FLEXOGRAPHIC PRINTING MACHINE WITH SIMPLIFIED ADJUSTMENT OF THE SIDE REGISTER

Abstract

 Flexographic printing machine with simplified adjustment of the side register.
The machine comprises a rotating printing drum (1) bearing a printing material (2), and one or more printing units (3), each with a plate-bearing roller (4), an inking roller (5) and an ink supply chamber (6), arranged to change position by moving perpendicularly to the printing drum (1) between a printing position and an inactive position wherein said rollers (4, 5) and separated from each other and the first (4) distanced from the printing material (2). The rollers (4, 5) and the chamber (6) are installed on a support structure (7) mounted on holder elements (9) with portions (9a) housed in guideways (10) parallel to the shafts of the rollers (4, 5) enabling the support structure (7) to move transversely in order to make a transverse register of the plate-bearing roller (4) with respect to the printing material (2).

Description

Sector of the art

[0001] This invention concerns a flexographic printing machine with improved transversal register adjustment for the cliché-carrier cylinder in relation to the print drum.

State of the art

[0002] Documents are known that describe an apparatus or method to perform flexographic printing machine registration using an optical sensor or device. For example, patent US-6862986 describes an apparatus that includes a regulator to control axial location of stop and at least one optical scanning unit that scans the paper fabric and which is connected to the regulator. European patent EP-0504486 describes a method for performing multi-colour printing registration using a sensor to register the print drum in relation to the fabric, transversally to the transport direction. Moreover, Patent ES 2232327 describes a device and procedure for adjusting the printing with a camera that records the printing on the print material band and consecutively sends the captured images to an electronic control and regulation unit. Finally, document W04082939 describes a printing machine with an optical sensor, in which the print roller positions are adjusted by comparing the first printed marks with position signals from said optical sensor.

[0003] On the other hand, patent ES-2128892 describes a flexographic printing machine with automatic printing pre-registration in several colours, in which the central drum gearing has two type of transmission, one for production work with the printing machine and another for register pre-positioning.

[0004] Patent US-2005/0016397 A1, published as US7086330 B2, presents a printing set that includes a printing group and inking system with at least one roller, driven by rotation from various drive motors by means of their respective mechanically independent transmissions.

[0005] Document US-20060219109 is also known that describes a registration method via the axial and angular movement of then print roller and patent EP-1295721 that refers to a calibration mechanism of cylinder or print roller in the printing machine.

[0006] It is thus known how to perform transversal registration by adjusting the position of print roller or central drum and the option to move the print and inking rollers independently, each with its own motor. However, no proposals are known based on the possibility of jointly and dependently moving the print and inking rollers in the same structure for transversal registration adjustment.

Description of the invention

[0007] The invention applies to a flexographic printing machine of the type that comprises a rotating print drum on which a material to be printed is supported and, in general, several peripheral printing groups, each of which comprises a cliché-carrier and an inking roller that is associated with an ink-supply chamber, with said print group being set up to selectively change the position, moving perpendicularly to the print drum between a printing position in which said rollers, cliché-carrier and inker are in mutual contact with said material to be printed on the print drum and an inactive position in which said rollers are, in general, separated from each other and from the cliché-carrier roller for the material to be printed.

[0008] The invention proposes to simplify these transversal registration adjustment tasks (exact correspondence between the motifs to be printed) for the various colours to be printed by the cliché-carrier rollers in relation to the material that is being printed on the print drum.

[0009] The conventional solution for achieving adequate correspondence between the cliché-carrier roller motifs and the material to be printed or partially printed that covers the print drum consists of moving along the length of the cliché-carrier roller axis and, consequently, the inking roller has to be over-dimensioned and the gearing and drive motor system is complex.

[0010] The proposed solution is to install the cliché-carrier roller, inking roller and said ink-supply chamber on a common support structure, on which there are certain support elements with portions housed in guides orientated in parallel to the cited inking and cliché-carrier rollers, thus allowing joint movement of said support structure in order to perform transversal registration of the cliché-carrier roller with respect to the material being printed without any relative movement between the cliché-carrier roller and the inking roller.

Brief description of the drawings

[0011] The previous characteristics and advantages are made clearer by the following detailed description of an exemplary embodiment that refers to the attached drawing, in which:

Figure 1 is a perspective view of a flexographic printing machine that includes the improvements of this invention.

Detailed description of an exemplary embodiment

[0012] Referring to Figure 1, this shows a flexographic printing machine that comprises a print drum 1, that rotates on its own axis, which supports the material to be printed 2 and a print group 3. Figure 1 schematically shows said print material 2 as a band coming out of the machine. Said printing group 3 comprises a cliché-carrier roller 4 and inking roller 5 that is associated with ink-supply chamber 6. Moreover, this printing group 3 is arranged to selectively change position by moving perpendicularly to the print drum 1 between a printing position, in which said cliché-carrier roller 4 and inking roller 5 are in mutual contact and with said material to be printed 2 on print drum 1 and an inactive position in which said rollers 4 and 5 are separated from each other and separated the first 4 to the material to be printed 2.

[0013] In accordance with the solution proposed in this invention, the cliché-carrier roller 4, inking roller 5 and said ink-supply chamber 6 are installed on a support structure 7 that is common to said rollers 4 and 5 and said chamber 6. Said support structure 7 is installed on support elements 9 with portions 9a housed in guides 10 parallel to the axes of said rollers 4 and 5, permitting joint transverse movement of said support structure 7 in order to perform transversal registration of the cliché-carrier roller 4 with respect to the material to be printed 2. In this way, any relative movement between the cliché-carrier roller 4 and inking roller 5 is avoided.

[0014] In this exemplary embodiment, there are four support elements 9, each of which has two portions 9a that are formed by slats housed inside the U-shaped guides 10.

[0015] Said support structure 7 is transversally moved by an actuator selected from a group that includes the spindle device, linear motor, pneumatic motor and piston, among others. Although the figure does not show any of these elements, its installation layout will be evident to an expert in the material, being secured to a carrier bed. Moreover, the support structure 7 comprises two facing uprights joined by transversal strips with said lateral uprights providing supports for the ends of cited rollers 4 and 5.

[0016] An expert in the material will be able to introduce variations and modifications in the shown and described exemplary embodiment without abandoning the scope of this invention as defined in the following claims.

Claims

1. A flexographic printing machine of the type comprising a rotating print drum (1), supporting the material to be printed (2) and at least one print group (3) that comprises a cliché-carrier roller (4) and one inking roller (5) associated with an ink-supply chamber (6), with said print group (3) arranged to selectively change position by moving perpendicularly to the print drum (1) between a printing position, in which said cliché-carrier roller (4) and inking roller (5) are in contact with each other and said material to be printed (2) extended over the print drum (1) and an inactive position, in which said rollers (4) and (5) are separated from each other and separated the first (4) to the material to be printed (2), characterised in that the cliché-carrier roller (4), inking roller (5) and ink-supply chamber (6) are installed on a common support structure (7), which is installed on support elements (9), with portions (9a) housed in guides (10) orientated in parallel with the shafts of said rollers (4) and (5) thus allowing joint transverse movement of the support structure (7) to perform transversal registration of the cliché-carrier roller (4) with respect to the material to be printed (2).

2. A flexographic printing machine in accordance with claim 1 characterised in that it includes four support elements (9) and in that said portions (9a) are formed by slats housed inside said guides (10) with "U" configuration.

3. A flexographic printing machine in accordance with the previous claim characterised in that said support structure (7) is moved transversally by an actuator selected from a group that includes a spindle device, linear motor, pneumatic motor and piston among others.

4. A flexographic printing machine in accordance with the previous claim characterised in that said support structure (7) comprises two facing uprights joined by transversal strips with said lateral uprights providing supports for the ends of cited rollers (4) and (5).

Drawing