JPH07312306A - Terminal electrode film applicator for chip resistors - Google Patents

Abstract

PURPOSE:To avoid the cracking or breaking of a rod-like base board piece by rotatably disposing an intermediate rollers distant from applying rollers and feed rollers and placing clamps so that this piece is reciprocatingly movable between an advance and retract positions with respect to the applying rollers. CONSTITUTION:A conductive paste 4 in tanks 5a and 5b is pumped up by the intermittent rotation of feed rollers 6a and 6b so as to deposit like a film to the outside faces of these rollers. The paste on these faces of the rollers is transferred to those of intermediate rollers 3a and 3b disposed distantly from the rollers 6a and 6b such that it is widely expanded in the axial direction uniformly to form films of specified thickness on the outside faces of the rollers 3a and 3b and length side edges A3' and A3'' of a rod-like base board piece A3 are put close to them by the advance of clamps 1 to apply the paste 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to form terminal electrode films on both left and right end surfaces of a chip type insulating substrate by coating terminal electrodes on both ends of a resistive film on the upper surface of the insulating substrate when manufacturing a chip resistor. It relates to the device.

[0002]

2. Description of the Related Art Generally, a chip resistor has a terminal electrode film formed by the following procedure. First, as shown in FIG. 1, a plurality of vertical streak lines A1 and horizontal streak lines A2 are engraved in a grid pattern on the surface of a ceramic material substrate A, while a resistive film ( After the formation (not shown), the material substrate A is broken into rod-shaped substrate pieces A3 along the respective longitudinal streak lines A1. Next, the left and right long side edges A3 ', A of the rod-shaped substrate piece A3
3 ″ is coated with a conductive paste to be a terminal electrode film. As a coating device for this conductive paste, as shown in FIGS. 6 and 7, a coating roller 21 which is intermittently rotated by a motor drive, A tank 22 adjacent to the coating roller 21 is used, and a cutout groove 23 having a predetermined depth extending in the axial direction of the coating roller 21 is formed on the outer peripheral surface of the coating roller 21 at regular intervals. The conductive paste 24 in the tank 22 attached to the outer peripheral surface of the coating roller 21 as the coating roller 21 rotates.
Is the scraper 2 that is in contact with the outer peripheral surface of the application roller 21.
5 is removed into the tank 22 and the cutout groove 2
3, the longitudinal side edge surfaces A3 ′, A3 ″ of the rod-shaped substrate piece A3 are pushed into the notch groove 23 filled with the conductive paste 24 when the rotation of the coating roller 21 is stopped. Thus, the conductive paste 24a is applied to the longitudinal side edge surfaces A3 'and A3 "of the rod-shaped substrate piece A3. Then, the conductive paste 2 on the rod-shaped substrate piece A3
By firing 4a, the terminal electrode film is formed.

The chip resistor in which the terminal electrode film is formed by the above-mentioned method tends to become smaller in size in recent years, and the film thickness of the terminal electrode film becomes smaller accordingly. As shown in FIG.
It is necessary to make the application dimension W ′ of the conductive paste 24a on the longer side edge surfaces A3 ′, A3 ″ of 3 smaller.

[0004]

However, by removing the conductive paste 24 adhering to the outer peripheral surface of the coating roller 21 by the scraper 25 as in the conventional case, the conductive paste 24 is left only in the notch groove 23. In the filling method, in most cases, even a part of the conductive paste 24 in the cutout groove 23 is removed when it is removed by the scraper 25, and the filling amount of the conductive paste 24 in the cutout groove 23 is stabilized. It is difficult to do so, and the filling amount of the conductive paste 24 tends to vary,
When the rod-shaped substrate piece A is pushed into the notch groove 2, the amount of the conductive paste 24 applied to the rod-shaped substrate piece A3 is not constant, and the application dimension W'of the rod-shaped substrate piece A is applied in a small and stable state. It was very difficult to do.

Moreover, when the coating size W'is small,
When the chip resistor is soldered and mounted on a printed circuit board or the like, a soldering defect is likely to occur, and when the coating dimension W ′ is large, when the chip resistor is soldered and mounted on the printed circuit board or the like. However, there is a problem that a solder bridge is formed between adjacent components on the printed circuit board.

Further, with respect to a network resistor in which two or more chip resistors are connected to each other, the terminal electrode films of the adjacent chip resistors come into contact with each other to cause an electrical short circuit. It was happening. In order to solve such a problem, Japanese Patent Application No. 5-9331 has been conventionally used.
No. 4 publication and as shown in FIG. 9, the delivery roller 33 immersed in the conductive paste 32 in the tank 31 and rotated in the same direction as the delivery roller 33 while being in contact with the delivery roller 33. There has been proposed a coating method using an apparatus including an intermediate roller 34 and a coating roller 35 which is in contact with the intermediate roller 34 and rotates in the same direction as the intermediate roller 34. According to this method, the conductive paste 32 is pumped up from the tank 31 so as to adhere to the outer peripheral surface of the feeding roller 33 in a film shape, and then transferred onto the outer peripheral surface of the intermediate roller 34, and further, the outer peripheral surface of the coating roller 35. Is formed to have a substantially uniform thickness over the entire axial direction, and the rod-shaped substrate is pressed against the outer peripheral surface of the coating roller 35 while the long side edges of the rod-shaped substrate piece A3 are in contact with each other. The conductive paste 32 is applied to the long side edge of the piece A3.

However, in such a method, the conductive paste 32 is rotated while being transferred while the outer peripheral surfaces of the feeding roller 33 and the coating roller 35 are in contact with the outer peripheral surface of the intermediate roller 34. Coating roller 35
The thickness of the conductive paste 32 formed on the outer peripheral surface of the conductive paste 32 becomes extremely thin, and the conductive paste 32 cannot be stably applied unless the applying roller 34 is directly brought into contact with the longitudinal side edge of the rod-shaped substrate piece A3. Therefore, at the time of contact between the coating roller 34 and the long side edge of the rod-shaped substrate piece A3, defects such as chipping and cracks are likely to occur at the long side edge of the rod-shaped substrate piece A3, which has not been put to practical use.

The present invention has been devised under the above circumstances. When the terminal electrode film of a chip resistor is formed, the rod-shaped substrate piece is not cracked or chipped, and the rod-shaped substrate piece is not formed. It is an object of the present invention to provide a device for coating a terminal electrode film in a chip resistor, which can make the coating size of the conductive paste substantially uniform.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention immerses a coating roller of intermittent rotation type whose axis is substantially horizontal and a lower portion thereof into a conductive paste in a conductive paste tank. At least one intermediate roller is rotatably disposed between the intermittent rotation type delivery roller and the application roller and the delivery roller while being separated from both the application roller and the delivery roller. A clamper for the rod-shaped substrate piece arranged parallel to the axis of the coating roller, and a forward position where the rod-shaped substrate piece approaches the coating roller when the coating roller stops rotating, and a retracted position from the coating roller. The present invention provides a coating device for a terminal electrode film in a chip resistor, which is provided so as to reciprocate between them.

Further, according to the present invention, in the above chip resistor, the separation distance between the intermediate roller and the coating roller and the feeding roller is 0.02 mm to 0.05 mm, respectively. A coating device for a terminal electrode film is provided.

[0011]

In this structure, the conductive paste in the conductive paste tank is pumped up by the intermittent rotation of the feeding roller so as to adhere to the outer peripheral surface of the feeding roller in a film shape, and then the feeding paste of the feeding roller is rotated. The conductive paste on the outer peripheral surface, when transferred to the outer peripheral surface of the intermediate roller arranged apart from the feeding roller, is widely spread to a predetermined thickness in the axial direction on the outer peripheral surface of the intermediate roller, and From the outer peripheral surface of the intermediate roller to the outer peripheral surface of the coating roller, the coating roller is stably formed to have a predetermined thickness substantially uniformly over the entire axial direction of the coating roller.
Thus, the longitudinal side edge of the rod-shaped substrate piece is brought closer to the outer peripheral surface of the coating roller on which the conductive paste having the predetermined thickness is formed by the forward movement of the clamper, so that the longitudinal side of the rod-shaped substrate piece. Apply conductive paste to the edges.

In this case, the longitudinal side edge of the rod-shaped substrate piece is not contacted with the outer peripheral surface of the coating roller and is immersed in the conductive paste formed to have a substantially uniform thickness. It is possible to apply a stable amount of the conductive paste without causing defects such as chipping. The distance between the intermediate roller and the feeding roller and the coating roller is 0.02 mm to 0.
When the thickness is about 05 mm, the conductive paste can be formed with a constant thickness on the outer peripheral surface of each roller, so that the conductive paste can be applied in a stable state on the long side edge of the rod-shaped substrate piece.

Therefore, according to the present invention, when the terminal electrode film of the chip resistor (particularly a small chip resistor) is formed, the conductive paste for the rod-shaped substrate piece can be formed without cracking or chipping of the rod-shaped substrate piece. The coating dimensions can be made approximately the same, and even if the chip resistor is mounted on a printed circuit board, it is possible to reliably reduce the occurrence of soldering defects and solder bridges on the printed circuit board, and the chip In the network resistor in which two or more resistors are connected, there is an effect that adjacent side surface terminal electrodes do not come into contact with each other.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 5, but the present invention is not limited to this. As described above and as shown in FIG. 1, the chip resistor has the terminal electrode film formed by the following procedure.

First, on the surface of the ceramic material substrate A,
A plurality of vertical streak lines A1 and horizontal streak line A2 are engraved in a grid pattern, and a resistance film (not shown) is formed on the surface of the material substrate A.
After forming, the material substrate A is broken into rod-shaped substrate pieces A3 along the respective longitudinal lines A1. Next, the left and right long side edges A3 ', A of the rod-shaped substrate piece A3
3 ″ is coated with a conductive paste which will be a terminal electrode film.
An apparatus as shown in FIGS. 2 and 3 is used for applying the conductive paste.

This coating apparatus comprises a clamper 1 made of an epoxy resin for clamping both ends of the rod-shaped substrate piece A3, and left and right side portions of the rod-shaped substrate piece A3 clamped by the clamper 1 in the short side direction. Two columnar coating rollers 2a and 2b made of epoxy resin, whose axes are arranged substantially parallel to the rod-shaped substrate piece A3, and a pair of coating rollers 2a and 2b, which are spaced apart from each other by a predetermined distance. Two columnar intermediate rollers 3a and 3b, and two tanks 5a made of aluminum having a bottom shape, which are arranged at positions separated by a predetermined distance from both the intermediate rollers 3a and 3b, and which store the conductive paste 4. 2 arranged so as to be respectively immersed in the conductive paste 4 in 5b
It is provided with one cylindrical delivery roller 6.

The clamper 1 is provided with a pair of openable and closable clamp pieces 1a and 1b.
The rod-shaped substrate piece A3 is clamped by clamping the rod-shaped substrate piece A3 from its longitudinal direction by the approaching movement of the clamp pieces 1a, 1b to the rod-shaped substrate piece A3 accompanying the expansion and contraction of pneumatic cylinders (not shown) connected and fixed to a and 1b, respectively. Then, the bar-shaped substrate piece A
The clamp is configured to be released by the backward movement from 3. The upper part of the clamper 1 is
A vacuum suction type collet K is provided so as to supply the rod-shaped substrate piece A3 to the clamper 1 or carry it away from the clamper 1.

The coating rollers 2a and 2b are arranged so as to face each other on the left and right with respect to the rod-shaped substrate piece A3 with their axes substantially horizontal. Are arranged substantially horizontally and face each other. Both application rollers 2a, 2b, both intermediate rollers 3
The a, 3b and the two delivery rollers 6a, 6b are driven by a motor drive (not shown) or the like so as to intermittently rotate in the arrow direction. This intermittent rotation is performed by both application rollers 2a,
A reflection type optical sensor S for recognizing a notch formed on one side surface of 2b recognizes the rotational positions of both coating rollers 2a, 2b, thereby temporarily stopping the rotation. ing.

The rotation speed of each roller is set so as to increase in the order of the coating rollers 2a and 2b, the intermediate rollers 3a and 3b, and the feeding rollers 6a and 6b. The tanks 5a and 5b are provided with scrapers 7a and 7b at positions separated from the outer peripheral surfaces of the feeding rollers 6a and 6b. Meanwhile, the intermediate roller 3
The separation distance between a and 3b, and the coating rollers 2a and 2b and the feeding rollers 6a and 6b is about 0.03, respectively.
It is rotatably arranged with a separation distance of mm maintained.
In addition, the scrapers 7a and 7b and the feeding roller 6
The separation distance from a and 6b is also about 0.03 mm.

Further, as shown in FIG. 4, the clamper 1
When the bar-shaped substrate A3 clamped by the clamper 1 is stopped rotating, the advancing position where the bar-shaped substrate A3 approaches without contacting both the application rollers 2a and 2b and the application rollers 2a and 2b. It is configured to reciprocate between and from the retracted position. The approach and retreat of the clamper 1 are performed by the expansion and contraction of a pneumatic cylinder (not shown) connected to the clamper 1 (in FIG. 4, only the coating roller 2a is shown).

Using the coating apparatus having such a structure, the terminal electrode film of the rod-shaped substrate piece A3 is formed as follows. First, the conductive paste 4 in the tanks 5a and 5b
Are pumped by intermittent rotation of the feeding rollers 6a and 6b so as to adhere to the outer peripheral surfaces of the feeding rollers 6a and 6b in the form of films, respectively.
The conductive paste 4 on the outer peripheral surfaces of a and 6b is an intermediate roller 3 which is arranged apart from the feeding rollers 6a and 6b.
When the toner is transferred to the outer peripheral surfaces of a and 3b, the intermediate roller 3
a is widely extended in the axial direction on the outer peripheral surfaces of a and 3b, and is formed on the outer peripheral surfaces of the coating rollers 2a and 2b in a substantially uniform and stable manner over the entire axial direction of the coating rollers 2a and 2b. To be done. In this way, the conductive paste 4
To the outer peripheral surfaces of the application rollers 2a and 2b on which
The longitudinal side edges A3 ′, A3 ″ of the rod-shaped substrate piece A3 are moved closer to each other by the forward movement of the clamper 1 to move the rod-shaped substrate piece A3.
The conductive paste 4 is applied to the longitudinal side edges A3 ′, A3 ″ of the.

In this case, the longitudinal side edges A3 ', A3 "of the rod-shaped substrate piece A3 are immersed in the conductive paste 4 formed in a substantially uniform thickness without contacting the outer peripheral surfaces of the coating rollers 2a, 2b. Since they are stacked, it is possible to apply a stable amount of conductive paste to the rod-shaped substrate piece A3 without causing defects such as cracking or chipping, etc. In the present embodiment, the intermediate roller, the feeding roller, and The separation distance from the coating roller is about 0.03 mm, but the present invention is not limited to this, and it is 0.02 mm to 0.02 mm.
When the thickness is about 5 mm, the conductive paste can be formed with a constant thickness on the outer peripheral surface of each roller, so that the conductive paste can be applied in a stable state on the long side edges of the rod-shaped substrate piece.

Further, as the conductive paste used in this embodiment, a conventionally used one such as a mixed paste of silver and epoxy resin or a mixed paste of silver and glass can be widely used. . Further, in the present embodiment, both the application rollers 3 and 4 have a cylindrical shape made of porous resin, but the present invention is not limited to this, and the material can be processed into a cylindrical shape. If this is used, it can be widely used, and the application rollers 2a, 2
Regarding the outer peripheral surface shape of b, if the shape corresponding to the outer shape of the object to be coated H is adopted, even if the object to be coated has a complicated outer shape as shown in FIG.
The conductive paste on the outer peripheral surface of can be easily applied.

[Brief description of drawings]

FIG. 1 is a perspective view showing a dividing step of dividing a substrate into rod-shaped substrates in manufacturing a chip resistor.

FIG. 2 is an explanatory diagram for explaining a device for applying a conductive paste for a terminal electrode film in the chip resistor of the present invention.

FIG. 3 is a perspective view of an essential part showing a device for applying a conductive paste for a terminal electrode film in the chip resistor of the present invention.

FIG. 4 is an explanatory view for explaining how the rod-shaped substrate clamped by the clamper is brought closer to the coating roller in the coating device for the conductive paste of the terminal electrode film in the chip resistor of the present invention.

FIG. 5 is an explanatory diagram for explaining the outer shape of the coating roller corresponding to the outer shape of the object to be coated in the coating device for the conductive paste of the terminal electrode film in the chip resistor of the present invention.

FIG. 6 is a main part perspective view showing a conventional terminal electrode film coating apparatus.

FIG. 7 is a cross-sectional view of essential parts showing a conventional terminal electrode film coating apparatus.

FIG. 8 is an enlarged cross-sectional view showing a coating state of a conventional terminal electrode film.

FIG. 9 is an explanatory diagram illustrating a conventionally proposed coating device for a terminal electrode film.

[Explanation of symbols]

 1 Clamper 2 Application Roller 3 Intermediate Roller 4 Conductive Paste 5 Tank 6 Feeding Roller 7 Scraper

Claims (2)

[Claims] 1. At least one roller is provided between an intermittent rotation type application roller whose axis is substantially horizontal and an intermittent rotation type feeding roller whose lower portion is immersed in a conductive paste in a tank containing the conductive paste. The two intermediate rollers are rotatably arranged such that the intermediate roller is separated from both the applying roller and the feeding roller, and are arranged at a side portion of the applying roller in parallel with the axis of the applying roller. A clamper for the provided chip resistor is provided so as to reciprocate between a forward position where the chip resistor approaches the outer peripheral surface of the coating roller and a retracted position from the coating roller when the rotation of the coating roller is stopped. A coating device for a terminal electrode film in a chip resistor. 2. The distance between the intermediate roller and each of the coating roller and the feeding roller is 0.0.
The coating device for a terminal electrode film in a chip resistor according to claim 1, wherein the coating device has a thickness of 2 mm to 0.05 mm.