EP1107868A1

EP1107868A1 - Method for cleaning cylinders of a press utilizing press water

Info

Publication number: EP1107868A1
Application number: EP99912382A
Authority: EP
Inventors: C. Robert Gasparrini; Walter H. Cano
Original assignee: Baldwin Graphic Systems Inc
Current assignee: Baldwin Graphic Systems Inc
Priority date: 1998-03-09
Filing date: 1999-03-09
Publication date: 2001-06-20
Also published as: AU3076799A; WO1999046124A1

Abstract

A method of cleaning debris from a cylinder according to the present invention includes operating a dampening water supply system (1) during a cleaning cycle, transferring an increased amount of dampening water (2) to the cylinder to be cleaned, and utilizing an automatic cylinder cleaner to remove the debris from the cylinder.

Description

METHOD FOR CLEANING CYLINDERS OF A PRESS UTILIZING PRESS WATER

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to a new and useful method for cleaning cylinders of a printing press.

More specifically, the invention relates to an improvement in the cleaning of water soluble debris from the cylinders of a printing press by utilizing the existing dampening water supply system to loosen the water soluble debris.

2. Description of the Related Art

It is well known that the printing plate of a lithographic press is chemically treated so that only the printing area is receptive to ink. The non-printing area, on the other hand, is hydrophilic and receptive only to a dampening fluid, such as water. When the dampening water is applied to the plate, the water is rejected on the printing area and is retained by the non-printing area. Consequently, the dampening water retained by the nonprinting area creates a film barrier between the inking rollers and the non-printing area while the printing area, with no film of dampening water, accepts the ink. The ink is then transferred from the printing area of the plate, to the blanket cylinder, and to the paper. The dampening water can be applied by a variety of dampening water supply systems .

One method of categorizing dampening systems is in terms of whether or not a return path for fountain solution exists between the plate cylinder on the printing press and the metering elements of the dampening system. Dampening systems of the brush and spray types contain a physical gap between the means for metering the dampening fluid or fountain solution, and the plate cylinders, and - 2 - as a result, fountain solution can travel in one direction only, that is toward the plate. Thus, dampening systems in this category are referred to as the non-contact or one-way type.

In contrast, dampening systems of the contact type do not contain a physical gap in the path of the fountain solution, thus making it possible for fountain solution to travel to and from between the metering means in the dampening system and the plate cylinder. Thus, this second general class of dampening systems has also been referred to as the two-way, contact, or continuous type dampening system. Regardless of the type of dampening system, the system supplies dampening fluid to the press during the printing cycle.

In order to maintain a high quality of printing, it is necessary not only to control the supply of dampening water and ink during the printing cycle, but also to periodically clean the blanket cylinder of a printing press. Because the cleaning requires the removal of both water soluble debris, such as lint, clay coating, and gum, calcium carbonate, and debris that is insoluble in water, such as ink-based debris, cleaning systems must employ solvents in addition to water. As a result, cleaning the cylinders is complex and time consuming.

In its simplest form, the cleaning is done manually. First, the press operator wipes the cylinder with a cloth dampened with water to remove water soluble debris. Second, the operator wipes the cylinder with a cloth dampened with an ink solvent. In some cases, the wiping cloth is dampened with solvent and water before wiping. Third, after the debris is removed, the operator usually dries the cylinder with a clean cloth. Thus, manual cleaning has the disadvantage of being time consuming . - 3 - o Advancements in the art have led to automatic cylinder cleaners, such as that disclosed by United States Patent No. 4,344,361 to MacPhee et al . (MacPhee et al . ) . The cleaning system disclosed by MacPhee et al . utilizes a cleaning cloth advanced from a cloth supply roll to a 5 cloth take-up roll. Before being wound on the take-up roll, the cleaning cloth is dampened with water and a solvent and is brought into engagement with the cylinder to be cleaned. A bladder, positioned adjacent to the cloth, opposite the cylinder, inflates, thereby bringing

10 the cloth into engagement with the cylinder. The water and the solvent are supplied to the cloth via separate fluid systems and a common tubular member having jets or openings . Although the device of MacPhee et al . has the advantage of automatically cleaning the cylinder with

, minimal down-time, it requires a separate system to supply water to the cylinder to be cleaned.

Other prior art cleaning systems are of the roller or brush type, so named because one or more rubber rollers or brushes remove the debris from the blanket 0 cylinder. The rubber rollers are dampened with a water- solvent mixture. In the roller type, the water-solvent mixture and debris are transferred to a steel roller from which the mixture and debris are scraped by a washup blade or metering roller. Brush types clean directly with 5 debris entering a pan. In roller cleaners or brush cleaners, the water and solvent are normally applied to the rollers in the same manner as applied in automatic cylinder cleaners, namely through a series of conduits, tubes and supply jets. Thus, roller and brush type 0 cleaning systems suffer from the same disadvantage of the automatic cleaners, namely being of complex design due to the separate water supply mechanism. The roller type cleaning system also suffers from the disadvantage of not being very compact and therefore, difficult to install on existing presses. Prior art systems of the brush type also suffer the same disadvantages.

3. Objects of the Invention

It is, therefore, an object of the present invention to provide a new and useful method for cleaning a cylinder of a press.

It is another object of the present invention to provide a method for applying water to effect cleaning a cylinder of a press utilizing either a contact or non-

10 contact dampening water supply system.

It is another object of the present invention to provide a method of cleaning a cylinder of a press that eliminates the need for complex washing fluid supply ,_- systems.

A further object of the present invention is to provide a cleaning method that is easily adapted to existing presses.

A still further object of the present invention 0 is to eliminate the need for a separate water supply system for use in cleaning a blanket cylinder.

Yet another object of the present invention is to eliminate the need for a separate water supply system 5 for use in cleaning a blanket cylinder without manual application of water.

A still further object of the present invention is to provide a method for cleaning a blanket cylinder that is less expensive to manufacture and maintain. 0 Additional objects and advantages of the invention will be set forth in the description that follows and in part, will be obvious from the description, the objects and advantages being realized and obtained by means of the instrumentation, parts, apparata, methods, 5 and procedures particularly pointed out in the appended claims .

4. Summary of the Invention

Briefly described, the method of cleaning debris from a cylinder according to the present invention includes operating a dampening water supply system during a cleaning cycle, transferring an increased amount of dampening water to the cylinder to be cleaned, actuating an automatic cylinder cleaner, and removing the debris from the cylinder.

10

The accompanying drawings, which constitute part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the invention.

15 BRIEF DESCRIPTION OF THE DRAWINGS

It will be understood that the hardware referred to herein, except as specifically described, are known to those skilled in the art and the details thereby are not shown or necessary to the practice of this invention. 20

Figure 1 is a perspective view showing the cylinder cleaning system of the present invention utilizing a contact type dampening system and a blade unit for cleaning the blanket cylinder of the press.

25 Figure 2 is a perspective view showing the cylinder cleaning system of this invention utilizing a dampening system of the non-contact type and an automatic blanket cylinder cleaning apparatus of the cloth type.

Figure 3 is a perspective view showing the

30 cylinder cleaning system of this invention utilizing a non-contact dampening system of the brush roller type and an automatic blanket cylinder cleaning apparatus of the cloth type.

-,_. Figure 4 is a perspective view showing the - 6 - cylinder cleaning system of this invention utilizing a non-contact dampening system of the brush roller type and an automatic blanket cylinder cleaning apparatus of the brush type .

Figure 5 is a perspective view showing the cylinder cleaning system of this invention for use with a sheet-fed printing press having an automatic blanket cylinder cleaning apparatus of the cloth type and an automatic impression cylinder cleaning apparatus of the cloth type.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to Figure 1, there is shown an embodiment of the instant invention for use with a printing press comprising a dampening water supply system 1, a plate cylinder 30, a blanket cylinder 35, and a cleaning unit 70.

The dampening water supply system 1 comprises a dampening water reservoir 5, and a series of rollers 10, 15, 20, 25. The first roller 10 in the series of rollers is partially submerged in the dampening water reservoir 5. Dampening water 2 adheres to the first roller 10 when it is caused to rotate. Dampening water 2, which adheres to the first roller 10, is transferred to the intermediary metering roller 15, the vibrator roller 20 and finally to the form roller 25. The dampening water 2 is so transferred because the rollers 10, 15, 20, 25 are in serial contact with each other. During normal printing operation, the dampening water supply system 1 causes a thin film of dampening water 2 to be transferred from the form roller 25 to the plate cylinder 30. Moreover, during normal printing operation, minimal dampening water is transferred from the plate cylinder 30 to the blanket cylinder 35.

As shown in Figure 1, during the automatic - 7 - o blanket cylinder cleaning cycle, the metering means of the dampening system is energized to provide an increased amount of dampening water 2 that is supplied to the plate cylinder 30, which in turn transfers an increased amount of dampening water 40 to the blanket cylinder 35. Like the rollers 10, 15, 20, 25, the plate cylinder 30 and blanket cylinder 35 are in serial contact, thereby allowing for the transfer of an increased amount of dampening water 40. Once the dampening water 40 reaches the blanket cylinder 35, the dampening water 40 begins to loosen the water-soluble debris, such as lint, clay, and gum, and the like on the blanket cylinder 35. With the water-soluble debris loosened by the dampening water 40, the cleaning unit 70 may be employed.

Generally, the cleaning unit 70 comprises a blade unit 45 which is engagable with the blanket cylinder 35 for scraping the debris therefrom. The debris scrapped from the blanket cylinder 35 is collected in collector 50. As shown in Fig. 1, the blade unit 45 engages the blanket cylinder 35 during the cleaning cycle and solvent is applied. On the other hand, during the printing cycle, the blade unit 45 is disengaged from the blanket cylinder 35. The cleaning unit 70 is described in greater detail in U.S. Patent No. 5,450,792 to Gegenheimer et al . , herein incorporated by reference.

With reference to Figure 2, there is shown an embodiment of the instant invention for use with a printing press having a dampening system 75 of the non- contact type. The dampening water supply system 75 comprises a dampening reservoir 80, a pump 85, a dampening water conduit 90, and a spray nozzle 95. The pump 85 draws dampening water from the reservoir 80 and forces it through the conduit 90 to the nozzle 95 where a spray of fluid 97 is expelled onto the first roller 100 of a series of rollers 100, 105. The dampening water, after being expelled from the nozzle 95, adheres to the first roller 100 and is transferred to the second roller 105, which is in serial contact with the first roller 100. During a normal printing cycle (not shown) , a thin film of dampening water is transferred from the rollers 100, 105 to the plate cylinder 110. On the other hand, during the cleaning cycle, as shown in Figure 2, the present invention involves supplying dampening water to the plate cylinder 110 so that an increased amount of dampening water 120 is transferred to the blanket cylinder 115. Once the increased amount of dampening water is transferred from the plate cylinder 110 to the blanket cylinder 115, the water-soluble debris adhering to the blanket cylinder 115 is loosened. The cleaning unit 145 is thus able to remove the debris. The cleaning unit 145 comprises, generally, a cleaning media 125 wound on a media supply roll 130. During the cleaning cycle, the cleaning media 125 is advanced from the media supply roll 130 to the media take- up roll 135 and is brought into engagement with the blanket cylinder 115 by means of an inflatable bladder or pressure pad 140. The cleaning unit 145 is described with greater detail in U.S. Patent No. 4,344,361 to MacPhee et al., and U.S. Patent No. 4,757,763 to MacPhee et al . , both of which are herein incorporated by reference; however, it should be noted that the present invention provides an improvement over U.S. Patent Nos . 4,344,361 and 4,757,763 in that the cleaning water supply systems disclosed therein are unnecessary in the instant invention.

Additionally, it is noted that the type of cleaning media employed may vary. Generally, the cleaning media will be absorbent to the liquid and solid debris and non-abrasive. In a preferred embodiment, the cleaning media has a reduced air content . Reducing the air content of the cleaning media, for example by calendaring the - 9 - media, produces an elongated web having improved wetability and distribution properties when being saturated with cleaning solvent or a mixture of solvent and water. For example, the cleaning media employed may be of the type and configuration disclosed in U.S. Patent No. 5,368,157 to Gasparrini et al . for A Pre-packaged, Pre- soaked Cleaning System and Method for Making the Same, herein incorporated by reference.

Furthermore, the cleaning media may be impregnated or coated with any number of solvents, for example highly viscous solvents containing a surfactant, emulsified water, or polyethylene glycol .

With reference to Figure 3, there is shown an embodiment of the instant invention for use with a press having a non-contact dampening supply system 150 of the brush-roller type.

The dampening supply system 150 comprises a fountain pan roller 165 partially submerged in a pan 155 holding fountain or dampening water 160. In operation, the fountain pan roller 155 and a brush roller 170 rotate as illustrated by the arrows in Fig. 3. The bristles 172 of the brush roller 170 flick the dampening water 175, which had adhered to the fountain pan roller 165, across a gap 177 and onto a first roller 180. The dampening water is transferred to the form roller 185, which is a serial contact with both the first roller 180 and the plate cylinder 190. During normal printing operations, minimal dampening water is transferred to the blanket cylinder 195; however, during the cleaning cycle of the instant invention, an increased amount of dampening water 200 is transferred from the plate cylinder 190 to the blanket cylinder 195. The dampening water 200 that is transferred to the blanket cylinder 195 serves to loosen the water- soluble debris adhering thereto. - 10 - Once the water-soluble debris has been loosened by the dampening water 200, the cleaning unit 205 removes the debris from the cylinder 195. The cleaning unit 205 is similar to that described with regard to Fig. 2 in that a cleaning media 210 is advanced from a supply roll 215 to a take-up roll 240. Interposed between the supply roll 215 and take-up roll 240 is a mechanism 235, such as an inflatable bladder, for causing the media 210 to engage the blanket cylinder 195. The media 210 removes the debris before being taken-up on the take-up roller 240. Unlike the cleaning unit 145 described with regard to Fig. 2, the cleaning unit 205 of Fig. 3 employs a soak-on-press type arrangement. In general, before the cleaning media 210 engages the blanket cylinder 195, the cleaning media 210 is submerged in a solvent or cleaning agent 220 in a container 215. In order to submerge the cleaning media 210, the media 210 is brought underneath a dipping roller 225, which is partially submerged in the solvent 220. After being submerged, the cleaning media 210 is run between a pair of squeezing rollers 230 which serve to remove any excess solvent from the media 210 before it is brought into engagement with the blanket cylinder 195.

An alternative embodiment of the present invention will now be described with reference to Fig. 4, and continuing reference to Fig. 3. As shown, the embodiment of Fig. 4 employs the same dampening supply system 150 of the embodiment shown in Fig. 3. It is to be understood, however, that neither embodiment is limited to the dampening supply system shown. The dampening supply system 150 is operated as described above, so that an increased amount of dampening water 200 is transferred to a blanket cylinder 195.

Once the water-soluble debris adhering to the blanket cylinder 195 has been loosened by the dampening - 11 -

° water 200, the cleaning unit 300 removes the debris.

Specifically, the cleaning unit 300 is of the brush type, including a rotating brush 310 mounted inside a housing 320. In operation, a brush 310 engages the blanket cylinder 195. By rotating, a brush 310 separates the 5 debris from the blanket cylinder 195. A vacuum system, not shown, draws the separated debris from the housing 320 via conduit 340. Liquid collects in a pan with more solid debris and is removed by a drain pipe to a receptacle . Flexible wipers 330 engage the blanket cylinder 195,

J0 thereby providing a sealing surface with the blanket cylinder 195. During a printing cycle, an actuator, not shown, disengages the brush 310 and wiper blades 330 from the blanket cylinder 195. Operation of automatic blanket cleaners of the brush type are described in greater detail

₁₅ in U.S. Patent Nos . 4,972,780, 5,086,701, 5,265,537, and 5,322,015 to Gasparrini et al . , the disclosures of which are herein incorporated by reference.

Turning now to Figure 5, there is shown an embodiment of the instant invention for use with a sheet- 0 fed printing press. In general, the press includes a dampening water supply system 400, an ink supply system 425, a plate cylinder 450, a blanket cylinder 455, and an impression cylinder 460. The blanket cylinder 455 has associated therewith an automatic blanket cylinder cleaner 5 of the cloth type 465, and the impression cylinder 460 as associated therewith an automatic impression cylinder cleaner of the cloth type 470. It is to be understood that the distance between the blanket cylinder 455 and the impression 460 is variable depending upon the thickness of 0 the paper stock used, and, indeed, the two cylinders 455, 460 may be brought in contact with each other.

As discussed above with reference to Fig. 1, the dampening water supply system 400 comprises a dampening water reservoir 405 and series of rollers 410, 415, 420 5 - 12 - which are in serial contact with the plate cylinder 450. The dampening water adheres to each of the rollers 410, 415, 420 and is thus transferred to the plate cylinder 450. During normal printing operations, a thin film of dampening water is supplied to the plate cylinder 450 which, in turn, transfers little dampening water to the blanket cylinder 455.

Similarly, the inking system 425 comprises an ink pan 430 and a series of rollers 435, 440, 445 which are in serial contact with the plate cylinder 450. As with the water dampening supply system 400, the ink adheres to the rollers 435, 440, 445 and is thus transferred to the plate cylinder 450.

According to the present invention, during the automatic blanket cylinder cleaning cycle, the inking system 425 is turned off and no paper is fed through the press. Moreover, an increased amount of dampening water is supplied via the dampening water supply system 400 to the plate cylinder 450. The increased amount of dampening water is transferred to the blanket cylinder 455 where it begins to loosen the water-soluble debris. Having loosened the debris, the automatic blanket cylinder cleaner 465 is actuated to clear the blanket cylinder 455.

Because the impression cylinder 460 is equipped with an automatic impression cylinder cleaner 470, cleaning of the impression cylinder 460 may also take advantage of the increased amount of dampening water supplied in accordance with the present invention. Specifically, the amount of dampening water supplied to the press during the cleaning cycle is increased to such a level that the impression cylinder 460 also receives the increased amount of dampening water. The impression cylinder 460 receives the increased amount of dampening water either by the dampening water traversing the space between the blanket cylinder 455 and the impression - 13 - cylinder 460, or by the repositioning of the impression cylinder 460 so that it is in serial contact with the blanket cylinder 455. Once the dampening water reaches the impression cylinder 460, the dampening water loosens the water-soluble debris, and the automatic impression cylinder cleaner 470 is actuated to remove the debris.

In an alternate embodiment, in which the press does not include an automatic impression cylinder cleaner, the cleaning cycle is preceded by positioning the impression cylinder 460 away from the blanket cylinder 455 so that no water is transferred to the impression cylinder 460. Cleaning of the blanket cylinder 455 then proceeds as discussed above.

It is to be understood that the order of cleaning the blanket cylinder 455 and the impression cylinder 460 may be varied. For example, a blanket cylinder 455 may be cleaned first, followed by cleaning of the impression cylinder 460, or vice versa.

Alternatively, the blanket cylinder 455 and the impression cylinder 460 maybe cleaned at the same time.

Regardless of the particular embodiment of the present invention that is employed, the impression cylinder 460 is returned to a position appropriate for the next printing cycle. It has been found that operating the existing dampening water supply system of a press at increased or near full capacity for a selected interval results in the desired amount of dampening water being transported to the cylinder to be cleaned. Thus, in the embodiments shown in Figs. 1, 2, 3, 4, and 5 operating the dampening supply system 1, 75, 150, 400 at increased or near full capacity provides the proper amount of water to an automatic blanket cleaning cycle using automatic blanket cleaners of the cloth, brush, and blade type to effect cleaning. - 14 - Controlling the dampening system to provide the proper amount of water may include operating the supply system for a predetermined interval, at a predetermined rate, by repeatedly turning the system on and off, or by a control system whose input is the actual amount of dampening water as measured in the press. Furthermore, the dampening water supply system can be controlled according to the volume and rate of water supplied. Control of dampening and fountain fluid supply systems are described in greater detail in U.S. Patent No. 4,724,764, herein incorporated by reference.

It should be noted that the amount of dampening water that constitutes an increased amount varies greatly depending upon the size and type of press involved, as well as the type of stock run. It follows that the duration for which a particular dampening supply system must operate to achieve an increased amount varies greatly as well.

Although this invention has been described in terms of certain preferred embodiments, other embodiments that are apparent to those of ordinary skill in the art are also intended to be within the scope of this invention. For example, the embodiment shown in Figure 1 could be employed with the automatic blanket cylinder cleaning system 145 shown in Figure 2. Combinations of automatic cylinder cleaning systems with contact and non- contact type dampening systems are thus effective for the addition of an increased amount of water to a cylinder cleaning cycle. Additionally dampening systems can operate in the same manner on web presses to supply water for cleaning. These presses may or may not have an impression cylinder. For example, some print blanket cylinder to impression cylinder while others print blanket to blanket. Thus, it is within the scope of the present invention to utilize any automatic cylinder cleaner, with - 15 - any dampening water supply system, on any type of press, including web and sheet -fed, and for the cleaning of any cylinder, including plate, blanket, and impression cylinders. Accordingly, the scope of the present invention is intended to be limited only by the claims appended hereto.

Claims

- 16 -We claim:

1. A method for automatically cleaning debris from a cylinder of a press, using an automatic cylinder cleaner, the method comprising the step of:

operating a dampening water supply system to supply the press with an increased amount of dampening water during an automatic cylinder cleaning cycle.

2. The method of claim 1 wherein supplying the press with said increased amount of dampening water comprises operating said dampening water supply system for a selected interval .

3. The method of claim 2 wherein said dampening water supply system is operated at substantially full capacity during said selected interval.

4. The method of claim 1 wherein the automatic cylinder cleaner comprises a cleaning cloth wound on a cloth supply roll affixed to the press, and wherein the method further comprises the step of engaging said cloth with the cylinder to be cleaned.

5. The method of claim 4 wherein the cloth has a reduced air content .

6. The method of claim 4 wherein the cloth is pretreated with a cleaning agent.

7. The method of claim 1 wherein the automatic cylinder cleaner comprises a blade unit and wherein the method further comprises the step of engaging said blade unit with the cylinder to be cleaned. - 17 -

8. The method of claim 1 wherein the automatic cylinder cleaner comprises a brush and wherein the method further comprises the step of engaging said brush with the cylinder to be cleaned.

9. The method of claim 1 wherein the cylinder to be cleaned is a blanket cylinder.

10. The method of claim 1 wherein the cylinder to be cleaned is a plate cylinder.

11. The method of claim 1 wherein the cylinder to be cleaned is an impression cylinder.

12. The method of claim 11 further including the step of cleaning a blanket cylinder.

13. The method of claim 12 wherein the blanket cylinder and the impression cylinder are cleaned at the same time.

14. The method of claim 11 wherein the press includes a blanket cylinder and wherein the method further includes the step of positioning the impression cylinder in contact with the blanket cylinder.

15. The method of claim 1 wherein the step of operating the dampening water supply system includes repeatedly turning the dampening system on and off.

16. The method of claim 15 wherein the dampening system is turned on and off at selected intervals .

17. The method of claim 1 wherein the step of operating the dampening water supply system during the o cleaning cycle includes first operating the dampening system and then energizing the automatic cylinder cleaner.

18. The method of claim 1 wherein the step of operating the dampening system includes turning the dampening system on continuously.

19. The method of claim 1 further including the step of operating the dampening system during a subsequent cleaning cycle, wherein operation of the dampening system during the cleaning cycle differs from operation of the dampening system during the subsequent cleaning cycle.

20. The method of claim 19 wherein operation of the dampening system differs in duration.

21. The method of claim 19 wherein operation of the dampening system differs in capacity.

22. The method of claim 1 wherein the press includes two blanket cylinders and the method further includes the step of cleaning the cylinders simultaneously .

23. The method of claim 22 wherein the cylinders are cleaned simultaneously.