Sheet delivery device, especially for small offset printing machine

A sheet delivery device for a printing machine wherein a sheet is peeled from an impression cylinder and introduced into a nip formed between two conveyor rollers rolling on one another includes a sheet guiding device located downstream of the conveyor rollers in travel direction of a peeled sheet, guide rollers for a trailing region of the peeled sheet, the guide rollers being in operative engagement with the impression cylinder, a carrying element carrying and uniting the conveyor rollers, the sheet guiding device and the guide rollers into a single unit so that they are adjustable in common therewith to a selected format width, and adjusting means carried by the carrying element for adjusting respective forces of application of the conveyor rollers and the guide rollers.

The invention relates to a sheet delivery device, especially for small 
offset printing machines, wherein a sheet is peeled from an impression 
cylinder and introduced into a gap or nip between two conveyor rollers 
rolling on one another, guide rollers for the trailing part of the sheet 
being peeled from the impression cylinder being associated with the 
impression cylinder in vicinity of the sheet delivery device. 
Sheet delivery devices of the foregoing general type are in use in small 
offset printing machines as well as also, in at least similar form, in 
units or apparatuses for copying, duplicating or printing for office or 
other commercial or business purposes. 
For proper and troublefree paper-sheet delivery, it is necessary that the 
sheet delivery device and various component parts of the sheet delivery 
device, respectively, such as are mentioned hereinbefore, be adjustable, 
respectively, as a whole and with respect to one another. These 
necessities result, for example, from varying format widths and 
thicknesses of the sheets. 
In this respect, the heretofore known state of the art reveals 
disadvantages, especially with regard to operation and adjustability. 
Thus, for example, the format-width is generally adjustable only when the 
printing machine is at standstill; furthermore, the conveyor rollers, 
which are constructed for the most part as profiling and application 
rollers (under their own weight), can be adjusted only individually in 
longitudinal direction of the cylinder, the application pressure between 
the profiling and application roller being nonadjustable, moreover, and 
hence incapable of being matched to the various types of papers. 
In view of these disadvantages of the prior state of the art, it is an 
object of the invention, to provide a sheet delivery device, especially 
for small offset printing machines, which affords simple and problem free 
operation with regard to adjustment of the format-width and the respective 
application pressure of the rollers which are provided and, in addition 
thereto, which ensures gentle handling of the sheet to be delivered. 
With the foregoing and other objects in view, there is provided, in 
accordance with the invention, a sheet delivery device for a printing 
machine wherein a sheet is peeled from an impression cylinder and 
introduced into a nip formed between two conveyor rollers rolling on one 
another, comprising a sheet guiding device located downstream of the 
conveyor rollers in travel direction of a peeled sheet, guide rollers for 
a trailing region of the peeled sheet, the guide rollers being in 
operative engagement with the impression cylinder, a carrying element 
carrying and uniting the conveyor rollers, the sheet guiding device and 
the guide rollers into a single unit so that they are adjustable in common 
therewith to a selected format width, and adjusting means carried by the 
carrying element for adjusting respective forces of application of the 
conveyor rollers and the guide rollers. 
In accordance with another feature of the invention, there is provided 
another carrying element, a respective one of the guide rollers, and one 
of the two conveyor rollers acting as an application roller are arranged 
on each of the carrying elements, one of the carrying elements being 
disposed at a location adjacent the left-hand side of the sheet and the 
other of the carrying elements being disposed at a location adjacent the 
right-hand side of the sheet, the carrying elements being mounted 
laterally slidable and lockable on cross bars extending across the width 
of the printing machine, the other of the two conveyor rollers cooperating 
with the one conveyor roller acting as an application roller and being 
mounted axially displaceably on a drive shaft likewise extending across 
the width of the printing machine, the other conveyor roller being in 
entraining connection with the carrying element. 
In accordance with an added feature of the invention, the carrying element 
is constructed as an elongated bearing block displaceable in axial 
direction on a flattened round shaft and fixable by means of a 
capstan-headscrew, the flattened round shaft being fastened by fastening 
screws to side walls of the printing machine, the carrying element being 
additionally braced by a bifurcated projection on another shaft mounted on 
the two side walls of the printing machine also by means of fastening 
screws. 
In accordance with a further feature of the invention, the entraining 
connection between the other conveyor roller and the carrying element 
comprises a bracket releasably fastened to a lower flattened side of the 
carrying element and embracing the other of the two conveyor rollers. 
In accordance with an additional feature of the invention, there are 
provided adjusting means engaging the carrying element for adjusting and 
displacing the bracket relative to the carrying element in a direction as 
viewed across the width of the printing machine. 
In accordance with again a further feature of the invention, the adjusting 
means comprises knurled nuts engaging a strap of the bracket for laterally 
adjusting the bracket and thus the other conveyor roller with respect to 
the guide roller and the one conveyor roller arranged on the carrying 
element, the knurled nuts being screwed onto a threaded pin engaging in a 
threaded bore formed in the carrying element. 
In accordance with again an additional feature of the invention, the other 
conveyor roller is constructed as a cylindrical rubber roller, and 
including a guide plate for guiding the sheet disposed downstream of the 
other conveyor roller in travel direction of the sheet, the guide plate 
being fastened to a bracket secured to the carrying element. 
In accordance with again an added feature of the invention there are 
provided gears of a drive chain acting upon the drive shaft of the other 
conveyor roller, the other conveyor roller being drivable by the gears. 
In accordance with still an added feature of the invention, the adjusting 
means comprise an adjustable adjusting device operatively associated with 
the one conveyor roller which acts as an application roller, the adjusting 
device being integrated into the carrying element. 
In accordance with still an additional feature of the invention, there are 
provided bearing means for supporting the one conveyor roller by a 
rotational shaft thereof on the carrying element via a first lever 
connected at one end thereof to the rotational shaft, the first lever 
carrying at the other end thereof a bearing pin for the one conveyor 
roller, an application force being transmittable to the other conveyor 
roller from the one conveyor roller via the first lever and the adjusting 
device, the adjusting device including a pin engaging the first lever and 
extending into a bore formed in the carrying element, a compression spring 
engaging the pin for applying the application force thereto, and an 
adjusting screw for presetting the application force in the compression 
spring. 
In accordance with still a further feature of the invention, the guide 
roller is mounted so as to be freely rotatable, respectively, on a second 
lever, the second lever being supported on a bearing pin of the carrying 
element located at a region thereof facing towards the impression 
cylinder, the second lever being resiliently braced against the carrying 
element via another compression spring surrounding a guide pin having a 
nut and locknut threadedly tightened thereon. 
In accordance with a concomitant feature of the invention, there is 
provided a stripping device located adjacent the conveyor rollers for 
peeling the sheet off the impression cylinder, the stripping device 
comprising a rail extending across the width of the printing machine and 
being secured by fastening screws to the side walls of the printing 
machine, the rail having stripper fingers thereon. 
Other features which are considered as characteristic for the invention are 
set forth in the appended claims. 
Although the invention is illustrated and described herein as embodied in a 
sheet delivery device, especially for small offset printing machines, it 
is nevertheless not intended to be limited to the details shown, since 
various modifications and structural changes may be made therein without 
departing from the spirit of the invention and within the scope and range 
of equivalents of the claims.

Referring now to the drawing and first, particularly, to FIG. 1 thereof, 
there is shown a small offset printing press wherein a sheet 5 to be 
printed is isolated or individually separated from a pile 1 and fed to an 
impression cylinder 3 via a feeding device 2. 
Transfer of the printed image occurs in a gap or nip between the impression 
cylinder 3 and a rubber or blanket cylinder 4. The printed sheet 5 is then 
taken over by a sheet delivery device 6 and fed to a delivery pile 7. The 
rubber or blanket cylinder 4 receives the printed image from a plate 
cylinder 8 preceding the blanket cylinder 4, the plate cylinder 8 
receiving the printing ink via an applicator roller 9 which is in contact 
with an inking and dampening unit 10, 11. The printing press receives 
relevant commands from a press operator by way of a control panel 12. 
Other essential component parts of the printing press are a rubber blanket 
washing device 61, a foil infeeding device 62 and an etching device 63. 
FIG. 2 is an enlarged view of the sheet delivery device 6 which is 
associated with the impression cylinder 3. A stripper or sheet remover 13 
is provided for loosening or detaching from the impression cylinder 3 the 
sheet 5 released by sheet grippers 14, and for feeding the sheet 5 to 
conveyor rollers 21 and 22 disposed downstream therefrom. The sheet 
remover or stripper 13 is formed of a plurality of sheet-removing or 
stripping fingers 15 arranged suitably across the width of the machine, 
and carried by a rail 16 with which it is fastened to side walls 17 and 18 
of the printing machine via fastening screws 19 (FIG. 3). After the sheet 
5 has been related by the sheet grippers 14 and the leading edge of the 
sheet 5 has been lifted away, the trailing area of the sheet 5 is held in 
contact with the impression cylinder 3 via a guide roller 20 engaging the 
impression cylinder 3 until the sheet 5 is taken over by the conveyor 
rollers 21 and 22. 
The conveyor rollers 21 and 22, as seen across the width of the sheet, are 
formed as cylindrical rubber rollers 21 and pressure rollers 22 associated 
with the left-hand and right-hand sides of the sheet and being applied 
against the rubber rollers 21 with a given application force. The 
application force is adjustable via a device which is described 
hereinafter in greater detail. 
Respective guide plates 23, arranged on the left-hand and right-hand sides, 
are provided downstream from the conveyor rollers 21 and 22 i.e. 
especially after the rubber roller 21, each of the guide plates 23 being 
of such shape that a slight curvature or bow is imparted to the sheet 5 to 
be delivered so that the inner stability of the sheet 5 is enhanced, 
thereby rendering the further travel of the sheet 5 to the delivery pile 7 
more troublefree. 
The guide roller 20 and the application or the one conveyor roller 22 are 
mounted on a carrying element 24 constructed as an elongated bearing block 
which is displaceable in an axial direction on a somewhat flattened round 
shaft 25 and is fixable by means of a capstan-head screw 26. The flattened 
round shaft 25 is secured to side walls 17 and 18 of the printing machine 
by means of fastening screws or mounting bolts 27. The carrying element 24 
is supported on another shaft 29 by means of a fork-shaped projection 28, 
the mounting support for the shaft 29 being likewise at the two side walls 
17 and 18 and being effected by means of fastening screws or mounting 
bolts 27. 
Each guide roller 20 is furthermore rotatably mounted on a lever 31 which 
is, in turn, pivotable about a bearing pin 32 of the carrying element 24 
and is resiliently or springily braced against the carrying element 24 via 
a compression spring 33, a guide pin 34 and a nut 35 with an associated 
locknut 30 so that the guide roller 20 rests against the impression 
cylinder 3 with a presettable application pressure. 
The mounting support for the application or other conveyor roller 22 on the 
carrying element 24 is also effected by means of an axle or shaft journal 
36 and via a lever 37, the other end of the lever 37 being connected to 
the carrying element 24 via a bearing pin 38. The application force is 
transferred via another lever 60, connected to the bearing pin 38, to the 
application roller 22 via a pin 40 which extends into a bore 39 formed in 
the carrying element 24, a compression spring 41 exerting a biasing force 
on the pin 40. 
The application force can be varied by means of an adjusting screw 42 
acting upon the compression spring 41, the adjusting screw 42 having a 
predetermined adjusting range. The adjusting range extends, for example, 
over less than one turn of the screw. 
A guard plate 44 is provided between the capstan-head screw 26 as well as 
the adjusting screw or setscrew 42 and that region of the sheet delivery 
device 6 facing towards the impression cylinder 3. Ease of access to the 
aforementioned adjusting elements is thereby afforded. 
The rubber roller 21 as well as the guide plate 23 are connected to the 
carrying element 24 by means of a bracket 45. The rubber roller 21 and the 
guide plate 23 are thus laterally displaced simultaneously with the 
application roller 22. The guide plate 23 and the rubber roller 21 can 
moreover by adjusted laterally relative to the application roller 22 by 
means of knurled nuts 46 which act upon a strap 43 of the bracket 45. 
As is apparent from FIG. 4, the knurled nuts are screwed onto a threaded 
rod 47 which engages in a threaded bore formed in the carrying element 24. 
The bracket 45 is releasably mounted on the lower flattened side 49 of the 
carrying element 24 and is accordingly laterally movable and, moreover, 
embraces the rubber roller 21. 
The rubber roller 21, which is provided with a slight sliding fit, is 
mounted on a drive shaft 50 formed with a longitudinal groove 57 and, 
because of the entrainment connection thereof with the bracket 45, can 
readily be displaced in axial direction. 
The drive shaft 50 is mounted in axle or shaft supports 52 through the 
intermediary of ball bearing 51, the shaft supports 52 being secured, 
respectively, to the two side walls 17 and 18 of the printing machine, by 
fastening screws or mounting bolts 53. 
A gear 54 mounted on the drive shaft 50 so as to be fixed against relative 
rotation therewith transmits the rotational movement to the drive shaft 50 
via other gears 55 and 56 of the drive chain. The associated gear 55 is 
rotatably mounted on a bearing pin 59 held in place on the side wall 18 by 
fastening screws or mounting bolts 58. 
By virtue of its construction, as aforedescribed, a material advantage of 
the sheet delivery device according to the invention is, also that all 
adjusting and setting tasks may be performed even while the printing 
machine is in operation. 
The foregoing is a description corresponding in substance to German 
Application No. P 34 13 943.5, dated Apr. 13, 1984, the International 
priority of which is being claimed for the instant application, and which 
is hereby made part of this application. Any material discrepancies 
between the foregoing specification and the aforementioned corresponding 
German application are to be resolved in favor of the latter.