EP1333984A1

EP1333984A1 - Printing device

Info

Publication number: EP1333984A1
Application number: EP01994543A
Authority: EP
Inventors: Rainer Eck; Michael Koblinger; Karl Erich Albert Schaschek
Original assignee: Koenig and Bauer AG
Current assignee: Koenig and Bauer AG
Priority date: 2000-11-17
Filing date: 2001-10-15
Publication date: 2003-08-13
Anticipated expiration: 2021-10-15
Also published as: DE10057061C1; US6742867B2; US20040037603A1; EP1333984B1; AU2002223485A1; ATE416925T1; WO2002040279A1; DE50114571D1

Abstract

A printing device includes a plurality of print heads, each of which has a printing zone. An extension of this printing zone in a direction of printing defines a line height and an extension of this printing zone perpendicular to the direction of printing defines a column width. The printing heads are arranged in several parallel rows which are located at a distance from one another. The print heads in different rows are offset in relation to each other in a direction perpendicular to the direction of printing. A separation distance between the print heads in each row corresponds to the column width multiplied by the number of rows. The distance between the rows corresponds to the line height multiplied by the number of rows plus one.

Description

description

printing device

The invention relates to a printing device according to the preamble of claim 1.

The printing device is provided with a multiplicity of printheads, each having a printing area, the extent of which in the printing direction defines a row height and the extent of which transversely to the printing direction defines a column width, the printheads being arranged in a plurality of mutually spaced parallel rows and the printheads of different rows being transverse to the printing direction are offset from one another.

The term “printing direction” means the direction of the movement of the printing material to be printed relative to the printing heads. If printing plates mounted on rotating printing plate cylinders are provided as printing material, the printing direction is perpendicular to the axis of rotation of the printing plate cylinder.

Such printing devices are used, for example, to image offset printing plates. A coating agent or, conversely, a solvent for dissolving a coating on the printing plate can be sprayed onto the plurality of printing heads.

In order to obtain a high-quality print image, it is desirable to be able to apply the medium to be applied to the printing plates by means of the printing device in a finely and evenly distributed manner in every area of the printing plate without any defects. For this purpose, the print heads must be arranged close enough to each other. On the other hand, the possible density of the printheads being packed together is limited because they abut. In this respect, it would be desirable to use as few print heads as possible. US 57 19602 A shows an ink jet print head with a large number of nozzle groups. These groups of nozzles are staggered.

DE 3730 844 A1 discloses a matrix ink printer in which a plurality of print heads, each having a plurality of nozzle openings, are arranged offset from one another. The nozzle openings cover each other based on the material to be printed.

The invention has for its object to provide a printing device.

This object is achieved by the features of claim 1.

The advantages that can be achieved with the invention are, in particular, that the pitch of the print heads in each row of print heads corresponds to the column width times the number of rows and the distance between the rows corresponds to the row height times the number of rows increased by one. The column jumps in a print head row correspond to the number of print head rows, while the line jumps between adjacent print head rows are greater by one than the number of print head rows of the printing device. The printheads are arranged exactly in such a way that there are no gaps and no overlaps between the printheads where no or double printing would take place. This enables a high resolution to be achieved with a compact design of the printing device.

Print heads from different rows are advantageously arranged in a common plane. In particular, a printhead from each row can lie in a common plane with a respective printhead from every other row. This considerably simplifies the assembly of the individual printheads. In particular, these can be attached to a flat print head holder. In addition to a compact arrangement, the printheads can be easily aligned relative to one another. In a further development of the invention, the individual print heads are arranged at an angle to the printing direction in order to achieve a higher resolution. Each print head has a longitudinal direction, which is determined by its print area or by the line along which the nozzle openings are arranged. The print heads are arranged at an angle to the printing direction in such a way that the longitudinal direction mentioned extends at an acute angle to the printing direction. The angle can be adapted to the circumstances, in particular to the design of the print heads. According to one embodiment of the invention, the angle can be between 20 ° and 45 °, in particular approximately 30 °.

In a further development of the invention, the print heads from different rows are inclined by the same angle. In particular, they can be arranged such that printheads from different rows lie in a common plane with their longitudinal directions. The common plane is inclined to the printing direction by the angle by which the print heads are also inclined to the printing direction.

Embodiments of the invention are shown in the drawings and are described in more detail below.

Show it:

Fig. 1 is a schematic representation of the arrangement of the print heads

Printing device in two rows according to a preferred embodiment of the invention;

Fig. 2 is a schematic representation of the arrangement of the print heads

Printing device in three rows according to a further preferred embodiment of the invention. 1 comprises 18 individual printheads 1 to 18, which are arranged in two rows of printheads. The rows of print heads extend at a distance from one another and parallel to one another, in each case perpendicular to the printing direction 19, which is indicated by the arrow.

All print heads 1 to 18 are each inclined by an angle of inclination 20 to the printing direction 19 in order to achieve a higher resolution. Due to the inclined position of the printheads 1 to 18, the printheads 1 to 18 can be arranged closer to one another in the direction of the printhead rows and the distance between the nozzle openings of the individual printheads 1 to 18 from one another transversely to the printing direction 19 can be reduced. As shown in FIG. 1, the angle of inclination 20 is defined on the one hand by the printing direction 19 and on the other hand by the longitudinal direction of each print head 1 to 18. The longitudinal direction of the print heads 1 to 18 is determined by the line along which the nozzle openings of a print head 1 to 18 are arranged. Due to the inclination, the row of nozzles of each printhead 1 to 18 has an extension in the printing direction 19 and an extension transverse to the printing direction 19. The extension transverse to the printing direction 19 determines the column width of a printing head 1 to 18, while the extension of the nozzle row in the printing direction 19 determines the line height of the corresponding print head 1 to 18.

The printheads 1 to 18 in each printhead row are spaced apart from one another transversely to the printing direction 19. The pitch 21 of the print heads 1 to 18 of a print head row corresponds to the column width times the number of print head rows, in the embodiment shown in FIG. 1, the width of two columns:

Pitch 21 = column width x number of print head rows

The rows of print heads are also spaced apart from one another in the printing direction 19. The Row spacing 22 satisfies the following condition:

Row spacing 22 = row height x (number of print head rows + 1)

In the case of two rows of print heads, as in the embodiment shown in FIG. 1, the row spacing 22 corresponds to three times the row height, which, as mentioned, is defined by the extension of the row of nozzles of a print head 1 to 18 in the printing direction 19.

According to the selected arrangement of the print heads 1 to 18, the next print head 1 lies transversely to the print direction 19; 2; 3; 4; 5; 6; 7; 8th; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18 always in the next row and is not in the same row of print heads. As the numbering of printheads 1 through 18 shows, is a first printhead

1 arranged in the first printhead row, while the subsequent second printhead

2 is arranged in the second row of print heads.

In this printhead arrangement it can advantageously be provided that a plurality of printheads 1 to 18 are arranged in a common plane, so that they can be mounted on a planar holder. As shown in Fig. 1, the print heads 1 and 4, the print heads 3 and 6, etc. are in a common plane and are each mounted on a common print head holder 23 and 24, respectively.

This common plane of the nozzle openings of the printheads 1 and 4, 3 and 6 etc. is inclined to the printing direction 19 at the angle of inclination 20 and is perpendicular to the printing plane, i. H. to the substrate. In the case of a rotating substrate, e.g. B. a printing form of a rotating cylinder of a printing press, the plane is inclined to the axis of rotation of the cylinder and lies in the radial direction of the cylinder.

It is fundamentally possible to use the printhead holder 23; 24 mounted printheads 1 to 18 on different sides of the same to fix or arrange. A However, a simpler and preferred arrangement is that the printheads 1 and 4 mounted on a printhead holder 23 are arranged on the same side of the printhead holder 23, as shown in FIG. 1.

The print head holder 23; 24 can be mounted on a common carrier 25 (FIG. 1).

The number of print head rows is preferably selected depending on the space requirement. 2, the print heads 1 to 18 can be arranged in three rows of print heads. Otherwise, the arrangement of the print heads 1 to 18 according to FIG. 2 corresponds to the arrangement according to FIG. 1. In particular, the column jumps between the print heads 1 to 18 correspond to a row of print heads and the line jumps, i. H. the row distance in the printing direction 19 of the above relationship. Likewise, the inclination of the individual print heads 1 to 18 corresponds to the relationship described above. A further explanation of the embodiment according to FIG. 2 can therefore be dispensed with.

This printing device applies a means for changing the coating (an additional coating can be applied, properties of a coating can be changed) of a printing form, in particular a planographic printing form of a printing press.

LIST OF REFERENCE NUMBERS

1 printhead

2 printhead

3 printhead

4 printhead

5 printhead

6 printhead

7 printhead

8 printhead

9 printhead

10 printhead

11 printhead

12 printhead

13 printhead

14 printhead

15 printhead

16 printhead

17 printhead

18 printhead

19 printing direction

20 inclination angles (1 to 18)

21 pitch (1 to 18)

22 row spacing

23 printhead holder

24 printhead holder

25 carriers

Claims

Expectations

1. Printing device with a plurality of print heads (1 to 18), each having a printing area, the extent of which in the printing direction (19) defines a line height and the extent of which transversely to the printing direction (19) defines a column width, the printing heads (1 to 18) arranged in a plurality of mutually spaced parallel rows and the printheads (1 to 18) of different rows are offset from one another transversely to the printing direction (19), characterized in that the pitch (21) of the printheads (1 to 18) is in each case one row the column width times the number of rows and the row spacing of the rows corresponds to the row height times the number of rows increased by one.

2. Printing device according to the preceding claim, characterized in that print heads (1 to 18) from different rows are arranged in a common plane, in particular in each case a print head (1; 3; 5; 7; 9; 11; 13; 15; 17 ) from each row with a respective printhead (2; 4; 6; 8; 10; 12; 14; 16; 18) from every other row lies in a common plane.

3. Printing device according to one of the preceding claims, characterized in that each print head (1 to 18) by its printing area, ie. H. has the longitudinal direction determined by the position of the nozzle openings and is arranged at an angle to the printing direction (19).

4. Printing device according to one of the preceding claims, characterized in that the print heads (1 to 18) are arranged such that print heads (1 to 18) from different rows lie with their longitudinal direction in a common plane.

5. Printing device according to one of the preceding claims, characterized characterized in that printhead holders (23; 24) are provided, on which printheads (1 to 18) from different rows are mounted, in particular at least one printhead (1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18) is supported from each row, the printhead holders (23; 24) preferably being flat, in particular having at least one flat surface.

6. Printing device according to claim 1, characterized in that the printing device applies a means for changing the coating or a coating of a printing form.

7. Printing device according to claim 6, characterized in that the printing form is designed as a planographic printing plate.