FR2729333A1 - UNIT OF ANCHORING - Google Patents

Abstract

The invention relates to a wetting unit. In this dampening unit for a rotary offset printing machine comprising an applicator roller (2) rolling on a plate cylinder (1), and a device (10; 10 '; 10 ") for dosing the dampening fluid, two output rollers (4; 5) are arranged parallel to one another between the applicator roll (2) and the transfer roll (6), each being in direct contact with these rollers. rotary printing.

Description

The invention relates to a wetting unit for a machine

  offset printing machine having a

  roller applicator, which rolls on the cylinder

  plate, a transfer roller preferably arranged in the form of a grinding roll, and a device for dosing the wetting agent, acting without contact or with contact. Wetting units are known comprising an applicator roll which rolls on a forme cylinder, by a transfer roll preferably arranged under the

  crusher roller (or distributor), and a

  gauging agent for the wetting fluid (see, for example,

German Patent No. 1,236,528).

  Dosing devices of the wetting agent can transmit the wetting agent on the one hand without

  contact, for example by spraying or centrifugal

  using a brush or a rotor, and secondly according to a permanent or temporary contact, for example at

  by means of a transfer roller or a moistening roller.

  A disadvantage in these wetting units arranged in a relatively simple manner is in the

  do not guarantee the formation of film

  thin and even agent of the wetting agent, as a necessary condition for quality printing. By way of aid, additives are added to the wetting agent which essentially increase the wetting - preferably in the form of an alcohol - and a series is provided.

  distributed rollers comprising a second roller

  a roller or magazine that is applied to the roller

  applicator or on a transfer roll.

  While a second applicator roller complicates the access, in particular, to forme cylinders having a small diameter and therefore complicates the replacement of the printing forms, the action of the loader rollers,

  which tend to float, on the formation of a film

  The uniformity of the wetting agent is limited.

  The object of the invention is to create a wetting unit of the type indicated above, which makes it possible, even in the case of the absence of additive increasing the wetting of the wetting agent, to produce a quality impression thanks to the formation a thin and uniform film of the wetting agent, and guarantees good accessibility in particular

  cliché cylinders with a small circumference

  as a condition facilitating the change of

clichés or forms of printing.

  This problem is solved in a wetting unit of the type indicated above, thanks to the fact that two output rollers are arranged parallel to each other between the applicator roll and the transfer roll, each being in direct contact with these rollers. Due to differently adjustable roller pressure and multiple distribution of the wetting film, the two output rollers make a decisive contribution to the smoothing of this film and therefore

  forming the film in accordance with the required quality, the

  listed below, which has an assisting action in this regard or provides favorable According to an alternative embodiment, the applicator roll, which can be removed from the forme cylinder, is mounted together with the output rollers of

  so that you can tilt around the transfer roller.

  According to an alternative embodiment, the applicator roll and the output rollers are journalled on both sides in respective levers, which are mounted so that they can tilt coaxially with the transfer roll. According to an alternative embodiment, the slot and the pressure between the output rollers and the roll

  Applicator and transfer roller are adjustable.

  According to an alternative embodiment, the device for dosing the wetting agent is disposed directly

upstream of the transfer roller.

  According to an alternative embodiment, the transfer roller is covered with chromium and the output rollers and the applicator roller are equipped with a layer

  hydrophilic rubber or plastic.

  According to an alternative embodiment, the transfer roller and the applicator roll are provided with a hydrophilic layer of rubber or plastic and the output rollers are covered with chromium or the output roll, located in the return flow, is covered with copper or the material referred to as

"Rilsan".

  According to an alternative embodiment, the rollers

  output are interchangeable.

  According to an alternative embodiment, the output roller, which is located upstream, in the direction of rotation of the transfer roller, in the main flow of the wetting fluid, and the transfer roller are alternately interchangeable. According to an alternative embodiment, the transfer roller is driven separately and the output rollers

  and the applicator roll are each driven circumferentially

by friction.

  According to an alternative embodiment, the output rollers are driven at a circumferential speed

  greater than that of the transfer roller.

  The use of a single roller applicator favo-

  make access to the cylinder and replace it

  clichés. Due to an oblique arrangement with respect to a radial direction of the forme cylinder, the central assembly of the applicator roll and the transfer roll, the conditions can be further optimized.

  space in a manner appropriate to the configuration

of the printing unit.

  Other features and benefits of the

  present invention will emerge from the description given

  Hereinafter, an exemplary embodiment of the invention, taken in reference to the accompanying drawings, the single figure shows a wetting unit arranged according to the invention and representing three different possibilities.

dosing agent of the wetting agent.

  An applicator roll 2, which is driven by friction on its circumference, of a damping unit 3 is applied against a forme cylinder 1, which is

  equipped with one or more interchangeable offset

  which must be wetted in a manner conditioned by the process during printing, the applicator roll being in contact by means of two output rolls 4, 5

  arranged in parallel and also driven by friction

  circumferentially with a separately driven transfer roll 6 arranged in the form of a roll

mill.

  The wetting fluid is transferred without contact to the transfer roller 6, by means of rotors, pins or nozzles, in variant I, while the wetting agent is transferred by a metering device 10, 10 'or 10 ", in variant II, working by establishing permanent contact by means of an inkwell roll 7 and an intermediate roll 8 and, in variant III, establishing a temporary contact by means of the roll

  ink cartridge 7 and takeup roller 9.

  To separate the applicator roll 2, the latter is appropriately mounted, together with the output rollers 4, 5, on each side, in a lever 11, mounted so as to be pivotable coaxially with the transfer roller 6 and shown by a dashed line on the drawing. The carriers of the output rollers 4, 5 may be arranged to allow separate adjustment of the roll gap and roll pressure with respect to the rolls with which they

  are in contact, for example by means of support pads.

  eccentric wearing, in combination with

  smooth, in accordance with the directional arrows

  by dashed lines.

  The transfer roller 6, which may be in the form of a driven mill roll, may be chromium-coated, and the output rollers 4, 5 and the applicator roll 2, which are respectively frictionally driven on their circumference, can be equipped with a hydrophilic layer of rubber or plastic. However, it is also possible to equip the application roller 2 and the transfer roller 6 respectively with a hydrophilic layer of rubber and plastic and to cover the output rollers 4, with chromium or to cover the roll output 4, located in the return flow, with copper or with the

material named Rilsan.

  To have better friction, the output rollers 4, 5 can be arranged to be interchangeable as desired, in which case a particular driving device can be provided, or the permutation displacement can be derived from the friction

rollers.

  It is also possible to arrange only the output roller 5, which is located upstream of the transfer roller 6 in the direction of rotation, in the main flow of the wetting agent, so that it is at

  interchangeable choice with transfer roller 6.

  Finally, it is also possible, to stretch the film of the wetting agent, to drive the rolls of

  output 4, 5 with a slip at a circumferential speed

  higher than that of the roll of

  transfer and made equal to the speed of the cylinder

picture 1.

Claims (11)

  1. Anchoring unit for a machine   rotary offset printing machine comprising an applicator roll   tor, which rolls on the platen roller, a transfer roller preferably arranged in the form of a roller   grinder, and a dosing device for the wetting agent   A contact-free or contact-operated step characterized in that two output rollers (4; 5) are arranged parallel to each other between the applicator roll (2) and the transfer roll (6), being each in direct contact with these rollers.   Fountain unit according to claim 1, characterized in that the applicator roll (2), which can   removed from the platen roller (1), is mounted   jointing with the output rollers (4; 5) so as to   to be able to tilt around the transfer roller (6).   Fountain unit according to claim 2, characterized in that the applicator roller (2) and the output rollers (4; 5) are journalled on both sides in respective levers (11), which are mounted so as to be able to switch, coaxially to the roll of transfer (6).   4. Wetting unit according to claims 1   with 3 sockets as a whole, characterized in that the slot and the pressure between the output rollers (4; 5) and the applicator roll (2) and the transfer roll (6) are adjustable.   Wetting unit according to claims 1   characterized in that the device (10; 10 '; 10 ") for dosing the wetting agent is arranged directly upstream of the transfer roller (6).   Wetting unit according to claims 1   characterized in that the transfer roller (6) is covered with chromium and the output rollers (4; 5) and the applicator roller (2) are provided with a hydrophilic layer of rubber or plastic material.   Wetting unit according to claims 1   characterized in that the transfer roller (6) and the applicator roller (2) are provided with a hydrophilic layer of rubber or plastic and that the output rollers (4; 5) are covered with chromium or that the outlet roll (4), located in the return flow, is covered with copper or   material referred to as "Rilsan".   Damping unit according to claims 1   taken as a whole, characterized in that the   output rollers (4; 5) are interchangeable as desired.   Wetting unit according to claims 1   7 in taken together, characterized in that the output roller (5), which is located upstream in the direction of rotation of the transfer roller (6), in the flow   wetting fluid, and the transmission roller   fer (6) are interchangeable.   Mooring unit according to claims 1   at 9, characterized in that the transfer roller (6) is driven separately and the output rollers (4; 5) and the applicator roller (2) are driven each   circumferentially by friction.   Wetting unit according to claims 1   9 taken together, characterized in that the output rollers (4; 5) are driven at a circumferential speed greater than that of the roll of transfer (6).