Patent Application
20050081729
The present invention relates to an ink applicator. More particularly this invention concerns a device which applies a coating of ink or a similar liquid to a ink-transfer roller.
A standard ink applicator for a printing machine or the like has an ink applicator that normally sits atop a transfer roll. The applicator forms a thin uniform coat of ink on the transfer roll which is then applied to the actual printing roll.
Such an applicator typically includes a pair of end parts that are spaced longitudinally apart and a pair of bars extending longitudinally parallel to each other between the end parts and each carrying a flexible applicator blade. The end parts, bars, and blades form a compartment that is open downward through a gap defined between confronting but spaced free edges of the blades. In use these blades ride lightly on the surface of the transfer roll and so that ink in the compartment can flow onto the transfer roll, being doctored into a thin layer by the trailing blade.
While such an arrangement works very well, when the applicator has to be changed, for instance because it needs servicing or different ink or tint is to be applied, it is standard practice to run the applicator dry. Once it is empty, it can be lifted off the transfer roll and switch for a new one that is then filled and used.
If the applicator is lifted off the transfer roll while still full there is usually a mess. Even though the ink is typically quite viscous, it can still flow out the bottom of the applicator, normally fouling the machine. This procedure is not normally preferred; instead it is better to shut off the ink supply and run the printer, thereby wasting ink and paper, until the applicator is empty.
It is therefore an object of the present invention to provide an improved ink applicator.
Another object is the provision of such an improved ink applicator which overcomes the above-given disadvantages, that is which can be easily switched, even when full, without making a mess or losing any significant quantity of ink.
An ink applicator has according to the invention at least one generally stationary mounting part, a fixed elongated bar fixedly mounted on the mounting part and carrying an elongated applicator blade, and a movable elongated bar mounted on the mounting part, extending parallel to the fixed bar, carrying an elongated applicator blade parallel to the fixed-bar blade, and defining an elongated ink-holding compartment with the fixed bar. The movable bar is supported on the mounting part for movement between an outer position with the movable-bar blade spaced transversely from the fixed-bar blade and defining a gap through which ink can flow out of the compartment and an inner position with the blades engaging one another and closing the gap so that no ink can flow out of the compartment.
Thus it is possible to close the gap in the ink applicator before it is lifted off the transfer roller. This makes it possible to switch out the ink applicator at virtually any time, even when full, without wasting ink or paper. What is more, the reverse process of putting a closed but full applicator into the press and then opening its gap while the blades are in contact with the transfer roll is also extremely efficient. No longer are there unneeded print runs for depleting ink or getting the ink started.
The movement of the movable bar can be a translatory movement or a pivotal movement. Normally according to the invention guide formations constrain the movable bar and its blade to translatory movement transversely relative to the fixed bar between its inner and outer positions. The translatory movement is preferably along an arc corresponding to the radius of curvature of the transfer roll so that the movable-bar blade edge remains in light but sealing contact with the transfer-roll surface during closing (and opening). When the movable bar is pivotal, its pivot axis is offset from the free edge of the movable-bar blade so that this edge moves along an arc during the pivoting. In fact both bars could be pivoted to move together and apart. In any case mechanism is provided to keep the blade edges in contact with the transfer-roll surface as the applicator is being moved from the open to the closed position.
The guide formations include an axially projecting pin and a transversely elongated slot in which the pin can slide. The slot is formed in the end part and the pin is fixed in the m movable bar. More particularly, normally there are two such end parts at longitudinally opposite ends of the fixed bar and each of the end parts is formed with one such slot and the movable bar is provided with two such pins riding in the slots. In fact two or more such pins riding in respective slots can be provided on each end of the movable bar to ensure perfectly controlled translatory movement.
The ink applicator according to the invention is further provided with a seal engaging both blades at the end part and preventing leakage from the compartment out the gap adjacent the end part in both positions of the movable bar. This seal has a lip bearing on back faces of both blades.
The ink applicator further comprises a latch for locking the movable bar releasably in each of its positions. This latch includes a longitudinally retractile pin and a stop plate having a pair of holes in each of which the pin is engageable in a respective one of the positions of the movable bar. The latch pin is on the movable bar and the stop plate is on the end part. Similarly, there are two such end parts at longitudinally opposite ends of the fixed bar and each of the end parts is provided with one such stop plate and the movable bar is provided with two such pins.
The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:
As seen in
According to the invention as mentioned above, the bar 3 and its blade 6 are fixed to the end parts 2. The bar 4, however, is provided at its ends with pins 17 that ride in respective slightly arcuate transverse grooves 11 in the end parts 11. Thus the bar 4 and its blade 5 can move transversely toward and away from the bar 3 and blade 6 as will be described below. In addition a latch assembly 12 on each end of the bar 4 has a longitudinally spring-loaded and displaceable pin 13 that can fit in either of two holes 15′ and 15″ of a stop plate 14 fixed on the respective end part 2. When the pins 13 are engaged in the outer holes 15′ (to the right in
During normal use, when the end parts 2 are fitted to a machine having the transfer roll 18, the pins 13 are engaged in the outer holes 15′ so that the gap 8 is open and ink or the like can move from the compartment 7 through the gap 8 onto the surface of the transfer roller 18. For a change in ink, the machine operator retracts the pins 13 and presses the bar 4 transversely toward the bar 3. The pins 11 slide along the grooves 11, which have the same radius of curvature as the outer surface of the roller 18 so that the edge of the blade 5 will rest is light contact with it during this movement. The edge of the blade 5 will come to rest on the upper or back face of the blade 6 about when the pins 13 snap back out to engage in the holes 15″, at which time the gap 8 is effectively closed and the entire applicator 1 can be lifted off the roller 18 and replaced with another. Engagement of the pins 13 in the holes 15″ holds the applicator 1 closed. The ink in the compartment 7 can shift into the pocket 16 so that, even if the applicator gap 8 is closed when the compartment is relatively full, ink will not be forced back up and out the top of the applicator 1. Both bars 3 and 4 can be formed with such pockets 16.
It is of course within the scope of the invention to provide a motor or other actuator, e.g. a small pneumatic cylinder, to shift the movable blade bar 4 transversely between its end positions. Furthermore it would be possible for the movable bar 4 to move by pivoting, rather than the described translatory movement.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10342519.5 | Sep 2003 | DE | national |
| 10349053.1 | Oct 2003 | DE | national |
