STRUCTURAL UNDERBLANKET UNIT FOR BLANKET CYLINDERS OF PRINTING MACHINES AND PROCESS FOR ADJUSTING A DISTANCE OF A BLANKET FROM A WALL OF A BLANKET CYLINDER

Abstract

A structural underblanket unit (10) for blanket cylinders (100) of printing machines, comprising a first layer (11) made of rubber, a second layer (12) made of polyester and a third layer (13) made of fabric. The layers (11, 12, 13) are solidly bonded to one another so as to define a multilayer structural unit (10) having an overall transversal thickness (S) corresponding to the sum of the transversal thicknesses (S11, S12, S13) of said layers, the order of bonding of said layers being any whatsoever. A process for adjusting a distance of a printing blanket (101) from a wall (102) of a blanket cylinder of a printing machine.

Claims

1. A structural underblanket unit (10) for blanket cylinders (100) of printing machines, comprising: a first layer (11) made of rubber and having a predefined transversal thickness (S11); a second layer (12) made of polyester and having a predefined transversal thickness (S12); a third layer (13) made of fabric and having a predefined transversal thickness (S13), said layers (11, 12, 13) being solidly bonded to one another so as to define a multilayer structural unit (10) having an overall transversal thickness (S) corresponding to the sum of the transversal thicknesses (S11, S12, S13) of said layers, the order of bonding of said layers being any whatsoever, wherein said structural unit (10) has no printing blanket, and configured distinct and independently removable from a corresponding blanket with which, in use, it is adapted to collaborate.

2. The structural unit according to claim 1, wherein the second layer (12) made of polyester is interposed between and bonded to said first (11) and third (13) layers.

3. The structural unit (10) according to claim 2, wherein the first layer (11) made of rubber is configured to rest upon a bottom surface of a printing blanket (101), whilst the third layer (13) made of fabric is configured to rest upon a wall (102) of a blanket cylinder, in such a way that said structural unit (10), in use, is interposed between the printing blanket (101) and the wall (102) of the cylinder.

4. The structural unit (10) according to claim 1, wherein the value of the overall transversal thickness (S) of the structural unit (10) may be between about 0.55 mm [millimeters] and about 1.45 millimeters.

5. The structural unit (10) according to claim 1, wherein the value of the transversal thickness (S11) of the first layer (11) made of rubber is greater than about 0.1 mm [millimeters].

6. The structural unit (10) according to claim 1, wherein the value of the transversal thickness (S12) of the second layer (12) made of polyester is greater than about 0.1 millimeters.

7. The structural unit (10) according to claim 1, wherein the value of the transversal thickness (S13) of the third layer (13) made of fabric is greater than about 0.15 millimeters.

8. The structural unit (10) according to claim 1, wherein each of the transversal thicknesses has a tolerance of 0.02 millimeters relative to a nominal value.

9. A process for adjusting a distance of a printing blanket (101) from a wall (102) of a blanket cylinder of a printing machine, comprising the steps of: preparing a structural unit (10) according to claim 1; placing the structural unit (10) between the printing blanket (101) and the wall (102) of the blanket cylinder.

10. The process according to claim 9, further comprising the following steps: preparing a structural unit (10) according to claim 2; applying the first layer made of rubber to a bottom surface, or back, of the printing blanket; applying the third layer made of fabric on a wall of a blanket cylinder.

11. A printing machine comprising a blanket cylinder provided with a blanket, wherein the structural unit according to claim 1 is interposed between the blanket and a wall of the blanket cylinder.

Description

DESCRIPTION OF THE DRAWINGS

[0049] Additional features and advantages of the present disclosure will emerge more clearly from the indicative, and hence non-limiting, description of one or more configurations of the present disclosure, as illustrated in the appended drawings.

[0050] FIG. 1 illustrates a perspective view of a structural unit according to the present disclosure.

[0051] FIG. 2 illustrates a sectional view of a blanket cylinder provided with the structural unit shown in FIG. 1.

[0052] It should be understood that the drawings serve solely to clarify, in combination with the description, the inventive principles at the basis of the present disclosure.

DETAILED DESCRIPTION

[0053] In the present description, the reference to one configuration or similar expressions means that a particular feature, structure or characteristic described in connection with the configuration is included in at least one configuration of the present description. Appearances of the phrases in one configuration, and similar expressions may, albeit not necessarily, all refer to the same configuration. Analogously, the use of the term implementation indicates an implementation having a particular feature, structure or characteristic described in connection with one or more configurations of the present description; in the absence, however, of an explicit correlation indicating otherwise, an implementation can be associated with one or more configurations.

[0054] With particular reference to FIG. 1, a structural unit, or pack, has been denoted in its entirety by the number 10.

[0055] The pack 10 is composed of a first layer 11 made of rubber, which may be nitrile rubber, also known as Buna-N or Perbunan. Furthermore, the rubber may have a shore A hardness between 71 and 77. The pack 10 is further composed of a second layer 12 made of polyester and a third layer 13 made of fabric.

[0056] The layers 11, 12, 13 are solidly bonded to one another, so that the pack 10 is multilayer and has an overall transversal thickness S corresponding to the sum of the transversal thicknesses S11, S12, S13 of the aforesaid layers 11, 12, 13. In other words, the layers 11, 12, 13 are bonded to one another in such a way as to define a single multilayer body, i.e. the above-mentioned pack 10.

[0057] The second layer 12 made of polyester is interposed between the first layer 11 made of rubber and the third layer 13 made of fabric and is bonded to them. Advantageously, the polyester layer 12, being an intermediate layer, acts as a connecting interface, as it has physiochemical characteristics making it easily connectable both to the first layer 11 made of rubber and the third layer 13 made of fabric.

[0058] In accordance with further unillustrated variant configurations, there is envisaged the possibility that the layers are bonded together according to an order different from the one illustrated in FIG. 1; for example, the fabric layer could be interposed between the rubber layer and the polyester layer. In this case, the polyester layer is configured to rest upon the wall of the blanket cylinder. Other combinations of layers are clearly possible without going beyond the inventive concept of the present disclosure.

[0059] With particular reference to FIG. 2, the first layer 11 made of rubber is configured to rest upon a bottom surface of a blanket 101, whereas the third layer 13 made of fabric is configured to rest upon a wall 102 of a blanket cylinder 100, so that the pack 10 is interposed, in use, between the blanket 101 and the wall 102 of the cylinder.

[0060] The blanket cylinder 100 rotates about an axis A according to known methods not further described.

[0061] The fabric used to make the third layer is selected from among cotton, a synthetic material (e.g. nylon) or a cotton and synthetic blend.

[0062] According to a one aspect, the pack 10 has an overall transversal thickness S between about 0.55 mm and about 1.45 mm. In accordance with alternative variant configurations, the transversal thickness of the pack can have values up to 2 mm or higher.

[0063] According to a possible implementation, the value of the transversal thickness S11 of the first layer 11 made of rubber is greater than about 0.1 mm and may be between about 0.12 and about 0.72 mm.

[0064] In accordance with a further implementation, the second layer 12 made of polyester has a transversal thickness S12 greater than about 0.1 mm and may be between about 0.19 and about 0.35 mm.

[0065] According to another implementation, the value of the transversal thickness of the third layer 13 made of fabric is greater than about 0.15 mm and may be between about 0.2 and about 0.4 mm.

[0066] For each of the above transversal thicknesses S, S11, S12, S13, there is envisaged a tolerance of 0.02 mm relative to a nominal value.

[0067] A possible method for producing the pack 10 (FIG. 1) may include the following steps:

[0068] (1) preparing a first layer made of rubber;

[0069] (2) preparing a second layer made of polyester, for example, having a Trichloroacetic Acid (TCA) treatment on at least one of its surfaces, so as to facilitate adhesion with the rubber layer;

[0070] (3) preparing a third layer made of fabric;

[0071] (4) bonding the fabric layer to the polyester layer, for example by gluing or knitting;

[0072] (5) heating the rubber layer;

[0073] (6) applying the rubber layer on top of the polyester layer.

[0074] In accordance with an alternative implementation of the production method, it is envisaged that the order of execution of the steps of heating the rubber layer and applying it on the polyester layer is inverted, that is, first the rubber layer is applied on the polyester and then it is heated. The heating may take place with the passage of air or by irradiation with infrared radiation.

[0075] According to a variant of implementation of the production method, there is envisaged the possibility that the order of bonding the layers is any whatsoever. In this case, for example, it is envisaged that the rubber layer is applied on the fabric layer, after the latter was previously bonded to the polyester, for example by gluing or knitting. In this case, the fabric layer is interposed between the rubber layer and the polyester layer, the latter thus being configured to rest upon the wall of the blanket cylinder.

[0076] With particular reference to FIG. 2, a process for adjusting a distance of a printing blanket from a wall of a blanket cylinder of a printing machine will now be described.

[0077] In particular, the process relates to an offset printing machine provided with a so-called blanket cylinder provided with a blanket, generally made of rubber or other materials suitable for the printing process.

[0078] The process may include the steps of:

[0079] i) preparing a first layer 11 made of rubber and having a predefined transversal thickness S11;

[0080] ii) preparing a second layer 12 made of polyester and having a predefined transversal thickness S12;

[0081] iii) preparing a third layer 13 made of a fabric and having a transversal predefined thickness S13;

[0082] iv) solidly bonding said layers 11, 12, 13 to one another according to any order whatsoever in order to obtain a multilayer structural unit 10 having an overall transversal thickness S corresponding to the sum of the transversal thicknesses S11, S12, S13 of said layers;

[0083] v) placing the structural unit 10 between the blanket 101 and the wall 102 of the blanket cylinder 100.

[0084] The second layer 12 made of polyester may be bonded to the remaining first and second layers 11, 13 in such a way as to be interposed between them.

[0085] In other words, the structural unit 10 is made in a single body and is interposed between the blanket 101 and the wall 102 of the blanket cylinder 100. In this manner, the structural unit 10 is easily removable from its positioning in order to be replaced in the event of wear or in the event that the thickness to be interposed between the blanket 101 and the blanket cylinder 100 is changed.

[0086] Any modifications or variants which, in the light of the description, are evident to the person skilled in the art, are considered to fall within the scope of protection established by the present disclosure, according to considerations of technical equivalence.