JPS61286133A - Printing and its device - Google Patents

Abstract

PURPOSE:To surely supply ink to the material to be printed and to facilitate printing of a desired pattern, by suing a screen printing plate and by applying the ink to the material to be printed which is located below, by passing the ink through a screen gauze of an image portionunder its own weight or by pressure. CONSTITUTION:A screen printing plate 1 is provided with a screen gauze 5 and a non-perforated layer i.e. a resist 2 which fills the perforation therein, and the resist 2 has openings with shapes corresponding to the printing pattern, and these openings form the image portions 3, and the rest form non-image portions 4. On the upper surface of the screen printing plate 1, cell forming members 7 that form ink cells 6 to surround respective image portions 3 are installed. Connecting pipings 8 to introduce and supply ink from tanks 9 are connected and sealed to the top of the respective ink cells 6. A pulse control air pump consisting of an air pulse control portion 12 and a compressor 13 is connected to the upper portions of respective ink tanks 9. A pressure is applied to the ink tanks 9, and the ink is discharged by pressure through the screen gauze 5 of the image portions of the screen printing plate 1 to carry out printing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for printing printed matter consisting of a single color or a plurality of colors, and in particular to a method and apparatus for printing printed matter consisting of a single color or a plurality of colors, and particularly for printing a printed matter in which various tones are printed at different positions, such as printing of color samples. The present invention relates to a printing method and apparatus suitable for.

[Conventional technology]

When producing multi-colored printed matter, conventional printing technology uses the subtractive color mixing method, which uses the four basic primary colors (YMCB &) or several types of auxiliary spot colors as necessary, and prints one overprint according to a color-separated plate of the printing original. Print reproductions of various tones are being carried out.

Although this method has the great advantage of being able to express gradation in photographs, etc., it is not strictly possible to express all tones (hue, brightness, saturation) with a limited number of basic colors. It is possible. In particular, it requires a large number of colors from 4 to 7 or more,
If it is not possible to re-dedicate each color tone by overprinting basic colors, the printing process will be repeated by printing as many color units as each printing machine has and repeating the same printing process until the desired number of colors is achieved.
Problems such as repeat printing accuracy and yield often occur.

Therefore, for all colors corresponding to the desired number of colors.

We prepare ink with strict color 1Piffl in advance,
It would be a great advantage if this ink could be used to print gold at the same time in a predetermined position.

For this purpose, Japanese Patent Laid-Open Nos. 50-54411 and 56-97573 have already been proposed.

In the method disclosed in JP-A-50-54411, a liquid (ink) is supplied to a container having a porous horizontal opening (for example, a screen) on the upper surface, and the surface of the liquid is never higher than the horizontal opening, but the horizontal opening is always maintained. This is a method of printing by pressing a base to be printed from above against a horizontal opening in a moist state.

Also, the method disclosed in Japanese Patent Application Laid-Open No. 56-97573.

A matrix plate, which has a depression in the shape of the print pattern to be printed on its lower surface, is pressed against the base to be printed.

This is a method in which liquid (ink) is supplied to the matrix chamber formed by the printing base and the depressions of the matrix plate using a metered discharge pump.

[Problem that the invention seeks to solve]

However, all of the methods disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Sho have problems. That is, in the former case, the liquid level of the supply container that supplies liquid to the container below the porous screen that forms the horizontal opening is set at a position that is at least not higher than the top surface of the screen, and the liquid level is configured so as not to be higher than the screen. Therefore, the ink supply power to the screen is almost zero. Therefore, it is actually due to the capillary phenomenon to the screen, and is affected by the viscosity of the liquid, surface tension, etc.
Particularly when handling a wide variety of liquids, this becomes an area that is difficult to control mechanically. Furthermore, since the screen is located on the top surface, dust generated in the two working environments tends to adhere to the screen, which is disadvantageous in terms of maintenance. As a result of these, there are difficulties in industrial productivity.

Regarding the latter, although the above problems have been resolved.

There is a new problem. That is, if pump syringes, matrix plates, etc. are manufactured to satisfy the technical purpose and precision of this method, they will be extremely expensive, and when replacing ink, the pump, matrix plates, etc. will require troublesome cleaning work. In particular, when dealing with a wide variety of products in small quantities, it is not economical in terms of equipment cost and work.

The present invention solves both the technical and economical problems of the prior art and provides an industrially useful printing method and apparatus.

[Means for solving problems]

In the present invention, first, as a printing form, screen printing, which has a proven track record in many fields, is used as a basic printing method.

This method is suitable for producing a large variety of products in small quantities because the manufacturing cost of the screen printing plate is low.

Next, the method of passing the ink through the image area of the screen printing plate and applying it to the printing base below is either a method that utilizes the weight of the ink supplied onto one image area by pushing with a conventional squeegee, or Change to a method that applies pressure to the ink. That is, in the method of the present invention, ink is supplied so as to cover the entire area of the image area of the screen printing plate, and the ink is caused to pass through the screen gauze in the image area by its own weight or pressure and adhere to the printing base below it. It is characterized by

At this time, it is preferable to form a non-porous layer that forms a non-image area on the back side of the screen printing plate at least on the back side of the screen printing plate. When the screen printing plate and the printing base are brought into close contact, a space is formed between the screen gauze and the printing base in the two printing areas, so by keeping the screen printing plate and the printing base in close contact until this space is filled with ink. , it is possible to apply a fixed amount of ink determined by the volume of the space, and the amount of ink to be applied can be easily adjusted.

On the other hand, it is preferable to provide an ink cell surrounding the image area on the top surface of the screen printing plate so that ink can be reliably supplied to the entire area of one image area and the amount of ink used can be reduced. When using ink discharge using its own weight,
The ink cell may be directly exposed to the atmosphere, or an ink tank may be sealingly connected to the ink cell and the ink tank may be exposed to the atmosphere.

In the case where the ink is pressurized and discharged, the ink pressurizing means preferably applies gas pressure, such as air pressure, to the ink and controls the air pressure. The higher the pressure applied, the greater the amount of ink ejected and the shorter the printing time. However, if it is too high, ink will leak between the non-printing area of the screen printing plate and the printing base, preventing the desired printing. I can't find a pattern. When using a normal screen printing machine to bring the screen printing plate and the printing base into close contact, it is not possible to increase the contact pressure between the non-printing area surrounding the two printing areas and the printing base, so the ink It is desirable to use a low pressure of atmospheric pressure + 1 kg/cd or less as the pressurizing pressure. Of course.

It is possible to increase the ink pressure by increasing the contact pressure between the non-image area surrounding the image area of the screen printing plate and the printing base by appropriate means.

In that case, high-speed and stable printing becomes possible, and productivity can be increased. During printing, the air pressure applied to the ink is set to the level necessary to send the ink through the screen gauze, but when not printing (while the printing base is separated from the screen printing plate), the air pressure applied to the ink is maintained to allow the ink to flow out naturally due to its own weight. It is preferable to use a reduced pressure state to prevent this. In addition,
Even when the ink is ejected through the screen gauze using only its own weight, reduced pressure may be applied to the ink during non-printing.

The apparatus of the present invention for carrying out the above method includes: a screen printing plate; an ink cell attached to the upper surface of the screen printing plate and surrounding the image area of the printing plate; an ink tank connected to the ink cell in a sealed relationship; It is characterized by comprising a pressure control means for controlling the pressure in the ink tank, and a drive means for bringing the back surface of the screen printing plate into close contact with the base to be printed.

In the above apparatus, a plurality of printing areas are provided on the screen printing plate, each printing area is provided with an ink cell, and each ink cell is connected to an independent ink tank.

Each ink tank contains different inks with different color tones (multi-color printing is possible at the same time).

In a preferred embodiment, an air pump is used to control the air pressure above the ink in the ink tank as the pressure control means for controlling the pressure in the ink tank. Furthermore.

During printing, the pressure inside the ink tank is maintained at the level necessary to send the ink through the screen gauze, but when not printing, the pressure is reduced to prevent natural supply of ink due to the difference in liquid column between the ink tank liquid level and the bottom surface of the screen gauze. Therefore, it is preferable to apply pressure in conjunction with the printing cycle.

A pulse-controlled air pump that can repeatedly provide reduced pressure is preferred.

(Example) The present invention will be described in further detail using preferred examples of the present invention shown in the following nine drawings.

FIG. 1 is a sectional view schematically showing the entire printing apparatus as a preferred embodiment of the present invention. 1 is a screen printing plate, which is held on a support stand 19. The screen printing plate 1 has a screen gauze 5 and a non-porous layer, ie, a resist 2, for covering the screen gauze 5, and the resist 2 protrudes from the lower surface of the screen gauze 5. The resist 2 has an opening having a shape corresponding to the printed pattern, and the opening forms an image area 3 and the other area forms a non-image area 4. The screen printing plate 1 can be the same as those conventionally used. For example, the screen gauze 5 can be made of polyester, nylon, stainless steel, etc., and the resist 2 can be made of photosensitive resin, metal mask, etc. The screen gauze 5 in the printing area 3 may be treated by spraying a suitable plate release agent 9 such as stearic acid, lecithin, etc. The thickness t of the resist 2 below the screen gauze 5 is the main factor in the coating amount. The roughness of the mesh, the thickness of the screen filament, the aperture ratio, etc. are related to the discharge time.

On the upper surface of the screen printing plate 1, a cell forming member 7 for forming ink cells 6 surrounding each printing area 3 is formed by a suitable means.
For example, it can be attached in a sealed state with double-sided tape.

The ink cell 6 is provided especially for ink separation when multiple color inks are supplied onto the same printing plate, and to prevent the flow velocity distribution of the ink flowing from the connecting portion from directly entering the screen gauze 5 in the printing area. Its material is rubber.

It may be a plastic cutout, a cast molded product, or a molded product, and a disposable and inexpensive material that can withstand the ink used can be selected. Note that the cell forming member 7
does not necessarily have to be an integral structure, and may have a two-layer structure of a lower layer forming the side surface of the ink cell 6 and an upper layer forming the upper surface of the ink cell 6. In this case, the lower layer is a photosensitive layer formed on the upper surface of the screen printing plate 1. By applying a resin to an appropriate thickness, exposing and developing it, or by applying a less fluid sol around the image area and curing it,
It can be easily formed. Seen from above, each ink cell 6 only needs to have a cross-sectional shape larger than the image area 3 of the screen printing plate; in other words, it is not necessary to match the shape of the image area 3, making manufacturing easy. It is. As needed,
The cell-forming member 7 may be connected to the frame IA of the screen printing plate 1 using suitable fixing means or to another suitable support frame (not shown). In this way, as will be described later, when the printing base 16 is pressed against the back surface of the screen printing plate 1, the contact pressure between the screen printing plate l and the printing base 16 at the cell forming member 7 can be increased. This is preferable. In addition, depending on the case.

A metal cell forming member may be used, or as a simple form, as shown in FIG. 4, a disposable syringe 28 is adhesively fixed so as to cover the printing area 3, and an ink cell is formed with the syringe. Good too.

In FIG. 1, an ink tank 9 is placed above each ink cell 6.
A connecting pipe 8 for supplying and introducing ink is connected and sealed. The other end of the connecting pipe 8 is an ink tank 9 for each ink.
The connection is sealed at the bottom. Thus, each ink cell 6 and ink tank 9 are connected in a sealed relationship. Connecting pipe 8
The material is selected from rubber, plastic, metal rings, and materials that are resistant to ink, but flexibility and transparency are also required in some cases. The diameter and length of this tube both affect the discharge time. The material of the ink tank 9 is also preferably the same as that of the connecting pipe 8. All of these are considered disposable, but disposable plastic syringes are particularly convenient when the ink tank is used in small quantities.

At the top of each ink tank 9 there is one branch pipe 10. A pulse-controlled air pump consisting of an air pulse controller 12 and a compressor 13 is connected via an air hose 11 . The pulse control air pump used here is one that repeatedly pressurizes and depressurizes the upper space of the ink tank at predetermined intervals via the air hose 11, so any known type can be used. Explanation will be omitted. In FIG. 1, air pressure from one air pulse control section 12 is applied to each ink tank 9, but instead, as shown in FIG. 3, an air pulse control section is provided corresponding to each ink tank 9A. Connect 12A.

The pressure within each ink tank 9A may be individually controlled. In the case of FIG. 4, since the syringe 28 serves both as an ink cell and an ink tank, the air hose 11 is connected to its upper end.

The pressure applied to the ink tank is atmospheric pressure + 1 kg.
/cm3 or less, *Pressure is preferably about the same as or slightly less than the weight of the liquid column from the lower surface of the screen gauze 5 to the ink liquid level in the ink tank in FIG. When the reduced pressure is selected in this manner, the ink pressure at the lower surface of the screen gauze when reduced pressure is applied becomes approximately equal to atmospheric pressure, thereby preventing ink from flowing out. Note that as printing progresses, the liquid level decreases, and ink may flow out at the same degree of pressure reduction. Therefore, as shown in Figure 7A, an ink tank 9B with a large inner diameter near the ink liquid level is used to lower the liquid level. Reduce the pressure drop (and reduce the frequency of pressure reduction adjustment).

As shown in FIG. 7B, it is preferable to incorporate a level sensor 33 into the ink tank 9 and send a signal obtained by the level sensor 33 to the air pulse control section 12 to automatically control the degree of pressure reduction.

In FIG. 1, below the screen printing plate l.

An XY stage 15 and its vertical drive device 18 are provided as driving means for supporting the printing target base 16 and bringing it into close contact with the screen printing plate 1. These can be those used in ordinary screen printing machines. Note that the driving means may be of a type that moves the screen printing plate 1 up and down. The vertical drive device 18 is connected to the air pulse control section 12 via the switch 14, and the stage 15 moves up and down according to the cycle of pressurization and depressurization by the pulse-controlled air pump. Generally, a vacuum method is preferable for setting the base 16 to be printed on the stage 15. As shown in FIG. 16 is suctioned and held so that it does not shift. If the cell forming member 7 to be attached to the top surface of the screen printing plate 1 is made of a hard material such as metal, a soft rubber plate 31 having suction holes between the stage 15 and the printing base 16 as shown in FIG. It is good to put

Next, a printing method using the above apparatus will be explained with reference to FIGS. 2A to 2D. Incidentally, each ink tank 9 contains ink prepared to have a predetermined color tone, and this ink fills the connecting pipe 8 and the ink cell 6 on the screen gauze 5.

(2) Paper Feeding (FIG. 2A) While the stage 15 is in the lowered position, the printing base 16 is supplied and held on the stage. During this time, the air pump is applying reduced pressure to the ink tank 9.

Natural outflow of ink from the printing area 3 is prevented.

■ Close contact (Figure 2B) The stage 15 carrying the printing base 16 rises.

It is closely attached to the bottom surface of the screen printing plate 1.

■ Pressurization (Figure 2C) The air pump switches to pressurization, and the ink tank 9 is pressurized. Due to this pressure, the ink in the ink cell 6 passes through the screen gauze in the image area, and the resist 2 is placed below it.
This fills the space 3A formed in the printed pattern. The time it takes for the space 3A to be filled with ink is determined by the pressure and the connecting pipe 8.
．． Pressurization of the ink tank is continued until the time necessary to ensure that all the spaces are filled with ink, which is determined by the fluid resistance at the screen gauze 5, the viscosity of the ink, etc., has elapsed. Then, reduce the pressure in the ink tank again.

■ Separation (Fig. 2D) After that, when the stage 15 is lowered and the printing base 16 is separated from the screen printing plate 1, most of the ink in the space 3A adheres to the printing base 16, and a predetermined printing pattern is formed. A printed layer 17 is formed. After that, the printing base 16
is ejected, and one print cycle ends.

In the above printing process, the degree of air pressure is set to a relatively low pressure. The reason for this is that the degree of adhesion (pressure) between the screen printing plate and the printing base is finite.
If the ink pressure is extremely high, or if the contact pressure is too low, the ink will penetrate between the resist in the non-printing area and the printing base before or after filling the space 3A, and the desired print will not be achieved. This is because it may not be possible to reproduce the printed pattern. As a result of various experiments using the above-mentioned apparatus, it was confirmed that good printing was possible in a low pressure range of atmospheric pressure +1 kg/c+1 or less.

This means that with this level of pressure, even if the pressure is continued for longer than the time required to eject the amount of ink necessary to fill the space 3A, the space 3A will simply remain filled with ink. This means that the ink will not leak out from the space 3A and a predetermined pattern can be printed.

FIG. 8 is a correlation diagram between the ejection conditions (relationship between ejection pressure/ink viscosity and pressurization time) and printing results according to the above embodiment.

The vertical axis of the graph in Figure 8 is the value of discharge pressure/ink viscosity.

This corresponds to the ink flow rate when ink is ejected without bringing the printing base into close contact, and the horizontal axis is the pressurization time. The product (area) of these is the discharge amount when the screen printing plate and the printing base are not in close contact. When the ejection pressure is increased in the order of a-h l) -e (or the ink viscosity is decreased in the order of a-*b-C and the ink is closely ejected, the printing results for the pressurization time are shown in subscript 1.2.3. Here,
The area with subscript 1 indicates a situation where the amount of ink is insufficient and the specified printing pattern is not completely completed, and the area with subscript 3 indicates the situation where the amount of ink is excessive and ink leaks outside the specified printing pattern. The area indicated by the subscript 2 is an area where good printing is possible.

As is clear from FIG. 8, it was confirmed that there was a range in the appropriate pressurization time in all cases, and this range was wider as the discharge pressure was lower. Further, even if the ink viscosity changes, good results can be obtained if the ink is discharged for the time indicated by X in the figure. This means that even if a large number of inks with different viscosities are discharged at the same pressure, good results can be obtained with the same pressurization time, and the relatively expensive pulse control air pump of one device can be shared. leading to economic benefits. In addition.

By making the cell forming member 7 from a rigid body such as metal and supporting it with appropriate means, it is possible to increase the adhesion between the non-printing area around one printing area and the base to be printed. In this case, the width of the good printing area indicated by subscript 2 in FIG. 8 becomes wider as the pressing time becomes longer. Therefore, high-speed and stable printing is possible with a higher discharge pressure.

In the above embodiment, pressure is applied to the ink tank and the pressure is applied so that the ink is discharged from the screen gauze in the image area of the screen printing plate 1, but instead of this, the ink is discharged only by its own weight. Good too. In this case, either a structure in which the top surface of the ink tank is open to the atmosphere, or a structure in which the ink tank and connecting pipe are omitted and the top surface of the ink cell is open may be used, but in either case, the liquid level will affect the discharge amount. , it is preferable to control the liquid level height,
Further, although natural outflow was prevented by applying a reduced pressure to the ink tank, if the natural outflow from the screen gauze is small, reducing the pressure may be omitted. Further, in the above embodiment, a non-porous layer 2 having a thickness corresponding to the back surface of the screen printing plate 1 is provided.
Although the space 3A below the screen gauze is formed in the image area, it is also possible to omit the space 3A by controlling the amount of ink discharged from the screen gauze by controlling the pressurization time or the like. Furthermore, when performing monochrome printing,
It is not necessary to form an independent ink cell for each image, but a single ink cell surrounding the entire image may be provided.

〔Effect of the invention〕

As explained above, the method of the present invention utilizes a screen printing plate and applies ink by its own weight or under pressure through the screen gauze in the image area and onto the printing base below it. Ink is reliably supplied to the printing base, and desired patterns can be easily printed.

Since the printing pattern is formed on a conventionally widely used screen printing plate, arbitrary printing patterns such as single characters or subdivided figures can be manufactured precisely and at low cost.

Furthermore, the apparatus of the present invention is provided with an ink cell surrounding the printing area on the upper surface of the screen printing plate, an ink tank connected to the ink cell, and a means for controlling the pressure inside the ink tank. The ink tank, the ink tank, the connecting pipe connecting the two, etc. can be made of inexpensive materials such as rubber and plastic, and can be thrown away when the ink is replaced, so the equipment is inexpensive.

Ink replacement work is also easy. Furthermore, a general screen printing machine can be changed to the device of the present invention by simply placing the squeegee drive unit in a rest state and setting the ink cell, connecting tube, ink tank, pressure control means, etc. on the screen printing plate. can be used in conjunction with the present invention without losing its original function, making it extremely economical.

The method and apparatus of the present invention can print multiple colors at the same time by supplying color-adjusted inks to a plurality of image areas of a screen printing plate.

It is extremely suitable for printing printed matter 9, for example, color samples, which are printed in predetermined positions with slightly different tones.

[Brief explanation of drawings]

FIG. 1 is a sectional view schematically showing a printing apparatus according to a preferred embodiment of the present invention. FIGS. 2A to 2D are explanatory diagrams showing the printing procedure by the apparatus of FIG. 1. FIG. 3 is a schematic sectional view of another embodiment of the invention. FIG. 4 is a sectional view showing a modification of the ink cell provided on the upper surface of the screen printing plate 1. FIG. 5 is a sectional view of the stage 15 in the printing apparatus of FIG. 1. FIG. 6 is a sectional view showing a modification of the stage 15. 7A and 7B are cross-sectional views showing modified examples of the ink tank in the apparatus shown in FIG. 1, respectively. FIG. 8 is a graph showing characteristics during printing by the apparatus shown in FIG. 1-- Screen printing plate 2-- Resist (non-porous layer) 3-- Image area 4-- Non-image area 5- Screen gauze 6-- Ink self-- Cell forming member 8-- One connecting pipe 9-・
・Ink tank 11-・Air hose 12...
・Air pulse control section 13-compressor 15...
・Stage 16-・Printed base patent applicant Dai Nippon Printing Co., Ltd. Agent Patent attorney Kyo Matsu Sanga 5 illustrations Fang 6 illustrations

Claims (11)

[Claims] (1) Supply ink onto the image area on the surface of the screen printing plate, bring the printing base into close contact with the back surface of the screen printing plate,
A printing method characterized in that the ink is caused to pass through a screen gauze in an image area by its own weight or pressure, and is made to adhere to a printing target base below the screen gauze. (2) The screen printing plate has a non-porous layer forming a non-image area at least on the back side of the screen gauze, and when the base to be printed is brought into close contact with the back side of the screen printing plate, the screen in the image area 2. The printing method according to claim 1, wherein a space is formed between the gauze and the base to be printed. (3) The printing method according to claim 1 or 2, wherein the ink on the screen printing plate is pressurized by applying gas pressure. (4) The gas pressure acting on the ink on the screen printing plate is increased when the screen printing plate and the base to be printed are in close contact, and reduced when the screen printing plate and the base to be printed are separated. 4. The printing method according to claim 3, wherein the printing method is set to a state. (5) The pressurized gas pressure is atmospheric pressure + 1 kg/cm^3
The printing method according to claim 4, characterized in that: (6) The printing method according to claim 4, wherein the gas pressure in the reduced pressure state is selected so that the ink pressure at the lower surface of the screen gauze is approximately equal to atmospheric pressure. (7) a screen printing plate, an ink cell attached to the top surface of the screen printing plate and surrounding the printing area of the printing plate, and an ink tank connected to the ink cell in a sealed relationship;
A printing apparatus comprising: a pressure control means for controlling the pressure within the ink tank; and a drive means for bringing the back surface of the screen printing plate into close contact with the base to be printed. (8) The screen printing plate has a non-porous layer forming a non-image area at least on the back side of the screen gauze, and when the printing base is brought into close contact with the back side of the screen printing plate, the screen in the image area 8. The printing device according to claim 7, wherein a space is formed between the gauze and the base to be printed. (9) The printing apparatus according to claim 7 or 8, wherein the pressure control means controls the gas pressure on the upper surface of the ink in the ink tank. (10) The pressure control means includes a pulse control air pump capable of switching the gas pressure on the upper surface of the ink in the ink tank between a pressurized state and a depressurized state. 9. The printing device according to item 8. (11) the screen printing plate has a plurality of image areas,
An ink cell according to any one of claims 7 to 10, characterized in that each of the printing areas is provided with an ink cell, and each ink cell is connected to an independent ink tank. Printing device.