Varnish coating apparatus

Coating apparatus – With printing

Reexamination Certificate

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Details

C118S212000, C118S227000, C118S236000, C118S244000, C118S249000, C118S255000, C118S262000, C101S229000, C101S231000

Reexamination Certificate

active

06772709

ABSTRACT:

BACKGROUND OF INVENTION
The present invention relates to a varnish coating apparatus for coating a sheet-like matter with varnish to prevent stains on a printed sheet-like matter or obtain a better appearance of it and, more particularly, to a varnish coating apparatus for coating both surfaces of a sheet-like matter with varnish in a single path.
Japanese Patent Laid-Open No. 10-296953 (reference 1) discloses a coating apparatus which coats both surfaces (obverse and reverse surfaces) of a sheet-like matter with varnish in a single path without inverting the sheet-like matter. A coating unit
80
disclosed in reference 1 is arranged downstream in the paper convey direction of a printing section (not shown). The coating unit
80
has a blanket impression cylinder
82
in contact with a transfer cylinder
81
of the printing section, and first and second varnish coating units
83
and
84
, as shown in FIG.
8
.
The first varnish coating unit
83
is arranged upstream in the paper convey direction from the contact point between the blanket impression cylinder
82
and the transfer cylinder
81
. The first varnish coating unit
83
is constituted by a varnish pan
86
a
which stores varnish, a fountain roller
87
a
dipped in varnish in the varnish pan
86
a
, a metering roller
88
a
in contact with the fountain roller
87
a
, a form roller
89
a
in contact with the metering roller
88
a
, and a coater cylinder
85
a
in contact with the form roller
89
a
and opposing a paper sheet held by the transfer cylinder
81
.
In this arrangement, varnish in the varnish pan
86
a
is transferred to the coater cylinder
85
a
through the fountain roller
87
a
, metering roller
88
a
, and form roller
89
a
and then to the peripheral surface of the blanket impression cylinder
82
through the coater cylinder
85
a
. The first varnish coating unit
83
which is arranged upstream in the paper convey direction from the contact point between the blanket impression cylinder
82
and the transfer cylinder
81
transfers varnish to the peripheral surface of the blanket cylinder
82
before it receives the paper sheet from the transfer cylinder
81
. Accordingly, when the paper sheet transferred from the transfer cylinder
81
to the blanket impression cylinder
82
passes through the contact point between the blanket impression cylinder
82
and a coater cylinder
85
b
of the second varnish coating unit
84
, varnish transferred to the peripheral surface of the blanket impression cylinder
82
is transferred to the reverse surface of the paper sheet by the printing pressure of the coater cylinder
85
b
so that the reverse surface is coated with varnish.
The second varnish coating unit
84
is arranged downstream in the paper convey direction from the contact point between the blanket impression cylinder
82
and the transfer cylinder
81
. Like the above-described first varnish coating unit
83
, the second varnish coating unit
84
is constituted by a varnish pan
86
b
, a fountain roller
87
b
, a metering roller
88
b
, a form roller
89
b
, and the coater cylinder
85
b
. In this arrangement, varnish in the varnish pan
86
b
is transferred to the coater cylinder
85
b
through the fountain roller
87
b
, metering roller
88
b
, and form roller
89
b
. When the paper sheet passes through the contact point between the blanket impression cylinder
82
and the coater cylinder
85
b
, varnish on the coater cylinder
85
b
is transferred to the obverse surface of the paper sheet so that the obverse surface is coated with varnish.
After coating, the paper sheet is gripped from the transfer cylinder
81
by the blanket impression cylinder
82
. The paper sheet whose obverse and reverse surfaces are coated with varnish is gripped by delivery grippers (not shown) of a delivery chain
91
. The gripped paper sheet is conveyed by the delivery chain
91
. The applied varnish is dried by drying units
92
,
93
, and
94
during conveyance. Then, the paper sheet is dropped onto a delivery pile (not shown) and stacked.
In the conventional coating apparatus, when pattern coating or partial coating is necessary for the obverse surface of a paper sheet, a printing plate having a projecting portion is attached in correspondence with a patterned coating portion in place of the blanket attached on the peripheral surface of the coater cylinder
85
b
of the second varnish coating unit
84
.
However, as shown in
FIG. 9
, if double-side coating is to be performed in which a pattern coating region
9
B on the reverse surface of a paper sheet
9
does not overlap a pattern coating region
9
A of the obverse surface of the paper sheet
9
, the pattern coating region
9
B on the reverse surface is pressed by the recessed portion of the printing plate, and therefore, no sufficient printing pressure is applied to the coating region
9
B on the reverse surface. In addition, when full coating is to be performed on the reverse surface, no sufficient printing pressure is applied to the reverse surface region that does not correspond to the pattern coating region on the obverse surface. For this reason, the conventional coating apparatus cannot perform pattern coating on the reverse surface of a paper sheet when the obverse surface of the paper sheet is to be pattern-coated.
To solve this problem, a coating apparatus disclosed in Japanese Patent Laid-Open No. 2000-103035 (reference 2) is proposed. The coating apparatus disclosed in reference 2 has a first coating unit which coats the obverse surface of a paper sheet on the peripheral surface of an odd-numbered cylinder (to be referred to as an odd-number cylinder hereinafter) located from the upstream side to the downstream side in the paper convey direction, a second coating unit which coats the reverse surface of the paper sheet on the peripheral surface of an even-numbered cylinder (to be referred to as an even-number cylinder hereinafter), and a drying unit arranged downstream of each coating unit.
In this arrangement, the obverse surface of a paper sheet is coated by the first coating unit on the peripheral surface of an odd-number cylinder. After that, the varnish applied to the obverse surface is dried by the drying unit. Subsequently, the reverse surface of the paper sheet is coated by the second coating unit on the peripheral surface of an even-number cylinder. After that, the varnish applied to the reverse surface is dried by the drying unit. In this way, the obverse and reverse surfaces of a paper sheet are coated selectively on the odd-and even-number cylinders, thereby making pattern coating on both the obverse and reverse surfaces of a paper sheet.
In the above-described coating apparatus, however, since the obverse and reverse surfaces of a paper sheet are selectively coated on the odd- and even-number cylinders, a cylinder dedicated to obverse surface coating and that dedicated to reverse surface coating are necessary. This increases the manufacturing cost and also increase the total length of the machine. In addition, in winding a paper sheet around the cylinder dedicated to reverse surface coating after obverse surface coating, a drying unit is required to prevent varnish on the obverse surface of a paper sheet from sticking to the cylinder dedicated to reverse surface coating. In this case, the varnish must be dried in a short time. To do this, a bulky drying unit is necessary, resulting in an increase in manufacturing cost.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a coating apparatus capable of reliably executing double-side coating including pattern coating on the reverse surface of a sheet-like matter.
It is another object of the present invention to provide a varnish coating apparatus which reduces the size and manufacturing cost.
In order to achieve the above objects, according to the present invention, there is provided a varnish coating apparatus comprising a first varnish film forming cylinder having a first supply surface to which varnish is supplied, a second varnish film forming cylinder having a second su

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