported out to the left to the cutting edge 29 of the rotary knife 3o and the counter knife 31. When this number of cycles is reached, the motor 10 is stopped and the rotary knife 3o is moved via the rocker arm 32, crank rod 33, crank 34 and knife motor 35. After cutting has been completed, the motor 10 is started in reverse, so that the paper 25 runs back to the right and stops when the motor 10 has reached a constant number of cycles. This number of cycles results from the length in the paper tracks 4 and 5 between the cutting edge 29 and a point about 5 millimeters to the left of the brake pad 26. This point must be such that the paper 25 is still securely gripped by the brake pad 26 on the one hand, but on the other hand no longer protrudes into the paper track 4, as a result of which the free movement of manually pre-inserted fin forms in the paper track 4 would be hindered. When the motor 10 stops, the actuating magnet 24 is also switched off, so that the welding block 26 can clamp the paper onto the wedge piece 11. After that it is Writing mechanism free again for a new writing process, be it on manually pre-inserted or on mechanically fed paper.

The advantages of the writing mechanism according to the invention are that it meets all the requirements mentioned at the beginning. and that it can be used universally by moving or omitting assemblies with a minimum of parts and construction volume.

Claims (7)

1. Electronically controlled writing mechanism in modular design, for either manually or machine-fed papers, characterized by the following components: a) a basic module consisting of a desk (3), two friction rollers (6), a toothed belt (7), a large wheel (8), a pinion (9), an electric motor (10), counter rollers (12) and light barriers ( 14.15); b) a supplementary module consisting of a writing device for machine-readable writing (13) arranged on the desk (3) and / or a pivotable electronically controlled writing device for visually readable writing (1) with an ink ribbon cassette (2) and arranged above the desk (3) with motor; c) a supplementary module consisting of a threaded spindle (16), a rod (17), a large wheel (18), a pinion (19), an electric motor (20) and one Light barrier (21); d) a supplementary module consisting of a third friction roller (6), a section (11), a rocker (22), a counter roller (23), an actuating magnet (24), a brake pad (26) and a clock-controlled cutting device (30, 31,32,33,34,35); e) a supplementary module, consisting of a light rod (27) and a photo transistor (28). 2. Writing mechanism according to claim 1, characterized in that the writing devices work simultaneously or in succession. 3. Writing mechanism according to claim 1, characterized in that the electronic control is carried out by pulses which are triggered by the light barrier (15) when the ring gear of the large wheel (8) passes. 4. Writing mechanism according to claim 1, characterized in that a pulse on the sprocket of the gear wheel (8) for paper transport as for the transverse transport of the needle head (1) is removable per column of a needle character and / or per bit of magnetic writing. 5. Writing mechanism according to claim 1, characterized in that the writing device (1) for visually readable writing is pivotable by 90 °. 6. Writing mechanism according to claim 1, characterized in that the feed lines of the motors (10, 20) and the light barriers (15, 21) are interchangeable when converting from the longitudinal writing to the cross writing method for using the same writing program. 7. Writing mechanism according to claim 1, characterized in that the number of teeth of the large wheel (8) and the number of teeth of the large wheel (18) in connection with the pitch of the threaded spindle (16) are designed so that a tooth of a column of a needle character or a Bit corresponds to the magnetic script.

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