DE3446226A1 - Matrix printer with a printing head arranged on a movable carrier - Google Patents

Abstract

The requirement for a high print quality which comes close to that of typewriter print is constantly increasing with matrix printers. For this purpose, mosaic printing heads with printing elements arranged in two rows of columns are known, the printing elements of one row being arranged offset with respect to those of the other row. The printing elements in the two rows of columns are actuated in delayed fashion. In order, in this process, to produce for example a straight vertical line, stepping motors are required in which exactly identical stepping widths can be achieved. The invention is based on the object of providing a mosaic printer with which a typewriter-like print quality with straight lines and high-quality coloured graphics can be produced with a machine which is of simple and cheap design. This object is achieved in that the recording carrier (1) and the printing head (2) with the printing elements are arranged so as to be capable of being moved in relation to one another by a stepping motor (8; 11), and in that a further row of printing elements can be moved into the printing position of a first row of printing elements by n-steps of the n-coil stepping motor (8; 11) in such a way that the matrix dots produced by the further row of printing elements can be placed in a position in which they are congruent with or in a position in which they are staggered between the matrix dots of the first row of printing elements on the recording carrier (1). Using simple means, it is therefore possible to ... straight vertical and/or horizontal lines with a high resolution and ... Original abstract incomplete <IMAGE>

Description

OLYMPIA WERKE AG '' "T1 / 02 / Ac / ra / PS 1992

ANR: 1 003 976 ~ December 17, 1984

Matrix printer with a print head arranged on a movable carrier

The invention relates to a matrix printer having a carrier which is movable relative to the recording medium to be printed arranged print head of the type specified in the preamble of claim 1.

The demands for a high font quality, those of the typewriter font is increasing in raster printers. For this purpose, a printhead with in two parallel, in Rows of dot printing elements arranged in the direction of the matrix columns are known from DE-OS 26 32 293. The needle tips are thereby arranged to be displaceable to one another in the vertical direction to selectively set the matrix printer either to a relatively high To bring writing speed or with a corresponding loss of writing speed to a higher print quality. The pressure elements in the parallel rows are actuated one after the other with a delay, the difference between the Print delays for one row and the next row has a constant value.

In addition, since it is written during the movement phase, especially in the case of ink printing devices, it is important that the from the Impacts caused by the drive do not cause any deterioration of the typeface as far as possible. Therefore, the printheads are attached to it Relative to the recording medium movable stepper motors to provide high manufacturing accuracy in order for all steps of the Stepper motor to achieve the same acceleration curve. The creation of vertical or horizontal lines is but not possible with cheap stepper motors with differently restless acceleration curves. On the other hand are expensive Stepper motors less suitable for cheap mass production.

The invention is based on the object of a matrix printer create, which is arranged so that it can be displaced relative to the recording medium by stepper motors that precisely straight lines can be achieved both in the vertical and in the horizontal direction. In addition, with ink printing devices multicolored inks, the raster dots of a row of printing elements can be brought exactly into overlap position with those of a further row of printing elements. This object is achieved by the invention characterized in claim 1.

The printer of the invention allows that the time of Imprint is located at the same point on the acceleration curve. This ensures that the spread the individual stepper motor coils cannot have a negative effect on the typeface. The creation of straight lines and / or more exact colored graphics is ensured in the simplest way.

Further advantageous configurations of the subject matter of the invention can be found in the further subclaims. The invention is described in more detail below on the basis of an exemplary embodiment. It shows:

FIG. 1 shows an ink printing device in diagrammatic form Depiction,

FIG. 2 shows a section through the inkjet print head, FIG. 3 shows a detail from FIG. 1 in section,

FIG. 4 shows an end face of the inkjet print head with two Rows of nozzles,

FIG. 5 shows an end face of the inkjet print head with three rows of nozzles and

FIG. 6 shows an acceleration curve assigned to the step pattern of the stepping motor.

The invention is electromagnetic in both matrix printers with individually movable needles as well as in ink printing devices. The following is an ink printing device described in more detail, FIG. 1 being a diagrammatic representation shows an ink printing device for multi-colored printing on a recording medium 1. Here, a is a plurality of printing elements containing print head 2 is arranged on a carrier 3 movable along the recording medium 1. Of the Carrier 3 is mounted on guide rails 4, 5 so that it can move longitudinally and is firmly connected to a toothed belt 6, which is connected to a belt pulley 7 is engaged. This belt pulley 7 can be driven in a known manner via a controllable stepping motor 8. The recording medium 1 is tensioned by two pairs of rollers 9, 10, one pair of rollers 10 being drivable via a stepping motor 11 is.

According to FIGS. 1 and 4, the ink print head 2 consists of two nozzle heads 12, 13 which, according to DE-C 22 33 469, are made of airtight There are interconnected plates in which the discharge and connecting channels and the pressure chambers in a known manner are incorporated. In the figure 3 z. B. shown a printing element having an ink chamber 14 which is through a elastic membrane 15 is covered. This elastic membrane 15 is designed as a piezoelectric transducer device Piezoelectric crystal 16 connected, which provides the control pulses required to generate brief pressure pulses via a control line 17 from a control circuit (not shown) receives. The piezoelectric crystal 16 is polarized in such a way that, when a voltage is applied, it follows the membrane 15 deflects inside, whereby the volume in the inner chamber 14 is reduced. This causes ink to move out of the ink chamber 14 through the connecting channel 18 from an associated outlet

nozzle 19 ejected to finally on the recording medium 1 to be applied. In the manner described above, all outlet nozzles of the two nozzle heads 12, 13 are through corresponding Pressure elements applied.

The inks emitting printing elements of the two nozzle heads 12, 13 can be actuated independently of one another, with their nozzles longitudinally two parallel and perpendicular to the relative movement between the inkjet print head 2 and recording medium 1 arranged rows are provided. Those assigned to the nozzles 19 of the nozzle head 12 Ink chambers are connected via a supply line 20 to an ink reservoir 21, the ink of black color contains. Is z. B. ejected from one of the nozzles 19 of the nozzle head 12 ink, so are recordings of graphics or text reproduced in black on the recording medium 1. The nozzles 22 and 23 of the nozzle head 13 receive ink with the Basic color yellow via a supply line 24 from a storage container 25. The outlet nozzles 22, 23 are connected to the intermediate chambers 26, 27 in fluid communication, which ink from a common Intermediate chamber 28 is supplied. This intermediate chamber 28 is firmly connected to the supply hose 24. The nozzles 29, 30 are above ink chambers 31, 32, an intermediate chamber 33 and a supply hose 34 with a storage container 35 in Flow connection that contains color with the primary color magenta. In a similar way, the nozzles 36, 37 finally stand above ink chambers 38, 39, an intermediate chamber 40 and a supply hose 41 with a storage container 42 in flow connection, which ink contains cyan. Due to the much larger number of nozzles 19 associated with the reservoir 21 with black ink are in flow connection is the creation of text and graphics with a high output speed in the coarse grid and with a low speed in the fine grid in the simplest way possible. Multi-colored graphics and symbols, on the other hand, are only possible at reduced speed, because the primary colors yellow and magenta and cyan only two nozzles 22, 23 each; 29, 30; 36, 37

assigned. The nozzles 19 of the printing elements in the first row 53 and the nozzles 22, 23; 29, 30; 36, 37 are on the same Arranged height. When printing colored images or symbols, the recording medium 1 is each by the height of two Nozzle spacings arranged displaceably, so that the individual areas of the recording medium one after the other the different Colors facing nozzles.

To create straight vertical lines, e.g. B. according to Figure 5 in the printing position of the first row of printing elements 55, the further row of printing elements 56 by η-steps of the n-coil step,
motor 8 can be brought with the rotor 58 in such a way that the raster dots generated by the further row of printing elements 56 can be brought into a gap position between the raster dots of the first row of printing elements 55 on the recording medium 1. Since the further row of printing elements 56 can only be brought into the printing position of the first row of printing elements 55 after η steps of the stepping motor 8 with the rotor 58, it is ensured that the printing process always takes place at the same point on the acceleration curve. If the stepper motor contains 8 z. B. four coils, the printing process of the second row of printing elements 56 takes place exactly after four full steps of the stepping motor 8. This enables a clean typeface and the production of straight vertical lines, with different acceleration amplitudes of the acceleration curve being switched off at the time of printing.

In ink printing devices for multi-colored printing of recording media it is necessary that ink droplets with different colors to produce mixed colors on the Recording media 1 can be brought into cover position. This is achieved according to the invention in that the different colors ejecting printing elements 22, 23; 29, 30; 36, 37 combined into groups and one behind the other in the printing element rows 54;

57 are arranged and that each group by η-steps of the n-coil stepping motor 8; 11 can be brought into the printing position of the printing elements of the adjacent group. This will ensures that the ink droplets ejected from the printing elements of one group are exactly in register with the the printing elements of the respectively adjacent group arrive in an exact covering position on the recording medium 1. Since the next printing process in each case only after η steps of the n-coil stepper motor 8; 11 takes place, is also the use of a cheap stepper motor possible, with different acceleration amplitudes of the acceleration curve at the time of Be switched off again.

In the figure 6 is an acceleration curve 60 for the stepping motors 8; 11 with z. B. \ jier coils shown. The clock tracks above represent the step grid of the motors 8; 11 and the possible grid points of the typeface. The acceleration curve 60 has different acceleration amplitudes for the different motor steps. However, the curve repeats itself after four full steps. The different acceleration amplitudes result from the scatter of the different torques generated by the four different coils and the associated stator poles. According to the invention, this scattering of the individual stepper motor coils cannot affect the typeface, since the imprint always takes place at the same point 63 on the acceleration curve according to FIG.

To create a vertical line of twenty-four points drives z. B. the carrier 3 according to Figure 1 from left to right. After the start of the third full step, a dot matrix track is created queried. The first change in brightness triggers the spraying of the twelve nozzles in the row of printing elements 56. After creating of twelve raster points on the recording medium 1, the print head 2 continues to the right. Here the point grid

- vT

Pulse rotated. After η-steps of the n-coil stepper motor 8 the row of printing elements 55 is in the printing position. The printing elements of this row of printing elements 55 are now acted upon, with raster points between the raster points of the first Print element row 56 are generated. The raster points of the first row of printing elements 56 and those of the second row of printing elements 55 form an exact straight line.

Claims (5)

OLYMPIA WERKE AG *: * "* · * · **« · * -fi / b2 / Ac / ra / PS 1992 ANR: '1 003 976 December 17, 198Γ4 Patent claims: 1. Matrix printer with a print head which is arranged on a carrier which can be moved relative to the recording medium to be printed and which has two or more heads arranged parallel to one another Has rows of printing elements, characterized in that the recording medium (1) and the Print head (2) with the printing elements (19; 22, 23; 29, 30; 36, 37) by means of a stepping motor (8; 11) relative to one another are arranged and that in the printing position of a first row of printing elements (53; 55; 56) a further row of printing elements (54; 56; 57) can be brought by η-steps of the η-coil recording stepper motor (8; 11), such that the raster dots generated by the further row of printing elements (54; 56; 57) in a cover position or in a gap position between the raster points of the first row of printing elements (53; 55; 56) can be brought onto the recording medium (1). 2. Matrix printer according to claim 1, characterized in that the printing elements of each row of printing elements (55) are arranged offset with respect to the printing elements of the other row of printing elements (56) and are so timed by a control device during the relative movement can be controlled selectively one after the other so that dots are created by the printing elements of the other printing element row (56) can be brought between the raster points of the character matrix generated by the first row of printing elements (55) on the recording medium (1). 3. Matrix printer according to claim 1 or 2 for an ink printer for multi-colored printing of a recording medium, wherein a plurality of ink containers with different colored inks are provided, each of which has supply lines are connected to a number of pressure elements that are adjacent to one another and arranged in a row, characterized in that the different colors emitting printing elements (22, 23; 29, 30; 36, 37) combined into groups and one behind the other in the rows of printing elements (54; 57) are arranged and that each group by η-steps of the n-coil stepping motor (8; 11) in the Pressure position of the neighboring group can be brought. 4. Matrix printer according to claim 1, 2 or 3, characterized indicates that the print head (2) has two or more rows of printing elements arranged vertically and parallel to one another (53, 54; 55, 56, 57) and arranged on a carrier (3) movable along the recording medium (1) and that the carrier (3) can be displaced in the line direction by the stepping motor (8). 5. Matrix printer according to 1, 2 or 3, characterized in that that the print head has two or more rows of printing elements arranged horizontally or vertically and parallel to one another and that the recording medium (1) can be transported in the column direction by a pair of rollers (10) is that can be driven by the stepping motor (11).