MXPA96000389A

MXPA96000389A - Method and apparatus for handling print leaf material

Info

Publication number: MXPA96000389A
Application number: MXPA/A/1996/000389A
Authority: MX
Inventors: Warren Demoore Howard; Andrew Branson John
Original assignee: Demoore Howard W
Priority date: 1995-01-27
Filing date: 1996-01-26
Publication date: 1998-04-01

Abstract

The present invention relates to a support cylinder for guiding a freshly processed substrate material between the printing units or at the delivery end of a printing press, it is provided with a semiconductor covering of the base, with low coefficient of friction , to support and guide the newly processed substrate material without ink dripping or without causing indentations on the substrate surface. The radially projecting surface portions of the semiconductor covering of the base define points of electrostatic precipitation, and reduce the surface area available for frictional coupling. The low friction and semiconductor properties of the base covering allow free movement of the newly processed substrate in relation to the surface of the support cylinder. The electrostatic charges carried by the newly processed substrate are discharged through the semiconductor covering of the base towards the support cylinder, thus eliminating the attraction of electrostatic draping between the newly processed substrate and the support cylinder.

Description

METHOD AND APPARATUS FOR HANDLING 'PRINTED LEAF MATERIAL The present invention relates to improvements to transfer cylinders to prevent runoff and debris from freshly printed sheet material in a printing press. In the operation of a multi-unit rotary offset printing press, the newly printed sheets are transported by transfer devices from one printing unit to another, and then delivered to a sheet stacker. Sheet transfer devices are known by different names, including transfer cylinders, support rollers, delivery wheels, delivery cylinders, skeleton wheels, transfer drums, support wheels, guide wheels, and the like. The problems of ink marks inherent in the transfer of newly printed sheets have lasted a long time. In order to minimize the contact area between the transfer cylinder and the printed sheet, conventional support wheels have been modified in the form of relatively thin discs having a serrated or saw circumference, referred to as skeleton wheels. However, these thin disc wheels have not overcome the problems of run-off and imprints of the printed surface of the newly printed sheet material, due to the sliding action between the sheet material and the projections or saw teeth. Moreover, attempts to minimize the surface support area in contrast with the sheet material have resulted in actual indentation or hole formation in the material itself. Different efforts have been made to overcome the limitations of thin disc skeleton wheels. One of the most successful solutions has been completely contrary to the concept of minimizing the area of surface contact. This improvement is described and claimed in my United States Patent Number 3,791,644, wherein I provide a substantially cylindrical wheel or roller coated with an improved ink repellent surface formed by a layer of polytetrafluoroethylene (PTFE). During the use of the PTFE coated cylinder the high speed commercial printing press, the surface of the coated cylinder should be washed relatively frequently with a solvent to remove any accumulation of ink. The limitations on the use of the conventional skeleton wheel and the transfer cylinder coated with PTFE have been overcome with a transfer cylinder having an ink repellent and a flexible jacket covering to handle the newly printed sheet material. It is now well recognized and accepted in the printing industry around the world, that the marks and the impressions of the printed sheets are solved by the wet printing of the printed surface against the supporting surface of a transfer cylinder. conventional press, are substantially eliminated by the use of the flexible coating system against the marks, as described and claimed in my United States Patent of North America Number 4,402,267 entitled "Method and Apparatus for Handling Printed Sheet Material", whose description is incorporates this as a reference. That system, which is marketed under the license of Printing Research, Inc. of Dallas, Texas, under the SUPER BLUE® registered somersail, includes a movable cover or sleeve of flexible material, referred to as "flexible sleeve coverage". The flexible jacket covering provides a deformable cushion support for the newly printed side of the sheet, such that any relative movement between the printed sheet and the surface of the transfer cylinder takes place between the surface of the flexible sleeve covering and the surface of the support of the cylinder, in such a way that the marks and the drains of the newly printed surface are substantially reduced. Although the improved SUPER BLUE® transfer cylinder has achieved worldwide commercial success, with continuous use, as is common in many printing operations, after a period of time, there is a slight accumulation of ink on the surface of the flexible samisa covering. Moreover, some printing presses do not have enough tolerance of the cylinder to accommodate the flexible jacket covering. Research and testing has identified the accumulation of an electrostatized charge on the newly printed sheets as a significant factor that tends to impede the completely free movement of the printed sheets as they are pulled around the transfer cylinder. The accumulation of electrostatic charge seems to cause a more rapid accumulation of ink, in such a way that the supporting surface of the transfer cylinder becomes embedd of ink, thus requiring a replacement more frequently. It is believed that the accumulation of electrostatic charge on newly printed sheets is caused by "frictional electricity", which is the transfer of electrons from one material to another as they are compressed or rubbed together. According to one theory, the transfer of an electrostatic charge between two dielectric materials in contact, such as the metal parts of the printing press and a paper or other substrate sheet, is proportional to the difference between their dielectric constants, moving the electrostatic charge from the material that has the lowest dielectric constant to the material that has the highest dielectric constant. Since the metal has a lower dielectric constant compared to paper, an electrostatic charge is transferred to the sheets of paper as a result of frictional contact with the metal parts of the press, as the sheets travel through the press . These transfer cylinders whose transfer surfaces are covered by a natural or synthetic organic resin, for example, as described in my United States Patent Number 4,402,267, have a low friction transfer surface, but also have dielectric properties. electrically insulating that make the base covering of the cylinder become an accumulator of electrostatic charges. That is, the electrical charges that are transferred to the printed sheets are also transferred to the base coat of the electrically insulating, low frictive, underlying dielectric cylinder. As a consequence of this transfer and accumulation of the electrostatic charge, the newly printed sheets tend to hang towards the covering surface of the base of the underlying cylinder, and do not move as freely due to the force of the electrostatic attraction between the material of printed sheet and the base covering of the electrically insulating cylinder.

We have discovered that a sheet transfer can be obtained virtually without runoff, without using a flexible jacket covering as described in United States Patent Number 4,402,267. According to the present invention, the transfer of sheets without draining is performed by covering the base of an elastically semi-semi-hard material having a frictional coefficient which is less than the frisional coefficient of the supporting surface of the transfer cylinder sheet. . The damaging effect of the accumulation of electrostatic charge on newly printed sheets is prevented by interposing a layer or coating of semiconductor material having a low coefficient of friction, which is less than the coefficient of friction of the surface of the transfer cylinder, by which, the electrostatic charges carried by the newly printed sheet material are discharged through the semicondustor layer or cover to the transfer or delivery cylinder. In consesuencia, the accumulation of the electrostatic charges on the semiconductor covering can not be presented, since these loads are conducted immediately from the printed sheet through the semiconductor covering of the base, to the transfer cylinder, and up to the structure to ground of the printing press. In accordance with one aspect of the present invention, the surface portions projecting radially over the semiconductor covering of the base, define points of electrostatic precipitation, and reduce the surface area available for frictional coupling. The low friction properties of the base semiconductor coating allow free movement of the newly printed sheets in relation to the surface of the transfer cylinder. The sergeant straps carried by the printed sheet material are transferred to the transfer cylinder through the semiconductor covering of the base. The radially projecting, structurally differentiated surface portions are provided with weft threads and warp of spun material in one embodiment, and by knots or balls in an alternative embodiment. According to another aspect of the present invention, the semiconductor base covering, of a low coefficient of friction, for the transfer cylinder, comprises a spun fabric of polyamide glass fiber strands coated with an organic fluoropolymer containing a conductive agent such as carbon black, graphite, or the like. The newly printed sheets are coupled with the strand portions radially probed from the spunbonded coating without marking the newly printed surface or damaging the sheet material itself.

According to another embodiment of the present invention, the cylindrical support surface of the transfer cylinder is covered by a semiconductor fluoropolymer resin layer forming an electrically semiconductive, low friction support surface. In this embodiment, the surface of the semiconductor layer is structurally differentiated by knots or balls. These and other features and advantages of the present invention will become more apparent to those skilled in the art upon reading the following specification with reference to the drawings, which illustrate the exemplary embodiments of the invention. Figure 1 is a schematic side elevational view where multiple transfer cylinders of the present invention are installed in the inter-station positions of a four-color rotary offset printing press. Figure 2 is a perspective view of a delivery cylinder. Figure 3 is a sectional view showing a semiconductor covering of the base, installed on the sheet support surface of the delivery cylinder, taken along line 3-3 of Figure 2. Figure 4 is a view on the upper floor of a semiconductor covering of the base. Figure 5 is a simplified sectional view of the same, which shows the threads of the weft and the warp. Figure 6 is an enlarged sectional view, partially separated, of the delivery cylinder of Figure 2, having a semiconductor covering of the base, in the form of a fluoropolymer resin layer which is impregnated by a conductive agent. Figure 7 is a perspective view showing an alternative embodiment of a semiconductor covering of the base having radially projecting nodes. Figure 8 is a sessional view showing the semiconductor covering of the base of Figure 7 installed on a delivery cylinder. Figure 9 is a perspective view of a portion of the delivery cylinder of Figure 2, the transfer surface of which is covered by a layer of semiconductor balls. Figure 10 is a longitudinal sectional view thereof. Figure 11 is a sessional view showing an alternative mode of a semiconductor covering of the base, which has radially projecting nodes. Figure 12 is a sessional view showing the conductive covering of the base of Figure 11, installed on a delivery cylinder. Figure 13 is an enlarged sectional view, partially separated, of a delivery cylinder having a semiconductor transfer surface that is infused with low friction polymer particles. Figure 14 is an enlarged, partially separated, sectional view of a delivery cylinder having a semiconductor transfer surface that is infused with low friction polymer particles. Figure 15 is a highly amplified pictorial representation of a microscopic section taken through a semicondustoidal surface region of the delivery cylinder of Figure 14. As used herein, the term "processed" refers to different printing methods that they can be applied to either side or both sides of a substrate, including the application of aqueous inks, protective coatings, and decorative coatings. The term "substrate" refers to the sheet material or the fabric material. Also, as used herein, "fluoropolymer" means and refers to fluorocarbon polymers, for example, polytetrafluoroethylene, chlorotrifluoroethylene polymers, fluorinated ethylene-propylene polymers, polyvinylidene fluoride, hexafluoropropylene, and other elastomeric higher polymers containing fluorene, also known and referred to as fluoroelastomers. The term "semicondustor" refers to a sonder material whose surface resistivity at room temperature (70 ° F, 20 ° C) is on the scale of 10 ~ 2 ohms-centimeter to 109 ohms-centimeter which is between the resistivity of the metals and insulators. The term "support cylinder", as used herein, refers to transferensia cylinders, delivery cylinders, support rollers, guide wheels, transferensia drums, and the like. For purposes of example, the present invention is described with reference to a sheet material. However, it will be understood that the principles of the present invention are equally applicable to continuous woven substrates. The improved method and apparatus for handling a processed sonicity substrate is the present invention, it can be used in combination with a high-velocity printing press equipment of the type used, for example, in offset printing. This equipment may include one or more transfer cylinders 10 for handling a processed substrate, such as a freshly printed sheet, between the printing units, and upon delivery of the printed sheet to a delivery stacker. The particular location of the improved support cylinder 10 of the present invention in a transfer position between stations (TI, T3) or in a delivery position (T4) in a rotary offset printing press typically 12, is believed to be easily understood by experts in this field. In any case, reference may be made to my earlier United States patents Nos. 3,791,644 and 4,402,267, which describe details are related to the aligning and working of a sheet support shank in a typical multi-unit printing press. The present invention, of course, can be used with conventional printing presses having any number of printing units or processing stations. Referring to Figure 1, the press 12 includes a press frame 14 coupled on its inlet end to a sheet feeder 16 from which the sheets, designated herein as S, are fed individually and serially to the press. At its delivery end, the press 12 engages a sheet stacker 18, where the printed sheets are collected and stacked. Located between the sheet feeder 16 and the sheet stacker 18, there are four substantially identical sheet printing units 20A, 20B, 20C, and 20D, which are capable of printing different color inks on the sheets as they are transferred to through the press. As illustrated in Figure 1, each printing unit is a conventional design, and includes a plate cylinder 22, a mantle cylinder 24, and a printing cylinder 26. The newly printed sheets S from the printing cylinder are transferred. to the next printing unit by a transfer cylinder 10. The initial printing unit 20A is equipped with an in-sheet feed roller 28, which feeds the individual sheets, one at a time, from the sheet feeder 16 to the initial printing cylinder 26. The newly printed sheets S are transferred to the sheet stacker 18 by a delivery conveyor system, generally designated at 30. The delivery conveyor 30 is of a conventional design, and includes a pair of carrier chains. endless conveyor 32 carrying transversely disposed fastening bars, each having fastening elements for securing the front edge of a freshly printed sheet sa S, as it exits the printing cylinder 26 in the delivery position T4. When the front edge of the printed sheet S is held by the fasteners, the delivery chains 32 pull the clamping bars and the sheet S away from the printing cylinder 26, and transport the newly printed sheet S towards the sheet delivery stacker 18. An intermediate transfer cylinder 11 receives the printed sheets on one side from the transfer cylinder 10 of the previous printing unit. Each intermediate transfer cylinder 11, which is of a conventional design, typically has a diameter that is double of the transfer cylinder 10, and is located between two transfer cylinders 10, in the transfer positions between stations TI, T2, and T3 , respectively. The printing cylinders 26, the intermediate transfer cylinders 11, the transfer cylinders 10, as well as the inward feed roller 28, are each provided with sheet fasteners which hold the front edge of the sheet for pulling the sheet around the cylinder in the direction indicated by the associated arrows. The transfer support cylinder 10, in the delivery position T4, is not equipped with fasteners, and instead includes a large longitudinal opening A which provides tolerance for the passage of the fastener bars of the chain driven delivery conveyor. . The function and operation of the transfer cylinders and associated fasteners of the printing units is believed to be well known to those who are familiar with multi-color sheet feeding presses, and need not be described further, except to note that the printing cylinder 26 functions to compress the sheets against the mantle cylinders 24, which apply ink to the sheets, and the transfer cylinders 10 guide the sheets away from the printing cylinders with the newly printed side of each sheet making contact with the supporting surface of the transfer cylinder 10. Since each transfer cylinder 10 supports the printed sheet with the freshly printed, wet side facing the support surface of the transfer cylinder, the transfer cylinder 10 is provided with an electrically semi-oversize cylinder base covering, of low frission base, 56, as described below. Referring now to Figure 1, Figure 2, and Figure 3, an improved transfer support cylinder 10, constructed to be used in the delivery position (T4), is characterized by a portion of cylindrical flange 34 that is it can be mounted on the frame of the press 14 by an arrow 36. The outer cylindrical surface 38 of the cylindrical rim portion 34, has an opening A that extends along the length of the transfer delivery cylinder between the front edges and rear 38A, 38B, respectively. The transfer delivery cylinder 10 includes the longitudinally spaced hub portions 40, 42, 44, which are formed integrally with the cylindrical flange portion 34. Each hub portion is connected to the cylinder 34 by the tissues 46, 48, and 50, and support the transfer delivery cylinder 10 for rotating on the arrow 36 on a printing press in a manner similar to the mounting configuration described in United States Patent Number 3,791,644. As shown in Figure 2, the transfer delivery cylinder 10 includes opposed elongated integral flange members 52, 54, which extend radially inwardly from the surface of the cylinder 34. The flange portions 52 and 54 include elongate planar surfaces. to ensure a semiconductive base coating, of a low coefficient of friction 56. Referring now to Figure 2 and Figure 3 of the drawings, the improved construction of the transfer delivery cylinder 10 of the present invention is illustrated in detail, which includes the semicondustor base covering 56 to provide a support contact for the printed side of a sheet S while guiding the printed sheet to the next printing unit or to the press delivery stacker. Although the ink-repellent, flexible jacket coating described in my US Pat. No. 4,402,267 provided improvements in the transfer of a freshly printed sheet material, we have found that a sheet transfer can be obtained virtually without runoff, without use the flexible shirt covering. Instead, a low friction, electrically semiconductive base coat on the support surface 38 of the delivery cylinder, support and guide to successive sheets of printed material without transferring the wet ink from a previous sheet to the subsurface sheets, and without smearing or indentating the surface of the newly printed sheet. According to one aspect of the present invention, a semicondust resin compound, preferably a dielectric resin which is a sondusting agent, has produced a substantial improvement in the transfer of the printed sheet material having wet ink onto a surface thereof. as it passes over, and is supported by, the transfer delivery cylinder 10. The semiconductor base covering 56 suitable for sonification with the present invention, and illustrated in the embodiment of Figure 5, comprises a spun material having strands of weft and warp 56A, 56B, which are covered with a low friction semicondustor compound 58. The semiconductor base covering 56 is attached to the flanges 52 and 54, and is wrapped around the cylinder support surface 38, as shown in Figure 3. The semiconductor base covering 56 is preferably rectangular in shape, as shown in Figure 4 and Figure 5, and is dimensioned to completely cover the external support surface 38 of the cylinder 34.

Preferably, the semiconductor compound 58 is polytetrafluoroethylene (PTFE) resin, for example, as sold under the registered trademarks TEFLON and XYLAN, which is impregnated with a conductive agent such as carbon black or graphite. The base coat material of cylinder 56 comprises weft and warp (fill) strands 56A, 56B of polyamide glass fibers, spun together in a base fiber thickness of approximately 0.007 inches (0.2 millimeters). The spun material is resurfaced with semiconductive PTFE to a finished thickness in the range of 0.009 to 0.011 inches (0.2 millimeters to 0.3 millimeters), a finished weight on the scale of 17 to 20 ounces per square yard (56-63 dynes / square centimeter) ), with a tensile strength of approximately 400 x 250 pounds of weft and warp (filling) per square inch 281 x 103 - 175 x 103 kg / m2). In one embodiment, the polyamide fiber comprises spun glass fiber filaments 56A, 56B, covered by semiconductor PTFE in accordance with the Standard of MIL Mil-W-18746B. The PTFE resin composition 58 contains electrically conductive carbon black, or some other equivalent conductive agent such as graphite or the like, preferably in an amount sufficient to provide a surface resistivity not exceeding about 100,000 ohms-centimeter. Although polyamide fiber coated or coated with polytetrafluoroethylene (PTFE) resin, or a fluorinated ethylene-propylene (FEP) resin with carbon black, impregnated with other natural or synthetic organic resins, including linear polyamides such as those sold, is preferred. under the tradename NYLON, linear polyesters such as polyethylene terephthalate sold under the tradename MYLAR, hydrocarbon or halogenated hydrocarbon resins such as polyethylene, polypropylene, or ethylene-propylene copolymers, and acrylonitrile-butadiene-styrene (ABS) , have a surface of low friction coefficient, and can also be combined with a conductive agent, such as carbon black, graphite, or the like, to make the compound electrically conductive. In the preferred embodiment, the surface resistivity of the conductive base coat 56 is approximately 75,000 ohms-centimeter. Other values of surface resistivity can be used with advantage, for example, in the surface resistivity scale of 50,000 ohms-sentimeter to 100,000 ohms-centimeter. The coefficient of friction and the conductivity of the covering material of the base are influenced by the presence of the conductive agent. Accordingly, the amount of conductive agent included in the fluoropolymer resin for a given surface conductivity or resistivity will necessarily involve a compromise with the coefficient of friction. In general terms, a high conductivity (low surface resistivity) and a low coefficient of friction are desired. The amount of conductive agent contained in the fluoropolymer resin is preferably selected to provide a surface resistivity not to exceed about 75,000 ohms-sense, and a frising consistency not to exceed about 0.110. Referring to Figure 2 and Figure 3, the semiconductor base coat 56 is secured to the transfer delivery cylinder 10 by ratchet fasteners 59, 61. An important aspect of the present invention relates to redg the fr icing coefficient of the supporting surface 38 of the cylinder 34. The improved cylinder base support surface has a coefficient of friction less than the frictional coefficient of the surface of the cylinder 38, as can be provided by the coating of the external surface 38 of the cylinder 34 with a fluoropolymer, but having structurally differentiated surface portions that reduce the surface area available for frictional contact against freshly printed sheets. It has been found that the radially projecting surface portions of the embodiments of FIGS., 7, 8, 9, 10, 11, and 12, provide better low friction sliding surfaces that work substantially better to reduce the assumption of ink deposits on the support surface of the base 38 of the transfer cylinder 10. Making Referring to Figure 6, a semiconductor low-friction, base coating is also provided by a semiconductor coating layer 60 applied directly on the cylinder support surface 38. The re-coating sampler 60 is a composite fluorocarbon coating material which contains a conductive agent. A preferred semiconductor composition for providing layer 60 is a polytetrafluoroethylene (PTFE) resin made under the registered trademark XYLAN by Hitford Corporation, Esther, Pennsylvania, impregnated with carbon black. One satisfactory type of coating is the xylan 1010 composite coating material which can be cured at low oven temperatures, for example, at 250 ° F (121 ° C). The semi-conductive base sap 60, as described, provides a substantially glazed surface having a low coefficient of friction of about 0.110, which is semiconductive (surface resistivity of about 75,000 ohms-centimeter), and also provides free movement of the fresh leaves printed by eliminating the electrostatic drapery. Although the low frick, conductive fluoropolymer layer 60 is particularly convenient, other semiconductor re-renderings may be applied to the surface of the transfer cylinder 38 to produce a comparable, low-friction semiconductor support surface. Both the semiconductor spinning base covering 56 (Figure 3) as the semiconductive base layer 60 (Figure 6) have provided the improvement of reducing run-off and ink markings in the high-speed printing equipment, and have also eliminated the depressions and indentations on the printed surface of the leaves. Referring now to Figure 7 and Figure 8, an alternative embodiment of a cylinder base covering is illustrated. In this embodiment, a base sub-assembly 70 comprises a carrier sheet 72, formed of a mouldable material, such as plastic or the like. In accordance with an important aspect of this alternative embodiment, the carrier sheet 72 is molded or pressed to produce multiple knots or radial projections 74 on the side that is blown with the sheet of the carrier sheet 72. Each knot 74 has a curved surface which can be coupled with the blade 74S, which is offset radially with respect to the curved transfer path of the blade S. Preferably, the knots 74 and the surface of the carrier sheet 72 are covered by a layer 78 of a compound of low-friction semiconductor resin, for example, a fluoropolymer impregnated with a conductive agent such as carbon black or graphite. Polytetrafluoroethylene (PTFE) impregnated with carbon black is preferred for this embodiment, and is applied in a layer directly on the surface of the carrier sheet 72 as described above. The knots 74 have a radial projection with respect to the carrier sheet 72 of approximately 4 thousandths, with a cirsunferensial separation between the knot of approximately 2 thousandths (0.05 millimeters). The carrier sheet 72 is electrically connected to the cylinder 34 through the ratchet fasteners 59, 61. The low friction semiconductor coating 78 is applied directly to the carrier sheet, whereby, the electrical charges delivered by the printed sheet S The carrier sheet 72 is spread through the carrier sheet 72 to the cylinder 74 and to the frame of the ground press 14. The carrier sheet 72 must have a thickness gauge that is sufficient to provide strength and dimensional stability, and yet must be sufficiently flexible to be easily wrapped around the ratchet wheel and the support cylinder 34. Generally speaking, thickness gauges in the scale of approximately 2 thousandths (0.05 millimeters) to approximately 24 thousandths (0.6 millimeters) may be advantageously used, depending on the tolerance of the press and the design of the press. Referring again to Figure 8, an advantage provided by the knot mode is a reduced superfisial sontaste between the newly printed sheets and the base covering of the cylinder 70. Due to the curved contour of the knots 74 and the separation of the knots , there is less surface area available for contaste with freshly printed leaves. In sonsesuensia, the force of the frictional coupling is substantially reduced, thus allowing the free movement of the newly printed sheets in relation to the covering of the base of the transfer cylinder. Referring now to Figure 9 and Figure 10, yet another form of semiconductor base coverage is illustrated. In this embodiment, a low friction semicondustor base covering, 80, comprises a metallic carrier sheet 82, constructed of a malleable metal, such as aluminum, copper, zinc, or the like. Conducer carrier sheet 82 has multiple balls 84 secured to its outer surface, for example, by electric welding joints. The surface of the conductive carrier sheet 82 and the balls 84 are covered by a layer 86 of a fluoropolymer resin containing a semiconductor agent, for example, polytetrafluoroethylene (PTFE) resin containing carbon black, as specified above. The balls 84 can be formed of a metal such as aluminum, copper, zinc, or the like, or other material such as nylon polyamide resin. The balls 84 have a diameter of approximately 6 mils (0.15 millimeters), and the thickness of the low friction semiconductor coating layer 86 is approximately 2 mils (0.05 millimeters). Preferably, the coated beads are formed in a rectilinear pattern, and they are separated substantially from each other by approximately 3 mils (0.076 millimeters). The thickness salibre of the conductive carrier sheet 82 is on the scale of about 2 mils (0.05 millimeters) to about 24 mils (0.6 millimeters), depending on the tolerance and design of the press. The separation and the curvature of the coated balls reduces the amount of surface available for contact with the newly printed sheets. The low friction surface provided by the PTFE resin layer 86, together with the circumferential spacing, and the radially projecting portions of the balls, substantially reduce the area of frictional engagement, thereby reducing the surface contact between the sheets newly printed and covering the base of the underlying cylinder 80. In Figure 11 and Figure 12 there is still another embodiment of a semiconductor base covering, with low friction slip. In this alternative embodiment, a semicondustor base covering 90 comprises a base carrier sheet 92 of a moldable plastic material having integrally formed spherical projections 94 configured in a rentilinear array. The base carrier sheet 92 and spherical projections 94 are covered by a semiconductor layer or coating 96 of a fluoropolymer resin containing a sonder agent, for example, polytetrafluoroethylene (PTFE) resin mixed with carbon black or graphite, as specified. previously. In the embodiment of the molded carrier sheet shown in Figure 11 and Figure 12, the semi-capping or re-covering layer 90 is secured in electric sonosting with the cylinder 34 by a link portion 98. The coated spherical projections 94 are spaced apart some with respect to others by approximately 3 thousandths (0.076 millimeters). The thickness gauge of the base carrier sheet 92 is on the scale of approximately 2 thousandths (0.05 millimeters) up to as much as 24 thousandths (0.6 millimeters) or more, subject to the tolerance of the press. The spherical projections 94 have a radius of approximately 3 mils (0.076 millimeters), and the thickness of the low friction conductive coating layer 96 is approximately 2 mils (0.05 millimeters). The radially projecting portions 94 substantially reduce the surface area available for contact, thereby reducing the frictional engagement between the newly printed sheets and the base 90 covering. The spun pattern of Figure 5, and the knot modes of Figure 7 to Figure 12, reduce the amount of surface available for contact of freshly printed sheets. For example, the overlapped warp and weft strands 56A, 56B of the spun pattern shown in Figure 5A provide a lattice-like structure of radially projecting lattice portions that reduce the surface area available to the user. frictional coupling. The low coefficient of friction support function is also provided by the radially projecting knot patterns of Figures 7 to 12. An additional advantage provided by the above embodiments is that the structurally differentiated and radially projecting surface portions, provided by the spun material and by the knots, they concentrate or focus the electrostatic discharge area between the newly printed sheets and the low friction semiconductor base covering. The raised or projecting surfaces provided by the spun material and by the knots, provide discharge points or electrostatic precipitation points of reduced area, where the intensity of the electric field is increased, thereby increasing the transfer of electrostatic charges from the newly printed sheets to the semicondusting base covering 56, and subsequently through of the cylinder 34 and up to the frame of the ground press 14. Referring now to Figure 13, yet another form of semiconductor base covering is illustrated. In this alternative embodiment, a low-framing semicondustor-based covering, 100, comprises an infusion of organisation-lubricating particles 102, preferably polytetrafluoroethylene (PTFE), which are infused into the support surface 38 of the cylinder 34. The support surface 38 is covered or coated with a thin and porous metallic film 104, the PTFE particles being infused through the porous metal film, and partially up to the cylinder 34, thereby providing a semi-overlying base support surface 38E having a It has a low resistivity, and it has a surface resistivity on the scale of 50,000 ohms-centimeter to approximately 100,000 ohms-centimeter. The infusion of a low friction coefficient organic lubricant material such as PTFE is accomplished by providing a thin metal layer 104 of a porous nickel or cobalt alloy, or the like, with boron or the like, which is deposited electrochemically on the surface of the cylinder 38. The cylinder 34 is immersed in a catalytic nucleation plating bath which is a nickel salt and a borohydride reducing agent, the plating index being adjusted to provide a nickel-boron coating layer 104 at a rate of plating deposit of the order of about 1 to 2 mils / hour (0.05 millimeters (0.076 millimeters per hour).) The nucleation of the plating is terminated after the coating layer 104 has formed a metallurgical bond with the surface of the cylinder 38, but wherein the coating layer 104 still retains voids that provide porosity in the range of about 20 percent to 50 percent cent, and having a radial thickness of approximately 1 thousandth (0.025 millimeters) or less. After rinsing and drying, the thin nickel-boron metal layer 104 is heat treated to improve the integrity of the metal bond and to increase the hardness of the porous thin metal layer 104 from about 58-62 Rockwell "C" to about 70. -72 Rockwell "C". The heat treatment is preferably carried out at a temperature of about 650 ° F (343 ° C). An organic lubricating material of low coefficient of friction, for example PTFE, is then applied to the porous surface 38E, and is further treated with heat to cause the organic lubricant material to flow into the voids of the porous metal alloy layer 104. Preferably, the organic lubricant material is infused during the heat treatment at higher temperatures above the melting point of the organic lubricant (preferably at a temperature in the range from about 500 ° F (308 ° C) to about 600 ° F). (315 ° C) for polytetrafluoroethylene), to cause mixing, flow, and infusion, until the voids of the porous metallic alloy sheet 104 are completely filled, thereby providing a deposit of organic lubricant material. After the infusion of the organic lubricant 102, the surface 38E is polished to remove the excess material, exposing the bare metal alloy surface 38E and the pores that have been filled with the organic lubricant. The result is a hardened surface 38E that has a coefficient of friction lower than that of the surface of the cylinder 38, and is electrically semiconductive. Referring now to Figure 14 and Figure 15, an alternative embodiment of the semiconductor base coat is illustrated. In this modality, the cylinder 34 itself is constructed of a porous metal, for example, cast iron. The cast iron that considers that it is relatively porous comparing with the extruded aluminum, for example. The particles of the organic lubricant 102 are infused directly into the region of the porous surface R underlying the supporting surface 38. The infusion of the lubricant 102 is concentrated in the region of the porous surface R, preferably to a penetration depth of approximately 0.001 inches (0.05 millimeters). Organic lubricant particles 102 preferably comprise polytetrafluoroethylene (PTFE). After cleaning, rinsing, and drying the surface 38 of the cylinder 34, the cylinder is heated in an oven to a pre-bake temperature of about 650 ° F (343 ° C) to drain the oils and other volatiles from the region of the porous surface R. The heating step opens and expands the pores in the surface region of the cylinder. While the cylinder 34 is still hot, an organic lubricant, for example, PTFE particles suspended in a liquid vehicle, is sprayed onto the heated surface 38. After the surface 38 has been completely wetted with the liquid organic lubricant solution, it is placed in an oven and heated to a temperature higher than the melting point of the organic lubricant, preferably at a temperature in the range of about 580 ° F (548 ° C) to about 600 ° F (568 ° C) for the polytetrafluoroethylene, to cause mixing, flow, and infusion into the surface pores of the cylinder 34, until the voids of the surface region R are completely filled with the PTFE particles 102. As a result of this heating, the particles of PTFE melt and coalesce, while the solvent boils and is removed by evaporation. After cooling, the surface pores of the cylinder 34 are completely filled with solidified organic lubricant, substantially as shown in Figure 15. After infusion and solidification of the organic lubricant 102, the surface 38 is polished to remove the excess. material, in such a way that the bare metal surface 38 is exposed, and the solid lubricant material 102 of each pore is flush with the bare metal surface 38. That is, any lubricant material 102 or other debris that bridges the metal surface 38 is removed, and the outer face of the solidified organic lubricant tank 102 is leveled with the exposed metal surface 38. The porous surface region that is filled with solidified organic lubricant provides a semi-sedimentation zone for sonication of electrostatic charges from the newly printed sheets through the driver transfer cylinder and up to the press frame to Earth. The newly processed substrates and the low coefficient of friction semiconductive base coating on the surface of the cylinder are electrostatically neutralized with respect to each other, so that the newly processed substrates can continue to move freely, and do not hang towards the surface of semiconductive base support of the cylinder. Another beneficial result of the neutralizing action is that the underlying base support surface becomes more resistant to ink buildup and embedding. Yet another advantage of the electrostatically neutralized substrate material is that it retains its natural flexibility and movability in the absence of the accumulation of the electrostatic charge. Due to the selected polymeric materials used in the construction of the semiconductive base coat, the transfer support cylinder has a longer life, requires less cleaning, and provides greater operational efficiencies. Since the fluorocarbon polymer superfisie of the semiconductor base coating is both oleophobic and hydrophobic, it resists wetting. It is not necessary to wash the semiconductive base support surface of the cylinder, since the semicondustor coating is repellent to the ink, and resists the assimilation of ink, thus reducing maintenance and labor time, while improving salinity and increasing productivity. Furthermore, the removal of electrostatic charges from freshly printed sheets makes the handling of the sheets easier in the delivery unit. By eliminating electrostatic charges on the newly printed sheet, the printed sheets are more easily accommodated to achieve a uniform stack of sheets. Another advantage is that the offset in the delivery stacker is reduced, because the electrostatically neutralized printed sheets are delivered smoothly and uniformly to the delivery stacker. The electrostatic charges are removed from the newly printed sheets as they are transferred through the press, such that each printed sheet is electrically neutralized as it is delivered to the stacker.

Claims

1. A method for supporting a processed substrate as it is transferred from a processing unit of a printing press, characterized by the steps of: providing a rotating member having a substrate surface thereon; providing a base coat of elastically semiconducting material having a fr icing coefficient that is less than the coefficient of frictof the substrate support surface; securing the base covering to the support surface of the substrate and in electrical contact with the rotating member; and rotating the base coat in contact with a processed substrate, and discharging the electrostatic charges carried on the processed substrate towards the base coat, as the processed substrate is transferred from a processing unit.

2 . The method according to claim 1 in claim 1, wherein the base covering comprises a sheet of spun material having strands that are covered with the semiconductor material, characterized in that the step of securing the semiconductor base covering to the rotating member it is made by wrapping the sheet of spun material around the support surface of the substrate.

3. The method according to claim 1, characterized in that the step of ensuring the covering of the base to the rotating member is performed by applying a sack of semiconductor material directly on the substrate supporting surface.

4. The method according to claim 1, wherein the base covering comprises a sheet of spun material having warp and weft threads, and the warp and weft threads are sub-coated with a coating of the semiconductor material. , characterized in that the step of contacting is performed by engaging the coated warp and weft threads against the processed substrate.

5. The method according to claim 1, wherein the covering of the base comprises a carrier sheet having radially projecting nodes, and the nodes are covered with a coating of semiconductor material, characterized in that the step of contacting is done by contacting the coated knots against the processed substrate. The method according to claim 1, wherein the base covering is a carrier sheet having an array of balls arranged on the surface of the carrier sheet, and the balls are covered with a coating of the material semiconductor, characterized in that the step of contacting is performed by coupling the coated balls against the processed substrate. The method according to claim 1, wherein the printing press includes a ground press frame and a cylinder mounted on the press frame to guide a newly processed substrate, characterized in that the step of transferring an electrostatic charge carried on the processed substrate, is performed by conducting the electrostatic charge towards the frame of the ground press through the transfer cylinder, when the semiconductor base covering couples the processed substrate. The method according to claim 1, wherein the covering of the base comprises a sheet of material having radially projecting port, which are covered with a semiconductor material, characterized by the step of concentrating the discharge electrostatic between the processed substrate and the base covering by coupling the processed substrate against the radially projecting port. The method according to claim 1, wherein the covering of the base comprises a carrier sheet having radially projecting nodes, which are coated with the semiconductor material, cosentified by the step of son-concentrating the electrostatic discharge by coupling the newly processed substrate against the coated knots. 10. The method of compliance with the claim in claim 1, wherein the base coating is a bearing carrier having an arrangement of balls that are probed from the surface of the carrier sheet, and the balls are covered with a semiconductor material, characterized by the step of concentrating the electrostatic discharge by means of the coupling of the processed substrate against the coated balls. 11. The method according to claim 1, wherein the semiconductor base covering has structurally differentiated surface portions defining electrostatic precipitation points, characterized by the step of discharging the electrostatic charges carried on the newly printed substrate through of electrostatic precipitation points. 12. The sonicity method is what is recited in claim 1, wherein the printing press is a rotary offset press having multiple printing units, each printing unit employing one mantle cylinder and one printing cylinder to apply one printed image or a protective coating on one side of a substrate that is transferred, which comprises the following steps carried out in each printing unit in succession: applying printing ink or coating material from the mantle cylinder to a substrate, custom-made that the substrate is transferred through the tightening between the printing cylinder and the mantle cylinder; transfer the newly proce substrate from the printing cylinder; and discharging an electrostatic charge carried on the proce substrate towards the semicondustor base covering, as the substrate is transferred from the printing cylinder. The method according to claim 1, wherein the base covering comprises a sheet of spun material having warp and weft threads defining a lattice structure of portions projecting radially, characterized in that the step of contacting is performed by coupling the freshly proce substrate against the radially projecting lattice portions. 14. A transfer cylinder having a substrate support surface for guiding a freshly proce substrate as it is transferred from one printing unit to another, characterized in that: a base covering of an electrically semiconducting material is disposed on the support surface of the transfer cylinder substrate, the semicondustor material having a friction coefficient which is less than the coefficient of friction of the substrate support surface. 15. A conformance transfer cylinder is what is recited in claim 14, characterized in that the semiconductor material comprises a fluoropolymer resin containing a conductive agent. 1

6. A transfer cylinder according to claim 15, characterized in that the fluoropolymer resin comprises polytetrafluoroethylene (PTFE). 1

7. A transfer cylinder according to claim 15, characterized in that the conductive agent comprises carbon black. 1

8. A transfer cylinder according to claim 15, characterized in that the condensing agent comprises graphite. 19, A transfer silo according to claim 14, characterized in that the semiconductor material comprises spun polyamide strands covered with a fluoropolymer resin containing a conductive agent. 20. A transfer cylinder according to claim 14, characterized in that the semiconductor base covering comprises a dielectric resin which is a sonder agent disposed in a solid layer on the substrate support surface of the transfer cylinder. 21. A transfer cylinder in accordance with what is recited in claim 14, characterized in that the covering of the base includes a sheet of spun material having subwoven weft and warp threads, the semi-conductive material. 22. A transfer cylinder according to claim 14, characterized in that the covering of the base comprises a carrier sheet having radially projecting nodes, and the semiconductor material forms a coating layer on the nodes. 23. A transfer silo according to claim 14, characterized in that the covering of the base comprises a mechanical carrier sheet and an array of balls arranged on the surface of the carrier sheet, the semiconductor material forming a coating layer. on the balls. 24. A transfer cylinder according to claim 14, characterized in that the semiconductor material comprises a resin selected from the group consisting of linear polyamides; linear polyesters including polyethylene; terephthalated hydrocarbon or halogenated hydrocarbon resins, including polyethylene, polypropylene, and ethylene-propylene copolymers; and acrylonitrile-butadiene-styrene and polytetrafluoroethylene (PTFE). 25. A transfer cylinder according to claim 14, characterized in that the semicondustor material comprises a fluorinated ethylene-propylene resin (FEP) which is a sondustor agent. 26. A transfer silo according to claim 14, characterized in that the covering of the base of the semiconductor material comprises a porous metal sheet disposed on the support surface of the substrate, and the porous metal layer contains an infusion. of an organic lubricant. 27. A transfer cylinder according to claim 26, characterized in that the porous layer comprises alloyed boron with a metal selected from the group consisting of nickel and sobalt. 28. A transfer cylinder according to claim 26, characterized in that the organic lubricant comprises polytetrafluoroethylene (PTFE). 2

9. A transfer cylinder according to claim 26, characterized in that the covering of the base of the semiconductor material comprises an electrochemical plating deposit of a porous metal alloy on the substrate support surface. 30. A transfer silo according to claim 29, characterized in that: an organic lubricant is disposed inside the porous metal alloy. 31. A transfer cylinder in accordance with what is claimed in claim 30, characterized in that the organic lubricant comprises polytetrafluoroethylene (PTFE). 32. A transfer cylinder according to claim 14, characterized in that the semiconductor material comprises a dielectric resin that contains a sputtering agent. 33. A transfer cylinder according to claim 32, characterized in that the dielectric resin and the amount of conductive agent contained in the dielectric resin are selected to provide the base coverage with a surface resistivity not exceeding approximately 75,000 ohms-centimeter, and a coefficient of friction that does not exceed approximately 0.1

10. 34. A transfer cylinder according to claim 32, characterized in that the dielectric resin comprises a fluoropolymer selected from the group consisting of linear polyamides, linear polyesters including polyethylene terephthalate, hydrocarbon or halogenated hydrocarbon resins including polyethylene, polypropylene, and ethylene-propylene, acrylonitrile-butadiene-styrene copolymers, fluorinated ethylene-propylene polymers, and polytetrafluoroethylene.