Inking device for a rotary printing machine

An inking device for inking a screen roller of a printing machine includes an ink supply device with an ink reservoir that are removable as one unit from the printing machine easily and without tools. The ink reservoir is separable from the ink supply device. The ink reservoir is filled using an ink cartridge. The printing ink is conveyed under pressure from the ink reservoir to the ink supply device in a supply line. The ink is pressed into the cups or hatchings of the inking device roller via the supply line by using a pump or a conveying roller.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to an inking device for a rotary printing machine 
with a screen roller having an ink supply device arranged on the screen 
roller. The ink supply device is sealed by blades positioned parallel to a 
longitudinal axis of the screen roller. The ink supply device supplies 
printing ink to the circumferential surface of the screen roller and 
carries away ink that is unabsorbed by or wiped away from the screen 
roller. 
2. Description of the Related Art 
A prior art rinsing inking device for a rotary printing machine is 
disclosed in German reference DE 39 11 839 A1. The prior art rinsing 
inking device interacts with a screen roller. A closed chamber is arranged 
below the screen roller bounded by blades on both sides on a 
circumferential surface of the screen roller. A supply device positioned 
between the two blades inside the chamber for supplying printing ink under 
a slight overpressure in an ink application channel. The edges of the 
supply device bordering the screen roller are separated from the screen 
roller on both sides. Printing ink that is not pressed from the ink 
application strip into cups of the screen roller and that drips on the 
outside of the ink application channel, is conveyed under overpressure to 
an ink tank by a suction device. 
A disadvantage of the inking device known from DE 39 11 839 A1 is that ink 
supplied from the ink application channel but not absorbed by the cups of 
the screen roller is not fed back to the ink supply system and is lost. 
A prior art distribution device for printing ink is disclosed in German 
reference DE 33 26 228 A1. The distribution device includes an ink tank 
forming an air-tight seal connected to a line, from which printing ink is 
sprayed under pressure onto inking device rollers. The pressure is 
produced by a pressurized air source that is connected to the ink tank. A 
prefabricated cartridge containing the printing ink is insertable in the 
interior of the tank. 
The disadvantage of this ink supply system is that it is open. When the ink 
is sprayed out, not only are the inking device rollers inked, but the 
surrounding environment is contaminated as well. This necessitates 
expensive cleaning and a high consumption of cleaning agents. Changing the 
ink takes a correspondingly long time, and a large amount of ink is lost 
during the ink change process. 
SUMMARY OF THE INVENTION 
The object of the invention is to provide an improved inking device of the 
aforementioned type such that no printing ink is lost during the inking 
process and that ink changes may be carried out simply and ergonomically. 
This object is attained by an inking device having an ink supply portion 
which supplies printing ink to a screen roller and includes an ink return 
portion which gathers the ink that is applied to the screen roller but not 
absorbed by the screen roller. The ink supply portion and ink return 
portion comprise a closed system. 
The present invention includes a closed system for supplying printing ink 
to the screen roller that minimizes contamination of the ink by paper 
dust, washing agents and the like. Ink changes are made easier by the fact 
that the ink reservoir for the printing ink is designed to be 
exchangeable. Preferably, there is also an exchangeable cartridge for the 
printing ink. Cartridges of this type are manually removable by an 
operator of the printing machine for quick and simple removal without 
requiring any special tools. Because the volume of the ink supply lines is 
very low compared to the volume of the ink reservoir and thus, preferably, 
the volume of the cartridge, only a very small amount of printing ink is 
lost during an ink change. In addition, there is no loss of printing ink 
during printing operations because ink that is supplied by the supply line 
and not absorbed by the screen roller remains inside the closed ink supply 
system and is recycled. The low volume of the supply lines also results in 
lower consumption of cleansing agents and solvents. The invention enables 
ink changes to be carried out quickly and without contamination. Because 
of the low volume of ink in circulation, the invention also provides an 
environmentally-friendly and resource-conserving process for inking a 
printing roller that is simple to clean and which is easily and 
ergonomically handled. 
To facilitate manual handling, the cartridges are designed to be 
light-weight and thus easy to change. The low volume of ink in circulation 
volume permits an accurate determination of the fill level with a constant 
ink supply. If a wetting agent is used, the accurate determination of fill 
level also ensures a constant ink-water balance at all times. 
A farther advantage of the inking device according to the invention is that 
at least one of the pressure under which the printing ink stands in the 
ink supply device is measured or the fill level of the ink is measured. In 
either case, a uniform and continuous supply of ink is ensured. The ink 
filling process inside the inking device is thus monitored and regulated. 
The various features of novelty which characterize the invention are 
pointed out with particularity in the claims annexed to and forming a part 
of the disclosure. For a better understanding of the invention, its 
operating advantages, and specific objects attained by its use, reference 
should be had to the drawing and descriptive matter in which there are 
illustrated and described preferred embodiments of the invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
Referring initially to FIG. 1, an inking device 100 for a printing machine 
(not shown) includes a roller 1 that is inked by an ink supply device 2. 
The roller 1 comprises a screen roller with cups or hatchings and belongs 
to a short inking unit. In the preferred embodiment, the roller 1 rotates 
at machine speed of the printing machine in which the inking device is 
mounted (machine speed is determined by the speed of a form cylinder of 
the printing machine (not shown)). The width of the ink supply device 2 is 
preferably the same as the width of the printing stock web. However, if 
the printing web is 4-pages wide, the ink supply device 2 may also be 
1-page wide or 2-pages wide. Ink supply devices 2 of different page widths 
are thereby interchangeable with each other. The ink supply device 2 is 
supplied with printing ink from an ink reservoir 3 via a supply line 4. 
The ink reservoir 3 preferably has a manually exchangeable ink cartridge 
31. The ink reservoir 3 may be directly attached to the ink supply device 
2, preferably by an easily detachable connection, such, for example, as a 
bayonet lock, a snap lock, or a screw lock 30. In the embodiment shown, 
the ink reservoir 3 is connected to the supply line 4 via the screw lock 
30 which is quickly detachable whenever an exchange of the reservoir 3 is 
required. The ink reservoir 3 includes a cylinder that is pneumatically or 
hydraulically operated by a pressurized medium P supplied through a 
pressure line 5. The piston 6 of the cylinder serves to press printing ink 
into the supply line 4. 
A level monitor 7 is attached to the ink reservoir 3. When a level 7a and a 
level 7b are reached, the level monitor transmits suitable signals via a 
signal line 70 to a control panel 8 of the printing machine. The control 
panel 8 displays the information to ensure that the operating personnel 
are kept aware of the ink level and can anticipate when the ink reservoir 
3 will become empty. 
When the ink reservoir 3 as a whole is removed from the printing machine, 
the connection (e.g., the screw lock 30) between the ink reservoir 3 and 
the ink supply line 4 is detached. At the same time, the connections for 
the pressure line 5 and the signal line 70 are also detached. The ink 
reservoir 3 contains ink cartridge 31 that is exchangeable in a known 
manner and is easily removable from the ink reservoir 3 without the use of 
tools. A quick-release coupling, such, for example, as a bayonet lock may 
be used to connect the cartridge 31 to the ink reservoir 3. The ink 
reservoir 3 may also be removed from the printing machine together with 
the ink supply device 2. 
Newly-supplied printing ink is brought into the cups or hatchings of the 
roller 1 via the supply line 4 under pressure. The portion of printing ink 
that is not absorbed by the cups passes through a gap 9 that runs between 
the circumferential surface of the roller 1 and the inking device 2. The 
direction in which the ink flows through the gap 9 is thereby opposite to 
the rotational direction of the roller 1, so that the cups for the 
printing ink attain a good absorption capacity. The ink that is not 
absorbed by the cups is conveyed through a feedback line 10 to a suction 
pump 11 to be recycled. The suction pump 11 pumps the recycled ink through 
another supply line 12 which directs the recycled ink back to the 
circumferential surface of the inking device roller 1. The supply line 12 
opens at the same position on the surface of roller 1 as the supply line 
4. This measure facilitates the rapid filling of the cups or hatchings of 
the roller 1. 
In addition to the expeditious filling of the cups or hatchings, ink loss 
from the closed system of the ink supply device 2 of the ink reservoir 3 
is also prevented during the inking process. The ink supply device 2 is 
hermetically sealed relative to the roller 1 by a working pre-blade 13, a 
working blade 14 and a closing blade 15. Between the working pre-blade 13 
and the working blade 14, printing ink that overflows from the 
circumferential surface of the inking device roller 1 is also fed back via 
a feedback line 16, which opens into the feedback line 10, to the suction 
pump 11. 
The supply line 12 includes an optional pressure monitor 17 which measures 
the pressure at which the printing ink is applied to the inking device 
roller 1. Alternatively, a fill level monitor may also be provided. The 
pressure monitor 17 or the fill level monitor may work on an optical, 
capacitative, electrical, magnetic or acoustical principle. When the 
pressure monitor 17 senses a pressure below a target level, the pressure 
monitor 17 transmits a signal through a signal line 18 to a valve 19 
located in the pressure line 5. The valve 19 is opened, so that the 
pressurized medium will flow through the pressure line 5 into the 
piston-cylinder unit 6 to increase the pressure applied to the printing 
ink in the ink reservoir 3. A non-return valve 20 in the supply line 4 
prevents the printing ink from flowing back into the ink reservoir 3 if 
the pressure in the supply line 4 ever exceeds the pressure in the ink 
reservoir 3. 
The inking device 100 provides a continuous and uniform supply of printing 
ink to the circumferential surface of the inking device roller 1. 
Therefore, a uniform inking of the roller 1 is ensured. 
As mentioned above, the ink supply device 2 is also easily removed from the 
printing machines during required ink changes. To this end, quick release 
lock, in the form of turn handles 25 are used, which are mounted about 
pivot points 26 inside the printing machine and secure the ink supply 
device 2 on bolts 27. 
Referring now to the embodiment shown in FIG. 2, another ink supply device 
21, like the ink supply device 2, is supplied with printing ink from an 
ink reservoir 3 and inks the inking device roller 1. Like the ink supply 
device 2, the ink supply device 21 has a working pre-blade 13, a working 
blade 14 and a closing blade 15. The working blade 14 is embodied either 
positively or negatively (as shown in FIGS. 1 and 2). The closing blade 15 
is embodied either touching or not touching the inking device roller 1, 
and may also be positioned either positively or negatively. The closing 
blade 15 is preferably embodies in a non-touching manner so that if any 
printing ink remains on the connecting pieces between the cups or 
hatchings of the roller 1 after one rotation, no printing ink will drip 
down laterally on the ink supply device 2. A cavity inside the ink supply 
device 21 is filled with printing ink to a predetermined level by the ink 
supply line 4. A conveying roller 23 located within the ink supply device 
21 rotates opposite to the rotational direction of the roller 1 and 
transports the printing ink to the circumferential surface of the ink 
roller 1 None of the absorbed printing ink is fed back to the ink supply 
inside the ink supply device 21, so that this example, too, has a closed 
ink supply system. The conveying roller 23 serves both to supply printing 
ink to the cups or hatchings of the screen roller 1 and to carry away 
printing ink that is not absorbed by the cups or hatchings. The inking 
device 21 includes a level monitor 24 for monitoring the level 22 of the 
ink in the ink supply device 21. When the ink level 22 falls below a 
predetermined point, the level monitor 24 transmits a low signal via the 
signal line 18 to the valve 19. Valve 19 opens to increase pressure P in 
the ink reservoir 3 so that printing ink from the ink reservoir 3 is 
conveyed via the supply line 4 to the ink supply device 21. 
The following is true for both embodiments shown in FIGS. 1 and 2 of the 
ink supply devices 2 and 21: The roller 1 preferably rotates at the same 
circumferential speed as the form or rubber-blanket cylinders of the 
printing machine. The roller 1 is preferably driven by toothed gears or 
has its own driving motor. The ink supply devices 2 and 21 are embodied in 
the manner of a chamber blade, and may be easily transported without the 
emergence of printing ink. The ink reservoir 3 preferably has an 
exchangeable ink cartridge 31. The ink reservoir 3 itself can also be 
removed easily from the printing machine, preferably by means of a 
quick-release lock between the ink supply device 2, 21 and the ink 
reservoir 3. A non-return valve 20, which prevents ink from flowing back 
into the ink reservoir 3, is preferably provided in the supply line 4. The 
ink reservoir 3 and, with it, the ink cartridge 31, are quickly and simply 
exchanged by a self-closing quick-release coupling, without requiring the 
use of tools. To change the printing ink, the ink supply device 2 and the 
ink reservoir 3 are removed either jointly or separately from the printing 
machine, whereby no tools are needed. A new ink supply device 2 with a 
different printing ink is used instead, which preferably is already 
pre-filled with the new ink. The ink cartridges 31 for the ink reservoir 3 
can be refilled at a fill station. The cartridges 31 are usually refilled 
with the same printing ink and need therefore be cleaned only at long time 
intervals. The ink supply devices 2 and 21 may also be cleaned at a 
cleaning station, where they are turned upside down. After the residual 
ink drips out, this residual ink can either be returned to the ink 
reservoir 3 or fed to a residual ink tank. The ink supply devices 2 and 21 
are embodied in an open manner, allowing them to be cleaned in a suitable 
washing device. 
The working pre-blade 13, the working blade 14 and the closing blade 15, 
respectively, may be positioned either positively or negatively on the 
inking device roller 1. A sensor inside the supply system for the printing 
ink (e.g., the level monitor 7, the pressure monitor 17 or the level 
monitor 24, which can be embodied as pressure sensors, conductivity 
sensors, capacitative sensors or ultrasound sensors, for example) ensures 
that an adequate ink supply is provided at all times and that, in the 
event of ink shortage, the ink cartridge 31 in the ink reservoir 3 is 
changed. The conveying roller 23 of the embodiment shown in FIG. 2, may 
optionally include a torque measuring device, for example, to determine if 
the conveying roller 23 is supplied with a sufficient quantity of printing 
ink at all times. 
The invention includes an ink supply device 2, 21 with an ink reservoir 3 
that is easily removed from the printing machine, cleanly and without 
tools. The ink reservoir 3 is also arranged so that it is separable from 
the ink supply device 2. The quantity of ink in the ink supply device 2, 
21 is minimal. Therefore, at any point in time during operation, there is 
very little printing ink located outside of the ink reservoir 3 that could 
be lost during washing or cleaning. The ink reservoir 3 has an 
exchangeable ink cartridge 31. The printing ink is conducted under 
pressure from the ink reservoir 3 to the ink supply device 2, 21, and 
there pressed into the cups or hatchings of an inking device roller 1 via 
the supply line 4 by means of a pump 11 or a conveying roller 23. The ink 
supply device 2, 21 works with automatic refill of the ink used. When the 
ink is used up, the level monitor 7 sends a message to the control panel 
8. 
The invention is not limited by the embodiments described above which are 
presented as examples only but can be modified in various ways within the 
scope of protection defined by the appended patent claims.