GB2189609A

GB2189609A - Testing adhesive strength of printing ink

Info

Publication number: GB2189609A
Application number: GB08708267A
Authority: GB
Inventors: Johannes Antonie De Zwaan
Original assignee: TESTPRINT BV
Current assignee: TESTPRINT BV
Priority date: 1986-04-10
Filing date: 1987-04-07
Publication date: 1987-10-28
Anticipated expiration: 2007-04-07
Also published as: CH674086A5; GB8708267D0; NL8600912A; NL193034C; NL193034B; DE3711864C2; DE3711864A1; DE8705217U1; GB2189609B

Description

GB2189609A 1 SPECIFICATION the water application roller is contacted with

the central roller, and then a lowering of the A device for testing printing inks or the like adhesive strength will be immediately detected by means of the measuring roller. As soon as A characteristic which is important for the ac- 70 the water has been expelled from the ink, the tual use of printing ink is its adhesive adhesive strength increases again. If, then, the strength. It is, therefore, important when preoriginal value will be reached again, this will paring printing ink or components thereof to mean that the ink has not absorbed water.

use measuring apparatuses by means of which It is advisable to provide the central roller the quality of an ink sample can be tested in 75 with a surface of copper or brass in which at a dependable way in respect of its adhesive least one helical groove is provided extending strength. over at least one circumferential length and There exists a measuring apparatus for this between the extremities of the central roller, 1k purpose which has satisfied very well in prac- said groove being filled with chromium and is, tice. This apparatus comprises a central roller 80 subsequently, ground the join the roller sur- to be driven by means of a motor and having face smoothly.

a surface which corresponds with the surface In this manner a simulation of a printing rol of a printing roller or plate of a printing de- ler is obtained which is suitable for measure vice, a distributing roller to be hold into con- ment, and the ink will be displaced by water tact with said central roller and being, in parti- 85 at said chromium layer, which does not take cular, movable to and fro in the axial direction, place at the brass portions. The area ratio and serving for applying an ink layer on said between the chromium and brass portions will central roller, and a measuring roller to be be chosen so that the influence of the latter contacted with said central roller and being portions is preponderant in order to obtain a supported in such a manner on swivel arms 90 measurement range which is suitable for de that, in the operative position, its axis is situ- termining the influence of the water. The heli ated substantially in a vertical plane through cal shape of said strip or strips brings about a the axis of the central roller, said swivel arms uniform distribution of the ink and the water being retained by means of springs against a over said strips, and after removing the water movement in the sense of rotation of said 95 application roller again from the central roller, central roller, means such as strain gauges be- the water on said chromium strip or strips will ing provided for measuring the drag of the be driven towards one end of the central rol measuring roller caused by the adhesive ler.

strength of the ink. Such an apparatus is, In particular the water application roller is however, only suitable for testing printing ink 100 supported on swivel arms which, in the opera (or its components) which, during printing, tive position, are driven by means of springs does not come into contact with water. with adjustable force towards the central rol In the case of so-called offset printing, how- ler, a latch being provided for allowing said ever, printing rollers or the like are used hav- swivel arms to be latched in the inoperative ing a smooth surface comprising portions re- 105 position of the application roller.

taining the ink, e.g. of brass, and other por- Preferably the swivel arms of the water ap tions retaining the ink less well, e.g. of chromplication roller are provided with a hook ium, the latter, when moistened by water, shaped extremity by means of which said repelling the ink, so that a sharply defined ink arms can be pushed on a flattened surface of transfer pattern is obtained which corresponds 110 a corresponding pivot, said arms being 1 with the pattern to be printed. If, however, adapted to be locked by means of a locking the ink absorbs water, its adhesive strength is means, said pivots each being provided with a lowered, so that when preparing inks for this lever which is engaged by a fixedly supported purpose it is to be checked how these inks compression spring.

behave in respect of water. For this purpose 115 The invention will be elucidated below in no suitable measuring apparatuses exist as more detail by reference to a drawing; show yet. ing in:

The invention provides an improvement of Figure 1 a diagrammatic lateral view of the the abovementioned known apparatus which is apparatus of the invention; suitable for the latter purpose, and which is 120 Figure 2 a partial view according to arrow 11 characterised by a water application roller of Fig. 1; adapted to be contacted with the central rol- Figure 3 a lateral view at reduced scale of a ler, and which, with its lower part, projects special central roller of this apparatus; and into a tray adapted to be filled with water, in Figure 4 a partial section at a larger scale order to allow to add, by means of this roller, 125 along the line W-W of Fig. 3 of a surface water to the ink layer applied on the central portion of said central roller.

roller. In a frame 1 of the apparatus according to By means of this apparatus the adhesive the invention a central roller 2 is supported in strength of the ink to be tested can be deter- a manner not shown, which roller is coupled mined first in the known manner, after which 130 with a suitable driving motor.

2 GB2189609A 2 An ink distributing roller 3 is supported on a manner that the roller 11 is pressed against swivel arms 4, and can be brought into con- the roller 2.

tact with the roller 2 from the position shown As appears from Figs. 3 and 4 the roller 2, by means of means not shown, and this with of which the outer portion 24 at least con a desired bias tension. The shaft of the roller 70 sists of brass or copper, is provided with heli 3 is provided with a mechanism by means of cal surface portions 25 obtained by forming which, when rotating the roller 3, the latter grooves 26 in the surface 24, said grooves can be moved to and fro in the axial direction being filled with chromium and being smoothly in order to distribute an ink layer applied on ground afterwards.

said roller uniformly over the surface of the 75 For testing printing ink at first, when the roller 2. roller 11 is kept out of engagement with the A measuring roller 5 is supported by means roller 2, a given amount of ink is applied on of swivel arms 6, and bears, in the position the roller 3, which is uniformly spread over shown, on the roller 2, the shafts of both the roller 2. By means of the measuring roller rollers being situated substantially in the same 80 3 the adhesive strength is measured in the vertical plate. The swivel axes of the arms 6 known manner. Thereafter water is applied on are connected with corresponding spring the roller 2 by means of the roller 11, which blades 8 which are clamped at 9, means such water at the strips 25 will dispel the ink. The as strain gauges being provided for measuring adhesive strength will then be reduced accord the deformation of said spring blades. Handles 85 ingly.

serve to move the arms 6 from the posi- Thereafter the roller 1 is removed again.

tion shown into the inoperative position The water is, then, driven along the helical shown by interrupted lines 6'. strips 25 towards one side, and the ink is Sofar the present apparatus corresponds to distributed again uniformly over the roller 2. If the abovementioned known apparatus. If a 90 the adhesive strength returns again to the given amount of ink has been applied on the original value, the ink has not absorbed water, roller 3, and is distributed over its surface by and, if the original value is not reached, this is rotating the roller 2, said ink layer will cause a an indication of the fact that the ink as ab certain drag of the roller 5 in its operative sorbed water indeed.

position which can be measured by means of 95 It will be clear that measurements with this the above-mentioned strain gauges. apparatus should be made at the given tem According to the invention an additional rolperature, as is also the case with the known ler 11 is provided which is supported on swi- apparatus, to which the central roller 2 can be vel arms 12, said arms being rotatable on provided with means by means of which said pivots 13 and being driven in a manner to be 100 roller can be kept at a constant temperature, described below to the right by means of in particular room temperature.

springs for contacting the roller 11 with the

Claims

central roller 2. A latch 14 contacting a fixed CLAIMS stopper pin 15

keeps, in the position shown, 1. An apparatus for measuring the adhe the roller 11 at a distance from the roller 2, 105 sive strength of printing ink or its compo and by rotating said latch by means of a nents, provided with a central roller to be handle 16 the arms 12 are allowed to move, driven by a motor and with a surface which by the spring force, towards the right suffici- corresponds with the surface of a printing rol ently for contacting the roller 11 with the rol- ler of a printing device, a distributing roller to ler 2. 110 be contacted with said central roller and be The roller 11 projects, with its lower part, ing, in particular, movable to and fro in the into a water tray 17, so that when rotating axial direction for applying a layer of the sub the roller 11 water will be transferred towards stance to be tested on said central roller, and the central roller 2, and water dripping from a measuring roller to be contacted with said the roller 2 will fall again in a tray 17'. 115 central roller, said meauring roller being sup The arms 12 have, at their upper ends, an ported in such a manner on swivel arms that, open slot 18 which, as appears from Fig. 2, in its operative position, its axis is substan fits on a flattened portion 19 of the corre- tially situated in a vertical plane through the sponding pivot 13, and said arms 12 can, axis of the central roller, which swivel arms furthermore, be fixed on the corresponding pi- 120 are retained by means of springs against a vot by means of a tensioning nut 20 or the movement in the rotational sense of the cen like. Therefore the roller 11 can be removed tral roller, means such as strain gauges being from the apparatus together with the arms 12 provided for measuring the drag of the mea after loosening the nuts 20. suring roller as a consequence of the adhesive The pivots 13 are each fixedly connected 125 strength of the layer provided on the central with a lever 21 which has a restricted swivel roller, characterised by a water application rol stroke within a cap 22 connected to the ler (11), which is adapted to be contacted frame 1, and which engages a compression with the central roller (2), and which extends, spring 23 provided in a recess of said cap with its lower portion, into a tray (17), said 22, which springs press the levers 21 in such 130tray being adapted to be filled with water, in 3 GB2189609A 3 order to add water by means of the latter roller to the layer applied on said central roller (2).
2. The apparatus of claim 1, characterised in that the central roller (2) has a surface (24) of copper or brass in which at least one helical groove (26) is provided extending over at least one circumferential length and between the extremities of the central roller (2), which groove is filled with chromium (25) and has been ground smoothly joining the roller surface.
3. The apparatus of claim 1 or 2, characterised in that the water application roller (11) is supported on swivel arms (12) which, in their operative position, are driven by means of springs with adjustable force (23) towards the central roller (2).
4. The apparatus of claim 3, characterised in that the swivel arms (12) of the water application roller (11) are provided with a hookshaped extremity by means of which said arms can be shifted on a flattened portion (19) of a corresponding pivot (13), said arms being adapted to be fixed by means of a fixing means (20) on the corresponding pivot, said pivots each being provided with a lever (21) which is engaged by a fixedly supported compression spring (23).

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon) Ltd, Dd 8991685, 1987. Published at The Patent Office, 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.

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