JP2007160643A - Screen printing implement, screen printing machine and screen printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set a heat capacity for melting ink to be large, to reduce the nonuniformity in temperature and viscosity of the ink according to a place and to eliminate the nonuniformity in a printing state, in screen printing. <P>SOLUTION: This screen printing implement 100 is designed for screen printing of a printing object 240 by a screen plate. The implement has a heater 150 which supplies heat, an ink storing part 130 which stores the ink 170 and heats it by the heat supplied from the heater 150, and a tip part 140 which conducts printing, discharging the ink 170 heated in the heat storing part 130 from a slit 160. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a screen printing tool, a screen printing machine, and a screen printing method for performing screen printing on a printing material using a screen plate, for example.

In conventional screen printing, the squeegee slides linearly in contact with the upper surface of the screen plate, and the ink is forcibly filled into the pattern apertures of the screen plate by the sliding, and printed on the printing material through the apertures. To do. For this reason, in order to achieve uniform printing quality or finished state, improvement in printing accuracy, and the like, it is a problem to prevent a change in ink viscosity during each printing. In particular, when screen printing is performed on a printed circuit board or the like, it is possible to always reduce the size of a printed material such as a printed circuit board so that ink having a certain viscosity suitable for printing can be supplied.
As a known technique of screen printing, for example, as shown in Patent Document 1, there is a screen printing method in which cream solder is heated with a squeegee. However, it has not yet been solved about the problem of sufficiently increasing the heat capacity for melting the ink, reducing the variation in temperature and viscosity of the ink depending on the location, and finally suppressing the variation in the printing state.
In addition, in a screen printing machine, a drying furnace for drying ink is an indispensable facility because it takes time to dry the ink. However, the drying furnace occupies a large space, so that the screen printer has a large facility. As a result, there is a problem that the equipment cost becomes high.
JP-A-2005-001118

  In view of the above problems, the present invention, for example, in a screen printing tool, a screen printing machine, and a screen printing method for screen printing on a printing material using a screen plate, takes a large heat capacity for melting ink, and varies in temperature depending on the location of the ink. The purpose is to eliminate variations in printing state by suppressing variations in viscosity and viscosity. Another object of the present invention is to shorten the drying time by using hot-melt ink for screen printing, omit the equipment of the drying furnace, and reduce the equipment cost.

The screen printing tool of the present invention,
A screen printing tool for performing screen printing on a substrate by a screen plate, a heater for supplying heat, an ink storing unit for storing ink, and heating the ink by the heat supplied from the heater, and heating by the ink storing unit A screen printing tool comprising: a tip portion that prints while discharging the discharged ink from the slit.

In addition, the screen printing tool of the present invention,
The screen printing tool according to claim 1, wherein a portion of the tip that contacts the screen plate is diamond sprayed.

In addition, the screen printing tool of the present invention,
The screen printing tool according to claim 1, wherein a portion of the tip portion that comes into contact with the screen plate is subjected to a canak process.

In addition, the screen printing tool of the present invention,
The tip portion is a screen printing tool characterized in that it is composed of two blocks forming the slit therebetween.

The screen printing machine of the present invention is
A screen printing machine for printing on an object to be printed with a screen plate, comprising the screen printing tool.

The screen printing machine of the present invention is
A screen printing machine for printing on an object to be printed using a screen plate, wherein the screen printing machine comprises a screen plate for melting ink by heat generated by passing an electric current.

The screen printing method of the present invention includes:
In the screen printing method, the ink is heated in the ink storage unit, and then the ink is ejected from the slit at the leading end portion so that the screen printing is performed by superimposing the screen plate on the printing material.

  According to the present invention, it is possible to maintain a sufficient melting temperature for melting the hot melt ink during screen printing, and it is possible to suppress the occurrence of variations in the temperature and viscosity of the hot melt ink, depending on the printing location. There is an effect of eliminating variations and improving the printing state.

  In addition, according to the present invention, it is possible to suppress the generation of ink solvent by using hot melt ink, and further, a drying furnace that occupies a large specific gravity in terms of space and money as a system is unnecessary. The system becomes simple, and there is an effect of greatly reducing the occupied space and equipment cost.

Embodiment 1 FIG.
The first embodiment will be described with reference to FIGS. First, a die (an example of a screen printing tool) will be described. FIG. 1 is a longitudinal sectional view of a die (an example of a screen printing tool) in this embodiment. FIG. 2 is a perspective view of the die in this embodiment. Here, the die is a screen printing head used in a screen printing machine, which temporarily stores ink and discharges the ink onto a screen plate when printing. A squeegee head of a conventional screen printing machine It is a replacement for the part.
The die 100 is made of, for example, iron or stainless steel, and includes an ink storage unit 130 that temporarily stores and heats the hot melt ink 170 (an example of ink), and a hot melt ink 170 that is heated by the ink storage unit 130. A tip portion 140 for discharging is provided. The ink storage unit 130 includes, for example, a cylindrical cavity therein, and stores hot melt ink in the cavity. The front end portion 140 includes a gap (slit 160) connected to the ink storage unit 130, and the hot melt ink 170 stored in the ink storage unit 130 is discharged from the discharge port 161 through the gap.

The die 100 also includes a heater 150 that supplies heat to the hot melt ink 170 stored in the ink storage unit 130. In FIG. 1, the heater 150 has a bar shape, and the heater 150 is installed in close contact with a part of the ink storage unit 130. This is an example of a method of installing the heater 150, and a band heater (band-shaped electric heater) or a tape-shaped heater may be installed around the die 100. In addition, a heating wire wound in a coil shape is inserted into a protection tube of a card ridge type heater (stainless steel (or copper, brass)) into the die 100 and filled with a special powder having high thermal conductivity and high insulation and solidified. A pipe-shaped heater) may be directly embedded in the die.
The ink is assumed to be hot melt ink 170 that melts by heat, but may be solder paste as long as it melts by heat.
The hot melt ink is, for example, a solid substance or a clay-like substance that maintains a constant shape at room temperature, but melts when given constant heat to become a fluid ink. By utilizing this property, it is possible to perform printing in a shorter time than conventional ink by transferring to a printing material in a liquefied state by applying heat and drying at room temperature.
The die 100 is warmed by the heat of the heater 150, and the hot melt ink 170 stored in the ink storage unit 130 is melted by the heat of the die 100 to maintain a constant viscosity. The melted hot melt ink 170 is discharged to the outside from the slit 160 of the tip portion 140 due to the pressure applied to the ink reservoir 130. A method for applying pressure to the ink storage unit 130 will be described later. For example, the discharged hot melt ink 170 is transferred to the work 240 (an example of a substrate) through the opening 231 of the screen plate 230.

  The die 100 is composed of two blocks, a block a110 and a block b111, which form a slit 160 therebetween. This is divided into two blocks in order to adjust the distance between the tip portion 140 of the die 100 and the screen plate. For example, if either the tip of the block a110 or the block b111 is worn by contacting and moving with the screen plate 230 and the distance from the screen plate changes, there is a possibility that ink cannot be ejected normally. . When the die is integrally formed, the height must be adjusted by polishing the tip portion 140 or the like. However, by constructing the die with two blocks, either the block a110 or the block b111 is used. By moving up and down, it is possible to adjust the height of the tip 140 in contact with the screen.

Next, an example when the die 100 (an example of a screen printing tool) according to the present embodiment is attached to the screen printer 200 will be described with reference to FIGS.
FIG. 3 is a diagram schematically showing the configuration of the screen printer when the die 100 according to the present embodiment is attached to the screen printer.
FIG. 4 is a front view of the screen printing machine when the die 100 according to the present embodiment is attached to the screen printing machine.
FIG. 5 is a plan view of the screen printing machine when the die 100 according to the present embodiment is attached to the screen printing machine.
First, the configuration of the screen printing machine 200 will be described.
The screen printing machine 200 includes a die attachment plate 210 for attaching the die 100 according to the present embodiment. The die 100 is attached and fixed to the die attachment plate 210, and printing is performed by moving the die attachment plate 210 in the printing direction. At both ends of the die attachment plate 210, an up / down adjustment mechanism 265 for adjusting the distance between the screen plate 230 and the die 100 is provided. By using the vertical adjustment mechanism 265, the distance between the die 100, the screen plate 230, and the work 240 (an example of a substrate) is adjusted. In addition, slide guides 266 are provided at both ends of the die attachment plate 210, and the screen printing machine 200 is driven along a slide shaft 267 in a certain direction by a ball screw, a belt, or the like, like a normal squeegee unit. Is possible. By attaching the motor 268, the die attachment plate 210 can be automatically moved.

  The screen printing machine 200 includes a hot melt tank 260 (an example of an ink supply tank) that supplies ink to the die 100. The hot melt tank 260 and the die 100 are connected by a pipe 261, and the hot melt ink 170 is supplied from the hot melt tank 260 through the pipe 261 to the die 100. The hot melt tank 260 and the pipe 261 are provided with a heater 264 for keeping the hot melt ink 170 in a molten state and keeping the temperature. When the current flows through the heater 264, the hot melt tank 260 and the pipe 261 are heated, and the hot melt ink 170 is in a molten state and can flow to the die 100.

A pump 262 is installed in the middle of the pipe 261, and the hot melt ink 170 is supplied from the hot melt tank 260 to the die 100 through the pipe 261 by the pressure applied by the pump 262. The method of supplying the hot melt ink by attaching the pump 262 is an example, and the hot melt ink is supplied by the pressure generated in the hot melt tank 260 by sending air such as nitrogen gas into the hot melt tank 260. 170 may be supplied to the die 100.
Further, the die attachment plate is provided with a tube attachment port 263. The tube attachment port 263 allows the tube 261 extending from the hot melt tank 260 and the die 100 to be easily connected.
The screen frame 232 is a fixing tool for fixing the screen plate 230.
The screen plate 230 is, for example, a wrinkle (screen) woven with fibers such as polyester, and this screen is stretched and fixed to the screen frame 232, and a plate film (resist) is formed thereon to form a necessary image line. An opening 231 is provided by closing the eyes other than. By passing the ink through the opening 231 of the screen plate 230, the ink can be transferred and printed on the work 240 (an example of the substrate).
The work table 250 is a table on which a work 240 (an example of a substrate to be printed) is placed.

Next, features of the tip portion of the die 100 will be described.
In a conventional screen printing machine, ink is placed in a frame of a screen plate, and the ink is pushed by a squeegee, thereby passing through the opening of the screen plate and transferring the ink to a printing material for printing. When a conventional squeegee is used, the squeegee must be installed so that it can form an angle of 90 degrees or less with the screen plate in the advancing direction. . If the ink goes out to the outside, heat cannot be sufficiently transmitted to the ink, so that there is a possibility that sufficient heat cannot be secured. That is, when a sufficient heat capacity cannot be secured, the temperature variation increases depending on the location, the viscosity also varies, and finally the printing state also varies depending on the location.
If the die 100 according to the present embodiment is used, heat can be supplied to the hot melt ink 170 by the heat of the heater up to the tip portion, so that sufficient heat can be secured.

Further, the die 100 according to the present embodiment is applied so that the slit 160 is substantially perpendicular to the screen plate 230, and the height of the portion where the tip portion 140 of the die contacts the screen plate 230 is the same height. Thus, even when the discharge port 161 of the die 100 moves on the screen plate 230, the hot melt ink 170 is prevented from largely coming out of the die 100.
The transfer of the hot melt ink 170 to the printing material is performed by the pressure applied to the hot melt ink 170 from the pump 262 or the hot melt tank 260. By doing so, it is possible to perform printing while sufficiently supplying heat to the hot melt ink 170.

Further, conventionally, since the squeegee is installed so that an angle of 90 degrees or less with respect to the screen plate is formed, the printing direction is limited to one direction, but when the die 100 according to the present embodiment is used. It is possible to print in both directions. Therefore, an operation for returning the squeegee to a predetermined position is not necessary, and printing can be performed by reciprocating the die 100. As a result, the printing time can be shortened.
In addition, when the height of the tip portion 140 of the die 100 according to the present embodiment that is in contact with the screen plate 230 is not the same, the discharge port 161 becomes large, so that the screen plate due to the pressure from the pump 262 or the hot melt tank 260 is used. The hot melt ink 170 cannot be pushed in. Since pressure cannot be applied by pressure from the pump 262 or the like, ink must be pushed in using a squeegee or the like in order to print. In addition, since it is considered that the ink may largely come out of the die, the viscosity stability may not be maintained.

In addition, since the die head tip (an example of the tip portion 140) of the die 100 according to the present embodiment is in direct contact with the screen plate, it is necessary to consider the wear and increase the strength to prevent wear. . In order to increase the strength of the surface of the die head tip (tip portion 140), for example, there is a method of diamond spraying the die head tip (tip portion 140). Further, for example, the tip of the die head (tip portion 140) may be subjected to a canak process (special nitriding process).
Diamond spraying is a technique for improving the surface characteristics of mechanical parts and the like by, for example, forming a film in which diamond powder particles are dispersed using a spraying technique. The thermal spraying technique is a processing method in which a material heated and melted and softened by a heat source is sprayed onto a substrate surface to form a coating.
The canak process is a kind of vacuum nitrogenation method performed in a high vacuum. The Kanak treatment is based on the diffusion principle of nitrogen atoms in a vacuum furnace. For example, NH3 and a nitriding promotion gas are sent into a vacuum furnace and the temperature is heated to 480 to 550 degrees for 3 hours. This is a method in which a heating time of 15 hours is maintained and nitrogen is diffused into the base material to generate alloy elements and compounds.
The die head tip (tip portion 140) is subjected to diamond spraying or canak treatment, whereby the strength of the die head tip (tip portion 140) is increased and wear due to contact with the screen plate can be prevented. The number of maintenance of the screen printer 200 such as replacement can be reduced, and printing can be performed for a longer time.
Because the processing is aimed at preventing wear on the tip due to wear, if the tip material can be sufficiently strong due to the material and material of the die, it does not need to be processed and the tip strength is secured. In order to do this, other processing may be performed.

  The die 100 is composed of two blocks, a block a110 and a block b111, which form a slit 160 therebetween. This is because, when screen printing is performed, the distance between the tip of the block a110 and the block b111 and the screen plate changes due to wear, and hot melt ink may protrude. Therefore, when the slit 160 of the die 100 is formed so as to be divided into a block a110 and a block b111 and worn by printing, either one of them is moved up and down to remove from the screen plate. The distance can be adjusted to be the same.

Next, the screen printing method according to the present embodiment will be described with reference to FIG.
FIG. 8 is a flowchart showing the screen printing method according to the present embodiment.
First, the hot melt ink 170 is put into the hot melt tank 260 in the first step (S101). The hot melt tank 260 stores sufficient hot melt ink 170 for printing.
In the next step (S102), the hot melt ink 170 is melted by the heat of the heater 264 provided in the hot melt tank 260.
When the hot melt ink 170 stored in the hot melt tank 260 is sufficiently melted, the hot melt ink 170 is sent to the die 100 through the tube 261. The hot melt ink 170 is sent to the ink storage unit 130 of the die 100 until it is full, and is stored until printing (S103).
Next, the hot melt ink 170 of the ink storage unit 130 is melted by the heat of the heater 150 of the die 100 so as to have a viscosity sufficient for printing (S104).
Next, pressure is applied to the pump 262 or the hot melt tank 260 to push out the hot melt ink 170 from the slit 160 (S105).
The hot melt ink 170 passes through the mask (opening 231) of the screen plate 230 and is transferred to the printing material (S106).
In step 107, it is confirmed whether printing is completed (S107). If printing has not been completed (in the case of NO), the process returns to step 103, and the hot melt ink 170 is sent to the die 100 again. If printing has been completed (YES), printing is terminated.

As described above, the screen printing tool according to the present embodiment is
A screen printing tool for performing screen printing on a substrate by a screen plate, a heater for supplying heat, an ink storing unit for storing ink, and heating the ink by the heat supplied from the heater, and heating by the ink storing unit And a leading end portion for printing while discharging the discharged ink from the slit.

  The screen printing machine of the present embodiment is a screen printing machine provided with the screen printing tool.

  Due to these features, it is possible to maintain a sufficient melting temperature for melting the hot melt ink during screen printing, suppressing the occurrence of hot melt ink temperature variation and viscosity variation, and depending on the printing location. There is an effect of eliminating variations and improving the printing state.

  In addition, according to the present embodiment, it is possible to suppress the generation of ink solvent by using hot melt ink, and further, a drying furnace that occupies a large specific gravity in terms of space and money as a system is unnecessary. As a result, the system becomes simple and the space and equipment costs are greatly reduced.

Embodiment 2. FIG.
The second embodiment will be described with reference to FIGS.
FIG. 6 is a cross-sectional view schematically showing the configuration of the screen printing machine according to the second embodiment.
FIG. 7 is a plan view of the screen printing machine according to the second embodiment.
The difference from the first embodiment is that a Joule heat generation wiring 270 is provided around the screen plate. A current is passed through the wiring for generating Joule heat installed in the screen plate at a certain voltage, Joule heat is generated in the screen itself, and the melting temperature of the hot melt ink is maintained. Since the configurations of the die 100 and the screen printing machine 200 are the same as those of the first embodiment, the description thereof is omitted here. Of course, the die 100, the hot melt tank 260, and the pipe 261 are also equipped with heaters, so The melted state of the melt ink is maintained.
By using together the heat from the die 100 provided with the screen plate 230 having the Joule heat generation wiring 270 and the Joule heat capacity being increased and the heater 150, the hot melt ink 170 can be more stably kept in the molten state. Therefore, it is possible to obtain a better printing state.

  Of course, it is conceivable that the hot melt ink 170 is melted only by the Joule heat of the screen plate and printed with a squeegee like a normal screen printer, but the Joule heat capacity cannot be increased with the screen plate alone. The variation in the viscosity also increases, and the viscosity also varies. That is, the printing state also varies depending on the location. In order to suppress this, by using the Joule heat of the screen plate and the heat of the die 100 in combination, the molten state of the hot melt ink 170 is stabilized, and the printing state is not varied depending on the location.

As described above, the screen printing machine according to the present embodiment is
A heater for supplying heat, an ink storage unit for storing ink and heating the ink by the heat supplied from the heater, and a leading end portion for printing while discharging the ink heated by the ink storage unit from the slit are provided. A screen printing machine comprising: a screen printing tool characterized by the above; and a screen plate that melts ink by heat generated by passing an electric current.

  Due to these features, it is possible to maintain a sufficient melting temperature for melting the ink during screen printing, suppressing variations in ink temperature and variations in viscosity, eliminating variations due to printing locations, It is possible to improve the printing state.

It is a longitudinal cross-sectional view of the screen printing tool which concerns on this Embodiment. It is a perspective view of the screen printing tool which concerns on this Embodiment. It is sectional drawing which shows typically the structure of the screen printer concerning this Embodiment 1. FIG. 1 is a front view of a screen printing machine according to a first embodiment. 1 is a plan view of a screen printing machine according to a first embodiment. It is sectional drawing which shows typically the structure of the screen printer concerning this Embodiment 2. FIG. It is a top view which shows typically the structure of the screen printer concerning this Embodiment 2. FIG. It is a flowchart which shows the screen printing method which concerns on this Embodiment.

Explanation of symbols

  100 die, 110 block a, 111 block b, 130 ink storage unit, 140 tip, 150 heater, 160 slit, 170 hot melt ink, 200 screen printing machine, 210 die mounting plate, 230 screen plate, 231 opening, 232 Screen frame, 240 work, 250 work table, 260 hot melt tank, 261 pipe, 262 pump, 263 pipe attachment port, 264 heater, 265 vertical adjustment mechanism, 266 slide guide, 267 slide shaft, 268 motor, 270 wiring for heat generation .

Claims (7)

A screen printing tool for screen printing on a substrate by a screen plate,
A heater for supplying heat;
An ink storage unit that stores ink and heats the ink by heat supplied from the heater;
A screen printing tool comprising: a tip portion that prints while discharging ink heated in an ink storage portion from a slit. 2. The screen printing tool according to claim 1, wherein a portion of the tip portion that contacts the screen plate is diamond sprayed. 2. The screen printing tool according to claim 1, wherein a portion of the tip portion that contacts the screen plate is subjected to a canak process.   The screen printing tool according to any one of claims 1 to 3, wherein the tip portion is composed of two blocks that form the slit therebetween. In a screen printing machine that prints on a substrate with a screen plate,
A screen printing machine comprising the screen printing tool according to any one of claims 1 to 4. The screen printing machine further includes:
6. The screen printing machine according to claim 5, further comprising a screen plate that melts ink by heat generated by flowing an electric current. A screen printing method in which screen printing is performed by superimposing a screen plate on an object to be printed by heating the ink in the ink storage unit and then discharging the ink from the slit at the tip.

Images