Printing – Inkers – Roller
Reexamination Certificate
1999-10-07
2001-09-25
Asher, Kimberly L. (Department: 2854)
Printing
Inkers
Roller
C101S366000
Reexamination Certificate
active
06293195
ABSTRACT:
BACKGROUND OF THE INVENTION
Chambered flexographic (“flexo”) ink units, employ two opposing, blades—a doctor blade and a sealer or containment blade—together with elastomeric end seals to form an enclosed chamber which contains ink being applied to a metering, (“anilox”) roll. These two types of blades will hereafter be referred to collectively as “roll blades”. A simplified yet typical flexographic printing system is depicted in FIG.
1
and is indicated generally at
10
. A conventional, chambered flexographic ink unit or “inker”
12
adjoins and applies ink to a metering or anilox roll
14
of the system
10
. The anilox roll
14
in turn applies its ink to the image carrier
16
, typically a “flexo plate cylinder”. Cylinder
16
in turn applies its ink to a flexible web
18
typically carried on a central drum
20
rolling against the flexo plate cylinder
16
. Ink unit
12
is one of several such units which would be arrayed around the central drum.
As is further indicated in
FIG. 2
, the ink unit or “inker”
12
includes a body
30
, which may be C-shaped in transverse cross section as indicated or of another shape. A recessed chamber
32
is formed into one side of the body facing the anilox roll
14
to receive ink to be printed on the web. A doctor blade
34
is typically clamped to the downstream edge of the holder body
30
by means of screws
38
and a clamping bar
40
. A sealer or containment blade
36
is clamped to the upstream edge of the body
30
(see FIG.
1
). There is typically one screw
38
every three to five inches of clamping bar
40
on ink units over twenty-two inches in length, (so-called “wide web” equipment) and one screw approximately every inch on ink units under twenty-two inches (so-called “narrow web” equipment). In this clamping configuration, the blades
34
,
36
may be aligned to the holder body
30
by means of alignment pins
42
or, in some cases, machined “steps” (not depicted) in the holder body, which engage the back of the blades
34
,
36
in a manner similar to the pins
42
. Elastic seals
44
(e.g., “O-ring” strips) are provided between the blades
34
,
36
and the body
30
to seal the blades with the body.
Doctor blades are typically installed nearly edge (i.e. nearly perpendicular to) on the anilox roll and are subject to significant pressure and wear. For that reason, they are made of steel, typically stainless steel or tool steel or steel otherwise treated to resist wear. Containment blades are generally installed at much shallower angles closer to tangent and are subject to significantly less pressure and wear than doctor blades. For that reason, containment blades are made from non-steel materials and can be made from non-metallic materials such as plastic.
A number of costs and operational problems exist with the existing means of clamping doctor and sealer or containment blades with screws. These are:
(A) Distortion of the clamp bar by non-uniform screw tightening. Uniform torquing of each screw with hand tools is difficult, time consuming and easily frustrated by varying degrees of individual screw-thread ink contamination, wear, damage and corrosion. This is a major cause of waviness, distortion or “ripples” in the clamped blade, resulting in doctoring and print defects and/or shortened blade life, as well as ink leakage paths under wavy, distorted or rippled doctor blades.
(B) Increased costs and/or extended press make-ready time resulting from operators working to prevent or correct holder screw problems described in (A).
(C) Difficult access to the inside of the “jaws” which hold the doctor and containment blades. Fast, easy and complete access to these surfaces is needed to remove dried ink which may be present, inspect jaw surfaces for scratches and other damage and/or replace blade ink seals if they are the type that require access, such as the O-ring strip seal
44
illustrated in FIG.
2
. Removing ten or more holder screws to gain this access is very slow.
BRIEF SUMMARY OF THE INVENTION
The invention is a flexographic printer ink unit comprising: an elongated body having an elongated ink chamber recessed into one side of the body, the chamber being defined in part by one elongated wall of the body; an elongated roll blade on the one elongated wall; an elongated clamping bar coupled with the body to rotate about one pivot, one longitudinal edge of the clamping bar holding the roll blade against a proximal edge of the elongated wall such that the roll blade forms an edge of the ink chamber; and a plunger movably coupled with the body and pressed against the clamping bar on a side of the first pivot axis opposite the one longitudinal edge so as to pivot the one longitudinal edge of the clamping bar against the proximal edge of the wall to secure the roll blade there between.
REFERENCES:
patent: 3783781 (1974-01-01), Grommek
patent: 5406887 (1995-04-01), Hertel et al.
patent: 6089159 (2000-07-01), Gorter
Akin Gump Strauss Hauer & Feld L.L.P.
Alhsontech Sales Incorporated
Asher Kimberly L.
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