Multiple color offset rotary printing press with horizontal slide access

A horizontal slide mechanism for removably replacing an inking unit in a rotary offset printing press of the type having a plate cylinder, a blanket cylinder and an impression cylinder having parallel rotational axes. The horizontal slide mechanism includes a first guide track and first slide plate mounted to the printing press and to said inking unit adjacent and parallel to the plate, blanket and impression cylinders for guided horizontal movement parallel to the plate, blanket and impression cylinder of the printing press. A second guide track and second slide plate pair are mounted between the printing press and the inking unit at another location parallel to and spaced apart a predeteremined transverse distance from the first guide track and slide plate pair for guided movement and support of the inking unit. A latching mechanism is provided by which the inking unit is releasably held in a first operating position corresponding to inking engagement.

TECHNICAL FIELD OF THE INVENTION 
The present invention relates to a mechanism, system and method for 
removing and replacing an inking unit on a rotary offset printing press, 
and in particular to a horizontal slide mechanism and system for moving an 
inking unit for access to print rollers of a press and for replaceably 
removing and cleaning the inking unit. 
BACKGROUND OF THE INVENTION 
Rotary offset printing machines have been used for a number of years. The 
basic mechanisms, principles, and steps of operation for modern rotary 
printers include chemically forming an image on a thin metal image plate. 
The thin image plate therearound is attached around the circumference of a 
plate cylinder. Ink and a water solution are applied by inking unit 
rollers and dampening unit rollers to the respective chemically treated 
areas that are to form an image on the image plate as it rotates with the 
plate cylinder. The plate cylinder rolls the image plate against a blanket 
cylinder offsetting a reverse image around the circumference of the 
blanket cylinder. A sheet of print paper or other material to be printed 
is fed into the press and gripped by an impression cylinder. The 
impression cylinder pulls the paper into rolling contact between the 
blanket cylinder and the impression cylinder. Under rolling pressure 
between the two cylinders, the image is imprinted from the blanket 
cylinder onto the paper. The imprinted image is the reverse of that on the 
blanket cylinder so that it is appears as originally formed on the image 
plate. After the paper is imprinted, it is removed from the impression 
cylinder gripper and transferred to a collection tray, if printing is 
finished. If additional colors or images are to be applied, the sheet may 
be transferred to one or more other impression cylinders which grip the 
print paper from a transfer gripper and roll the paper against a 
subsequent blanket cylinder for additional printing. Alternatively, in 
some presses, a large impression cylinder carries the sheet past one or 
more additional blanket cylinders which roll the next color onto the 
sheet. 
In multi-color offset printers, each color is applied as a series of minute 
dots or patterns. It is extremely important to precisely locate or 
register the paper as it is gripped by the impression cylinders, or each 
of them, so that each subsequent matrix of colored dots can be properly 
located and coordinated with respect to other color dots to form the 
desired image. Quality printing requires precise location of the dots 
within thousandths of an inch of each other. An error in alignment of a 
few thousandths of an inch can produce a blurred image or an image with 
improperly mixed and overlapping color dots. 
In the past, multiple color offset rotary printers accomplished this 
precise registration through careful attention to the transfer of the 
paper using precisely manufactured fixed diameter transfer cylinders. 
Usually, the transfer cylinders are large enough to carry two sheets of 
print paper spaced end-to-end around the circumference of the cylinder. 
The rotation of the transfer cylinders had to be carefully timed with 
respect to the rotation of the impression cylinders so that the paper when 
picked up by the transfer cylinders from one of the impression cylinders 
was carried around the transfer cylinder at precisely the correct speed 
and distance so that it was gripped by a subsequent impression cylinder 
precisely in the correct location for registration. The grippers for each 
impression cylinder had to be adjusted until the dots were printed 
precisely at the desired location. 
The use of transfer cylinders has been important because of the extreme 
criticality of precise registration. The cylinders, once formed, have a 
fixed diameter and can be rotated through gears at a fixed speed. 
Repeatable transfers are thus made possible. However, this structure is 
complex and expensive. Further, it introduces associate problems. For 
example, smearing can result because the printed surface of the paper 
being transferred is directed inward on each transfer cylinder. Thus, the 
printed surface of the sheet faces outward toward the blanket cylinder 
when it is gripped by the next impression cylinder. Special coatings, 
special non-stick screens, and even complex systems for air cushioning the 
paper as it is carried around the transfer cylinder have been employed in 
order to minimize this smearing problem. 
The cost of manufacturing multiple color offset printers has been very high 
because of the complexity of multiple transfer gripping mechanisms, large 
precision-built transfer cylinders, and non-smear mechanisms. Further, 
because of the need to properly adjust registration of the paper as it is 
received by each impression cylinder, transferred to each transfer 
cylinder and then received by each subsequent impression cylinder, the 
time and expense to set up any given multiple color offset printing job 
has been substantial. It is not uncommon for an operator to spend a 
considerable amount of time setting up a job and to use over five hundred 
(500) trial printing sheets before proper registration is obtained for all 
of the color impression cylinders. As a result, multiple color offset 
rotary printing has not been economically feasible for most small printing 
jobs requiring less than several thousand copies. 
Traditional rotary offset printing presses employ inking units, including 
sets of rollers, which rollers roll against each other and against the 
printing press plate cylinders. The rollers of the inking unit carry ink 
from an ink source for distributing and applying appropriate quantities of 
a desired colored ink onto the plate cylinder. The plate cylinder holds 
the printing plate which attracts the ink to an image to be printed. The 
ink image is transferred to the blanket cylinder for imprinting it onto 
individual sheets of paper which are held against an impression cylinder. 
There is often limited access area to the plate cylinder, the blanket 
cylinder and impression cylinder of the rotary printing press. It has been 
found to be desirable to allow the inking unit to be movable for purposes 
of allowing easier access to the main cylinders of the printing press. 
Various devices have been developed with varying degrees of success for 
accomplishing the task of allowing access to the main cylinder of printing 
presses. One such device was disclosed in U.S. Pat. No. 4,896,599, issued 
to the present applicant, James J. Keller, titled Swing-Away Colorhead for 
Offset Duplicator. Such a device provided many advantages over fixed 
inking unit systems. For example, that device would allow access to the 
plate cylinder, or to the other internal mechanisms of the press. Still, 
there continues to be a need for a mechanism by which the entire inking 
unit could be conveniently moved for access without removing the inking 
unit entirely, and also a mechanism which would allow the inking unit to 
be removed and replaced with another inking unit (e.g. an inking unit set 
up with a different color). Also, there was a need for providing a 
convenient mechanism and system by which an inking unit having been 
operated with one color of ink could be cleaned for use with another color 
of ink. Further, it has been recognized by Applicant that such a 
convenient mechanism for an inking unit could advantageously include 
sufficient support for convenient removal and replacement of an inking 
unit and a dampener as a connected combination or as an integrally formed 
unit. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a multiple color rotary 
printing press with an inexpensive mechanism for transferring printing 
sheets therethrough with accurate registration alignment at each 
impression cylinder. A transferable gripping bar is provided for gripping 
sheets to be printed. The transferrable gripping bar is provided with a 
registration projection. A corresponding projection receiving pocket is 
formed in each impression cylinder for accurately receiving the 
registration projection and holding the transferrable gripping bar in 
alignment. A conveyor band is attached to the gripper bar for moving the 
gripper bar from one impression cylinder to the next. Thus, a sheet of 
paper is gripped once by the gripper bar and is conveyed by the same 
gripper bar to each impression cylinder in the multiple color rotary 
offset printing press. 
Another feature of the invention is the use of a registration projection 
which is a wheel having a V-shaped peripheral surface and a corresponding 
semi-circular shaped projection receiving pocket having a V-shaped rail 
corresponding to the peripheral shape of the wheel. The pocket rotates 
with each impression cylinder and the conveyor band carries the gripper 
bar to each impression cylinder so that the wheel rolls and slides into 
the pocket in precise registration alignment, both radially and axially 
with respect to the impression cylinder. 
Another feature of the invention employs a registration projection on two 
spaced apart ends of the gripper bar with corresponding registration 
pockets at each axial end of the impression cylinder. A pair of parallel 
conveyor bands are attached at each end of the gripper bar to carry it 
suspended therebetween, as it is conveyed from one impression cylinder to 
the next. The gripper bar is attached to the conveyor band with a flexible 
bracket so that minor misalignment of the conveyor band with respect to 
precise registration is accommodated when the registration projection 
engages into the registration pocket. In this manner, inexpensive conveyor 
bands such as roller chains on sprockets or indexable belts on pulley 
gears can be employed as the conveyor band, even though minor deviations 
in the indexing of the band with respect to the rotation of the impression 
cylinders may result from wear or stretching and the like. 
Another feature is to provide smooth positive engagement and disengagement 
between a registration projection wheel and receiving pockets at each 
impression cylinder. An entry guide is positioned at each impression 
cylinder to positively push the registration wheel into the receiving 
pocket while the paper to be printed becomes firmly engaged in printing 
contact between the impression cylinder and the blanket cylinder. An exit 
guide is also positioned at each impression cylinder to lift the 
registration wheels out of the receiving pockets so that the gripper bar 
moves smoothly away from the impression cylinder with the horizontal 
transfer chain. Parallel guides above and below the gripper bar hold the 
gripper bar in a horizontal orientation against twisting forces applied to 
actuate the gripper fingers. 
Another feature is an actuation arm directly connected to rotate the 
gripper fingers between an open paper insertion position and a closed 
paper gripping position. The arm is actuated upwardly by a cam surface to 
an open position and is biased downward into a closed gripping position. 
Another feature is the straight through transfer of printed sheets of paper 
from the gripper bar to a transfer gripper for removing and stacking 
printed paper. 
Yet another feature is the use of idler sprockets in the return conveyor 
path for holding the gripper bars away from the impression cylinders. This 
reduces wear due to unnecessary engagement between projection wheels and 
receiving pockets during the return cycle. 
It is an object of the present invention to provide a horizontal slide 
mechanism for removably replacing an inking unit in a rotary offset 
printing press of the type having a plate cylinder, a blanket cylinder and 
an impression cylinder having parallel rotational axes. The horizontal 
slide mechanism includes a guide track rigidly mounted to the printing 
press adjacent and parallel to the plate, blanket and impression 
cylinders. The guide track forms a predetermined shape for allowing a 
slide plate to move horizontally along the guide track. The slide plate is 
movably engaged in the guide track. 
In one embodiment, a pivot mount is attached to the slide plate and is 
attached to the inking unit for providing a single pivot axis 
therebetween. The pivot axis of the pivot mount is parallel to the 
rotational axis of the plate cylinder. The pivot axis is spaced apart from 
the plate cylinder at a position for pivoting the inking unit between a 
first and a second pivot position, with the first pivot position 
corresponding to inking engagement with the plate cylinder, and the second 
pivot position corresponding to a spaced apart disengaged position at 
which said inking unit is not in engagement with the plate cylinder. A 
latching mechanism is provided by which the inking unit is releasably held 
and locked in the first pivot position corresponding to inking engagement 
with the plate cylinder. 
In another embodiment, a first slide plate and first guide track are 
attached between an inking unit and a press at a first location and a 
second slide plate and second guide track are another location, parallel 
to the first slide plate and first guide track, spaced a transverse 
distance so that the inking unit is supported against cantilever tilting 
force on the first guide track and slide plate mechanism. 
Preferably, the first guide track includes the first plurality of 
horizontally aligned rollers having a first predetermined profile shape 
and a second plurality of horizontally aligned rollers having a second 
predetermined profile shape. The first and second sets of horizontally 
aligned rollers are positioned parallel to each other, spaced apart a 
predetermined distance. The first slide plate preferably includes a first 
horizontal ridge having a cross-sectional shape corresponding to the 
reverse image of the first predetermined profile shape of the first set of 
rollers for rolling engagement therewith, and also including a second 
horizontal ridge having a predetermined cross-sectional shape 
corresponding to a reverse image of the second predetermined profile 
shape, parallel and spaced apart a predetermined distance from said first 
horizontal ridge, for simultaneous rolling engagement with the second set 
of horizontally aligned rollers. 
Preferably, the second guide track and slide plate comprise a set of 
horizontally aligned rollers having a flat surface profile and a 
horizontal slide plate having a flat surface against which said rollers 
engage the slide plate in supported rolling contact. 
It is a further object of the present invention to provide guide tracks and 
slide plates which overlappingly extend in opposite directions a 
sufficient distance to provide support for the inking unit adjacent to the 
printing press for access to the plate cylinder and other areas of the 
press without complete removal of the inking unit. 
It is a further object of the invention to provide a first guide track 
which comprises concave V-shaped rollers with corresponding convex 
V-shaped profile for the horizontal ridges on the slide plate, so that the 
slide plate and the attached inking unit are accurately maintained 
parallel to the axis of the plate cylinder. 
It is a further object of the invention that a latching mechanism be 
provided which both securely holds the inking unit against horizontal and 
transverse movement and in the first engaged position and which holds the 
inking unit securely against horizontal movement with a locking pin so 
that the inking unit does not inadvertently slide out of registration 
during operation. 
It is a further object of the invention that the drive gear of the printing 
press automatically engages with the power receiving gear of the inking 
unit upon engagement in the first position and automatically disengages 
upon raising the inking form rollers from the plate cylinder and sliding 
the inking unit to the second disengaged position. Preferably, the inking 
unit is provided with a form roller raising mechanism by which the form 
rollers may be separated from the plate cylinder, and an external manual 
rotation knob by which the rotational position of a power takeoff gear of 
the inking unit can be adjusted slightly so that gear meshing with a press 
drive gear is accomplished without binding of either the rollers or the 
gears during movement from the second disengaged position to the first 
engaged position. 
It is further object of the invention to provide a movable inking unit 
receiving tray having horizontal receiving guide tracks or slide plates 
for receiving the slide plates or guide tracks attached to the inking 
unit. The receiving tray is constructed so that the height of the 
receiving guide tracks or slide plates can be adjustably positioned so 
that sliding transfer of the inking unit from the printing press to the 
receiving tray is easily accomplished. 
It is a further object of the invention to provide the receiving tray with 
ink cleaning capabilities by which an appropriate solvent can be directed 
to the ink rollers of the inking unit. Preferably, used solvent liquid can 
be collected and a hood is provided so that solvent vapors can also be 
appropriately vented. 
It is a further object of the invention to provide parallel spaced-apart 
guide track and slide plate pairs between the press and the inking unit so 
that the inking unit is supported for horizontal sliding and is also 
supported against tilting or cantilever caused by the weight of the inking 
unit. 
It is a still further object of the invention to provide parallel guide 
track and slide plate pairs between the press and an interconnected inking 
unit and dampening unit which parallel guide track and slide plate pairs 
are spaced apart a sufficient transverse distance to provide adequate 
support to the inking unit and dampening unit so that non-binding 
horizontal sliding is obtained, and also a moveable receiving tray having 
corresponding spaced-apart parallel guide track and slide plate pairs for 
slidably receiving the interconnected inking unit and dampener unit. 
Further, the receiving tray is preferably provided with cleaning 
capabilities.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows a schematic side view of a multiple color offset rotary 
printing press 10. The press includes a first set 12 of color cylinders 
and rollers, including a first plate cylinder 14, a first blanket cylinder 
16, and a first impression cylinder 18. An inking unit 20, including a 
plurality of inking rollers and a dampening unit 21, including a plurality 
of dampening rollers, are held and configured adjacent to the plate 
cylinder and in contact therewith. Ink and a dampening solution are 
thereby applied to a printing plate carried around plate cylinder 14. The 
image from plate cylinder 14 is applied in reverse to blanket cylinder 16. 
A sheet of paper 22 is fed between blanket cylinder 16 and impression 
cylinder 18 to imprint the image from the blanket cylinder onto the sheet 
22 to be printed. In the embodiment shown in FIG. 1, the sheet 22 is 
conveyed on conveyor band 24 from the first set 12 to the second set 26 of 
color image applying cylinders. A second plate cylinder 28 receives ink 
from a second inking unit 27, and also receives dampening solution from a 
second dampening unit 29. A second color image is transferred to a second 
blanket cylinder 30 which in turn imprints the second color image on the 
sheet as it is rolled between blanket cylinder 30 and second impression 
cylinder 32. The sheet is carried along conveyor band 24 to each 
subsequent set of color cylinders and rollers 34 and last set 36. Each set 
operates substantially similar to the first and second sets to print an 
image or a portion of the image, such as one color formed of a matrix of 
dots or small patterns. After each matrix of dots and patterns are 
imprinted on sheet 22, it is transferred by conveyor band 24 to a skeleton 
cylinder 38 where it is released from the conveyor band 24 and carried by 
a delivery chain 60 to deliver the printed sheet to a collection tray 64. 
Conveyor band 24 is operatively connected attached to a gripper bar 48 so 
that the gripper bar is moved by the conveyor band from the first 
impression cylinder 18 to the second impression cylinder 32 and to 
subsequent impression cylinders 54 and 58. Uniquely, according to one 
embodiment of the present invention, the sheet is continuously held by 
gripper bar 48 so that the sheet is not released and regripped at each 
impression cylinder. Rather, the gripper bar is moved from impression 
cylinder to impression cylinder. The conveyor band is supported with drive 
wheel 40 at impression cylinder 18, drive wheel 52 at impression cylinder 
32, and a drive wheel 53 at each subsequent impression cylinder 54 until 
the last impression cylinder 58 has a corresponding drive wheel 56. The 
conveyor band 24 continues around a drive wheel 59 which is attached to 
the skeleton cylinder 38, so named because there is no impression 
cylinder, but rather only the wheel 59 for returning the continuous 
conveyor band 24. The gripper bar 48 is attached to the conveyor band 24 
so that it moves around skeleton cylinder 38 past the bottom of each 
impression cylinder 56, 54, and 52 and is re-engaged in proper 
registration with impression cylinder 18 for beginning the imprinting 
process again. 
FIG. 2 shows an operator side view of one embodiment of a multiple color 
offset printing press 230. In the particular embodiment shown in FIG. 2, a 
two-color printing press 230 is depicted. There are horizontal slide 
mechanisms 234(a) at the first color printing position and 234(b) at the 
second color printing position. Inking units 238(a) and 238(b) are mounted 
on horizontal slide mechanisms 234(a) and 234(b), respectively. As will be 
shown in greater detail below. 
FIG. 3 shows an enlarged partial perspective view from the operators side 
of a multiple offset press 230 of FIG. 2. One printing station is depicted 
as representative of duplicate slide mechanisms 234 at each printing 
station, depending on the number of print stations or colors of the press. 
A four-color press would have four stations with four inking units 238, 
four slide mechanisms 234, four sets of plate, blanket and impression 
cylinders and four dampening units. Each slide mechanism 234 includes a 
guide track 240 which is parallel and adjacent to the primary printing 
head cylinders (i.e. the plate, blanket and impression cylinders). 
Slidably engaged in the guide track 240 is a slide plate 242. The guide 
track 240 holds the slide plate 242 parallel to the press cylinders and 
permits it to slide horizontally parallel to the surface 244 of the plate 
cylinder 14. For a uniform diameter plate cylinder, the slide plate moves 
parallel to the rotational axis 246 of the plate cylinder. Thus, the 
inventive slide mechanism 234 allows the inking unit to move transverse to 
the direction of motion of the sheets 18 which are being printed. 
In one preferred embodiment, the guide track 240 is formed with a first set 
248 of guide rollers 250 (a-e), all horizontally aligned with each other. 
The guide track 240 also includes a second set 252 of rollers 254(a-e) 
which are also horizontally aligned with each other. The second set of 
rollers 252 is vertically spaced apart a predetermined distance from the 
first set of rollers 248. Each of the first rollers 250 has a 
predetermined profile surface shape for providing both vertical and 
horizontal components of holding force, while allowing horizontal 
transverse movement. Concave V-shaped rollers are used in the preferred 
embodiment. The second rollers 254 also have a predetermined profile 
surface shape which provides support in both vertical and horizontal 
directions, while allowing transverse horizontal movement. The guide track 
is thereby formed between the first set and the second set of parallel 
rollers. The slide plate 242, preferably, has a first ridge 256 which has 
a profile shape corresponding to the reverse image of the profile shape of 
the first rollers 250 for engagement therealong. The slide plate 242 
further, preferably, includes a second parallel ridge 260 which has a 
profile shape 262 which corresponds to the reverse image of the profile 
surface of the second rollers 254. The first and second parallel ridges 
are spaced apart a predetermined distance which corresponds to the spacing 
between the first and second sets of rollers so that the ridges may be 
"slid" between the rollers. The rollers preferably make rolling contact, 
rather than actual sliding contact, along the ridges. It will be 
understood that a guide track could be formed, as with parallel grooves, 
which, with proper lubrication, could permit sliding engagement. However, 
the rolling engagement of the slide plate with the effective guide track 
formed by the rollers is found to be advantageous in its smoothness and 
consistency of operation without requiring significant amounts of 
maintenance. For example, self lubricated sealed ball bearings can be used 
for each of the rollers 254(a-e) and 250(a-e), thereby minimizing 
maintenance while maximizing the rigidity of hold as well as ease of 
movement of the slide plate horizontally, parallel to the plate cylinder 
surface. 
Advantageously, in the embodiment depicted in FIGS. 2, 3 and 4, the inking 
unit 238 is mounted to the slide plate 242 through a pivot mount 264. The 
pivot mount 264 provides a pivot axis 266 which is parallel to the surface 
244 of plate cylinder 14. The inking unit 234, in combination with mount 
264, is constructed to permit the inking unit to pivot between a first 
position in which the inking unit 238 is operationally engaged with the 
surface 244 of plate cylinder 14 to appropriately apply ink thereto. Also, 
inking unit drive gear 268 is engaged with the takeoff gear 270 (see FIG. 
4) when inking unit 238 is pivoted into the first operationally engaged 
position. A second pivot position, as depicted in FIG. 3, disengages the 
inking unit 238 from plate cylinder 14. In this position, the inking unit 
can then be laterally slid on slide unit 234 to a position which is 
transverse to the printing sheet path. In the embodiment shown in FIG. 3, 
inking unit 238 is slid toward the non-operator side of the press, or to 
the back of the press where the operator side of the press is considered 
the front of the press. 
In FIG. 3 there is also depicted, in partial phantom lines, a receiving 
tray 272 having therein a rigid receiving guide track 274. In the 
preferred embodiment, receiving track 274 may be constructed with upper 
and lower sets of guide rollers 276 and 278, respectively, which form a 
track substantially the same as with guide track 240. The receiving track 
is mounted to the receiving tray 272 in a cleaning receptacle 280 which 
may be provided with a movable lid 282, such as a hingeably mounted lid 
282. Also, preferably, the cleaning receptacle may have attached thereto a 
cleaning apparatus 284, for cleaning a received inking unit. The details 
of construction of the receiving tray 272 will be discussed more fully 
below with reference to FIG. 5. 
FIG. 4 depicts an enlarged partial side view showing the back side of one 
embodiment of a multi-color offset press 230 and inking unit 238. The 
inking unit 238 is shown in its first position in an operationally engaged 
relationship with plate cylinder 14 of press 230. The second pivot 
position, in which the inking unit is disengaged, is shown in phantom 
lines. In the first pivot position 286, both the drive gear 268 and the 
power takeoff gear 270 are in mesh with each other at 288. Also, at least 
one of the inking rollers 290 (depicted in hidden line) is engaged with 
the surface 244 of plate cylinder 14. In the second, or disengaged, 
position 292 a gap 294 is produced between the plate cylinder 14 and the 
inking unit 238. In the first operational position, a cam lock mechanism 
296 is provided by which a progressively tighter engagement is achieved 
along cam ramp 298 upon rotation of lock mechanism 296. The cam lock 
surface 298 operates against a rigid pin 300 which is located on the 
inking unit 238. Preferably, duplicate cam locking units 296 are formed on 
both the operator side and the back side of the press, and a locking pin 
302 is formed at least on the operator side by which the cam mechanism 296 
is locked so that the inking unit 238 can be secured into its 
operationally engaged position. In order to disengage the inking unit, the 
lock pin 302 would first need to be disengaged and then the cam mechanism 
296 could be rotated to disengage pin 300. Also, it will be understood by 
those skilled in the art that moving the inking unit from the disengaged 
to the engaged position may sometimes require rotation of the inking unit 
as with a knob 304, to allow gears 268 and 272 to be properly aligned for 
engagement. 
With reference to FIG. 5, the construction of the inking unit receiving and 
cleaning tray 272 will be more fully understood. The inking unit 238, 
which continues to be pivotably mounted on slide plate 242, is received in 
a receiving guide track 274 which is mounted within the cleaning 
receptacle 280. The cleaning receptacle 280, preferably, forms a lower 
portion of the receiving tray 272. An opening 306 is formed which extends 
below the position of the receiving track 274 at one side of the cleaning 
receptacle 280. Sufficient opening clearance is allowed for the receiving 
tray 272 to be positioned immediately adjacent guide track 240, so that 
guide track 240 and receiving track 272 are in alignment. For this 
purpose, wheels 308 may be provided on the receiving tray 272 to allow is 
to be moved to the desired position. Also, height adjustment mechanism 400 
may be provided by which the vertical position is guide track 272 can be 
precisely adjusted to allow easy sliding engagement. Lid 284 can be 
closed, as shown in FIG. 5, to totally enclose the inking unit 238. The 
lid is constructed with side walls 312 and 314 which correspond in shape 
for overlapping engagement with side walls 316 and 318 of receptacle 280. 
A cleaning apparatus, generally designated 284, is advantageously provided 
mounted to the cleaning receptacle 280 so that the receiving and cleaning 
tray 272 is substantially self-contained. There is a source 320 of 
cleaning solvent or cleaning fluid. Preferably, the source is 
self-contained such as a refillable reservoir 320 for holding a cleaning 
fluid and which is mounted, preferably, within receptacle 280. A conduit 
322 communicates the fluid to a pump 324. The pump 324 is, preferably, 
selectably operated with a motor 326 which may be either a low voltage DC 
electrical motor or, alternatively, may be a hydraulic or compressed air 
driven motor 326. Operator controls 327, such as a switch 327, may be 
positioned for easy access by the operator. The cleaning fluid from 
reservoir 320 is thereby pumped through conduits 322 and 328 to a 
directable cleaning nozzle 330. Nozzle 330 may be positioned for spraying 
directly onto the ink rollers of the inking unit 338 or, alternatively, 
may be flexibly mounted so that an operator may direct the spray as 
desired to particular areas to be cleaned. Also, advantageously, the motor 
may include a shaft 332 having a socket coupler 334 which is adapted to 
engage with the inking unit for driving it in rotation while the cleaning 
solvent is sprayed onto the ink rollers. For example, a socket which 
engages with positioning knob 304 may be used to accomplish this purpose. 
A closable access opening 328 might also be formed in lid 282 to permit 
the operator access for directing nozzle 330 or, alternatively, for 
providing a plexiglass view window by which the operation of the cleaning 
unit can be observed. Also, a vent 340 is provided to safely remove any 
evaporation of ink solvent. A drain 342 might also be provided to allow 
convenient removal of used solvent from the bottom of receptacle 280. 
FIG. 6 depicts horizontal slide mechanisms 350, 352, 354 and 356 shown 
attached in an alternative embodiment to a multi-color printing press 360. 
In this embodiment, the printing press 360 is of the type having an 
enlarged central impression cylinder 362 having a plurality of sheet 
holding areas 364, 366, 368 and 370. There are a plurality of printing 
units 372, 374, 376 and 378, each including a plate cylinder and a blanket 
cylinder. Therefore, associated with each set 372, 374, 376 and 378 of 
primary printing cylinders, there is a corresponding inking unit 352, 354, 
356 and 358 attached, according to the present invention. Also, associated 
with each printing area is a dampening unit schematically depicted as 
380,382,384 and 386. The horizontal slide mechanisms 234(c), 234(d), 
234(e) and 234(f) are attached to inking units 352, 354, 356 and 358 with 
a construction corresponding to the construction as described with respect 
to inking unit 238, and corresponding slide mechanism 234, as discussed 
with respect to FIGS. 2, 3, 4 and 5, except that slide mechanisms 234(e) 
and 234(f) are shown in a reverse direction. For some presses, it may be 
possible to mount a slide mechanism 234(e) and 234(f) in the same 
orientation as with the slide mechanisms 234(c) and 234(d). Such a 
construction may be advantageous for purposes of having a consistent ink 
receptacle and cleaning tray construction. This is not necessary for some 
aspects of the invention. In any press configuration where it is more 
convenient to mount the inking units oriented in reverse directions, the 
slide mechanisms can also be advantageously reserved. In those instances, 
as shown in FIG. 6, either separate receiving and cleaning trays may be 
used or, alternatively, receiving and cleaning trays having entry 
thereinto from both directions may be constructed for convenient receiving 
of the slidable inking units from either orientation on the press. 
FIG. 7 shows a schematic partial perspective view of an alternative 
embodiment of a rotary offset printing press 400 which is of the type 
having an impression cylinder 402, at least one blanket cylinder 404, and 
a plate cylinder 406, within press frame 408 which are operatively mounted 
within press frame 408 for rotary offset printing operations. An inking 
unit 410 is advantageously mounted using a horizontal slide mechanism and 
system generally designated as 412 for replaceably removing an inking unit 
410 from the rotary offset printing press 400. Structurally, the inking 
unit generally includes a frame 414, an ink reservoir or supply 416, a 
plurality of ink transfer and smoothing rollers 418 by which ink is 
supplied to one or more form rollers 420 and 421. Typically, the inking 
unit 410 is provided with a mechanism 422 by which the form rollers may be 
moved vertically into and out of ink transfer rolling engagement with 
plate cylinder 406. The form roller lifting mechanism may individually or 
simultaneously lift form rollers 420 and/or 421 out of rolling contact 
with plate cylinder 406. The horizontal slide mechanism 412 comprises a 
first guide track and slide plate pair, including a first guide track 424 
and a corresponding first slide plate 426. In the embodiment shown in FIG. 
7, the first guide track 424 is securely affixed to press frame 408 in a 
horizontal orientation. The first slide plate 426 is affixed to the frame 
414 of the inking unit 410 in a horizontal relationship. The first guide 
track 424 is parallel to the plate cylinder 406 and the first slide plate 
426 is parallel to the plurality of inking rollers 418 and, in particular, 
to the form rollers 420 and 421, so that upon sliding engagement between 
the guide track 424 and the slide plate 426 the form rollers 420 and 421 
are in a parallel, adjacent relationship to the plate cylinder 406. 
In a further preferred embodiment, as depicted in FIG. 7, the horizontal 
slide mechanism further comprises a second guide track and slide plate 
pair, including a second guide track 442 and a corresponding second slide 
plate 444 which are mounted to the press frame 408 and to the inking unit 
410 in a horizontal relationship, again parallel to the plate cylinder 406 
and to the plurality of inking rollers 418 and the form rollers 420 and 
421. The second guide track and slide plate pair is spaced apart from the 
first guide track and slide plate pair to provide support against tilting 
and cantilever bending. 
The embodiment of the first guide track as depicted in FIG. 7 includes an 
upper plurality of rollers 428 and a lower plurality of rollers 430. The 
rollers 428 and 430 preferably have a V-shaped surface profile which 
correspond in shape to an upper V-shaped trough 432 and a lower V-shaped 
trough 434 formed on the slide plate 426. The slide plate can, therefore, 
be slid between and along the upper rollers 428 and the lower rollers 430 
through rolling contact in a horizontal direction while preventing motion 
of the inking unit in a transverse direction (i.e., a direction 
perpendicular to the axial direction of the press cylinders and the inking 
unit roller). The close fit interaction between the profile shapes of the 
rollers 428 and 430 and the profile of the channels 432 and 434 of the 
slide plate 426 also provide support against a bending moment caused by 
the weight of the inking unit. However, to further relieve this bending 
moment and the additional twisting forces imposed upon the profile shape 
surface of the rollers of the guide track and the slide plate ridge 
surfaces, the second guide track 442 and the second slide plate 444 are 
positioned at a transverse offset horizontal distance 450. 
The second guide track 442, as depicted in FIG. 7, comprises a plurality of 
horizontally aligned rollers 446. The second slide plate 444 has a 
horizontal surface which is positioned for corresponding rolling 
engagement with the rollers 446. As the rollers 446 of guide track 442 
provide vertically upward support, they may conveniently be formed with a 
profile shape corresponding to that of the horizontal surface of the slide 
plate 444 which, in the embodiment shown, is flat but could also be a 
round bar to save space (as shown in FIG. 8 below). The horizontal surface 
of the second slide plate 444 may similarly be a flat surface or could 
also be round. In this embodiment, the support against transverse movement 
of the inking unit is primarily provided by the first guide track and 
first slide plate which preferably have V-shaped rollers and V-shaped 
surfaces, as discussed above. Optionally, the second guide track 442 may 
also be provided with additional support rollers 448 and the second slide 
plate is provided with an additional horizontal slide surface to provide 
support, in the event that an upward directed force is applied to the 
inking unit. 
The inking unit is preferably rigidly engaged into its first operating 
position through the use of a taper pin 436 which engages a taper hole 
438. The taper pin may be attached to the inking unit and the taper hole 
may be attached to the press frame, as depicted. Alternatively, a taper 
pin may be attached in a reverse direction to the press frame 408 and the 
taper hole may be formed in frame 414 of the inking unit 410, without 
departing from this aspect of the invention. Further, a taper hole 440 may 
be formed or attached to the opposite end of the press frame 408 for 
receiving a second taper pin (not shown) which extends inward from the 
opposite end of the inking unit frame 414. When the tapered pin or pins 
are fully engaged, a latch 441 may be engaged to prevent horizontal 
disengagement. With these pins engaged, as when the inking unit is in its 
first operating position as opposed to its second disengaged position as 
shown in FIG. 7, the rotational torque caused by the rolling contact 
between the plate cylinder and the inking unit is resisted with the 
rigidity of the taper pins. However, as the inking unit is moved from its 
first operational position to the second disengaged position, as depicted 
in FIG. 7, the taper pins no longer provide support against rotational 
moment and the lower rollers 446 provide such support through rolling 
engagement with the second slide plate 444. In the disengaged situation, 
the press will be disabled and there will be no reverse direction rotation 
so that lower rollers 446 adequately support the inking unit against 
downward motion. This takes tension and strain off of the first guide 
track rollers 428 and 430. 
The embodiment depicted in FIG. 7 is further advantageous for purposes of 
affixing a dampening unit 452 directly to the inking unit 410, as at a 
plurality of fastener locations 454. Rigid connection of the dampening 
unit 452 to the inking unit may be accomplished with threaded bolt 
fasteners 456 or other fasteners, welding or even integral formation of 
the frame 414 of the inking unit and also the frame 458 of the dampening 
unit. 
Advantageously, the embodiment of the sliding mechanism which includes 
first and second guide tracks and first and second slide plates provides 
adequate support for the inking unit and the combined weight of the 
dampening unit attached to the inking unit. With modern hydrophilic 
dampening units, the ability to conveniently remove the inking unit and 
the dampening unit for purposes of cleaning, and particularly removal into 
a receiving tray which has corresponding receiving tracks, greatly 
facilitates the operation and setup of rotary offset printing presses. The 
receiving tray may be provided with cleaning capabilities such as those 
depicted in FIG. 5 above. This is particularly advantageous where a 
multiple color rotary offset printing press is involved which may require 
frequent changes of color at any given position. Each separate color 
application position, including a plate cylinder, blanket cylinder and 
inking and dampening unit, can be provided with a horizontal slide 
mechanism similar to that depicted in FIG. 7. Both the inking mechanisms 
and the interconnected dampening units can be removed simultaneously for 
cleaning and for access to the plate cylinder. The plates can easily be 
removed and replaced. 
With reference to FIG. 8, it will be observed by those skilled in the art 
that the relative positions of the guide tracks and the slide plates may 
be reversed. For example, the first guide track may be attached to the 
inking unit, the first slide plate may be attached directly to the press 
frame, and the second guide track may also be attached to the inking unit 
and/or the inking unit and dampening unit combination, and the second 
guide plate may be attached to the press frame. These alternative 
embodiments will not deviate from some of the aspects of the present 
invention. It will be noted in FIG. 8 that the second guide track is 
mounted to the inking unit and provided with a set of a plurality of 
support rollers above the slide plate and which rollers provide support 
against a horizontal surface of the second slide plate. In this 
embodiment, the slide plate is a round bar to advantageously minimize 
space used and maximize clearance and strength. This is the reverse of the 
embodiment shown in FIG. 7, because the direction of action of the weight 
of the inking unit and/or the weight of the inking unit and dampening unit 
combination is in a downward direction. Other combinations of the guide 
tracks attached to the press or to the inking unit, or the slide plates 
attached to the press or inking unit, can be used without departing from 
some of the aspects of the invention. 
Thus, what has been disclosed is a horizontal slide mechanism and system 
for replaceably removing and cleaning inking units on a rotary offset 
printing press. The invention is useable with presses having single or 
multiple color printing capabilities. Inking units can be moved laterally 
out of the sheet path, both for access to the printing cylinders and also 
for cleaning and/or replacement with an inking unit which is set up with 
another desired color. 
Other alterations and modifications of the invention will likewise become 
apparent to those of ordinary skill in the art upon reading the present 
disclosure, and it is intended that the scope of the invention disclosed 
herein be limited only by the broadest interpretation of the appended 
claims to which the inventor is legally entitled.