Title of Invention

APPARATUS FOR APPLICATION OF DYE TO A WEB

Abstract The invention relates to an apparatus for the application of dye to a web with a screen and a roll doctor for pressing the dye through the screen onto the web, the roll doctor (2) being guided rotatable -preferably over its whole length -in a tunnel (5) of a guide body (3), the roll doctor projecting with a part of its circumferential surface over the tunnel (5) on a longitudinal slit facing the screen (6), and the tunnel wall (5a) being constructed such that it rests against the outside of the roll doctor (2) only at several guide points (10) spaced apart in longitudinal direction of the tunnel, whilst between these guide points (10) it runs at a distance (d) from the roll doctor (2), the tunnel wall (5a) having preferably concavely arched indentations (11) between the guide points (10), wherein that the tunnel (5) is constructed such that the dye paste adhering to the roll doctor (2) is returned into the application front, i.e. into the dye sump located in front of the roll doctor (FIG 5)
Full Text

Apparatus for application of dye to a web
The invention relates to an apparatus for the application of dye to a web with a screen and a roll doctor for pressing the dye through the screen onto the web, the roll doctor being guided rotatable - preferably over its whole length - in a tunnel of a guide body, the roll doctor projecting with a part of its circumferential surface over the tunnel on a longitudinal slit facing the screen.
Several holding devices for roll doctors have already become known, for example, the roll doctor can be placed essentially loosely in the rotary screen, being guided simply by running up against a supporting bar parallel to the roll doctor, whilst being pressed against the inside of the screen by a magnet arranged under the backing cloth.
Furthermore, roll doctors according to the preamble housed in tunnel-shaped longitudinal bores are known e.g. from EP 0095084 A1, GB 2040738 A, GB 2078140 A or DE 19602483 C1. These however have the disadvantage that an accumulation of dye occurs in the tunnel-shaped longitudinal bore along the whole of or in sections of the length of the roll doctor as a result of its rotation. With very viscous dyes or dye pastes, this can lead to the slowing-down and in extreme cases even to the blocking of the roll doctor.
The object of the invention is to create an apparatus of the type named at the outset with an improved housing for the roll doctor so that the latter remains well rotatable even when using highly viscous dyes, accumulations of dye are avoided, and a precise mechanical guiding of the roll doctor is nonetheless possible.
This is achieved according to the invention in that the tunnel wall is constructed such that it rests against the outside of the roll doctor only at several guide points spaced apart in longitudinal direction of the tunnel, whilst between these guide points it runs at a distance from the roll doctor.
Preferably a tunnel-like guide is provided, enclosing the roll for more than half its diameter, which gives the roll permanent protection against bending and an easily damaged surface. In addition, the tunnel wall is designed in a shape which guarantees for the application function, in particular the Theological behaviour of the dye pastes in the case of all dye families and their applied viscosities, a uniform

application and, after the application carried out in/on the screen, a drip-free screen field after the application.
The roll guide in the tunnel is a series of ribs matched to the roll diameter, wherein the ribs can be spaced a roll diameter apart over the length of the tunnel. The roll is housed in the ribbed tunnel with minimum play, i.e. smoothly running.
Indentations which, in the case of a dye-applying roll, enable dye to flow are located between the ribs. When imprinting dye pastes with roll doctors, a dye film remains on the cylinder wall of the roll. This dye film, which can be particularly thick in the case of highly viscous dye pastes, is pumped back into the application front through the rotating roll and the indentations located between the guide ribs. As a result, a formation of drips, which would occur with a flat tunnel wall, is prevented. Pastes which lie in the highly viscous range tend to bring the roll to a stop at high printing speeds as a result of their causing the paste to slow down. As a result of the indentations arranged in the tunnel wall between the guide points according to the invention, an accumulation of the dye or paste in the tunnel and the associated slowing-down effect are avoided. Overall, a throughflow doctor or tunnel doctor results.
The tunnel body is preferably composed of a slipping plastic, whereas the application roll is composed of a magnetically active material which can be provided with a material which hardens the surface, e.g. hard chromium.
The guide body with the tunnel and the roll doctor cannot be separated in normal use. Nonetheless, the unit comprising guide body and roll doctor can more favourably be developed removable, for replacement purposes. Although the roll doctor fits closely in the tunnel, the tunnel and the roll doctor can be easily cleaned without removing them. The recesses in the internal wall of the tunnel actually permit an excellent overall washing of this tunnel-doctor unit. The dye pads located there can for example be rinsed through by a water jet from a nozzle (water pressure over 10 b). The guide part with the tunnel can be housed in vertically adjustable manner using an automatic vertical adjustment device vis-a-vis the dye tube to which it is advantageously secured, so that an automatic alignment of the roll doctor results. The roll doctor is thus functionally independent vis-a-vis the dye preparation. This represents an advantage compared with known guide apparatuses which still require a precise adjustment as otherwise slippage problems arise with the doctor roll. The

tunnel is, as mentioned previously, suspended movable in vertical direction. It is possible to change the roll diameter, which can be carried out in a short space of time. Typical smallest roll diameters are of the order of 6 mm, the larger roll diameters 25 mm, but other roll diameters are of course also possible.
The roll doctor itself can have a smooth cylindrical external surface, but also a milled external surface. The tunnel, being a part subject to wear, can be of exchangeable design.
Further advantages and details of the invention will be explained in more detail using the following description of the figures.
Fig. 1 shows a dye tube of an apparatus according to the invention together with a
side view of a roll doctor guided in a tunnel,
Figs. 2a, 2b and 2c show sections along line A-A of Fig. 1 with varying distances
between dye tube and web,
Fig. 3 shows a cross-section through the guide body and the roll doctor in the area of
the guide points, resting against the outside of the roll doctor, of the tunnel
Fig. 4 shows a section parallel thereto, but between two guide points where the
tunnel wall is at distance from the roll doctor,
Fig. 5 shows a perspective representation of the end section of a guide body with a
roll doctor housed therein,
Fig. 6 shows the insertion of the roll doctor into the guide body of another
embodiment,
Fig. 7 shows a view from below of this embodiment.
Fig. 1 shows a customary dye tube for feeding dye into the inside of a rotation screen which is not shown here for reasons of clarity. From the dye tube, the dye emerges onto the inside of the rotation screen where it is pressed through the screen by the roll doctor 2, the roll doctor 2 being guided essentially rotatable over its entire length in the tunnel of a guide body 3. The guide body 3 together with roll doctor 2 essentially forms a unit which is housed at the dye tube 1 vertically movable in the direction of the double arrow.
Sections A-A of Fig. 1 according to Figs. 2a, 2b and 2c show the dye tube 1 and the roll doctor 2 housed rotatable in the tunnel 5 of the guide body 3. This roll doctor 2 rests against the inside of a rotary screen arranged between web 7 and roll doctor 2,

and presses the dye through the rotary screen onto the web 7. The roll doctor 2 is attracted during printing in per se known manner by a magnet 8 located beneath it. The guide body 3 together with roll doctor 2 is housed vertically movable at the dye tube 1 so that no precise adjustment of same is required in order to guarantee a precise resting of the roll doctor 2 against the inside of the rotary screen.
This vertical adjustment is realized by securing the guide body 3 for the roll doctor 2 to a slide 6 which is housed displaceable in a holder 9 fixed in the dye tube.
According to the invention, the tunnel 5 does not have a constant diameter over its whole length in the inside of the guide body which is preferably made from plastic, whilst the metallic roll doctor 2 does. It is cylindrical (in special cases it is also milled). This results in the situation shown in Figs. 3 and 4 where the guide body rests against the roll doctor 2 only at specific guide points or ribs 10, whilst close by it is at a distance d from the roll doctor 2 between two such guide points 10. Here, therefore, between roll doctor 5 and the tunnel wall 5a of the guide body 3, the tunnel has a gap which allows a penetration of the dye pad. As a result of this measure, the friction between roll doctor and guide body is reduced so that the roll doctor rotates well. Nonetheless over the entire length of the roll doctor the guide body forms an excellent guide of same because the supporting points or guide points 10 can be arranged at a short distance from one another, for example between 6 mm and 25 mm. The distance of the tunnel wall from the roll doctor 2 between these supporting or guide points 10 is preferably between 0.5 mm and 3 mm.
The guide body 3 containing the tunnel 5 is preferably constructed in one piece from plastic and encloses the roll doctor as a whole at an angle range of over 180°, as is shown for example in Fig. 4. Thus the roll doctor 2 cannot drop downwards but according to the invention can nonetheless project out of the guide body 3 in the direction of the screen in order to be able to fulfil its roll doctor function and press the dye through the screen.
The housing of the roll doctor 2 in the tunnel 5 of the guide body 3 can also be seen from the perspective view of Fig. 5. It will be seen that the guide points 10 are developed as rib-like projections of the tunnel walls, each resting in linear manner against the external wall of the roll doctor 2. The tunnel wall has concave indentations 11 between these guide points so that there is a gap there between the tunnel wall and the outside of the roll doctor 2.

In the case of the embodiment according to Figs. 6 and 7, the external shape of the guide body 3 is rounded. The tunnel structure and the roll doctor 2 correspond however to the previous figures. Again, there are only rib-like projections 10 on the inside of the tunnel 5 which rest against the outside of the roll doctor spaced apart, whilst concave indentations are provided between them which form a gap between roll doctor 2 and guide body 3 so that a dye pad can be transported through here. This also makes for easy cleaning.



Patent Claims:
1. Apparatus for the application of dye to a web with a screen and a roll doctor for pressing the dye through the screen onto the web, the roll doctor (2) being guided rotatable - preferably over its whole length - in a tunnel (5) of a guide body (3), the roll doctor projecting with a part of its circumferential surface over the tunnel (5) on a longitudinal slit facing the screen (6), characterized in that the tunnel wall (5a) is constructed such that it rests against the outside of the roll doctor (2) only at several guide points (10) spaced apart in longitudinal direction of the tunnel, whilst between these guide points (10) it runs at a distance (d) from the roll doctor (2).
2. Apparatus according to claim 1, characterized in that the guide points are developed as rib-like projections (10) of the tunnel wall (5a) and each rests essentially in linear manner against the external wall of the roll doctor (2).
3. Apparatus according to claim 1 or 2, characterized in that the tunnel wall (5) has concavely arched indentations (11) between the guide points (10).
4. Apparatus according to one of claims 1 to 3, characterized in that the tunnel wall rests against the guide points (10) overall at an angle range of over 180° on the outside of the roll doctor (2) - preferably essentially smoothly running.
5. Apparatus according to one of claims 1 to 4, characterized in that the distance between the guide points (10) in longitudinal direction of the tunnel is between 6 mm and 12 mm, preferably between 5 mm and 1 cm.
6. Apparatus according to one of claims 1 to 5, characterized in that the maximum distance of the tunnel wall (5a) from the roll doctor (2) between the guide points is between 0.5 mm and 3 mm.
7. Apparatus according to one of claims 1 to 6, characterized in that the guide body (3) containing the tunnel (5) is developed in one piece.
8. Apparatus according to one of claims 1 to 7, characterized in that the guide body (3) containing the tunnel (5) is made of plastic, the tunnel preferably being milled out.

9. Apparatus according to one of claims 1 to 8, characterized in that the roll doctor (2) has a cylindrical, preferably hard-chromium-plated external surface and is preferably made of metal.
10. Apparatus according to one of claims 1 to 9, characterized in that the guide body (3) containing the tunnel (5) is preferably housed detachable at the dye tube (1) to feed the dye.
11. Apparatus according to one of claims 1 to 10, characterized in that the guide body (3) containing the tunnel (5) is housed essentially in vertically adjustable manner or movable perpendicular to the web (7).
12. Apparatus according to one of claims 1 to 11, characterized in that the tunnel (5) is constructed such that the dye paste adhering to the roll doctor (2) is returned into the application front, i.e. into the dye sump located in front of the roll doctor.
13. Apparatus according to one of claims 1 to 12, characterized in that a magnet (8) for attracting the roll doctor (2) against the screen (6) is arranged on the opposite side of the web (7).

14. Apparatus for the application of dye to a web substantially as herein described with reference to the accompanying drawings.



Documents:

117-chenp-2003-abstract.pdf

117-chenp-2003-claims duplicate.pdf

117-chenp-2003-claims original.pdf

117-chenp-2003-correspondnece-others.pdf

117-chenp-2003-correspondnece-po.pdf

117-chenp-2003-description duplicate.pdf

117-chenp-2003-description(complete)original.pdf

117-chenp-2003-drawings.pdf

117-chenp-2003-form 1.pdf

117-chenp-2003-form 26.pdf

117-chenp-2003-form 3.pdf

117-chenp-2003-form 5.pdf

117-chenp-2003-other-documents.pdf

117-chenp-2003-pct.pdf

abs-117-chenp-2003.jpg


Patent Number 204241
Indian Patent Application Number 117/CHENP/2003
PG Journal Number 26/2007
Publication Date 29-Jun-2007
Grant Date 13-Feb-2007
Date of Filing 20-Jan-2003
Name of Patentee SHRI. PETER ZIMMER KEG
Applicant Address Untere Sparchen 54 A-6330 Kufstein
Inventors:
# Inventor's Name Inventor's Address
1 ZIMMER, Peter Untere Sparchen 54 A-6330 Kufstein.
PCT International Classification Number B05C11/02
PCT International Application Number PCT/AT01/00241
PCT International Filing date 2001-07-18
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 A 1256/2000 2000-07-19 Austria