EP0064668A2 - Pivot for a printing mechanism - Google Patents

Abstract

A printing unit is guided along a straight line in parallel relation with the printing plane of a printing support. A device is arranged to pivot the printing unit between at least two printing supports spaced angularly apart. The device includes a coupling assembly interconnecting the printing unit with a drive member. A part of the coupling assembly includes a slotted crosshead or plate in which rollers move through branch slots disposed angularly to one another. Due to the guidance afforded the printing unit as it is pivoted between different angularly spaced printing supports, it moves along a curve significantly flatter than the arc of a circle on which the printing planes of the printing supports are located.

Description

The invention relates to a swiveling device for a printing unit which is displaceable parallel (in the direction of the line) to a printing base but can be pivoted in the printing position to a plurality of different printing bases and which comprises a printhead and a carriage which is spaced as far apart as possible for its movement in the line direction Printing web width arranged side parts on guide parts is movable.

In the swiveling device for a printing unit described in DE-OS 28 23 153, the print head with its pressure point - the pressure point is defined as the point of contact of the middle printing needle in a mosaic printer - moves in a circular path from one printing position to the other relative to two different ones Printing materials. This type of movement of the print head from one printing position to the other printing position has the consequence that the overall arrangement has a relatively large overall height, which is of little advantage for use in a printing device, for example to be arranged on a table, since then the printer would become so high that it is no longer possible for the operator to see the upper printing point.

In addition, the printhead moves during its pivoting movement on a very flat path into the printing position, so that due to various paper guide parts which are arranged near the printing position on the printing pad, the pivoting of the printhead can only take place in certain positions, so that it is not caused by the aforementioned Paper guide parts is hindered.

Another disadvantage of the known arrangement is that in the crank mechanism used here for pivoting the printing unit, the pivoting device is locked is only possible in the two end positions defined by the dead center positions of the crank mechanism; partial positioning is not possible in this case.

In contrast, the invention has for its object to provide a pivoting device for a printing unit with a relatively low profile, which allows printing of several printing documents, so that a table workstation printer can be created, in which the operator can still follow the printing process on the upper printing pad.

According to a further object of the invention, it should be possible to operate the swiveling device in such a way that a partial swiveling is also possible by stopping the swiveling device after a certain smaller or larger angle. Furthermore, the pivoting of the print head should be able to take place in the same in any lateral position.

The swiveling device according to the invention is characterized in that the pivoting of the side parts with the printing unit serves a transmission which consists of a fixed, partial cross-loop and a coupling guided therein with two end points, on which the drive element acts and with which the side parts of the printing unit are connected , wherein the planes intersecting the pressure points in their end positions, which run perpendicular to the print planes on the printing documents, essentially intersect the coupling between their end points.

In another embodiment of the transmission, this consists of a gear connected to the side parts, which rolls on a fixed internal toothing of a guide part during its drive movement, the diameter of the gear and the internal toothing behaving like 1: 2, so that the gearwheel is between forms the two engagement points with the internal toothing in one and the other printing position extending coupling.

The swiveling device according to the invention has the advantage that the printing unit moves in its swiveling on a very steep path into the printing position, which has the advantage of a significantly smaller space requirement than the circular path. In the case of two printing documents and two printing positions, the cross loop with two branches is arranged so that one branch is vertical and the other horizontal, the printing planes running parallel to the connecting line between the end points of the coupling. This arrangement has the advantage that a section is selected from the path of movement of the pivoting device, which causes the printhead to move almost vertically into the printing position, in particular at the end of the pivoting movement. Any component penetrations with paper guides etc. are therefore avoided, the pivoting movement can be effected in any lateral position of the print head.

If a stepping motor is used as the drive element for the swivel device, digitized partial positioning is also possible, with the result that the printhead does not have to be swiveled to its other end position each time, but rather can only swivel it so far, for example, that the view is released on the print image. Also, with such a partial positioning of the printhead, a special retraction of the printhead for the purpose of connecting the recording medium in rows is no longer necessary, which results in a simplification of the printing unit (printhead and carriage).

Another advantage of partial positioning is that the printhead can only be pivoted, for example, by the width of a single printing needle. In this case, it is possible to print over the same line several times to produce a print that corresponds to the correspondence, because then the second print fills the gaps (rounding of the print needles) of the first print. Further features and advantages of the subject matter of the application result from the following description of an embodiment of the invention.

• FIG. 1 eine Draufsicht auf die Gesamtanordnung,
• FIG. 2 ist eine Ansicht der Schwenkvorrichtung in der einen Position, während
• FIG. 3 die gleiche Vorrichtung in der anderen Schwenkposition zeigt.
• FIG. 4 ist eine schematisierte Darstellung,
• FIG. 5 eine vereinfachte Darstellung einer zweiten Ausführungsform.

In the accompanying drawings

• FIG. 1 shows a plan view of the overall arrangement,
• FIG. Figure 2 is a view of the pivoting device in one position while
• FIG. 3 shows the same device in the other pivot position.
• FIG. 4 is a schematic representation,
• FIG. 5 shows a simplified illustration of a second embodiment.

In FIG. 1 can be seen in front of a printing pad 1, a printing unit 2, which consists of a carriage 3 and the actual print head 4, the mouthpiece 5 of which is located directly in front of the printing pad 1 via an ink ribbon 6 and inscribes a paper on the printing pad 1 with its printing needles, not shown. The level in which the printing needles act on the base 1 is the first printing level D ₁ (FIG. 4). The ink ribbon 6 is removed from a cassette 7, which consists of two parts 7a and 7b, which is arranged on a guide 8 to the right and left of the printing position 9. The ink ribbon 6 is stored in part 7a of the cassette, is conveyed by drive means in part 7b and is guided in front of the printing position 9.

The printing unit 2 is mounted and guided on an axis 10 as a guide part, which is between two side parts 11 and 12 is held. A motor 13 is arranged on the right side part 11 and drives the printing unit 2 on the guide axis 10 via a belt wheel 14, a belt 15 and a further belt wheel (not shown), so that it is displaced in the line direction to the pressure on the printing substrate 1 to effect.

The second printing pad 16 (see FIG. 3) is arranged at an angle of approximately 90 ^° to the first printing pad 1, in which case the print head prints the pad from top to bottom. The plane in which the print head 4 interacts with the second printing pad defines a second printing plane D _{2 '.} To this end, one can define two planes P ₁ and P ₂ in which the printing points A ₁ , A ₂ lie, ie the point in which the middlemost printing needle has the printing planes D ₁ . D ₂ touches.

The side parts 11, 12, the axis 10 as a guide part and the printing unit 2 are pivoted by the pivoting device to be described in the following so that the print head 4 prints either on the printing pad 1 or on the printing pad 16.

With specific reference to FIG. 2 and 3, the pivoting device for the printing unit 2 will now be described. With the guide part, the axis 10, and thus also with the side parts 11 and 12, the coupling 17, which on the left side consists of the two parts 18 and 19, which are connected to one another. On the right side, the coupling 17 consists only of the part 19 with the rollers 20 and 21 attached to it, as can also be seen from FIGS. 2 and 3 results. The two rollers 2o and 21 are rotatably attached to two corners of the square part 19 and are guided in two branches 22 and 23 of a partial cross loop 24. The rollers 2 ₀ , 21 form the end points of the coupling 17. The two branches 22 and 23 are Grooves in one pass tion plate 25 which is fixedly attached to a side support plate 26. The end positions of the two rollers 2o and 21 are limited by stop levers 27 and 28, which are under the action of springs 29 and 30. If the roller 21 in the position shown in FIG. 2 end position shown, the spring 30 is somewhat tensioned. As a result, the spring 30 supports this movement in the sense of an additional acceleration at the beginning of the movement of the coupling 17, so that the movement process can start up quickly. On the other hand, the spring 30 dampens the pivotal movement at the end thereof. The situation is similar with the stop lever 27. When the coupling 17 is in its other end position, see FIG. 3, then the roller 20 presses the stop lever 27 outwards, so that the spring 29 is slightly tensioned. Here, too, the spring 29 acts to accelerate the start-up of the pivoting device when another position is to be assumed and to dampen it. At the same time, the stop levers 27, 28 still relieve the weight.

In order to pivot the coupling 17 and thus the printing unit 2 with its guide and side parts 1 ₀ , 11, 12, a bow-shaped part 31 is fastened to the coupling 17, 18, 19, in which a nut 32 is rotatably mounted. Passed through the nut 32 is the drive spindle 33, which is driven by a gear 34 from the axis 35 of a stepper motor 36.

On an additional holding part 37 two microswitches 38 and 39 are still attached, which cooperate with two switching levers 40 and 41. The shift levers 40 and 41 are controlled by staggered bolts 42 on the parts 18 and 19 so that the one microswitch in one end position of the coupling 17 and the other microswitch in the other end position of the coupling 17 is closed to the end positions of the transmission to report to the electronics.

The parts according to FIG. 2 and 3, insofar as they relate to the actual drive, that is to say the stepping motor 36, the spindle 33 and the nut 32 with the bracket part 31, are only arranged on the left side of the printing device. On the right side there is also part 19 of the coupling 17 with the two rollers 2o and 21 and part 25 with the cross loop 24. The stop levers 27 and 28 are of course also present twice.

When pivoted, the stepper motor 36 is switched on. It drives the spindle 33 via the gearwheel 34, the nut 32 moves on the spindle 33 and thereby also the coupling 17 in FIG. 3 pivoted counterclockwise. The rollers 21 and 20 move in the cross loop 24 from the position shown in FIG. 3 in the position shown in FIG. 2. In this sale, the printing unit 2 interacts with the printing pad 16. If, on the other hand, the motor is driven in the other direction, the coupling 17 with the two rollers 20 and 21 moves in the cross loop 24 from the position shown in FIG. 2 back to the position shown in FIG. 3. In this position, the printing unit 2 acts on the printing pad 1.

As already explained, it is of course also possible, depending on the program, to run the motor 36 only by so many steps that the needle head 5 just releases the printing position 9 so that the typeface can be recognized. On the other hand, it is of course also possible to adjust the motor only by the width of, for example, a needle tip, so that when you pass over the printing pad twice, 1 character is created in which the points that normally occur during needle printing are doubled so that all gaps between the individual Points are covered.

To illustrate the basic structural design, FIG. 4 is a schematic representation in which the two pressure planes D ₁ , D ₂ , the two positions of the coupling 27 in the cross loop 24 and the planes P ₁ . P ₂ , the in pressure points A ₁ . A ₂ stand vertically on the printing planes. In the case shown here, the planes P ₁ , P ₂ intersect the coupling perpendicularly, which is not necessary, however, if, for example, the two branches of the cross loop have a different angular position to the printing planes. One can see in FIG. 4 also the path B ₁ , on which the print head moves between the printing substrates 1 and 16 or printing planes D ₁ and D ₂ . Compared to a circular path, the printhead is pulled back relatively quickly at the beginning of the pivoting movement and at the end of the same, it plunges again just as steeply into the other printing position.

FIG. 5 shows in a schematic representation that the two-part transmission consisting of coupling and cross-loop can also be designed differently. In this case, a gearwheel 40 is the coupling which interacts with a fixed guide part 42 with an internal toothing 41. The diameter of the internal teeth 41 is twice as large as the diameter of the gear wheel 4 _0th The spindle 33 and the motor 36 then act on the gearwheel 40 by means of a suitable connecting member in order to generate the rotary movement. If the gear 4o rotates clockwise, then it rolls on the internal toothing 41 until it has reached the position shown in broken lines after half a revolution. The respective position of the printing planes D ₁ , D ₂ and the print head can also be seen. In this case, the end points of the coupling are the engagement points of the gearwheel 4o with the internal toothing 41 in the two end positions, which are represented by a connecting line K ₁ . It can be seen that the printhead also travels a very steep path B ₂ when pivoting between the pressure points A ₁ and A ₂ .

Claims (7)

1. Swivel device for a parallel (row-direction) to a _D ruck pad (1, 16) displaceable, but in the printing position (9) to a plurality of different printing documents (1, 16) pivotable printing unit (2) which consists of a print head (4) and there is a carriage (3) which is movable on guide parts (1 ₀ ) for its movement in the line direction between side parts (11, 12) arranged on both sides at a distance of the greatest possible printing web width,
characterized,
that the pivoting of the side and guide parts (1 ₀ , 11, 12) with the printing unit (2) serves a gear, which consists of a fixed partial cross loop (24) and a coupling (17) with two end points (rollers 2 ₀ , 21), -on which the drive element (36, acts 33) and with the side parts (11, 12) of the printing unit are connected, wherein the pressure points (A _1, A ₂₎ intersecting in their end positions planes (P ₁ , P ₂ ), which run perpendicular to the printing planes (D ₁ , D ₂ ) on the printing documents (1, 16), cut the coupling (17) essentially between or in their end points (2o, 21). 2. Swiveling device for a printing unit (2) which can be moved parallel (in the direction of the line) to a printing base (1, 16) but can be pivoted in the printing position (9) to several different printing bases (1, 16) and which consists of a print head (4) and a There is a carriage (3) which is arranged to move in the line direction between the two sides at a distance from the largest possible printing web width th side parts (11, 12) on guide parts (10) is movable,
characterized,
that the pivoting of the side and guide parts (1 ₀ , 11, 12) with the printing unit (2) serves a gear, which consists of a connected to the side parts, driven by a drive element gear (4o), which in its drive movement on a fixed internal toothing (41) of a guide part (42) rolls, the diameter of the gear and the internal toothing behave as 1: 2, so that the gear (4o) one between the two engagement points with the internal toothing in one and the other printing position extending coupling forms, the planes (P ₁ , P ₂ ) intersecting the printing points (A ₁ , A ₂ ) in their end positions, which run perpendicular to the printing planes (D ₁ , D ₂ ) on the printing documents (1, 16), cut the coupling (17) essentially between or in their end points (2o, 21). 3. Swivel device according to claim 1,
characterized,
that with two printing documents (1, 16) arranged at an angle of approximately 90 °, one branch (22) of the cross loop (24) is vertical, the other (23) is horizontal and that the printing planes (D ₁ , D ₂ ) are parallel to the connecting line between the end points (20, 21) of the coupling (17). 4. Swivel device according to claim 1 and 2,
characterized,
that a motor (36) with a spindle (33) serves as the drive element, which acts on the coupling (17) connected to the nut (32). 5. Swivel device according to claim 1, 3 and 4,
characterized,
that the coupling (17) is provided at its end points with rollers (2o, 21) which are guided in the two branches (22, 23) of the cross loop (24). 6. Swivel device according to claim 5,
characterized,
that the end position of the rollers (2o, 21) in the branches (22, 23) of the cross loop (24) is limited by spring-loaded stop levers (27, 28), so that the springs (29, 3 ₀ ) are tensioned when the end position is reached . 7. Swivel device according to claim 1 to 3,
characterized,
that the motor (36) is a stepper motor that allows digitized partial positioning of the swivel device.

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