Coating apparatus – Control means responsive to a randomly occurring sensed... – Responsive to attribute – absence or presence of work
Reexamination Certificate
2002-11-18
2004-12-07
Edwards, Laura (Department: 1734)
Coating apparatus
Control means responsive to a randomly occurring sensed...
Responsive to attribute, absence or presence of work
C118S103000, C118S211000, C118S212000, C118S261000
Reexamination Certificate
active
06827783
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a paste application apparatus which applies a paste, for example, an adhesive, conductive adhesive, external electrode, or flux, to a target for coating, for example, an electronic component, and a method for applying a paste.
2. Description of the Related Art
An example of the aforementioned type of paste application apparatus is disclosed in Japanese Unexamined Patent Application Publication No. 10-41339. As shown in
FIG. 8
, this is provided with a coating applicator (roller)
2
for circulating and moving a paste
3
in a constant direction in order that the circumferential velocity V
2
at the coating area A becomes a constant, a storage portion
1
for storing the paste
3
and bringing this paste into contact with the coating applicator
2
, a squeegee
4
for adjusting the liquid thickness of the paste on the coating applicator in order that the thickness, that is, layer thickness, of the paste on the coating applicator
2
becomes constant in the coating area A, and a head
5
for moving the target for coating in the horizontal direction to a position
11
, in order that when the target for coating
6
crosses the coating area A, the movement velocity V
1
of the target for coating and the circumferential velocity V
2
become in agreement with each other.
Another apparatus of this type is disclosed in Japanese Patent No. 3131156 (Japanese Unexamined Patent Application Publication No. 6-296929). Regarding this apparatus, as shown in
FIG. 9
, a predetermined quantity of paste
3
is adhered to the perimeter of a rotating thin disk-shaped coating disk
7
, the paste adhered to the perimeter of the aforementioned coating disk
7
is transferred to the side surface of the chip-shaped components c while the chip-shaped components c as targets for coating are moved linearly in the tangential direction of the aforementioned disk
7
and, in addition, the shape of the paste e applied to each chip-shaped component c can be appropriately changed by controlling the difference between the circumferential velocity V
2
of the perimeter of the aforementioned coating disk
7
and the movement velocity V
1
of the chip-shaped component c during this transfer.
Another known paste application apparatus is shown in
FIGS. 24A and 24B
. A coating roller
103
having a width corresponding to the coating width is immersed in a paste bath
101
storing a paste
102
and is rotated so as to form a paste layer
102
a
having a predetermined thickness on the perimeter of the coating roller
103
, and a target for coating
106
is brought into contact with this paste layer
102
a
so as to transfer and apply the paste. Specifically, a paste application apparatus for applying the paste to one surface of the target for coating, for example, an electronic component, is disclosed in Japanese Unexamined Patent Application Publication No. 10-41339.
This paste application apparatus is provided with a roller which is supplied with the paste to the perimeter surface and which rotates in one direction, and a transport mechanism which transports the target for coating in the condition that one surface thereof faces toward the perimeter surface of the roller to a required position above this roller, and the paste is applied to the one surface of the target for coating via the roller. In this paste application apparatus, the coating thickness of the paste with respect to one surface of the target for coating is determined by the adherence thickness of the paste with respect to the perimeter surface of the roller.
Furthermore, in this paste application apparatus, the paste is supplied to the perimeter surface of the roller rotating in one direction. The target for coating is transported to the required position above the roller in the condition that one surface thereof faces toward the perimeter surface of the roller. According to this, the paste is applied to the target for coating via the roller.
Specifically, this paste application apparatus is as shown at
411
in
FIG. 53
, and is provided with a cylindrical roller
412
, a paste storage portion
419
for storing the paste, a movement mechanism
416
for moving the targets for coating
417
in order to bring them into contact with the paste layer
414
on the roller, and a squeegee
415
for adjusting the paste adhered to the perimeter of the roller
412
to have a constant film thickness.
In this paste application apparatus
411
, when the roller
412
is rotated, the paste stored in the paste storage portion
419
is adhered to the perimeter of the roller
412
. The paste adhered to the perimeter of the roller is adjusted to have a predetermined thickness by the squeegee
415
and, therefore, the paste layer
414
is produced. On the other hand, the movement mechanism
416
is for horizontally moving the adsorbed target for coating
417
above the roller
412
at the height at which the target for coating
417
is partially immersed in the paste layer
414
and, therefore, the paste is applied to the target for coating
417
when the bottom surface of the target for coating
417
passes through the paste layer.
Other conventional paste application apparatus is disclosed in Japanese Unexamined Patent Application Publication No. 8-19752. In this paste application apparatus, a paste is applied to the target for coating via a horizontal disk-shaped base. The paste is supplied along an arc-shaped path on the base with a predetermined thickness. The target for coating is pressed against the paste on the base.
The paste applied as described above is applied to the top surface portion or bottom surface portion, and the front portion and rear portion in the chip type electronic component, and it is desirable that the front portion and the rear portion are coated evenly. That is, for example, when the paste is a conductive adhesive, in mounting the electronic component, which is the target for coating after being coated, on a circuit substrate, occurrence of failure in mounting can be reduced by evenly joining the front and rear portion of the electrode of the component to the wiring of the substrate.
Among the aforementioned conventional techniques, regarding the former application apparatus, the coating applicator, for example, a roller, has an arc-shaped perimeter surface. When the paste is applied to the target for coating by horizontal movement of the head during movement of the paste layer together with the rotation of the roller, the target for coating has components of movement in both of the vertical and horizontal directions relative to the paste surface in the coating area (in the paste). Then, the target for coating scrapes the paste by the quantity of movement in the horizontal direction among them. Even when the paste layer surface of the coating applicator moves at a velocity equivalent to the movement velocity of the target for coating, difference in this component of movement in the horizontal direction (quantity of horizontal movement) occurs between the front portion and the rear portion of the target for coating. Consequently, difference in the quantity of scraping of the paste occurs between the front portion and the rear portion of the target for coating due to this difference in the quantity of horizontal movement and, therefore, difference in the quantity of coating occurs.
The reason for this will be described with reference to FIG.
5
. This
FIG. 5
shows orthogonal coordinates of the coordinate system viewed from the side with respect to the movement direction of the target for coating centering the hypothetical reference point O that is an arbitrary point on the paste layer surface moving together with the rotation of the roller. Here, the horizontal axis is the tangent to the paste layer surface at the point of contact of the hypothetical reference point O, and the vertical axis is the direction perpendicular to the tangent (the direction of the normal to the paste layer surface) passing through the hypothetical reference point O. Regarding the
Mori Tetsuya
Okeshi Motoyuki
Edwards Laura
Murata Manufacturing Co. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
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