Tray for inking and/or collecting ink in rotogravure rotary printing machines

Abstract

 The invention deals with the field of printing machines of the rotogravure rotary type, and in particular deals with a tray (1) for inking and/or collecting ink which is coated and protected by a film (2), the film (2) being rest inside said tray (1) during the printing step.
The film (2) is kept in position, when printing, and secured to the tray by means of an ink level frame (5); the frame (5) is also placed inside the tray (1) and divides it into two areas, an ink collecting area, that is an area inside the frame (5), and another excess.ink discharging area, outside the first area and confined by the tray (1) itself. Ink is discharged from the above area by means of a discharge bush. At the end of use, the film (2) is discarded and replaced keeping the tray clean and avoiding its washing.

Description

[0001] The present invention deals with a tray for inking and/or collecting ink in printing machines, in particular for rotogravure rotary machines.

[0002] Generally many printing stations transfer fluid ink on a ribbon of paper or printable material that is continuously unwound and serially passed through all printing stations.

[0003] Ink transfer occurs by pressing the ribbon against a smooth metal cylinder engraved with small cells forming a plurality of very small recesses forming the images to be printed, that is at the same time partially immersed in a tray containing ink; when rotating, the cylinder collects ink and afterwards it is scraped by a steel blade, or doctor blade, that slides along its whole length, in such a way that it remains present only in the recesses.

[0004] As stated, printing occurs by using a plurality of cylinders, each one of which is housed in different printing units, or printing stations.

[0005] The tray inside which the cylinder is immersed has two functions:

■ keeping the printing cylinder continuously wet;

■ collecting ink scraped by the doctor blade following its withdrawal by the cylinder.

[0006] Due to what has been stated, it is clear that at the end of every printing step, there will be a tray completely dirty with ink and therefore it will have to be disassembled, replaced with an already washed one and taken to the washing chambers in order to be cleaned.

[0007] As known these are operations which must be frequently repeated.

[0008] Therefore, it is mandatory to arrange printing stations free from every previously used ink residual, both when the following colour is different from the previous one, and if the colour is the same since old ink in the meantime has dried and hardened in the tray.

[0009] Object of the present invention is solving the above inconveniences and providing an arrangement that allows reducing the tray regenerating times by interposing, between tray and printing cylinder, a thin film that keeps the internal tray surface clean preventing its contact with ink.

[0010] Another inconvenience that has to be solved is the general cleaning of the printing station, since it is well known that at the end of every cycle ink goes well outside the collecting tray due to unavoidable ink splashes generated by the printing cylinder rotation.

[0011] Another object is removing, or as a minimum reducing the above inconvenience by adequately arranging the subject film, as claimed below, in order to keep the ink area limited to the collecting tray only.

[0012] The advantages that are obtained with the tray with film of the present invention are summarised as:

■ Reduction of waiting times due to machine stops reduction for disassembling the used tray and assembling a clean tray;

■ Quick restoration of printing station operating conditions due to the quick replacement of an old film with a new one;

■ Almost complete absence of washing of the collecting tray that, preserved by the film, will conveniently be rarely washed;

■ Reduction of ink splashes outside the collecting tray.

[0013] These objects and advantages are all obtained by the inking tray for rotogravure rotary printing machines, subject of the present invention, which is characterised by what is provided in the below listed claims.

[0014] These and other characteristics will be better pointed out by the following description of some embodiments shown, merely as a non-limiting example, in the enclosed tables of drawing in which:

• figure 1 shows a perspective and exploded view of the assembly of an inking tray;
• figure 2 shows a front view of the tray;
• figure 3 shows, from a different angle, a further perspective view of the tray;
• figure 4 shows section A-A of figure 2;
• figure 5 shows a variation of use of the film in the tray.

[0015] With reference to figures 1, 2 and 3, 1 designates an inking tray, generally shapes as an open box, used for collecting and keeping a printing cylinder, designated with 9 in figure 4, wet with ink.

[0016] In the exploded embodiment in figure 1, a film 2, a gasket 3, a discharge bush 4, an ink level frame 5, a bulkhead 6 for the quick ink discharge, a cam-type lever and a collecting drum 8 are also shown.

[0017] The film 2 will be put within the internal walls of the tray 1, as protection of such surface, since ink will be collected by the film 2 itself when printing.

[0018] Such film 2 is secured to the tray by means of the ink level frame 5 inside which ink is collected before being dragged towards the discharging area, outside the frame 5 and confined by the tray 1 itself; in such discharging area, the discharge bush 4 allows ink to be discharged in the drum 8 below; this latter one will afterwards be re-circulated by a pump when working and collected at the end by a suitable operator.

[0019] The discharge bush 4 is passed in a corresponding hole obtained on the base 1 b of the tray 1; since the film 2 is abutted also on the internal wall of the base 1b, a corresponding opening 2c is obtained therein in order to allow its insertion.

[0020] The gasket 3, inserted in the bush 4, is adapted to seal from possible ink leaking between couplings of the above members.

[0021] Under the base 1 b of the tray 1 and next to the bush 4 outlet, a pair of cam-type levers 7 keep the bush 4 in place.

[0022] The wall 5a dividing the ink collecting area, inside the frame 5, and the discharging area outside, is equipped with a further removable bulkhead 6 to allow a quicker ink outflow at the end of the process.

[0023] As described and shown, the film 2 is freely placed inside the tray 1, remaining afterwards blocked due to the action of the ink level frame 5, inside the tray 1.

[0024] However, according to a further embodiment, the film 2 could conveniently be secured and made directly integral with one or more internal tray 1 walls by using known means, such as, for example, snap-type buttons, hinges, tear-type bands, Velcro® or adhesive substances.

[0025] For keeping the film in place, grease or oil can be used, that by the way make cleaning easier in case of ink leakages.

[0026] Figures 4 and 5 shows two variations of placement of the film 2 inserted inside the tray 1; in figure 4 the rear portion 2b of film 2 that goes out of the tray 1 is secured behind and/or below the doctor blade assembly, designated as 10, of the printing machine, in order to shield from splashes when printing.

[0027] In figure 5, instead, the rear portion 2b of film 2 freely goes out from the corresponding wall of the tray 1, similarly to the front portion designated with 2a.

[0028] Obviously, at the end of its use, the film 2 is discarded and replaced with a new one, and the tray 1 remains clean, thereby avoiding the washing process.

[0029] The film 2 is any polymeric material, for example polythene, but it is obvious that, without departing from the scope of the invention, any material that resists against ink and related solvents or diluents can be used for coating the tray 1.

Claims

1. Tray (1) for inking and/or collecting ink in rotogravure rotary machines, characterised in that it comprises a protecting film (2) placed in an internal surface of the tray (1), said film (2) being adapted to collect ink when printing.

2. Tray (1) according to claim 1, characterised in that the film (2) is secured to the tray by means of an ink level frame (5), said frame (5) being placed inside the tray (1) and adapted to divide the tray (1) into two areas, an ink collecting area, inside the frame (5), and an excess ink discharging area, outside the first area and confined by the tray (1) itself.

3. Tray (1) according to claim 1 and 2, characterised in that in the discharging area an ink discharging bush (4) conveys the excess ink outside the tray (1).

4. Tray (1) according to claim 3, characterised in that the discharging bush (4) is passed in a corresponding hole obtained both on the base (1 b) of the tray (1) and in the film (2) abutted in the internal wall of said base (1 b); a gasket (3), inserted in the bush (4), adapted to seal against possible ink leaking between couplings of the above members.

5. Tray (1) according to claim 1, characterised in that the rear portion of film (2) that goes out of the tray (1) is secured behind and/or below the doctor blade of the printing machine, repairing from splashes formed during printing.

6. Tray (1) according to claim 2, characterised in that the frame (5) is equipped with a removable bulkhead (6) in order to speed up ink discharge towards the opening (3).

7. Tray (1) according to claim 1 and 3, characterised in that below the base (1 b) and next to the bush (4) outlet, a pair of cam-type levers (7) keep the bush (4) in place.

8. Tray (1) according to claim 1 and 2, characterised in that the film (2) is secured to one or more internal walls of the tray (1) by using means, such as snap-type buttons, hinges, tear-type bands, Velcro®, adhesives.

9. Tray (1) according to claim 1, characterised in that the film (2) is made of a polymeric material.

10. Tray (1) according to claim 1, characterised in that the film (2) is made of a material that resists against ink and related solvents or diluents.

Drawing