EP2832555B1

EP2832555B1 - Support device for printing plates

Info

Publication number: EP2832555B1
Application number: EP14178952.9A
Authority: EP
Inventors: Michele Tosti; Fabrizio Pitacco
Original assignee: Protec Surface Technologies SRL
Current assignee: Protec Surface Technologies SRL
Priority date: 2013-07-29
Filing date: 2014-07-29
Publication date: 2015-09-02
Anticipated expiration: 2034-07-29
Also published as: ES2551436T3; EP2832555A1; ITMI20131266A1

Description

The present invention relates to a support device for printing plates of the type as recited in the preamble of Claim 1.
In particular, the invention relates to a specific support device suitable for use in the production of plates for chalcography, that is to say plates on which the design to be printed is etched or engraved or otherwise cut.
As is known in the prior art, in order to create such plates a cast must first be made to obtain the negative of the design to be printed and this cast must then be coated with layers of silver and nickel.
In detail, first the cast is created by etching a base plate, usually made of polyamide or Kapton^®, for example using laser technology, to produce a negative of the images and the words to be printed.
When this has been done, the cast is placed in a device in which a chemical deposition process is performed in order to create a first layer, usually in silver, to coat the surface of the cast with said negative of the image.
At this point, the plate is placed in a second device in which a metallic nickel layer is deposited over the layer of silver, by means of a galvanic deposition process.
The nickel layer is then separated from the silver layer and from the cast, accreted and, lastly, coated with a layer of material with a high surface hardness, usually hard chromium.
US-B1-6 170 396 teaches a support device for printing plates.
The prior art solution mentioned above has several significant drawbacks.
A first drawback lies in the fact that the galvanic processes involve the use of galvanic baths which are associated with problems in terms of the safety of the operator and disposal of the industrial waste that is generated, which is particularly difficult and expensive and has a significant environmental impact.
A further drawback of the printing plates produced in this way consists of the fact that they are not of a uniform thickness over the entire surface of the plate.
The drawbacks described above have been overcome by replacing the galvanic processes with high-vacuum processes.
However, such high-vacuum processes have some additional drawbacks.
They are performed with the plates rotating or translating. The plates therefore have to be supported to prevent them from assuming incorrect positions and, in particular, to ensure the maintenance of the correct position and, thus, a uniform and optimal deposition of the layer of nickel.
A further drawback lies in the difficulty of creating a support that can be secured to the plates without covering the print design and so is able to guarantee its correct coating.
For these reasons, said support is extremely important.
In this situation the technical purpose of the present invention is to devise a support device for printing plates that substantially overcomes the drawbacks mentioned above and, in particular, permits the coating of printing plates using the high-vacuum deposition method.
Within the scope of said technical purpose an important aim of the invention is to provide a support device that makes it possible to have printing plates comprising layers created using high-vacuum processes.
The technical purpose and specified aims are achieved with a support device for printing plates as claimed in the appended Claim 1.
Preferred embodiments are described in the dependent claims.
The characteristics and advantages of the invention are clearly evident from the following detailed description of a preferred embodiment thereof, with reference to the accompanying drawings, in which:

Fig. 1 shows a support device according to the invention;
Fig. 2 shows a detail of the support device;
Fig. 3a shows a plate to be arranged on the support device according to the invention;
Fig. 3b shows a plate to be arranged on the support device; and
Fig. 4 illustrates a portion of the support device according to the invention.

With reference to said drawings, reference numeral 1 globally denotes the support device according to the invention.
It is suitable to be used to create printing plates 10 and, in detail, plates for security printing comprising a base layer 11 having an etched surface 11a comprising etchings or the like to be printed such as, for instance, those on banknotes, stamps, documents or other security printing products; and an outer coating 12 made of a hard-wearing material and, preferably of a material selected from among chromium, zirconium or titanium or the nitrides or carbonitrides thereof, and covering said etched surface 11 a so as to define the printing surface 10a substantially reproducing the etchings present on the etched surface 11 a.
The support device 1 comprises a support 20 defining a main axis of extension 20a preferably parallel to the gravitational gradient, and a substantially prismatic overall profile; attachments 30 suitable to engage with the opposite rims 11b of the base layer 11 surrounding the etched surface 11a; stops 40 suitable to prevent a relative movement between the base layer 11 and the attachments 30; and hooks 50 suitable to releasably secure the attachments 30 to the support 20 in correspondence with the overall profile.
The support 20 comprises at least one base plate 21 and, preferably, two base plates 21 substantially perpendicular to the axis 20a and defining the overall profile of the device 1; and at least one support body 22 suitable to substantially position itself between the plates 21 so as to define a mutual distance between the base plates 21 substantially at least equal to and, appropriately, substantially more than one of the dimensions of the etched surface 11 a, i.e. of the width or length of said etched surface 11 a.
Additionally, the support 20 may comprise at least one intermediate plate 23 arranged between the base plates 21 and suitable to increase the structural rigidity of the support device 1 and to define additional anchoring points of the plates 10 to the support 20.
Advantageously, the plates 21 and 23 are substantially circular in shape with their axis substantially coinciding with the axis 20a so as to define a substantially prismatic, circular-based overall profile, i.e. a cylinder-shaped profile of the support device 1.
The support body 22 has an axis of extension that substantially coincides with the axis 20a and has a smaller cross-section than the plates 21 and 23 so that practically the entire perimeter of the plates 21 and 23 is overhanging in relation to said support body 22.
In particular, it comprises profiles 22a having an axis of extension substantially parallel to the axis 20a and arranged along the perimeter of a circumference centred on the axis 20a having a radius smaller than that of the plates 21 and 23.
Arranged along the perimeter of the plates 21, the support device 1 has at least a pair of attachments 30 suitable to allow the etched surface 11 a to be arranged substantially parallel to the axis 20a and, in particular, to allow the tips of the surface 11 a to be arranged substantially at the same distance from the main axis of extension 20a.
Appropriately, the support device 1 comprises a plurality of pairs of attachments 30 suitable to permit a plurality of base layers 11 to be attached to the support device 1 by arranging their etched surfaces 11 a substantially parallel and at the same distance from the main axis of extension 20a.
Each attachment 30 comprises at least one slit 31 suitable to internally house at least a portion of a rim 11 b and extending substantially parallel to the axis 20a.
Preferably, the attachments 30 consist of rods characterised by a length of not less than the length of the rims 11 b and provided with slits 31 extending at least the length of said rims 11 b.
Joined to the attachments 30, the support device 1 is provided with the stops 40 suitable to prevent a relative movement between the base layer 11 and the attachments 30.
For that purpose, the stops 40 are suitable to engage with the base layer 11 in correspondence with the rims 11 b and the slits 31 so as not to interfere with the deposit of particles and, thus, the creation of the outer coating 12 on at least the etched portion of surface 11 a. Said stops 40 comprise screws engaged in holes obtained in proximity to the rims 11 b and along the slits and/or stop elements suitable to prevent the relative sliding between the slits 31 and the base layer 11 along at least the axis 20a.
Lastly, to enable the base layer 11 to be secured to the support device 1 in a convenient and practical manner, the device 1 is provided with hooks 50 suitable to releasably connect, preferably by means of a snap engagement, the attachments 30 to the support 20 in correspondence with the overall profile.
In particular, said hooks 50 are arranged in correspondence with the ends of the attachments 30 and permit said attachments to be secured in correspondence with the profile of the base plates 21.
They thus comprise at least a first body integral with the attachment 30 in correspondence with one end thereof and defining a seat 51 suitable to internally house and, thus, to snap engage with an edging 20b obtained in correspondence with the outer perimeter of the support 20 and, in particular, of the two plates 21.
The edgings 20b protrude from the plates 21 in a direction substantially parallel to the preferred axis of extension 20a so as to permit the seat 51 to engage with it by means of a translation substantially parallel to the main axis of extension 20a and, in detail, to engage with it substantially due to the force of gravity.
The edgings 20b conveniently protrude in the same direction so as to permit their simultaneous engagement with the seats 51.
The support device 1 is suitable for use in an innovative high-vacuum deposit device capable of creating a coating 12 with a thickness of substantially less than 10 µm by means of a high-vacuum deposition process.
Preferably, the deposit device is suitable for creating the coating 12 by means of a high-vacuum deposition process using the PVD or PE CVD or other similar technique.
Said device comprises, in addition to the support device 1, a container 100 defining said inner chamber suitable to contain the support device 1; a delivery apparatus suitable to deliver into the inner chamber and, thus, deposit on the printing plates 10, the particles, preferably of a material chosen from among chromium, zirconium or titanium or the nitrides or carbonitrides thereof, which form the coating 12; an apparatus for creating a vacuum, for example a vacuum pump, suitable to substantially create a vacuum in the inner chamber; a movement device suitable to move and, in particular, to rotate the support device 1 and the plates 10 along an axis of rotation so as to guarantee the uniform distribution of the particles and, thus, the formation of a substantially uniform coating 12. Said axis of rotation is preferably substantially parallel to the main axis of extension 20a.
The use of a support device and the functioning of a high-vacuum deposit device described above in a structural sense, are as follows.
First, a plurality of nickel base layers 11 are prepared, by performing the galvanic electroforming process described.
The base layers 11 are then secured to the support device 1.
In detail, opposite rims of the layer 11 are inserted in the slits 31 and then secured to the attachments 30 by means of the stops 40.
The base layer is then bent so as to obtain a curvature that is substantially the same as that of the base plates 21 and so that the etched surface 11 a defines the outer surface of the curvature.
Next, the layer 11 is secured to the support device 1 along the outer perimeter of said support device 1 inserting portions of the edging 20b in the seats 51 so that the etched surface 11 a is facing the opposite direction to the axis 20a and substantially parallel to said axis 20a thus substantially defining the overall profile of the support device 1.
Once this has been done, the support device 1 is inserted inside the chamber and arranged so that the axis 20a substantially coincides with the axis of rotation of the unit.
The vacuum apparatus substantially creates a vacuum in the inner chamber; the movement unit turns the support device 1 and the bodies 11 about the preferred axis of extension 20a and, at the same time, the delivery apparatus feeds the particles that form the coating 12 into the chamber 110a and thus deposits them on the etched surfaces 11 a.
When the deposition of the outer coating 12 is complete, the plates 10 are removed from the device 1 and are now ready to be used for printing.
The invention achieves some important advantages.
A first important advantage achieved by using the innovative support device 1 consists in the fact that a high-vacuum process is used to create the printing plates, thus eliminating the need for galvanic deposition processes and so reducing the costs of production of the plates 10 and eliminating the problems of safety and of having to deal with the industrial waste products typically associated with such prior art processes, making it possible to produce a plate with a low environmental impact and respecting the environment.
Another important advantage lies in the fact that with the support device 1, the use of a high-vacuum deposition process to create a coating 12 makes it possible to obtain plates 10 with a highly uniform thickness.
Said advantages are primarily due to the fact that the support device 1 only engages with the plates 11 in correspondence with the rims 11 b and so does not interfere with the deposition of the coating 12 along the etched surface 11 a and, thus, guarantees the formation of said coating 12 along the entire printing surface 10a.
Another advantage lies in the fact that the coating 12 is characterised by an extremely uniform thickness and, thus, by a uniform resistance to wear and physical and mechanical properties.
This advantage is also due to the fact that with the device 1, the surfaces 11 a can be arranged substantially parallel to and, in particular, at an equal distance from the axis 11 and, more in particular, from the axis of rotation defined by the movement unit so as to guarantee the uniformity of the coating 12.
Another no less important advantage lies in the fact that the hooks 50, by means of a snap engagement and, in particular, an engagement between the attachments 30 and support 20 substantially due to the force of gravity, make it possible to guarantee an extremely practical and stable assembly of the support device 1.

Claims

Support device (1) for printing plates (10) comprising a base layer (11) defining an etched surface (11a) and rims (11b) surrounding said etched surface (11 a); said support (1) being suitable to be used for the high vacuum deposit of an outer coating (12) on said etched surface (11a) and being characterised in that it comprises: a support (20) defining a main extension axis (20a) a substantially prismatic overall profile, an edging (20b) of said overall profile protruding in a direction substantially parallel to said main extension axis (20a); attachments (30) comprising slits (31) suitable to contain at least a portion of opposite rims (11b) and having main directions of extension substantially parallel to said main extension axis (20a); stops (40) suitable to prevent a relative movement between said base layer (11) and said attachments (30); and hooks (50) comprising at least one seat (51) integral with said attachments (30) suitable to snap engage to said edging (20b).
Support device (1) as claimed in claim 1, in which said attachments (30) are suitable to constrain said base layer (11) to said support (20) placing said etched surface (11 a) substantially parallel to said main extension axis (20a).
Support device (1) as claimed in one or more of the previous claims, in which said support (20) defines said substantially prismatic, circular-based, overall profile.
Support device (1) as claimed in the preceding claim, in which said attachments (30) are suitable to constrain said base layer (11) to said support (20) placing the tips of said etched surface (11a) substantially at the same distance from said main extension axis (20a).
Support device (1) as claimed in one or more of the previous claims, in which said support (20) comprises two base plates (21) substantially perpendicular to said main extension axis (20a) and defining said overall profile; and at least one support body (22) suitable to substantially position itself between said plates (21) substantially equal to a dimension of said etched surface (11 a).
Support device (1) as claimed in the preceding claim, in which said base plates (21) and said support body (22) have a main extension axis substantially coinciding with said main extension axis (20a); and in which said base plate (21) has a greater cross-section than said support body (22) so that the perimeter of said plates (21) is overhanging in relation to said support body (22).
Support device (1) as claimed in one or more of the claims 6-7, in which said edging (20b) protrudes from said base plates (21) along the perimeter of said base plates (21).