GB2267059A

GB2267059A - Varnishing unit for a printing press.

Info

Publication number: GB2267059A
Application number: GB9309882A
Authority: GB
Inventors: Helmut Emrich; Juergen Wenzel; Toni Ehrhard; Joachim Muller; Diethelm Schroeder; Karin Huebner; Reinhold Guba
Original assignee: MAN Roland Druckmaschinen AG
Current assignee: Manroland AG
Priority date: 1992-05-15
Filing date: 1993-05-13
Publication date: 1993-11-24
Anticipated expiration: 2013-05-13
Also published as: GB9309882D0; IT1264399B1; ITMI930936A1; FR2691672B1; GB2267059B; FR2691672A1; ITMI930936A0; DE9206416U1

Abstract

A varnishing unit for a printing press is arranged as a special constructional unit after the final printing unit and upstream of the delivery. Each side wall (1) of the unit consists of a lower part (3) receiving the impression cylinder (14) and a movable upper portion (5) receiving the forme cylinder (4). Each upper portion (5) is connected pivotally by means of a rotary pivot (6) arranged fixed to the frame on the lower portion (3). Each side wall (1) furthermore has a device (8) for swinging the upper portion (5) up and down. This enables the gap between impression and forme cylinder when not varnishing (varnishing set off) in the varnishing units to be increased sufficiently to prevent pick-off of a freshly printed sheet during its running through the varnishing zone. <IMAGE>

Description

VARNISHING UNIT FOR A PRINTING PRESS This invention relates to a varnishing unit constructed as a special constructional unit which is to be arranged or installed after the last print unit and before the delivery of a sheet printing press.

A general solution is known from DE 2 345 183. By means of a changeover mechanism, according to choice, the meshing ratios of the rollers for the impression or forme cylinder respectively are adjusted differently, depending upon the drying properties of the media to be worked with. Disadvantageous is that on the application of a print without subsequent varnishing (i.e. with the varnishing process switched off), the freshly printed sheet, on running through the impression or varnishing zone between impression cylinder and forme cylinder comes into contact with the forme cylinder (despite cylinder throw-off). The freshly printed sheet "sets off" or "picks off".

From DE 3 117 855, a varnishing unit arranged in the sheet delivery is known, which has in the delivery an impression roller which can be swung away by means of an eccentric and a sheet guiding unit which can be swung in (varnishing process switched off). Disadvantageous here is that the freshly printed side of the sheet (first side printing) on running through the zone between impression roller and applicator roller nevertheless comes into contact with the applicator roller and "picks off".

A varnishing unit linearly displaceable on an inclined plane angled relative to the print unit and which can be turned down against this is known from US 4 617 865. It serves as an additional accessory for a customary print unit. This solution is laborious since, in addition to the use of rail tracks and roller elements (danger of contamination), an auxiliary frame is further necessary.

Accordingly, large masses must be moved and guided to and fro.

From WO 90/15671, likewise a varnishing unit guided on an inclined plane and linearly displaceable is known.

Furthermore, also the positioning of the front toothed gear (locking latch, index marks, etc.) from the impression cylinder and the blanket cylinder is described therein. This solution is likewise laborious, since large masses have to be moved.

In US 4 138 944, a printing press is described which has frame sections pivotable from the main frame which takes the impression cylinder. This solution serves for cleaning or for cylinder changing. It is likewise laborious, since large masses must be moved and guided (plate section).

The present invention provides a varnishing unit for a printing press, the unit being arranged as a special constructional unit to be installed after the last print unit and prior to the delivery, the unit including an impression cylinder, a forme cylinder, a metering roller and an applicator roller mounted between two side walls, wherein each side wall of the varnishing unit consists of a lower part receiving the impression cylinder and a movable upper part receiving the forme cylinder, which upper part is connected swivellably by means of a fixed rotary pivot to the lower part and which includes an adjusting device for swinging the upper part up and down to vary the distance between impression cylinder and forme cylinder as desired.

In such a unit, the lower and upper part of the side walls are, in this connection, constructed constructionally identical on each side. Likewise, the means essential for the invention, as well as the necessary functional components such as cross members, cylinder rollers, drums, are arranged movably between the side walls.

By pivoting the upper part of the side walls about the turning pivot in the lower part of the side walls and a pivotable upper part, the advantage emerges that in the printing/varnishing zone, a sufficient distance between impression cylinder and forme cylinder can be obtained so that the freshly printed sheet coming from the final print unit no longer "picks off" against the forme cylinder with the varnishing process turned off.

No large masses have to be moved and guided. Because of the fixed framework arrangement of the rotary pivots in each lower part, the lower part and upper part are positively positioned relative to one another at all times.

The invention is illustrated, by way of example, with reference to the accompanying drawings in which Figure 1 is a schematic side view of a varnishing unit according to the invention.

Figure 2 is a diagrammatic view of an adjusting device.

The varnishing unit shown in Figure 1 is arranged as a special constructional unit after the final print unit (not shown) and before the delivery (not shown).

It consists of two identically constructed side walls 1 which receive the necessary functional components. Each side wall 1 is constructed in two parts as a lower part 3 and upper part 5, wherein the lower part 3 is connected in fixed fashion with a frame 2. In the lower part 3 the functional components, an impression cylinder 14, feed drum 11 and take-off drum 12 are arranged. Drums 11, 12 are connected in each case to a chain conveyor system (not described in more detail) for sheet transport.

In the upper portion 5 are the functional components of the varnishing unit, viz. a varnishing cylinder 4, an applicator roller 9 and a metering roller 10.

On each lower part 3, there is arranged, fixed to the frame, a rotary pivot 6 in which the upper part 5 is swivellably mounted. The rotary pivot 6 is, in this connection, preferably so arranged that a roll-off free unmeshing of mutually engaged toothed gears on impression cylinder 14 and forme cylinder 4 is achieved when the upper part is rotated anti-clockwise as seen in Figure 1.

The turning point of the pivot 6 preferably accordingly lies at a right angle to the line 13 which runs through the axes of impression cylinder 14 and forme cylinder 4.

On the projection of a line 7, joining the axes of the pivot 6 and of the forme cylinder 4, there is arranged parts of an adjusting device 8, for swinging the upper portion 5 up and down preferably at right angles.

Each side wall 1, has arranged on it a constructionally identical adjusting device 8 as well as a constructionally identical turning pivot 6. The adjusting device 8 may be constructed as a screw connection, but also alternative means such as, e.g., hydraulic cylinders can be used.

In the adjusting device 8 illustrated in detail in Figure 2, parts are mounted in the upper part 5 and other parts in lower part 3. In the latter, a nut 15 is mounted rotatably laterally on the lower part 3. The lower end of a threaded bolt 16 is in threaded engagement with the nut 15. The head end of threaded bolt 16 carries a bevel gear 17, which is arranged to mesh with a further bevel gear 18 arranged on a drive shaft 19 which is rotatably mounted in a sleeve 21 constructed as a cross-member which connects both upper parts 5. Each end of shaft 19 carries for each adjusting device 8 a constructionally identical bevel gear 18.

The preferred arrangement of the direction of force of adjusting unit 8 at right angles to the projection line 7 serves to achieve a minimum force in order to swing the upper part 5 up or down with small effort.

If a print order is present which requires no print enhancement by varnishing, then from one side of the drive shaft 19, a drive 20 is introduced to rotate shaft 19. The bevel gears 18 arranged on the shaft 19 transfer the movement to the bevel gear 17 arranged on each threaded bolt 16. Both threaded bolts 16 accordingly screw synchronously out of the respective nut 15 fixed on a rotary pin 22 in the lower part 3. Via the rotary pivot 6, accordingly the upper part 5 with the functional components, forme cylinder 4, applicator roller 9, and metering roller 10 is swung round upwards so that varnishing is turned off and so that there is a sufficient distance between impression and forme cylinder 14, 4 to avoid "pick-off" of the freshly printed sheet against the forme cylinder.

If varnishing is needed for the next print order, shaft 19 is rotated in the opposite sense to screw bolt 16 down again and mesh cylinders 4 and 14 to the desired degree.

Claims

1. A varnishing unit for a printing press, the unit being arranged as a special constructional unit to be installed after the last print unit and prior to the delivery, the unit including an impression cylinder, a forme cylinder, a metering roller and an applicator roller mounted between two side walls, wherein each side wall of the varnishing unit consists of a lower part receiving the impression cylinder and a movable upper part receiving the forme cylinder, which upper part is connected swivellably by means of a fixed rotary pivot to the lower part and which includes an adjusting device for swinging the upper part up and down to vary the distance between impression cylinder and forme cylinder as desired.

2. A varnishing unit according to Claim 1 wherein the adjusting device lies substantially in the plane containing the axes of the fixed rotary pivots and the forme cylinder.

3. A varnishing unit according to Claim 1 or 2, characterised in that the rotary pivot is arranged at right angles to the transfer line running through the axes of impression cylinder and forme cylinder.

4. A varnishing unit according to any one of Claims 1 to 3 wherein the adjusting device comprises a nut arranged on the lower part of the side wall and able to swivel therein, a threaded bolt engaged in the nut and having on its head end a first bevel gear, a further bevel gear arranged on the upper part of the unit and to rest on and be supported by the first bevel gear and means to rotate the bevel gears whereby to raise or lower the forme cylinder in the upper part by swivelling the upper part about the fixed rotary pivot.

5. A varnishing unit according to Claim 4 wherein the two further bevel gears can be driven by a common shaft spanning the two side walls.

6. A varnishing unit substantially as hereinbefore described with reference to the accompanying drawings.