Inking Apparatus Having Automatic Wash-up Means

Abstract

An inking unit, including an ink fountain formed between an inking cylinder and a scraper type doctor blade, is provided with an automatic wash-up system. The latter includes spray pipes having nozzles that direct cleansing and rinsing fluids against the ink engaging elements. Much of these cleansing and rinsing fluids are recirculated to prevent waste, with recirculating being effected by the same pump that delivers ink to the reservoir from which ink is supplied to the fountain.

Description

This invention relates to inking units for printing apparatus and more particularly relates to an automatic wash-up system for the inking unit.

U. S. Pat. No. 3,630,146, issued Dec. 28, 1971, to A. F. Shields, for an Interruptable Inking Cylinder and Scraper Blade Forming Open Ended Fountain Trough illustrates an inking device in which a fountain is formed through the cooperation of an inking cylinder, a scraper type doctor blade and a support for the latter.

Whenever it becomes necessary to change the color of the ink being used, all of the ink contacting elements must be washed clean before the new color ink is introduced to the inking apparatus. Not only does this wash-up usually require extensive down time for the printer and associated equipment, but the job requires much operator time, is a very dirty task, and is often not performed to a desirable degree.

Accordingly, the instant invention provides an automatic wash-up system for inking apparatus including spray pipes that are strategically located for the proper application of cleansing and rinsing fluids, so that the inking cylinder, the doctor blade, and the other fountain forming elements are effectively cleaned in a short period of time without the utilization of manpower.

Thus, a primary object of the instant invention is to provide novel apparatus for automatically washing inking apparatus used for printing and coating equipment.

Another object is to provide automatic wash-up apparatus of this type that is not wasteful of cleansing and/or rinsing fluids.

A further object is to provide automatic wash-up apparatus of this type in which cleansing and rinsing fluids are circulated through the system by the same pump that delivers ink to the ink supply reservoir.

These objects as well as other objects of this invention will become readily apparent after reading the following description of the accompanying drawings in which:

FIG. 1 is a perspective illustrating, in simplified form, an inking unit and an automatic wash-up system therefor, the latter being constructed in accordance with teachings of the instant invention.

FIG. 2 is a cross-section taken through line 2--2 of FIG. 1, looking in the direction of arrows 2--2.

FIG. 3 is a diagram of the operational selector and the programmer for the automatic wash-up system.

FIG. 4 is a program chart showing the operational intervals for the elements of the wash-up apparatus.

Now referring to the figures. The inking elements of FIG. 1 are generally of a type described in the aforesaid U. S. Pat. No. 3,630,146 and include elongated inking cylinder 11 mounted for rotation on axial extensions 12, 13. Cylinder 11, together with elongated scraper blade 15 and its open-ended support 16 of generally V-shaped cross-section, define trough-like ink fountain 14 (FIG. 2). Clamping element 17 removably secures blade 15 to support 16. Ink catcher or drip pan 18 is positioned below cylinder 11 and the elements defining fountain 14 to catch ink flowing out the open ends of fountain 14. Flexographic printing ink is supplied to fountain 14 at the center thereof by nozzle 19. Conduit 21, having normally closed solenoid operated valve C therein, connects nozzle 19 to the outlet at the bottom of ink reservoir 22.

Upper and lower spray pipes 23, 24 extend parallel to the longitudinal axis of cylinder 11 for substantially the full length thereof. The respective conduits 25, 26 connect pipes 23, 24 to different legs of Y-connector 27. The latter is joined to one leg of T-connector 28, another leg of which is connected through conduit 29 to spray head 30 at the top of reservoir 22. The third leg of connector 28 is connected to the outlet of the section 31 of the wash-up system from which fresh water and a detergent are obtained.

Section 31 includes fresh water inlet 32 connected through manually operated inlet valve 33, pressure gauge 34, and strainer 35 to the upstream end of normally closed solenoid operated fresh water valve G, whose downstream end is connected through normally closed solenoid operated detergent valve S to outlet coupler 36 of section 31. Line 37, having manually operated water bypass valve 38 therein, is connected across the series combination of solenoid operated valves F and G. Line 39, having detergent injector 41 therein, bypasses solenoid operated valve F. The inlet of injector 41 is connected to detergent supply 42. The action of injector 41 is such that when a full head of water flows therethrough, detergent is drawn from supply 42, is mixed with the water, and the mixture is delivered to outlet coupler 36. Thus, when valve F is closed and valve G is open, injector 41 will act to mix detergent with water. However, when both valves F and G are open, the head of water at injector 41 will be insufficient to draw detergent from supply 42 and only fresh water will appear at outlet coupler 36.

Catcher pan 18 is provided with gravity drain 43 connected through line 44 to the inlet of pump 45. The downstream end of conduit 44 is provided with residual water drain line 46 having normally closed solenoid operated drawn valve D therein. The outlet end of pump 45 is connected through solenoid operated ink return valve A and line 47 to ink reservoir 22, and the downstream end of valve A is connected to wash water drain line 48 through solenoid operated sewer drain valve E. The upstream end of valve C is connected through solenoid operated ink drain valve B to the inlet of ink drain bucket 51. The upstream ends of both valves B and C are connected through manually operated valve 52 to manual ink drain line 53.

Longitudinally spaced nozzles 56 on upper spray pipe 23 direct fluid from pipe 23 into fountain 14. The lower spray pipe 24 is provided with two sets of longitudinally spaced nozzles 57 and 58. Nozzles 57 direct fluid directly against the lower surface of scraper blade 15 at the nip region along the line of contact between the free edge of scraper blade 15 and periphery of cylinder 11. The other nozzles 58 direct fluid against the periphery of rotating cylinder 11 at the region below and in the vicinity of the line of contact between blade 15 and cylinder 11.

Energization of solenoid operated valves A-G takes place in a controlled sequence, established by programmer 60 (FIG. 3). The latter is preferably a stepping drum-type device of a type manufactured and sold by the Tenor Company, 17020 West Rogers Drive, New Berlin, Wisc. A choice of programs is obtained by utilizing selector 61. The latter includes two-position switch 62 for choosing long or short washing cycles and another two-position 63 for placing the doctor blade in its wash or run position. In the wash position doctor blade 15 rests against cylinder 11, and in the run position blade 15 is slightly spaced from cylinder 11 so that an ink film of controlled thickness is formed on cylinder 11. Selector 61 also includes start and stop control buttons 64, 65, respectively.

The references R-1 through R-5 designate timing periods established by sections of programmer 60. As seen in FIG. 4, timing period R-1 is 80 seconds, and timing period R-5 is 5 seconds. However, programmer 60 is so constructed that when more than one of thetime interval sections is actuated, the timing interval is the sum of the individual intervals. Thus, the drain step 5 lasts for an interval of 15 seconds, obtained by actuating sections R-4 (10 seconds) and R-5 (5 seconds). Programmer 60 actuates switches a through g in a predetermined sequence to control operation of valves A through G.

With particular reference to FIG. 4, it is seen that when the short wash cycle is selected, steps numbers 1-3 and 14-23 are selected by programmer 60. Step 1, ink drain, lasts for an interval of 80 seconds, during which scraper doctor blade 15 engages rotating inking cylinder 11, pump 45 operates at high speed, ink drain valve B is open, and ink roll supply valve C is open. Thus, ink drains from reservoir 22 into bucket 51 and fountain 14 and ink drains from fountain 14 into pan 18 and through return line 44 to the intake side of pump 45. For step 2, lasting for a 5 second interval during which time section R-5 is actuated, solenoid operated valves A, E, F, and G are open. Thus, fresh water passes through open valves F and G and is distributed through the nozzles of spray pipes 23, 24, and thereafter drains into pan 18 and through line 44 to pump 45 which pumps water through line 47 into reservoir 22, with the excess being pumped through drain line 48.

In the 5 second interval of step 3, timer section R-5 is actuated together with valves B and C, so that the action described in connection with step 1 is repeated, except that dirty water rather than ink is being drained. For steps 14-21, the water and drain steps previously described are repeated except that for steps 17-21 doctor blade 15 is retracted from cylinder 11.

For the drain steps 22 and 23, pump 45 ceases operation and doctor blade 15 continues to be spaced from cylinder 11. In addition, the residual water drain valve D is open so that water draining from pan 11 through line 44 does not reach the inlet of pump 45. During step 22 ink return valve A is also open.

Thus, when inks of similar darkness are being changed or when the preceding ink is very much lighter in color than the subsequent ink, within a period of approximately 6 minutes, the inking system is automatically cleaned.

When use of a light color ink is to follow use of a very dark color ink, the long wash cycle is utilized. During step 8 of this cycle, detergent bearing water is circulated by having detergent valve F closed and water valve G opened.

Thus, it is seen that the instant invention provides a novel wash-up system for automatically cleaning inking apparatus. As should now be obvious to one skilled in the art, this wash-up system may also be used for apparatus that produces other types of wetted films.

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now become apparent to those skilled in the art. Therefore, this invention is to be limited not by the specific disclosure herein, but only by the appending claims.

Claims

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. The combination comprising apparatus for producing and transferring a controlled film of liquid, and a wash-up means for cleaning portions of said apparatus; said apparatus including an elongated rotatable cylinder having an outer cylindrical surface on which said controlled film is formed, an elongated doctor means adjacent said cylinder, a fountain at least partially formed between and through the cooperation of said cylinder and said doctor means, a reservoir for storing a supply of said liquid, and conduit means connected between said reservoir and said fountain to direct said liquid from the latter to the former; said wash-up means being constructed so that throughout a wash-up cycle all elements of said wash-up means are spaced from said cylindrical surface; said wash-up means including a catcher trough positioned below said fountain to catch excess liquid and other material flowing therefrom, first and second nozzle bearing means extending lengthwise of said apparatus for directing cleansing and flushing fluids against said apparatus; nozzles of said first nozzle bearing means directing fluid into said fountain; and nozzles of said second nozzle bearing means directing fluid into the nip region between said doctor means and said cylinder from a position below said nip region.

2. The combination as set forth in claim 1 in which there are first and second inlets for cleansing and flushing fluids, respectively; power operated control valves for selectively connecting said inlets to said nozzle bearing means; and programmer means operatively connected to said control valves to control operation thereof in a predetermined sequence established for cleaning said apparatus.

3. The combination as set forth in claim 2 in which there is a return line between said catcher trough and said reservoir; and pump means in said return line for selective pumping of liquids and other fluids into said reservoir under the control of said programmer.

4. The combination as set forth in claim 3 in which there is a means operable to engage said doctor means and said cylinder for intervals of a wash-up cycle during which cleansing and flushing fluids are flowing from said nozzle bearing means.

5. The combination as set forth in claim 3 in which the pump means has an inlet and an outlet; said inlet being on the trough side of said pump means and said outlet being on the reservoir side of said pump means.

6. The combination as set forth in claim 5 in which there is a drain means connected to said return line on the outlet side of said pump means.

7. The combination as set forth in claim 6 in which there is another power operated control valve between the return line and drain means; said another control valve being closed when said pump means is operating, during recirculating intervals of a wash-up cycle controlled by said programmer, to transfer cleansing and flushing fluids from said trough to said reservoir and back to said fountain through said conduit means.

8. The combination as set forth in claim 7 in which there is a means operable to engage said doctor means and said cylinder for intervals of a wash-up cycle during which cleansing and flushing fluids are flowing from said nozzle bearing means.

9. The combination as set forth in claim 1 in which the doctor means comprises a scraper blade arranged so that an acute angle is formed between the scraper blade and the tangent drawn from the line of contact between said blade and said cylinder and extending from said line in the direction of cylinder rotation.

10. The combination as set forth in claim 9 in which the second nozzle bearing means includes some nozzles directing fluid against the underside of said blade.

11. The combination as set forth in claim 10 in which the second nozzle bearing means includes other nozzles for directing fluid against the cylinder at a region below the line of contact.