Inking unit for printing presses

Abstract

An inking unit for printing presses, preferably offset printing presses, can have a plurality of plate-inking rollers for inking a plate cylinder along with a multiplicity of inking rollers. The inking rollers can be positioned to supply ink flow, in at least two directions to the plate-inking rollers. The inking rollers and the plate-inking rollers can then form a closed chain of rollers, and can enclose a space therebetween. A measuring device can be provided to monitor the temperature of the air within this space, with measured values being used for control of the temperature of the inking unit.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an inking unit for printing presses, and preferably offset printing presses. Such printing presses typically can have a plurality of inking rollers for supplying ink to a plurality of plate-inking rollers that ink a plate on a plate cylinder. The inking rollers are generally positioned before the plate-inking rollers and supply the ink to the plate-inking rollers. The inking rollers can also be arranged so that the ink flow provided by the inking rollers is split into two directions of supply. With such a configuration, the inking rollers can, together with the plate-inking rollers, form a closed chain of rollers that enclose a space therebetween.

2. Background Information

In high-speed printing presses, the inking unit can heat up significantly during production printing of a large number of copies. As the inking unit heats up, the viscosity of the ink can be changed as a result of the fluctuations in the temperature. German Patent No. 19 53 590 A1, which corresponds to U.S. Pat. No. 3,741,115, describes an inking unit that is temperature-regulated by means of regulation of the temperature of the damping solution. This German reference utilizes a generally well-known cooling device, which is controlled through the intermediary of a temperature sensor.

In another method of controlling the temperature of an inking unit, disclosed in German Patent No. 27 59 351 C2, apparatus is provided for controlling the temperature of the printing ink. Such a device can be used in order to prevent inking fluctuations in the inking unit of the printing press.

However, the temperature sensors provided in the known apparatuses are generally provided either in the coolant circuit or directly on the ink tank itself. As such, the measured temperature values provided by such known arrangements do not directly indicate the temperature values existing in the inking unit itself. Since the inking unit provides the ink distribution necessary to provide high quality prints, any temperature fluctuations in the unit itself could adversely affect the print quality, unless such changes are quickly identified and remedied. Thus, with the known configurations for controlling temperatures, it is essentially not possible for temperature adjustments, or influences of the temperature control, to be matched precisely to the requirements of the inking unit, as the inking unit temperatures are not measured.

In summary, one aspect of the invention resides broadly in a printing press comprising a plate cylinder, damping apparatus for applying a wetting agent to at least the plate cylinder, the damping apparatus comprising a reservoir for storing the wetting agent, and an inking unit for applying ink to the plate cylinder. The inking unit has an ink reservoir for storing the ink, and the inking unit comprises a plurality of plate-inking rollers disposed in contact with the plate cylinder to apply ink to the plate cylinder, a plurality of inking rollers disposed between the ink reservoir and the plate inking rollers to transfer ink from the ink reservoir to the plate inking rollers. The plurality of inking rollers defines at least two ink supply paths for supplying ink to the plate-inking rollers at at least two locations of the plate-inking rollers, and the inking rollers and the plate-inking rollers form and substantially enclose a space therebetween. The inking unit further comprises a device for extracting air from the substantially enclosed space, a temperature sensor device for measuring a temperature of the extracted air, a device for regulating a temperature of at least one of: the inking unit, and the wetting agent, and control apparatus for receiving the measured temperature from the temperature sensor device and operating the device for regulating based on the measured temperatures of the extracted air.

Another aspect of the invention resides broadly in a method for monitoring and controlling temperature in an inking unit of a printing press, wherein the printing press includes: a plate cylinder; damping apparatus for applying a wetting agent to at least the plate cylinder, and an inking unit for applying ink to the plate cylinder. The inking unit has an ink reservoir for storing the ink, and the inking unit comprises: a plurality of plate-inking rollers disposed in contact with the plate cylinder to apply ink to the plate cylinder; a plurality of inking rollers disposed between the ink reservoir and the plate inking rollers to transfer ink from the ink reservoir to the plate inking rollers; a device for extracting air from an area adjacent the plate-inking rollers and the inking rollers; temperature sensor apparatus for measuring a temperature of the extracted air; a device for regulating a temperature of at least one of: the inking unit, and the wetting agent; and control apparatus for receiving measured temperatures from the temperature sensor device and operating the device for regulating based on the measured temperatures of the extracted air. The method comprises the steps of: transferring ink within the inking unit from the ink reservoir to the plate-inking rollers, the inking unit having a temperature; transferring wetting agent from the wetting agent reservoir to at least the plate cylinder, the wetting agent having a temperature; extracting air from the area adjacent the inking rollers and the plate-inking rollers; measuring a temperature of the extracted air with the temperature sensor device; and adjusting at least one of: the temperature of the inking unit, and the temperature of the wetting agent to bring the measured temperature into correspondence with a predetermined temperature.

A further aspect for the invention resides broadly in an inking unit for a printing press, the printing press having a plate cylinder and damping apparatus for applying a wetting agent to at least the plate cylinder, the damping apparatus comprising a reservoir for storing the wetting agent, and the inking unit for applying ink to the plate cylinder. The inking unit comprises an ink reservoir for storing the ink, a plurality of plate-inking rollers for being disposed in contact with the plate cylinder to apply ink to the plate cylinder; a plurality of inking rollers disposed between the ink reservoir and the plate-inking rollers to transfer ink from the ink reservoir to the plate-inking rollers; the plurality of inking rollers defining at least two ink supply paths for supplying ink to the plate-inking rollers at at least two locations of the plate-inking rollers; the inking rollers and the plate inking rollers forming and substantially enclosing a space therebetween; a device for measuring a temperature of air of the substantially enclosed space; apparatus for regulating a temperature of at least one of: the inking unit, and the wetting agent; and control apparatus for receiving measured temperatures from the temperature sensor device and operating the apparatus for regulating based on the measured temperatures of the extracted air.

OBJECT OF THE INVENTION

The object of the present invention is therefore to improve the printing conditions by improving regulation of the temperature when fluctuations in temperature occur.

SUMMARY OF THE INVENTION

The object of the invention is essentially achieved by providing a means for the extraction of air from the space formed between the inking rollers and the plate-inking rollers, and by routing the extracted air past a temperature sensor to monitor the temperature at the inking unit. The measured values determined by the temperature sensor can then preferably be displayed and/or sent, as measured variables, to a temperature-control apparatus. The temperature control apparatus can be configured to control the temperature of the inking unit and/or the damping-solution supply.

This design according to the present invention makes it possible to perform the continuous measurement of the temperature directly in the inking unit, without the printing process being influenced by the measurement. Furthermore, the measurement is essentially done by contactless means, that is, preferably no parts of the measuring device contact any of the working portions of the inking unit. Thus, the measured values can preferably be used for the continuous temperature control of the inking unit or for regulation of the temperature of the damping-solution supply, without the measurement being distorted by external influences.

According to an advantageous embodiment of the invention, the means for the extraction of the air can preferably be in the form of a tubular cross-member disposed between the side frames of the press. The tubular cross-member can then preferably have, viewed in the length, or axial direction of the rollers, at least one suction opening in the central region thereof. Alternatively, the tubular cross-member could have other configurations of suction openings depending on the desired temperature sensing positions.

A temperature sensor can preferably be provided within the tubular cross-member in the flow direction of the extracted air, so that the extracted air is passed over the sensor to provide a determination of the temperature in the inking unit itself. With such an arrangement, a permanent, small air flow can be extracted from within the inking unit, and thus, by using relatively few devices, there can be essentially optimal adjustment of the inking-unit temperature control and/or of the temperature control of the damping-solution supply to provide an essentially stable temperature in the inking unit.

Alternatively, an inking unit could also be provided with more than one tubular cross-member in the enclosed space. If more than one member was present, the individual cross-members can preferably be placed in a spaced apart configuration to thereby provide a number of temperature readings across the enclosed space. The temperature readings could then preferably be averaged to yield an averaged temperature profile for the respective inking unit, which averaged value could preferably be used to make temperature adjustments. Alternatively, if so desired, instead of averaging values to control a single temperature, individual temperature sensors could supply temperature readings for controlling temperatures in specific locations of the printing press.

In addition, the configuration according to the present invention also provides the advantage that with the continuous volumetric flow of the extracted air out of the inking unit, essentially no heat buildup can be possible at high inking-unit temperatures, as the air within the inking unit can essentially be continuously replaced.

BRIEF DESCRIPTION OF THE DRAWINGS

An advantageous embodiment of the present invention is shown in the accompanying drawings, in which:

FIG. 1 shows a side view of an inking unit with a tubular cross-member;

FIG. 2 shows a longitudinal section through the tubular cross-member;

FIG. 3 shows an alternative side view of the inking unit with one configuration of temperature control apparatus; and

FIG. 4 shows a schematic representation of one possible arrangement of electrical connections for the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In a printing press, the plate cylinder 1, shown in FIG. 1, can typically be arranged in association with an inking unit 2 and a damping unit 3. In the specimen embodiment shown, the inking unit 2 preferably has four plate-inking rollers 4, 5, 6 and 7. The ink can preferably be carried from the ink reservoir 30 to the plate-inking rollers 4-7 by means of a multiplicity of inking rollers generally indicated as 8. In the region of the inking roller 9, the ink flow can preferably be split into preferably at least two directions of supply. In a first direction, the ink can preferably be distributed from the inking roller 10 onto preferably the first two (as viewed in the direction of rotation of the plate cylinder 1) plate-inking rollers 4, 5. In a second direction, the ink can preferably be distributed from the inking roller 11 and the following inking rollers, ending with inking roller 10A, onto the last two (as viewed in the direction of rotation of the plate cylinder 1) plate-inking rollers 6 and 7. As shown in this embodiment, the inking rollers 9, 10, 10A, 11 and any intermediary inking rollers up to the plate-inking roller 6 can form, in conjunction with the plate-inking roller 5 and the intermediate roller 12, a closed chain of rollers, which encloses a space 13.

It should generally be understood that alternative configurations of rollers can also be possible which provide possibly more than one enclosed space, possibly an enclosed space which is defined on one side by the plate cylinder itself, i.e. if rollers 5, 6 and 12 were not present, or possibly no enclosed space if only one ink path were present, i.e., if only rollers 9, 10, 4 and 5 were present. The embodiments as discussed below could generally apply to each of the roller configurations herein referred to.

Provided in the space 13 there can preferably be a tubular cross-member 14, which can extend, as shown in FIG. 2, between the two side frames 15, 16. As a variation thereon, the tubular cross-member could also be attached to only one side frame and project a distance away from the side member to preferably about the center 17 of the press. In the shown embodiment, the tubular cross-member 14 can preferably be attached to both printing-press side frames and can preferably have at least one suction opening 18 approximately in the center 17 of the press. An air flow can then preferably be extracted through the suction opening 18 and through the interior of the tubular cross-member 14. The cross-member 14 can preferably be connected to a suction device (not shown) by means of intermediary air tube 19.

Provided in the tubular cross-member 14, in the path of air flow of the extracted air, there can preferably be a sensor 20, which, acting as a temperature sensor, determines measured temperature values. The measured data can then preferably be sent, via lines 21, to a display unit 22. Alternatively, for automatic control of the temperature within the inking unit, the measured data values can preferably be sent to a temperature-control apparatus of the inking unit (see FIG. 4). The suction apparatus and the temperature-control apparatus can essentially be any type of known devices, and have essentially not been shown in the drawing.

As alternative embodiments, if more than one enclosed space were present, individual corresponding temperature sensors could be positioned to read temperatures in each enclosed space, or a cross-member 14 could be disposed within each enclosed space to withdraw air from each enclosed space to either a common temperature sensor 20, or a corresponding temperature sensor 20 for each cross-member 14. On the other hand, if there were no enclosed spaces formed between the rollers, the temperature sensor 20 could be disposed in the vicinity of the inking rollers and plate-inking rollers. In such an embodiment, any tubular member 14 could merely be disposed adjacent the rollers to extract air from the vicinity of the rollers.

As depicted by FIGS. 3 and 4, the measured temperature values can be sent to a control device which can preferably analyze the measured values to determine if a temperature adjustment needs to be made. Upon determining that an adjustment of temperature is needed, the controller can preferably send a signal to the temperature control apparatus 24 of the damping solution supply and/or the temperature control apparatus of the inking unit, which could be a device 27 for cooling the ink stored in the ink reservoir 30. In addition, the controller could also conceivably monitor the temperatures of the damping solution and the ink by means of temperature sensors 26 and 27. By monitoring the temperatures of the damping solution and ink, the controller could determine whether a cooling has been brought about at the desired device, or insure that excessive cooling does not occur at the desired device. Thus, a feedback loop can preferably be established to monitor the temperatures and provide adjustments where necessary.

Further, while the disclosed embodiment of the present invention is discussed as a temperature control, it is conceivable that such a monitoring and adjustment arrangement could also apply to other operating parameters, i.e. air flow for possibly determining whether an air filter is clogged, or humidity, etc. if such parameters have an effect on the overall printing quality.

One feature of the invention resides broadly in the inking unit for printing presses, preferably offset printing presses, with a plurality of plate-inking rollers for inking a plate cylinder and with a multiplicity of inking rollers, said inking rollers being positioned before the plate-inking rollers and supplying the ink to them, with the ink flow being split into two directions of supply and with the inking rollers enclosing a space together with the plate-inking rollers as a closed chain of rollers, characterized in that a means for the extraction of air is provided in the space 13; the extracted air is routed past a temperature sensor 20; and the measured values determined by the temperature sensor 20 are displayable and are sent as controlled variables to the temperature-control apparatus of the inking unit 2 and/or to the damping-solution supply.

Another feature of the invention resides broadly in the inking unit, characterized in that the means for the extraction of air is in the form of a tubular cross-member 14 between the side frames 15, 16, said tubular cross-member 14 comprising, viewed over the length of the rollers, suction openings 18 in the central region 17, and in that a temperature sensor 20 is provided in the tubular cross-member 14 in the flow of the extracted air.

All, or substantially all, of the components and methods of the various embodiments may be used with at least one embodiment or all of the embodiments, if any, described herein.

The invention as described hereinabove in the context of the preferred embodiments is not to be taken as limited to all of the provided details thereof, since modifications and variations thereof may be made without departing from the spirit and scope of the invention.

Reference List

1 Plate cylinder

2 Inking unit

3 Damping unit

4 Plate-inking roller

5 Plate-inking roller

6 Plate inking roller

7 Plate inking roller

8 Inking rollers (general)

9 Inking roller

10 Inking roller

10A Inking roller

11 Inking roller

12 Intermediate roller

13 Space

14 Tubular cross-member

15 Side frame

16 Side frame

17 Center of press

18 Suction openings

19 Air tube

20 Sensor

21 Electrical Lines

22 Display unit

24 Temperature sensor

25 Temperature control device

26 Temperature sensor

27 Temperature control device

30 Ink reservoir

Claims