Title of Invention

PRINTING MACHINE CYLINDER, ESPECIALLY A BACK-PRESSURE CYLINDER FOR A SHEET-FED ROTARY PRINTING MACHINE

Abstract A printing machine cylinder, especially a back-pressure cylinder for a sheet-fed rotary printing machine, having a basic cylinder body, which is rotatably mounted in the housing of the printing machine and is covered by a film having a large number of openings, characterized in that the circumferential surface of the basic cylinder body has recesses formed in it, which accommodate elements which run over the circumferential surface of the cylinder and have a large number of passage channels, which have a flow connection to the openings in the film and extend from the upper side of the elements to air distributor chambers that can be connected to a suction-air source or blown-air source.
Full Text The invention relates to a printing machine cylinder especially a back-pressure cylinder for a sheet-fed rotary


DE-A 41 26 643 Al discloses a transfer cylinder for a sheet-fed rotary printing machine which has a basic cylinder body formed by four supporting discs, on which a total of three


provision of a transfer cylinder, which is designed as a storage drum and is covered with a porous film, with a suction box which can be moved in order to adapt to different sheet


with blowing or suction openings, may be produced in. a simpler and more cost-effective way.
According to the invention, this object is achieved by the features of clamis 1, 24 and 25.


chambers are formed directly in the basic body of the cylinder/
Fig. 5 shows a Schematic illustration of a preferred embodiment of an inventive printing machine Cylinder, in which the blowing/suction elements are arranged like rows on the circumferential suface of the cylinder and


As is illustrated in Fig. 2 in the enlarged sectional view through the basic body 8 of the inventive printing machine cylinder 1, recesses 20 are made into the basic body 8 from the circumferential surface 18, it being possible/ for example/ for said recesses to be milled into the basic body 6 within the context; of" rough machining following its casting. However, in the same way, provision may also be made for the basic structure oil the recesses 20 or chambers 26 already t6 be provided in the circumferential surface 18 of the basic body 8 during the casting of the basic body 8 and for these then to be re-machined if necessary. The recesses 20 accommodate, inventive elements 22, in which there are formed a large number of passage channels 24, which extend.from the upper side, of the, eleroents 22 to an air distributor chamber 26 placed within the periphery of the cylinder 1.
In the case of the embodiment of the invention illustrated in Fig. 2, the air distributor chamber"26 is fomled directly aiS a further recess in,the base of the recess 20 and can be produced, for example./ in the same way as the recess 20, toy milling out the same during the basic machining of the basic cylinder body-8

The air distributor chamber 26 can be Connected via an air feed line 28 t6 a blown-air or suction-air source (not specifically illutrated), it being possible for the flow connection between the blown-ait or suction-air source and the air distributor chamber 26 to be made preferably via one or more valves-30,. illustrated schematically is a block in Fig. 1, and a control device 32 in the form of a known rotary lead-through or a rotary valve.

As illustrated in Fig. 3, in the case of a further embodiment of the invention the air distributor chamber 2 6 can be formed directly as a recfess in the inventive blowing/suction element 22. The air distributor chamber 26 may have, for exaai|5le> a height of a few millimeters, for example 2 mm, and/ in the circumferential direction of the printing machine cylinder 1/ extends by a few millimeters beyond the air feed line 28. In the axial direction, on the other hand/ it is possible for the chamber 26 to extend in some sections underneath one or more of the elements 22 or else even over the entire cylinder width. Further more/ however/ provision may also be made to form the air distributor chamber 26 only locally, underneath a blowing/suction Element 22, for example one of circular, design, as a recess/ for example one of circular shape, in such a way that a plurality of circular air distributor chambers 2 6 are in each case supplied via separate air feed lines 28 with Auction air or blown .air.
The passage channels 24 arranged above the air distributor chamber 26 have, in the preferred embodiment of the invention, a diameter which is considerably smaller than the physical-extent of the air distributor chamber 26 and which, for example may lie in the range between 0.5 mn and 1.5 mm.
As illustrated in"Fig. 4, provision may further be made for the passage channels 24 in the blowing/suction elements 25 "to have a cross sect,ion that widens in the direction of the inventive air distributor chamber 26/ it being possible, in the region of the air distributor chamber 26, for said diameter to be, iPor example, up to three or more times the cross section at the opposite end of the passage channels 24. In the case of suction-air operation of the inventive printing machine;: cylinder 1, this results in a considerably reduced " susceptibility to faults in relation to blockages, which can

be brought about, for example, by paper dust or other particles penetrating into the passage channels 24.
The production of the inventive blowing/suction elements 22, which are preferaJbly produced from the same material as the basic cylinder boi;iy 8, for example from gray cast iron, but may also consist of another pressure-resistant material, for example aluminum, steel or fiber-reinforced plastic, is carried out in an inventive way independently of the machining of the basic cylinder body 8. By this means, the large number of fine passage channels 24 formed in the elements 22 csn advantageously be introduced into the elements 22 with the and of suitable tools,, such as batteries of drills or -suitable laser machining tools, which results in considerable advantages from a production point of view. In this connection, it is also possible to produce the elements 22 " directly from a pressure-resistant, coarsely porous material, in which the passage channels are produced, for example, by-foaming or etching or sintering during the material production- on account of the separate machining of the elements 22, for example in the case of breakage of a drilling tool when drilling the through channels 24, no damage occurS to the consideralbly more expensive-basic cylinder body 8,as is generally the,case during the production of printing machine cylinders in accordance with the prior art, in which the channels are "drilled directly into the circumferential -. surface of the basic cylinder body. In addition, the mabhiiiing time is considerably reduced by the separate machining of the elements 22, since a plurality of elements 22 can be machined at the same time.
After the elements 22 have been machined in the afqrementioned way, separately from the basic cylinder body 8, said elements are inserted into the recesses 20 in the basic cylinder bodv

8, and the basic cylinder body 8 is re-machined in a knovn way by surface grinding or surface turning using suitable tools.. The fastening of the elements 22 in the recesses 20 of the basic cylifader body 8 can in this case be carried out, for example, by ineanaof screws (hot illustrated) or by bonding Or pressing the sameifin. As a result of the; joint fine mafchining of the elements 2-2 together with the basic cylinder body 8, the upper side of th6 elements 22 receives exactly the surface course of the cireumferential surface 18 of the basic cylindfer body 8, as a result of which out-of-roundness in the region of the elements 22/ Or protrusion of the elements 22 beyand the circumferential surface 18 are avoided. CGhaeqUently/ ho V disadvantageous impairment of the prinited image oc;curi$i
Finally, a porous"textured film, for example one disclosed by KP 0 165 477, for example in the form of a glass bead, cloth or of a textured chromium covering, is applied ,to the; circmtLferential sutface 18 of the basic cylinder body :8, said film having, at least in the region above the passage channels 24/ a large number of fine openings 36, through which: depending on the, mode of operation and use of,the inventive cylinder 1, suction air ot blown air passes, as illustrated schematicaily.in Fig. 6. "The cross section of the openings 36 is here considerably smaller than the cross section of the , passage channels :24. The film 34 may, for example , be stretched Over the circumferential isurface 18 Of the basic cylinder body 8 Or else may be bOhded oh and serves to distribute: the compressive forces exerted on the element is 22 uniformly in the region Of the passage channels 24 when an inventive cylinder 1 is being used as a back-pressre cylinder in the press nip,in order to prevent the occurence of impressions of the channels 24 in the printed image.As illustrated in Fig,6 the film 34"may have a surface structure 38 which, in the case of the preferred embodiment of

the invention, comprises interconnected depressions,. which: enable the suction or blown air to be distributed over an area underneath a sheet 16 resting on the film 34 Furthernuore, the film 34 is preferably coated so as to repel ink.
As shown in Fig. 5, in the case of the preferred embodiment of the invention, the recesses 20 in the circumferential surface 18 of the cylinder 1 are designed as grooves 20a/ in which the blowing/suction elements 22 are accommodated in the form of . bars. In this case a plurality of air distributor chambers 56 to which, separately from one another, blown air or suction air can be applied, are arranged along one Of the groove-like recesses 20a. The groove-like recesses 20a may extend both in the circumferential direction and in the axial direction along the circumferential surface 18 of the printing machine cylinder l.
As is shown further in Fig. 5, the blowing/suction elements 22 are preferably arranged in rows on the circumferential surface 18 of the cylinder 1, it being possible for said rows to extend over the circumferential surfaee IS both in the circumfererLtial direction and in the axial direction, However, in the same way provision may also be made for therows 40 to run on the cirdmftlferential surface 18 of the cylinder 1 , essentially in a V shape or in a ray shape. This can, be achieved, for example, in that the rows 40 extending in the axial direction, as seen in the. direction of rotation 42 of the Cylinder 1, have a decreasing length, by which.iSieans, depertdihg an the sheet format to be processed, iri "the case Of small-format sheets l6a, only the blowing/suction elements 2,2 placed in the region of the sheet trailing edge 44a in the center of"the circumferential surface. 18 of the cylinder 1 pick up the small-format sheet 16$ by suction. On the other hand, in the case: of processing large-format sheets 16b, which

generally have a higher weight and are therefore subject to the action of a greater centrifugal force, preferably all the blowing/suction elements 22 on the circumferential surface 18 are activateel in order to apply suction air or blown air to the sheets 16, so that large-format sheets 16b are preferably held on the circuiftferential surface 18 not just in the region of their sheet trailing edge 44b.
As is indicated: by the valves of the valve block 30 in FigĀ» 5, it is possible for the blowing/suetion elements 22 of the axially running rows 40, or their air, distributor chambers 26, to have blown air or suction air applied to them prefeirably in groups, the application taking place as a function of the Sheet format to be processed, in such a way that only the elements 22 placed underneath a sheet 16 being conveyed oh the cylinder have bloiwn air or suction air applied to them. In this case of this embodiment of the invention, preferably all the : elements 22, or their air distributor chambeirs 26: are ; simultaneously connected to the suction-air or blownair source via; the valve block 30 by way of the control device 32 in the form of a;known rotary lead-through.
In the same way, provision may be it made for the axial rows 40, considered; in the circumferential direction, to have suction air applied to them progressively via the control device 32 after the press: nip has been passed or shortly before, this, so , that the transported sheets 16 are progressively drawn on to the circumferential surface of the cylinder 1 and smoothed. "In the same way, the rows 40 of blowing/suction elements,22 Can tiave blown; air or blown air surges, applies to them; progressively, beginning At a specific, predefined rotational angle position," in order to, detach the sheets 16 from the :;ircumferentia.l surface 19.

Especially in the case of using the inventive printing machine cylinder 1 as a back-pressure cylinder in a printing unit arranged upstream of a turning device, it has transpired that it is advantageous. to apply suction air to the elements 22 arranged along an axial row 40, or to their distribution chambers 26, in the region between the press nip and the transfer center line 4 6 to the downstream turniiig druum 14 , (Fig. 1), and to apply blown air to the coriesponding axial rows 40 underneath the sheet trailing edge 44a/ 44b only immediateiy before or immediateiy after the; sheet trailing edge 44a, 44b has been gripped by a gripper device of the turning drum l4,in order- to detach from the circumferehtial surface 18 the sheet; 16 picked up on the latter by suction.


WE CLAIM:
1. A printing machine cylinder, especially a back-pressure cylinder for a sheet-fed rotary printing machine, having a basic cylinder body, which is rotatably mounted in the housing of the printing machine and is covered by a film having a large number of openings, characterized in that the circumferential surface (18) of the basic cylinder body (8) has recesses (20) formed in it, which accommodate elements (22) which run over the circumferential surface (18) of the cylinder (1) and have a large number of passage channels (24), which have a flow connection to the openings (36) in the film (34) and extend from the upper side of the elements (22) to air distributor chambers (26) that can be connected to a suction-air source or blown-air source.
2. The printing machine cylinder as claimed in claim 1, wherein the air distributor chamber (26) is formed in the elements (22).
3. The printing machine cylinder as claimed in claim 1, wherein the air distributor chamber (26) is formed by a further recess made in the basic cylinder body (8).
4. The printing machine cylinder as claimed in any one of the preceding claims,
wherein the recesses (20) are of essentially groove-like design (20a) and the elements
(22) are of essentially bar-like design, and wherein a plurality of air distributor
chambers (26), to which, separately from one another, blown air or suction air can be
applied, are arranged along the groove-like recesses (20a).
5. The printing machine cylinder as claimed in claim 4, wherein the recesses (20a)
extend over the circumferential surface (18) of the printing machine cylinder (1) in the
circumferential direction.

6. The printing machine cylinder as claimed in claim 4, wherein the recesses (20a) extend over the circumferential surface (18) of the printing machine cylinder (1) in the axial direction.
7. The printing machine cylinder as claimed in any one of the preceding claims, wherein the recesses (20, 20a) with the elements (22) are arranged on the circumferential surface (18) essentially in rows (40).
8. The printing machine cylinder as claimed in claim 7, wherein the rows (40) parallel to one another.
9. The printing machine cylinder as claimed in claim 7, wherein the rows (40) run in the axial direction.

10. The printing machine cylinder as claimed in claim 9, wherein the rows (40), as seen in the direction of rotation (42) of the cylinder (1), have a decreasing length.
11. The printing machine cylinder as claimed in any one of claims 7 or 10, wherein the rows (40) run in the circumferential direction.
12. The printing machine cylinder as claimed in any one of claims 7, 10, 11, wherein the rows (40) run in a V shape or in a ray shape.
13. The printing machine cylinder as claimed in any one of claims 7 to 12, wherein the air distributor chambers (26) of a row (40) can have suction air or blown air applied to them jointly via a cormecting line.

14. The printing machine cylinder as claimed in any one of the preceding claims, wherein the air distributor chambers (26) are assigned valves (30), via which the air distributor chambers (26) can be connected individually or in groups to the suction-air source or the blown-air source.
15. The printing machine cylinder as claimed in claim 14, wherein the air distributor chambers (26) have suction air or blown air applied to them as a function of the sheet format (16a, 16b) to be processed, by suction air or blown air being applied only to the elements (22) placed underneath a sheet (16) being conveyed on the cylinder.
16. The printing machine cylinder as claimed in one of the preceding claims, wherein control means (32) are provided to control the blown-air supply or suction-air supply to the air distributor chambers (26).
17. The printing machine cylinder as claimed in claim 16, wherein all the air distributor chambers (26) can be connected simultaneously, via the control means (32), to the suction-air source of blown-air source.
18. The printing machine cylinder as claimed in any one of the preceding claims, wherein the passage channels (24) in the elements (22) have a cross section that widens in the direction of the air distributor chamber (26).
19. The printing machine cylinder as claimed in any one of the preceding claims,
wherein the surface of the film (34) has a structure (38).

20. The printing machine cylinder as claimed in claim 19, wherein the structure (38) comprises interconnected depressions, which enable the suction or blown air to be distributed over an area underneath a sheet (16) resting on the film (34).
21. The printing machine cylinder as claimed in any one of claims 16 to 20, wherein this is designed as a back-pressure cylinder (1) arranged upstream of a turning device (12), and wherein, during perfecting operation, the control means (32) connect the air distributor chambers (26) in the region between the press nip and the transfer center line (46) between the back-pressure cylinder (1) and a downstream sheet-conveying cylinder (14) to the suction-air source, in order to hold the sheets (16) on the circumferential surface (18) of the cylinder (1).
22. The printing machine cylinder as claimed in any one of claims 16 to 21, wherein, during perfecting operation, the control means (32) cormect the air distributor chambers (26) in a transition region, which lies directly upstream or directly downstream of the transfer center line (46) and in which the trailing edge (40a, 40b) of the sheet (16, 16a, 16b) is taken over by a gripper device of the downstream sheet-conveying cylinder (14), to the blown air source.
23. The printing machine cylinder as claimed in any one of claims 16 to 22, wherein, as seen in the direction of rotation (42) of the cylinder (1), during perfecting operation, the control means (32) connect the air distributor chambers (26) in the region between the press nip and the transfer center line (46) and the press nip between the cylinder (1) and a downstream sheet-conveying cylinder (14) to the blown-air source, in order to detach the sheets (16) from the circumferential surface (18) of the cylinder (1).

24. A method of producing a printing machine cylinder, especially a back-pressure
cylinder of a sheet-fed rotary printing machine, which comprises the following
method steps:
providing a basic cylinder body, introducing recesses into the circumferential surface of the basic body, introducing one or more air distributor chambers into the recesses, introducing one or more air supply bores into the air distributor chambers, inserting a large number of elements having passage channels into the recesses, finely machining the cylinder circumferential surface as a whole, and applying a film having openings to the circumferential surface of the cylinder.
25. A method of producing a printing machine cylinder, especially a back-pressure
cylinder of a sheet-fed rotary printing machine, which comprises the following
method steps:
providing a basic cylinder body, introducing recesses into the circumferential surface of the basic body, introducing one or more air supply bores into the recesses, inserting elements having a large number of passage channels and one or more air distributor chambers into the recesses, finely machining the cylinder circumferential surface as a whole, and applying a film having openings to the circumferential surface of the cylinder.

Documents:

2597-mas-98 abstract.pdf

2597-mas-98 claims-duplicate.pdf

2597-mas-98 claims.pdf

2597-mas-98 correspondence-others.pdf

2597-mas-98 correspondence-po.pdf

2597-mas-98 description (complete)-duplicate.pdf

2597-mas-98 description (complete).pdf

2597-mas-98 drawings.pdf

2597-mas-98 form-19.pdf

2597-mas-98 form-2.pdf

2597-mas-98 form-26.pdf

2597-mas-98 form-4.pdf

2597-mas-98 form-6.pdf

2597-mas-98 petition.pdf


Patent Number 215907
Indian Patent Application Number 2597/MAS/1998
PG Journal Number 13/2008
Publication Date 31-Mar-2008
Grant Date 05-Mar-2008
Date of Filing 17-Nov-1998
Name of Patentee HEIDELBERGER DRUCKMASCHINEN AKTIENGESELLSCHAFT
Applicant Address KURFURSTEN-ANLAGE 52-60, D-69115 HEIDELBERG,
Inventors:
# Inventor's Name Inventor's Address
1 WILLI BECKER UNTER DER STEIGE 8, 69245 BAMMENTAL,
2 DR ANDREAS FRICKE ALTE DIELBACHER STR,58 A,69412 EBERBACH,
PCT International Classification Number B41F 21/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 19756942.0-27 1997-12-22 Germany