Coating apparatus for sheet-fed, offset rotary printing presses

A coating apparatus for use in a sheet-fed, offset rotary printing press to selectively apply a protective and/or decorative coating to the wet ink surface of freshly printed sheets and including a coating unit having a pick-up roller for supplying aqueous coating material from a reservoir to the surface of a delivery cylinder mounted on a press delivery drive shaft, the delivery cylinder performing the dual function of a coating applicator roller and a delivery cylinder during coating operations.

BACKGROUND OF THE INVENTION 
This invention relates to sheet-fed, offset rotary printing presses, and 
more particularly, to a new and improved apparatus for the in-line 
application of protective and decorative coatings to the printed surface 
of freshly printed sheets. 
Conventional sheet-fed, offset rotary printing presses typically include 
one or more printing stations through which individual sheets are fed and 
printed with wet ink. After final printing, the sheets are fed by a 
delivery conveyor system to the delivery end of the press where the 
freshly printed sheets are collected and stacked. In a typical sheet-fed, 
offset rotary printing press such as the Heidelberg Speedmaster line of 
presses, the delivery conveyor system includes a pair of endless gripper 
chains carrying laterally spaced gripper bars and grippers which are used 
to grip and pull freshly printed sheets from the impression cylinder and 
convey the sheets toward the sheet delivery stacker. The gripper chains 
are driven in precisely timed relation to the impression cylinder by 
gripper chain sprocket wheels laterally spaced between a delivery drive 
shaft mounted on opposite sides of the press frame, the delivery drive 
shaft being mechanically coupled by gears for synchronous rotation with 
the impression cylinder. 
Since the inks used with offset type printing presses typically remain wet 
and tacky for some time after printing, special precautions must be taken 
to insure that the wet inked surface of the freshly printed sheets are not 
marked or smeared as the sheets are transferred from one printing station 
to another, and through the delivery system to the sheet delivery stacker. 
One system for insuring that the freshly printed sheets are not marked or 
smeared during transfer is the transfer or delivery cylinder system 
marketed by Printing Research, Inc., of Dallas, Texas under its registered 
trademark "SUPER BLUE" That system, which is made and sold under license, 
is made in accordance with and operates as described in U.S. Pat. No. 
4,402,267, issued Sep. 6, 1983 to Howard W. DeMoore, the disclosure of 
which is incorporated herein by this reference. In that system, marking 
and marring of freshly printed sheets is prevented by employing transfer 
or delivery cylinders provided with a coating of friction reducing 
material such as PTFE (Teflon) over which are loosely mounted fabric 
covers, referred to in the trade as "nets", and which support the wet ink 
side of the freshly printed sheets as they are pulled from the impression 
cylinder. Typically, in a multi-color press employing the "SUPER BLUE" 
cylinder system, each transfer cylinder for conveying the freshly printed 
sheets from one printing station to the next is supplied with a "SUPER 
BLUE" transfer cylinder system, and the delivery cylinder for conveying 
the sheets from the last printing station to the sheet delivery stacker is 
supplied with a "SUPER BLUE" delivery cylinder system. As used 
hereinafter, the term "net type cylinder" is intended to refer to 
cylinders having fabric nets disposed over the support surface, such as of 
the general type disclosed in the aforementioned DeMoore U.S. Pat. No. 
4,402,267 and exemplified by the "SUPER BLUE" cylinder system. 
Another system which can be used to prevent marking and smearing of the 
freshly printed sheets is that disclosed in U.S. application Ser. No. 
07/630,308 filed Dec. 18, 1990 entitled Vacuum Transfer Apparatus for 
Sheet-Fed Printing Presses now U.S. Pat. No. 5,127,329. That application, 
the disclosure of which is also incorporated herein by reference, 
discloses an apparatus which can be employed to draw the unprinted side of 
a freshly printed sheet into engagement with rollers which support the 
sheet on the unprinted side during transfer or delivery of the sheet from 
the impression cylinder after printing so that the wet ink on the freshly 
printed sheet does not come in contact with other apparatus in the press. 
The vacuum transfer apparatus disclosed in that application can be used as 
an alternative to the net type cylinder system disclosed in the 
aforementioned DeMoore patent, or when used in a perfecting press, as a 
supplement to that system, the vacuum transfer apparatus being primarily 
intended for use when only one-sided sheet printing is being performed by 
the press, and the net type cylinder system being used when the press is 
operating in the perfector mode with two-sided sheet printing. 
In some printing applications, it is desirable that the press be capable of 
applying a protective and/or decorative coating over all or a portion of 
the surface of the printed sheets. Such coatings typically are formed of a 
UV-curable or water-soluble resin applied as a liquid solution or emulsion 
by an applicator roller over the freshly printed sheets to protect the ink 
and improve the appearance of the sheets. Use of such coatings is 
particularly desirable when decorative or protective finishes are required 
such as in the production of posters, record jackets, brochures, 
magazines, folding cartons and the like. In cases where a coating is to be 
applied, the coating operation is carried out after the final ink printing 
has been performed, most desirably by an in-line coating application, 
rather than as a separate step after the printed sheets have been 
delivered to the sheet delivery stacker. 
Various suggestions have been made for applying the coating as an in-line 
press operation by using the final printing station of the press as the 
coating application station. For example, in U.S. Pat. Nos. 4,270,483, 
4,685,414, and 4,779,557 there are disclosed coating apparatus which can 
be moved into position to allow the blanket cylinder of the last printing 
station of a press to be used to apply a coating material to the sheets. 
In U.S. Pat. No. 4,796,556 there is disclosed a coating apparatus which 
can be selectively moved between the blanket cylinder or the plate 
cylinder of the last printing station of the press so that that station 
can be used as a coating station for the press. However, when coating 
apparatus of these types are used, the last printing station can not be 
used to apply ink to the sheets, but rather can only be used for the 
coating operation. Thus, with these types of in-line press coating 
apparatus, the press loses the capability of printing its full range of 
colors since the last printing station is converted to a coating station. 
Suggestions for overcoming the problem of the loss of a printing station 
when coating is desired have also been made, such as that set forth in 
U.S. Pat. Nos. 4,934,305 which discloses a coating apparatus having a 
separate timed applicator roller positioned to apply the coating material 
to the printed sheet while the sheet is on the last impression cylinder of 
the press. This is said to allow the last printing station to be operated 
simultaneously as both an ink application station and a coating station so 
that no loss of press printing unit capability results. Another approach 
to providing a coating station without loosing the printing capabilities 
of the last printing station is to provide a totally separate coating unit 
down stream of the last printing station so that the coating is applied to 
the sheets after final printing and before the sheets have reached the 
sheet delivery stacker. Such an approach is suggested in U.S. Pat. Nos. 
4,399,767 and 4,706,601. While each of these suggestions provide coating 
stations which allow the final printing station to continue to be used for 
printing, they each suffer from the disadvantages of requiring the 
provision of separately driven coating applicator rollers and apparatus 
which must be precisely timed in relation to the movement of the sheet to 
be coated so as to insure precise registration between application of the 
coating material and the printed sheet. The provision of separate timed 
applicator rollers require that the presses be modified to provide 
sufficient space within the presses to accommodate the added coating 
apparatus or to increase the length of the presses, and require additional 
and complex drive connections with the press drive system to achieve the 
required precise speed correlation between the sheets and the applicator 
rollers. Such modifications can be both expensive and cumbersome to 
install and maintain. 
Thus, there exists a need for a new and improved in-line apparatus for use 
in a sheet-fed, offset rotary printing press to selectively apply a 
protective and/or decorative coating to the printed surface of freshly 
printed sheets which allows the final press printing station to continue 
to be used as a printing station, yet which does not require any 
substantial press modification or the addition of a separate timed 
applicator roller. As will be explained in more detail hereinafter, the 
present invention solves this need in an novel and unobvious manner. 
SUMMARY OF THE INVENTION 
The present invention provides a new and improved in-line apparatus for 
selectively applying a protective and/or decorative coating to the surface 
of freshly printed sheets in a sheet-fed, offset rotary printing press 
which is highly reliable and effective in use, yet which does not require 
any expensive or substantial press modification or result in any 
impairment of normal press operating capability. The present invention 
enables the press to be used to selectively apply the coating material to 
the freshly printed sheets as the sheets are conveyed from the impression 
cylinder of the last printing station of the press toward the sheet 
delivery stacker by utilizing a delivery cylinder mounted to the existing 
press delivery drive shaft to perform the dual function of a coating 
material applicator roller and a sheet delivery cylinder so that no 
modification of the press is required to enable the press to be used for 
either coating or noncoating operation, and without impairment of any 
normal press operations. 
More specifically, the present invention is intended for use in a 
sheet-fed, offset rotary printing press of the type having at least one 
printing station which includes a blanket cylinder and an impression 
cylinder disposed for printing ink onto sheets passing therebetween, and a 
delivery conveyor system for pulling freshly printed sheets off the 
impression cylinder and transporting the sheets toward the press sheet 
delivery stacker. For use of the present invention, the press must include 
a delivery drive shaft disposed adjacent to and extending parallel with 
the impression cylinder, and which is driven in timed synchronous relation 
with the impression cylinder. 
In accordance with the invention, a delivery cylinder is mounted to the 
delivery drive shaft and provided with a coating blanket disposed over the 
peripheral outer surface of the cylinder, and adapted to engage and 
support the wet ink side of a freshly printed sheet. A coating apparatus 
including a supply of liquid coating material and a pick-up roller 
disposed to receive coating material from the supply, is mounted to the 
press and operable to permit the pick-up roller to be moved into 
engagement with the delivery cylinder so that coating material on the 
pick-up roller is transferred to the coating blanket of the delivery 
cylinder and then to the freshly printed sheet. 
Preferably, the coating apparatus is mounted to the press downstream of the 
delivery drive shaft, and includes means to selectively move the pick-up 
roller into and out of engagement with the delivery cylinder. When the 
pick-up roller is not in the operable position in engagement with the 
delivery cylinder, the delivery cylinder can be used for conventional 
noncoating sheet delivery by removing the coating blanket and, preferably, 
replacing the coating blanket with a fabric net such as of the net type 
cylinder system previously described. To convert to a coating operation, 
the coating blanket is attached to the delivery cylinder and, depending 
upon the thickness of the sheets to be printed, packed with suitable 
packing sheets to increase the effective diameter of the cylinder so that 
pressure is applied to the freshly printed sheets against the impression 
cylinder by the coating blanket covered delivery cylinder. The pick-up 
roller is then moved to the operative position engaged with the delivery 
cylinder so that as freshly printed sheets are pulled by the delivery 
conveyor from the impression cylinder around the delivery cylinder, 
coating material applied to the delivery cylinder by the pick-up roller is 
transferred to the freshly printed sheets in the nip between the delivery 
cylinder and the impression cylinder. 
Since the delivery cylinder is driven by the delivery drive shaft in 
precise timed relation with the impression cylinder, exact registration 
between the application of coating material and the printed sheet is 
assured. Further, since the coating of the freshly printed sheets is 
carried out through use of a delivery cylinder mounted to the existing 
press delivery drive shaft, no substantial press modifications are 
required, and the press can be quickly and easily converted between 
coating and noncoating operation with no loss of printing capability of 
the final printing station. 
Many other features and advantages of the present invention will become 
more apparent from the following detailed description take in conjunction 
with the accompanying drawings which disclose, by way of example, the 
principles of the invention.

DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENT 
As shown in the exemplary drawings, the present invention is embodied in a 
new and improved in-line apparatus, herein generally designated 10, for 
selective use in applying a protective and/or decorative coating to the 
freshly printed surface of sheets printed in a sheet-fed, offset rotary 
printing press, herein generally designated 12. In this instance, as shown 
in FIG. 1, the coating apparatus 10 is illustrated as installed in a four 
color printing press 12, such as that manufactured by Heidelberger 
Druckmaschinen AG of the Federal Republic of Germany under its designation 
"Heidelberg Speedmaster 102V (40")," and which includes a press frame 14 
coupled at one end, herein the right end, with a sheet feeder 16 from 
which sheets, herein designated 18, are individually and sequentially fed 
into the press, and at the opposite end, with a sheet delivery stacker 20 
in which the finally printed sheets are collected and stacked. Interposed 
between the sheet feeder 16 and the sheet delivery stacker 20 are four 
substantially identical sheet printing stations 22, 24, 26 and 28 which 
can print different color inks onto the sheets as they are moved through 
the press 10. 
As illustrated, each of the printing stations 22, 24, 26 and 28 is 
substantially identical and of conventional design, herein including a 
sheet feed cylinder 30, a plate cylinder 32, a blanket cylinder 34 and an 
impression cylinder 36, with each of the first three printing stations 22, 
24, and 26 having a transfer cylinder 38 disposed to withdraw the freshly 
printed sheets from the adjacent impression cylinder and transfer the 
freshly printed sheets to the next printing station via a transfer drum 
40. The final printing station 28 herein is shown as equipped with a 
delivery cylinder 42 which functions to support the printed sheet 18 as it 
is moved from the final impression cylinder 36 by a delivery conveyor 
system, generally designated 44, to the sheet delivery stacker 20. 
The delivery conveyor system 44 herein is of conventional design and 
includes a pair of endless delivery gripper chains 46, only one of which 
is shown in the drawings, carrying at regular spaced locations along the 
chains, laterally disposed gripper bars 48 having gripper elements 50 used 
to grip the leading edge of a sheet 18 after it leaves the nip between the 
delivery cylinder 42 and impression cylinder 36 of the last printing 
station 28. As the leading edge of the sheet 18 is gripped by the grippers 
50, the delivery chains 46 pull the sheet away from the impression 
cylinder 36 and convey the freshly printed sheet to the sheet delivery 
stacker 20 where the grippers release the finally printed sheet. The 
endless delivery chains 46 are driven in synchronous timed relation to the 
impression cylinder 36 by sprocket wheels 52 fixed adjacent the lateral 
ends of a delivery drive shaft 54 which has a mechanically geared coupling 
(not shown) through the press drive system to the impression cylinder. The 
delivery drive shaft 54 extends laterally between the sides of the press 
frame 14 adjacent the impression cylinder 36 of the last printing station 
28, and is disposed to be parallel with the axis of the impression 
cylinder. In this instance, the delivery cylinder 42, which is constructed 
to allow adjustments in diameter by suitable means, is fixedly mounted to 
the delivery drive shaft 54 so that the delivery cylinder is also rotated 
in precise timed relation to the impression cylinder. 
Preferably, each of the transfer cylinders 38 is equipped with an 
anti-marking system such as the aforementioned net type transfer cylinder 
system or the press 12 can be supplied in the transfer positions with 
vacuum transfer systems of the type disclosed in the above-identified 
copending U.S. application Ser. No. 07/630,308 filed Dec. 18, 1990, 
although as will become more apparent hereinafter, the use of such 
transfer systems is not required for the present invention and other types 
of transfer systems can be used. For reasons that will become more 
apparent hereinafter, for most effective use of the present invention, 
however, the delivery cylinder 42 should be of the type which employs the 
"SUPER BLUE" delivery cylinder system, or, as an alternative, should 
employ in the delivery position, a vacuum transfer system such as 
disclosed in the above-identified copending U.S. application Ser. No. 
07/630,308. 
In this respect, it is important to note that when the freshly printed 
sheets 18 are conveyed away from the impression cylinder 36 of the final 
printing station 28 by the gripper 50 carried by the delivery chains 46, 
the wet inked surfaces of the sheets face the delivery drive shaft 54 and 
the sheets must be supported such that the ink is not marked or smeared as 
the sheets are transferred. Typically, such support is provided by 
skeleton wheels or cylinders mounted to the press delivery drive shaft 54, 
or as is now more commonly used, net type delivery cylinders such as of 
the "SUPER BLUE" delivery cylinder system type disclosed in the 
aforementioned DeMoore patent. More recently, vacuum transfer apparatus of 
the type disclosed in the aforementioned copending U.S. application Ser. 
No. 07/630,308 have been used in place of delivery cylinders or skeleton 
wheels to pull the unprinted side of the sheet away from the delivery 
drive shaft 54 so that the wet ink surface of the sheets do not come into 
contact with any press apparatus. It has been found, however, that when a 
protective or decorative coating material is applied to the wet ink 
surface of the sheets, the coating protects the wet ink against marking 
and smearing such that the coating applicator roller itself can be used to 
support the wet inked surface of the sheets without fear of damage to the 
freshly printed surface. 
In accordance with the present invention, the in-line coating apparatus 10 
for selectively applying the protective or decorative coating to the 
sheets 18 enables the press 12 to be operated in the normal manner without 
the loss of the final printing station 28, and without requiring any 
substantial press modifications by employing the existing press delivery 
drive shaft 54 as the mounting location for the coating applicator roller. 
In presses 12 utilizing a net type delivery cylinder system, that system 
can be quickly and easily converted to perform the dual function of being 
a coating applicator roller and a delivery cylinder. In presses having 
other types of delivery systems such as skeleton wheels mounted on the 
delivery drive shaft 54 or a vacuum transfer apparatus as disclosed in the 
aforementioned copending U.S. application Ser. No. 07/630,308, conversion 
to a coating operation can be quickly and easily achieved by mounting on 
the press delivery drive shaft in place of the skeleton wheels or in 
addition to the vacuum transfer apparatus, a suitable support cylinder 
capable of performing the combined function of a coating applicator roller 
and a delivery cylinder 42. Typically, such a support cylinder will have a 
diameter which provides no more than about a 0.090 inch clearance between 
the cylinder support surface and the adjacent impression cylinder 36. By 
utilizing the delivery cylinder 42 mounted on the delivery drive shaft 54 
to also act as a coating applicator roller, the present invention insures 
that the coating will be applied to the printed sheet 18 in precise timed 
registration, and will permit the press to be operated with its full range 
of printing stations, yet allow fast, simple and convenient change-over 
from coating to noncoating operations, and vice versa, with a minimum of 
press down time. 
Toward these ends, the coating apparatus 10 of the present invention 
includes a relatively simple, positive acting and economical coating unit, 
generally designated 60, mounted to the press frame 14 down stream of the 
delivery drive shaft 54 and positioned to selectively supply coating 
material to the support surface of a delivery cylinder 42 mounted on the 
delivery drive shaft. As best can be seen in FIGS. 2, 4 and 6, the coating 
unit 60 herein comprises a pair of side frames 62, only one of which is 
shown, it being understood that the other side frame is substantially the 
same as that of the side frame illustrated, attached to each side of the 
press frame 14. Pivotally mounted to one end of each of the side frames 62 
is a support bracket 64 carrying one end of a coating material reservoir 
66 and cooperating coating material pick-up roller 68 each disposed to 
extend laterally across the press 12 parallel with the delivery drive 
shaft 54. The coating unit 60 is mounted between the upper and lower runs 
of the delivery chains 46 down stream of the delivery drive shaft 54, and 
positioned so that the outer peripheral surface 70 of the pick-up roller 
68 can be frictionally engaged with the support surface of a delivery 
cylinder 42 mounted on the delivery drive shaft. 
As best seen in FIGS. 2 through 4, the support bracket 64 is pivotally 
attached to the end of the side frame 62 by a shaft 72 disposed at the 
lower end portion of the bracket, and can be pivoted about the shaft by an 
extensible cylinder 74, herein shown as a hydraulic cylinder, one end 76 
of which is secured such as by welding to the side frame, and the opposite 
end 78 of which is coupled through a pivot shaft 79 to the upper end 
portion of the bracket. By extending or retracting the cylinder 74, the 
extent of frictional engagement of the pick-up roller 68 with the surface 
of the delivery cylinder 42 can be controlled, and the pick-up roller can 
be completely disengaged from the delivery cylinder. 
The coating pick-up roller 68, which can be of conventional design and 
preferably one such as the Anilox rollers manufactured by A.R.C. 
International of Charlotte, N.C., and sold under the name "PRINTMASTER" 
having an engraved ceramic or chrome outer peripheral surface 70, is 
designed to pick up a predetermined uniform thickness of coating material 
from the reservoir 66, and then uniformly transfer the coating to the 
support surface of the delivery cylinder 42. To effect rotation of the 
pick-up roller 68, a suitable motor 80, herein a hydraulic motor, is 
attached to one of the side frames 62 and coupled to a suitable hydraulic 
fluid source (not shown) through fittings 81. Attached to the output of 
the motor 80 is an output gear which is drivingly coupled through a 
reduction gear 81 and a series of idler gears 82 each mounted on stub 
axles 84, to a drive gear 86 attached to the end of a shaft 88 on which 
the pick-up roller 68 is concentrically mounted. The shaft 88 of the 
pick-up roller 68 is, in turn, journaled at each end to the brackets 64 
through a releasable semi-circular collar 90 (see FIG. 5) attached by 
bolts 92 to the bracket. Herein, the axle of the terminal idler gear, 
designated 82', also serves as the shaft 72 for pivotally mounting the 
support bracket 64 to the side frame 62 so that when the bracket is 
rotated about the shaft, the terminal idler gear remains engaged with the 
drive gear 86 of the pick-up roller 68. 
In this instance, as best as can be seen in FIG. 6, the pick-up roller 68 
has a portion which projects laterally into the reservoir 66 containing 
the supply of coating material, and a pair of upper and lower inclined 
doctor blades 94 and 96 attached to the reservoir engage the roller 
surface to meter the coating material picked up from the reservoir by the 
etched surface 70 of the roller. The reservoir 66 herein is formed by an 
elongated, generally rectangular housing 98 having a generally C-shaped 
cross-section with a laterally extending opening 100 along one side facing 
the pick-up roller 68, and is supplied with coating material from a supply 
tank 102 disposed in a remote location within or near the press 12. 
Preferably, the reservoir 66 is removably attached to the brackets 64, 
herein by bolts 104 having enlarged, knurled heads 106, and which can be 
threaded through slots 108 formed in the brackets to clamp the reservoir 
in place on the brackets. 
To insure that an adequate supply of coating material is always present 
within the reservoir 66 and to prevent coagulation and clogging of the 
doctor blades 94 and 96 by the aqueous coating material, the coating 
material is circulated through the reservoir, herein by two substantially 
identical pumps 110 and 112, one of which pumps coating material from the 
supply tank 102 via a supply line 114 to the bottom of the reservoir, and 
the other of which acts to provide suction to a pair of return lines 116 
coupled adjacent the top of the reservoir for withdrawing unused coating 
material from the reservoir. By circulating the coating material from the 
supply tank 102 at a greater rate than the rate of withdrawal of material 
by the pick-up roller 68, a substantially constant supply of coating 
material will always be present within the reservoir 66. 
In this instance, the general arrangement of the pick-up roller 68, doctor 
blades 94 and 96, and reservoir 66 is substantially like that disclosed in 
U.S. Pat. No. 4,821,672 entitled DOCTOR BLADE ASSEMBLY WITH ROTARY END 
SEALS AND INTERCHANGEABLE HEADS", the disclosure of which can be reviewed 
for details concerning the structure and operation of a pick-up roller and 
reservoir usable with the present invention. 
Once the coating unit 60 has been installed in a press 12, which basically 
only requires that the side frames 62 be attached, such as with bolts, to 
the sides of the press frame 14, and the hydraulic motor 80 be coupled 
with a suitable hydraulic source, the press can be quickly and easily 
converted to the coating mode. In presses 12 already supplied with a net 
type delivery cylinder system, to convert to a coating operation, all that 
is necessary is that the fabric net material (designated 122 in FIG. 3) 
normally used over the support surface of the net type delivery cylinder 
during noncoating press operations, be removed and replaced with a coating 
blanket 124 capable of transferring coating material deposited thereon 
onto the printed sheets. Typically, such a blanket 124 can be formed as a 
rubber covering such as used for the covering surface of the conventional 
blanket cylinders 34 of the press 12. In presses 12 having conventional 
skeleton wheels or a vacuum transfer type apparatus such as that of the 
aforementioned copending U.S. application Ser. No. 07/630,308, a suitable 
delivery cylinder 42 can be fixed to the delivery drive shaft 54 and a 
similar coating blanket 124 applied thereto over the cylinder surface. 
It is important to note that during nonprinting operations, the net type 
delivery cylinder 42 does not engage the surface of the impression 
cylinder 36 during sheet delivery. However, when used as a coating 
applicator roller during coating operations, the effective diameter of the 
delivery cylinder 42 must be increased so that the coating blanket 124 
presses the sheet 18 against the surface of the impression cylinder 36, as 
shown in FIG. 2. To increase the effective diameter of the delivery 
cylinder 42, the thickness of the coating blanket 124 applied over the 
support surface of the delivery cylinder 42 can be selected to correspond 
with the thickness of the sheets 18 to be printed, or suitable packing 
sheets, such as paper sheets (not shown) of the type conventionally used 
in conjunction with press blanket cylinders 34, can be interposed between 
the delivery cylinder and the coating blanket. 
While any suitable means can be used to attached the coating blanket 124 to 
the support surface of the delivery cylinder 42, in this instance, as 
shown in FIGS. 2 and 3, the delivery cylinder is supplied with clamps 126 
attached by bolts 127 to the cylinder adjacent the leading edge 130 to 
secure the leading edge of the coating blanket 124 to the cylinder, and 
adjustable tensioning clamps 128 are provided adjacent the cylinder 
trailing edge 132 for securing the trailing edge of the blanket to the 
cylinder. However, the tensioning claims 128 are pivotally mounted at one 
end by a pin 129 to the cylinder 42, and the blanket tension is adjusted 
through a bolt 131 and nut 133 arrangement. Depending upon the thickness 
of the sheets 18 to be printed and coated by the press 12, one or more 
layers of packing paper or the like may be interposed between the support 
surface of the delivery cylinder 42 and the coating blanket 124 to 
increase the effective diameter of the cylinder. Provision of the 
tensioning clamps 128 for attaching the coating blanket 124 to the leading 
edge 132 of the delivery cylinder 42 allows for such control and 
adjustment. 
Once installed, the coating unit 60 can remain in position even though the 
press 12 is operated in the non-coating mode. In this respect, when the 
coating unit 60 is not in operation, the extensible cylinder 74 can be 
actuated to pivot the support brackets 64 carrying the pick-up roller 68 
and reservoir 66 about the shaft 72 and away from the delivery cylinder 
42, thus rendering the coating unit inoperative. This then also frees the 
pick-up roller 68 and reservoir 66 for fast and easy removal from the 
coating unit 60 for cleaning, service or replacement. To remove the 
pick-up roller 68, the coating material is drained from the reservoir 66, 
and the pressure exerted by the doctor blades 94 and 96 against the roller 
is released, therein through operation of a pressure adjustment screw 120 
attached to the reservoir, and the bolts 92 and collars 90 are removed, 
thereby permitting the pick-up roller to be lifted from the coating unit 
60. To remove the reservoir 66, all that need be done is to release the 
mounting bolts 104 securing the reservoir to the brackets 64. With the 
coating unit 60 moved by the extensible cylinder 74 to the inoperative 
position, the delivery cylinder 42 can be converted for normal delivery 
cylinder operation simply by removing the coating blanket 124 from the 
delivery cylinder 42 and replacing the blanket with a fabric net 122. 
Alternatively, if a vacuum transfer apparatus such as described in the 
aforementioned copending U.S. application Ser. No. 07/630,308 is installed 
in the press 12, that apparatus can be activated to deliver sheets from 
the impression cylinder 36 without effecting any delivery cylinder change 
since the freshly printed side of the sheets will not come into contact 
with the delivery cylinder. 
In a typical noncoating operation of the press 12 with the coating 
apparatus 10 installed, the coating unit 60 will be in the inoperative 
position. In that situation and with a net type delivery cylinder 42 
installed, the delivery cylinder will be covered with the fabric net 122 
so that the delivery cylinder operates in the normal manner with the wet 
ink side of the freshly printed sheets 18 being supported by the net 
covered surface of the delivery cylinder. Should the press 12 include a 
vacuum transfer apparatus such as disclosed in the aforementioned 
copending U.S. application Ser. No. 07/630,308, the delivery cylinder 42 
can remain on the delivery drive shaft 54, with or without a fabric net 
122, depending upon whether or not the press is used for perfector 
printing. 
When it is desired to convert to the coating mode of operation, the press 
12 is stopped just long enough to replace the fabric net 122 on the 
delivery cylinder 42 with the coating blanket 124 packed to the required 
extent necessary for providing the proper pressure to effect coating of 
the sheet thickness to be printed. Thereafter, the pumps 110 and 112 are 
activated and the press 12 re-started. The extensible cylinder 74 can then 
be activated to control the pressure of the pick-up roller 68 against the 
delivery cylinder 42 to obtain the desired application of coating material 
to the freshly printed sheets 18. 
Notably, with the coating apparatus 10 of the present invention, no timing 
adjustments between the delivery cylinder 42 and the impression cylinder 
36 are required to achieve and maintain precise registration between 
application of the coating material and the printed surface of the sheets 
18. Further, the coating unit 60 permits a wide range of coating weights 
to be applied to the printed sheets 18 by quickly and easily changing 
pick-up rollers 68 from those designed to produce a very light coating 
application to those designed to produce a very thick coating application 
can be used. 
From the foregoing, it should be apparent that the coating apparatus 10 of 
the present invention provides a highly reliable, effective and economical 
in-line apparatus for selectively applying coating material to the freshly 
printed sheets 18 in a sheet-fed, offset rotary printing press 12 which 
allows the final printing station to continue to be used as a print 
station, yet which does not require any substantial press modification or 
the addition of a separate timed applicator roller. While a particular 
form of the present invention has been illustrated and described, it 
should be apparent that variations and modifications therein can be made 
without departing from the spirit and scope of the invention.